Status of MWth Integrated Gasification Fuel Cell (IGFC) Power Generation System Demonstration in China

Abstract

Abstract This paper provides status update of IGFC power generation system being developed at National Institute of Clean-and-Low-Carbon (NICE) at MW th scale. This system is designed to use coal as fuel to produce syngas as a first step similar to integrated gasification combined cycles (IGCC). Subsequently, the solid oxide fuel cell system is used to convert chemical energy to electricity electrochemically without combustion, which is different from IGCC. This system leads to a higher efficiency as compared to a traditional coal-fired power plant. The unreacted fuel in the SOFC system is transported to an oxygen-combustor to be converted to steam and CO 2 . Through heat recovery system, the steam is condensed and removed, and CO 2 is enriched and captured for sequestration or other application, such as co-electrolysis of CO 2 and H 2 O using curtailed renewable energy for production of syngas. Comprehensive economic analysis for a typical IGFC system was performed and the results were compared with supercritical pulverized coal-fired (SCPC) power plant, showing the cost of electricity (COE) of IGFC could be up to 20% lower than that by SCPC with CO 2 capture. The SOFC stacks selected for IGFC development were tested and qualified under both hydrogen and simulated coal syngas fuel showing good consistency and stable long term performance. Experimental results using SOFC stacks and thermodynamic analysis (using ASPEN Plus) indicate that the hydrogen to CO ratio of the syngas is preferred to be 1.68 or higher to avoid carbon deposition inside of the fuel pipe. For lower H 2 /CO ratio, steam to CO ratio needs to be higher. Besides, the steam needs to be mixed well with the syngas above 100 °C and below the temperatures where carbon formation is thermodynamically favored. The 20kW SOFC power generation unit is being developed with design system conditions of 20 kW maximum power, current density of 0.334 A/cm 2 , DC efficiency of 50.41%, and fuel utilization of 80%. A 100kW subsystem will consist of 6 x 20kW power generation units, and the MW th IGFC system will consist of 5 x 100kW sub-systems.

Key findings

• ▸The IGFC system uses coal as fuel to produce syngas, then converts it to electricity electrochemically in a solid oxide fuel cell system.
• ▸The unreacted fuel in the SOFC system is converted to steam and CO2, which is then captured and enriched for sequestration or other applications.
• ▸The comprehensive economic analysis showed that the cost of electricity (COE) of IGFC could be up to 20% lower than that of supercritical pulverized coal-fired (SCPC) power plants with CO2 capture.

Keywords

Identifiers

DOI

10.21203/rs.3.rs-27942/v1

Journal

Research Square

Year

2020