Virginia-based firm Cogent Energy Systems,’ new ionic gasification technology could be the perfect fit for small-scale waste to energy applications and even stabilise decentralised microgrids with dispatchable power.
Large waste-to-energy facilities have existed for decades, but technology that allows for economic recovery of energy from waste on a small scale – less than five tonnes per day, for instance – has remained elusive. Founded back in 2012, Cogent Energy Systems has spent the past five years developing a process to do just that, and they’re nearing the finish line in their effort.
“We came upon a technology at Idaho National Laboratory that was being used to create nano-particles,” explains Douglas Russell, Chief Business Development Officer at Cogent Energy Systems. “It was a modular hybrid plasma technology that formed the core of that gasifier application, and through discussion with the inventor, Dr. Peter Kong, we came to realize that the same basic concept could be applied to gasify waste materials for energy recovery applications. We saw an unserved market – how do you turn biomass or virtually any waste into usable products – at a small scale.”
The resulting proprietary ionic gasification process – embodied in the company’s HelioStorm Gasifier – involves the direct-contact processing of waste inside an active plasma field at temperatures of 3,000 to 10,000 degrees Celsius. According to the firm the result is a clean, high-energy synthesis gas (or “syngas”) that can be used to make many valuable end products including electricity, hydrogen, liquid fuels, and chemical precursors.
“We use multiple stacked modules to create a long, stable plasma processing zone that completely fills the interior of the gasifier ,” Russell tells WMW. “Feedstock drops directly into the ultra- hot reaction zone where it is vaporized into a clean carbon monoxide–hydrogen syngas. Third party verified tests showed that it is almost entirely free of long-chain hydrocarbons and contaminant chemicals.”
Russell continues: “The modular design of the system enables an energy cascade that reduces power consumption and results in surplus power . This is critical because previous attempts at small-scale WTE have often fallen victim to high electricity requirements sapping their output levels.”
According to Russell there are no signs of furans, dioxins or similar pollutants, and the oxygen starved process prevents the formation of nitrogen and sulfur oxides that could cause problems for downstream equipment. He also says that there is little need for cleanup of the gas beyond a dry scrubber, depending on its end use.
In the Navy
Cogent’s engineering partner, Hanover, New Hampshire-based Creare LLC, recently secured a Small Business Innovation Research (SBIR) Phase II grant from the US Navy to fabricate a complete small-scale waste to energy system using Cogent’s HelioStorm technology.
The first phase was conducted on paper and involved fully designing the system and scoring the various components. Key factors were the need to keep the physical footprint and energy consumption as small as possible to keep net energy production as high as possible while maintaining flexibility for different deployments.
Phase II will include fabricating and operating the actual system. The system is expected to be capable of cleanly converting up to 3.5 ton per day of mixed waste into energy-rich syngas. The syngas will then be directly combusted in standard military generators to produce almost 800 kWh of net electricity per tonne of waste processed. The electricity generated will be available on-site for general use at a base or naval operation.
“The original call to which our partner Creare responded was for mobile operations, but the initial deployment will likely be on a naval base for quality control. The request for proposals was to transform at least 1200 lbs (545 kg) of waste per day and do so in a way that is energy neutral. Phase 1 which we completed in January 2017 showed that the system should be capable of handling up to 3.5 ton per day and be energy positive.”
While the company originally embarked on developing the technology with the waste-to-electricity pathway in mind, it soon saw that the “magic” of what it does is in the gasifier itself.
“Let’s let the market decide on the application,” says Russell. “At the end of the day we’re a gasifier company and we produce the centre piece of what can be used in many configurations. Why would we want to limit it just to electricity? Why not look at the opportunity to produc fuels or chemicals as well? That’s certainly an area where we think there’s great potential.”
Further to the flexibility of the uses to which the syngas can be put, the company says that the system is also extremely flexible when it comes to the type of materials it can process.
