Change is in the air – make Servomex your partner for a cleaner future

MH: Welcome, everyone, to another Servomex podcast. It’s me again, Matt Halsey, Application Development Manager, here at Servomex based in the UK. And I’m joined today by Barbara Marshik, our Business Development Manager for the Americas, who is currently five and a half thousand miles away from me. Due to the wonders of technology, we’re able to talk today, so welcome, Barb.

BM: All right. Thank you, Matt. Appreciate it.

MH: So today, we’re going to be talking about the topic of clean air. Those of you that have listened to our previous podcasts, you’ve already heard this mentioned, you know we’ve been talking about combustion control quite a lot, process heaters, and thermal power stations. This is a much bigger topic. And we figured we want to go into it in more detail today.

So, this topic of clean air, what do we mean by clean air? Well, I’ve mentioned this in the past, our customers are becoming increasingly sensitized to what their processes are emitting. And all over the world, countries’ emissions regulations are becoming tighter and tighter. It’s becoming increasingly important to both eliminate the emissions that you’re producing, and of course, for those that you are producing, it’s important to then monitor them, measure them, and ultimately report them to your local Environment Agency.

So here at Servomex, we break the clean air theme into a process with three core areas. We talk about phases of combustion control, gas clean-up, and then emissions monitoring. So, Barbara, could you give us a little overview on what we mean by combustion control to start with?

BM: Yeah, so with combustion control, you’re actually looking at the process itself. And generally, what people will look at is whether or not the gas or the fuel that you’re using is burning efficiently. So you tend to monitor the gases. And so we’re looking at the gases of combustion itself – we tend to look at oxygen, and carbon monoxide. And that’s telling you whether or not you need to add more fuel, or if you have to add more oxygen in order to make your process run efficiently.

However, in the last few years, what’s become even more important, rather than the money you save on the amount of fuel that you use, is whether or not you’re we’re emitting. Because the regulations are starting to become much tighter on emissions control, just doing combustion control and looking at your fuel and oxygen usage isn’t going to help you in the end, if you’re emitting too much nitrogen oxides, or carbon monoxide. Those are the two gases that combustion analyzers will be required to monitor and lower.

Along with the Paris Accord, however, there are a lot more countries that are signing on to reduce carbon dioxide. So it’s greenhouse gases, in effect. And

combustion is one of those processes that emits quite a bit of CO2. That’s part of what we’re going to be talking about in the other two phases as well: what are you going to do with that CO2? And how do you lower it? Most countries across the world are looking at trying to provide a low-carbon process; the companies themselves are looking at lowering their carbon content. And that’s where you’ll see a lot more emphasis on ‘how do we get rid of the CO2?’ or ‘how do we minimize it?’. And that’s where again, later on, we’ll talk a little bit about what is starting to become the new buzzword called the hydrogen economy.

MH: Absolutely, Barb. Yeah, I totally agree. And it’s, it’s an interesting subject you mentioned, CO2, of course, being the most famous and the biggest of the greenhouse gases that everyone’s heard of. And you know, the irony really is that with an efficient combustion process, your ideal gas to produce, of course, is CO2, because it’s a sign of complete combustion. It makes it a difficult gas to then actually reduce because in effect you are trying to produce CO2 from burning your fuel, whilst trying to minimize the emission of other gases, other pollutants or other toxic gases, like sulfur dioxide, for example, from things like coal and oil, and CO, carbon monoxide. which of course is a sign of incomplete combustion.

So, I want to take this opportunity, as well, just to mention a process that we’re noticing is making a bit of a resurgence, which is something known as oxy fuel combustion. It was actually utilized a number of years ago now, but has always been considered to be a little bit unsafe at times. And really what you’re doing here is instead of performing combustion in the more traditional sense of using air to source your oxygen that you need to support combustion – so normally just taking in the air that surrounds us and helping that to feed the combustion process – you actually use pure oxygen.

