An Exploratory Study of an Oxyfuel Combustion Turbine Cycle With Vapor Absorption Refrigeration and Water Production

The preliminary findings of an exploratory study conducted on a novel Oxyfuel Combustion Turbine Cycle (OCTC) using ASPEN PLUS for a range of 40% to 90% CO2 capture are presented. Starting from a GE Energy IGCC, the OCTC retains the Gasifier with a Radiant Cooler-only section and the Warm-Gas-Clean Up (WGCU) section with the desulfurization process eliminated for a combined carbon and sulfur co-sequestration approach. The conventional gas turbine combined cycle is also removed. With no integration between the Air Separation Unit (ASU) and the modified oxyfuel combustion turbine, the High Pressure (HP) ASU is replaced by a Low pressure (LP) ASU. The added attributes of this novel coal-based power system configuration are (1) the Vapor Absorption Refrigeration System (VARS), (2) the associated water production in the VARS evaporator, (3) the recirculation of combustor flue gas for lower NOx emissions and additional power production, as well as (4) an original concept of carbon dioxide compression as proposed by SouthWest Research Institute (SwRI) and Dresser Rand (D-R). Assuming a reasonable Coefficient of Performance (COP) for the VARS, the overall process efficiency results (about 35% HHV) were equivalent or even better when compared with studies of current simulated IGCC systems with CO2 capture. Once an optimum scheme has been finalized in future activities, an economic analysis would be conducted. The combined performance and economic results could then be compared with alternate advanced coal based power systems.Copyright © 2009 by ASME