Since February 2021, Heat Treat Today has had the privilege of publishing the Combustion Corner. In each of these columns, John Clarke, technical director at Helios ElectricCorporation, shares his expertise on all things combustion. In this Technical Tuesday, we're taking a moment to review more of the key points from John's columns. As always, we hope this review helps you to be more well informed, and to make better decisions and be happier. Enjoy these five summaries of the second half of the Combustion Corner columns. To view each installment, click the blue heading below.
Process consistency and energy savings are inextricably linked. To lower operating costs and increase process consistency, John Clarke suggests asking three questions: What temperature is my furnace or oven, really? Do I have excessive safety factors built into my process to compensate for not knowing the temperature at the core of the part being heat treated? How much fuel can I save with a shorter cycle?
Reducing natural gas consumption is not the only way heat treaters can save money. Verifying internal furnace pressure, rebuilding door jams, and taking the time to consider if excess air is reducing combustion efficiency are all as good as cashing a check. Maintaining a consistently uniform furnace temperature saves more money than the energy conserved from using less fuel.
"To not invest money on worthwhile projects makes as much sense as not depositing your paycheck."
The biggest question mark in a heat treater’s mind is often, “What will natural gas prices be in the future?” Since we cannot know the answer to that question, what are some things heat treaters can do to prepare for unpredictable natural gas prices? Burner recuperation, using the waste heating exiting the furnace to preheat combustion air, is a tried-and-true method for reducing consumption. Before trying burner recuperation, the following questions need to be asked: How much will it cost? How much can be saved? Can the existing furnace accept the higher flame temperatures?
In this installment of the Combustion Corner, John Clarke takes some time to reassure the heat treating industry of two key facts about the United States' natural gas market:
40% of the electricity in the U.S. is generated using natural gas.
U.S production of natural gas was at al all-time high in 2021 and is rising. The U.S. is the largest producer of natural gas in the world.
With these two facts in mind, John postulates that the U.S. can be sure of a reliable supply of natural gas in the future, but, given the price differential between European and U.S. markets, American heat treaters are likely to see an increase in price per mmBTU.
Saving money is the same as making money. Adjusting the oxygen levels of flue products measured with a handheld combustion analyzer to operate at an optimal percentage may yield more savings than you think. Reducing a non-recuperated burner from 6% oxygen to 3% oxygen garners $17,792 extra a year for the heat treater. A quick solution with a hefty payback rate.
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Since February 2021, Heat Treat Today has had the privilege of publishing the Combustion Corner. In each of these columns, John Clarke, technical director at Helios ElectricCorporation, shares his expertise on all things combustion. In this Technical Tuesday, we're taking a moment to review some of the key points from John's columns. As always, we hope this review helps you to be more well informed, and to make better decisions and be happier. Enjoy these seven summaries of the first half of the Combustion Corner columns. To view each installment, click the blue heading below.
In his inaugural column with us, John Clarke sets up the Combustion Corner column series with a look at the basics of natural gas. What do heat treaters need to know about natural gas supply and demand, availability, pricing, and consumption. Plus, the risks heat treaters should consider when making decisions about maintenance and equipment acquisition.
Excess air is the percent of total air supplied that is more than what is required for stoichiometric or perfect combustion. In heat treating systems, excess air plays many roles, both positive and negative. The perfect mixture of oxygen and gas can be elusive. When it comes to saving money and improving safety, carefully monitoring excess air in fuel-fired systems pays dividends.
Maintain regular inspection and maintenance schedules
Combustion safety is the number one priority for all heat treaters. But, what factors should be considered when all safety considerations are in place? After all, many fire protection standards are designed to protect life and property (as they should be), but not the bottom line. The next priorities for heat treaters are: reduce burner failure and therefore reduce downtime, consider component failure rates when designing or purchasing a system, and maintain regular inspection and maintenance schedules.
Downtime is costly. In order to prevent downtime, heat treaters need to “plan the fix” before the fix is necessary.
Planning the fix entails more than an annual inspection. One way to address shut-down-causing errors before they happen is to carefully examine gas pressure switches; switch contact ratings, location, pressure ratings, and protection of the switch from “bad actors” in the fuel gas are all things to consider.
Pressure switches are either on or off. How can heat treaters use pressure switches to detect a possible failure before it occurs? The simple answer: the methods to analyzing time before shutdown is the heat treater’s crystal ball. Creating predetermined warning bands (time limits, which the pressure switch should not exceed or fall below) and monitoring switch response times within these predetermined times by PLC can give a glimpse into future shutdowns.
The NFPA allows for two arrangements of safety shutoff valves: the simple double block and the double block and vent. Both of these arrangements are appropriate as the last line of defense against a safety issue. How can heat treaters bring safety shutoff valves into compliance with NFPA 86? In this installment of the Combustion Corner, John Clarke clarifies how to comply with this common standard and lists some important considerations for choosing between a simple double block and a double block and vent arrangement.
In this column and the following columns in the series, John revisited the topic of natural gas. Reducing natural gas consumption is the best way to reduce cost. How can heat treaters do this? John suggests that we "optimize our processes, reduce unnecessary air, and contain heat within the furnace and/or capture the energy that leaves our system to preheat work or combustion air."
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Is there a way to combine pulse firing and fuel-only modulation without retaining the downsides of either method? Parallel positioning of burner controls may just be the win-win solution heat treaters are looking for.
This Technical Tuesday, written by Scott Fogle, national account executive at Siemens Combustion Controls, first appeared in Heat Treat Today's August 2022 Automotiveprint edition.
Scott Fogle National Account Executive Siemens Combustion Controls
Two common burner control methods for uniform furnace temperature needing Nadcap and AMS2750F requirements are pulse firing and fuel-only modulation. High convective heat transfer of the gases in the furnace results in good uniformity. Pulse firing keeps burners at high fire using on/off cycle times, and fuel-only modulation uses a constant high velocity of the combustion air. Both methods have a downside. When the cycle times of pulse firing are short for low temperature setpoints, the stirring effect is reduced, resulting in temperature uniformity challenges. Fuel-only modulation uses large amounts of excess air which is inefficient especially at high furnace temperatures.
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Parallel positioning offers a hybrid solution between pulse firing and fuel-only modulation. Parallel positioning independently controls the air and fuel on each burner. This control modifies the air-to-fuel ratio based on firing rate. At high firing rates of approximately 50% and above, the burner can be set to a stoichiometric ratio for the highest efficiency. When the firing rate falls below 50%, stoichiometric operation loses the high velocity stirring effect needed to obtain good uniformity. To maintain the stirring effect, excess air is added as the firing rate decreases. The air curve on a firing rate verses valve position chart looks like the letter “V.” Firing efficiently at high firing rates and adding excess air at low firing rates combines the best of pulse firing and fuel-only modulation in one solution.
Combustion curve
When conducting a temperature uniformity survey, parallel positioning offers flexibility to make minor adjustments to both the air and fuel of a burner. To correct cold spots and hot spots during a survey, there are four options available to tune the burner closest to the cold/hot spot at a particular firing rate: 1) increase air 2) decrease air 3) increase fuel and 4) decrease fuel. These adjustments of air and gas flow converge the temperature readings together for uniformity at multiple temperature setpoints.
Parallel positioning offers a couple other advantages as well. Many of these systems allow for an independent ignition position for each actuator: air and gas. A burner technician can set ignition for each burner at an elevated level and perhaps a rich mixture to increase the likelihood of reliable ignition in all cases, without compromising on turndown. If a specific firing rate and/or ratio does not suit a burner well, maybe the burner resonates or the flame signal weakens, the air fuel mixture can be adjusted independently at that point to minimize the undesirable characteristic.
Parallel positioning air fuel ratio control has been around for decades under the hoods of our cars, and for nearly that long in several large burner applications too. As these systems have become more reliable and less expensive, the benefits can be enjoyed by many other combustion applications. We’ve seen several furnaces take advantage of these benefits for improved operation in recent years.
About the Author: Scott Fogle is a national account executive with Siemens Combustion Controls based out of the Chicagoland area. He previously served as a combustion engineer for a globally recognized burner manufacturer. Scott holds 10 years of experience in the field of combustion and serves as an alternate on the NFPA 86 committee. Contact Scott at sfogle@scccombustion.com.
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N2: It’s so harmless, it makes up the majority of the air we breathe. But, once bonded with oxygen, the resulting compound can be dangerous to the environment and public health; as heat treaters know, keeping nitrogen oxide production levels low is a key part of complying with government requirements. When it comes to reducing nitrogen oxide levels, what options do heat treaters have?
