Air separation and flue gas compression and purification units for oxy-coal combustion systems

Air Liquide (AL) has been actively involved in the development of oxy-coal technologies for CO2 capture from power plants for the past 5 years. Large systems for oxygen production and flue gas purification are required for this technology. Air Liquide has been a leader in building large Air Separation Units (ASUs) and more developments have been performed to customize the air separation process for coal-fired power plants. Air Liquide is also actively involved in developing processes for purification of flue gas from oxy-coal combustion systems for enhanced oil recovery applications as well as sequestration in saline aquifers. Through optimization of the cryogenic air separation process for oxy-coal combustion, a 20% reduction in the separation energy requirement of the ASU has been achieved. Several CO2 capture schemes have been developed to study the energy requirement to achieve CO2 product streams meeting different specifications. Utilization of waste heat from both the ASU and CO2 capture unit for heating boiler feed water has been shown to significantly improve the energy efficiency of the overall process.