Research On CO₂ Adsorption And Transportation Technology

The frequent occurrence of extreme weather events and the greenhouse effect caused by large emissions of CO2 have seriously affected the global economic and environmental sustainability. Among all the CO2 capture technologies, adsorption method has the advantages of water-free, simple and flexible operation, low investment and low operating costs, and long adsorbent lifetime. CO2 transportation is a stage of CCS that links source and storage sites and plays an important role. This dissertation is funded by Cooperation Action within CCS China-EU (COACH) project, in which CO2 adsorption technology and adsorbents have been studied, and CO2 transportation technology and costs have been analyzed.Firstly, commercial carbon-based adsorbents and zeolites were characterized by low-temperature physical adsorption technique, and surface area, pore volume, size distribution and micropore volume were evaluated. Thermal analysis technique was used in adsorbent adsorption and desorption characteristics study with different adsorbents (AC1, AC2, CMS and Z13X) in different temperature condition (including 25℃,50℃,75℃) or CO2 concentration (pure and 15vol.%). Analysis shows, as the adsorption temperature raises, the adsorbents'CO2 adsorption capacity reduces significantly, and adsorbent performance ranking is Z13X> AC2> AC1>CMS.Secondly, adsorption bed adsorption experiments have been done on a newly built single bed adsorption experimental system with commercial adsorbents. Testing gas using in adsorption experiments is simulated flue gas, and CO2 concentration is 12vol.% similar to the true coal-fired power plant flue gas CO2 concentration. Breakthrough curves have been drawn for adsorption bed breakthrough and saturation characteristics analysis. With the same adsorption pressure condition, when the sample gas flow rate is larger, the breakthrough time is shorter and the bed CO2 adsorption capacity is smaller. With the same sample gas flow rate, the breakthrough time is longer when under higher adsorption pressure. Meanwhile, the adsorbent temperature at different position of the bed varies during adsorption. Overall, Z13X packed adsorption bed has a better adsorption performance than AC 1 packed adsorption bed.Finally, research has been done on CO2 transportation technology and cost analysis. For pipeline transportation, the pipeline pressure and temperature parameters have been determined; Pipe diameter, wall thickness and transportation costs have been calculated referring to specific calculation models and standards; Economic booster station spacing has been found under different CO2 mass flow rate. For ship transportation, ship type and transport scheme have been determined; Costs have been calculated and cost sensitivity study on ship volume change has been discussed. For the railway tank transportation, costs were calculated referring to the rules of railway freight tariffs, Rail Transportation No.46 file,2005. Cost analysis on COACH program CO2 transportation case shows costs for pipeline, ship and railway tank transportation are 43.13 RMB/t,54.95 RMB/t and 92.82 RMB/t, respectively, showing pipeline transportation is economically competitive.