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

We are all increasingly conscious of our contribution towards greenhouse gas emissions. This awareness has led industrial operators around the globe to look at how they can operate in the most environmentally responsible way, particularly by reducing carbon emissions.

Our gas analyzers for clean air applications will optimize process control and safety and help you to meet environmental standards – keeping your plant and processes future-proofed.

Make the change to cleaner air – find out how we can help right now.

Building a cleaner world, together

As the global expert in gas analysis, Servomex plays a major role in helping a wide range of industries achieve their clean air goals. Our three-phase strategy focuses on the key process areas, working to reduce emissions and mitigate the damage caused by harmful pollutants.

Phase one:
Combustion efficiency

Controlling this important process reaction reduces emissions of key pollutants, including NOx, SOx, carbon monoxide (CO) and carbon dioxide (CO2), lowers fuel consumption, and improves safety. Relying on accurate measurements of oxygen (O2) and combustibles (COe) in the reaction mixture to achieve the optimum ratio between fuel and air.

Phase two:
Gas cleaning

This involves the safe removal of harmful substances from process gases that might otherwise be emitted by the plant. Typical applications within this phase include DeNOx treatments (i.e. ammonia slip processes) and flue gas desulfurization. A variety of gas measurements are required depending on the gas cleaning process being used.

Phase three:
Emissions monitoring

Measuring pollutants within the flue gas helps to determine process efficiency and protect the environment. Ensures/demonstrates that plant operators are compliant with the necessary regulations. Continuous monitoring is required to measure all the necessary components of the flue gas, including criterion pollutants and greenhouse gases.

The FluegasExact 2700 delivers effective combustion analysis

Designed to measure O2 and COe in flue gases for improved combustion efficiency and reduced emissions, the FluegasExact 2700 gas analyzer meets the most demanding needs of combustion efficiency applications in the power generation and process industries.

Armed with an integral sampling system custom-designed for operation in some of the hottest and most extreme industrial environments, it is the analyzer of choice for controlling a wide range of combustion processes.

Keith Warren
Product Manager – Process Oxygen, Zirconia & Oxygen Deficiency

The Laser 3 Plus Combustion is a compact, fast-response analyzer

Containing all the benefits of Servomex’s Tunable Diode Laser (TDL) technology in a light, compact unit, with unmatched installation flexibility plus cost and performance benefits, the Laser 3 Plus Combustion is ready for fast, accurate and responsive measurements in combustion and process control.

It provides the most stable, repeatable results with minimal installation and maintenance costs, offering a fast response measurement of O2, CO or a combination of CH4 and CO.

Rhys Jenkins
IP&E Spectroscopic Product Manager

Innovative sensor technologies

We provide an extensive range of sensing technologies to support every stage of your clean air strategy. Key technologies include:


Reliable and accurate oxygen measurements with Zirconia

Zirconia is a trusted oxygen sensing technology capable of providing measurements at parts-per-million (ppm) and percentage levels. Relied upon by industries around the world, it is an essential component of our SERVOTOUGH FluegasExact 2700 analyzer, which monitors O2 levels in in-situ combustion processes.

Learn more about Zirconia technology

Calorimetry provides sensitive measurements of combustibles

Calorimetry technology – also known as Thick Film Catalytic sensing – is used in our SERVOTOUGH FluegasExact 2700 combustion analyzer. It works alongside the FluegasExact 2700’s Zirconia sensor to deliver a measurement of both oxygen and combustibles from one analyzer.

Learn more about Calorimetry technology
Tunable Diode Laser

Obtain fast, in-situ cross-stack measurements with TDL sensing

Tunable Diode Laser (TDL) technology offers a fast-response, accurate measurement that is highly specific to the gas of interest. This non-contact, non-depleting sensing uses a single-line “monochromatic” spectroscopic technique that offers highly stable calibration, a continuous in-situ measurement, and the avoidance of optical cross-interference from other gases.

Learn more about TDL technology

Change is in the air with the Laser 3 Plus Environmental for NOx reduction processes

The Laser 3 Plus Environmental is a revolution in Tunable Diode Laser (TDL) Absorption Spectroscopy analysis: a highly compact gas monitor for in-situ cross-stack applications, which delivers exceptional performance benefits for clean air processes.

Installed directly into process ducts, it is ideal for monitoring ammonia slip during NOx reduction processes such as Selective Catalytic Reduction (SCR) or Selective Non-Catalytic Reduction (SNCR), controlling the level of ammonia slip to between 2-3 parts per million.

Rhys Jenkins
IP&E Spectroscopic Product Manager

Advanced digital CEMS analysis from the 4900 Multigas

Specifically designed for the Continuous Emissions Monitoring (CEMS) of flue gas, the high-performance 4900 Multigas can deliver up to four simultaneous gas stream measurements. It combines Servomex’s leading-edge sensing technologies with a modern digital platform, for next-generation performance at a low cost of ownership.

A compact, small-footprint analyzer, it integrates effortlessly into established systems and, when used with the correct sampling system, delivers high grade multi-gas monitoring of criterion pollutant and greenhouse gases.

Chris Davis
Product Manager

The rugged SpectraExact 2500 is ready for demanding processes

Servomex’s iconic industry-leading photometric analyzer delivers flexible single and multicomponent gas analysis capability for corrosive, toxic and flammable sample streams. The SpectraExact 2500’s reliable, accurate and stable real-time online process analysis makes it ideal for a range of process, combustion and emissions gas analysis applications.

Highly affordable, the SpectraExact 2500 uses an intelligent design and non-depleting sensing technologies to help to extend maintenance intervals and dramatically reduce ongoing costs.

Rhys Jenkins
IP&E Spectroscopic Product Manager

Innovative sensor technologies

We provide an extensive range of sensing technologies to support every stage of your clean air strategy. Key technologies include:

Tunable Diode Laser

Obtain fast, in-situ cross-stack measurements with TDL sensing

Tunable Diode Laser (TDL) technology offers a fast-response, accurate measurement that is highly specific to the gas of interest. This non-contact, non-depleting sensing uses a single-line “monochromatic” spectroscopic technique that offers highly stable calibration, a continuous in-situ measurement, and the avoidance of optical cross-interference from other gases.

Learn more about TDL technology

Paramagnetic is an innovative solution for percentage O2

Servomex pioneered the use of Paramagnetic sensing technology, and it remains a proven, trusted cornerstone of our oxygen (O2) analysis products. Used by many of our industrial, portable and multi-gas analyzers, it delivers fast and reliable measurements of percentage O2 concentrations.

Learn more about Paramagnetic technology

Infrared sensing provides real-time measurements of gases in a mixture

Infrared sensing is a flexible measurement technology based on the unique light-absorbing properties of some gases. It delivers a non-contact, real-time detection of the selected gas’s concentration in a mixture, and is widely used across the Servomex analyzer range, including our multi-gas analysis platforms, particularly for CO2 measurements.

Learn more about Infrared technology
Gas filter correlation

Gas Filter Correlation sensors deliver stable, ultra-accurate gas analysis

An advanced form of Infrared sensing, Gas Filter Correlation (Gfx) technology is ideal in applications with interferent background gases, delivering precise, sensitive measurements. It performs effectively where extremely accurate, low-level measurements are needed, or where background gases may interfere with the measurement, making it ideal for multi-gas CEMS applications.

Learn more about Gfx technology

Advanced digital CEMS analysis from the 4900 Multigas

Specifically designed for the Continuous Emissions Monitoring (CEMS) of flue gas, the high-performance 4900 Multigas can deliver up to four simultaneous gas stream measurements. It combines Servomex’s leading-edge sensing technologies with a modern digital platform, for next-generation performance at a low cost of ownership.

A compact, small-footprint analyzer, it integrates effortlessly into established systems and, when used with the correct sampling system, delivers high grade multi-gas monitoring of criterion pollutant and greenhouse gases.

Chris Davis
Product Manager

The MultiExact 4200 analyzes up to four gases simultaneously

The MultiExact 4200 provides high-specification multi-gas analysis of flammable gas samples and trace contaminants in a range of applications, using a mixture of Paramagnetic, Infrared, and Gas Filter Correlation technology.

Measuring up to four gas streams simultaneously, it is ideal for monitoring the common contaminants in hydrogen fuel production, analyzing percentage levels of O2, CO2, and CO. It can also measure percentage CO and CH4, and ppm-level CO, CO2, CH4 and N2O, for a variety of gas purity applications.

Rhys Jenkins
IP&E Spectroscopic Product Manager

The SERVOPRO NOx measures in key emissions applications

Utilizing Chemiluminescence detection technology to measure NO or NO/NO2/NOx concentrations in a single analyzer, the versatile SERVOPRO NOx can be calibrated for four measurement ranges starting from ultra-low to high ppm and is easy to install and operate.

The proven, light-based sensing technology makes the NOx perfect for continuous monitoring for industrial stationary sources emissions or ambient air, and fast enough for emissions testing in engines and vehicles.

