Pre-processing and Conditioning of Coal/Biomass Mixtures for Simultaneous Co-Feeding Systems. By including the renewable component in the feedstock, coal-biomass gasification can potentially improve greenhouse gas (GHG) emissions compared to traditional feedstocks, while meeting the mitigation requirements for all other pollutants. In order to co-feed biomass effectively with coal, as well as transport and store large quantities of biomass at an energy producing facility, a considerable amount of pre-processing and conditioning may be necessary. An improved understanding of several aspects of coal/biomass feeds are needed to achieve efficient gasifier throughput.

NETL is seeking applications for R&D to prepare and characterize coal and biomass mixtures (e.g. briquettes, slurries or other uniform mixed fuels) to a form that is transportable, storable, and will accommodate direct co-feeding into gasification systems (i.e. through the same feed inlets) that operate at temperatures and pressures typical of commercially available coal-fired gasifiers.

Applications must address a combined fuel containing a blend of coal and biomass. Applications that address the preprocessing and conditioning of coal or biomass only are not sought.

Applications must develop and characterize multiple coal-biomass mixtures and types. The materials can be blended multiple ways, such as, but not limited to, briquettes, small particle mixes, and slurries. Applicants will develop blends of coal and biomass mixtures that will include at least one of the three major coal types: lignite, sub-bituminous and/or bituminous; and at least one of three biomass types: corn stover, wood (forest residue, manufacturing residue, or short rotation woody crop— e.g., poplar), and/or grass (switchgrass and mixed prairie grasses).

Each feedstock blend will include a specific biomass type mixed with a specific coal type at biomass concentrations of 10 wt.% and 30 wt.% (dry coal and dry biomass basis), at a minimum.

Characterization of the coal-biomass mixtures, such as, but not limited to, flow properties, stickiness, homogeneity, moisture content, particle size, shape, elasticity, and bulk physical properties (compressibility, heat transfer, friability), should be included in the study. Applicants should also consider several different methods of mixtures and blends of coal and biomass.

The applications should identify what systems can utilize the mixtures effectively (e.g. slurries or small particles for entrained reactors or briquettes for moving bed gasifiers). Gasifier throughput using different blends must also be considered. The process must demonstrate economic feasibility as well as the environmental impact generated from these processes.

Reactive Properties of Coal/Biomass Mixed Fuels. Coal/Biomass gasification can produce syngas for use in turbines for energy generation and in refineries for production of fuels and chemicals with reduced carbon emissions through the use of renewable energy sources. The preprocessing and conditioning necessary to co-feed these mixtures—such as torrefaction, briquetting, and pelletizing—can modify the kinetics and burn rates necessary to provide a clean syngas stream for use in power, hydrogen, fuels, and chemical production.

Chemical kinetics and reaction mechanisms, while available for many coals, are not established for a wide range of coal-biomass mixed fuels. Inputs for science-based computational codes are, in general, not comprehensively known for coal-biomass mixed fuels of various types. Prediction of unreacted carbon in slag from gasification is difficult, affecting the ability to dispose of or economically use the by-products. Modeling ability for prediction of minor components such as pollutants and contaminants in gasification systems is limited.

There is a need for high temperature, high pressure particle flow reaction measurements to determine chemical reaction rates, morphology changes and char/slag formation with residence times corresponding to entrained reactors. Advanced particle scale models are needed to accurately address global kinetics in entrained flow situations, swelling, pyrolysis, heterogeneous reactions, particle clusters and coupling to hydrodynamics.

NETL is seeking applications are sought that define and measure key reactive properties of a wide variety of relevant mixed coal-biomass fuels that can be measured in small-scale laboratory experiments and/or used in science-based computational models to confidently predict their physical and chemical behavior in gasification systems.

The experiments/models must, at a minimum, characterize the chemical kinetics and reaction mechanisms of coal-biomass mixed fuels. The models developed must incorporate a combination of the kinetics of coal as well as conditioned biomass products such as pellets or briquettes. Applicants are to define a test matrix of coal-biomass co-feeds that will include at least one of the three major coal types and at least one of three biomass types noted above.

Each test will include a specific biomass type mixed with a specific coal type at biomass concentrations of 10 wt.% and 30 wt.% (dry coal and dry biomass basis), at a minimum, and may include other combinations not exceeding 50 wt% biomass.

The pressure/temperature conditions of the tests will be those that are appropriate to a commercially-available coal gasification systems configured to co-produce power and liquid fuels from coal-biomass mixtures.

Design concepts for Co-Production of Power, Fuels, and Chemicals. Coal-biomass gasification can produce syngas which can be further utilized for the co-production of power along with hydrogen, fuels, and chemicals. However, preliminary and/or conceptual designs for integrated, economically viable co-production facilities and/or processes are lacking. In particular, conceptual designs incorporating advanced concepts (i.e., oxygen production, feed systems, warm gas cleanup, membrane separation, advanced turbines, etc.) have received minimal attention, NETL notes.

NETL is seeking applications for the development of design concepts, incorporating advanced technologies, for the integrated, economically viable co-production of power and hydrogen, fuels, or chemicals from a single facility equipped with carbon capture and storage.

The deliverables from these projects will be preliminary conceptual designs, techno-economic analyses that predict plant efficiency and cost of produced products, and environmental studies. These studies are to assess the potential impacts of integrating emerging technologies in the co-production of power, fuels, and chemicals from coal or coal-biomass mixtures. They will help to establish costs, risks, potential economic performance, and environmental impacts of such facilities and identify commercial/market potential for their products.

Designs are to incorporate coal-biomass co-feeds that will include at least one of the three major coal types and at least one of three biomass types. The coal biomass feedstock concentration must be in the following range: biomass concentrations of 10 wt.% to 30 wt.% (dry coal and dry biomass basis). For comparison purposes, designs concepts shall also incorporate coal-only feeds in both an electricity only mode as well as a co-production mode.

DOE/NETL may utilize the results of these studies to develop comprehensive system studies and/or models as well as identify future RD&D activities. Each recipient will be required to develop four separate design concepts and studies for the integrated production of power, fuels, and chemicals. These concepts are:

1. Power & hydrogen production;
2. Power & fuels production;
3. Power & petrochemicals production; and
4. Power & agricultural chemicals production.

The proposed design concepts must demonstrate a power output greater than 50% of the total energy output of the co-production plant and must be equipped with carbon capture and storage. Design cases are to be based upon currently available commercial-scale gasifiers.

Conceptual designs are to consider all of the major unit operations in the envisioned co-production facility/process. Time and funding may limit the extent of the design analysis and include assumptions related to specific plant/process operations, and the assumptions should be clearly identified.

Processes and operations included in a process design flow sheet may include (but are not limited to, and do not require all of):

• Coal-biomass feedstock preparation;
• Feedstock conditioning and handling;
• Gasification;
• Gas cleanup;
• Membrane separations;
• Fischer-Tropsch;
• Power production; and
• Co-product production, etc.

The process flowsheet must include a CO₂ mitigation strategy that captures and sequesters or beneficially utilizes at least 75% of all CO₂ emitted from the overall process.

A key component of the conceptual design shall include an economic assessment, identifying potential savings in cost of electricity relative to operating in a co-production mode compared to operation in an electricity only mode.

DOE intends to limit the ability of recipients under Topic Area 3 to copyright generated information whenever said information is determined by DOE to be essential to its ongoing efforts to develop publicly-available information.