If you’ve ever stood near a large power plant and caught whiffs of faint, unusual gases drifting from its perimeter, you might’ve wondered: where does all that industrial by-product gas go? For decades, many of these gases—leftover from fuel processing, steel manufacturing, or even the breakdown of waste in adjacent facilities—were either flared off, released into the atmosphere, or wasted entirely as unused energy. Today, however, Industrial By-product Gas Recovery Units (IBGRUs) are changing that. As a supplier of these units, I’ve spent the last 12 years working side-by-side with power plant operators, troubleshooting kinks in systems, and watching as what was once a nuisance becomes a valuable, low-carbon power source. Let’s pull back the curtain on how these units work, and why they’re not just a piece of equipment—they’re a game-changer for the energy industry. Industrial By-product Gas Recovery Unit
First, let’s get clear on what industrial by-product gas (IBG) actually is, because that’s the starting point for every IBGRU. When power plants or neighboring industrial facilities make fuel or process materials, they produce gases that aren’t part of their core product. For example, steel mills generate blast furnace gas (BFG) and coke oven gas (COG) as by-products during iron smelting and coke production, respectively. Coal-fired power plants produce syngas when they burn coal in oxygen-limited furnaces, a mix of carbon monoxide, hydrogen, and small amounts of methane. Even waste-to-energy plants pull out methane from decomposing municipal solid waste, a gas that would otherwise leak into the air and trap 28 times more heat than carbon dioxide over 100 years, per IPCC data. For years, these gases were seen as useless, or even dangerous—so plants flared them, which is essentially burning them off in a controlled but wasteful way that releases CO2 without capturing any energy. Flaring also wastes a resource: the energy in one cubic meter of BFG, for example, is roughly equivalent to 0.1 liters of diesel fuel. Multiply that by the millions of cubic meters a single steel mill produces daily, and you’re looking at millions of dollars in lost energy every year.
An IBGRU exists to capture that gas, clean it up, and feed it into a power plant’s existing turbines or boilers to generate electricity—all while cutting emissions and saving operators money. Let’s walk through the process step by step, as I’d explain it to a plant manager who’s never worked with one before.
The first stage is capture and collection, and it’s all about plumbing. Before any treatment can happen, the IBG has to be pulled from wherever it’s generated: steel mill blast furnaces, coke ovens, or waste processing lines. This is where our units integrate with a plant’s existing piping network, usually with suction pumps that create a slight negative pressure in the lines. Why negative pressure? Because it prevents unburned gas from leaking out into the plant’s workspace, which is a huge safety win. I’ve seen too many operators try to skip this step, using positive pressure instead, and end up with gas seeping into maintenance areas—avoidable with a well-designed suction system.
But raw IBG is messy, and if you tried to burn it directly in a turbine, you’d break the equipment fast. Take blast furnace gas, for example: it has a high nitrogen content (around 60%) and lots of fine particulate matter (dust from the furnace, tiny metal particles), plus small amounts of sulfur and moisture. If that dust gets into a turbine blade, it acts like sandpaper, wearing down the blade in months instead of years. Sulfur, meanwhile, would damage the turbine’s corrosion-resistant coatings and cause toxic emissions, like sulfur dioxide. That’s why the next stage is treatment, and it’s where most of the IBGRU’s engineering happens.
Treatment is split into two main parts: primary cleaning and fine cleaning. Primary cleaning is the first stop for raw IBG, and it’s all about removing the big stuff: dust and heavy liquids. Most IBGRUs use a set of cyclone separators here. Cyclones work on centrifugal force: as the gas spins around the inside of a cone-shaped chamber, the heavier dust particles get flung to the walls and fall to the bottom, where they’re removed via a drain. For really heavy particulates, we sometimes add a water spray in the cyclone—this is called a wet cyclone, and it captures even more dust while also cooling the gas, which is important because raw IBG can be hot enough to warp pipes. After the cyclone stage, the gas still has some smaller dust particles, plus sulfur compounds and moisture, so it moves on to fine cleaning.
Fine cleaning is where the unit really shines. For most of the IBGRUs we supply, this stage uses a combination of bag filters and scrubbers. Bag filters are exactly what they sound like: fabric bags that the gas flows through, and the tiny holes in the fabric catch particles as small as 1 micron—way smaller than what the human eye can see. We use special high-temperature fabric for the bags, since IBG can still be 100-150 degrees Celsius after primary cleaning, and the fabric has to hold up without melting or breaking. If a bag breaks (which is rare, but can happen from wear), we have a pressure monitoring system that alerts operators immediately, so they can replace it before bad gas gets through.
For sulfur removal, we use wet scrubbers that spray a mild, alkaline solution—usually limestone slurry or sodium hydroxide—into the gas stream. The sulfur compounds (hydrogen sulfide, in most cases) react with the solution, turning into a non-toxic, disposable salt that can be safely removed from the scrubber’s bottom. This is a key step because it reduces the unit’s emissions to meet global standards, and it also prevents corrosion in the downstream turbine. I remember a plant in Ohio that was flaring 120,000 cubic meters of BFG a day before installing our IBGRU; after the scrubber system, their sulfur emissions dropped by 92%, which helped them avoid $1.2 million in annual fines from the EPA. That’s the kind of result that makes all the engineering work worth it.
Once the gas is cleaned, tested, and approved, it moves to the blending stage, and this is where the unit meets the power plant’s specific needs. Different turbines have different requirements for gas composition. A gas turbine, for example, needs a consistent mix of hydrogen, methane, and nitrogen to run efficiently—too much nitrogen, and the flame is too weak to ignite; too much hydrogen, and the flame is too hot, damaging the turbine. So we install a blending system that mixes the cleaned IBG with natural gas (or even another type of IBG, like COG, which has a higher energy content) to hit the exact ratio the plant’s equipment needs. This system is fully automated, using sensors that measure gas composition every second, and adjust the blending rate in real time. Operators can check everything from their control room—no need to manually adjust valves, which reduces human error. I’ve had plant operators tell me this automation cut their daily maintenance time on the gas feed system by 3 hours, which they can now spend on other critical tasks.
The final stage is delivery to the power generation equipment. The cleaned, blended gas is fed into the plant’s existing boilers or gas turbines, where it burns to produce steam or spin the turbine, generating electricity. Here’s the big win: this is all additional power, using gas that was previously wasted. For a 500 MW coal-fired power plant, installing a 100 MW IBGRU means they can generate 20% more electricity without burning an extra lump of coal. That’s a huge emissions cut—per kWh generated, using IBG reduces CO2 emissions by roughly 70% compared to coal, because we’re using gas that would otherwise have been burned and released as CO2 without any energy capture.
But IBGRUs aren’t one-size-fits-all. Over my 12 years in this industry, I’ve learned that the best units are tailored to the plant’s specific by-product gas. For a steel mill producing mostly BFG and COG, we design a blending system that mixes those two to hit the perfect energy content. For a waste-to-energy plant producing methane from decomposing waste, we add a drying stage to the treatment process, because that methane has extra moisture from the waste breakdown. We also consider the plant’s location: in areas with strict emissions rules, we add extra carbon capture modules that pull even more CO2 from the gas, so the plant can sell that CO2 for use in things like carbonated drinks or enhanced oil recovery.
Let’s talk about some common misconceptions I hear, because operators often come to me with these worries. First, they think an IBGRU is too expensive. Yes, the upfront cost is significant—we’re talking millions of dollars for a full unit, depending on size. But the payback period is usually 3 to 5 years, from the money saved on fuel, plus carbon credits many regions offer for reducing emissions. That Ohio steel plant I mentioned earlier, for example, paid back the unit’s cost in 3.8 years, and now they’re making an extra $800,000 a year from selling the additional electricity to the grid. Another misconception is that IBGRUs are complicated to operate. Modern units have remote monitoring, and our team provides 24/7 support—if a sensor alerts us to a small issue, we can usually fix it over the phone before the operator even notices a problem. We also offer training for plant staff, so they feel confident running the system without relying on outside help.
Safety is another big priority, and it’s something we build into every unit. IBG is flammable, so we install multiple safety systems: pressure relief valves that open if the gas pressure gets too high, flame arrestors that stop a flame from traveling back into the collection lines, and gas detection sensors that shut down the system if there’s a leak. We also design the units with fail-safes—if the power goes out, the system automatically switches to venting any excess gas to a safe flare, so there’s no risk of explosion. I’ve never had a safety incident with one of our units, and that’s not luck—it’s from decades of refining our safety protocols based on real-world operator feedback.
As the world shifts to lower-carbon energy, IBGRUs are going to play an even bigger role. The International Energy Agency (IEA) estimates that industrial by-product gas could supply 5% of global electricity by 2030, if we can recover more of it. Right now, we’re only recovering about 60% of IBG worldwide—most of the rest is flared or leaked. That’s a massive untapped resource, and as a supplier, our goal is to help plants capture every last bit of it. We’ve worked with steel mills, coal-fired power plants, waste-to-energy facilities, even chemical plants that produce by-product gas during fertilizer production. No matter what the source, the core process is the same: capture, clean, blend, deliver. But we tweak every step to fit the plant’s unique needs.
If you’re a power plant operator dealing with wasted by-product gas, tired of paying fines for flaring, or looking to cut your fuel costs and emissions, an Industrial By-product Gas Recovery Unit could be exactly what you need. We’ve installed over 150 units across North America and Europe, and every one is built to last 20+ years with minimal maintenance. If you’re ready to stop wasting a valuable resource and start turning your by-product gas into profit and lower emissions, we’re here to help.
I’ve seen firsthand how these units change operations for the better: one plant in Pennsylvania went from flaring 80,000 cubic meters of gas a day to generating 25 MW of additional power, enough to power 18,000 homes. Another steel mill in Germany cut their emissions by 12% in two years after installing our IBGRU. These aren’t just numbers—they’re real impacts: lower energy bills, cleaner air, and a more efficient way to use industrial resources.
If you’re interested in learning more about how an IBGRU could work for your power plant, or want to discuss your specific by-product gas needs, we encourage you to reach out for a consultation. We’ll come to your facility, do an assessment of your gas streams, and put together a customized plan that fits your budget and goals. There’s no one-size-fits-all solution, but there is a solution for every plant with wasted by-product gas.
Small Air Separation Unit References
IPCC. (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press.
International Energy Agency. (2022). Global Energy Perspectives: Pathways to a Net-Zero Emissions System. IEA Publications.
U.S. Environmental Protection Agency. (2020). Industrial By-Product Gas Recovery and Use: Technical Assessment Report. EPA Office of Air and Radiation.
Xinxiang Jiale Intelligent Equipment Co., Ltd.
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