Keith Warren
Product Manager – Process Oxygen, Zirconia & Oxygen Deficiency

Innovative sensor technologies

We provide an extensive range of sensing technologies to support every stage of your clean air strategy. Key technologies include:


Paramagnetic is an innovative solution for percentage O2

Servomex pioneered the use of Paramagnetic sensing technology, and it remains a proven, trusted cornerstone of our oxygen (O2) analysis products. Used by many of our industrial, portable and multi-gas analyzers, it delivers fast and reliable measurements of percentage O2 concentrations.

Learn more about Paramagnetic technology

Infrared sensing provides real-time measurements of gases in a mixture

Infrared sensing is a flexible measurement technology based on the unique light-absorbing properties of some gases. It delivers a non-contact, real-time detection of the selected gas’s concentration in a mixture, and is widely used across the Servomex analyzer range, including our multi-gas analysis platforms, particularly for CO2 measurements.

Learn more about Infrared technology
Gas filter correlation

Gas Filter Correlation sensors deliver stable, ultra-accurate gas analysis

An advanced form of Infrared sensing, Gas Filter Correlation (Gfx) technology is ideal in applications with interferent background gases, delivering precise, sensitive measurements. It performs effectively where extremely accurate, low-level measurements are needed, or where background gases may interfere with the measurement, making it ideal for multi-gas CEMS applications.

Learn more about Gfx technology

Chemiluminescence: non-depleting sensing for NOx measurements

Used in our SERVOPRO NOx gas analyzer, Chemiluminescence sensing is a light-based technology ideal for the measurement of nitric oxide (NO), nitrogen dioxide (NO2) and total oxides of nitrogen (NOx) in a wide range of combustion and emissions monitoring applications.

Learn more about Chemiluminescence technology

Our latest podcast examines how gas analysis can help industrial operators around the world to reduce their emissions of carbon and other pollutants

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

The second part of our clean air podcast, explores how industrial operators can reduce their emissions of carbon and other pollutants through better gas analysis.

MH: Welcome back to our clean air podcast. This is part two. I’m Matt Halsey, Application Development Manager at Servomex. And I’m joined by Barb Marshik, our Global Business Development Manager. Today, we’ll be continuing our chat about Servomex clean air solutions, we hope you enjoy.

Let’s talk about phase three of the clean air phases: this is our emissions monitoring phase. So, we’ve sorted out our combustion control, we’ve got our efficient combustion process, we’ve taken the gases we have produced, we’ve removed as many of them as possible. Now we have this tricky task of actually monitoring what’s coming out of our stack, and what we are emitting to the atmosphere, which, of course, is the part that that’s quite heavily regulated.

Barb mentioned a lot earlier about how this is done in the US, it’s done on a much a slightly different approach to how it’s done in Europe, using performance testing methodology. If you compare that to Europe, there’s a lot of regulations in place, you would have heard of MCERTS, you would have heard of QAL, which is used in Europe, and various famous test houses that most people have heard of like TUV, that take your equipment and issue certification. All these emissions are regulated, typically to fixed value, so maximum allowable emissions values for particular gases across different types of process.

Large processes will have very different numbers, very different limits, compared to small processes. And it’s normally done on things like the physical size, it could be megawatt output, if it’s an energy generator. So, Barb, could you tell us a little bit more about this performance testing method that’s used in the US?

BM: Right, and so I alluded to it before that there’s really two, two different types of processes that are used around the world. And so, like Matt talked about, the EU requires you to certify your whole system from the sample probe all the way to the analyzer and it includes the sample conditioning systems, and you have to use it and test it at a third-party testing site, and then they certify the system.

The US, on the other hand, you’ll hear people that ask about whether or not your system is certified by EPA – EPA doesn’t certify anything. EPA prescribes that a system will do this, and this is the performance that you must meet, in the field, on a stack, live. In most cases, they don’t prescribe what you have to use, but they do prescribe how it has to form. So what you’ll find is you’ll have a manufacturer or a company that will go out and put a system together, continuous emissions monitoring system on your stack, and then you’re required to have somebody come in and verify that it’s working.

So, prior to the end-user, the owner of the plant, being able to walk away from the system and let it run, they have to have what we call a stack tester come in and verify that the company that just installed your CEMS equipment installed it right, installed it at the right position. They do all sorts of tests on where it’s done, how you’re sampling it. And then they actually do side-by-side testing of your analyzer with their referenced method analyzer. And so that test is, the stack tester is considered to have the reference information, and so the CEM has to match it within a certain percentage. And that’s how the US has done all of its referencing and certification in the field.

