A novel flue gas pre-treatment system of post-combustion CO2 capture in coal-fired power plant

Abstract

A novel flue gas pre-treatment system for post-combustion CO2 capture (PCC) in coal-fired power plant was proposed to simultaneously reduce energy and water consumption. A flash evaporation device (FE) and mechanical vapour compressor (MVC) were utilised to provide low-temperature water for washing and cooling flue gas, collect recovered water, and absorb recovered latent heat from flue gas. The system successfully decreased flue gas temperature and moisture content, and provided heat for solvent regeneration to reduce regeneration energy consumption. The Aspen Plus’ rate-based model was used to simulate reference and novel systems based on a 300MW coal-fired power plant. The results indicate that energy consumption in the one- and two-stage CO2 capture systems decreased by 16.3% and 20.6%, respectively. To achieve lower energy consumption, key parameters of the two-stage CO2 capture system were optimised through simulation. The energy consumption of the system with the optimum parameters was 22.5% less than the reference system. Furthermore, water consumption was 27.9% lower than that of the reference system. This novel system has the potential to reduce energy and water consumption in coal-fired power plants with PCC.