Abstract
Current Carbon Capture and Storage (CCS) technologies focus on large, stationary sources that produce approximately 50% of global CO2 emissions. We propose an industrial technology that captures CO2 directly from ambient air to target the remaining emissions. First, a wet scrubbing technique absorbs CO2 into a sodium hydroxide solution. The resultant carbonate is transferred from sodium ions to calcium ions via causticization. The captured CO2 is released from the calcium carbonate through thermal calcination in a modified kiln. The energy consumption is calculated as 350 kJ/mol of CO2 captured. It is dominated by the thermal energy demand of the kiln and the mechanical power required for air movement. The low concentration of CO2 in air requires a throughput of 3 million cubic meters of air per ton of CO2 removed, which could result in significant water losses. Electricity consumption in the process results in CO2 emissions and the use of coal power would significantly reduce to net amount captured. The thermodynamic efficiency of this process is low but comparable to other “end of pipe” capture technologies. As another carbon mitigation technology, air capture could allow for the continued use of liquid hydrocarbon fuels in the transportation sector."
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First, Zeman refers to "large, stationary sources" of CO2 emissions, without specifying what those might be. Coal-fired power plants are the obvious targets, but it must be emphasized and repeated that they are not the only industrial point sources; with cement kilns, and various chemical and petroleum processors, being significant rivals. Moreover, as we've documented, natural point sources, such as volcanoes, and dispersed natural sources, wherever rotting vegetation might be accumulated, i.e., swamps, the Tundra in summer, etc., dwarf the emissions of coal utilization industry.
Second, he proposes a wet scrubbing system for ambient air processing that is likely archaic compared to other CO2 air capture proposals, such as Sandia National Laboratory's "Sunshine to Petrol" development, as we've documented, which proposes the use of, primarily, solar power both to capture CO2 from the atmosphere and to recycle it into more liquid hydrocarbon fuels.
Third, to emphasize the foregoing, Zeman envisions only fossil fuel-generated power as the energy source for his CO2 capture scenario, as in:
"Electricity consumption in the process results in CO2 emissions and the use of coal power would significantly reduce to (the?) net amount captured."
As we have documented from other sources, that is not the only way to go about it, and it is an extraordinarily narrow view.
The purpose of our citing Zeman in this report is: Air capture of Carbon Dioxide is technically feasible and potentially practical, as documented herein.
And, since the CO2 can be captured from the atmosphere, collection facilities can be located at dispersed sites where environmental, carbon-neutral energy, i.e., solar, wind, hydro, etc., can be harnessed to effect bothand it's subsequent conversion into commercially valuable hydrocarbon compounds. the capture of CO2 from the atmosphere
We don't have to burn more fossil fuel, and thereby generate more CO2, to accomplish the recycling of CO2.
And, Zeman does acknowledge that "air capture could allow for the continued use of liquid hydrocarbon fuels in the transportation sector".
"Liquid hydrocarbon fuels" which definitely could, and we assert should, be increasingly synthesized from Coal, and from recycled Carbon Dioxide.