This Technical Tuesday article written by Robert Sanderson, director of Business Development at Rockford Combustion, first appeared in Heat Treat Today's August 2022 Automotiveprint edition.
Robert Sanderson Director of Business Development Rockford Combustion
Nitrogen oxides (NOx) are a collection of highly reactive chemical compounds formed during combustion processes, partly from nitrogen compounds in the fuel, but mostly by direct combination of atmospheric oxygen and nitrogen in flames. One chemical reactant of NOx is nitrogen gas (N2). Formed by two nitrogen atoms, N2 lacks smell, color, and taste. N2 is also non-flammable and inactive at room temperature. In fact, N2 makes up 78% of our atmosphere, underscoring how little danger the compound, by itself, represents in the environment.
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However, when N2 reacts with oxygen (O), an assortment of nitrogen oxides such as nitric oxide (NO) and nitrogen dioxide (NO2) can be formed. All forms of the nitrogen oxides taken together are referred to as NOx, with the measurements reported as equivalent to NO2. NOx formation can happen naturally such as during a lightning strike, biogenetically in agricultural fertilizer, or from fossil fuel powered cars (mobile) and industrial combustion systems (stationary). Combustion processes that form NOx by-products predominately create them as both NO and NO2.
In this article we will look at NOx formed from combustion processes, why NOx is dangerous both to the environment and public health, and what options operators of industrial combustion systems have to reduce NOx emissions in equipment fi red by natural gas, oil, or coal. We will also show how reducing NOx in certain combustion systems can increase energy efficiency to bolster return on investment.
NOx
As a pollutant, NOx represents a serious threat to human health and the environment. When NOx is mixed with organic compounds under UV light it will create reddish-brown smog (ozone). Smog that envelops cities during the summer often degrades air quality and can irritate lung tissue. Additionally, NOx has been linked to acid rain and high levels of NOx have been shown to damage ecosystems by making vegetation more susceptible to disease and frost damage.
During the 1990s, the use of natural gas in industrial combustion processes displaced coal and oil. This has led to a significant reduction in NOx emissions. At the same time, local and federal requirements grew increasingly stringent, including the Clean Air Act Amendments of 1990 that required major stationary sources of NOx to install and operate reasonably available control technology (RACT). Current regulations in some parts of the country are focused on NOx levels of 9 ppm (parts per million) or lower. Manufacturers have responded to these challenges by introducing ever-lower NOx capable burners and NOx control schemes.
What Are the Types of NOx
As mentioned, whenever fossil fuel is burned, NOx can be formed. For that reason, motor vehicles by their sheer numbers are major contributors to NOx pollution. However, for the purpose of this article, we are narrowing the focus exclusively on NOx emitted by fuel-fired industrial combustion systems, such as boilers, furnaces, heaters, ovens, kilns, and dryers. NOx formed in high-temperature industrial systems can be broken down into three types: Fuel NOx, Thermal NOx, and Prompt NOx.
Fuel NOx
Although natural gas is typically free of fuel-bound nitrogen, nitrogen is often found in liquid and solid fuels. When nitrogen that is chemically bonded into fuel molecules is combusted, it directly converts to Fuel NOx. In fact, untreated fuel oil can contain as much as 1,000 ppm of fuel-bound nitrogen resulting in over 40 ppm NOx in exhaust. Ammonia (NH3) combustion is particularly difficult as it is essentially all fuel-bonded nitrogen, and fully converts to Fuel NOx. Hydrogen (H2) fuel combustion has no fuel-bound nitrogen and produces no Fuel NOx.
Thermal NOx
Sometimes called Zeldovich NOx, after the Russian physicist, Thermal NOx forms when airborne nitrogen and oxygen merge in high temperature zones. Thermal NOx constitutes most of the NOx formed during the combustion of gases and light oils. The formation of Thermal NOx is highly temperature dependent — basically the hotter the combustion the more Thermal NOx is formed. Thermal NOx generally begins to occur at about 1600°F, with formation rates escalating as the temperatures increase above this. But the formation of Thermal NOx is also dependent on pressure and residence time. Decreasing any of these three factors reduces Thermal NOx levels. Here, it is important to note that while natural gas is a cleaner burning hydrocarbon, all flames (including those of pure hydrogen) release heat. And any high temperature heat release has the potential to produce Thermal NOx. Many common Thermal NOx treatments utilize various methods to minimize temperatures in the hottest areas of the flame.
Prompt NOx
In 1971, Charles Fenimore proposed the concept of Prompt NOx. Prompt NOx occurs when N2 fuses with partially combusted fuel products early in a combustion process. Basically, Prompt NOx is the “leftover” NOx when both Thermal and Fuel NOx are accounted for. Although Prompt NOx represents a miniscule fraction of overall NOx in a combustion system, that fraction becomes in ever-greater proportion as other NOx control mechanisms are introduced. Prompt NOx is not thermally dependent which makes it difficult to design for. As such, it is often perceived as a source that cannot be easily controlled, hence suppression eff orts focus on reducing Thermal and Fuel NOx.
Why Is NOx Controlled?
Nitrogen oxides emitted into our atmosphere lead to increased air pollutants that irritate airways in the human respiratory system, among other health problems. Of course, air pollution impacts everyone but some of us are more susceptible: young children and seniors, those with asthma, and people working outdoors, for example. Even brief exposures to NOx can aggravate respiratory diseases, particularly asthma, emphysema, or bronchitis, leading to coughing, wheezing, difficulty breathing, and hospital admissions. Long-term exposure to elevated concentrations of NOx may contribute to the development of asthma and potentially increase susceptibility to respiratory infections.1 A 2012 United Kingdom study concluded that air pollution related deaths were more than double those of traffic accidents.2 A related study in the United States came to similar conclusions.3
The key problem is ozone. When exposed to UV rays in sunlight, NOx molecules interact with volatile organic compounds (VOC) to form ground-level or “tropospheric” ozone (O3), also known as smog. Smog can damage lung tissue, and it is especially dangerous to people with respiratory illnesses that may experience more intense attacks. Ozone is also hard on plants and animals, damaging ecosystems and leading to reduced crop and forest yields. In the United States, ozone accounts for an estimated $9 billion in reduced corn and soybean production annually.4 It also kills many seedlings and damages foliage, making trees more susceptible to diseases, pests, and harsh weather. Finally, ozone acts as a powerful greenhouse gas, albeit much shorter lived than carbon dioxide.
In the presence of water droplets, nitrogen oxides form nitric acid, contributing to the problem of acid rain. Additionally, NOx deposition in the oceans provides phytoplankton with nutrients, worsening the issue of red tides and other harmful algal blooms. A closely related molecule can be created, nitrous oxide (N2O), another greenhouse gas that plays a role in climate change.
Abating NOx Emissions
In response to stringent environmental regulations, the combustion industry has made important strides in reducing combustion associated NOx, while simultaneously furthering energy efficiency. These steps include a host of new and emerging technologies and practical, proven operational tactics, like the following:
Fuel Switching
One simple method to reduce Fuel NOx emissions is to switch from a high nitrogen-bound content fuel to a fuel with reduced nitrogen content such as another distillate oil, or natural or hydrogen gas — which are essentially nitrogen free fuels. Changing fuels may necessitate changes to burners, fuel trains, and burner management systems as the alternate fuel will likely have different combustion characteristics and chemical properties.
Natural Gas Reburning (NGR)
NGR has proven to yield NOx reduction up to 75% from standard burners. NGR involves building a “gas-reburning zone” on top of the primary combustion zone where natural gas is injected. A fuel-rich region is created where NOx reacts to hydrocarbon radicals and molecular nitrogen is formed. This technique can be built into some burner designs as an integral operating property. Burners that use this NOx reduction method must be carefully sized and examined for operating inputs as their performance ranges are often restricted.
Low NOx Burners
Low NOx and Ultra-Low NOx burners have been shown to reduce emissions by up to 50% compared to standard burners. Greater reduction efficiencies can be achieved by combining the burner with flue gas recirculation (FGR, see below). Low NOx burners reduce peak flame temperature by combinations of induced recirculation zones, staged or delayed combustion zones, and reduced local oxygen concentrations. Downsides of these mechanisms are that these designs are typically more expensive than conventional burners, often require a larger footprint, and they may necessitate extensive furnace modifications. These solutions are popular with volumetric air heating and low temperature combustion processes.
