Environmental control technology for atmospheric carbon dioxide

Abstract

The impact of fossil-fuel use in the United States on worldwide CO 2 emissions and the impact of increased coal utilization on CO 2 emission rates are assessed. The aspects of CO 2 control are discussed, as well as the available CO 2 control points (CO 2 removal sites). The primary factor affecting the practicability of a CO 2 control system is the energy required by the control system. Of the three potential CO 2 control points, removal from the stacks of fossil fuel power plants appears to require the least amount of energy. Estimates of the energy required to capture and recover CO 2 from coal-fired power plant stacks by various processes are presented. Although capture and recovery of CO 2 is an important consideration in the overall scheme of CO 2 control, disposal or reuse of recovered CO 2 may be the weakest link in the CO 2 control chain. Of the several options considered, deep ocean storage appears to be the most promising. Two control scenarios are evaluated, one based on the absorption of CO 2 contained in power plant flue gas by seawater; the other, based on absorption of CO 2 by monoethanolamine (MEA). Captured CO 2 is injected into the deep ocean in both cases. Our analyses indicate that capture and disposal by seawater is not feasible, whereas capture and disposal using MEA is a possibility. However, the economic penalties of CO 2 control are significant; for example, at a CO 2 removal efficiency of 50%, it is estimated that the power generation efficiency of a conventional coal-fired power plant would be reduced from 34% to about 25%. The cost of power generation would be expected to double. For 90% CO 2 removal, power generation efficiency is reduced to between 15 and 6% and the cost of power generation increases by a factor of from 4 to 7. The use of non-fossil energy sources, such as nuclear or solar energy, to control the CO 2 emissions resulting from fossil energy usage is not considered in this study.