The Radovich Cycle: A Novel MSW-Fired Heat Cycle

A conceptual study was performed for a novel heat cycle designed to utilize fuel gases produced by a Taylor Biomass Energy (TBE) Gasification System. The system is sized to consume 500 dry tons per day Municipal Solid Waste (MSW). The heat cycle utilizes a Solid Oxide Fuel Cell (SOFC) feeding directly to a Twin-Fluidized Bed Steam Gasification Unit (TFBSGU). MSW fed into the TFBSGU is partially gasified by exhaust from the anode space of the fuel cell. The resulting gas is cooled, sour-shifted, dehydrated and compressed. The compressed gas passes through an acid-gas removal (AGR) system and then is returned to the anode space of the fuel cell. Combustion air is compressed and passes through the cathode space of the fuel cell before entering the TFBSGU in a separate stream from the fuel gas. The resulting flue gas leaves the TFBSGU and is cooled and expanded before exhausting to atmosphere. The design also features sour shift and acid gas removal from the fuel stream. The plant produces 44 net MW, converting approximately 43% of the energy in the MSW into electricity and 23% of the energy into usable thermal energy. Overnight 2009 EPC costs are estimated at $6000/net kw. Electrical production costs are estimated at 126$/MWhr. Because the plant burns MSW, it provides carbon offsets. In addition, approximately 60% of the carbon dioxide produced by the plant can be readily sequestered. The conceptual design included a heat balance, water balance, auxiliary load list, capital cost estimate, and cost of electricity estimate.