Reduced Oxygen Concentration
Under certain conditions NOx emissions will diminish in a near linear fashion with decreasing excess air. Decreasing the extraneous available oxygen in the combustion zone lengthens the flame, resulting in a slower heat release rate per unit flame volume. Keep in mind that if excess air falls below a threshold value, combustion efficiency may decrease due to incomplete mixing. This is a popular method of NOx control on tube fired burners, reducing furnaces, and other applications where combustion air is fully isolated from the process, allowing for precise management of oxygen levels.
Steam/Water Injection
As we discussed earlier, lowering the local oxygen concentration will slow combustion and reduce developed flame temperature, therefore decreasing the formation of Thermal NOx. One method to achieve this result is to inject a small amount of water or steam into the vicinity of the flame. The water will absorb heat as steam is formed, which lowers the flame temperature. Additionally, the steam displaces the available oxygen, which slows the rate of combustion and further lowers the flame temperature. This method is effective, but generally lowers the combustion efficiency by 2% as the water molecules absorb some of the thermal energy. The effects of trace minerals in the water should also be considered.
Selective Catalytic Reduction (SCR)
Ultra-Low NOx emissions (sub-5 ppm NOx requirement) are achieved with the use of selective catalytic reduction (SCR) technology. SCR is a post-combustion method that involves injecting an ammoniacal reagent such as ammonia, aqueous ammonia, or urea in the presence of a catalyst to convert NOx to harmless nitrogen and oxygen in the exhaust gasses. Ammonia-free solutions utilizing urea are an option for users averse to handling and storing ammonia. It is not unusual for an SCR unit to reduce incoming flue NOx levels from 30 ppm to below 5 ppm, or by upwards of 95% reductions of higher inlet concentrations. And they can lower the electrical load by reducing fan requirements compared to flue gas recirculation. Catalyst costs have steadily dropped since SCR’s introduction in the 1960s, yet transaction expenses generally make SCR a costly NOx reduction strategy. A common issue is ammonia breakthrough that can occur when excess reagent for various reasons “slips” past the catalyst unreacted. Some jurisdictions have limits not only for NOx emission limits but also for ammonia slip, complicating the use of SCR as an abatement strategy.
Selective Catalytic Reduction with Economizers
Incorporating an extended-surface economizer with SCR delivers low NOx emissions and higher system efficiency, lowering operational costs. The SCR is the first phase of the system, converting NOx to nitrogen and oxygen. The second phase is a finned tube economizer, capturing and redirecting wasted heat back via heat transfer to feedwater or makeup water. Increasing efficiency by one or two percentage points can amount to measurable cost savings. Users of this two-phase system also report higher turndowns (the ratio of maximum to minimum firing rate), more stable flames, and faster response times to load swings.
Flue Gas Recirculation (FGR)
FGR (5 ppm to 20 ppm NOx requirement) is a well-attested, pollution-reducing technology that reduces thermal NOx by decreasing the burner flame temperature and slows the combustion reaction. In the FGR process, a portion of flue gases generated during combustion is redirected to the burner with fresh air, which helps to cool down the flame’s peak temperature and slows combustion reactions, thereby reducing the formation of NOx. One downside of FGR is that flue gas recirculation requires electrical energy for additional air handling. Another issue is that not all thermal processes can use FGR, for example, if the flue gases are too hot or too high in oxygen.
Benefits of NOx control technologies range from lowering your business’s carbon footprint to maximizing fuel efficiency. When it comes to reducing nitrogen oxide levels, selection of options will depend on your thermal processing systems, site-specific conditions, and regulatory and economic considerations. With so many ways to control NOx levels, heat treaters can choose the option that works best for them.
References
[1] “Basic Information about NO2,” EPA.gov, United States Environmental Protection Agency, June 2022, https://www.epa.gov/no2-pollution/basic-information-about-no2.
[2] Roland Pease, “Traffic pollution kills 5,000 a year in UK, says study,” BBC.com, BBC News, June 2022, https://www.bbc.com/news/science-environment-17704116.
[3] Fabio Caiazzo et al. “Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005,” Atmospheric Environment 79 (2013): 198-208, June 2022, https://www.sciencedirect.com/science/article/abs/pii/S1352231013004548.
[4] Justin M. McGrath et al, “An analysis of ozone damage to historical maize and soybean yields in the United States,” June 2022, https://www.pnas.org/doi/10.1073/pnas.1509777112.
About the Author: Throughout Robert’s 32+ years of experience within the combustion field, he has been involved in the automotive, abatement-oxidation, aerospace, agriculture, food and beverage, HVAC, heat treating, glass, asphalt, pyrolysis, reducing furnaces, dryers, immersion heaters, and power generation industries. He has formerly worked with Eclipse, Honeywell, and Haden, Inc. and now brings systems integration, as well as the application experience of how systems interact in various environments to Rockford Combustion as the director of business development. Robert is a member of the NFPA-86 technical committee.
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Last month, we discussed adjusting the fuel to air ratio of our burners – which is always the starting point. This month we will discuss the value of preheating combustion air using the waste energy in the furnace’s flue products to reduce our fuel consumption. This is commonly referred to as recuperation.
This column is a Combustion Corner feature written by John Clarke, technical director at Helios Electric Corporation, and appeared in Heat Treat Today's August 2022 Automotiveprint edition.
If you have suggestions for savings opportunities you’d like John to explore for future columns, please email Karen@heattreattoday.com.
John B. Clarke Technical Director Helios Electric Corporation Source: Helios Electric Corporation
Natural gas prices continue to be a concern for our industry. We did see some short-term price relief in the U.S. because of the explosion at a Houston area LNG export facility that will reduce the U.S. ability to export natural gas for the balance of the year. Even so, there are LNG export expansion projects that will be completed in the coming year that will further expand the movement of North American natural gas to Europe and Asia. The result is that the U.S. price for natural gas will be more closely aligned with the price paid abroad. It appears the long-term factors influencing the price of natural gas in the U.S. remain unchanged — so, what should we do?
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We will continue to use the same typical furnace as last month — where after adjusting the fuel to air ratio, the furnace consumes $110,208 in natural gas per year. This furnace operates at 1600°F with an exhaust temperature of 1700°F. We have purchased and installed a recuperator that preheats the air supplied to the burner to 800°F. How much can we save?
If we locate our exhaust temperature in the left-hand column and find where it intersects with the preheated air column — the estimated savings is 32.3%.
Table 1. Savings from preheating combustion air
Recuperation requires a great deal more investment than simple fuel to air ratio adjustment. The projects are involved and generally require the burners be replaced or upgraded. There may also be the need to upgrade combustion air blowers and controls. Recuperation also alters the peak flame temperature the burner produces and can impact the temperature distribution within the furnace. Higher flame temperature may lead to increased NOx emissions as more nitrogen is oxidized. In most, if not all cases, these factors can be addressed with the selection of the right combustion equipment. So, assuming we wish to achieve a three-year payback — we can budget up to $106,000 for this project.
Recuperation is but one way to make use of the energy in the flue products that we would otherwise throw away. The exhaust from our burners can be directed over work to preheat it before introducing it into the furnace. The flue products can be used to generate steam so the energy can be used elsewhere in the facility.
The optimist may look at higher natural gas prices as an opportunity to gain an advantage over our competitors while the realist will see it as an imperative that we work to minimize the impact of rising costs. Either way, the path is the same: optimize the efficiency of what we have, then determine if further capital investments make sense. Next month we will discuss these steps in greater detail.
About the Author:
John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.
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In thisHeat TreatRadioepisode, host andHeat TreatTodaypublisher Doug Glenn learns about a never-before-seen combustion system tuning technology from Justin Dzik, manager of business development, and Ben Witoff, manager of data engineering, at Fives North American Combustion, Inc. Hear from the experts themselves how this system will save time, money, and personnel and can be adapted to virtually any furnace system.
Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.
The following transcript has been edited for your reading enjoyment.
Doug Glenn (DG): This is kind of a new technology that I haven’t seen before in the market. We’re going to be talking about combustion system tuning. We have here with us today Justin Dzik from North American Combustion and also Ben Witoff. Justin is the manager of business development there in Cleveland and Ben is the manager of data engineering. We’re going to hit on, I think, what is a pretty interesting new product that you guys are developing. When I first saw and heard about it, I thought, “ I have not heard of anything like this before.” I think our listeners and viewers will find it of interest.
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The name of the product is called CertiFire™. Before we get too far into it, Justin, if you don’t mind, can you give us just a brief background about you? And why don’t we have you, if you don’t mind, just give us a thirty second blurb on Fives North American Combustion, as well, please.
