Simulation of Loading Capacity of MDEA and DEA for Amine-Based CO2 Removal Using Hysys

摘要

Besides meeting international stringent LNG product specification, this work will address the problem of off-spec product, high operational cost of acid gas (CO2) removal and pollution-free product, which is currently a huge global challenge. This work studied other ways by which amine unit can best be optimized to produce LNG gas with low CO2-content and high cost of acid gas removal. MDEA instead of DEA solvent-absorption method was chosen for the optimization using HYSYS 3.1 process simulator to predict the CO2 removal through the establishment of process operating conditions. A base case of amine-based CO2 removal process was used to create a steady-state and dynamic simulation using HYSYS 3.1 simulator. The differences between the values of acid gas loading capacity and CO2 content of the existing DEA operational value and HYSYS simulations were 0.00005 and 4.98 respectively. This established the advantage and accuracy of the HYSYS simulator and the developed models. The simulation results showed that the proposed MDEA had higher CO2 removal capacity of 89% to 55.02% for DEA and lower CO2 content of 0.0012 mole of CO2 in sweet gas to 0.014 mole of CO2 in DEA. MDEA had higher solvent recovery of 83% to 60% recovery for DEA. The pump size required to recycle MDEA with molar flow rate of 1877 Kg mol/hr. was smaller and less expensive than that required for DEA at 2371 Kg mol./hr. resulting in lower production cost.