Upcycling Plastic and Coal Wastes into Syngas by Steam Gasification
For presention at the AIChE Annual Meeting, Orlando, FL, November 5-10, 2023.
Natesakhawat, Sittichai↗
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Microwave Catalytic Gasification of Mixed plastics and Corn Stover for Clean Hydrogen Production
For presentation at the AICHE Fall 2023 National Meeting, Orlando, FL, November 5-10, 2023.
Abedin, Ashraf↗
Capabilities Development at the University of Texas at El Paso for Hydrogen Generation Research and Education
Gasification-based systems have recently received much attention due to their capability of converting wastes into useful fuels. The gasification of biomass, municipal solid waste (MSW), plastics, and other sustainable resources has shown promise in hydrogen production. When coupled to a CCU or CCS unit, these systems have the potential to achieve carbon neutrality or carbon-negative emissions. In addition, these systems have an edge over conventional incineration or landfill systems by reducing greenhouse gas emissions and recovering useful energy. However, the gasification of MSW and other wastes is still in its early stages. In particular, co-gasification of wastes with biomass has significant unknowns in optimizing the reaction kinetics, operability, design and performance improvements. Currently, Supercritical Water Gasifiers (SCWG) and Plasma Gasifiers are the major systems that are capable of producing high hydrogen amounts from Biomass and MSW, respectively. However, both systems have high capital and operating costs, adversely affecting efficiency and the hydrogen production cost. Additionally, due to lower temperatures, SCWGs are prone to tar formation and fouling in the heat exchangers. Hence, there is a need to look for alternative solutions for MSW and biomass gasifications, particularly in co-gasification. The current effort aims to develop a strategic plan to establish a sustainable gasification facility for hydrogen research at the University of Texas at El (UTEP). A major part of this effort involves an extensive literature survey to identify technological gaps and potential areas of interest. Several concepts were developed in accordance with the current demands from the literature survey. Based on the concepts, a center-wide capability assessment was conducted to measure the current capacity and feasibility of establishing hydrogen research. Afterward, a strategic research plan was developed, and a list of required resources was made for the expansion of hydrogen research at UTEP. In addition, successful partnerships with the local county and the city were developed to pursue hydrogen research. The strategic goal setting and planning of UTEP Aerospace Center resulted in securing $2.5 million in external support to expand the hydrogen research during the project performance period. In addition, during the project period, a course in Hydrogen Energy Systems was developed to expand the energy curriculum at the UTEP Aerospace and Mechanical Engineering Department. The course focused on hydrogen production, storage, supply and delivery and application. The cross-listed course was offered at both undergraduate and graduate levels during the Spring 2024 semester and had 27 enrolled students. Moreover, the students supported under this award were trained in gasification process modeling, CAD, CFD and FEA during the project period. The training enabled the students to move into new projects to support gasification design, integrated gasification combined cycle process plant analysis, gasifier structural and operational analysis, and digitally threading the systems.
08 HYDROGEN↗
Performance Testing of a Moving-Bed Gasifier Using Coal, Biomass, and Waste Plastic Blends with Washed and Unwashed Legacy Coals and Other Waste Fuels to Generate White Hydrogen
The objective of this effort, primarily funded by the United States Department of Energy (DOE), and led by the Electric Power Research Institute, Inc. (EPRI), with support by Hamilton Maurer International (HMI) and Sotacarbo S.p.A. (Sotacarbo), has been to qualify coal, biomass, and plastic waste blends based on performance testing of selected fuel pellet compositions in a pilot-scale updraft moving-bed (UDMB) gasifier. The testing provided relevant data to advance the commercial-scale design of the moving-bed gasifier to be able to successfully use these feedstocks to produce hydrogen. In particular, the effects of waste plastics on feedstock development (i.e., blending and pelletizing) and the resulting products (i.e., syngas compositions, organic condensate production, and ash characteristics) are the focus. The gasifier used for testing is HMI’s moving-bed gasifier, which has been proven capable of gasifying nearly all coal ranks. It has also shown the ability in prior testing work to gasify wood chips (biomass). However, mixtures of these fuels with plastic wastes have not been prepared and gasified together. The three feedstocks were densified and pelletized by California Pellet Mill (CPM) to meet the feedstock size required by Sotacarbo’s 30mm ID UDMB gasifier, under contract to HMI. The technical tasks and results from this two-year research project included: (1) Feed Procurement and Preparation: Nine different tri-fuel pellets were prepared from varying compositions of fresh mined PRB