Last month we began the discussion about the relationship between combustion safety and uptime, highlighting how combustion safety, reliability, emissions, and efficiency are inseparable. This month, we will explore the subject in greater detail and outline a path that can both reduce the risk of an incident and protect the bottom line.
This article written by John Clarke, technical director at Helios Electric Corporation, appears in the annual Heat TreatToday 2021 Buyer's Guide June print edition. Return to our digital editions archive on Monday June 21, 2021 to access the entire print edition online!
John B. Clarke Technical Director Helios Electrical Corporation Source: Helios Electrical Corporation
How many times have we heard the tale about the man with the leaky roof? He cannot fix his roof when it is raining, and the roof doesn’t need repaired when it is not. This story is also applicable to heating system maintenance, perhaps more so than other plant maintenance activities because it so seldom “rains.” Ovens and boilers tend to be very reliable. (This statement is true for equipment operating at low or moderate temperatures, less so for equipment operating above 1832°F (1000°C).) It is exactly when the machine is properly producing parts that the planning for combustion safety, availability, and performance must occur.
The first critical step we must take is to understand that combustion safety, routine maintenance, tuning, and calibration are parts of a larger work strategy. To focus solely on the annual inspection of safety components while ignoring system tuning will not only compromise tuning and efficiency, but also the safety. We have seen how managerial reactions to high profile incidents have caused some firms to dispatch teams to annually examine valves and pressure switches. This effort is highly compromised if it does not include all aspects of system maintenance as well as capturing what is learned each time to improve future inspections and equipment designs. There is data beyond pass and fail that is valuable if we wish to optimize the performance of our equipment
Let us assume it is a clear sunny day, and we are ready to invest some time in preparing to improve our combustion system starting with a deep dive examination of two pressure switches: the low fuel gas pressure switch (LFGPS) and high fuel gas pressure switch (HFGPS). These ubiquitous components are present on nearly every fuel train and are vital for safe operation. As their names imply, they monitor the fuel pressure and shut the safety valves if the fuel gas pressure is either too high or too low.
These switches must be listed for the service they provide by an agency independent of the manufacturer – UL, TUV, FM, etc. Simply looking for a stamp may not be enough; take the time to read the file or standard being applied by the agency and determine if it describes the application. Next, ask if the pressure switch carries the basic ratings expected, like the enclosure rating (Nema or IP). Is a Nema 1 switch operating in a Nema 12 area? Temperature ratings must be confirmed. All too often a component rated for 32°F (0°C) is applied in an outdoor environment in cold climates, or one with a maximum rating of 120°F (50°C) is applied next to the hot wall of a furnace. The component may operate out of specified environmental ranges for some time, but to apply a component in this manner is betting against the house – sooner are later we are going to lose. Ask the people of Texas if the bet against sustained cold temperatures in early 2021 was worth it.
"John Clarke, Technical Director, Helios Electrical The first critical step we must take is to understand that combustion safety, routine maintenance, tuning, and calibration are parts of a larger work strategy"
Next, let us look at the contact(s) rating of the switch and how it is applied to the burner management circuit. More often than not, these switches are in control circuits fused for more current than the contact rating. If the switch rating is too low, the electrical designer has an option to use an interposing relay to increase the current carrying capacity to this device. This relay is an added component, and as such, adds yet another possible point of failure. If the relay is interposed, is it dedicated to this one switch? Multiple devices being interposed by a single relay is prohibited by NFPA 86, for good reason. Is the relay designed to fail safely? That is, will a relay coil burn out or wiring fault close the critical safety valves? Is the wire gauge suitable for the current carried and protection device used?
Next, is the switch mounted in a safe location free from possible vibration or the foot of an eager furnace operator? If the switch must be changed, are clearances provided to perform this maintenance? What is the mean time to replace (MTTR) the component? Is the way the device is wired providing a path for combustible gas to enter the control enclosure and cause an explosion? Flexible conduit, without a means to seal the connection, is a very common error. Use a properly specified cord and consider using some type of connector to terminate the wiring at the switch. A simple 7/8-16 or DIN connector not only provides additional protection from combustion gas getting into the electrical conduit but is also a great benefit when changing the component in a rush and helps to isolate the component’s control circuit during testing and calibration.
Is the pressure switch suitably protected from bad “actors” in the fuel gas? Perhaps soot is present that could foul narrow passages or H2S that could result in corrosion. These are rare conditions, but coke oven gas may not be as clean as purchased natural gas. Do we need to specify stainless steel components? Would a filter make sense to protect the switch and increase the intervals between maintenance?
Finally, let’s discuss pressure ratings. Unfortunately, nomenclature varies by manufacturer. What is the maximum pressure the device can sustain and not fail, i.e., leak fuel gas into the environment? Many switches can experience a pressure surge without risk of leakage, but the high-pressure event will damage the switch internally. It is important when determining if this rating is adequate to consider possible failure modes that might expose the pressure switch to excessive pressure. As a rule of thumb, a pressure switch must be able to sustain a surge pressure delivered to the inlet of the pressure reducing regulator immediately upstream of the device. Think of it this way, if the upstream regulator experiences a failure, the full pressure delivered to this regulator will pass to the pressure switch in question.
