Partial oxy-combustion technology for energy efficient CO2 capture process

Highlights: • Partial oxy-combustion capture was tested in a bench-scale CO₂ capture unit. • The novel configuration achieved a 64% energy reduction respect to post-combustion. • The reboiler duty was reduced up to 11% of compared to conventional configuration. • The use of high cyclic capacity solvents can lead to further energy reductions. -- 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.