Depending on what type of requirements, you might have to have a back tester drive in on, basically, a mobile lab up to your site, in general, once a year. Sometimes you might be able to, depending on the regulation, only have to test it once every three years. And again, depending on the regulation, you might have to have a stack tester come once a quarter. And so they perform the required testing on your site, and then if you pass, you’re good to go for the next set of days – it’s a quarter, it might be a half year, it might be a year, might be three years, you’re all set until the next time rolls around.

That’s what is being done in the US, and that’s the type of thing that China’s actually looking at, is how do they kind of implement these performance tests. They’re moving more towards a combination of the EU certified system, versus once it’s in the field, to actually have a Chinese EPA person go out and verify it, whereas the US doesn’t necessarily have EPA do the verification, they would be standing there or you know, watching all of this testing going on, but they’re not the ones actually doing the testing.

So it all depends on what country you’re at. Who does the testing in the US? It’s a third-party company and then EPA monitors it. In China right now it’s EPA that’s actually doing the testing. And so you’ll see a combination of all sorts of verification testing, because even though you certify the analyzer, it doesn’t necessarily mean that it will always work in the field. And so that’s where the US portion of it is to be triggered. And that’s where somebody comes in and modifies it. And so in those mobile labs, you’re going to have the same type of equipment that you have on a stack. And that’s where, again, our SERVOPRO 4900 Multigas comes into play.

That has a lot of different gases that is used in the field for verification testing. It’s also used in a continuous emissions monitoring system, it tends to use some of the big ones, again, that we’ve mentioned before is the NOx emissions. And oxygen is another one. Depending on what kind of gas you have, if you’re using natural gas as your fuel source, and you’re running a turbine, you might also be regulated and have to monitor CO. Not every source is regulated by CO, but it’s all regulation-dependent on what gases you’re going to monitor. But the 4900 has been used in both mobile labs, as well as a stationary source in a continuous emissions monitoring system.

The change that you’re seeing, however, is the NOx levels are starting to be dropped. And so because it is quite hazardous to the ozone layer, countries are starting to require tighter and tighter controls on the NOx emissions. And once you start getting into less than 10 ppm, your typical non-dispersive infrared analyzer is just not going to cut it. So what you’ll see is a lot more users turning to chemiluminescence detectors. That’s where our SERVOPRO NOx system comes into play. It is a chemiluminescence detector, it goes to very low levels, and also very high levels, all with the same analyzer. It is a little bit more, I shouldn’t say challenging, but it has a lot more, the parts are different, they do need a little bit more maintenance than an NDIR does. But it also allows you to go to really low levels of detection, which is why it is starting to become the analyzer of choice at low-level NOx emissions and in a continuous emissions monitoring system.

Or, as we talked about before, in this gas cleaning process, you can also use chemiluminescence to look at, not only are we looking at the ammonia coming off the process of an SCR/SNCR, but you could also look at “did I actually clean up the NOx?”. So you can directly look at it right at the source. And chemiluminescence again, when you’re looking at the source and looking at it as a process control, you need to have the analyzer to be very fast. And both the 4900 Multigas, as well as the SERVOPRO NOx are fast analyzers. When you’re looking at it as a stack, now you can slow it down, and so you can actually look at the gas a lot longer, you get better signal to noise, so both of those analyzers also work well at the stack. The big plus is, can it work faster? And so yes, both of those can work faster, allowing you to use it in the gas clean-up stage, as well as also use it in the gas emission stage.

MH: Yes, of course, on the stack, you move a bit more towards averaging measurements and things like that, that you’re reporting as well. So that, as you said, you’re allowed to do a slower measurement. It’s interesting, you talk about the technologies as well, you mentioned some of the differences between your more traditional NDIR, and then there’s chemiluminescence, that’s something else that the some of the European, or the more European- type emission standards regulate, is not just the emissions limits, but also the technologies used to monitor those emissions. They’re actually specified in a lot of the standards.

So, for example, the reference technology, I believe for NOx is chemiluminescence, but you are allowed to use alternative technologies and one of which is NDIR, or in our case gas filter correlation specifically, which is just a type of infrared. Oxygen, of course Paramagnetic which is something that Servomex is really renowned for, that’s very much our core technology and how we started, so oxygen for the oxygen reference measurement, you have to have for emissions, and various other types of technology.

I don’t know Barb, if you can speak for the American regulations, whether they are doing the same thing. Are they specifying technologies for different gases?