Other obvious pressure ratings are the maximum and minimum set points. The pressure switch should be set to trip as close to the middle of the range as possible and should never be set close to either the minimum or maximum setpoint. Is the pressure switch manually or automatically reset after a trip? In general, it is best practice that the LFGPS resets automatically, and the HFGPS requires a reset by the operator. This recommendation is because LFGPS trips each time pressure is removed from the system, and it is generally understood that the system needs fuel to operate. On the other hand, a high-pressure event is exceedingly rare, and the operator should be made aware of this unusual event.
This article has discussed a lot about the simple pressure switch. It appears to be a heavy lift to perform this analysis on every pressure switch in a facility, but take comfort, once the exercise has been completed on the first system, it is much easier to replicate what has been learned to properly assess other systems. We should most definitely insist that our OEM provides this data, in detail, when new equipment is supplied. Why did we review all these specifications? Because I have been around for a while and have seen nearly every one of these errors in the application of pressure switches on operating combustion equipment.
Next month, we will expand on the pressure switch discussion to describe the tune/calibration and testing processes. I hope this deep and specific dive has been of value. If you have any questions or comments, please let me know.
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.
Excess air plays multiple roles in heat treating systems. Learn about its importance in combustion and heat transfer, and why being well-informed will help your system run at peak performance.
This original content article, written by John Clarke, technical director at Helios Electric Corporation, appeared in Heat TreatToday’s Aerospace March 2021 print magazine. See this issue and others here.
John B. Clarke Technical Director Helios Electric Corporation Source: Helios Electric Corporation
Is your system running optimally? The following discussion will provide a better, albeit abbreviated, understanding of the role of air in combustion and heat transfer.
Excess air in heating systems plays many roles: it provides adequate oxygen to prevent the formation of CO or soot, can reduce formation of NOx, increases the mass flow in convective furnaces to improve temperature uniformity, and at times, wastes energy. Excess air is neither good nor bad, but it is frequently necessary.
To begin, we must first look at a basic formula. For our discussions, we will replace natural gas, which is a mix of hydrocarbons with methane (CH4). The oxygen (O2) is supplied by air.
The above simplified formula describes perfect or stoichiometric combustion. The inputs are methane and air (where only the O2 is used to oxidize the carbon and hydrogen in the methane), and the products of combustion (POC) consist of heated carbon dioxide (CO2), water vapor (H2O) and of course nitrogen (N2). (The actual reaction is far more complex and there are other elements present in air that we are ignoring for simplicity.) As we can see from the equation, the oxygen we need to burn the methane comes with a significant quantity of nitrogen.
In practice, it is very difficult to even approach this stoichiometric or perfect reaction because it would require perfect mixing, meaning that each molecule of methane is next to an oxygen molecule at just the right time. Without some excess air, we would expect some carbon monoxide and/or soot to be formed. Excess air is generally defined as the percent of total air supplied that is more than what is required for stoichiometric or perfect combustion. For natural gas, a good rule of thumb is to have about 10 cubic feet of air for every one cubic foot of fuel gas for perfect combustion. Higher air/fuel ratios, say 11:1, are another way of describing excess air.
In most heating applications, the creation of carbon monoxide and other unburnt hydrocarbons should be avoided, except in the rare cases where they serve to protect the material being processed. Employees must be protected from CO exposure; and soot can damage not only equipment, but the material being processed.
Source: Heat Treat Today
The amount of excess air that is required to find and combine with the methane is dependent not only on the burner, but also on the application and operating temperature as well. Some burners and systems can run with very little excess air (under 5%) and not form soot or CO. Others may require 15% or more to burn cleanly. Just because a burner performs well at 10% excess air in application A, does not necessarily mean the same level is adequate in application B.
Once the quantity of air exceeds what is needed to fully oxidize or burn the methane, combustion efficiency will fall because the added air contributes no useful O2 to the combustion process, and it must be heated. It is very much like someone putting a rock in your backpack before you set out for a 16-mile trek. Taking this analogy further, higher process temperatures equate to climbing a hill or mountain with that same rock — the higher the climb, or the higher the process temperature, the more energy you waste. Sometimes this added weight or mass can be useful.
The higher the excess air, the greater the mass flow. In other words, the total weight of the products of combustion goes up, and the temperature of the CO2, H2O, N2, and O2 goes down. If we are trying to transfer the heat convectively, this added mass or weight will provide improved heat transfer and temperature uniformity. A simple way to think of temperature uniformity is that the lower the temperature drop between the products of combustion and the material being heated, the better the temperature uniformity. Many heating systems are specifically designed to take advantage of this condition – higher levels of air at lower temperatures. This is especially true when convective heat transfer is the dominant means of moving heat from the POC to the material being heated (when the process temperature is roughly 1000°F or lower).
Source: Heat Treat Today
Some heating systems are specifically designed to operate as close to perfect combustion as is possible as the material is heated then switch to higher levels of excess air to increase the temperature uniformity as the setpoint temperature is approached. In other words, it provides efficient combustion when temperature uniformity is less of an issue and a very uniform environment as the material being processed nears its final setpoint temperature.
