CO2 Capture from Flue Gas Using Membrane: Current Status and Remaining Problems

It is now generally accepted that global temperatures are rising and this rise is caused by the emission of CO₂ and other greenhouse gases to the atmosphere. Almost 40% of CO₂ emissions come from the use of fossil fuels in power plants and various industrial processes. Replacing the fossil fuels used in power generators with wind, solar and nuclear power is underway, but will take 30 to 50 years to complete, and some industrial processes such as cement production and steel production have no feasible way to avoid fossil fuel combustion.

A number of studies have shown that the way to handle this issue is to develop cost-effective technologies to capture the CO₂ produced in power plants and industrial processes and sequester it underground. Development of this CO₂ capture and sequestration (CCS) technology provides a bridge to help the world transition to a non-fossil fuel future.

The only current demonstrated CCS technology is amine absorption. Two full-scale amine CO₂ capture plants have been built and are in operation, but there is little enthusiasm to build more. The principle problem is the processes’ high cost. The use of membranes has emerged as the most promising second generation CCS technology. Membrane technology is at the development stage. Pilot plants have been built and the process is expected to have a lower cost than amine absorption, as well as offering significant operational advantages; simple flow scheme, much smaller footprint, no new emission issues, and no hazardous chemicals to handle and dispose; also the process is powered by electricity so that no changes to the power plant steam cycle are needed.

Most of the current U.S. work on membranes has been sponsored by the Department of Energy and has focused on CO₂ capture from coal power plants. However, it is possible that the first full-scale plant will be installed on industrial CO₂ sources, such as cement and steel plants.

It is now generally accepted that global temperatures are rising and this rise is caused by the emission of CO₂ and other greenhouse gases to the atmosphere. Almost 40% of CO₂ emissions come from the use of fossil fuels in power plants and various industrial processes. Replacing the fossil fuels used in power generators with wind, solar and nuclear power is underway, but will take 30 to 50 years to complete, and some industrial processes such as cement production and steel production have no feasible way to avoid fossil fuel combustion.

A number of studies have shown that the way to handle this issue is to develop cost-effective technologies to capture the CO₂ produced in power plants and industrial processes and sequester it underground. Development of this CO₂ capture and sequestration (CCS) technology provides a bridge to help the world transition to a non-fossil fuel future.

The only current demonstrated CCS technology is amine absorption. Two full-scale amine CO₂ capture plants have been built and are in operation, but there is little enthusiasm to build more. The principle problem is the processes’ high cost. The use of membranes has emerged as the most promising second generation CCS technology. Membrane technology is at the development stage. Pilot plants have been built and the process is expected to have a lower cost than amine absorption, as well as offering significant operational advantages; simple flow scheme, much smaller footprint, no new emission issues, and no hazardous chemicals to handle and dispose; also the process is powered by electricity so that no changes to the power plant steam cycle are needed.

Most of the current U.S. work on membranes has been sponsored by the Department of Energy and has focused on CO₂ capture from coal power plants. However, it is possible that the first full-scale plant will be installed on industrial CO₂ sources, such as cement and steel plants.

This is because the CO₂ concentration in flue gas from coal power plants is 13 to 15%, while the CO₂ concentration of flue gas from cement and steel plants is 20 to 30%. This higher concentration is beneficial for absorption processes, but is even more useful for membrane processes. In this paper, we will review the current states of membrane technology applied to CO₂ capture. The problems that remain to be solved will be discussed.