Justin Dzik (JD): As Doug already said, I’m the manager of business development and I’ve worked at Fives for 15 years now in various different roles, primarily focused on the forging and heat treat markets doing uniformity tests, and that’s really why this product is so close to us.
Fives North American is a company that has been around for about one hundred years; it’s located in Cleveland, Ohio. We produce combustion equipment, but we also do turnkey systems, we do furnaces, direct-fired furnaces for the forge heat treat but we also supply combustion equipment for pretty much every industry that needs heat, which is quite a bit.
DG: I would like to mention also for those of you who are old-timers, somewhat like me, Fives North American Combustion should be recognizable. The old company name was just North American Manufacturing. They are in the Taj Mahal on Grant Street just south of downtown Cleveland.
Ben, how about you? If you don’t mind, give us a quick blurb about yourself and your role there.
Ben Witoff (BW): I’ve been here just about 10 years; my 10-year anniversary is going to be next year. I’ve worked in various R&D roles since I’ve been here. I started as a burner designer, worked with FEA CFD modeling, moved into thermal processing engineering, and then, just a few years ago, I started the data engineering department here so that we could try to augment our combustion and industrial equipment with sensors, with IoT, with data, with smart engineering, and just to try to take a step further.
DG: Industry 4.0, IoT and all of that stuff is very, very interesting. That’s what caught my attention on this thing.
Justin, without going into any great detail, if someone only watched the first two minutes of this podcast, from a 30,000-foot view, what is CertiFire™, and why should people care about it?
JD: The CertiFire™ is, as you already stated, an automated tuning device for temperature uniformity certifications. I think pretty much everybody that’s going to watch this podcast is probably going to know that they can be extremely time consuming to do, they take a lot of time and a lot of intelligence to actually tune the process. This device takes all of that and does it all itself. It does all the automated burner tuning, all the valve adjustments, it locks it all in and tunes it for whatever class uniformity you need.
DG: I did want to hit on that, too, because we’re talking about trying to tune the combustion system on a furnace so that that furnace is running, first off, optimally (not wasting energy), but also, we’re talking about trying to make that system uniform, trying to make the work zone uniform, inside that furnace. So, again, most people will already now this, but it’s always good to hit on some basics here, because there may be people listening that don’t know some of the basics: why is this work zone uniformity, the area inside the furnace, why is it important that it be uniform? And then, if you can, maybe hit on what we mean when we say, “furnace classifications.”
JD: Obviously, it’s important because the parts that are going into these furnaces can be used for a variety of applications, like everybody knows, aerospace being a primary part class that’s going in. Because of that, and the metallurgy required, everything needs to be within a certain temperature band in order to get the same metallurgical properties, after they forge it, or heat treat it or whatever. So, it’s extremely important to make that work zone as tight as possible and as consistent as possible, and as we can all imagine, having a work zone about 3 or 4 feet away from essentially a live fire coming out of a burner, is extremely difficult.
As you said already, there are classifications, there are different codes that govern the work zone classifications like AMS2750 Revision F is the most recent one, Rolls Royce has their own, and pretty much all of the aerospace suppliers have theirs. So, the classifications really govern how tight the uniformity band has to be in that work zone.
There is class 1 which is basically ±5 degrees Fahrenheit anywhere in that work zone and it goes all the way up to class 6 which is ±50 degrees, so much more lenient. Obviously, class 1 is the hardest, probably all heat treat stuff; class 6 is probably some heavy forgings.
DG: As we move up the furnace classifications, as we move up from going ±5 to ±50, the lower classifications are where it’s really critical that any type of heating source, whether it be electric heating elements or combustion, be well tuned because you want the whole entire work zone to be uniform.
But we’re talking specifically about combustion tuning. Justin, I’ll address this with you and then Ben- I’m coming to you with the next question: How have combustion systems typically been tuned in the past — in fact, I would say probably 99% of them are still tuned even now — and what are some of the major issues that we run into in the way we’re currently doing it?
JD: Obviously, there is a variety of complexity of systems out there. There are furnaces still in operation that we put in in 1960. The number of valves they have on there, they’re probably more manual valves so there’s a lot of manual tweaking of things going on right at the burner. The more advanced systems out today have automated valves, but you’re still doing manual adjustments in a PLC, probably, that you’re trying to tweak. Everybody knows, and I think Ben really likes to use this statement: it’s a game of whack-a-mole. You adjust a burner here and it goes out of compliance over here and so you run over there. I’ve been on hundreds of surveys where I’m running around the furnace trying to watch my temperature map that I have in my hand. It can get very tedious, and it takes a lot of know-how and a lot of experience, I believe, to tune these furnaces.
DG: So, there is, I believe to a certain extent, an art to it now, very much dependent, I’m guessing, on your specific furnace, your specific burner, your specific burner configuration, and what mode of combustion you’re using, whether it’s pulse fire or whatever, right? All of those things are “the art of combustion.” It kind of takes us back to that black art that heat treaters are trying to avoid, where you’ve got to figure it out, each one individually. CertiFire™ is basically going to help us eliminate that.
Ben, if you don’t mind, how does CertiFire™ work, why is it better, and what kind of results do you think we can get in the sense of amount of time spent trying to tune a system and uniformity?
BW: As Justin mentioned, I love using that term “whack-a-mole.” I think it’s a great way to describe it, it’s a great way for people to understand. You bop down one of those thermocouples, you get it into the right temperature, and then the next one popped right back out. And the reason that happens is because these furnaces are nonlinear systems.
When you look at the inputs and you look at the outputs and you try to model it just from a purely physics or mathematical perspective, it’s not something that can be tuned linearly, you can’t just adjust a valve and then adjust the second valve and expect all of the adjustments from the first one to carry over. You’re constantly throwing one thing out of whack when you bring another thing in.
You also touched on this with your other question: there are so many other factors that affect the uniformity of the furnace. If we built five identical furnaces in our factory and got all of the burners set up identical and we shipped then out to five different locations, they’d all be different — completely different — because it’s the humidity on that day, it’s the temperature, it’s the elevation that it’s installed, it’s whether or not the facility is indoors or if they have their garage doors up- there are so many different factors that affect it. It’s the humidity when we mix the refractory on that day that affects it.
So, you can’t just tune it, forget about it, and ship it off. It needs to be done on site. And today, it’s kind of that “art” — it’s someone that is highly trained, they have years of experience to do it. They’re the “furnace whisperer,” they can figure out exactly how they get those systems into tune.
So, what we did is we took a step back and we said- how can we try to approach this mathematically? The first thing that we identified is we cannot be adjusting one at a time. You don’t adjust burner one and then look at the temperature readout and then adjust burner two. We can’t do it that way. So, we said we have to figure out how we can model that 3D space, those inputs and those outputs and that relationship between them, and that’s the fundamental nature of what the CertiFire™ does.
Photo Credit: Fives North American Combustion, Inc
We use this phrase “response matrix” and this is the way that we’ve created this virtual map of the furnace. It maps all the inputs — those burners, those heat sources — to all the outputs — those thermocouples in the work zone, that temperature measurement point.
And what we do is we go through this training phase for every furnace where we modulate our burners, we change the firing rate in a known way for all of the burners and then we measure exactly how those temperatures of those thermocouples in the work zone change. And the way that they change, the speed at which they react, the amount of time it takes to heat up and cool down, and the exact 3-D map of where those thermocouples are and how they react to each burner and where those burners are, is what this response matrix is.
The beautiful thing about the math behind it is you can solve the equation forwards or backwards. So, it’s easy to modulate a burner; it’s an independent variable. You can tell exactly where to be. You don’t know where the temperature is going to be, but you can measure it once you modulate that burner. So, that’s our equation.
We build the forward equation, and the beauty of CertiFire™ is we just flip it backwards. We solve it the other way. We say, “Where are all our thermocouples today? What’s our survey temperature?” All right, well, this one is 5 degrees hot, this one is 20 degrees cold, so you have all of your ΔT’s and then you say- well this if is my array of delta T’s, then divide by their response matrix. What’s my array of delta burner adjustments?
So, it solves for all the burners simultaneously, it takes all the adjustments into account, it gets rid of that whole whack-a-mole game, and it tells you burners 1 through however many you have need to be adjusted x% up, x% down, you do the adjustments, it looks at it and says, “Is it good enough?”, and if not, make another adjustment.
DG: Very interesting. So, this is all done through algorithms and things of that sort, I assume, the “secret sauce.”
