Partial oxy-combustion technology for energy efficient CO2 capture process

Abstract

Partial oxy-combustion is considered a promising carbon capture and storage technology that can lead to further energy penalty reductions. The presence of large amounts of CO2 in the flue gas should enhance the driven force in the bulk gas and hence the absorption performance. A novel concept known as Shift to Low Temperature configuration has been developed in order to strengthen the potentialities of partial oxy-combustion. This novel configuration aims at relaxing the operating conditions in the stripper based on the benefits – kinetics and driven force – observed in the absorption unit by means of shifting the operational CO2 cyclic capacity of the solvents towards lower energy requirements for solvent regeneration. In this work, three partial oxy-combustion operating conditions were tested in an experimental bench-scale CO2 capture facility. Results from the test campaign were further compared with both post-combustion and partial oxy-combustion at conventional operating conditions. The energy requirements were further improved as this novel configuration was applied, particularly using 118 °C as stripping temperature in combination with 60%v/v CO2 in the flue gas. Under these operating conditions, the energy penalty was reduced by 11% with respect to conventional partial oxy-combustion operation using the same flue gas composition – from 4.55 to 4.05 GJ/t CO2 using MEA 30 wt% as solvent. The energy penalty was further decreased by up to 64% in comparison with the post-combustion test. The results endorse the use of large CO2 cyclic capacity solvents to enhance the potentialities of the Shift to Low Temperature configuration for carbon capture applications.