Optimization of MDEA-PZ Ratio and Concentration for CO2 Removal in Semi-Lean Membrane Contactor Process

Membrane contactor has garnered interest in the recent decade due to its advantages. This study looks at optimisation of the amine concentration, comprising of methyldiethanolamine (MDEA) with piperazine (PZ) in membrane contactor to remove CO2 from 25mol% down to 6.5mol%. 37 experiments were carried out and the results were analysed through response surface analysis. Model is found to be significant with R2 of 0.9854. Based on contour plot produced, there exists a trade-off between amine concentration and viscosity that greatly impacts the performance. For better overall evaluation, the amine regeneration side is considered by running process simulation through gPROMS to obtain data on expected hydrocarbon co-absorption and amine regeneration energy required. The optimum amine is found to be at 45wt% concentration and MDEA-to-PZ ratio of 0.047 where the process would meet outlet spec whilst minimising amine regeneration duty and the amine rich loading.