coal, corn stover biomass, and car fluff waste plastics. Tri-fuel pellets were produced by CPM and shipped to Sotacarbo’s test facility in Carbonia, Sardinia, Italy. (2) Test Plan Development: A test plan was created to define the test runs to be performed. The test plan detailed the different UDMB gasification tests to be performed in Sotacarbo’s 12-inch ID pilot scale gasifier, the process monitoring instrumentation used, and the extractive samples recovered for analysis of the total gasification process mass and energy balance. (3) Gasifier Testing: Nine different gasification runs were performed in the pilot-scale gasifier at Sotacarbo using nine different fuel feedstock compositions generated from varying mixtures of PRB coal, biomass, and plastic wastes. The testing generated performance data on gasification reaction efficiency and performance, yielding relevant data for models used to scale up the gasifier design. This task also included work to refurbish and reassemble the pilot gasifier at Sotacarbo and perform a baseline 100% PRB coal run. (4) Data Analysis and Reporting: Review of the data, determination of figures of merit, and interpretation of the results are reported in the project’s final report, published in March 2024. The results show that all tri-fuel pellets gasified well and maintained structural integrity throughout the gasification process. The syngas generated can be shifted to hydrogen by using commercial syngas shifting technologies. (5) High Fidelity computational fluid dynamics (CFD) Simulation: The National Energy Technology Laboratory (NETL) team performed CFD simulations of the UDMB gasifier for two of the tri-fuel pellets gasified in Sotacarbo’s pilot scale gasifier. The kinetic mechanisms for the pyrolysis of each constituent, PRB coal, corn stover biomass, and waste plastics are based on thermogravimetric analysis performed by Sotacarbo. The gasification model was validated by comparing the predicted syngas composition at the exit of the gasifier with the measured syngas composition. In addition, the reactor’s measured internal temperature profile agreed well with the predicted internal reactor temperature profile. These results validate that the model can be used to predict the performance of the updraft moving bed gasifier for different feedstocks and operating conditions. This paper summarizes the results of the completed work in which the pelletizing procedure was validated to ensure the viability of the tri-fuel pellets for the gasification runs performed at Sotacarbo’s 30 mm UDMB gasifier. The gasification performance data from this series of nine runs will enable modeling of a full-scale HMI industrial scale gasifier supporting both combined heat and power, and Hydrogen production from coal (both fresh mined and legacy) combined with various biomass and waste plastics. Additionally, plans and progress on a follow-up project, being executed by the same project team, will be presented. In this project, a total of twenty (20) different feedstocks are being prepared from varying compositions of biomass (both woody biomass and corn stover) with a mixture of legacy coal waste, plastic waste, and refuse-derived fuel (RDF). The testing will provide information on gasification reaction efficiency/performance, yielding relevant data for models used to scale up the gasifier design to 50 megawatt electric (MWe) (equivalent hydrogen production). Tests will also be performed on a bench-scale fluidized-bed gasifier for comparison purposes. The results of this testing will be used to specify the range of feedstock blends that can be successfully gasified as well as quantify gasifier outputs based on specific blends.
08 HYDROGEN↗
Staged OMB for Modular Gasifier/Burner
The goal of this final project report is to comprehensively summarize the work conducted on project DE-FE0031506. In accordance with the Statement of Project Objectives (SOPO), the University of Kentucky Center for Applied Energy Research (UK CAER) (Recipient) has developed a staged opposed multi-burner (OMB) gasifier, scaled down from a commercial gasification technology to utilize coal slurry as feed for the high-temperature gasification. The project involved the design, fabrication, commissioning, parametric testing, and performance validation of the entrained gasifier with multiple burners to narrow the major near-term technical gaps that impede the application of small-size gasification by modularizing the system. Project results verified the UK CAER approach to address the major technical challenges on the gasification modularization for a distributed application at a small scale of 1-5 MWe, while maintaining advantages in cost and flexibility, which include: 1) a cost-effective burner configuration to provide high flexibility in both load and fuel feed; 2) the modularized staged-OMB to provide better gasification performance such as a desired temperature profile, better fuel conversion, better gasification efficiency, and long lifetimes of the refractory wall and burners; and 3) load control simply through changing the number of burners firing. UK CAER’s staged gasifier configuration, fuel blend performance, and economic evaluation shows promise, as summarized in this report, as an effective means for improved gasification efficiency with reduced operation cost and process complexity.
