Ener-Core Inc. has engineered a solution that uses lower quality methane sources. “Gradual Oxidation” is unique for the low quality fuel capability, but also for its ability to operate at pressure.
Methane is a greenhouse gas which in its purest form is an important energy source. The best methane, which is commonly found in oil and gas fields, is cleaned and conditioned to natural gas. Processed methane can be used in traditional reciprocating engines, gas turbines and boilers to meet the growing electricity and heat needs around the world.
As regions globally target more local energy resources and significant decreases in greenhouse gas emissions, their focus on using these low quality methane sources has increased. The problem is that low-quality methane sources can be difficult to improve to natural gas quality (pipeline quality) so that traditional technology can use it to generate heat or power. As a result, instead of viewing this methane as an energy resource, they see it as a problem. The typical first choice – if the gas can’t be used to generate power with traditional technologies – is to flare the gas which helps mitigate the greenhouse gas impact, but adds to air pollution and wastes the resource. Their other choice is to vent the gas, which also wastes the resource and pollutes the environment even more than without a flare.
Now a question must be put forth: How much of this dilute methane and gas emissions exists? The U.S. Environmental Protection Agency (EPA) publishes a summary report on the historical and projected estimates of non-carbon dioxide greenhouse gases, including methane.
The table above shows the methane emissions from different sources growing to about 400 millions of metric tons by 2030. The 2030 projections are over a 20 percent increase from the 2005 levels.
In order to take advantage of this opportunity, Ener-Core Inc. engineered a solution that used these lower quality methane sources. This approach differed from traditional engineering solutions, where manufacturers found ways to extend the operating range of its natural gas engines and turbines to include methane gases which were a bit lower in energy content than natural gas. Ener-Core instead developed and patented its own oxidizer technology which focused on
using a variety of fuel sources, including otherwise unusable low-quality fuel. The Ener-Core oxidation process – known as
“Gradual Oxidation” – is unique not only for the low quality fuel capability, but also for its ability to operate at pressure, allowing power to be generated from the lowest quality fuels. In addition, the power is generated with low associated emissions as NOx levels are fewer than 1 part per million.
Gradual Oxidation works by controlling the continuous energy release from the methane oxidation reaction. The chemical reaction energy is released at the operating pressure and temperature of the matching gas turbine generator. The Ener Core Gradual Oxidizer controls the gas feed rate to maintain temperature control needed to continuously power the gas turbine generator, but it avoids the high peak temperatures of traditional combustion since it does not form a flame. Without the flame formation, it avoids creating NOx (oxides of nitrogen) thus it does not form the precursor to ozone and avoids a key component to smog. In addition, the chemical reaction time is controlled between 1 and 2 seconds, which allows the destruction of carbon monoxide and volatile organic compounds.
The Gradual Oxidizer does not have the operational issues that traditional combustion experiences with using a wide variety of fuels to limit NOx emissions and balancing temperatures and stability with acoustics. The Gradual Oxidizer operates on fuel which is about 15 Btu/scf, or 1.5 percent the strength of natural gas. Most fuels would need to be diluted down to this low quality prior to distribution within the oxidizer. The Ener-Core Gradual Oxidizer can convert low concentration fuels to power while offering emissions much lower than the traditional gas turbine.
Ener-Core currently matches its Gradual Oxidation technology to two turbine sizes. A 250-kiloWatt (kW) output system, named the FP250, integrates the Gradual Oxidizer with a FlexEnergy 250 kW microturbine. The 1.85-megaWatt (mW) output system, named the KG2-3G/GO, integrates the Gradual Oxidizer with the latest production version of the Dresser- Rand 2 mW KG2-3G gas turbine.
Ener-Core commercialized the FP250 in 2013 after a successful demonstration program with the Southern Research Institute and the U.S. Department of Defense at the Fort Benning Army Base landfill. Also, Ener-Core shipped an FP250 to a leading Dutch landfill company this past November. At this time, Ener-Core is developing a 2 mW class conjunction with Dresser- Rand with the goal of being sold jointly by Ener-Core and Dresser-Rand in 2014.
Ener-Core sees a unique opportunity in producing power with dilute methane fuels. Much of this gas has little or no
value, since this gas is too weak and therefore low in energy content. The weakest of this gas, such as ventilation air methane, is much weaker than natural gas and is actually closer to zero energy than it is to pipeline gas.
So how much power could be generated with the Ener-Core Gradual Oxidizer and a matched gas turbine using this low or zero value energy source? According to the U.S. EPA methane data for coal mines and landfilling of solid waste,
the total potential for these two sources is more than 30,000 mW by the year 2030. Of course, the actual power that could be generated is dependent on the percentage of these emissions that are collected and delivered to the Ener-Core system.
The table to the left shows the United States EPA data for landfill emissions (released in 2013). The United States collects about 60 percent of the methane generated at landfills, with about 30 percent of it being converted to energy and about 30 percent wasted through flaring.
Ener-Core sees the global waste gas market as constantly growing. Also because of increasing populations and growing landfills, the expansion of oil and natural gas drilling sites, coal mines and other methane sources, there is ample opportunity for Gradual Oxidation to expand and play a pivotal role in the future. The demand for electricity is growing globally and communities are seeking to reduce air pollution, especially from major sources and flares as countries understand the harmful impacts of pollution. Ener-Core is deploying its technology to capitalize on this growing global market.