Of course, a system can be supplied with too much air, which can waste energy, but also prevent the system from ever reaching its setpoint temperature. The energy is insufficient to heat all the air, the material being processed, and compensate for furnace or oven loses. In these instances, it is obvious that we must reduce the air supplied to the system.
In indirect heating systems – where the products of combustion do not come in contact with the material being processed, like radiant tubes, for example — air in excess of what is required for clean combustion provides limited benefit and should generally be avoided. In these systems, it is best to play a game of limbo, “How Low Can You Go,” so to speak. Test each burner to see how much excess air is required to burn clean and add a little bit for safety. Remember, if you source your combustion air from outside in an area with significant seasonal variations, the blower efficiency will change, and seasonal combustion tuning is required.
Lastly, some burners require a minimum level of excess air to operate properly. This additional air prevents critical parts of the burner from overheating – or the air may limit the formation of oxides of nitrogen (NOx). In this application, altering the burner air/fuel ratio could generate excessive pollutants or even destroy the burner.
Efficiency is important, but the process is king. There is no magical air-to-fuel ratio and no single optimum level of excess air in the products of combustion. Each application is unique and must be thoughtfully analyzed before we can confidently say we have optimized our level of excess air. But careful attention paid to the effect that excess air has on your fuel-fired systems will pay dividends in improved safety and efficiency.
About the Author:
John Clarke, technical director at Helios Electric Corporation, a combustion consultancy, will be sharing his expertise as he navigates us through all things energy as it relates to heat treating equipment.
Natural gas. It’s a necessity for producing energy and a staple in the heat treating industry. In this reader-friendly and thorough guide of all things natural gas, learn about its supply and demand, availability, pricing, consumption and much more.
This column will appear in Heat Treat Today’s2021 Atmosphere-Air February print edition.
Heat Treat Today is pleased to announce that John Clarke, technical director at Helios Electric Corporation, will be writing about combustion related topics throughout 2021. John has been a long-time friend of Heat Treat Today and his expertise in system efficiency analysis, burner design as well as burner management systems will be incredibly helpful as he navigates us through all things energy as it relates to heat treating equipment.
John B. Clarke Technical Director Helios Electrical Corporation
This article is the first in a series describing trends in energy use and technology used in heat treating equipment. So, it is important to first discuss the supply and demand for natural gas–the energy source on which we depend for not only combustion for heating, but also to generate a substantial share of our electricity.
Heat treaters, be they captive or commercial, are dependent on natural gas to power their operations. Its price and availability are areas deserving special attention from anyone responsible for the purchase, maintenance, and operation of heat-treating equipment.
The good news is that the sky is not falling. In fact, it is a pleasant and sunny day, figuratively speaking. The bad news is that we are increasingly dependent on this one energy source. The economic impact from rapid spikes in cost will be even more severe than they were in the 2005-2009 period, when the United State saw prices for natural gas double in just a few days.
Natural gas production in the U.S. has effectively doubled in the last 15 years (US Monthly dry natural gas production has moved approximately 1.5 trillion cubic feet in 2005 to nearly 3.0 trillion cubic feet.),1 while the average price has fallen 50%.2 (Average Citygate Price–cost as the fuel is transferred from the pipeline company to the local distribution company– has fallen from around $8.00 USD/mmBTU to less than $ 4.00/mmBTU.)2 It seems that the economics professors were right – as supply expands, prices fall. And these prices have been remarkably stable.
But wait: “Danger, Mr. Robinson” (Imagine a robot with vacuum cleaner hoses for arms shouting a warning to all of us). Is it really that simple? Can I invest my resources with confidence that the price for my energy will remain constant? Should I hedge my bets by spending more on increased efficiency? What is the impact on my return on investment? Can I count on the availability of this energy source? Critical questions all, and questions we will address in this and subsequent articles.
What is Natural Gas?
Natural gas is a mix of a number of hydrocarbons with 80 to more than 90% methane (CH4) and lesser quantities of ethane(C2H6), propane(C3H8), heavier hydrocarbons, carbon dioxide (CO2) and/or nitrogen(N2). The composition varies depending on the source, but it averages a higher heating value (HHV) of around 1,000 British thermal units (BTU) per standard cubic foot (SCF). This fuel can be used directly to heat our equipment and is being used, in increasing quantities, to generate our electricity.
Domestic Production
Advances in horizontal drilling and hydraulic fracturing (fracking) have greatly expanded our domestic production of both oil and natural gas, releasing otherwise “tight” gas and oil previously trapped in shale formations. This has made recovering these sources of natural gas economically feasible. The supply of shale natural gas grew sevenfold in the last 15 years and now represents roughly two-thirds of our total domestic production of gas. (2005 shale gas production was less than 10 billion cubic feet per day to over 70 billion by 2020.)3 Furthermore, the Energy Information Agency (EIA) — an agency within the Department of Energy charged with tracking US energy production, consumption, and project future demand and supply– projects an increase in US domestic production through at least the year 2050.
