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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

High Energy Systems for Transforming CO 2 to Valuable Products (Final Report)

The objective of this project is to develop the Direct E-Beam Synthesis (DEBS) process that uses high-energy electron beams (E-Beam) to break chemical bonds. This allows the production of valuable chemicals, such as acetic acid, methanol, and carbon monoxide, at relatively low severity (pressure near one atmosphere and temperatures <150°C) from near-pure CO 2 captured from a pulverized coal-fired power plant and methane, imported as natural gas. Creating such valuable products will offset the cost of carbon capture and storage. Through this project, we have designed, constructed, and operated an E-Beam reactor to examine the feasibility of performing dry reforming reaction without a catalyst using only DEBS. We have verified the production of syngas with 1:1 H2:CO ratio and calculated that the energy cost for conversion is about 5.2 eV/molecule of product for dry reforming reaction which is similar to the energy cost for conversion using conventional thermochemical conversion but under significantly milder conditions (room temperature and atmospheric pressure). We have performed a technoeconomic analysis (TEA) to estimate the total capital requirement and the cost of production for a 99.4 MMSCFD syngas production plant via non-catalytic Direct E-Beam Synthesis (DEBS) technology utilizing a high-energy electron beam (E-Beam) accelerator. No assumption is made for syngas utilization downstream, and the incoming reactants are pure CO 2 from carbon capture (assumed to be at zero cost) and natural gas. The Total As-Spent Cost (TASC) was calculated to be $\$242.5$ million, resulting in a levelized cost of syngas (LCOS) of $\$175.84$/tonne (metric) at a natural gas price of $\$6.24$/MMBTU1. The cost of syngas is primarily determined by the price of natural gas. If the cost of the CO 2 feedstock is assumed to be non-zero, then the price of the CO 2 feed also heavily influences the levelized cost of syngas. The potential impact on the cost of electricity from syngas revenue is significant. Following DOE NETL’s guidance, a lifecycle analysis (LCA) was conducted to compare the cradle-to-gate life cycle emissions of GTI Energy’s novel Direct E-Beam Synthesis (DEBS) process that produces syngas via the reaction of methane and carbon dioxide to the emissions of a state-of-the-art Steam Methane Reforming (SMR) process that also produces syngas via the reaction of methane and steam. The DEBS process results in less GHG emissions than SMR (with CO product as the basis of comparison). openLCA was used for the LCA and the results show that the total global warming potential (GWP) of DEBS is 0.981 kg CO 2 e per kg CO product, while the SMR process has a global warming potential of 2.573 kg CO 2 e per kg CO product. The ratio of the GWP of the proposed product system to the comparison product system is 0.381. This percent change is 61.9% lower GWP than SMR.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2012

Long-Term Demonstration of Hydrogen Production from Coal at Elevated Temperatures: Year 6 - Activity 1.12 - Development of a National Center for Hydrogen Technology

The Energy & Environmental Research Center (EERC) has continued the work of the National Center for Hydrogen Technology® (NCHT®) Program Year 6 Task 1.12 project to expose hydrogen separation membranes to coal-derived syngas. In this follow-on project, the EERC has exposed two membranes to coal-derived syngas produced in the pilot-scale transport reactor development unit (TRDU). Western Research Institute (WRI), with funding from the State of Wyoming Clean Coal Technology Program and the North Dakota Industrial Commission, contracted with the EERC to conduct testing of WRI’s coal-upgrading/gasification technology for subbituminous and lignite coals in the EERC’s TRDU. This gasifier fires nominally 200–500 lb/hour of fuel and is the pilot-scale version of the full-scale gasifier currently being constructed in Kemper County, Mississippi. A slipstream of the syngas was used to demonstrate warm-gas cleanup and hydrogen separation using membrane technology. Two membranes were exposed to coal-derived syngas, and the impact of coal-derived impurities was evaluated. This report summarizes the performance of WRI’s patent-pending coal-upgrading/ gasification technology in the EERC’s TRDU and presents the results of the warm-gas cleanup and hydrogen separation tests. Overall, the WRI coal-upgrading/gasification technology was shown to produce a syngas significantly lower in CO 2 content and significantly higher in CO content than syngas produced from the raw fuels. Warm-gas cleanup technologies were shown to be capable of reducing sulfur in the syngas to 1 ppm. Each of the membranes tested was able to produce at least 2 lb/day of hydrogen from coal-derived syngas.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Catalytic Production of Ethanol from Biomass-Derived Synthesis Gas

