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Fixed bed gasification of corn stover biomass fuel: Egypt as a case study

Abstract:

This paper focuses on the optimal performance of a small tri-generation power, heat, and cooling plant, which uses corn stover as the feedstock. First, 100 kg h−1 of the corn stover is converted into syngas by the gasification process, using a downdraft fixed-bed reactor at gasification temperatures reaching 995 °C and with an oxidant–fuel ratio of 1.65. About 243.18 kg h−1 of product gas mass flow with 4.766 MJ kg−1 of calorific value is supplied to an externally fired gas turbine (EFGT) to convert this fuel to electrical power. It is estimated that the EFGT is capable of producing 70.57 kW of electrical power with a high-temperature heat exchanger efficiency of 75% and a pressure ratio of 4.84 at a turbine inlet temperature of 875 °C. The absorption refrigeration system is used for the cooling process. The cooling power (ℚ eva) of the absorption cooling system is 130.92 kW with a cooling tower temperature of 15 °C and a system performance coefficient (PC) of 0.6. The recovered heat flow to the generator (ℚ gen) and the refrigerating heat flow are 82.62 kWth and 48.83 kWref, respectively, with a circulation ratio of 4.07. For the whole system (gasifier, EFGT, and absorption cooling), the gross electrical efficiency (ηnetEL) is 21.78% and the net thermal efficiency (ηth) is 47.43% with a system cooling-to-power ratio (CPR) of 1.88. The simulation of this system was conducted using Cycle-Tempo software. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.