Domestic Consumption
Natural Gas Use by Sectors in the US, 2019 and Change Since 20094
Total Consumption 2019 31 Trillion Cubic Feet
Total Consumption 2009 23 Trillion Cubic Feet
Efforts to reduce CO2 emissions from electrical power generation and reduce the cost of new generating capacity have led to a rapid expansion of electricity generated using our abundant supply of domestic natural gas. Switching from coal to natural gas reduces CO2 emissions by nearly 59% per unit of electricity generated. (See table “U.S. electric utility and independent power… by fuel 2019”)5Noteworthy Trend – Electrical Power Generation
In the last 10 years, coal consumption for electricity generation has fallen 48% while natural gas’s contribution has gone up 60%.6 This investment in new natural gas fired electrical generating facilities has created a very stable demand. It is likely that this trend will continue as coal plants are shuttered in favor of the cheaper and cleaner natural gas alternative. In the long run, renewables, specifically solar and wind, may displace some of this natural gas consumption, but in the near term, coal is the most likely fuel to be displaced. The demand for electricity produced by natural gas will be buoyed further by the rapid expansion in the use of electric vehicles.
Exports – Liquified Natural Gas (LNG)
The US was a net exporter of LNG in 2017 and 2019. Our export capacity has expanded nine-fold from 2016 to 2019, growing from 0.36 trillion cubic feet per year in 2016 to 3.24 trillion cubic feet per year in 2019. As our capacity to export natural gas expands, it is likely that an increase in international demand will place upward pressure on domestic prices.
Externalities – The Unpredictable
There are factors that are, by their very nature, impossible to quantify. They remain a risk, nonetheless. As political power shifts in Washington, it is likely that politicians will pursue legislation to reduce CO2 emissions. The Biden administration, for example, could seek to reduce coal consumption by switching to natural gas as a means to generate electricity. Regulations or moratoriums on fracking might reduce our ability to expand production in the face of rising demand. The U.S. may seek to export more natural gas to reduce allies’ dependency on natural gas produced by our geopolitical rivals. On balance, the net effect of these political factors cannot be predicted and modeled with any certainty.
Other non-political factors make our future less clear. Weather remains a constant unknown and as natural gas’s share of electrical generation expands, both hot and cold weather can lead to an increase in demand. Furthermore, excessive speculation could also introduce instability to prices if not supply. Remember Enron and the effect on electrical power prices and supply in California in 2000 and 2001.
Conclusion
With any luck, we will see no national supply or demand shocks that will imperil the availability of natural gas for U..S industry. I am concerned that prices will rise and fluctuate as a result of one or more of the factors highlighted in this article. These risks should be considered when making equipment acquisition, maintenance, and operating decisions. In the upcoming articles, we will focus on technologies and practices that can help to mitigate these risks as well as save both energy and money.
[5] “FREQUENTLY ASKED QUESTIONS (FAQS): How much carbon dioxide is produced per kilowatthour of U.S. electricity generation?” Independent Statistics & Analysis U.S. Energy Information Association.https://www.eia.gov/tools/faqs/faq.php?id=74&t=11.
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.
Welcome toHeat Treat Today'sThis Week in Heat TreatSocial Media. As you know, there is so much content available on the web that it’s next to impossible to sift through all of the articles and posts that flood our inboxes and notifications on a daily basis. So, Heat Treat Todayis here to bring you the latest in compelling, inspiring, and entertaining heat treat news from the different social media venues that you’ve just got to see and read!
Check out what heat treating 3D parts does to the integrity of this aluminum piece. Join the discussion in the thread below to see what makes the difference: proper printing or proper heat treatment.
2. Getting Social Online
Let's not talk about the you-know-what that is causing reverberating changes throughout the world. Suffice it to say, many are looking for ways to network, meet, work, and, well, live at a distance. Here are some ways that social media has helped people in the heat treat industry draw people together.
Family Day
Figuring out how to be keep the momentum going at your plant or manufacturing facility may be a challenge, but NitrexMexico seems to have the right idea in (a) recognizing the whole life that their employees have, and (b) throwing a special celebration virtually.
Not wanting to miss out on FAMILY DAY, Nitrex Mexico treated employees & families to a home-delivered catered meal. According to Nayelly Torres, HR Coordinator, the event was created 3 yrs ago to recognize the important role family plays in empowering us to be the best we can be. pic.twitter.com/EbAARvDJgo
Recognition isn't just internal. Focusing on missions outside of one's own life has the interesting effect of drawing people together. See SECO/WARWICK's participation in an endeavor to do just that.
?We do pushups for a little boy named Kajetan, accepting the #GaszynChallenge.? ?
We always put our best endeavors to do more, so we DOUBLED the bet #donating 10 pln for each "pushinguping person" ‼️
These media shared online commemorate the recent past of the heat treat industry. The industry was very different - forget how everyone lived in black and white!! - but also still the same. Check out the media below to get glimpse of the times 50 to 75 years ago.
Geeking Out Over 1945 Aluminum Heat Treat Footage
This YouTube video is an educational film released in the last year of World War II (to give you a context reference) for the heat treatment of aluminum. You can find part 2 by going to this YouTuber's channel.
Bodycote Induction Heating from 1945
What procedures can you see in this picture from an induction heating plant from 1945? Any regulations or plant layout changes as compared to today's?