Heterogeneous catalysts have been developed for the conversion of biomass-derived synthetic gas (syngas) to ethanol. The objectives of this project were to develop a clean synthesis gas from biomass and develop robust catalysts with high selectivity and lifetime for C 2 oxygenate production from biomass-derived syngas and surrogate syngas. During the timeframe for this project, we have made research progress on the four tasks: (1) Produce clean bio-oil generated from biomass, such as corn stover or switchgrass, by using fast pyrolysis system, (2) Produce clean, high pressure synthetic gas (syngas: carbon monoxide, CO, and hydrogen, H 2 ) from bio-oil generated from biomass by gasification, (3) Develop and characterize mesoporous mixed oxide-supported metal catalysts for the selective production of ethanol and other alcohols, such as butanol, from synthesis gas, and (4) Design and build a laboratory scale synthesis gas to ethanol reactor system evaluation of the process. In this final report, detailed explanations of the research challenges associated with this project are given. Progress of the syngas production from various biomass feedstocks and catalyst synthesis for upgrading the syngas to C 2 -oxygenates is included. Reaction properties of the catalyst systems under different reaction conditions and different reactor set-ups are also presented and discussed. Specifically, the development and application of mesoporous silica and mesoporous carbon supports with rhodium nanoparticle catalysts and rhodium nanoparticle with manganese catalysts are described along with the significant material characterizations we completed. In addition to the synthesis and characterization, we described the activity and selectivity of catalysts in our micro-tubular reactor (small scale) and fixed bed reactor (larger scale). After years of hard work, we are proud of the work done on this project, and do believe that this work will provide a solid foundation for the future production of syngas from biomass and the development of heterogeneous catalysts for the syngas to C 2 -oxygenate process and for the commercialization of this process. Potential future directions for this research are also discussed within the report.

09 BIOMASS FUELS↗
DOE OSTI2017

Uncertainty Quantification Analysis of Both Experimental and CFD Simulation Data of a Bench-scale Fluidized Bed Gasifier

Adequate assessment of the uncertainties in modeling and simulation is becoming an integral part of the simulation based engineering design. The goal of this study is to demonstrate the application of non-intrusive Bayesian uncertainty quantification (UQ) methodology in multiphase (gas-solid) flows with experimental and simulation data, as part of our research efforts to determine the most suited approach for UQ of a bench scale fluidized bed gasifier. UQ analysis was first performed on the available experimental data. Global sensitivity analysis performed as part of the UQ analysis shows that among the three operating factors, steam to oxygen ratio has the most influence on syngas composition in the bench-scale gasifier experiments. An analysis for forward propagation of uncertainties was performed and results show that an increase in steam to oxygen ratio leads to an increase in H2 mole fraction and a decrease in CO mole fraction. These findings are in agreement with the ANOVA analysis performed in the reference experimental study. Another contribution in addition to the UQ analysis is the optimization-based approach to guide to identify next best set of additional experimental samples, should the possibility arise for additional experiments. Hence, the surrogate models constructed as part of the UQ analysis is employed to improve the information gain and make incremental recommendation, should the possibility to add more experiments arise. In the second step, series of simulations were carried out with the open-source computational fluid dynamics software MFiX to reproduce the experimental conditions, where three operating factors, i.e., coal flow rate, coal particle diameter, and steam-to-oxygen ratio, were systematically varied to understand their effect on the syngas composition. Bayesian UQ analysis was performed on the numerical results. As part of Bayesian UQ analysis, a global sensitivity analysis was performed based on the simulation results, which shows that the predicted syngas composition is strongly affected not only by the steam-to-oxygen ratio (which was observed in experiments as well) but also by variation in the coal flow rate and particle diameter (which was not observed in experiments). The carbon monoxide mole fraction is underpredicted at lower steam-to-oxygen ratios and overpredicted at higher steam-to-oxygen ratios. The opposite trend is observed for the carbon dioxide mole fraction. These discrepancies are attributed to either excessive segregation of the phases that leads to the fuel-rich or -lean regions or alternatively the selection of reaction models, where different reaction models and kinetics can lead to different syngas compositions throughout the gasifier. To improve quality of numerical models used, the effect that uncertainties in reaction models for gasification, char oxidation, carbon monoxide oxidation, and water gas shift will have on the syngas composition at different grid resolution, along with bed temperature were investigated. The global sensitivity analysis showed that among various reaction models employed for water gas shift, gasification, char oxidation, the choice of reaction model for water gas shift has the greatest influence on syngas composition, with gasification reaction model being second. Syngas composition also shows a small sensitivity to temperature of the bed. The hydrodynamic behavior of the bed did not change beyond grid spacing of 18 times the particle diameter. However, the syngas concentration continued to be affected by the grid resolution as low as 9 times the particle diameter. This is due to a better resolution of the phasic interface between the gases and solid that leads to stronger heterogeneous reactions. This report is a compilation of three manuscripts published in peer-reviewed journals for the series of studies mentioned above.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Bench-Scale Testing of a High Efficiency, Ultra-Compact Process for Pre-Combustion CO 2 Capture (Final Report)