01 COAL, LIGNITE, AND PEAT↗
Chapter 6: Recycling Plastic Waste to Produce Chemicals - A Techno-Economic Analysis and Life-Cycle Assessment
This study presents the results of a preliminary assessment on the technology, economics, and sustainability of using waste plastics as a feedstock to produce low molecular weight olefins via pyrolysis and gasification pathways. We also studied the formation of formaldehyde - an important polymer precursor - via the gasification of waste plastics. Process pathways for recovery of ethylene and propylene and production of formaldehyde from a simulated mixed plastic waste were constructed based on literature data. They included direct and indirect pathways based on either gasification or pyrolysis as the primary conversion step. Results of these studies have shown that significant economic challenges exist of producing olefins via pyrolysis and gasification, with the latter pathway especially difficult. Base costs of pyrolysis naphtha from waste plastics are higher when compared to the same material produced from fossil feedstocks. Base olefin costs for one direct route are two times higher than comparable costs from steam cracking of fossil naphtha. These costs are driven primarily by feedstock costs; some pyrolysis scenarios become more economically feasible when very low feedstock costs are used. Similarly, for gasification, the cost of methanol - the central intermediate - was found to be noticeable higher when produced by gasification of waste plastics compared to current selling prices, which negatively impacts all pathways that go through methanol as the central intermediate. Life-cycle assessment indicates that the production of pyrolysis naphtha from plastics is a carbon intensive operation; no major advantages were found in terms of greenhouse gas emissions for any of the pathways producing C2 and C3 olefins. The results of this study can serve as the baseline for future comparison to other plastic waste valorization processes.
BIOMASS FUELS,ENERGY PLANNING, POLICY, AND ECONOMY↗
Sustainable H 2 -Rich Syngas Production via Microwave-Assisted vs Conventional Catalysis of Pinewood
Catalytic gasification of biomass is a promising method for producing hydrogen-rich syngas, which is a valuable resource for cleanenergy applications. In this study, microwave-assisted biomass gasification was compared with conventional thermally driven biomass gasification using pinewood as the biomass without the use of external gasifying agents (such as air, steam, and CO 2 ), under non-catalytic and catalytic conditions. The catalysts consisted of either an iron or a nickel catalyst, and the pinewood used as biomass contained 42% oxygen. This comparative analysis explores the differences in reaction chemistry, product yields, and the role of key reactions such as the water gas shift (WGS) reaction, Boudouard reaction, etc. The gas-phase and liquid-phase products were analyzed using online gas chromatography, and the fresh and spent catalysts were analyzed using X-ray diffraction (XRD) techniques. It was found that microwave-assisted gasification offers advantages in terms of enhanced reaction efficiency, catalyst stability, and hydrogen yield. For the microwave-assisted reaction, the gas yield reached 87%, the char yield was 12.1%, and the tar yield was less than 1% (0.793%) at 550 °C. In contrast, thermal-assisted gasification using the same catalyst produced a gas yield of 85.796%, char yield of 11.438%, and higher tar yield of 2.8% at 900 °C. The higher microwave-assisted performance was attributed to faster heating and better control over reaction conditions, higher reaction rates, and more favorable conditions for hydrogen production.
biomass↗
TEA and LCA Assessments of H2 Production from Coal, Coal/Biomass, and Biomass
This presentation was made at the "Gasification Technology Status and Pathways for Net-Zero Carbon Economy Workshop" held on November 30, 2022. The presentation primarily focuses on TEA/LCA results that NETL has developed for coal gasification w/ & w/o CCS as well as net-zero greenhouse gas coal/biomass gasification. Full reporting of these cases is publicly available in the NETL report titled "Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies," April 2022. Additionally, the presentation describes current NETL work in support of the U.S. Department of Energy (DOE) Office of Fossil Energy and Carbon Management (FECM) Gasification Program in the areas of TEA/LCA/Markets analysis of biomass/MSW/waste plastics gasification to achieve cost reductions for net-zero H2 production.