BW: Right, exactly. It’s some fairly simple math but it’s this matrix math where we’re trying to model multiple inputs and multiple outputs, and we’re trying to map N-inputs to M-outputs. It’s not necessarily linear still but we’re making these linear approximations for a nonlinear system.
DG: I’m going to create a fictitious persona here and ask you about the capabilities: I’m a guy who owns a furnace that is a class 4, class 5, class 6 — let’s say it’s not super-precise as far as temperature uniformity (±15 or upwards). It’s an older system. I’ve got old burners on there, and I’ve got old valving on there. In order to use the CertiFire™, do I need to update those burners and/or valving so that it can be precisely tuned, or does the CertiFire™ work on any type of current combustion system?
BW: I guess I would say yes and no. I’ll get into the details on that because it can be kind of a confusing or irritating answer. I’ll start with yes, because the fundamental algorithm really doesn’t care that it’s a furnace at all, it doesn’t care that it’s a cube, it doesn’t care that it’s X number of burners or whatever dimension. The fundamental algorithm is simply that you map inputs to outputs, and they can be any different size, they don’t have to be the same size, and then it allows you to solve it backwards. The fundamental algorithm, the piece that is the heart of the CertiFire™ can absolutely work on that furnace.
The reason I said no is because the first piece of technology we’re trying to tackle with the CertiFire™ is a more advance PLC controlled system. The way that we do tuning today is we use actuated bleed valves per burner on our furnaces so that we can make that fine tuning automatically through a PLC adjustment. Because the PLC can control those actuated bleed valves per burner, it’s really simple for a device to just simply plug in with the data cable and then immediately take over the furnace and make these adjustments automatically at the push of a button.
That’s the first tier of furnace technology that we’re trying to tackle, that we’re trying to release a product for. What we’re working on after that tier, our lower tiers, are furnaces where customers are wanting to retrofit to a bleed valve system and then, finally, after that, are customers who are unwilling or don’t want to upgrade to that retrofit system.
Because no matter how you make that adjustment, the easiest way is a bleed valve if you already have it. But no matter how you make it, if it’s eliminating orifice valve and it’s a technician with a screwdriver in his hand, it’s the same algorithm. The only difference would be the CertiFire™ HMI may print out a sheet of paper that the guy can walk around the furnace with or he’s carrying an iPad and it says “Burner 1, quarter turn right, burner 2, eighth turn left.” He can make them one after the other in series because the solution itself is still a parallel solution.
DG: Obviously, it’s going to take more time and there’s more manual interaction there with that latter example you were giving.
BW: Right. But it’s certainly not more manual than they would tune it without the CertiFire™. It doesn’t take that furnace whisperer technician to get that done — anyone can use that sheet and make the adjustments that it tells them to make.
DG: It sounds like, with yours, even if you’re doing the adjustments manually, let’s say, in your latter example, you’re going to go out and you’re going to make an adjustment to all 12 burners on your furnace and come back and see how that goes. Whereas if you’re the whack-a-mole furnace whisperer, he’s going to go out, adjust one, come back, see how it goes, go back out and adjust another one. So, that makes some sense.
Photo Credit: Fives North American Combustion, Inc.
How about installation of this thing? You mentioned data cables and things of that sort. How complicated is this thing to install, and how much time to install?
BW: Starting with the first tier of customer that we’re trying to talk about here, if there is an existing furnace, if it has the panel that we built for this customer, if they have these bleed valves with actuators on them talking to the PLC today. If we were to walk into that facility, we would have a box that is literally plug-and-play. It needs power, it needs data, and then your HMI has a green “go” button on it. It’s something that we would preconfigure because we’d understand the tags inside of the PLC and how to communicate to all of the valves. It would actually be that simple.
If it was built by somebody else or it was an older panel or we didn’t know how the PLC worked, it would probably take some time for us to understand it from the controls perspective so that we could get all of the tags coded properly, but that’s not anytime where the customer is not running. They’re still running, we’re just in the background reading some PLC information.
And then, finally, if this is a customer that wants to add that equipment, if they’re looking to upgrade if their equipment is older, or maybe their class 5 today but they really want to be class 3 or maybe even class 2, we would probably suggest, with or without CertiFire™, to upgrade to those bleed valves per burner. We think we can get better control with that and in that case, maybe the customer has to shut down the furnace for a week while we do the installation and then once it’s installed again, it would really be that simple as a plug-and-play device with a data cable.
DG: Justin, I’ve got a question for you, now: I can imagine that some of the viewers/listeners are wondering, “Yes, I’ve got a combustion furnace I’d like to do this. Does it make sense for my furnace?” Are there any systems out there that you can think of, any furnaces with combustion, where the CertiFire™ would not make sense? Are there any applications or anything along that line?
JD: Honestly, I think that if you need to comply or certify your furnace to any uniformity standard, The CertiFire™ could definitely help. As Ben stated, there are different tiers of the product and how it would actually be from the customer experience. From a totally automated state to one where CertiFire™ is like the assistant to the person performing the tuning. But there are no configurations — step fire, pulse fire, excess air modulated, everything under the sun — the CertiFire™ can help solve those problems for them.
DG: So, I assume the aluminum industry, steel industry, heat treat industry, generally speaking, have no problem firing into radiant tubes?
JD: So, obviously, we’re at the beginning of the launch of this product, so where we’ve focused on is direct-fired heat treat furnaces and torch furnaces, and we’re looking to branch out into other things. We’ve even had discussions internally of using this on resistive heaters for electric heaters because we know “the green wave” is coming. The product itself has been, I think, stated pretty well.
The algorithm has no idea that it’s even a furnace. It could be applied to pretty much everything. I think this is going to be one of those products where we made it for this — we do this all the time with our burners — and then we find all these other ancillary uses for it because it’s such a revolutionary kind of idea.
DG: As you were talking there, I was thinking to myself, “Yes, you know, if you designed it so far for direct-fired, to a certain extent, radiant tube applications might add a little more complexity to it because you’ve got heat transfer rates through a tube, but, I suppose, still, it’s going to do the job because it doesn’t know.
JD: Yes. There is a thermocouple having a response and then there is this burner input. The way the heat transfer happens is going to change, but you’re going to have to modulate the radiant tube to get where you’re going to need to go.
Photo Credit: Fives North American Combustion, Inc.
DG: So, it’s “heat source agnostic,” we’ll call it.
Does this system have any type of reporting? I guess you did say, Ben, that after you do the first test and establish the response matrix, there is some sort of a report, I assume, when you want to tune it, but what is the reporting, what’s it look like? What are people going to get from this thing? And I guess I want to ask about the platform that it’s on, I guess it’s just PLC-based, right?
BW: The tuning is done through the PLC because it’s communicating with those actuated bleed belts. The actual box itself is essentially a computer, so it’s running our own custom code and it’s executing that to communicate with the PLC. We’ve tried very hard to make it PLC agnostic so it can communicate with the most common things we see in the market today. It can communicate over common protocols like Modbus, it can communicate with Rockwell’s EtherNet/IP or Viessmann F7. So, that is essentially just a computer — it’s a Linux box that can talk all of those languages at once, so it can just plug-and-play with the PLC.
The reporting we’ve tried to make look similar to what people are used to. People are used to looking at chart recorders to see temperature, so we have essentially a more advanced display of live data, chart recording for temperatures for valves that you can see exactly where it is with historical data easily available at a click and drag so you can see where it was and where it is today.
As far as an output of the report, we’ve also tried to make that look, as much as possible, like what people are used to seeing. With the AMS certification, there are guidelines about what data needs to be stored, what needs to be reported, and while we’re not doing the certification, that type of time-stamped temperature by furnace ID, by who ran the test — all of that information is generated in these reports every time that you do this response matrix as training creation, and then every time that you solve that and do this tuning of the combustion system.
DG: I can see some people wondering about this: Is it Cloud-based at all or is it all on site?
BW: It’s entirely on site. There is certainly the option. I know some customers (although it’s rare but it is growing today) want their information to be more accessible than it is today. But if a customer doesn’t want that, if they want everything restricted to plant, if they want it restricted off of the plant network and even adjust on the box itself. We can do that as well. Today, we don’t have Cloud connectivity built into the base box. We wanted to make it simple, we wanted to make it easy for customer compliance. It’s an option, it’s something we can do, but it’s not something we wanted to pursue in the first release.
DG: You’re avoiding a lot of potential internet cybersecurity issues with that.