The overarching objective of this bench-scale study is to field-validate the technical feasibility of a membrane- and adsorption-enhanced water gas shift (WGS) reaction process that employs a carbon molecular sieve (CMS) membrane reactor (MR) followed by an adsorption reactor (AR) for pre-combustion CO 2 capture while demonstrating progress towards achievement of the overall performance goals of CO 2 capture with 95% CO 2 purity at a cost of electricity (COE) of 30% less than the baseline capture approaches. The main goal of this bench-scale project is to advance the proposed MR-AR transformative CO 2 capture technology to a sufficient maturity level so that our present industrial partners (M&PT and Worley) can potentially adapt the technology for further small pilot-scale testing. The project began at TRL 4, as the system prototype had already been validated in the laboratory on simulated syngas (as part of project DE-FE0026423). The project ended at TRL 5, via scaling-up of the prototype system and testing it on actual syngas at a host site (CAER at the University of Kentucky (UKy)). The project was carried-out in two different phases: In Phase I (during BP1 of the project), the team designed, constructed, and assembled the bench-scale experimental MR-AR system, prepared the membranes, adsorbents, and catalysts, tested the bench-scale unit with simulated syngas to validate functionality, and prepared a preliminary TEA of the technology. In Phase II (during BP2 of the project), the team installed the unit at the test site at the UKy site and completed all utility connections and hookups, field-tested the novel MR-AR process in the bench-scale system using real syngas, collected and analyzed experimental data, and completed a detailed TEA of the technology. A key aim of the project was to identify and address the technical and process risks and to generate information to advance the technology to the next stage of development. All project milestones and success criteria were met. Specifically, the team: (i) designed, constructed and assembled a bench scale system that handled 1 – 5 scfm syngas and tested its functionality with simulated syngas; (ii) prepared high performance CMS membrane tubes (ID: 3.5 mm, OD: 5.7 mm, 30” long) that meet the target H 2 permeance ( > 1 m 3 /(m 2 .hr.bar) or (> 370.3 GPU)) and a target H 2 /CO selectivity >80 at the relevant temperature (up to 300oC) and pressure conditions (up to 25 bar) with a <10% decline in performance over each 250 hr. testing period (iii) procured commercial sour-shift catalyst in sufficient quantity and prepared up to 10 kg of pelletized adsorbent for use at relevant conditions (250oC 2.5wt.% and target sorbent attrition rate < 0.2; (iv) installed the bench-scale unit at the test site (UKy) and tested the MR-AR technology using real syngas for over 250 hr. for both static and flow experiments; (v) updated the TEA analysis based on bench-scale data and met CO 2 capture goals of 95% CO 2 purity at a cost of electricity 30% less than baseline capture approaches. The CMS membranes, HTC adsorbents and catalysts employed all exhibited very robust and stable performance during the long-term run (over a >250 hr live syngas run). Furthermore, the proposed MR-AR IGCC system achieved a LCOE with a N 2 sale price of $\$$ 30/ton, with N 2 compression (no N 2 compression) of 101.2 $\$$/MWh (95.3 $\$$/MWh), which represents a 29.8% (33.9%) LCOE reduction in the baseline IGCC with carbon capture of 144.2 $\$$/MWh. The proposed MR-AR IGCC delivers a CO 2 capture cost of 44.8 $\$$/tonne (39.9 $\$$/tonne) vs 98.1 $\$$/tonne of the baseline capture case and a net power production of 586 MWe (623 MWe) vs 556 MWe of the baseline capture case.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