Lewis, Eric↗
Performance Testing of a Moving-Bed Gasifier Using Coal, Biomass, and Waste Plastic Blends to Generate White Hydrogen
The objective of this DOE-funded project by the Electric Power Research Institute, Inc. (EPRI), Hamilton Maurer International (HMI) and Sotacarbo S.p.A. (Sotacarbo), is to qualify coal, biomass, and plastic waste blends based on performance testing of selected pellet recipes in a pilot-scale updraft moving-bed gasifier. The testing will provide relevant data to advance the commercial-scale design of the moving-bed gasifier to be able to successfully use these feedstocks to produce hydrogen. In particular, the effects of the waste plastics on feedstock development (i.e., blending and pelletizing) and the resulting products (i.e., syngas compositions, organic condensate production, and ash characteristics) are a focus. The gasifier is Hamilton Mauer International, Inc. (HMI)’s moving-bed gasifier, which has been proven capable of gasifying nearly all coal ranks. It has also shown the ability in prior testing work to gasify wood chips. However, mixtures of these fuels with plastic wastes have not been prepared and gasified together. The feedstocks will be prepared by California Pellet Mill (CPM) under contract to HMI. The technical tasks and current status for this two-year research project are: Feed Procurement and Preparation: Nine different feedstocks were prepared from varying compositions of PRB coal, corn stover biomass, and car fluff waste plastics. Fuel pellets were produced by California Pellet Mill and shipped to Sotacarbo’s test facility in Italy. Test Plan Development: A test plan was created to define the test runs to be performed. The test plan detailed the different tests that were run, instrumentation used, extractive samples taken, and relevant figures of merit. Gasifier Testing: Tests are currently being performed in the pilot-scale gasifier at Sotacarbo using nine different fuel feedstocks generated from varying mixtures of coal, biomass, and plastic wastes. The testing will provide information on gasification reaction efficiency/performance, yielding relevant data for models used to scale up the gasifier design. This task will also include work to reassemble the gasifier at Sotacarbo and perform a baseline 100% coal run. Data Analysis and Reporting: Review of the data, determination of figures of merit, and interpretation of the results to be reported. The results will be used to specify the range of feedstock blends that can be successfully gasified as well as quantify gasifier outputs based on specific blends. This paper will be summarize the pelletizing procedure that insures the viability of the tri-fuel pellets for the gasification runs that are being performed at Sotacarbo’s 30mm up draft moving bed gasifier. Initial gasification tests have been conducted, and all the lab scale tri-fuel pellet gasification runs will be completed by the fall of 2022. Performance data will enable modeling of a full-scale HMI industrial scale gasifier supporting both CHP and Hydrogen production.
01 COAL, LIGNITE, AND PEAT↗
Microwave-Assisted Reforming of Tar Model Compound Using the Ni/La-CeO2 Catalyst
Gasification of solid feedstocks like coal, biomass and waste plastic produces syngas as a desired product. However, this process also produces an unwanted byproduct known as tar, which is a sticky compound consisting of a mixture of complex aromatic and polyaromatic hydrocarbons. The tar formed during the gasification process lowers the syngas yields and reduces the gasification efficiency by damaging the reactor. Therefore, it is essential to reduce the amount of tar formed during the gasification process. Catalytic reforming of tars is one way to mitigate tars. The goal of this research is to explore the possibility of microwave-assisted catalytic tar conversion to syngas. However, due to the complexity of the tar, toluene has been used as a model tar compound as it is stable and easy to handle. Ni-La/CeO2 was used as a catalyst for this study, which was synthesized by wet impregnation method. Fresh and spent catalysts were analyzed using various techniques to understand the reaction mechanism. The reaction was performed both under microwave (MW) and conventional (CV) reactor for comparison.
catalysis↗
Design Study for Bio-Oil Production from Biomass Using a Dual Fluidized-Bed Reactor
To evaluate the re-design and reconfiguration of a dual-fluidized bed (DFB) gasification system into a recirculating pyrolysis reactor, Computation Fluid Dynamic (CFD) simulations of the system were conducted. The Barracuda Virtual Reactor® computational particle fluid dynamic code was used to perform simulations of the pyrolysis process. Modeling of the chemical reaction kinetics for both gas phase and solid particle phase were included. The recirculating pyrolysis reactor shown in Fig. 1a is based on a bubbling-bed biomass pyrolyzer and a riser combustor to convert the remaining char. The operational differences in the re-configuration of the DFB gasification system into a recirculating pyrolysis system for the production of bio-oil are (1) replacement of a low-surface area inert bed material with a high-surface-area bed material that has acidic properties to provide catalytic activity for the production of bio-oil with reduced oxygen content, (2) lower temperature and residence time for bio-oil production from pyrolysis, (3) replacement of the fluidization gas in the bubbling bed pyrolyzer from steam to nitrogen, and (4) the reduction of pyrolyzer freeboard volume. The bed material used for catalytic pyrolysis is Sasol 300 (300-micron dia., bulk density 0.94 kg/l, and surface area 130 m2/g) and is a theta-alumina with mild acidity. This is in comparison with previous standard bed material Carbo HSP (430-micron dia., bulk density 2.01 kg/l, and surface area 0.03 m2/g) used for gasification. For bio-oil production, pyrolysis in the bubbling bed requires temperatures in the