Environmental control technology for atmospheric carbon dioxide. Final report

Abstract

The impact of fossil fuel use in the United States on worldwide CO/sub 2/ emissions and the impact of increased coal utilization on CO/sub 2/ emission rates are assessed. The aspects of CO/sub 2/ control are discussed as well as the available CO/sub 2/ control points (CO/sub 2/ removal sites). The primary factor affecting the practicability of a CO/sub 2/ control system is the energy required by the control system. Of the three potential CO/sub 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/sub 2/ from coal-fired power plant stacks by various processes are presented. Although capture and recovery of CO/sub 2/ is an important consideration in the overall scheme of CO/sub 2/ control, disposal or reuse of recovered CO/sub 2/ may be the weakest link in the CO/sub 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/sub 2/ contained in power plant flue gas by seawater; the other, based on absorption of CO/sup 2/ by monoethanolamine (MEA). Captured CO/sub 2/ is injected into the deep ocean in both cases. 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/sub 2/ control are significant; for example, at a CO/sub 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/sub 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.