A "Game Changer" from the 70's
Think about what makes a game changer. This car bottom furnace most certainly qualified as such in 1977, using the most cutting edge technology of its time. Like John Hubbard's sister, there may be something worth sharing in the forgotten news of the past.
4. Reading and Podcast Corner
Ever wanted to have access to resources for on the job training? Read or listen to the sources below to learn a new technique, tip, or other aspect of the industry.
The Future of Heat Treat and the Environment
Center for Heat Treating Excellence
Being a manufacturer with in-house heat treating requires awareness to innovation, and the Center for Heat Treating Excellence is a cooperative membership that keeps you on the cutting edge. Listen to the projects and mission of CHTE in the podcast.
All combustion is not created equal. Listen to Carl Nicolia explain how small changes to your furnace administration can result in high value solutions.
What will Conferences Look Like in the Future?
With protocols and general modes of holding conferences changing over this year, Thomas Report provides an insightful look at how these changes may affect how conferences are conducted in a post-COVID world. Check out the list in this article; maybe you yourself have already thought of one or two of these.
5. Heat Treat Hashtags
Stay current with the latest posts by using these heat treat related hashtags. When you post something on LinkedIn, Twitter, or Facebook, help people find you by using the hashtag that works for you, and @HeatTreatToday so that we can see it too!
#MetalMonday
While many manufacturers and suppliers of heat treatment products have used this hashtag over the years, the most prolific user at this time is Bodycote.
#ManufacturingMonday
Looking for a useful hashtag? This one is a practical add-on which alerts to quite a few tips in the industry.
This one is very similar to #MetalMonday, but it is not as streamlined. Check it out and see what you can find on Twitter, LinkedIn, or Facebook!
#Mfg
Another general hashtag, you never know what you will find, whether it be a fringe development or cutting edge new safety measure. @HeatTreatToday if you find anything worth sharing!
#heattreating
Of course, this hashtag exists! The next time you share a post or post something yourself, be sure to use the hashtag to increase your views!
Welcome to another episode of Heat Treat Radio, a periodic podcast where Heat Treat Radio host, Doug Glenn, discusses cutting-edge topics with industry-leading personalities. Below, you can either listen to the podcast by clicking on the audio play button, or you can read an edited version of the transcript. To see a complete list of other Heat Treat Radio episodes, click here.
In this conversation, Heat Treat Radio host, Doug Glenn, interviews Carl Nicolia, President of PSNergy, to learn about how applying efficient combustion can drastically improve the performance of your machines. Click below to hear about high value solutions and where we stand in the "evolution" of combustive techniques.
The following transcript has been edited for your reading enjoyment.
DougGlenn (DG): Today's topic is combustion. It is not only an important feature, but also the core to heat treat as the key to high value solutions; that is, according to today's guest, Carl Nicolia (CN), the president of PSNergy. Carl wrote an article that appeared in a recent edition of Heat TreatToday entitled, The Science of Combustion in an Era of Uncertainty. Several of the points Carl dealt with in that article, we'll deal with today. Get ready to read why not all fire is created equal and why your company needs to evolve with the times and take advantage of the recent combustion efficiency technologies.
First page of Carl Nicolia's article from the June Automotive Issue, The Science of Combustion in an Era of Uncertainty: Darwin was right...Evolve or Perish.
DG: Carl, tell us about your background.
CN: I had a great career in larger global businesses - folks like GE and Chrysler Corporation. After that run, I had met several very smart people that had been in the combustion industry for some time and they had some unique ideas on how we could really truly help elevate the performance of heat treating operations. After doing some homework on the industry, the technology, and the opportunity there, we started PSNergy in May of 2013. Since then, we have been helping customers, really throughout North America, solve combustion issues and help deliver productivity to combustion operations. We are primarily focused on radiant tube combustion systems. We do some open fire work as well. The team itself brings over 40 years of combustion experience to the table. We were really formed on innovation around the fundamental sciences, mostly physics and heat treat, and with a huge obsession for customer satisfaction. We really like to take the approach of becoming part of the customer's team, not really being considered an outside resource, but more of a team member with them, and really develop and play for the long term. That's the background on how we got into the combustion industry.
DG: The immediate reason for us talking with you today is because in our June 2020 issue, on page 37, we had a very interesting article or column written by yourself entitled The Science of Combustion in an Era of Uncertainty: Darwin was right, Evolve or Perish. That was the name of the column. A little bit provocative and an interesting column. And, for those who might be reading this at a later point, we are on the, I want to say, the tail end of a Covid-19 pandemic, but some people might say we're in the middle of it. Nonetheless, that's why the article says, “in an era of uncertainty.” I want to talk to you a little about that column. You make this comment in there, and there are a couple of comments I want to ask you about, and then we'll move on to the more substantive stuff. You say, “All fire is not created equal.” This is an interesting comment. What did you mean by that?
CN: Our team has been having a lot of fun with the caveman references and the whole concept of evolution and when we thought about it, it really did apply well, especially in today's times. We won't get into whether we're at the beginning, middle or end of the Covid thing, but thinking about going from fire at the end of a club to modern combustion systems is a huge leap forward. It was a good way for us to think about and highlight the concept that all fire is not created equal. Just because the burners are firing and the furnace is hot, doesn't mean that you're burning efficiently. There is a big difference between well-tuned, well-balanced combustion systems, and not well-tuned and well-balanced. So in that reference, we talk about setting combustion appropriately: getting the right air/fuel ratio can mean the difference between, in a heat treater's case, profitability and loss or high quality and scrap. Balancing that combustion across the entire system can mean the difference in getting customers and providing the turnaround times that they need. Getting that combustion system balanced and tuned, and keeping that system balanced and tuned, are really essential to “getting the most out of your fire,” if you will. So we had some fun with that reference. You will see that carry through some our advertising in the months to come, as well.
(photo source: PSNergy)
DG: You make one other reference to Charles Darwin and a quote that he mentioned. The quote is not all that brief, but I wanted you to comment on it, if you could. It says “It is not the strongest of the species that survive, nor the most intelligent that survive. It's the one that is most adaptable to change. Intelligence is based on how efficient a species became at doing the things they need to survive.”
CN: That's a great quote, and again, we're having a little bit of fun with it, but especially in today's world. I know that many of your readers have been in operation for generations and those companies have found a way to get a little better, a little smarter, every day, every year, and have not gone through Covid-19, but I'm sure other different issues. I think having them focus on what's critical, really making smart investments, these are the type of things that help move their operations forward, help evolve their operation. That's the type of evolution we're talking about.
Evolution to us is small, impactful changes that make a big difference. Although today it might be difficult to imagine, end customers in automotive, construction, and off-highway vehicles are going to be back. And there is going to be pent-up demand. Productivity is going to be an issue in the months ahead. Our end customers, as they come back online and look for suppliers that can meet that rate with high quality and responsiveness, that's going to be a differentiator. And so, we think that thinking about that evolution now is really important. Making the changes now while you can and be responsive when the time comes, is the right move for us; that's the evolutionary piece.
DG: PSNergy, as you've already mentioned, really focuses in on combustion, combustion efficiency, furnace efficiency and that type of thing. On the second page of this article (page 38 in the June 2020 issue), you mention a case study in there where your crew went in and helped a contract commercial heat treater to improve some efficiency. Can you run down through that case study quickly and tell us what you guys were able to do to help them adapt and improve the type of fire they had in their organization?
CN: Sure. And this is a great story, but it is not a unique story for us. We have quite a few of these success stories around our products and services. We had a Midwest contract heat treating company that was interested in the ceramic waste heat recovery inserts. These are patented devices that we design here at PSNergy. They go into the exhaust leg of the radiant tube and they capture that energy that is normally lost out the exhaust, keeping that energy inside the furnace. In the process, it balances the tube temperature and really increases the productivity of the process.
[blocktext align="left"]Their recovery cycle was reduced by 25% ... And in that total cycle, they dropped gas consumption 5% which eventually led to an increase in output of that furnace by 10% ... the total cost to implement this was less than $10,000.[/blocktext]So, in this particular example, it was a 9-ft IQ furnace and it had four U-tubes, probably a pretty typical type of furnace that we might see in a lot of the contract heat treating manufacturers, like your audience. What we did was install inserts in the exhaust legs of the four tubes and then balanced and tuned the system. This entire process took less than one 8-hour shift to finish. As you can see, the results were really impressive. I always like to say at this point, this is not our data, this is customer data. Their recovery cycle was reduced by 25%. Now, a recovery cycle is from the time I close the door to the time I start my controlled cycle. 25% reduction. And in that total cycle, they dropped gas consumption 5% which eventually led to an increase in output of that furnace by 10%. What we love about this, and this is kind of the theme of the article really, is that the total cost to implement this was less than $10,000. This is a perfect example of high value solution. I hate to say 'low cost' because cost is relative, but this is high value. If I can deliver 25% improvement with less than $10,000, or if I can deliver 10% double-digit output increases for less than $10,000, that's a high value solution.
DG: At $2500/tube, and you had four tubes you were 'upgrading,' if you will, that's pretty impressive.
CN: The beauty of this was there were no piping changes, no construction, and no long downtime. By using the patented technology, the new technology that's out there, combined with our tech-enabled services (balancing and tuning), again using the latest in sensing technology and cloud computing, this customer was able to achieve significant performance improvement. What's awesome is that this is a pretty common story for us. When we do this, these are the types of numbers we can achieve.
DG: We kind of skimmed over a little bit about the inserts. Let’s take just a minute and make clear what exactly you're providing as far as the inserts primarily, and the services as well.
CN: The radiant tube inserts, we like to call them ceramic waste heat recovery devices or waste heat recovery inserts, are primarily silicon carbide and they are in a patented configuration that provides significant improvement in delivering energy through the tube into the load. And they do that by being the right material, (silicon carbide has a very high emissivity, having the right shape, where we take advantage of radiant energy transfer to the tube because of the shape of the insert, and having a wide open cross-section which does not put a lot of back pressure on the combustion system; we allow the combustion system to breathe. Inserts have been around for a long time. The big technology improvement here is having the right material and having it in the right configuration to maximize the amount of energy that is delivered in a radiant tube and minimize the effect on the combustion system.
DG: And are these inserts only for U-tubes?