range of 550 C in comparison with gasification temperatures near 850 C. To attain this lower temperature requires management of the energy mass balances, with control of the bed material recirculation rate between bubbling bed pyrolyzer and riser combustor, the introduction of a nitrogen purge in the pyrolyzer, and adjusting the pressure balance between the two vessels. To extract bio-oil from the pyrolysis reactor with a snorkel, two different freeboard configurations were evaluated. In Fig. 1 b the existing high freeboard configuration is shown and in Fig. 1 c the reduced freeboard design is presented. The introduction of a nitrogen purge for the high free board configuration provided the highest bio-oil production from the CFD simulations. To decrease the bed-material circulation rate, primary and secondary air on the combustor side were reduced, and the pressure on the combustor was slightly increased. A portion of the biomass and bio-oil was observed to be transported to the combustor, leading to a smaller pyrolysis yield. The control of the pyrolyzer temperature is performed by controlling the circulation rate. Good fluidization of the bubbling bed and cascade PID control are required to keep the temperature from oscillating due to large time delay experienced when changing primary and secondary air. (a) (b) (c) Figure 1. (a) Dual Fluidized Bed pyrolysis system configuration, (b) mole fraction of nonpolar biooil in high freeboard configuration, and (c) mole fraction of nonpolar bio-oil in low freeboard configuration with nitrogen purge introduced in both configurations.
BASIC BIOLOGICAL SCIENCES,BIOMASS FUELS↗
Wabash Hydrogen Negative Emissions Technology Demonstration
The objectives of the Wabash Hydrogen Negative Emissions Technology Demonstration Project (Wabash Project) are to develop and design all aspects of the scope, cost, characteristics and investment case of a world class flexible gasification, net negative carbon, hydrogen co-products power plant. The outcome of this undertaking is a complete set of deliverables that has been produced by a preeminent team of engineers, constructors, operators, and developers, building upon previous technology, utilizing cutting edge technology, and thoroughly defining all aspects of this fully integrated 21st Century Powerplant. The Wabash Project encapsulates several cross-cutting initiatives within the US Department of Energy, such as 100% hydrogen powered combustion turbine, geological carbon sequestration, coal with biomass gasification and hydrogen energy storage. The flexible gasifier at the Wabash Valley Resources plant is a slurry-fed, entrained flow, high-temperature, oxygen-blown gasifier that has been proven commercially to operate successfully on various coals and petroleum coke (petcoke). The ability to be fuel flexible and feed various biomass (woody biomass and agriculture residue) and petroleum waste (plastics) was evaluated during BP 1 (BP1). This involved the preparation and testing of feedstocks into slurries to determine what fuels can be fed to the gasifier. By utilizing a flexible oxygen-blown gasifier, the ability to address operational issues common to lower temperature biomass gasification, such as the handling of tars, can be mitigated. The overall goal is to achieve a design capable of carbon-negative emissions while leveraging the substantial investments made and operating experience already gained at the Wabash site.
01 COAL, LIGNITE, AND PEAT↗
A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal
We report this research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO 2 -char gasification by as high as 75.00%. In the 2nd stage, the H 2 /CO ratio of ideal syngas is ~2:1 with near-0 CH 4 generation and the CH4 production can be reduced as high as 61.29% for the CO 2 –H 2 O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion.
01 COAL, LIGNITE, AND PEAT↗
Radically Engineered Modular Air Separation System with Tailored Oxygen Sorbents
The commercial energy sector relies heavily on fossil fuel conversion, and in the process releases a significant amount of CO 2 . A promising technology to utilize fossil fuels with relatively affordable CO 2 capture is gasification. However, it requires a pure oxygen stream. The current state of the art method to produce oxygen is cryogenic air separation, which supercools air to a liquid, and then using distillation columns to separate the components. While this method has been thoroughly studied, it only has a 25% efficiency from a second law standpoint and therefore requires a significant amount of energy (and associated emissions) for oxygen production. This, then, lowers the incentive for carbon capture within a plant, so alternative methods need to be investigated. One potential method, chemical looping air separation (CLAS), is a promising method to replace state of the art oxygen generation technologies. CLAS utilizes a cyclic redox scheme with an oxygen sorbent to create pure oxygen streams. This approach typically utilizes a dual reactor scheme where the oxygen deficient sorbent enters the first reactor and is subjected to high oxygen partial pressures to re-oxidize the sorbent. Then the sorbent is sent to the reducing reactor, where it is subjected to low oxygen partial pressure (steam or vacuum) to releases oxygen. The overarching objective of this project was to discover the principles for rational design and optimization of oxygen sorbents and process design to ensure the process is a viable replacement for cryogenic air separation, especially in the context of modular gasification systems. This was done through development, characterization, testing, and analyses of (a) high temperature mixed composite oxides; (b) low temperature doped perovskite oxides (A1 x A2 1-x B1 y B2 1-y O 3 ); (c) scale up synthesis and testing of the optimized sorbent particles; (d) process design and analyses of the CLAS system in the context of modular gasification applications.
01 COAL, LIGNITE, AND PEAT↗
Chapter 11: Biochar Production
In production of biochar, thermochemical processes that can be used to treat biomass include pyrolysis, gasification, hydrothermal processing, and combustion. Each of these processes is defined by specific operating conditions (e.g., temperature, presence of oxygen) and feedstock requirements for optimal conversion to the product of primary interest. Each process results in varying fractions of gaseous, liquid, and solid products. Though other publications have emphasized the gaseous bio-energy products of such processes (e.g., bio-oil, synthesis gas or "syngas") with biochar as a co-product, in this discussion, we focus primarily on biochar as the In production of biochar, thermochemical processes that can be used to treat biomass include pyrolysis, gasification, hydrothermal processing, and combustion. Each of these processes is defined by specific operating conditions (e.g., temperature, presence of oxygen) and feedstock requirements for optimal conversion to the product of primary interest. Each process results in varying fractions of gaseous, liquid, and solid products. Though other publications have emphasized the gaseous bio-energy products of such processes (e.g., bio-oil, synthesis gas or "syngas") with biochar as a co-product, in this discussion, we focus primarily on biochar as the main product, with heat and electrical energy as co-products of secondary interest. The reasons for this are as follows: when producing biochar, heat is the simplest form of energy to capture and utilize, electrical energy can be generated from heat energy with a wide range of available technologies small and large; rather than immediately combusting the gases released from biomass, there is potential to refine the gases into bio-oil and syngas. However, much larger investments of capital are needed to build facilities for which gaseous fuel production is the primary goal, as compared to those focused on biochar production with heat and electrical energy co-products. While the economic viability of biochar production will be improved by production of high-value co-products (e.g., wood acids for use in pesticides), the simplest production scheme is one in which biochar and heat are the primary products. Here we aim to provide a broader overview of thermochemical processes and technologies most relevant to biochar production in its current state of commercialization. All biochar is a result of pyrolysis (the reaction) but not all biochar is made with a dedicated pyrolysis reactor (the technology type). Further, all biochar is the result of a lack of complete combustion (the reaction), even biochar produced in a combustion or gasification reactor (the technology type). This is an important distinction to acknowledge in the following sections in which we discuss both thermochemical conversion reactions and technology types.
biochar↗
Modeling Framework for the Assessment of a Sustainable Hydrogen Production and Supply Chain Network in California
The cost-effective and sustainable deployment of hydrogen supply and demand networks, especially in large economic regions like California, can be challenging considering the spatial-temporal availability and variability of the different actors across the network such as production processes, distribution modes, and end-users. In this presentation, we will provide an overview and demonstration of a modeling framework used to assess the environmental, economic, and human health impacts of plausible hydrogen production and supply chain networks in California. Scenarios focus on green hydrogen production pathways using water electrolysis and biomass gasification. End-use applications included in the model are transit, medium and heavy-duty trucking, port authorities, and power and aviation companies that currently consume natural gas, diesel, and aviation fuel for their day-to-day operation. Representative locations for hydrogen production and end-use are based on recent projections of the hydrogen economy in California. All mass and energy flows, as well as estimated emissions, are based on H2A process model designs and projections of technology performance, literature review, and LBNL process, economic and life cycle modeling, and not on company data for the sake of this presentation. Human health impacts are included following methodologies developed for the University of California Irvine HyDeal project. Life cycle phases associated with hydrogen production include feedstock preparation (water and biomass), energy production and consumption (renewable, grid, and combination of renewable and grid electricity), maintenance (chemical utilization in electrolysis and natural gas combustion in gasification), carbon sequestration, hydrogen storage (compression and liquefaction), and distribution (truck and pipeline). We apply the framework utilizing California specific emission factors, financial data, and human health damages and explore the impact of network characteristics on results. Example variations include: the inclusion of policy incentives or not, different representations of the electricity grid and source, electrolysis versus gasification versus combinations of both for production, liquefaction versus compression based on producer capacity cutoffs, transportation truck versus pipeline based on existing infrastructure, and ultimate end use. Comparison of these different scenarios can help inform future projects by demonstrating the trade-offs among environmental, economic, and human health impacts. This model, automated in R, is a starting platform upon which new analysis, modeling capabilities, locations, and emission factors can be rapidly tested and integrated.
