467083 Heat Integration of Absorption-Based Carbon Capture Processes in the Industrial Sector
The study then continues with a heat integration case study of an oil refinery situated on the west coast of Sweden, emitting 1.8 Mt CO2/yr from the four main chimneys. Over 100 coolers, using air or water as a cooling medium, are present at the refinery, providing cooling in the proximity of 500 MW. Because a system where over 100 new units are installed would be very complex and expensive, the possibility of installing fewer heat exchangers while having an acceptable loss of the available excess heat was investigated. Both the MEA and the ammonia process were evaluated based upon the levels of heat that resulted from this investigation.
The results point at a maximum heat recovery temperature of 108 °C for ammonia, and for MEA there is a boundary solution at the lower boundary of the investigated temperature interval, 90 °C. MEA could capture more CO2 than ammonia using only excess heat, and techno-economic calculations were then made for the implementation of the MEA process in the oil refinery, including the cost for excess heat collection. The calculations comprise of the cost of the MEA process at both boundary temperatures in the stripper-reboiler, 90 °C and (standard) 120 °C, at two different sizes, and CO2 concentrations. Compared to estimates where excess heat is not considered, the cost for carbon capture was decreased by up to 40 %.