Analysis of Cost Savings Based on CO2 Avoided Cost Analysis

In this section, the CO₂ avoided cost at different ΔTmin of the lean/rich heat exchanger using the PHE and FTS-STHX are compared with that of the reference case (FTS-STHX with ΔTmin of 10 °C). The results are presented in Figure 15. Since the cost optimum ΔTmin of the FTS-STHX case in the standard capture process is 10 °C, no cost reduction is achieved at other ΔTmin. However, the cost reduction achieved by the two PHE cases and the lean vapour compression capture process with FTS-STHX is higher here (CO₂ avoided cost) compared to the CO₂ capture cost estimates. The optimum CO₂ avoided cost in the PHE cases achieved about 6% and 16.2% cost reduction in the standard and lean vapour compression CO₂ capture processes, respectively. The lean vapour compression case with FTS-STHX CO₂ avoided cost optimum achieved 12% cost reduction, compared to a 7.7% reduction in ordinary capture cost. This is due to the reduction in the amount of steam consumption when emissions reduction is considered. These cost reductions also indicate that the ΔTmin of the lean/rich heat exchanger is an important process parameter to optimise [11].