Optimization of the Sour Compression Unit (SCU) process for CO2 purification applied to flue gases coming from oxy-combustion cement industries

摘要

In the context of Carbon Capture Storage (CCS) or Utilization (CCU), the application of a CO2 Purification Unit (CPU) previously developed for oxyfuel power plants is here tested on flue gases coming from oxyfuel cement plants thanks to simulations with Aspen Plus?. The CPU block is divided into three CO2 purification steps. The compressed gas is firstly desulfurized and denitrified in a double-column (operating at 15 bar for the first column and 30 bar for the second one) unit called "Sour-Compression Unit" (SCU) where it is purified counter-currently with water to remove SO_x and NO_x components by a reactive absorption. Further treatments include a water adsorption step, and finally a separation step using either a distillation column or a double flash unit, to remove the residual inert gases. The present communication will be focused on the first step of the CPU, the "Sour-Compression Unit". For this purpose, an accurate chemical mechanism was constructed based on literature reviews and critical comparison of various sources in order to represent properly the removal of SOx and NOx components and evaluate the performances of the SCU. Simulation results of this quite innovative application to cement plant flue gases are given and discussed. Future works will include an energetic and economic optimization of the SCU for the cement plant case.