Zaki, Mohammed Tamim↗
Small-Scale Engineered High Flexibility Gasifier
This project advances a small-scale gasification unit as the first step in syngas-based hydrogen, chemicals, and synthetic fuels production. This unit is associated with an enhanced flexibility to different carbonaceous feedstocks including different types of coals, biomass, and plastics. The purpose of the project was to demonstrate feasibility and efficiency of coal pyrolysis in an auger reactor (pyrolyzer); supplemental methane and pyrolysis gas conversion into syngas in a proprietary non-catalytic converter; combined performance of pyrolyzer and non-catalytic converter to convert coal into syngas The proposed technology is based on an application of an intermediate speed pyrolysis at the temperature range 400-600°C as the first stage of biomass processing. At an industrial scale, an incorporation of coal pyrolysis into a feeding machine – auger-reactor allows to decrease its capital cost. At a pilot scale, it permits to employ electricity to build a compact device for testing of downstream equipment. The auger-reactor (pyrolyzer) generates pyrolysis gas and char practically from any carbonaceous feedstocks but their compositions and quantities are determined by their types. Pyrolysis gas is converted into syngas (mix of H 2 and CO) in a novel, proprietary hydrogen flame assisted non-catalytic converter which employs O 2 instead of air as an oxidizer. This reactor (converter) allows an easy adjustment to different pyrolysis gas compositions and tolerates a presence of sulfur and nitrogen contaminants. Our technology assumes carbonaceous feedstocks gasification with oxygen to allow the products H 2 , CO or CO 2 to be not diluted in N 2 and ready for the following synthesis of chemicals and fuels. Due to the same reason, it permits a more efficient CO 2 capture for its transport and storage. An implementation of our small-scale gasification process may overcome economic constrains by a flexible acceptance of coal, biomass, and plastics as well as their unsorted mixtures to make syngas for the following production of pure hydrogen, chemical and/or synthetic fuels.
42 ENGINEERING↗
Pilot Testing of a Highly Efficient Pre-combustion Sorbent-based Carbon Capture System
TDA developed and demonstrated a highly efficient pre-combustion carbon capture system. The overall objective of this work was to develop a new sorbent-based pre-combustion carbon capture technology for Integrated Gasification Combined Cycle (IGCC) power plants. In this project our goal was to demonstrate the techno-economic viability of the new technology by 1) demonstrating it in large-scale slipstream tests, and 2) carrying out a high fidelity engineering and cost analysis. TDA’s process used an advanced physical adsorbent that selectively removes CO 2 from coal-derived synthesis gas above the dew point of the gas at temperatures as high as 300°C. The sorbent consists of a mesoporous carbon whose surface was grafted with functional groups that remove CO 2 via a well-known acid-base interaction. As documented in bench-scale experiments and field tests with actual coal gas, the sorbent achieved a very high capacity for CO 2 at temperatures as high as 300°C. The sorbent bound CO 2 more strongly than common physical adsorbents, providing the chemical potential needed for the high temperature operation. However, because CO 2 does not form a true covalent bond with the surface sites (as is the case with chemical absorbents), the sorbent regeneration could be carried out with only a very small energy input. The heat input to regenerate our sorbent was only 4.9 kcal per mol of CO 2 , which is much lower than that for chemical absorbents (e.g., 29.9 kcal/mol CO 2 for sodium carbonate) and was similar to the requirements of physical solvents (e.g., 4 kcal/mol CO 2 for Selexol TM ). Because the sorbent operates above the dew point of the synthesis gas (unlike the Selexol TM process), a higher power cycle efficiency can be achieved. With previous DOE/NETL funding (Contract No. DE-FE-0000469), we demonstrated the techno-economic viability of the technology in bench-scale tests and slipstream demonstrations at the National Carbon Capture Center (NCCC), Wilsonville, Alabama and Wabash River IGCC plant in Terra Haute, Indiana. We demonstrated a stable working CO 2 capacity for over 11,650 cycles with simulated synthesis gas. We also evaluated its performance with actual synthesis gas in two test campaigns at