Preparation and Testing of Corrosion-and Spallation-Resistant Coatings

This Energy & Environmental Research Center (EERC) project is designed to determine if plating APMT®, a specific highly oxidation-resistant oxide dispersion-strengthened FeCrAl alloy made by Kanthal, onto nickel-based superalloy turbine parts is a viable method for substantially improving the lifetimes and maximum use temperatures of the parts. The method for joining the APMT plate to the superalloys is called evaporative metal bonding and involves placing a thin foil of zinc (Zn) between the plate and the superalloy, clamping them together, and heating in an atmosphere-controlled furnace. Upon heating, the Zn melts and dissolves the oxide skins of the alloys at the bond line, allowing the two alloys to diffuse into each other. The Zn then diffuses through the alloys and evaporates from their surfaces. Laboratory testing to determine the diffusion rate of Zn through the alloys has been completed. We have found that we were not able to create joints when temperatures much lower than the original temperature of 1214°C are used. Therefore, we limited our diffusion rate measurements to the two hold temperatures used in the procedure: 700° and 1214°C. The diffusivity of zinc in both APMT and CM247LC is quite similar at 700°C. Diffusivity in the APMT appears to be slightly higher, but the midline composition after 30 minutes at this temperature is quite similar. At 1214°C, the situation is very different. The calculated diffusivity of zinc in APMT is approximately 15 times higher than in CM247LC or Rene® 80 (~120 vs. ~8 μm²/min) at that temperature. In addition to the diffusion work, the coefficients of thermal expansions were determined for each of the alloys as a function of temperature. This information has been entered into a finite element model using ANSYS so that appropriate force-applying structures can be designed for use in joining structures composed of APMT and the nickel alloys. Gasifier sampling activities continue to determine what types of trace contaminants may occur in cleaned syngas that could lead to corrosion or deposition in turbines firing coal syngas. The EERC has several pilot-scale gasifiers that are continually used in a variety of test configurations as determined by the needs of the projects that are funding the tests. We are sampling both noncombusted and combusted syngas produced during some of the pilot-scale gasifier tests. After modifying our sampling procedures to minimize contamination from the oxidizer, we obtained very good filter samples from both syngas and from the combustion products of the syngas blended with natural gas. Scanning electron microscopy analyses showed that the particles captured on the filter from the syngas were typically 0.2 to 0.5 μm in diameter, whereas those captured from the combusted syngas were slightly larger and more spherical. However, the particles were so small that we could not obtain good spectra from them either at the EERC or JEOL America, the maker of the EERC electron microscope systems. Therefore, the EERC applied for and received time on electron microscopes using different signal analyzers at the Oak Ridge National Laboratory (ORNL) ShaRE User Facility, which is sponsored by the U.S. Department of Energy Scientific User Facilities Division of the Office of Basic Energy Sciences. At ORNL, both x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy were performed on the samples because these are surface analyses that analyze electrons emitted from within a few nanometers of the surfaces of the particles and filters. The XPS data show that the particles do not contain any metals and, in fact, have an atomic composition almost identical to that of the polycarbonate filter. We currently believe that this indicates that the particles are primarily soot-based and not formed from volatilization of metals in the fluid-bed gasifier. The data indicate that the soot-based particles are not well burned in the thermal oxidizer, although they are significantly oxidized, nitrided, and sulfidized in the combustor. Ion etching to remove the surfaces of the particles indicates that the oxidation, nitridation, and sulfidation of the particles are primarily surface phenomena.

Electric↗
DOE OSTI2019

High-Octane Gasoline from Biomass: Experimental, Economic, and Environmental Assessment

Five economically-advantaged biomass feedstocks identified in the United States Department of Energy's 2016 Billion Ton Study were gasified and the syngas was reformed at the bench scale to study the feedstock price-performance relationship. The distribution of reformed syngas compositions, heating values, and yields were similar across the different feedstocks and blends thereof, which ranged from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. The experimental gasification data informed a techno-economic analysis of specific feedstock costs for producing high-octane gasoline, and the results showed that miscanthus and forest residues were the most cost-effective. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied. from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. The experimental gasification data informed a techno-economic analysis of specific feedstock costs for producing high-octane gasoline, and the results showed that miscanthus and forest residues were the most cost-effective. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied.

09 BIOMASS FUELS↗
DOE OSTI2019

Gasification of coal, Chenopodium Album biomass, and co-gasification of a coal-biomass mixture by thermogravimetric-gas analysis

Gasification studies were performed on sub-bituminous coal of the province Centro in Boyacá state of Colombia, vegetable biomass Chenopodium album (cenizo) and co-gasification of coal-biomass mixtures agglomerated with paraffin in a thermogravimetric analyzer. Biomass synergistically promoted thermochemical transformation of the coal was observed. Experimental results were compared to equilibrium composition simulations. Ash fusibility tests of the coal-biomass mixture were carried out, which allowed to clarify its behavior, such as dry or fluid ash according to own chemical composition, during the gasification process. The experimental tests allowed determining the differences in thermal decomposition, between coal, cenizo and coal-biomass blend, which are attributable to the physicochemical properties of each one solid fuel. During the tests, gas chromatography analyses were performed to establish the compositions of the syngas. The syngas obtained from biomass had the highest concentration of CO and the lowest H 2 ; the coal and the coal-biomass mixture were slightly minor respectively. Concentrations of CH 4 , CO 2 and C 2 H 4 were similar between coal and biomass. This result is consistent with the higher calorific value of the coal syngas. The production of syngas from the coal-biomass mixture had the lowest contents of H 2 and CO due to synergistic phenomena that occur with the fuel mixture. The co-gasification of the mixture gave the highest syngas production, carbon conversion, and thermal efficiency. These results indicate the viability of co-gasification of coal- Chenopodium album agglomerated mixtures. In gasification of non-agglomerated mixtures of coal-cenizo, the biomass can be burned directly without producing syngas.

