Development of an adsorption process for pre-combustion CO₂ capture

Abstract

The carbon dioxide (CO2) emissions originating from the combustion of fossil fuels (e.g. coal) in power plants represent a considerable environmental problem as they are among the main causes of global warming and climate change. Bearing in mind the increasing energy requirement worldwide a complete substitution of fossil fuels will not be feasible within the near future, hence other solutions to reduce CO2 emissions have to be found urgently. The so-called IGCC technology (Integrated Gasification Combined Cycle) with pre-combustion CO2 capture represents a promising approach for near-zero CO2 emission power plants to be realized in the near future. A key challenge within this technology is the separation of the CO2 / H2 gas mixture resulting form the gasification of coal followed by the water gas shift reaction. The efficiency of this step is critical to minimize the energy penalty of the capture process and to enable this strategy. In contrast to post-combustion capture from power plants, where a large gas stream at low pressure and low CO2 content has to be treated, in pre-combustion capture an adsorption based process, especially pressure swing adsorption (PSA), is a possible method for CO2 removal from H2. For the investigation of this possibility, three different aspects have to be considered: