ECONOMIC EVALUATION OF OXY-FUEL COMBUSTION TECHNOLOGY BASED ON EXISTING COAL-FIRED POWER PLANTS IN CHINA

摘要

As the increase of greenhouse gas emission, new technologies with lower CO2 emissions, whch can accommodate capture and sequestration of carbon dioxide, have been developed. For existing coal-fired power plants, a promising technology is O2/CO2 recycle (Oxy-fuel) combustion which combines a conventional combustion process and a cryogenic air separation process. There are no full-scale plants using oxy-fuel combustion in operation. This research evaluates the economic characters of oxy-fuel combustion plants retrofitted to existing conventional coal-fired plants. The electricity cost and the CO2 avoidance cost are considered as reference for evaluating Oxy-fuel combustion technology, and the CO2 tax is also discussed. Taking the CO2 selling into account, the electricity cost of the Oxy-fuel plant is nearly equal to that of the conventional plant. The CO2 avoidance costs of the retrofitted 2×300MW and 2×600MW Oxy-fuel plants are 274.9 ￥/t and 250.45 ￥/t, respectively. When the CO2 tax value equals to the CO2 avoidance cost, adding a CO2 capture unit to a conventional plant is economical, therefore, the CO2 emission can be mitigated. The results indicate that Oxy-fuel combustion is a cost-effective method of CO2 capture, and it is technically feasible with current technologies.