09 BIOMASS FUELS↗
DOE OSTI2018

Reforming sewage sludge pyrolysis volatile with Fe-embedded char: Minimization of liquid product yield

Highlights: • Fe{sub 2}(SO{sub 4}){sub 3} is added in sewage sludge to produce pyrolysis char (SSC) embedded with Fe. • Fe-embedded SSC is utilized to reform the same source volatile to produce high quality syngas and avoid liquid products. • More gas is produced with raised H{sub 2} content as Fe concentration elevated in the Fe-embedded SSC. • Total liquid product and its oily fraction decreased greatly after reformed with Fe-embedded SSC. - Abstract: Obtaining high quality syngas from sewage sludge (SS) means transferring a low-grade SS into a high-grade fuel or raw materials for chemical products. In this study, Fe is added to SS in form of Fe{sub 2}(SO{sub 4}){sub 3} to produce an effective and self-sufficient catalyst in order to obtain more syngas and minimize liquid products from SS pyrolysis. The Fe-embedded sewage sludge chars (SSCs) were used as catalysts for volatile reforming at 600 °C. It has been found that the gas yield increases from 15.9 to 35.8 wt% of the SS and that of liquids decreases from 31.9 to 10.2 wt% after volatile reforming with Fe-embedded SSC when Fe was added equal to 7 % in the dried SS. In addition, the content of nitrogen-containing compounds in the oily products decreased. After reforming with Fe-embedded SSC, the molar fractions of syngas combustible components, including H{sub 2}, CH{sub 4} and CO, increase, and the higher heating value of the syngas increased to 17.0 MJ/Nm{sup 3} from the original 12.5 MJ/Nm{sup 3} obtained from SS pyrolysis at 550 °C. Moreover, the volatile reforming seems to reduce the level of some important syngas pollutants, like H{sub 2}S, HCl and HCN, even though it was also observed an increase of the contents of SO{sub 2}, NH{sub 3}, NO{sub 2,} HCNO and N{sub 2}O.

09 BIOMASS FUELS↗
DOE OSTI2018

Indirect Liquefaction of Coal-Biomass Mixture for Production of Jet Fuel with High Productivity and Selectivity

Coal to liquids (CTL) and coal-biomass to liquids (CBTL) processes were advanced by testing and demonstrating Southern Research’s sulfur tolerant nickel-based reforming catalyst and Chevron’s highly selective and active cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst to clean, upgrade and convert syngas predominantly to jet fuel range hydrocarbon liquids, thereby minimizing expensive cleanup and wax upgrading operations. The National Carbon Capture Center (NCCC) operated by Southern Company (SC) at Wilsonville, Alabama served as the host site for the gasifier slip-stream and simulated syngas testing/demonstration. Reformer testing was performed to (1) reform tar and light hydrocarbons, (2) decompose ammonia in the presence H2S, and (3) deliver the required H2 to CO ratio for FT synthesis. FT Testing was performed to produce a product primarily containing C5-C20 liquid hydrocarbons and no C21+ waxy hydrocarbons with productivity greater than 0.7 gC5+/g catalyst/h, and at least 70% diesel and jet fuel range (C8-C20) hydrocarbon selectivity in the liquid product. A novel heat-exchange reactor system was employed to enable the use of the highly active FT catalyst and larger diameter reactors that results in cost reduction for commercial systems. Following laboratory development and testing, SR’s laboratory reformer was modified to operate in a Class 1 Div. 2 environment, installed at NCCC, and successfully tested for 125 hours using raw syngas. The catalyst demonstrated near equilibrium reforming (~90%) of methane and complete reforming/decomposition of tar and ammonia in the presence of up to 380 ppm H2S. For FT synthesis, SR modified and utilized a bench scale skid mounted FT reactor system (SR-CBTL test rig) that was fully integrated with a slip stream from SC/NCCC’s transport gasifier (TRIG). The test-rig developed in a previous project (DE-FE0010231) was modified to receive up to 7.5 lb/h raw syngas augmented with bottled syngas to adjust the H2/CO molar ratio to 2, clean it to cobalt FT catalyst specifications, and produce liquid FT products at the design capacity of up to 6 L/day. Promising Chevron catalyst candidates in the size range from 70-200 μm were loaded onto SR’s 2-inch ID and 4-inch ID bench-scale reactors utilizing IntraMicron’s micro-fiber entrapped catalyst (MFEC) heat exchange reactor technology. During 2 test campaigns, the FT reactors were successfully demonstrated at NCCC using syngas for ~420 hours. The catalyst did not experience deactivation during the tests. SR’s thermo-syphon heat removal system maintained reactor operating temperature along the axis to within ±4 °C. The experiments gave a steady catalyst productivity of 0.7-0.8 g/g catalyst/h, liquid hydrocarbon selectivity of ~75%, and diesel and jet fuel range hydrocarbon selectivity in the liquid product as high as 85% depending on process conditions. A preliminary techno-economic evaluation showed that the SR technology-based 50,000 bpd plant had a 10 % lower total plant cost compared to a conventional slurry reactor based plant. Furthermore, because of the modular nature of the SR technology, it was shown that the total plant cost advantage increases to >35 % as the plant is scaled down to 1000 bpd.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2022

Development of Carbon Molecular Sieves Hollow Fiber Membranes based on Polybenzimidazole Doped with Polyprotic Acids with Superior H 2 /CO 2 Separation Properties (Final Report)