BM: In some cases, they do, depending on how tight the regulation is. You are bound to very certain analyzers. You can ask for an alternative and sometimes you will see them, so they do it as a case-by-case basis. But there are places, especially in the power generation facilities, where you’re required to use very specific analyzers. And if your analyzer can’t make that performance it is not allowed. So you’ll see in there that, yes, these are the types of analyzers that you can use. And there is a recommended process and recommended analyzer that they used before. They validated it, and they recommend that you use this. But if you want to use something else, you just have to prove that is equivalent to any of these others.

MH: And of course, this makes it very challenging for an equipment manufacturer, because when you’ve got a product that is being distributed globally, it’s important to make sure that you’ve got the right technologies, you’ve got the right certifications for all the different countries. A really good example of that would be the Asia-Pacific area where all of the different Asian countries have different rules, different regulations, they require their own specific types of certificates, which are all based, fundamentally, on MCERTS, which is a UK thing. But it makes it very challenging to keep up with what the world’s doing.

And of course, this is a very dynamic market at the moment, you know, these emissions regulations are changing every year. I think some of them have almost, these maximum limits, almost halved in the last couple of years. It’s becoming such a hot topic.

Let’s talk about the PS18 specification of the EPA regulations in America, could you just give us the highlights of that?

BM: It’s almost very controversial in the United States. I had mentioned earlier that some of the states are starting to monitor ammonia. Well, the problem is that the US EPA does not regulate ammonia. And so where the challenges is, is that because the US EPA doesn’t regulate it, they don’t have a standard by which there’s a performance standard that each state would have to follow. What EPA asks the states to do is, they could call up EPA and say, “well, what would you recommend?”, and so what EPA has recommended is that they follow the Performance Specification 18.

Performance Specification 18 is for hydrogen chloride or HCl. But the reason why they recommend this one is that it HCl was the first performance specification that allowed tunable diode lasers to be used. Prior to that, everything was a probe – you grab the sample, you bring it to your analyzer, it’s either done hot-wet, or you drop the water out, you do it cold. So the problem you have with things like HCl, and ammonia is, again, they’re wet,

or they’re polar, and they absorb into the water, so that when you drop the water out, guess what? You also dropped your HCl and your ammonia out.

When you do those types of gases, you are not allowed to use a typical NDIR, which requires you to remove the water, you have to do it hot and wet. Not to say that an infrared analyzer can’t be run hot-wet, but what EPA has started to allow is for you to do it right across the stack. And so the best technology for stack monitoring is the laser – it looks across the stack, it averages the gases across the stack. That brings up another issue, because before you could clean out your sample tubes by putting a nitrogen gas in there, because you have to zero your analyzer out. With an extractive-type system, you basically run nitrogen down your probe, it shows up as nothing in your analyzer, you zero it out, you prove that you’re seeing a zero, you can put a calibrated gas through that probe, prove that you’re reading the right numbers.

But how do you do that when you’re always seeing the stack gas? So that was the reason for EPA developing PS18, to take on that challenge and say: this is how you would do it. Because you’re always going to have that stack gas. And so you’re going to be able to do a bump gas, meaning I’m going to put a contribution of ammonia that I know, run it up to the gas to the actual laser that you’re running, I’m going to be able to see it and the stack gas at the same time. And then they tell you a number of different ways of how you treat that stack gas in order to get back the correct numbers that you need.

But the problem with PS18, unfortunately, is that it’s pretty difficult to read, and so EPA is willing to change the methodology for the performance testing for ammonia to make it less onerous than it is currently for HCl. And there’s a reason for HCl being difficult, because you’re not only looking at low levels, but you also have to look at really high levels of HCl, when you’re looking at a cement plant, because you’re going to have high levels of HCl that you have to see at the same time.

That’s not the same case in ammonia – you’re always going to be at that low level, because you’re required to. Eventually, if the US EPA does come up with a stance and they’re going to start regulating, they will follow the performance specs 18, or what we call PS18. So, in general, what companies are trying to do, if they’re being tasked to actually follow this or at least start monitoring it, they’re trying to make sure that the analyzers are following PS18. That’s what instrument manufacturers are doing, is that you take your analyzer and then you test it based upon what PS18 says for HCl, but you just take HCl out of the equation and put ammonia in there. And you verify it according to that.

That’s actually an ongoing process, as we speak, right here in the United States, where they are looking at an ammonia laser on a stack to be used for continuous emissions monitoring. And most places are looking at it following PS18. So that’s what you’ll hear a lot, “does your analyzer follow PS18?” and that’s what we have, is a Laser 3 Plus being tested for PS18 and again, the

US doesn’t certify, but it requires you to say: “I did test it and yes, it does follow PS18”.

MH: And I fully suspect the rest of the world will follow suit at some point. I can see ammonia becoming in a few years a probably quite heavily regulated emission from especially from you know, from my perspective from the UK and Europe as well.

BM: The 4900 is actually a unique analyzer for this market in particular. If you do remember, if you come back to those again, it’s the only one on the market that has a dual inlet and outlet. And so NOx emissions, or NOx monitoring, you need it really fast and you want to have NO and NOx at the same time, it’s the perfect analyzer for it. Other than the fact that it’s still not low enough, it’s perfect!

MH: Okay, Barb, just to think about closing this out, I want to talk about one more subject, which is some of the other things that customers are now starting to do to reduce their CO2 output, specifically, as opposed to the other types of emissions that we see. You mentioned earlier about hydrogen, and hydrogen as a fuel. So, can you go into a little bit more detail on that subject?

BM: Yeah. Because corporations and countries, especially the EU, are really trying to make some drastic changes in their carbon footprint, they’ve looked around and there’s all sorts of different ways that you can lower your carbon footprint, and in particular, CO2, which is why people call it a greenhouse gas. One way of doing that is looking at alternative fuels, alternative ways of doing things that you used to do. And so there’s a huge push to start using hydrogen as a fuel source, rather than natural gas or even feed streams from a refinery. If you take those types of gases and switch them out with hydrogen, there are some major equipment changes that you have to do because it burns differently, it reacts differently with metals. But there’s lots of research going on with that.

But how do you get hydrogen? Well, it turns out that 90 to 95% of the world’s hydrogen is created from steam methane reforming. So it actually does come from natural gas. And so when you use steam methane reforming, you create a large amount of CO2, we also have hydrogen. Now we’ve got our product that we’re looking for, but what are we going to do about that CO2? So that’s where you’ll hear people start talking about carbon capture and sequestration or utilization.

In order to allow the methane reforming being part of this new hydrogen economy with a low carbon footprint, you have to get rid of the CO2 that’s liberated during the process. And if you can do that, then you create what people call blue hydrogen. Blue hydrogen is where I’ve created hydrogen, I know it has a lot of CO2, but I’ve done something with the CO2. And sequestration means grabbed it, shoved it under the ground in a storage facility or a cave or some kind of big hole or use it to actually get more oil

and gas out of the ground, like buried under the ocean. So you’re holding it there.

A better process, that I’m personally fond of, is utilizing it as some other type of solid or liquid. And some of those processes you’ll see is methanol. You can create methanol from CO2, you can create carbon black from CO2. So those are some of the products that people are looking at. They’re also looking at using CO2 in the direct production of cement. So you’ll start seeing a lot of research being done on “what am I going to do with the CO2? Here’s a solid or liquid phase that I can actually transform it into”. And that’s the utilization part of carbon capture. But that’s what you’re studying to see. And, you know, the great thing is, we actually have a lot of analyzers that do play into this market.

So this market is slightly different, because now I’ve got a product called hydrogen. Well, hydrogen is actually a hazardous gas, and it’s flammable. So you have to have analyzers that are going to be able to be part of the process that monitors the amount of oxygen, monitors the impurities, that are in the hydrogen stream. And that’s where our 2500s come into play. When you’re creating CO2, when you’re creating CO, they are certified for Class one Div one in some cases, can be placed right on the process and be part of your solution to making sure you’ve got safe and proper impurity levels of hydrogen at all portions down the stream.

MH: So thank you, everybody, for listening in on another Servomex podcast. And hopefully, we will be bringing many more to you in the future on a variety of topics. Thank you so much for calling in and helping out with this podcast today. I really appreciate your time.

BM: Thank you, Matt. I appreciate it, and I hope everybody enjoyed the podcast. You can always contact Servomex for more information on analyzers, just to chat about you know how we’re positioning ourselves for this new clean energy market.

MH: Yeah, absolutely. Please do visit our website You can find out more there about our clean air solutions. We’ve also released, very recently, a magazine, one of our regular ES magazines dedicated to this topic of clean air, so please do grab a copy of that from the website and have a read. Don’t forget to listen to our other podcasts – they’re also available on the Servomex website. I think this is number three in the catalog so far, so we’re pumping them out at the moment – look out for more in the near future! But thank you once again for listening, and we’ll catch you next time.

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