Process Simulation and Cost Optimization of a Gas based Power Plant including amine based CO2 Capture

Abstract

CO2 capture from gas turbine exhaust gas using heat from the power generation cycle is a possibility for CO2 emission reduction from natural gas-based power plants. A simplified power plant was simulated in Aspen HYSYS with a compressor, a combustion chamber, a turbine, a steam circuit with a steam heater, a high-pressure steam turbine, a low-pressure steam turbine, a steam condenser, and a circulating pump. CO2 capture was simulated with an absorption column, a rich amine pump, a lean/rich amine heat exchanger, a desorber with a reboiler and condenser, a lean pump and an amine cooler. The equipment cost was obtained from Aspen In-plant Cost Estimator, and an enhanced detailed factor method was used to estimate the total investment. A base case with combustion at 30 bar, ΔTMIN of 10 °C, and 10 stages (meters of absorber packing) was simulated, dimensioned, and cost estimated. In earlier works, optimum parameters have been found by minimizing the cost of CO2 capture. In this work, optimum was defined as the maximum profit for a combined process with 85 % capture efficiency. Optimized parameters were calculated to 25 bar for the combustion pressure, 13 °C for the minimum temperature approach in the lean/rich amine heat exchanger, and 10-meter packing height in the absorption column. These values are comparable to values in literature.