And the theory here says that most of the NOx in a process comes from the nitrogen that’s in the air that you’re using to support combustion. So there’s just under 80% nitrogen. If you use pure oxygen, you remove the nitrogen, so you’re not going to produce nearly as much NOx in your process. But of course, using 100%, oxygen has some negatives, unfortunately. Number one, it’s actually quite expensive to fuel your process with pure oxygen. But the predominant con, I would say is the fact that it can be relatively unsafe. You have to quite closely monitor combustion, if you’re using pure oxygen, because it’s such a lively gas and obviously an oxidizer.

So, combustion control becomes very, very important; you want to make sure that you’re moving neither towards a fuel-rich condition, which can be dangerous anyway, but you don’t really want to be moving too much of an oxygen-rich condition, either, because that, in this case, could be equally as dangerous. But we are certainly seeing a resurgence of this, we’re starting to have potential customers come to us asking these questions about this process. They’re obviously trying it again, really, with the same combustion technologies that we’ve spoken about in this podcast already; your more

traditional Zirconia, or the sort of newer TDL-type technologies, are the perfect analyzers for this application.

And really, what we’re reinforcing is the fact that in these types of oxy fuel processes, that combustion control is absolutely critical. It’s not the kind of process that you would want to run, theoretically, which is, which is done sometimes. Sometimes the stoichiometric control point or the, the peak efficiency point is, is worked out mathematically and is controlled that way. Other times, on smaller processes, you can be in a situation where you actually use the emissions measurements of oxygen to help control combustion, which, when you’re talking about oxy fuel is not so much a good idea. And you definitely want combustion control analyzers at the point of combustion.

Okay, so I just wanted to slip that process in there, because it’s an interesting one that, as I said, is making a bit of a resurgence, I think, as people are coming more sensitized to emissions in general, in this case, NOx.

So, some more on CO2 emissions, because it is such a high-profile topic right now in the world. If you look at some of the numbers, since the 1970s, when all this data was started to be recorded in anger, the CO2 emissions have increased by around 90%, a massive, massive increase. And this has really been driven by the ever-growing population of the planet, the demand for more energy, the demand for more product, more chemical manufacture, which of course, contributes more and more CO2 to the atmosphere.

By far the biggest contributors to that increase is fossil fuel combustion and industry, heavy industry. Around 80% of total CO2 is produced by heavy industry and general fossil fuel production, so it’s a really, really big number. And if you look at it on a country-by-country basis, your three biggest polluters, the three biggest CO2 emitters, are China, who have a really big chunk, about 30%, the US who sit at about 15% – so over where you are, of course, Barb – and then the EU countries, including the UK, about 10%. And the rest is made up of other growing countries, especially countries like India, and other countries in Southeast Asia.

All these countries are now desperately trying to scramble to reduce their CO2 emissions. There are various agreements and accords in place – you mentioned the Paris Agreement, Barbara, earlier which, of course from a US perspective has been in itself quite a big topic recently, with the initial withdrawal from it under the last presidency and now rejoining it under the current presidency. And countries like China, you know, who are the biggest polluter of all the countries, are starting to now match their emissions targets and their emissions regulations. They’re following suit of the European regulations and the American regulations, who obviously have very stable and comprehensive emissions regulations in place nowadays.

BM: And it turns out that, you know, emissions regulations is actually a pretty big, broad subject. And what you see happening is that most countries

outside of the United States tend to follow the EU regulations. However, what you saw, probably in the last five years, maybe, is that there’s a shift in Asia. It used to be they followed all of the EU regulations, but then they’ve been shifting, especially China, more towards a performance-based emissions regulation, which is what the US provides. So it’s less prescriptive, yet you still have to follow quite tight regulations. And it’s a matter of, you know, having somebody witness when you’re verifying that a smokestack actually has the emissions or is regulating the emissions like they’re supposed to.

And that’s always been the issue – does the country itself have technical people that can actually go out and verify that these smokestacks are emitting as low a level of emissions as possible? The other issue that you have with looking at emissions regulations and energy sources and things like that, is there are so many countries out there where their cheapest fuel source is coal. And because of that, most countries are still very reluctant to get rid of coal as a primary source of fuel.

