Searches of cost effective ways for amine absorption unit design in CO2 post-combustion capture process

• The absorption-desorption unit operating with 20% MEA is studied.
• The energy efficiency of HEN of absorption-desorption unit is examined.
• The temperature approach influence on heat and cost efficiency is discussed.
• The efficient plate heat exchangers for HEN of ADU are proposed.
• The PHEs application in ADU decreases the energy consumption by up to 24%.

There is an increasing interest in post-combustion CO2 capture related to climate change and further use of the captured CO2 in enhanced oil and gas recovery, as well as a feed to produce products such as methanol or dimethylether, the use in hot dry rock technologies, etc. The currently used post-combustion capture method based on MEA (monoethanolamine) absorption without stream split has significant steam consumption to regenerate the amine solution. In this work, the HEN ADU (Heat Exchanger Network of an Absorption Desorption Unit) is analysed using the Process Integration methodology. It is supplemented with the search of economically viable options of desorption column parameters by computer modelling and the use of compact PHEs (plate heat exchangers) with intensified heat transfer. Based on the presented case study, the variation of temperature approach inside the rich/lean heat exchanger is considered. Its influence on the heat consumption, the energy efficiency and the investment cost of the HEN ADU unit are discussed. The use of PHEs in HEN ADU allows with the same or even smaller purchased cost of heat exchangers to save up to 13% more energy as compare to HEN with conventional shell and tube heat exchangers.