CN: No, they can be applied on any radiant tube. We've applied them on straight tubes (or I-tubes), U-tubes, Trident® tubes, and W-tubes.
DG: You talk in the article about combustion efficiency and furnace efficiency. Can you elaborate on that and the difference between the two?
CN: We think about this relatively broadly. Combustion efficiency is getting the most energy out of the fuel you purchase, and ensure that you continue to get that same level of performance. This is happening at the combustion system level, the burners, if you will. This goes back to achieving optimal air/fuel ratios. And it is so important, yet often overlooked by a lot of people. The difference between 7% excess oxygen in the exhaust and 3% excess oxygen is significant. If you're at 7% excess oxygen, you're delivering 20% less energy to the furnace than you are at 3%. 20% is a huge, huge number. Especially when you're talking about the core process for heat treating operations, making heat. I think often times we forget that in heat treating, combustion is the core process. Anytime we're running through a heat treat operation, you have to have optimal combustion. And there are high value, easily implemented solutions out there that help you maintain and achieve the optimum combustion.
When we think about furnace efficiency, furnace efficiency is what our customers get paid for - getting energy from the combustion system to the product. And how well we do that, in our view, is furnace efficiency. Think about it this way: You could have a perfectly balanced and tuned combustion system (those four tubes on our example furnace can be tuned perfectly), but we can let, in that system, 40% of the energy escape out of the exhaust. So combustion efficiency might be high, but furnace efficiency is not optimal. That's where we think about implementing the ceramic waste heat recovery devices, for example. You could talk about textured tubes or bubble tubes as another example to help you get that energy from the combustion system into the load. Getting more of the energy produced in efficient combustion for that product being processed – that's the name of the game, and that's furnace efficiency as we see it.
DG: You and I were talking about a recent report that came out from ArcelorMittal regarding their “green movement.” Can you recap that, and maybe hit on the ability for small companies to also embrace the technology that some of these bigger companies are able to embrace?
CN: We found this very informative. ArcelorMittal issued their 2019 “integrated report,” where they discuss their corporate responsibility and sustainability initiatives in the US. They have ten sustainability development outcomes, and energy management is one of those ten key outcomes. ArcelorMittal highlighted the development of a low-cost oxygen sensor for furnaces that reduce fuel consumption by allowing plants to see that combustion performance and then tune for optimization. This goes back to our discussion: Furnace combustion performance is the core to these operations, and they're highlighting the value of getting combustion balanced and tuned correctly and keeping it correct.
Not everyone listening and reading, I'm sure, has the resources of ArcelorMittal, so luckily, PSNergy has developed this technology for everyday heat treating operations and any one of us can now apply this. In fact, the same leading edge sensing technology and cloud computing technology is what our service team uses to deliver our combustion engineering services, or balance and tuning, and that is also incorporated into our combustion monitoring and alerting system. We like to call that CMA. And installing CMA on your furnace is like having a dedicated technician taking combustion measurements every day. If something is starting to go out of tune, actions can be taken immediately before furnace performance is affected and alerts can be sent through the system. Daily reports are issued on combustion and so you know combustion is running well. And if it's not, you're deploying resources to get that out.
DG: So this combustion monitoring and alerting system is a cloud-based system?
CN: Yes, it is, but fundamentally, it is a sensor. It's oxygen monitoring and pressure monitoring that is installed on each individual tube of the furnace that records excess oxygen in the stack just as if you would stand there as a technician with a handheld meter, but this is all connected through the cloud which allows it to be accessible, which allows it to store the data for future trend analysis. We've been able to use that tool to identify failing motorized control valves, declining performance on combustion air fans, etc. There is so much that you can see over and above when you're starting to look at data over time versus a single point in time and that's where the cloud piece comes in. It starts with pulling the sample from the right spot in situ from the exhaust and having the highest level of sensing technology available on the oxygen side and then sending all of that up to the cloud for the analysis for the reporting. It basically is a tech standing there taking measurements every day and then you're able to then get a report that says this is where our combustion is, and I can take steps to do that.
DG: I've got a question about that. So you've got 24/7, 365 monitoring of the system, cloud-based, the reports are coming back to the people in the company only – and only to those people that need to know. Are these things that you guys are alerted to so that you call if something goes wrong, or is it basically just held in-house?
CN: It can be either. You have the option of adding our team into it and we can provide input. The one thing we have decided though is any time the system is deployed, we never want to see that system not functioning properly. We keep a close eye on it. The combustion measurements are only a small piece. There are also a lot of help measurements around the system itself, so we're able to keep an eye on the system. If something started to go wrong from a system standpoint, we haven't seen that yet, but if it ever does, we're able to send our technicians out to make sure that you don't get a break in that monitoring.
DG: Have you had any issues with companies being concerned about cybersecurity?
[blocktext align="right"]Get it right and keep it right and then get the most out of the gas that you purchase. Stop throwing away energy. [/blocktext]CN: Not yet. We deal with that in two ways. Number one is that the data we're taking is relatively agnostic. I'm going to see basically pressures and excess oxygen readings and it's not really associated with anything else. Typically, when we get an output through the customer's system, that is usually on the other side of their firewall so the system security is in place and we can have a clean channel out to our cloud. When customers are uncomfortable with that, we'll use cell technology to deliver that, so there is no interconnectivity to their system. We have thought that through. Some customers are more uncomfortable than others, but we've done it both ways, where we've connected through a portal in their system to get out to the internet and then we've also connected through cellular.