However, there are a lot of new technologies that are out there that are converting coal to like a syngas, so it’s hydrogen and CO. And so you’re lowering your CO2 emissions, while still using this very cheap source of fuel.

So those are some of the types of activities that are going on: how do you take the cheap fuel source and make it into a more a cheap, and let’s say dirty, fuel source, and make it into something that’s a lot more carbon- neutral, or carbon-clean, low carbon types of fuel, and still provide your own region with its own fuel sources?

And so that’s one of the things that’s changing. Not only are the limits of emissions going down, but you’re also seeing a lot more activity in lowering your greenhouse gases. And like you mentioned, the US took a pause on greenhouse gases. But with the change in administration, they have been moving along with greenhouse gas emissions, trying to lower your CO2 emissions. While it’s regulated by regions, it turns out that we are living in a global economy, and corporations have taken it upon themselves to look at their global carbon footprint. And because of that, you’ll see that, even though a country might not be regulating their emissions, large corporations are. So while it might not be regulated by each region, you’ll see this happening anyway.

So, regardless of whether or not the region wants to be in the greenhouse gas emissions and lowering your emissions, if you’ve got a large corporation that is part your economy, you’ll see that they are lowering it across the board, countries where there’s less regulations, these companies are starting to take a real hard look at how they are doing everywhere, not just in the areas like regions of the EU, regions of China, or in the US and lowering emissions, they’re actually doing it wherever they have plants.

MH: So, continuing our discussion around combustion control, I mentioned that we’ve spoken about this in a bit more detail in previous podcasts, so we

won’t labor the point. But, it’s worth touching on the basics again. The idea here is, of course, maximizing efficiency, minimizing fuel use, and then ultimately minimizing emissions.

At Servomex, we have two core products, two core technologies, really, that can achieve this continuous hunt for the maximum combustion efficiency. We have our Zirconia and Thick Film Calorimetry-based extractive FluegasExact 2700 analyzer. This is your more traditional technology. Zirconia technology has been around for years and years, and was started to be used in the 1950s and 60s in the automotive industry, and has developed into a very competent combustion control technology. And then on the other hand, we have the much more modern Tunable Diode Laser product, the Laser 3 Plus, which is available in a number of flavors for combustion control, primarily the oxygen, and then the carbon monoxide version, which can be coupled with a methane measurement as well, which is that all-important safety measurement.

This, of course, is something we haven’t mentioned in this podcast up to now, but one of the other real big drivers behind combustion control, paired with, of course, emissions reduction, which is the topic today, but also the minimizing fuel use, and therefore fuel costs, is of course, safety of the plant and safety of the people, which is always worth mentioning. And on a lot of these big industrial plants, refineries and chemical plants and things like that, the process heaters are typically one of the largest contributors to these greenhouse gases and emissions on the plant. They’re running all the time producing heat, which is taken off for elsewhere in the plant. And actually, our second podcast that we produced in our recent series was all focused on process eaters. So that’s well worth a listen, if that’s a topic of interest to you.

When we move on to the second phase of these three phases that we mentioned at the beginning, we start to look at gas clean-up. So again, Barb, could you give us a little bit of background around what we mean by gas clean-up?

BM: Yeah, so because you’re regulated for emissions, now that you’ve got your process heater, and you’re giving off CO2, you’re also giving off other types of criteria pollutants, as they call it. And one of the biggest ones is nitrogen oxide, so it’s NO, NO2, and sometimes N2O can be regulated, but the big two, or really NO, and NO2. And so what plant can do, the most efficient way of removing these nitrogen oxides – which are created, by the way because of the high temperatures that you’re using in order to combust your fuel – there’s air in there. And because there’s air in there, that means there’s a lot of nitrogen. And so now you’ve got oxygen and nitrogen reacting to create, NO, which is an acidic gas, which is one of the reasons why they regulate this so much, because it causes acid rain. And again, it’s a criterion pollutant, and you’ll see that every single country that’s looking into emissions monitoring is going to have some sort of regulations built around

NO and NO2. Generally, what you hear people talk about is NOx, it combines the two of them together.