I have a forward-looking question for you. By the way, I should mention, I’m sure by the time people listen to this, the AISTech Show will be over because it’s scheduled for next week (we’re recording this on the 10th of May and it’s scheduled for the 17–19th). I know that you guys are giving a presentation there so perhaps we can reference that on this podcast and give a link for it. . . CLICK HERE.
I know you’re just launching it. Actually, when did you launch it? Has it been weeks, months, or a year?
JD: I think it’s been about a month.
DG: So, it’s relatively new. As I say, we’re doing this on May 10th, so let’s say, April or late March you launched this thing. Have you put any thought into the future? Do you have dreams and hopes, and, if so, what might they be?
JD: Absolutely, we have some plans. Some immediate plans are we’ve talked about the tiers and how we’re going to keep pushing forward with making this a product that is for all furnaces for all direct-fired furnaces, to start, with manual valves and automated valves, so we’ll get to the tier 1, 2, 3.
Then, a big trend we’re hearing as we’re talking to customers is more gear towards predictive maintenance. Obviously, we need to tune the furnace, but the customers don’t want you tuning the furnace every time they need to certify because that calls into question their parts from the last quarter or half year that they’ve been doing.
So really you tune once and then you probably go a year; hopefully on our furnaces we go many, many years without drifting. But the box can also be used for some predictive maintenance. Use the thermocouple inputs that we have to measure the box shell temperature, see if the fiber is degrading, see if you’re up for a realign, see if your flows need to be readjusted. So, there’s a more predictive nature to the retuning process rather than a reactive nature. That’s really going to be the next step.
Then we’ll look forward to see if there’s other type of heating — like you said, radiant tubes or resistive heating. I think that’s a little bit further in the future, mostly because we’re, obviously, a gas combustion company so we’re focusing on what we know first and then we’ll build out from there.
DG: So, you’re saying some of that stuff that you’re hoping for the future is not really even combustion related, you’re going to be doing condition of the furnace.
JD: Right, like a furnace health monitor. I think everybody wants to know they’re running that furnace pretty hard (especially in a forge environment, you’re beating the hearth pretty good). To have a one-month out warning, “Hey, you might need to shut down, rather than a catastrophic failure.” We’ve gone into furnaces too much where there’s been a hole in the roof, because the fiber fell out or they just didn’t know about it. We’re trying to help customers out before something like that happens.
DG: Right now, I know almost all of the burners (the stuff you’re currently doing) are all hardwired, correct? Is there any thought about making them wireless? Is that even a reasonable thing to think about or not?
JD: From the burner standpoint or from the CertiFire™ standpoint?
DG: From the CertiFire™, in the sense of controlling and getting the data in and out. Maybe it’s a silly question, but I was just wondering. Right now, you’re just hardwiring all this stuff.
JD: That’s correct. Generally, that’s currently the way furnaces are configured. They’re all hardwired to a local PLC. Ben could probably speak a little bit more about it. I think we’ve talked about ways to wirelessly link devices more as diagnostic devices, not controlling wirelessly. You can’t really control them wirelessly because of the response time, but diagnostic components could be wireless.
BW: One of the first things that we did when the CertiFire™ was in prerelease was we were designing this box to essentially plug and be installed on that furnace. Then we took a step back and we tried to consider who’s going to be using this, how do they want to use it, what do their facilities look like?
A lot of people have multiple furnaces — maybe as little as two but sometimes upwards of twenty furnaces. Maybe you don’t want to install it permanently, maybe you want to be able to move it around, or maybe if you have a plantwide network and intranet there, you can plug this in your control tower and you can sit in an airconditioned room with one CertiFire™ and talk to every furnace at once.
That’s something that we put into that release from a month ago so the release CertiFire™ can communicate with all of your plant network at once (if you have the plant network), or just with that one furnace if you want to plug it into that one isolated furnace. We should be able to essentially it fields wirelessly you can communicate to whatever is on the network at once.
JD: Like you said already, we’ll be AISTech next week, (it will probably lapse this podcast). Then, I’ll also be presenting at the IFC (International ForgeMasters Congress) in June and with future engagements at Furnaces North America. This is our roadshow this year.
DG: You’ve got a lot to talk about! Like I said, I don’t know about you, and I know the answer to this question but I’m going to ask it anyhow.
BW: Nothing that I’ve seen.
DG: I don’t think anybody else has anything like this, as best I know. If they did, they’d be foolish to say so. But I haven’t seen it. I don’t know. Maybe they are and I’m going to catch grief for saying that.
It’s an interesting new product and I wish you guys well. I hope you’re very successful.
Good to have you with us, guys. Thanks very much for joining us.
This presentation was featured in a Heat Treat Radio episode with Justin Dzik, manager of business development, and Ben Witoff, manager of data engineering, at Fives North American Combustion, Inc. In the episode, Heat Treat Radio #77: Algorithmic Combustion Tuning With Justin Dzik and Ben Witoff at Fives, Heat Treat Today publisher Doug Glenn learns about a never-before-seen combustion system tuning technology from Justin and Ben. Hear from the experts themselves how this system will save time, money, and personnel and can be adapted to virtually any furnace system.
An excerpt from the episode:
"Where we’ve focused on is direct-fired heat treat furnaces and torch furnaces, and we’re looking to branch out into other things. We’ve even had discussions internally of using this on resistive heaters for electric heaters because we know 'the green wave' is coming. The product itself has been stated pretty well. The algorithm has no idea that it’s even a furnace. It could be applied to pretty much everything."
To not invest money in worthwhile projects makes as much sense as not depositing your paycheck. In this column, we will briefly look at energy and gas “checks” you might have received in the mail but have yet to cash.
This column is a Combustion Corner feature written by John Clarke, technical director at Helios Electric Company, and appeared inHeat Treat Today’sFebruary 2022 Air & Atmosphere Furnace Systems print edition.
If you have suggestions for savings opportunities you’d like John to explore for future columns, please email Karen@heattreattoday.com.
John B. Clarke Technical Director Helios Electric Corporation Source: Helios Electrical Corporation
The late Fred Schoeneborn, a long-time energy consultant and friend, described energy savings opportunities that have been identified but not exploited as uncashed checks. To expand on Fred’s metaphor, not to look for opportunities to save natural gas is the equivalent of not collecting and opening your mail.
A furnace or oven is a box that contains the work being processed and the heat used in the process. It is an imperfect box because we are always losing heat. While it is imperfect, there are often opportunities to improve your oven’s performance, saving energy and generally improving quality. (You may notice if you have read a few of my columns, energy savings and quality improvements nearly always coexist.)
At the start of this series, we asked several questions. This time we will consider the following:
Is my furnace or oven at the correct internal pressure?
Is it time to rebuild door jams?
How much fuel is wasted because I am not containing heat within the furnace or letting excessive air reduce my combustion efficiency?
Furnace pressure (in a non-vacuum application) is the simple function of the volume of the material introduced vs. the area of all the openings in our box. The obvious inputs are the products of combustion for direct fired systems, or the atmosphere for indirect systems.
What is the optimum pressure for my system? In general, the best pressure is the lowest pressure at which no tramp or unwanted air can enter the system and contaminate the atmosphere or upset the temperature uniformity. The lower the pressure, the less chance we will have excessive losses around door seals or other furnace penetrations. Most commonly, these pressures are measured in the hundredths or tenths of inches of water column.
In many applications, door sealing surfaces or jams take quite a beating. Their maintenance is expensive in terms of money, labor, and lost production. Expensive, yes, but the cost of NOT maintaining these surfaces may be much more. Losses are a result of radiant and convective losses, but most significantly, product quality because of atmosphere contamination or areas of the furnace not reaching setpoint temperature. When should we maintain these surfaces? In general, the best results I have observed are people who schedule surface maintenance periodically based on wear and available furnace downtime.
Calculating the savings from these fuel savings is more difficult, but in general, maintaining a consistently uniform interior work area saves more than the energy conserved.
About the Author:
John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.
Doug Glenn, publisher of Heat TreatToday, moderates a panel of 5 experts who address questions about the growing popularity of hydrogen combustion and what heat treaters need to do to prepare. Below is an excerpt of this lively and compelling discussion.
Today’s Technical Tuesday was originally published in Heat TreatToday's December 2021 Medical & Energy print edition.
Introduction
Doug Glenn (DG): Welcome to this special edition of Heat Treat Radio, a product of Heat Treat Today. We’re calling this special episode “Heat Treat Tomorrow: hydrogen combustion. Is it our future or is it just a bunch of hot air?” This discussion is sponsored by Nel Hydrogen, manufacturers of on-site hydrogen generation systems. I’m your host, Doug Glenn, the publisher of Heat Treat Today and the host of Heat Treat Radio. I have the great privilege of moderating this free-for-all discussion today with five industry experts who I’d like to introduce to you now.
