Low emissions coal technology

Several technologies are being developed and demonstrated to achieve CCS. Often these technologies are well established however not on the scale required for the mass production of coal fired electricity. New technologies can be broken down into a few areas; combustion, air separation and gas scrubbing. Terms such as low emissions and zero emissions are slightly misleading, these technologies do not eliminate GHG production. For these technologies to be considered clean the emissions must be physically captured and either stored or converted to a less damaging substance.

=Combustion technologies=

Presently the vast majority of electricity production is based on PF combustion of coal. There are two avenues for CCS; the first focuses on Retrofitting existing power plants and the second focuses on Power plants designed specifically for CCS.

=Air separation technologies=

Technologies in this category are designed to separate air into its constiuent gases. Air is made of Nitrogen (80%) and Oxygen (20%), when attempting to sequester exhaust gases from the combustion of air there is a large quantity of nitrogen which must be disposed of also. It is beneficial for input gases to be separated and coal burnt in a pure oxygen environment meaning that exhgaust gases are pure CO2 and less resources used in the disposal of CO2

=Gas scrubbing technologies=

There are several existing technologies already in use for cleaning exhaust gases from power plants. There are several technologies widely used for cleaning of NOX, SOXX and particulates. Some technogies exist for cleaning of CO2 from exhaust gases, these technologies are quite old (1960's) and have niche uses, such as for the food and fertillizer industries, they are too expensive for mass production of coal.

Many novel technologies are being developed to address the requirements of CCS, these can be divided into two areas, pre-combustion and post-combustion. Using gasified coal it may be possible to decarbonise the combustable gases prior to combustion, however in PF plants the only option is to clean exhaust gases.

=See Also=
 * Carbon Capture and Storage
 * Greenhouse gases
 * CCS Demonstration Projects