Optimization of ship-based CCS

Abstract

This study developed an economic evaluation model for CCS (Carbon Capture and Storage) chain where pipelines and ships were expected to come into play in transporting CO2 from power plants to offshore storage sites. In case of ship-based transportation, several alternatives with various operating conditions were feasible, demanding optimization of the transportation mode. The ship-based CCS chain is consisted of six segments: compression system, pipeline, refrigeration system, storage tank, barge and CO2 carrier. Since there were several design alternatives in ship-based CCS chain with adjustable operating conditions, those options were suggested and evaluated for the optimization. Installation of one compressor or two was considered and fifteen refrigeration alternative processes were suggested. Four different sizes of the CO2 carrier were proposed to optimize the capacity of the CO2 carrier. The economic evaluation model was based on the LCC (Life Cycle Cost) methodology. The LCC was estimated for the design options with availability taken into account as well as the CAPEX (Capital Expenditure) and OPEX (Operation Expenditure). The CAPEX and OPEX were estimated after the design parameters were determined. The economic evaluation model was applied to the LCC estimation of two cases. The LCC results showed that the governing factor was OPEX, dominantly affected by the liquefaction system. The unavailability cost gave a significant impact on the estimated LCC so that the wrong conclusion could be drawn on the best method without considering the production availability. The results in the CO2 carrier demonstrated that the size of CO2 carrier should be defined after the economic evaluation because there was no effect of economies of scale.