“We’ve tested many types of materials from biomass such as hybrid poplar, bio-oil from pyrolysis, and simulated municipal solid waste,” explains Russell. “What we’ve found with all of these is that we get a very, very clean syngas that is 99.6% free of any kind of long chain carbon molecules. This level of purity makes it possible to go from feedstock to final product in one step, thereby opening the door to operate at small scale.”
When it comes to biomass, the firm was recently awarded a U.S. Department of Energy Small Business Voucher (SBV) grant.
“The SBV grant will enable us to work with the Biomass Feedstock National User Facility (BFNUF) at Idaho National Laboratory (INL) to optimise feedstock preparation. We’ll find out how best to prepare municipal solid waste for processing in our gasifier. Previously, we’ve proven that it works with particle sizes of around half an inch (13mm) and a moisture content of up to 50%. By and large the feedstock preparation needed is minimal,” says Russell.
Kevin Kenney, the director of the Biomass Feedstock National User Facility, adds: “Our researchers can identify important biomass variables such as particle size, composition and flowability. Our researchers understand connections between material properties, processing conditions and feedstock quality which will allow us to align feedstock characteristics with Cogent’s HelioStorm gasifier in a manner that will enhance reliability and optimise performance.”
Further to the company’s collaboration with BFNUF, in May of this year, Cogent won a competitive selection process to work with researchers at the Energy Systems Integration Facility (ESIF) at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) located in Golden, Colorado.
This collaboration will enable it to demonstrate the HelioStorm gasification system in ESIF’s simulated microgrid environment. This is Cogent’s second partnership with NREL following an earlier agreement for testing bio-oil based synthesis gas produced by the HelioStorm gasifier.
“Waste to energy can be an important part of small-scale and microgrid energy systems,” explains Bryan Hannegan, former Associate Laboratory Director for energy systems integration at NREL. "This collaboration at the ESIF supports our mission to advance the critical science and technology needed to modernise our nation’s electricity grid infrastructure for a more secure and resilient energy future."
Cogent's technology was chosen from a large pool of applicants as part of NREL's search for high impact projects that address the challenges of grid modernisation in the US. The project will show how best to integrate waste to energy with multiple other technologies such as solar power, wind power and energy storage in a microgrid environment.
An important goal for NREL is to find technologies that are scalable and can offer valuable lessons for national implementation. The flexibility and modular nature of Cogent’s gasification technology allows it to meet this goal.
“Cogent’s HelioStorm gasifier unlocks the door to 24/7 on-demand electricity in microgrids while helping solve waste disposal issues,” commented Dr. Abraham E. Haspel, CEO of Cogent Energy Systems.
With decentralised energy and micro-grids offering the potential to distribute power to small communities in both the developing and developed world, Russell sees a wide range of scenarios in which small-scale waste-to-energy can contribute to microgrids, from isolated island communities to industrial complexes.
The microgrid project at NREL is slated to begin this summer and will see the installation of a HelioStorm-based system at the ESIF in early 2018. Performance will be validated using ESIF’s simulated microgrid test environment.
When it comes to the future for the company and its technology Russell is buoyant. “We’re looking at a number of potential commercial applications to process high value medical waste in a number of parts of the US and Canada in the next nine months to one year. We’re hoping that by the end of 2018 we’re going to be a long way down the road.”
He adds that he expects the waste-to-energy installation with the US Navy to be proven within around 18 months. He also sees a lot of potential opportunities coming from the biomass and microgrid collaborations.
“We can provide 24/7 dispatchable energy which can be turned on and off quickly. When the sun is shining and the wind is blowing you can rely on those sources, but when it’s not we can keep the grid going and get rid of waste at the same time. It’ll reduce the amount of energy storage needed and increase the stabiblity of the microgrid,” says Russell.
“The world is moving in the direction of distributed energy. We feel that we have a breakthrough in how waste to energy can be part of that smaller scale environment. This whole area of ‘small’ is very exciting and we’re looking forward to talking with people about any number of applications with different feedstocks and different end products,” he concludes.