Carbon Capture Technology

Post Combustion

 

 

Post combustion technology involves capturing the carbon dioxide from the flue gas of fossil fuel fired power facilities. Separation is made difficult by the low carbon dioxide partial pressure, meaning that chemical absorption using amines is currently the most viable option but other options including chilled ammonia, amino acids, membranes and adsorption are also under consideration.

 

Pre Combustion

 

Pre combustion technology involves either coal or biomass gasification or natural gas reforming to produce synthesis gas. The synthesis gas is then passed through shift reactors to maximise the hydrogen yield. The carbon dioxide is then captured from the synthesis gas by absorption. Sulphur removal occurs at a different point in the process depending on the fuel involved.

 

Oxy Fuel

 

Oxyfuel uses pure oxygen instead of air in a combustion chamber recycling a portion of the flue gas and producing a concentrated carbon dioxide product.  Purification of the flue gas is then employed, to remove nitrogen, oxygen, and argon, for transportation. The main energy consumers are the air separation unit, required for the oxygen supply, and the purification unit.

 

Industry Offgas


Industrial off-gas is produced from many industrial processes such as iron, steel and cement production. The carbon dioxide from such processes can be captured in a variety of ways depending on the composition, carbon dioxide concentration and pressure of the off-gas. New technologies are developing for steel production with CCS including top gas recycling, advanced direct reduction, ISARNA and alkaline hydrolysis. These technologies reduce the energy consumption compared to a conventional blast furnace and produce a carbon dioxide stream that can be treated and sequestered.

Costain Capability

Costain has considerable experience in carbon dioxide capture using a variety of different methods and technologies that have been selected and tailored for each application. Our knowledge of the different routes to capture and experience in large scale gas compression, treating, liquefaction and underground gas storage puts us in a position to be an overall project integrator delivering a complete solution from source to sink.

 

Pre Combustion and Post Combustion

 

Costain has considerable experience of working with licensors for the selection of optimal amine processing systems at high and low pressure, particularly for examples where gas composition is variable or where trace impurities can significantly affect operation. We have worked with almost all of the major amine licensors on a large number of amine systems for plants around the world.

 

Oxyfuel and Transport

 

Costain has designed and built many carbon dioxide purification and liquefaction plants using cryogenic fractionation technology and has process technologies that use semi-permeable membranes applied with fractionation. Associated with this, thermodynamic simulation techniques have been developed for pure carbon dioxide handling at low temperatures.

 

Oxyfuel and Pre Combustion

 

Costain has a strong capability in cryogenic air separation, synthesis gas separation, hydrogen processing and hydrogen purification. We are experienced in the modular design of coldboxes for these and some of the largest nitrogen rejection units in the world.

 

Costain has experience of hydrogen sulphide and mercaptan removal by chemical and physical absorption, adsorption, and further processing using the latest technology.