Socolow 0506 Notes

Socolow, Scientific American 0506, “Can We Bury Global Warming?”

  1. Droplets of amines are sprayed into the exhaust gas stream after removing sulfur. In a separate stripper tower, the amine liquid is heated to release concentrated CO2, regenerating the chemical absorber.
  2. In a combined-cycle system, coal is first burned partially to produce syngas---pressurized hydrogen and CO. Sulfur is stripped, and then the syngas is burned to produce CO2 and water. To scrub the CO2, the syngas is converted into CO2 and hydrogen, the CO2 is scrubbed, and then the remaining hydrogen is burned in the gas turbine.
  3. Using pure oxygen rather than air eliminates the nitrogen from flue gases, making scrubbing easier. However, no materials are available that can withstand the higher temperatures. A possible approach is to combine exhaust gases with reactants to dilute the reaction and lower the gas temperature.
  4. Estimates the cost of capturing and storing a ton of CO2 at a coal gasification combined-cycle plant will be about $25. This would raise the cost of coal-generated electricity by about 2 cents/kWh (about 20%).
  5. Injected CO2 needs to go at least 800 m below the surface, where pressure is 80 atm, enough to make the CO2 supercritical.
  6. a 1-GW plant would produce about 100,000 barrels of CO2/day. Over a 60-year lifetime, the plant would need a 3 Gbbl reservoir. Only 500 such giant fields are known to exist.
  7. Injection of pressurized CO2 into old oil fields can enhance recovery by lowering crude oil’s interfacial tension. But doesn't this mean that the CO2 will come up again with the extracted crude?
  8. Carbon sequestration in oil and gas fields will most likely proceed side by side with storage in ordinary brine formations, because the latter structures are far more common. Geologists expect to find enough natural storage capacity to accommodate much of the carbon dioxide that could be captured from fossil fuels burned in the 21st century.