There’s ways of reducing your NOx emissions by having a more efficient burner, so it doesn’t run as hot, you can lower the NOx emissions. There’s a lot of changes that are going into your process heaters, there’s also changes going into if you’re doing power generation, how you do that lowering the temperatures. Low NOx burners is one way of doing it. However, it’s not enough; if you have to reach some really low levels of NOx emissions, you’re going to have to do a little bit more work than just retooling your burners. And one of the things that one of the biggest ways of doing that is to reduce the NOx in a process.

It can be referred to as a DeNOx process, but in general, there are two types that people will use: an SCR, so you’re going to have some kind of catalyst that will reduce the NOx, or SNCR, which is not using a catalyst, but it’s doing the same sort of thing – I’m going to reduce the NOx by letting my reactants take a lot longer to react. So I’ve got a path travel that’s much longer, but you also have to have a lot higher temperature in order for this to do it.

The most efficient way of doing this is adding ammonia. If you add ammonia to your emissions, or your combustion gas stream, after all the fuel is done, you can use that to actually scrub out and react with the NOx to basically give you oxygen and nitrogen as your by-product. That’s the goal. What people try to do is, you want to reduce all of your NOx to zero, so you tend to run your process at an excess of ammonia. If you have too much ammonia, it’s going to cost you money, because it is a feedstock that actually is quite expensive.

The other part though is you’ve got to worry a little bit if you’ve got too much ammonia in there because it reacts with SO2 that you might have in there, and it can react with a whole bunch of other things like carbon dioxide to create particulates. It’s an acidic particulate. Further downstream, you have an acidic process that can actually eat through your metal, any kind of metal components that you have downstream. So, it is actually an issue that you have to monitor.

One of the things that we do, is that we place one of our Laser 3 Pluses on the outlet of an SCR or SNCR, and we monitor directly the amount of ammonia that’s coming through the slipstream. And because you can actually see the ammonia directly, you’re not converting it from something one to another: you know exactly how much is in there. That signal is then fed back to a data control system, and then you can adjust the amount of ammonia. If you’ve got too little coming through, or too much coming through, you have a feedback loop that can then again save you money and actually save you trouble downstream from basically not having particulates forming.

And it turns out that, while this is gas cleaning process, it also is going to end up being in some places, emissions monitoring processes as well. Countries are starting to regulate ammonia because of this process. Ammonia itself isn’t necessarily a greenhouse gas, or it’s not a criterion pollutant. But what it is, is that it has a very distinctive smell and too much of that in your in that regional area where somebody has an SCR or SNCR in their clean-up process, it becomes a nuisance, a regional nuisance. In the United States, the US doesn’t regulate it, but there’s several states that are starting to regulate the amount of ammonia that can be let off in a regional area. And so some of the states – there’s Texas, California, New Jersey, Pennsylvania – are looking at this. Generally what happens in the United States, California takes the forefront and is trying to set the emissions limit of ammonia.

So that’s one of the things that you’ll start seeing the laser being used for, because, again, now that I’ve already got a continuous emissions monitoring system on there, you don’t necessarily want to add another huge analyzer that has a whole bunch of multi gases looking in the gas stream, you just want to look at that. Because now I’m regulated with that one gas, I just want to add one more analyzer, and that’s where that Laser 3 Plus is the perfect analyzer to be implemented on a stack. Again, it’s looking at one gas, it can be easily installed, and it’s very reproducible at this point.

And so that’s what people are looking for: easy to install, you don’t lose your gas, it directly measures the ammonia, ammonia is a tough cookie to crack, because it’s so sticky. And so if you’re going to extract it, and then look at it elsewhere, you know, in your CEMS shelter, you have to worry about loss of ammonia – by the time it gets to your analyzer, do you even know what you had in there?

