There has been a lot of buzz about dual-fuel engines and other machines that can use field gas as a fuel to save on diesel costs and emissions. But not all gas produced in oil and gas fields is usable.
So-called “waste gases” with very low Btu counts exist in many industries and are often released as pollutants since they can’t be burned. A company called Ener-Core has devised a unique solution to accelerate the natural oxidation of those gases so that they can be used to power machinery.
Making gases rust
The concept was started in the late 1990s by an engineer named Edan Prabhu, head of R&D for So Cal Edison, according to Alain Castro, CEO of Ener-Core. Prabhu was interested in examining alternative ways of using waste gases. “The challenge was getting energy out of gases that are very weak from a Btu perspective,” Castro said. “Sometimes these are gases that have lots of contaminants and impurities that wreak havoc on any kind of combustion device.”
Prabhu started experimenting with catalysts, but due to the impurities in the gases, the catalysts kept getting poisoned. But, over time, the engineering team at Ener-Core learned how to anchor an accelerated oxidation reaction without the need for any catalysts at all.
“We all know oxidation happens to virtually everything, including our own skin,” Castro said. “But, unfortunately, when it comes to greenhouse gases, our natural atmosphere simply takes way too long to oxidize them, and they linger in our atmosphere for 10 to 20 years before being fully oxidized.
“With Ener-Core’s technology, we create an environmental condition or atmospheric condition where the natural oxidation reaction happens in two to three seconds instead of 10 to 20 years. By doing so, we can use the heat energy that’s created by our accelerated oxidation reaction. One thing that many people, even engineers, don’t realize is that oxidation is exothermic—it gives off heat. But normally it’s such a slow chemical reaction that you really can’t tell,” he continued.
By 2007 Prabhu had obtained venture capital funding, and between 2007 and 2013 he put some engineering resources behind his concept, built prototypes and developed what is now called the “Power Oxidizer,” which takes low-quality gas, causes an oxidation reaction and releases energy in the form of heat.
“At the right pressure and temperature, we can optimize the speed of an oxidation reaction,” Castro said. “Oxidation takes forever in the atmosphere. If we go to higher pressure—4 atmospheres or so—and higher temperatures, we can get that reaction to happen at its optimal speed.”
Not only does the process prevent approximately 99.9% of the greenhouse gas from going to the atmosphere, but the energy released from the reaction can be used to power a turbine or boiler, he added.
The company recently announced a partnership with Hofstetter B.V., a specialist in flaring technology and degassing systems, providing Ener-Core, through its distributor, Holland Renewable Energy Technologies, access to significant European markets. Hofstetter has installed more than 1,600 flaring systems around the world.
“The Ener-Core Power Oxidizer is a revolutionary technology that greatly expands our offering for customers,” Andre Schoute, managing director at Hoftstetter, said in a press release.
Castro added that the company has gone “way beyond field trials” in other industries, outfitting old landfills, for instance. “For every active landfill, there are probably two inactive ones. The inactive ones have very poor gas quality because they’re not getting replenished with municipal waste. But one of the environmental issues is related to the fact that an inactive landfill continues to emit poor-quality greenhouse gases for another 50 to 60 years after it ceases to receive any more municipal waste. Despite these ongoing emissions of waste gases, the common thought is that once a landfill becomes inactive, you can’t run any kind of power generation on it because the gas quality goes way down.
“We’re actually operating on a landfill in The Netherlands that has been inactive for more than two decades, and we’re enabling that landfill to generate power (and revenues) for decades to come,” he explained.
The company is also in the process of installing a system in Orange County, Calif., on an inactive landfill that has been closed since 1996 but has needed to continue flaring its waste gases.
It has been a bit slower for Ener-Core to successfully enter the oil and gas industry, but it has partnered with Dresser-Rand to visit with “just a handful of first-tier oil and gas companies” to discuss possible applications, Castro said. “We’re entering into evaluation phases where the enthusiasm is very high, but what they want to do is deploy a few of these units on drill sites, in oil and gas refineries and potentially at various stages throughout the pipelines.”
One customer is a large oil producer. Like many upstream oil companies, it has to supplement its lowmethane waste gases with high-quality natural gas to be able to flare it. The company approached Ener-Core to find a better solution.
“Phase 1 was to complete a test at our facility at the University of California-Irvine,” said Mike Leone, market development manager for Ener-Core. “We trucked in large volumes of low-quality gases to simulate the gas composition from the drilling sites. That allowed us to prove that we can generate power from a very low-energy gas while also achieving the highest known emissions curtailment in the market.
“A typical gas engine needs a gas that is least 30% methane to operate properly, and we proved in that particular case that we can run our power station down to 7% methane. That’s a lot lower than anyone else has been able to generate electricity from,” he added. Oil companies currently spend money to flare their waste gases, and they can now use their waste gases to
produce clean electricity for their own site operations, he said. “For them it’s pretty much a no-brainer.”
Currently Ener-Core is structuring a plan to install one or two units in northern Alberta to prove that the units are rugged enough to withstand the region’s tough winters. Then it’s basically off to the races. “Virtually every drill site could one day have one of these power station units operating on it,” Castro said. “We’ve just been in shock to learn how common it is for oil and gas companies all over the world to be purchasing natural gas solely so that they can enrich the energy density of their waste gas, just to be able to burn it and comply with environmental regulations on emissions.”
The benefits are numerous. Not only do the systems monetize waste gases, but they also help operators comply with environmental regulations, which are becoming increasingly stringent in terms of flaring. “It’s an environmental solution with a real financial payback,” Castro said.
Dresser-Rand is the first licensee of this technology in the oil and gas industry, and the ultimate goal is to commercialize the technology through large, established companies that make turbines and steam boilers, he said.
“If you think about a gas turbine or a steam boiler, the first phase of both of those pieces of equipment is a combustor,” he said. “Combustors have been around for hundreds of years, and they’ve improved tremendously. However, the combustors limit the turbines, boilers and other energy equipment from being able to run on poor-quality fuels. Now we can retrofit our Power Oxidizer into these boilers or turbines to replace those combustors. We can then work with these license partners
as our commercial front end as our Power Oxidizer equipment is getting embedded into their turbines and boilers.”
Early conversations with Dresser-Rand customers have been very positive. “In every single meeting we’ve had with the operations directors who have authority over the entire supply chain, the typical response has been, ‘There are so many applications for this across our infrastructure!’ And their jaws drop,” Castro said. “We just think it’s a matter of time before this will become mainstream news.”
And given the current environment of low-priced oil, making operations more efficient and reducing operational costs becomes the name of the game. “Yes, we’re making their operations cleaner, and there’s a great public benefit for oil companies being able to report that they’re being more environmentally sustainable,” he said. “But just as importantly, we’re enabling them to
get their costs down, thereby gaining a competitive edge within their industries.”