Natural gas purification by heat pump assisted MEA absorption process

Natural gas purification is a critical pretreatment process before it can be injected into the pipeline delivery grid. Generally, Acid impurities (i.e. CO2 and H2S) in natural gas can be removed by MEA (monoethanolamine) absorption process. However, excessive energy consumption is still the challenge for the current absorption processes. In this work, a novel heat-pump assisted absorption process is proposed. To recover the waste condensation heat in desorption stage, the vapor distillate stream is compressed to elevate the exergy rate, and then coupled with the bottom stream. Meanwhile, the waste pressure of distillate is recovered by an expander. The simulation results indicated that the net energy input of the proposed absorption process could be saved to 7.2 MW, which equaled to 17:5% of the conventional process. The energy consumption of impurity removal (set CO2 as reference) for the heat-pump assisted absorption process can be reduced to 1.78 MJ/kg CO2. (C) 2017 Elsevier Ltd. All rights reserved.