the Wabash River IGCC Plant, Terre Haute, IN and the National Carbon Capture Center (NCCC), Wilsonville, AL. The slipstream tests clearly showed that the actual coal gas constituents and potential contaminants (e.g. trace metals, halides, tars) had no effect on the sorbent’s ability to remove CO 2 (the same sorbent beds were used in both field tests with no sign of deactivation for 2,000 cycles with over 26,750 SCF of gas treated). As expected, due to the high temperature CO 2 removal capability and low energy needed to regenerate the sorbent, the power cycle efficiency with our process was greater than 34% on a higher heating value (HHV) basis; in comparison, the same IGCC plant equipped with the Selexol TM solvent for carbon capture can only achieve 31.4% HHV efficiency. The capital cost for an IGCC system with TDA’s process is estimated as $2,417/kW e , which is 12% lower than that of the IGCC/ Selexol TM process. The levelized cost for electricity including the transport, storage and monitoring (TS&M) cost for CO 2 was calculated as $\$ $92.9/MWh (lowest reported to our knowledge), which is much better than the $105.2/MWh estimated for the IGCC/ Selexol TM process. In this project (DE-FE0013105), TDA Research, in collaboration with our partners Gas Technology Institute (GTI), Illinois Clean Coal Institute (ICCI), University of California, Irvine (UCI), University of Alberta (UOA), Siemens, NCCC and Sinopec advanced the technical maturity of the technology; scaling it up by a factor of 100. We optimized the reactor design using computational fluid dynamics (CFD); using adsorption modeling we improved the pressure swing adsorption (PSA) cycle sequence. We carried out two field test campaigns with a fully-equipped 0.1 MW e prototype unit (for a total of 844 hours) using actual synthesis gas to prove the viability of the new technology. A successful 30 day (707 hrs) evaluation was completed at NCCC under air blown gasification conditions. We demonstrated 97.3% carbon capture at 1,500 SLPM, 93% carbon capture at 1,800 SLPM, and 90% carbon capture at 2,100 SLPM in the NCCC tests. We also demonstrated the system for 137 hours at a Sinopec petrochemical plant under oxygen blown gasification, demonstrating 86% carbon capture at 2,660 SLPM. In collaboration with University of California, Irvine (UCI), we completed a techno-economic analysis (TEA) for TDA’s warm gas cleanup technology integrated to IGCC power plant. The net plant efficiencies (on a coal HHV basis) for the warm gas cleanup cases were estimated to be 34.0% for E-GasTM gasifier, 34.4% for GE gasifier, 33.4 for the Shell gasifier and 34.2 for the TRIG TM gasifier (Cases 2, 4, 6 and 8 in this study) with a catalytic combustor for CO 2 purification, which are significantly higher than those for the Cold Gas Case, or an increase of as much as 12% in the heat rate for Case 2, 6% for Case 4, 9% for Case 6, and 9% for Case 8. The 1st year cost of electricity with the transport, storage and monitoring (TS&M) costs for the CO 2 included was $\$ $129.2/MWh for the E-GasTM gasifier Warm Gas Cleanup Case, $\$ $131.9/MWh for the GE gasifier Warm Gas Cleanup Case, $\$ $146.8/MWh for the Shell Gasifier Warm Gas Cleanup Case, and $\$ $129.9/MWh for the TRIG TM gasifier Warm Gas Cleanup Case. For comparison, the costs for the baseline Cold Gas CO 2 removal with Selexol for the different gasifiers were: $\$ $146.6/MWh for the E-Gas TM gasifier, $\$ $142.2/MWh for the GE gasifier, $\$ $159.0/MWh for the Shell gasifier and $\$ $144.3/MWh for the TRIG TM gasifier. In summary, the costs for our system were 7 to 12% lower than the corresponding Cold Gas Cleanup cases. The results of this techno-economic analysis suggested that TDA’s high temperature PSA-based Warm Gas Clean-up Technology can make a substantial improvement in the IGCC plant thermal performance for achieving near zero CO 2 emissions for E-Gas TM , GE, Shell and TRIG TM gasifier based IGCC power plants. The capital expenses were estimated to be lower than that of Selexol’s™. Taken together, the higher net plant efficiency and lower capital and operating costs resulted in substantial reduction in the cost of carbon capture for the IGCC plant equipped with TDA’s high temperature PSA-based carbon capture system. Finally, in collaboration with Gas Technology Institute (GTI) we completed the environmental health and safety assessment for TDA’s warm gas carbon capture technology.
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