The oxygen production pre-combustion (OPPC) IGCC plant for efficient power production with CO2 capture

Abstract

This work presents a novel integrated gasification combined cycle (IGCC) power plant configuration for CO2 capture with minimal energy penalty. The proposed oxygen production pre-combustion (OPPC) power plant synergistically integrates a gas switching oxygen production (GSOP) unit into a pre-combustion IGCC power plant, reducing the energy penalty through two channels: 1) avoidance of a cryogenic air separation unit and 2) pre-heating the air sent to the combined power cycle, which reduces the steam requirement for shifting CO to H2 and the CO2 capture duty involved in pre-combustion CO2 capture. Relative to a conventional pre-combustion IGCC benchmark, the OPPC configuration improves the electric efficiency by about 6%-points, although the CO2 capture ratio reduces by about 6%-points. OPPC as avoids the maximum temperature limitation of Chemical Looping Combustion based plants, and can therefore benefit from efficient modern gas turbine technology operating at very high inlet temperatures. CO2 removal via physical absorption (Selexol) generally results in higher efficiencies, but lower CO2 avoidance than chemical absorption (MDEA). Plant efficiency also benefits from an increase in GSOP operating temperature, although the maximum temperature was limited to 900 °C to avoid any temperature-related challenges with oxygen carrier stability or downstream valves and filters. OPPC therefore appears to be a promising configuration for minimizing the energy penalty of CO2 capture in IGCC power plants, combining well known and proven technology blocks with a GSOP reactor cluster instead of an ASU.