DG: Is it possible to have a completely contained system where there is no internet connectivity?
CN: No. Because a lot of the calculations and analysis is done in the cloud. It's not to say that we haven't been asked for that, and we are working on local displays for let's say a technician that just wants to walk up to the furnace and see how things are running; we do have provisions for that as well.
DG: “All fire is not created equal” we know that, so it sounds like PSEnergy has got some good options for people to help improve and maintain not only combustion efficiency but also furnace efficiency. The example you had in the article was for a commercial heat treater, but obviously this also applies to anybody who's doing any type of combustion heating, captive heat treaters, manufacturers or commercial.
What exactly would you emphasize to these manufacturers with their own in-house heat treating, or in the commercials, about the importance of combustion in the heat treating process?
CN: Combustion is really the core of their process. If I could leave you with a message that there are high value easily implemented solutions for achieving and maintaining that optimal combustion, then I think we've given the listeners and readers a little bit of value here. Get your combustion right and keep it right, and then look for that technology that is available out there that can help you get the most out of every BTU that you burn.
DG: Exactly. And the payback is almost a no-brainer in a lot of situations. Obviously, each situation is going to be unique, but the example you gave in the article, the payback was enormously good. It's certainly worth investigating.
CN: It is. It's always worth investigating when it's about achieving more output. When you can achieve more output and ring the cash register more and create more opportunities for selling additional product or new product capacity, those are easier ROIs. If we're just looking at wanting to save fuel, well sure, that pencils out in that case, it's just not the same sort of three-month turnaround or as quick.
In our case, we recommend three areas: Get combustion right and keep it right, with a tech-enabled service team and monitoring. I really wanted to point out, and we've heard this a hundred times– if it's not measured, it's not sustained. The core of heat treating is combustion, yet very few of us actually measure the performance of combustion. We might measure the output (temperature), but we don't measure excess oxygen, which is really the necessary metric to achieve the efficiency. The big steel example there kind of guides us. You should never wonder how well your combustion system is running. You should know with data. That's the core of your process.
So, get it right and keep it right and then get the most out of the gas that you purchase. Stop throwing away energy. Utilize these high value, easily implemented solutions and get the most out of it.
And the piece that we really didn't talk about was- train your team. There are combustion trainings out there. Ours is specifically geared towards combustion and really for heat treating operations, but train your team and talk about a common understanding and a common language around combustion. That dispels a lot of myths around combustion and exposes the team to the latest technologies and best practices.
Lastly, keep reading and listening to Heat TreatToday and Heat TreatRadio because that's the best way to stay informed on the latest technologies. You've got to keep up on it. All kidding aside, it is a really great way, the information that you guys provide is significant towards staying up on the technology.
DG: I appreciate that shameless promotion there. ~chuckles~
If someone wanted to get a little more information, what are you comfortable giving out as far as contact information for people to get a hold of you?
During the day-to-day operation of heat treat departments, many habits are formed and procedures followed that sometimes are done simply because that’s the way they’ve always been done. One of the great benefits of having a community of heat treaters is to challenge those habits and look at new ways of doing things. Heat TreatToday‘s 101 Heat TreatTips, tips and tricks that come from some of the industry’s foremost experts, were initially published in the FNA 2018 Special Print Edition, as a way to make the benefits of that community available to as many people as possible. This special edition is available in a digital format here.
Today, we offer one of the tips published under the Combustion category.
Combustion
Heat TreatTip 50
Effect of Exhaust Gas Temperature vs. O2 on Efficiency
Tuning a burner properly is important for safety. Tuning can also have a significant effect on efficiency in some but not all cases.
The efficiency of a conventional cold air burner varies significantly with the amount of excess air (related to % O2 in the exhaust products). Since a cold air burner does not use the exhaust gas to preheat the combustion temperature, the exhaust gas temperature is essentially equal to the furnace temperature. For a cold air burner operating at a 1,850°F, reducing excess air from 20% to 10% (reducing O2 from 4% to 2%) will increase efficiency by almost 5%.
Modern high-efficiency burners use the exhaust gas to preheat the combustion air as it enters the burner. Therefore, the temperature of the exhaust gas leaving the burner is significantly lower. The lower the exhaust gas temperature, the smaller the effect of a change in excess air on efficiency. For example, a self-regenerative burner operating at 1,850°F may have an exhaust gas temperature around 480°F. In this case, reducing excess air from 20% to 10% (reducing O2 from 4% to 2%) will only increase efficiency by about 1%.
As a general rule of thumb, reducing exhaust gas temperature by 180°F will increase efficiency by about 5%. So while proper tuning is important for many reasons, it does not have a significant effect on the efficiency of burners with advanced heat recovery systems.
Last month we began the discussion about the relationship between combustion safety and uptime, highlighting how combustion safety, reliability, emissions, and efficiency are inseparable. This month, we will explore the subject in greater detail and outline a path that can both reduce the risk of an incident and protect the bottom line.
