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Richards, George

Publications and source records attributed to Richards, George.

9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Abstract for CRADA between the National Energy Technology Laboratory and Strategic Power Systems, Inc. (AGMT-0884)

This project will utilize field data, available through the Operational Reliability Analysis Program (ORAP®), to assess the operation of natural gas combined cycle (NGCC) and coal fired plants in cyclic duty. The emphasis will be on Heat Recovery Steam Generator (HRSG) and coal-fired boiler operating conditions and failure experience related to tube failures. The project will be based on high-fidelity data available in ORAP through the collection of near real time process data characterizing the operating environment and dynamic conditions, from start up to shut-down, that affect the HRSG and coal-fired boiler (i.e. the boiler tubes). It is important to understand the operating environment to assess the influence of the cyclic start-stop cycles, time at temperature, and other operating conditions that can be seen in the data, with their possible impact on the life and reparability of the boiler tubes. This knowledge is important to influence/develop a predictive operations and maintenance strategy to improve performance, increase life, and reduce cost.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2019

Production of hydrogen by steam oxidation of calcium ferrite reduced with various coals

Production of H 2 by steam oxidation was demonstrated with calcium ferrite (CaFe 2 O 4 ) after coal gasification to produce CO with several types of coals. All coal types reacted with CaFe 2 O 4 to produce CO. The reduced CaFe 2 O 4 after the reaction with coal can also be oxidized with steam at 800 °C while producing of H 2 . Sub-bituminous coal and lignite coal had better reactivity with CaFe 2 O 4 than the bituminous coal. A ten-cycle test conducted with Wyodak coal/CaFe 2 O 4 at 800 °C showed stable production of H 2 during oxidation with steam. A 25-cycle steam oxidation test conducted after reduction of CaFe2O4 with lignite coal also showed a very stable performance. Steam oxidation is sufficient for maintaining the cyclic reactions. A larger scale (2 kg batch) production of CaFe 2 O 4 by wet granulation-tumbling method was successful. In conclusion, steam oxidation was demonstrated with the large-scale batch of CaFe 2 O 4 after reduction with Wyodak coal.

08 HYDROGEN↗
DOE OSTI2018

50-kWth methane/air chemical looping combustion tests with commercially prepared CuO-Fe 2 O 3 -alumina oxygen carrier with two different techniques

CuO-Fe 2 O 3 /alumina oxygen carriers were manufactured using two different techniques (i.e., spray drying and wet granulation). The spray drying method produced porous, spherical particles in the range of 100–200 µm. The wet granulation, or tumbling method, produced particles in the range of 200–600 µm. Both batches of material showed good gas conversion and particle durability during tests in NETL’s 50-kWth chemical looping circulating fluidized bed combustor unit at 700–900 °C. No agglomeration was observed, even though the oxygen carrier had a high CuO concentration (30%). The particle losses with 200–600 µm batch were significantly lower than that with the 100–200 µm batch. The oxygen carrier materials in the 200–600 µm range were circulated for approximately 3.1 days in the target temperature range (700–850 °C) and a total of approximately 40 h of chemical looping combustion testing was conducted during that time. The average fuel reactor temperatures ranged from 760 to 815 °C for the chemical looping combustion test periods, and the average air reactor temperature ranged from 840 to 915 °C. The fuel conversion from natural gas to CO 2 ranged from 50 to 80%. Approximately 1.6 h of continuous operation was achieved with no gas preheat and no natural gas augmented heating. During this test period, the average fuel reactor temperature ranged from 780 to 825 °C, the air reactor temperature ranged from 930 to 960 °C, and the natural gas to CO 2 conversion ranged from 50 to 65%. Finally, analysis of the oxygen carrier after the test indicated that there were no significant changes in the particle size or the surface morphology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe 2 O 3 -alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier. Reactions of coal/steam/CuO-Fe 2 O 3 -alumina oxygen carrier and coal/steam/partially reduced CuO-Fe 2 O 3 -alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). In addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H 2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H 2 was also observed with the reduced oxygen carrier. CuO-Fe 2 O 3 -alumina reacted with coal during the temperature ramp to 850 °C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Here, the fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Chemical looping coal gasification with calcium ferrite and barium ferrite via solid--solid reactions

Coal gasification to produce synthesis gas by chemical looping was investigated with two oxygen carriers, barium ferrite (BaFe2O4) and calcium ferrite (CaFe2O4). Thermo-gravimetric analysis (TGA) and fixed-bed flow reactor data indicated that a solid–solid interaction occurred between oxygen carriers and coal to produce synthesis gas. Both thermodynamic analysis and experimental data indicated that BaFe2O4 and CaFe2O4 have high reactivity with coal but have a low reactivity with synthesis gas, which makes them very attractive for the coal gasification process. Adding steam increased the production of hydrogen (H2) and carbon monoxide (CO), but carbon dioxide (CO2) remained low because these oxygen carriers have minimal reactivity with H2 and CO. Therefore, the combined steam–oxygen carrier produced the highest quantity of synthesis gas. It appeared that neither the water–gas shift reaction nor the water splitting reaction promoted additional H2 formation with the oxygen carriers when steam was present. Wyodak coal, which is a sub-bituminous coal, had the best gasification yield with oxygen carrier–steam while Illinois #6 coal had the lowest. The rate of gasification and selectivity for synthesis gas production was significantly higher when these oxygen carriers were present during steam gasification of coal. The rates and synthesis gas yields during the temperature ramps of coal–steam with oxygen carriers were better than with gaseous oxygen.

01 COAL, LIGNITE, AND PEAT↗