That’s one of the really big pluses for putting a laser right on the stack, because you’re not actually extracting the sample, you’re looking at it directly in place, you don’t have to have any sample conditioning at that point. So that’s why people are starting to really look hard at lasers, not only for your gas cleaning process, but also now putting them at the stack and looking at the stack and saying, yep, this is it, you’re good to go. You don’t have that smell coming out and irritating people in the nearby regions.

MH: And you get the other benefits, of course of the laser that we’ve discussed in the past. But non-contact is the real biggie that you’ve mentioned, especially with ammonia, because it is so sticky. But also the fact it’s just so fast to respond, which of course is very, very important for process control applications where you’ve got this direct feedback to the ammonia injection point, you need a very fast speed of response. And also, of course, the sensitivity of the measurement.

The levels of ammonia we’re talking about here, in that process you just explained, are tiny – three, four ppm that you’re trying to let no more than that slip through this process, because any more than literally a couple of ppm could cause this this downstream damage that you mentioned, this

formation of the infamous ABS and some other things that corrode the pipe work.

The other thing this measurement is used for, that I’ve certainly seen, is for monitoring the health of the of the catalyst in an SCR reaction. Over time that catalyst will degrade, it just does. It shouldn’t, but it does in a lot of applications. It’s being sometimes been exposed to lots of dusts as well and abrasion, you know, abrasive dust or wearing it down. And of course, as the catalyst degrades the ammonia reaction with NOx will degrade, which means you’ll need more ammonia to react with the NOx. And so it’s also a good way of monitoring that catalyst health, because those catalysts, when they need replacing are not cheap to replace, you know, and it’s a really big project to get them out and get the new ones in and quite often involves plant shutdowns, which in itself is a very, very costly exercise.

One of the other really key gas clean-up applications that we see is called FGD, flue gas desulfurization. This is to remove the other quite heavily regulated component in flue gas, which is the SO2, which is formed only with particular fuels, things like coal, oils, waste gas streams that are burned as a fuel, they can all contain sulfur compounds which go on to reduce SO2 and SO3. In this FGD process, what they do is they spray a wet slurry of, typically, something like limestone, through the flue gas, and that will react with the SO2.

So what it produces is, you get calcium sulfite, you get CO2 and you get some water left over. With a little bit more O2 added to that you can form calcium sulfate, which is actually then a useful by-product because that goes into all kinds of things. That’s collected by these guys that are running the process, it’s sold, it goes off to make things like cement, it’s used in the agriculture industry, it’s used in the construction industry for other things. So that gives the user a tangible and useful by-product they can sell on and even make some more money out of.

Again, it’s important to monitor the efficiency of this flue gas desulfurization process, so what you can do is you can put an analyzer either post-FGD, to monitor the SO2 that’s still making its way through. And of course, if SO2 is making its way through, then you can tweak your water wash and scrubbing system. But you can also have an analyzer before and after, which is a way of monitoring truly the efficiency of one versus the other.

Now, of course, the concentrations of SO2 that we’re talking about here are quite different on the inlet and the outlet because you’re hoping on the outlet, you’ve got far, far less than you had on the inlet (or the process isn’t working very well). One of the bits of equipment that we can apply to the inlet especially is our 4900 Multigas which can have an SO2 Gas Filter Correlation-type Infrared technology fitted, which can monitor lower range up to a much higher range in the hundreds to thousands of ppm SO2.

Relatively simple technology, infrared at heart uses gas filters to make the measurement much more accurate. These types of analyzers, because they’re extractive and they are contact measurements, they involve removing a sample of gas from the process, analyzing it, obviously putting it back in, typically. They rely on very much a dry-based analysis, so we do need to consider sample systems in such installations.

And again, I’m going to point you back at a previous podcast, I’m going to get the numbers up on the previous podcast, but our European Business Development Manager, Steven, spoke a lot about the types of system that are needed for these types of products. So fundamentally a way of removing the water, conditioning the sample, regulating the pressure and flow into the analyzer, of course in very simplistic terms.

Thanks for listening to part one of our clean air podcast. Barb and I will be back soon to continue our discussions. If you want to learn more about Servomex clean air solutions, please visit the Servomex website at servomex.com.