Evaluation of biogas upgrading technologies using a response surface methodology for process simulation

Biogas is commonly upgraded to biomethane to produce a better biofuel. The aim of this work is to compare different types of solvents in biogas upgrading while using an absorber-stripper process. A conventional single-loop absorber-stripper process configuration was simulated with ProMax® for three types of solvents: diglycolamine (DGA), dimethyl ethers of polyethylene glycol (DEPG) and water. Absorption temperature, absorption pressure, CO2 concentration, solvent circulation rate and steam rate (only for DGA) were considered as varying parameters. The effects of these parameters on energy consumption, CO2 capture and CH4 recovery were studied by applying response surface methodology (RSM) to the simulations of the processes. The comparison of the processes at the optimum operating conditions for RSM with the three solvents has shown that the process with water is the simplest and most robust of the three, obtaining high levels of CO2 capture and CH4 recovery with the lowest energy consumption.