Perry Stephens Electric Power Research Institute (EPRI)
Dr.-Ing. Joachim G. Wünning President WS Wärmeprozesstechnik GmbH
First, Perry Stephens. He is the principle technical leader of the Electric Power Research Institute (EPRI) and currently leads the end-use technical subcommittee of the low carbon resource initiative (LCRI) which is a collaborative eff ort with the Gas Technology Institute (GTI), and nearly 50 sponsor companies and organizations. They aimed at advancing the low carbon fuel pathways on an economy-wide basis for the achievement of decarbonization. EPRI is a member of the Industrial Heating Equipment Association (IHEA).
Joachim Wuenning (Joe Wuenning) is the owner and CEO of WS Thermprocess Technic Gmbh [WS Wärmeprozesstechnik GmbH] in Germany and WS Thermal Process Technology, Inc. in Elyria, Ohio. Joe’s company has been on the cutting edge when it comes to hydrogen combustion. In fact, the last time I heard you, Joe, was at the Thermprocess show in Düsseldorf, where you gave the keynote address regarding the advent and development of hydrogen combustion. Joe’s company has been a leader in hydrogen combustion. Joe’s company is an IHEA member as well. Joe is our European representative, and may provide us with a different perspective.
John Clarke is the technical director of Helios Electric Corporation (Fort Wayne, Indiana), a company that specializes in energy and combustion technologies. John is also a regular columnist for Heat Treat Today and a past president of IHEA.
Jeff Rafter is vice president of sales and marketing for Selas Technologies out of Streetsboro, Ohio and has a rich history in the combustion industry as well, including many years with Maxon Corporation. He’s got 28 years of industrial experience in sales, research and development, and marketing. He’s a combustion applications expert in process heating, metals refining, and power generation and has also served 10 years on the NFPA 86 committee and holds a patent for ultra-low NOx burner designs. He is also an IHEA member.
Finally, we have Brian Kelly with an equally rich history in combustion, spending most of his years at Hauck Manufacturing in Lebanon, PA, where he did a lot in sales and engineering before they were purchased by Honeywell. Brian currently works for Honeywell Thermal Solutions and is also an IHEA member.
Gentlemen, thank you for joining us. Let’s just jump right in. Brian, since I picked on you last, let’s go to you first on the questions.
John B. Clarke Technical Director Helios Electric Corporation Source: Helios Electric Corporation
Jeff Rafter Selas Heat Technology Company, LLC
Brian Kelly Honeywell Thermal Solutions
Is Hydrogen Combustion the Future?
DG: Is this hydrogen combustion thing coming? And, if so, how soon and what’s driving it?
Brian Kelly (BK): It is coming and there is going to be a lot of back and forth in that it doesn’t make sense and all that. It is here. We’re seeing inquiries from customers that ask, “Hey, do we have burners that do this, control systems and stuff that do that?” The news that I get emails on, for example, is that with one of the steel companies in Europe, they already said their plan is totally going to be hydrogen. We’re delivering billets right now of hydrogen.
So, yes, it’s coming. Is it coming soon? It’s here today. Widespread? That’s going to be a longer road. I think you’re going to hear from people that know more about it than I do, but, certainly from industry buzz, we’re testing burners, we’re making sure our burners run on partial hydrogen, full hydrogen, safety valves, control valves, and all that is definitely within a lot of the testing that we’re doing right now beyond the usual R&D on lower emissions burners and things of that nature.
Jeff Rafter (JR): I have a slightly different answer, but I agree with Brian. I think hydrogen combustion has been here for over a century. The difference has been, it’s been largely restrained to a few industries that have a regular hydrogen supply. A great example would be refining and petrochemical industries. We have had, for literally decades, burners designed to burn pure hydrogen, for example, in applications like ethylene crackers.
The fundamentals of hydrogen combustion are very well known. The next evolution that we’re currently in the process of seeing is taking more industries into an availability of hydrogen as a fuel and modifying designs and process heating equipment to accept it. There are fundamentally a lot of changes that occur when you switch the fuel, and we can get into more of those later with more relevant questions, but it doesn’t come without challenges. There is quite a bit to be done, but I think the fundamental science is already well-known. There is a lot of design work to be done and there is a lot of economic and supply development yet to be had.
John Clarke (JC): Yes, I certainly think it is coming, but the timing is uncertain. And, when I say “coming,” I mean deployed in a certain or large volume. When we simply talk about hydrogen, I do think the order of deployment is somewhat predictable and when it comes to pure hydrogen, I think it will likely be deployed first for transportation, and only after that need is met, as a process heating fuel, widely. Now, if there is a breakthrough in battery technology, this order of deployment may change. But, right now, it looks like hydrogen represents an opportunity for higher energy density for long haul transportation. And, if we’re pushing hard to reduce CO2 or carbon emitted, I think policy will be implemented in a means to maximize a reduction of carbon. That’s where I think they’ll be pushing harder.
Now, that said, partial hydrogen, blending hydrogen into natural gas, is likely to occur perhaps sooner than that.
Joachim Wuenning (JW): Not really. I think a lot of things were said correctly and I strongly believe it has to come. If you believe in climate change, it must happen because we cannot use fossil fuels forever. I also don’t believe that we will have an all-electric world. I don’t believe in nuclear power, so we cannot get all our energy from that, therefore, chemical energy carriers will be necessary for storage and long-haul transportation. Is it coming soon? Of course, it is hard to predict how fast it will be. Now, fossil fuel is cheap so it will be hard to compete with as hydrogen is likely to be more expensive.
But certainly, what we see is the requirement from our customers to have hydrogen ready burners. Because, if they invest in equipment at that point, why would they buy a natural gas only burner. They should, of course, look for burners which are able to do the transition without buying all new equipment again. So, we have a lot of projects momentarily to demonstrate the ability of the equipment to run with hydrogen or natural gas and, preferably, not even readjusting the burners if you switch from one to another gas.
Perry Stephens (PS): I’ll try to add something a little different. At EPRI, we’re charged with providing the analysis and data from which other folks, like these gentlemen, are going to try to base important business decisions. Our work hasn’t focused specifically on hydrogen, but, more generally, the class of alternate energy carriers — molecules, gas, or liquid — that can be produced in low carbon first energy ways through renewable energy sources. A lot of our work is focused on understanding the pathways from the initial energy which as a biomass source, solar, wind, could be nuclear, could be hydro. These sources of electric power that ultimately have to be used to produce this low carbon hydrogen. One other pathway is hydrogen or hydrogen-based fuels produce the steam methane reformation process which uses a lot of hydrocarbons but would then require carbon capture and sequestration. The CO2 from these processes could be employed in a circular economy fashion. So, we look at all of these.
The real challenge is the challenge of cost. How do you produce this hydrogen or alternate fuel? And there are many other potential fuel molecular constructs that could be deployed. Ammonia is one being discussed in some sectors. And then how do you transport them, store them, and what is their fuel efficiency and the cost of either new equipment or conversion of existing equipment to deploy those. We’re not specifically focused on hydrogen. It is a very important energy carrier. It can be blended with fossil fuels in the near-term and then maybe expanded in the long term to higher percentages up to pure hydrogen depending on the application, depending on where you produce it. These costs must be evaluated and that is a big job that we’re doing at EPRI with our LCRI initiative right now. We are trying to understand that techno economic analysis, that is, what makes the most sense for each sector of the economy.
Why Not Electricity?
DG: Thanks, guys. Joe had mentioned global warming, a driving force here. Why not electricity? Why don’t we just convert everything over to electricity? Perry, you’re with EPRI, let’s start with you on that. Instead of going just straight-out hydrogen, why not just go to electricity?
PS: I think the question again rephrased might be, “when electricity and when hydrogen” because I think that’s really what we’re trying to decide. There are interesting areas of research involving catalysis techniques that dramatically improve the net energy efficiency of chemical processes, for example, that might make direct electrification of certain processes more competitive. There are electric technologies for the low- to midrange temperatures that are attractive and use pieces of the electromagnet spectrum to produce transformation of products, heating and/or other transformations, that are very cost effective today. So, we judge that a portion, maybe something approaching 30% of the remaining fossil fuel, could be electrified. A certain chunk, a quarter, maybe reduced consumption through energy efficiency, 30% or more through electrification. It’s that difficult-to-electrify piece. Steam-based processes and other direct combustion processes where electric technologies — for one reason or another, don’t look like they offer a strong solution, at least today — that we’re really concerned with. And, both in steam production and direct combustion of fossil fuels today, many cases we’re looking at having to have some sort of alternate combustible fuel.