The goal of this project was to develop a highly efficient membrane-based process to capture CO 2 from coal-derived syngas with 95% CO 2 purity, achieving the cost of electricity (COE) 30% below the baseline capture approaches (i.e., Selexol process) when coupled with the advancement in other areas of the power generation facility. Our core approach is based on high-permeance hollow fiber membranes (HFMs) with superior H 2 /CO 2 separation properties at the syngas process conditions, which can then be further utilized to design membrane reactors for process intensification of H 2 production and purification and CO 2 capture. Three organizations with complementary skills collaborated to achieve the goal, including the University at Buffalo (UB), Los Alamos National Laboratory (LANL), and Trimeric Corporation (Trimeric). We formulated logical steps to bring the membrane technology from Technology Readiness Level (TRL) 3 (Experimental proof of concept) to TRL 4 (Laboratory scale validation in relevant environment). During the budget period (BP) 1, we screened various polymeric materials and identified polybenzimidazole doped with inorganic polyprotic acids as the desirable platform. The acid doping increases the H 2 /CO 2 selectivity, and the sequential carbonization increases H 2 permeability while retaining the high selectivity. By manipulating the acid type and doping level and the carbonization temperature, we demonstrated advanced carbon molecular sieving (CMS) materials with H 2 permeability of above 200 Barrer (1 Barrer = 10 -10 cm 3 (STP) cm cm -2 s -2 cmHg -1 ) and H 2 /CO 2 selectivity of above 40 at 200-300°C with simulated syngas containing CO and water vapor. For example, the PBI-(H 3 PO 4 ) 0.11 carbonized at 700 °C exhibits H 2 permeability of 200 Barrer and H 2 /CO 2 selectivity of 60 at 200 °C, and H 2 permeability of 240 Barrer and H 2 /CO 2 selectivity of 54 at 225 °C, which meets the targeted properties and surpasses Robeson’s upper bound. During the BP2, we focused on the conversion of the advanced CMS materials to stable HFMs. Membranes with H 2 permeance of 1,090 GPU (1 GPU = 10 -6 cm 3 (STP) cm -2 s -2 cmHg -1 ) and H 2 /CO 2 selectivity of 57 at 300 °C were successfully fabricated. The effects of temperature, gas compositions, pressure, and time on the separation properties were systematically investigated. Pencil modules were continuously evaluated for 219 h (dry pure gas) and 669 h (dry simulated syngas) and showed initial decline in permeance and increased H 2 /CO 2 selectivity over time, ultimately achieving a steady state stable value, indicating that the ageing phenomena in the nanoporous structures of the membranes during the test. Membrane reactors were fabricated based on the CMS membranes and evaluated for water-gas shift (WGS) reaction. The use of membranes slightly improves the conversion of the CO. However, parametric tests of the membrane reactors at various temperatures and flow rates need to be conducted, as well as the membranes with improved separation performance. We performed a sensitivity analysis on the impact of H 2 /CO 2 selectivity on the COE based on a hybrid process of a membrane unit and cryogenic unit developed by Membrane Technology and Research, Inc. (MTR). Three H 2 /CO 2 selectivity (40, 60, and 15) cases were developed and compared with the baseline capture process (Case B5B) provided by the DOE report. Increasing the membrane H 2 /CO 2 selectivity reduces COE, but the rate of the decrease of COE also diminishes. The COE values for H 2 /CO 2 selectivities of 40 and 60 were nearly the same. As the H 2 /CO 2 selectivity increases, the inert recycling decreases, leading to smaller equipment, less auxiliary power requirements, and less heating, cooling, and refrigeration duty. The refrigeration system used to liquefy the CO 2 is the most expensive piece of equipment and consumes the most electricity within the CO 2 capture process. Increasing the CO 2 concentration in the recycle stream would improve the economics of the process by reducing the refrigeration duty requirement of the unit and also allow for higher liquefaction temperatures. The high H 2 -selective membrane developed by our team may be applicable in other separation processes where lower pressure H 2 retains value. Typically, hydrogen retains its pressure when it is separated from syngas components. Residual components may be used as low-quality fuel and then vented to the atmosphere. Applications might include control of H 2 /CO ratios or mitigation of the water gas shift reaction by CO 2 recycling to the feed of a gasifier or steam methane reformer. To summarize, we have developed industrial HFMs with the best H 2 /CO 2 separation performance reported in the literature. The membranes demonstrate stability with simulated syngas and show great potential for membrane reactors for WGS reactions, lowering the cost of blue H 2 production.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2012

