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DOE Pulse
  • Number 416  |
  • June 23, 2014

Novel CO2 capture process patented

process-flow-diagram

Process-flow-diagram.

U.S. Patent # 8,617,499 was issued to scientists at DOE's National Energy Technology Laboratory for a CO2 capture process that minimizes steam required for regeneration while enhancing the water-gas shift reaction to produce H2 from synthesis gas from precombustion gas streams.

The water-gas shift (WGS) reaction is a chemical reaction in which carbon monoxide (CO) reacts with water vapor (H2O) to form carbon dioxide (CO2) and hydrogen (H2). The water-gas shift reaction is a highly significant industrial reaction and is used in conjunction with reforming of methane and other hydrocarbons for the production of high purity hydrogen, among other applications.

“Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal” describes a process for CO2 separation at warm gas temperatures (150-250 °C) from high pressure (> 380 psi) gas streams such as coal gasification gas streams using magnesium hydroxide known as Mg(OH)2. A Mg(OH)2 sorbent is used prior to the water-gas shift reactor to remove carbon dioxide and provide steam generated during CO2 removal for the water-gas shift reaction. The Mg(OH)2 sorbent is also used after the water-gas shift reactor to remove the remaining CO2 formed in the water-gas shift reactor to produce pure H2. This novel process contributes to a significant increase in overall power plant efficiency due to enhancement of the water-gas shift reactor performance.

[Linda Morton, 304.285.4543,
Linda.morton@netl.doe.gov]