Post-Combustion CO2 Capture Using Solid Sorbents: 1 MWe Pilot Evaluation

Abstract

Carbon dioxide capture and storage (CCS) is anticipated to be an important component of reducing worldwide CO2 emissions from stationary point sources, such as coal-fired power plants. One of the most important challenges to the widespread implementation of CCS is the cost and energy associated with the separation of CO2 from flue gas. Aqueous amines and ammonia are being demonstrated by several groups for CO2 capture in a temperature swing cyclic process. Solid sorbents can also be used in a similar temperature swing process, but have the potential to reduce the overall costs related to CO2 capture by reducing the energy required to release the CO2 during material regeneration due to less evaporation of water and lower specific heat capacity. In addition, laboratory experiments conducted to date have demonstrated that a greater CO2 working capacity (defined as the difference between the CO2 loading at adsorption conditions and CO2 loading at regeneration conditions) can be achieved versus those reported for aqueous monoethanol amine (MEA) temperature swing systems, using commercially available sorbents. However, such CO2 working capacities on dry sorbents have yet to be demonstrated beyond the lab- and bench-scale. Therefore, while most development efforts are directed toward sorbent development, ADA Environmental Solutions (ADA) has focused on development and demonstration of the related process and equipment.Several different reactors utilized for gas/solids contacting were considered by ADA for the CO2 adsorption and sorbent regeneration. The reactors evaluated included: fixed beds, transport reactors, moving beds, trickle down reactors, and staged fluidized beds. Working with engineers from Shaw Energy & Chemicals (now part of Technip, a world leader in project management, engineering, and construction for the energy industry), ADA selected staged fluidized beds for adsorption and a single fluidized bed for regenerating the sorbent; this decision was mainly based on optimizing heat transfer in the system. A majority of the project funds are being provided by the DOE National Energy Technology Program (formerly referred to as the Innovations for Existing Plants Program).