Techno-economical evaluation and comparison of various CO₂ transportation pathways

Carbon Capture and Storage (CCS) is regarded as one of the most promising solutions for reducing emissions of greenhouse gases. Following capture, the CO₂ must be transported to the designated storage site. This transportation process can be achieved via various means, such as trucks/trains, or ships. Considerable research has focused on optimizing CO₂ transportation, particularly on converting CO₂ from a gas to a liquid to reduce volume and transportation costs. After thorough evaluation, it has been determined that acquiring CO₂ at 7 bar and -49 °C, as well as at 15 bar and -28 °C, represents the most efficient and cost-effective options for truck/train and ship transportation. To transport CO₂ in liquid state, liquefaction is a critical step in the pathway. In this paper, three different liquefaction systems including internal refrigeration (open liquefaction), external refrigeration (closed liquefaction) and precooled Linde Hampson process (open liquefaction) were studied. Each process was simulated in Aspen HYSYS, and optimized with a particle swarm optimization (PSO) algorithm in MATLAB to minimize the energy consumption. Afterwards, cost analysis was conducted to compare the liquefaction processes in terms of levelized cost. This study found that precooled Linde Hampson liquefaction process is the most cost-effective for the 7 bar scenario, with a cost of 19.18 $/tCO₂ liquified. On the other hand, it was found that the lowest levelized cost is given by external liquefaction with the use of ammonia as refrigerant for 15 bar case, with a levelized cost of 17.54 $/tCO₂ liquified.