JC: I’m not sure I completely agree with your question. In some ways, clean hydrogen, or environmentally or low carbon hydrogen, is electricity. It is simply a different means of storing electric power because the source of that is going to be some sort of renewable power, more likely than not, photovoltaics, wind, hydroelectric; those are going to be the electricity we use to break down the water to generate the hydrogen that we then go ahead and store. So, the alternative is whether we use batteries or hydrogen to store this electricity and make it available either in a mobile setting, in a car or a truck, or off-peak times, at times when we are not able to generate electricity from renewables.
I think the question really is more along the line of end use. When are we going to be using electricity for the final end use? We’re kind of process heating guys around this table. I think it’s going to come down to economics, for the most part. And I don’t think we’re quite there yet.
JW: Electricity is fine for some applications. I’ve driven an electric car for the last 10 years, but in long range, I drive the fuel cell hydrogen car from my father, so different technologies for different purposes. There might be batch processes where I can have a break of a week if there is no sunshine and do the batch processing when electricity is available. But if I have a continuous furnace with 100 megawatts which should run 365 days a year, it will be tough to produce the electricity constantly from a renewable basis to fulfill all these requirements. I think it’s just more economic and makes more sense to use the right technology for the right processes. It’s not an either/or. Use the right technology for the right application.
BK: I would just back what Joe says. It can be selective to industry, the furnace type, or the type of material being processed. I know I’ve dealt in my career with a lot of the higher temperature type applications — ceramics and heat treating and things of that nature. If you start getting above 2000 degrees Fahrenheit and up, and especially dealing with airspace, uniformity has a lot to do with it.
Electricity can be hard to get that uniformity without moving fans and having fans that operate at higher temperatures is another challenge. It’s extremely challenging and a big cost factor. What most people have said here is that it is probably not either/or. We see a lot of electricity being used but we’re fossil fuel burner guys, so we’re going to push that efficiency and that kind of cost.
You’re not going to want to miss the rest of this thought-provoking discussion. To watch, listen, or read in its entirety, go to www.heattreattoday.com/2021-09-H2-Reg.
We continue to consider the topic of natural gas pricing and reduction and its impact on heat treaters. Much of the discussion in this month’s article initially appears to deal with process quality or consistency. But understand, process consistency and energy savings are inextricably linked.
This Technical Tuesday column appeared in Heat Treat Today’s December 2021 Medical and Energyprint edition. John Clarke is the technical director at Helios Electric Corporation and has written about combustion related topics throughout 2021 for Heat TreatToday.
In February 2022, we will continue this series. Please forward any questions or suggestions to our editor Karen@heattreattoday.com.
John B. Clarke Technical Director Helios Electric Corporation Source: Helios Electrical Corporation
No matter what method we pursue to save natural gas, it is safe to assume it will require some investment — time and/or materials. Furthermore, we want a payback from this investment. To calculate the payback, we need to estimate the cost of the project as well as the value of the natural gas saved. We can generally nail down the cost of a project by obtaining quotes for materials and labor, but it is more difficult to know what the future cost of natural gas will be; and without knowing the savings, the payback is at best an educated guess.
As we have discussed in previous articles, demand for North American natural gas is increasing for electrical power generation as well as liquified natural gas (LNG) export to areas in the world with limited supplies. These are steady, predictable demands and less susceptible to seasonal variations in temperature. Less heating demand during warmer winters is generally offset by greater electrical power generating demands during warmer summers.
Let us revisit recent trends in the cost of natural gas. The graph below depicts the spot price for 22 consecutive trading days ending November 2, 2021.
Figure 1. Henry Hub price for natural gas
Beware of the displaced origin on the graph below — it makes the fluctuations in the spot price appear greater than they are, but it is done to indicate a range of prices — generally around $5.50/mmBTU. (Once again, neither the author nor Heat TreatToday presents the opinion of future prices for any purpose other than to further our discussions of energy saving project paybacks.)
Last month, we posed three questions:
How do I know when the material I am heating is at the desired temperature?
Do I have excessive factors of safety built into my process to compensate for not knowing the temperature at the core of the part being heated?
How much fuel can I save with a shorter cycle?
Much of the discussion in this month’s article initially appears to deal with process quality or consistency. But understand, process consistency and energy savings are inextricably linked.
What temperature is my furnace or oven?
You walk up to the controls and read 1650°F. Is that the temperature of your oven? The answer is a definite “maybe” because the temperature displayed on a single loop temperature controller is simply the reflection of the small voltage generated by one thermocouple. This is obvious, or else we wouldn’t need to run temperature surveys. But the question is — do we have to live with this shortcoming? The answer to this question is a definite “no”! Modern control instrumentation makes it easy to use many thermocouples to sense the temperature of the furnace throughout the chamber. Then take the mean of these values to calculate the temperature and use this average value for the input to our temperature control loop. By comparing the readings of temperatures at various points in the furnace chamber, we can sense if all the work being heated is near to the desired setpoint.
No furnace load is perfect — there is always some non-uniformity of mass or surface area. With multiple sensing points, the more massive and slower to heat portion of the load will influence the nearest thermocouple. The furnace control can be designed to hold until the coolest thermocouple in the chamber reaches some minimum temperature. Perhaps this is now the trigger for a soak timer.
In addition to measuring multiple chamber temperatures and inferring the actual temperature of the work, the proportional integral derivative, or PID, temperature control algorithm provides a good deal of insight as to how close the work is to the desired furnace temperature. All PID controllers or programmed functions provide an output value. For our discussions, we will assume the output is between 0-100%. This output is used to control the heating element(s) of burners’ input levels. The advantage of the PID loop is that it calculates the required value more rapidly than a conventional on/off control — providing us the near steady values for our furnace temperatures.
Let’s imagine we adjust the temperature setpoint of our empty furnace to 1650°F. We will allow it to come to temperature and wait an hour until it is soaked out, so that the refractory and internal components are at some steady state temperature. The PID loop will settle to some average value; we will assume this value is 35%, which represents the holding consumption of the furnace. The heat entering the furnace is in equilibrium with the heat being lost through the refractory, up the flue, around the door, etc.
Now we load the furnace with 4000 pounds of thick steel parts, where the mass/surface area ratio is very high. The furnace thermocouple(s) will reach 1650°F in one hour; but, if we look at the PID loop output, it will take time for it to fall to 35%. The time between the indicated 1650°F and the output falling to 35% is a period when the work continues to absorb heat and conduct it to its core. When the output stabilizes at 35%, we know the work is soaked out at temperature — in other words, the surface and core of the parts are at the furnace setpoint temperature.
Do I have excessive factors of safety built into my process to compensate for not knowing the temperature at the core of the part being heated?
With added insight into the actual temperature of the work being heated, excessive soak times can be reduced without risk. It also allows for the running of light and heavy loads with the same program.
How much fuel can I save with a shorter cycle?
Building on the same hypothetical; assume the input to this furnace is 4,000,000 BTU/Hr and 1,000 hours are saved per year — the savings will be roughly 4,000,000 BTU/Hr x 0.35 (holding consumption) x $5.50/mmBTU x 1,000 Hours per year, or $7,700/year. Now, perform this modification on four furnaces. Add to this savings the increased confidence that the work is at temperature before the soak period is initiated, better consistency for varying part loading, and I think we can agree — we have a project. The only question is, will we cash the check?
About the Author:
John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.
Since February 2021, Heat Treat Today has had the privilege of publishing the Combustion Corner. In each of these columns, John Clarke, technical director at Helios Electric Corporation, shares his expertise on all things combustion. In this Technical Tuesday, we're taking a moment to review more of the key points from John's columns. As always, we hope this review helps you to be more well informed, and to make better decisions and be happier. Enjoy these five summaries of the second half of the Combustion Corner columns. To view each installment, click the blue heading below. 
Process consistency and energy savings are inextricably linked. To lower operating costs and increase process consistency, John Clarke suggests asking three questions: What temperature is my furnace or oven, really? Do I have excessive safety factors built into my process to compensate for not knowing the temperature at the core of the part being heat treated? How much fuel can I save with a shorter cycle?
In this installment of the Combustion Corner, John Clarke takes some time to reassure the heat treating industry of two key facts about the United States' natural gas market:
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