Preparation and testing of corrosion and spallation-resistant coatings

This Energy & Environmental Research Center (EERC) project is designed to determine if plating APMT, a specific highly oxidation-resistant oxide dispersion-strengthened FeCrAl alloy made by Kanthal, onto nickel-based superalloy turbine parts is a viable method for substantially improving the lifetimes and maximum use temperatures of the parts. The method for joining the APMT plate to the superalloys is called evaporative metal bonding. It involves placing a thin foil of zinc (Zn) between the plate and the superalloy, clamping them together, and heating in an atmosphere-controlled furnace. Upon heating, the Zn melts and dissolves the oxide skins of the alloys at the bond line, allowing the two alloys to diffuse into each other. The Zn then diffuses through the alloys and evaporates from their surfaces. Laboratory testing has shown that the diffusion rate of Zn through the FeCrAl alloy is much faster than through the nickel superalloys. This means that the FeCrAl will serve as a sink for the Zn bonding alloy during the evaporative metal bonding process. Also, the testing has shown that the Zn diffusion mechanism is bulk diffusion, and not intergranular. This is a surprise. However, it means that quantification of the Zn diffusivities in these samples will be significantly simpler than would have been the case if grain boundary diffusion dominated. In addition to the laboratory testing, gas impinger and particulate samples are being collected from a combustor firing syngas and natural gas to determine what types of microcontaminants may reach a turbine firing syngas. The syngas is created in one of two different pilot-scale pressurized coal gasifiers. The initial analysis of the impinger solutions was for standard U.S. Environmental Protection Agency (EPA) Method 29 determination of hazardous metals and did not include major element analysis. When syngas is fired, the amount of Mn in the combustor gas increases substantially. Halogens (Br2 and Cl2) and hydrogen halides (HF, HCl, and HBr) are present in amounts close to or below 1 ppm. In the near future, the solutions will be reanalyzed for major elements. SEM analysis showed that the particulate matter is primarily nonstoichiometric iron sulfate. Most of the particles were 3 μm in diameter or less. Elements such as O, Fe, S, Cr, and Si make up the majority of the compositions of 3089 particles analyzed on the filter surface. The concentrations of O and S are high in almost all particles. The concentrations of S and Fe tend to be higher in the larger particles than in the smaller. In contrast the concentrations of O showed the reverse trend. We currently believe that the high values of Fe and Cr come from a reaction of the syngas with the stainless steel pipes used to transport the syngas, most likely by forming a vapor-phase carbonyl. During combustion, the carbonyls form nonstoichiometric sulfate particles. The excess Si is most likely coming from the coal ash, possibly through the formation of a silicon monoxide fume.

Electric↗
DOE OSTI2019

Effects of reformed fuel on dual-fuel combustion particulate morphology

Advancements in catalytic reforming have demonstrated the ability to generate syngas (a mixture of CO and hydrogen) from a single hydrocarbon stream. This syngas mixture can then be used to replace diesel fuel and enable dual-fuel combustion strategies. The role of port-fuel injected syngas, composed of equal parts hydrogen and carbon monoxide by volume, was explored experimentally for soot reduction benefits under diesel pilot ignition and reactivity controlled compression ignition strategies. Particle size distribution measurements were made with a scanning mobility particle sizer and condensation particle counter for different levels of syngas substitution. To explain the experimental findings, computational fluid dynamics simulations utilizing a detailed stochastic soot model were used to validate and initialize additional simulations that isolate mixing and chemistry effects. Based on these simulations, the influence of adding syngas on soot particle size and quantity is discussed.

42 ENGINEERING↗
DOE OSTI2014

CAS-NETL-PNNL CEP Program Final Report

This collaborative joint research project is in the area of advanced gasification and conversion, within the CAS-NETL-PNNL Memorandum of Understanding. The goal is the development and testing of an integrated warm syngas cleanup process. This effort is focused on an advanced, integrated system for capture and removal of alkali, sulfur, PH3, AsH3, chloride, and CO2, leading to a future process demonstration at a CAS gasification facility. Syngas produced by gasification can be used for production of fuels (Fischer-Tropsch, SNG, mixed alcohols), chemicals (MeOH, NH3), and hydrogen for fuel cells and IGCC. To employ this syngas, especially for synthesis reactions, contained impurities must be removed to sub-ppmv levels [1]. Commercially available approaches to remove contaminant species suffer from inefficiencies, employing solvents at ambient or lower temperature along with backup sacrificial sorbents, whereas syngas utilization occurs at higher temperatures. The efficiency and economics syngas utilization can be significantly improved if all the contaminants and CO2 are removed at temperatures higher than the chemical synthesis reaction temperatures (> 250 °C) [2].

alkali↗
DOE OSTI2012

Modelling of a downdraft gasifier fed by agricultural residues

Highlights: Black-Right-Pointing-Pointer Development of software for downdraft gasification simulation. Black-Right-Pointing-Pointer Prediction of the syngas concentration. Black-Right-Pointing-Pointer Prediction of the syngas heating value. Black-Right-Pointing-Pointer Investigation of the temperature effect in reduction zone in syngas concentration. - Abstract: A non-stoichiometric model for a downdraft gasifier was developed in order to simulate the overall gasification process. Mass and energy balances of the gasifier were calculated and the composition of produced syngas was predicted. The capacity of the modeled gasifier was assumed to be 0.5 MW, with an Equivalence Ratio (EQ) of 0.45. The model incorporates the chemical reactions and species involved, while it starts by selecting all species containing C, H, and O, or any other dominant elements. Olive wood, miscanthus and cardoon were tested in the formulated model for a temperature range of 800-1200 Degree-Sign C, in order to examine the syngas composition and the moisture impact on the supplied fuel. Model results were then used in order to design an olive wood gasification reactor.

