CO_2 SEQUESTRATION FROM SOLID OXIDE FUEL CELLS: TECHNICAL OPTIONS AND COSTS

摘要

This paper discusses technical and economical aspects of using Solid Oxide Fuel Cells (SOFC) for CO_2 sequestration. Specifically, we present a conceptual design study involving the combination of a 20 MW SOFC with an electrochemical afterburner (ECAB) to reach the high CO_2 concentration of about 90 mol-% in the exhaust gas that is required for efficient CO_2 sequestration. A commercial simulation program (PRO/II) is used to quantify the influences of flow-sheet variations on plant efficiency and costs. Particularly the process variants involve different types of ECABs (oxygen pump, mixed oxide conductor and second SOFC) and different possibilities of turbine integration into the cooling air system of the SOFC/ECAB generator. By comparison with a conventional reference system without CO_2 capture (gas turbine system) CO_2 abatement costs are calculated and economic break-even points on a scale of increasing CO_2 tax values, expected for the future, are determined.