Clean Hydrogen & Negative CO2 Emissions Emissions focuses on designs and strategies for modular gasification-based systems enabling negative lifecycle emissions of greenhouse gases. Biomass can have an important role in reducing carbon intensity of fossil fuel-based systems, as can application of advanced technologies integrating carbon capture. Likely approaches to be considered include co-utilization of biomass with wastes as gasification feedstocks, integrated or pre-combustion capture of CO2 especially facilitated by gasification, and innovative technological approaches or combinations of technologies enabling extensive greenhouse gas reductions of modular gasification systems.
Interest in the concept of co-feeding biomass to fossil fueled plants including advanced gasification-based plants such as IGCC power plants, emerged from the idea that mixed feedstocks with biomass systems could become part of an early compliance strategy for carbon reduction, particularly across the large existing installed base of coal-based power plants. Recognizing that large biomass-alone power plants are constrained by low biomass energy density, feedstock water content, feedstock collection and preparation, and seasonal/regional feedstock availability, waste-biomass systems could benefit from the stability of a multiple feedstock mix, adding tractable amounts of biomass as constrained by technical/performance requirements and biomass availability.
Co-feeding biomass can reduce the carbon intensity of power generation and other fossil fuel consuming processes, but to achieve zero or negative lifecycle greenhouse gas emissions in these power plants some degree of carbon capture must be implemented. Gasification systems have the advantage considering that CO2 in typical syngas is much more concentrated and pressurized than the CO2 in the flue gas of combustion-based plants. Both concentration and pressure aid in separating CO2 from the syngas. Also, innovative modular gasification and water gas shift reactors afford opportunities for in situ oxygen production and gas separations which can facilitate or reduce the costs of CO2 capture.
Thermochemical co-conversion cycles consisting of 1) gasification-based electricity production with carbon capture and storage, and 2) long-chain hydrocarbon fuels production via gasification and the Fischer–Tropsch process (or alternatives) with carbon capture and storage, or both (polygeneration) have been strongly advocated as viable/accommodating process systems for a feasible commercialization strategy for carbon-negative energy. The NETL Gasification Program accords with this strategy with its recent efforts in modular gasification-based systems for power production, its work in syngas-based fuels production, and many projects in the portfolio considering biomass additions to the feedstock mix for greenhouse gas reductions in power generation and fuels production, and others considering techno-economic advantages of polygeneration systems. R&D of these systems should continue towards demonstration of technical feasibility at commercial scale and reduction of investment risk, which have been identified by the R&D community as key research and policy needs in carbon negative energy systems development.
In the biomass gasification field, moving bed or fixed bed gasifiers and fluidized bed gasifiers comprise the vast majority of gasifiers used, given their relative flexibility in handling varying feed streams and suitability to the sizes needed for typical applications. However, high-temperature, oxygen- or steam-blown, pressurized, entrained-flow gasification of multiple biomass-containing feed streams has been advocated as an important area of focus for R&D, considering the higher efficiency and reaction intensity of entrained gasification. NETL has begun to make inroads into this area as it supports R&D of high-pressure modular gasifiers (mainly entrained flow type), high-pressure feeding of lower quality fuels including biomass/waste blends, lower cost air separation for modular systems, and so on. The R&D strategy is to continue pursuing gasifier technology for higher efficiency gasification of waste/biomass blends and reduction of those technology costs. This will strongly enable negative greenhouse gas emissions technology in gasification systems.
The following projects from 2022 focus on cost reductions in clean hydrogen production from efficient gasification systems to make progress toward DOE’s Hydrogen Shot initiative’s cost goal of $1 per one kilogram of clean hydrogen:
Fluidized-Bed Gasification of Coal-Biomass-Plastics for Hydrogen Production—Auburn University is studying gasification of coal/plastic/biomass mixtures in steam and oxygen environments, characterizing the thermal properties of ash/slag and investigating the interaction between slag/ash and refractory materials, and developing process models to determine the technology needed for syngas cleanup and removing contaminants for hydrogen production.