09 BIOMASS FUELS↗
DOE OSTI2012

Hydrogen Production and Purification from Coal and Other Heavy Feedstocks Year 6 - Activity 1.4 - Development of a National Center for Hydrogen Technology

Air Products and Chemicals, Inc., is developing the sour pressure swing adsorption (PSA) technology which can be used to reject acid gas components (hydrogen sulfide [H 2 S] and carbon dioxide [H 2 S]) from sour syngas streams such as coal gasification syngas. In the current work, tests were conducted to investigate the impact of continuous exposure of real sour syngas and dilute levels of hydrochloric acid (HCl) and ammonia (NH 3 ) on the preferred adsorbent of that process. The results show a modest (~10%–15%) decrease in CO 2 adsorption capacity after sour syngas exposure, as well as deposition of metals from carbonyl decomposition. Continuous exposure to HCl and NH 3 yield a higher degree of CO 2 capacity degradation (up to 25%). These tests represent worst-case approaches since the exposure is continuous and the HCl and NH 3 levels are relatively high compare to an industrial sour syngas stream. Long-term PSA tests are needed to unequivocally evaluate the impact of cyclic exposure to these types of streams.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

Water-Gas-Shift Membrane Reactor for High-Pressure Hydrogen Production. A comprehensive project report (FY2010 - FY2012)

Idaho National Laboratory (INL), GE Global Research (GEGR), and Western Research Institute (WRI) have successfully produced hydrogen-selective membranes for water-gas-shift (WGS) modules that enable high-pressure hydrogen product streams. Several high performance (HP) polymer membranes were investigated for their gas separation performance under simulated (mixed gas) and actual syngas conditions. To enable optimal module performance, membranes with high hydrogen (H 2 ) selectivity, permeance, and stability under WGS conditions are required. The team determined that the VTEC PI 80-051 and VTEC PI 1388 (polyimide from Richard Blaine International, Inc.) are prime candidates for the H 2 gas separations at operating temperatures (~200°C). VTEC PI 80-051 was thoroughly analyzed for its H 2 separations under syngas processing conditions using more-complex membrane configurations, such as tube modules and hollow fibers. These membrane formats have demonstrated that the selected VTEC membrane is capable of providing highly selective H 2 /CO 2 separation (α = 7-9) and H 2 /CO separation (α = 40-80) in humidified syngas streams. In addition, the VTEC polymer membranes are resilient within the syngas environment (WRI coal gasification) at 200°C for over 1000 hours. The information within this report conveys current developments of VTEC PI 80-051 as an effective H 2 gas separations membrane for high-temperature syngas streams.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Fuel Flexible Turbine System (FFTS) Program

In this fuel flexible turbine system (FFTS) program, the Parker gasification system was further optimized, fuel composition of biomass gasification process was characterized and the feasibility of running Capstone MicroTurbine(TM) systems with gasification syngas fuels was evaluated. With high hydrogen content, the gaseous fuel from a gasification process of various feed stocks such as switchgrass and corn stover has high reactivity and high flashback propensity when running in the current lean premixed injectors. The research concluded that the existing C65 microturbine combustion system, which is designed for natural gas, is not able to burn the high hydrogen content syngas due to insufficient resistance to flashback (undesired flame propagation to upstream within the fuel injector). A comprehensive literature review was conducted on high-hydrogen fuel combustion and its main issues. For Capstone's lean premixed injector, the main mechanisms of flashback were identified to be boundary layer flashback and bulk flow flashback. Since the existing microturbine combustion system is not able to operate on high-hydrogen syngas fuels, new hardware needed to be developed. The new hardware developed and tested included (1) a series of injectors with a reduced propensity for boundary layer flashback and (2) two new combustion liner designs (Combustion Liner Design A and B) that lead to desired primary zone air flow split to meet the overall bulk velocity requirement to mitigate the risk of core flashback inside the injectors. The new injector designs were evaluated in both test apparatus and C65/C200 engines. While some of the new injector designs did not provide satisfactory performance in burning target syngas fuels, particularly in improving resistance to flashback. The combustion system configuration of FFTS-4 injector and Combustion Liner Design A was found promising to enable the C65 microturbine system to run on high hydrogen biomass syngas. The FFTS-4 injector was tested in a C65 engine operating on 100% hydrogen and with the redesigned combustion liner - Combustion Liner Design A - installed. The results were promising for the FFTS program as the system was able to burn 100% hydrogen fuel without flashback while maintaining good combustion performance. While initial results have been demonstrated the feasibility of this program, further research is needed to determine whether these results will be repeated with FFTS-4 injectors installed in all injector ports and over a wide range of operating conditions and fuel variations.

42 ENGINEERING↗