A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers. Carbon dioxide scrubbers are also used in controlled atmosphere (CA) storage. They have also been researched for carbon capture and storage as a means of combating global warming.
It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers.
The primary application for CO2 scrubbing is for removal of CO2 from the exhaust of coal- and gas-fired power plants. Virtually the only technology being seriously evaluated involves the use of various amines, e.g. monoethanolamine. Cold solutions of these organic compounds bind CO2, but the binding is reversed at higher temperatures:
- CO2 + 2 HOCH2CH2NH2 ↔ HOCH2CH2NH3+ + HOCH2CH2NHCO2−
As of 2009, this technology has only been lightly implemented because of capital costs of installing the facility and the operating costs of utilizing it.
While there are many prototypes of CO2 scrubbers, most use similar technology to remove carbon dioxide from the air. Although the technology to create the CO2 scrubber is advanced, the function of the machine is easy to follow.
- Air polluted with carbon dioxide is pumped into the CO2 scrubber.
- The air comes into contact with an ion exchange resin, which attracts the carbon dioxide molecules.
- The cleaned air is then pumped out of the CO2 scrubber.
The ion exchange resin must be cleaned periodically to retain its usefulness. Currently, humid air is used to remove the carbon from the scrubber. The carbon must then be discarded or reused. One possible use is to pump the collected carbon dioxide into a greenhouse to encourage quicker plant growth. Other scientists see potential in growing algae with the collected carbon, which could then be used as food or fertilizer.
- A CO2 scrubber can help protect the economy by diminishing the need to reduce the use of fossil fuels, which remain less expensive than renewable and alternative energy sources.
- Finding ways to reduce carbon in the atmosphere, some argue, is simply pragmatic, because most consumers and corporations are not willing to reject fossil fuel use.
- Using a CO2 scrubber will reduce the amount of greenhouse gases that lead to global warming.
- It is estimated that the amount of carbon in the atmosphere is nearly 40 percent higher than before the Industrial Revolution, so some environmentalists argue that scrubber technologies are needed regardless of advances in alternative energy sources.