Glossary of Terms - CO2

This glossary covers words, phrases, and acronyms that are commonly used in various processes for the CO2 capture and storage industry. Some words may have different meanings when used in other contexts.

Absorption: The taking up and holding of a liquid or gas by a substance (a solid or liquid) through pores or gaps between molecules. In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase - gas, liquid or solid material.

Absorber Column: A vessel containing trays or packing material that provides gas-liquid interfacial area for mass transfer operations.

Adsorption: Taking up and holding (a gas, liquid, or dissolved substance) in a thin layer of molecules on the surface of a solid substance. Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or a liquid (adsorbent), forming a film of molecules or atoms (the adsorbate).

Amine: Organic chemical compound containing one or more nitrogens in -NH2, -NH or -N groups. The post combustion carbon capture technology for separating CO2 from flue gases, or other gas streams, is scrubbing the CO2-laden gas stream using an amine in cyclic absorption then desorption process. In this process, within the absorber column, the amine absorbs the CO2 before being transferred to the amine regenerator/stripper column where CO2 is stripped from the amine by means of applying heat.

Capacity Factor: Capacity factor of a plant is the ratio of the actual output of a plant over a period of time and its output if it had operated at full capacity during the entire time of that period.

Capture: The removal of CO2 from fossil fuels either by pre- or post-combustion.

Capture Efficiency: The amount (as a fraction) of CO2 that is removed or separated from a CO2-laden gas stream.

Carbon Credit: A financial instrument that is transferable and saleable which provides an organization with a financial benefit from CO2 emission reductions.

Carbon Dioxide (CO2): A colorless, odorless gas that is produced when animals (including humans) breathe or when carbon-containing materials (including fossil fuels) are burned. Carbon dioxide is essential to the photosynthesis process that sustains plant and animal life, however, carbon dioxide can accumulate in the air and trap heat near the Earth's surface (the "greenhouse effect").

Carbon Footprint: A carbon footprint is "the total set of GHG (greenhouse gas) emissions caused directly and indirectly by an individual, organization, event or product" (UK Carbon Trust 2008). An individual, nation or organization's carbon footprint is measured by undertaking a GHG emissions assessment.

Carbon Trading: An approach that relies on public markets to allow producers with excess emissions to trade with those with reduced emissions. This ensures, with proper monitoring, that emissions levels stay within a regulated amount.

CCS: Carbon dioxide Capture and Storage.

Clean Coal: When CCS and other flue gas cleaning techniques are applied to coal fired power stations, the environmental emission is reduced significantly. This technology is termed as "clean coal" technology. The DOE defines clean coal as "a new generation of energy processes that sharply reduce air emissions and other pollutants from coal-burning power plants."

Clean Development Mechanism (CDM): A CDM allows a country with an emission-reduction or emission-limitation commitment under the Kyoto Protocol to implement an emission-reduction project in developing countries. Such projects can earn saleable certified emission reduction (CER) credits, each equivalent to one tonne of CO2, which can be counted towards meeting Kyoto targets.

Climate Change: Climate change is the variation in the average global or regional climate as measured by comparators such as average temperature and rainfall. The term has more recently been used commonly to describe the rising anthropogenic climate change.

CO2 Avoided: The discrepant amount between CO2 captured and stored, and the amount of CO2 which would have been produced without capture.

DCC: Direct Contact Cooler. A DCC may be required to reduce the temperature of a gas stream before entering the absorption column. Reducing CO2-laden gas stream temperatures can improve the solvent performance in a CO2 capture process.

DOE: The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety.

Emissions credit: A tradable financial commodity that gives its holder the right to emit a certain quantity of GHGs (q.v.).

Emissions Trading: A trading mechanism that provides permits for the release of a predetermined number of tons of a pollutant which can later be bought, sold or traded.

Energy Penalty: In terms related to a power plant, the energy penalty is the fraction of the fuel that must be dedicated to CCS activities for a given quantity of fuel input to the power generation plant.

EOR: Enhanced Oil Recovery; the recovery of oil from a reservoir using means other than natural reservoir pressure. Enhanced Oil Recovery generally results in the removal of increased amounts of oil from a reservoir when compared to employing methods using natural pressure or pumping alone.

FGD: Flue gas desulfurization is commonly known as FGD and is the technology used for removing sulfur dioxide (SO2) from the exhaust flue gases in power plants that burn coal or oil.

Flue Gas: Gases that are produced through the combustion of a fuel. These are gases normally emitted into the atmosphere.

Gasification: Process by which a solid fuel (generally containing carbon) is transformed into a fuel with carbon- and hydrogen-containing gases after reacting with air or oxygen and steam.

GHG: Greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydroflurocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6).

Greenhouse Effect: The Greenhouse Effect is attributable to the increasing consumption of fossil fuels, particularly oil and coal, that increases emissions of carbon dioxide (CO2). CO2 restricts the sun's heat from escaping from the atmosphere, thus giving rise to global warming.

