Sodium carbonate-based post combustion carbon capture utilising trona as main sorbent feed stock

In the pursuit of shifting technology towards sustainable, environmentally benign processes, post-combustion carbon capture technology is recognised to be a timely mitigation option. This paper presents the development of a novel sodium carbonate-based post combustion carbon capture process utilising the carbonate mineral trona (trisodium hydrogendicarbonate dihydrate) as main sorbent feedstock source. The energy penalty, the fraction of energy sacrificed to capture CO2 relative to the net energy produced serves as main performance indicator. Investigations on the correlative relationship between energy penalty as a function of capture efficiency are carried out by retrofitting the process to a 600 MW reference coal-fired power plant. The energy penalty of the global system features a distinct local minimum of 3.99%, corresponding to a CO2 capture efficiency of 90.00% and a CO2 outlet purity of 99.90%. The Specific Primary Energy Consumption for CO2 Avoided (SPECCA) index corresponding to this minimum is evaluated to be SPECCA = 0.514 MJ kg CO2-1. Sensitivity analyses on the effect of increasingly high flue gas volume fractions y(SO2) show that the capture efficiency is virtually unimpaired for calcination temperatures of 190 <= T <= 280 degrees C and y(SO2) ranging from 0.50 to 0.70%. Whilst commercially available CO2 capture technology is energy intense and prone to sorbent degradation, the process developed retains high capture efficiencies of calcium oxide-based looping cycles at low operating temperatures and eliminates the predisposition of amine-based sorbents utilised in scrubbing capture schemes to deplete due to the presence of SO2 in the inlet flue gas stream. It can be concluded that sodium carbonate based post-combustion capture processes are a competitive alternative to existing CO2 capture technologies.