Post-Combustion CaptureShidongkou PCC Plant in China

 

Post-combustion capture (PCC) removes CO2 from the flue gas after the fossil fuel has been burned.

 

Power applications: Post-combustion technology can be used on natural gas combiined cycle units and bio-mass fired boilers.


Industrial applications: Post-combustion technology can be used on iron and steel plants using blast furnace capture, refining plants using process heater and combined heat and power (CHP) capture, chemicals using process heater, CHP, steam cracker capture, cement kilns using rotary kilns and pulp and paper plants using process heater and CHP capture.

Shidongkou PCC Power Plant, outside of Shanghai, China

 

More than 95% of the coal-fired plants in the world use coal combustion technology . About one-third of this capacity worldwide is less than 10 years old.  Installing PCC on these plants is essential to avoiding the worst impacts of climate change.


 

The Process

Post-combustion capture uses a chemical solvent to remove CO2 from the exhaust gas of a traditional power plants (gas or coal) or industrial facilities such as cement kilns, iron and steel production or in some refinery settings .  The solvent-- typically an amine solution-- binds with the CO2. The solvent-CO2 combination is separated from the rest of the exhaust gas and heated. The heat drives off relatively pure CO2 which is ready for compression and sequestration. The solvent is cooled and reused.

 

Diagram of the post-combustion process

 

Many companies offer variations on this basic approach. New technologies using selective membranes and solid materials instead of liquid solvents are under development.  Chapter three of the report "Coal Without Carbon" (.pdf) >> details current and emerging technologies. These alternatives hold promise of significant performance improvements over current technology, but also require significant development work prior to commercialization.

 

 

Natural Gas

Natural gas with carbon capture  uses post-combustion capture technology on natural gas power plants.  For the world to meet mid-century near zero carbon emissions, CCS will need to be installed not just on coal, but natural gas too.  Natural gas is expected to be abundant in the US due to recently developed shale gas fields.  Gas will increasingly displace some coal.  But even if all coal plants were replaced with natural gas, the reduction in CO2 would be about 50%.  Therefore CCS on gas is important.

 

Natural gas can be an advantageous fuel for power generation with CCS for several reasons:

  • Natural gas combined cycle combustion turbines capital costs roughly one third those of conventional coal power plants.
  •  NGCC produce roughly 60% less CO2 than conventional coal for an equivalent amount of electricity generated, CCS results in considerably less CO2 to capture, compress, and sequester with gas. 
  • Natural gas appears to be quite a promising fuel for advanced technologies like solid oxide fuel cells (“SOFC”), which may be able to both operate at extremely high efficiency and inherently separate CO2 from other exhaust gases.   Utilizing coal in a fuel cell is a much more daunting technological prospect (though there are companies making the attempt).

 

 

 

 



Fact

CATF is working to

  • Establish carbon capture and storage as a major global industry.
  • Create a new generation of technologies and institutions capable of removing carbon dioxide that has already been released to the atmosphere.
  • Work directly with industry on getting more federal and state money to support these projects. 
  • Communicate with national and international news outlets, seeking to be seen as an honest arbitrator in coal and climate factual disagreements