GWP: Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. GWP is calculated relative to CO2 and it is always accompanied with time interval.

Hazardous Waste: By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed. Possesses at least one of four characteristics (ignitability, corrosivity, reactivity, or toxicity), or appears on special EPA lists.

HRSG: A heat recovery steam generator or HRSG is a heat exchanger that recovers heat from a hot gas stream. It produces steam that can be used in a process or used to drive a steam turbine.

HSS: Heat stable salts (HSS) are strong acid anions tied up with amine molecules to form a salt. HSS are thermally stable and cannot be regenerated by means of heat. The presence of HSS reduces the solvent capacity to carry acid gas (CO2) and are also corrosive.

ID Fan: Induced Draft fan. Is a fan or blower is required to overcome the pressure drop in flue gas conditioning and CO2 absorption columns.

IGCC: Integrated Gasification Combined Cycle. A generation method in which hydrocarbons or coal are gasified to be used as a fuel to drive gas and steam turbines.

Impurities: Substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound.

IPCC: Intergovernmental Panel on Climate Change. The IPCC is a scientific intergovernmental body set up by the World Meteorological Organization (WMO) and by the United Nations Environment Programme (UNEP).

Kyoto Protocol: Protocol to the United Nations Framework Convention on Climate Change - adopted at Kyoto, Japan in 1997.

Lean Amine: In the amine capture process, CO2 is absorbed by chemical solvent (amine) based on its reactivity and solubility in the amine. Amine loaded with CO2 at its maximum equilibrium capacity is termed as rich amine. When CO2 is stripped off from the rich amine in the amine regenerator, partially loaded amine is left at the bottom of the amine regenerator. Partially loaded amine is termed as lean amine which can be used for further CO2 removal.

Lean/Rich Heat Exchanger: A plate type or shell and tube type heat exchanger used in the amine-based CO2 capture process to recover the maximum amount of heat from hot lean amine, coming from the amine regenerator, and transferring this recovered heat to the rich amine going into the amine regenerator. Lean/rich heat exchangers are utilized to make the amine-based CO2 capture process energy efficient.

Membrane: A sheet or block of material that separates selectively fluid mixture components.

Mitigation: An anthropogenic intervention to reduce the anthropogenic forcing of the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks.

Off Gas: Off gas is the treated gas stream leaving the CO2 absorber from which a significant amount of CO2 is removed by absorption into the amine.

Oxy-fuel Combustion: This process involves burning fossil fuel in nearly pure oxygen rather than in air-producing a nitrogen free flue gas with water vapor and a high concentration of carbon dioxide as its main components. This also makes it easy to further concentrate the flue gas to an almost pure stream of CO2.

Post-combustion Capture: The capture of carbon dioxide after combustion.

Pre-combustion Capture: The capture of carbon dioxide following the processing of the fuel before combustion.

Reclaimer Sludge: Reclaimer sludge is the residual semi-solid material left from the solvent reclamation process. Solvent reclamation is required to maintain amine performance in large industrial-scale CO2 capture processes. During solvent reclamation, impurities such as heat stable salts (HSS) are removed from the amine in a reclaimer vessel by injecting caustic before the amine is re-introduced back into circulation. Reclaimer sludge is a viscous, semi-solid material formed at the bottom of the reclaimer vessel.

Amine Regenerator: An amine regenerator is a vessel containing trays or packing material that provides gas-liquid interfacial area for mass transfer operations. CO2 diffuses into the solvent within the absorber column and reacts with the amine to form a weak amine-CO2 bond. This weak bond can be broken by application of heat in the amine regenerator column and is called the amine regeneration process.

Re-fitting:refers to the replacement of current technology or equipment with improvements or updates in technology, capacity or performance. In the case of CO2 capture, re-fitting generally provides additional production capacity for the energy required to capture the CO2.

Retrofitting: Retrofitting refers to the addition of new technology or features to older systems.

Rich Amine: In the amine process, CO2 is absorbed by chemical solvent (amine) based on its reactivity and solubility in the amine. Amine loaded with CO2 at its maximum equilibrium capacity is termed as rich amine.

Scrubber: A gas-liquid contacting device for the purification of gases or capture of a gaseous component. Also termed as "absorber" depending on the importance of treated gas or absorbed gas.

Sequester: To store something so that it is no longer available. Carbon sequestration involves the removal or storage of carbon dioxide so that it can't be released into the atmosphere.

Solvent: A solution generally comprised of water and amine which is utilized to capture CO2 from a CO2 laden gas stream.

Stripper Column: A stripper column is an alternative industry name for the amine regenerator.

TKO™: Thermal Kinetics Optimization is a process configuration for amine-based CO2 capture that significantly reduces the amount of energy required to capture CO2. TKO™ is a development of the International Test Center for CO2 (ITC) in conjunction with University of Regina, Saskatchewan Canada.

Sources:

www.Wikipedia.org
www.co2captureproject.org