Enabling Entrained-Flow of Gasification of Blends of Coal, Biomass, and Plastics— The University of Utah is enabling entrained flow co-gasification of biomass and waste plastic by creating slurries of pulverized coal, biomass pyrolysis liquids, and liquefied plastic oil. Conventionally, high-pressure, slurry-fed, oxygen-blown entrained-flow systems are not generally amenable to waste and biomass gasification, but this approach is a novel and elegant solution to that problem. Challenges include formulating coal-biomass-plastic mixtures that produce a stable slurry suitable for pumping to high pressure, designing and testing a novel burner (“hot oxygen burner”) to effectively atomize the mixed feedstock slurry in a pressurized gasifier, and acquiring performance data using Utah’s one ton per day pressurized oxygen-blown gasifier.
Development and Characterization of Densified Biomass-Plastic Blend for Entrained Flow Gasification—The University of Kentucky has been developing and studying a coal/biomass/plastic blend fuel for oxygen-blown, slurry feed gasification. They have densified biomass and encapsulated biomass in plastic to improve gasification characteristics and have demonstrated viable coal/biomass/plastic solid fuel slurry for gasification in their versatile entrained flow gasifier.
Performance Testing of a Moving-Bed Gasifier Using Coal, Biomass, and Waste Plastics to Generate White Hydrogen— Electric Power Research Institute, Inc. (EPRI), is studying combinations of coal, biomass, and plastic waste blends in formulation of feedstock pellets for moving-bed gasification to produce hydrogen.
Optimization of Coal Waste/Biomass Gasification for Hydrogen Production—Microbeam Technologies Incorporated is studying waste coal and biomass feedstocks properties and modeling slag/ash behavior to improve the ability to manage fluctuations in these feedstocks, thereby increasing availability and efficiency of gasifiers and driving down the cost of hydrogen. Their approach involves utilization of MTI’s Novagen™ software product to manage feedstock properties and to optimize gasifier operations online.
A Mid-Century Net-Zero Scenario for the State of Wyoming and its Economic Impacts—In this project, The University of Wyoming is examining the economic impact of fossil energy production in Wyoming and providing various predictions for future energy mixes to achieve net-zero emissions, focusing on critical aspects to reduce carbon emissions and facilitating the deployment of a clean hydrogen industry.
Clean Hydrogen from High-Volume Waste Materials and Biomass
The following projects, which commenced in late 2022 to early 2023, concern technology development supporting production of net-zero carbon hydrogen from blended feedstocks that include biomass, waste coal, waste plastics, and municipal solid wastes, with carbon capture included in process systems:
Advancing Entrained-Flow Gasification of Waste Materials and Biomass for Hydrogen Production—This University of Utah project is studying gasification of blends of biomass and high-volume waste materials (in the form of various slurried mixtures of coal, biomass liquid, and waste plastic oil) to produce hydrogen and improve feedstock preparation and feeding to enhance gasifier performance and conversion. A 1-ton/day pressurized, oxygen-blown entrained-flow gasifier outfitted with a new flexible fuel gasifier burner based on proven hot oxygen burner technology is being utilized, which should help improve feeding flexibility, feed quality, and cost performance.
Fluidized Bed Gasification for Conversion of Biomass and Waste Materials to Renewable Hydrogen—A Gas Technology Institute (GTI)-led team is evaluating the chemical kinetics and gasification behavior of biomass and waste material feedstock blends, as well as a safe and reliable feeding mechanism for those blends into GTI's U-GAS® pilot-scale gasifier. This is to establish the basis for development of a 5–50 megawatt-scale hydrogen production plant using the U-GAS technology fed with the unusual combination of biomass, waste plastic, and municipal solid waste (MSW).
Hydrogen Production from High Volume Organic Construction and Demolition Wastes—The Energy and Environmental Research Center at the University of North Dakota will study gasification of construction and demolition debris-containing treated lumber to produce clean hydrogen, while addressing the challenge of simultaneously capturing/storing arsenic contained in this contaminated feedstock. Integrated system design for an oxygen-blown fluid-bed gasification system, including gasifier structure and operating conditions, unit materials, tar cracking, and gas filtration is in scope.
Onsite NETL Research— Clean Hydrogen & Negative CO2 Emissions
NETL’s R&IC’s work includes analysis of gasification of alternative feedstocks for clean hydrogen production with sustainable CO2 emissions:
Hydrogen Shot Fact Sheet:
Fact sheet about the U.S. Department of Energy's Hydrogen Shot, which seeks to reduce the cost of clean hydrogen by 80% to $1 per 1 kilogram in 1 decade.
Other key technologies within Gasification Systems include the following: