Gasification: Cleaner Electricity
A New Technology that Generates Electricity Cleanly from Fossil Fuel
In the light of Climate Change Agreements and worries over Carbon Footprints, a new technology is being developed which generates cleaner electricity from coal.
One of the major problems facing mankind in the future is the production of electricity in a way that will produce less carbon dioxide and other polluting gases. Throughout the world lots of electricity is generated by power stations that burn fossil fuels like coal oil and natural gas (methane). Although renewable energy sources like wind turbines and hydroelectric power are being used, they are simply not capable of producing enough electricity for modern consumption, and that consumption will only increase.
Climate Change Agreements
Governments throughout the world have pledged to reduce their emissions of greenhouse gases, which include carbon dioxide, sulfur dioxide and methane, since the Kyoto agreement in 1997. This means that they have had to look seriously at the ways they produce electricity from fossil fuels, one of the major sources of carbon dioxide.
Old Coal Technologies
One of the new technologies which have been developed in the light of these issues is gasification, a completely new way of burning fuels. Traditionally coal, the “dirtiest” of the fossil fuels, is crushed into powder and burned in air to produce heat. The heat boils water to produce steam which drives electric turbines. When coal is burned in air the carbon reacts with oxygen to form carbon dioxide. Sulphur is also present in coal and this burns to produce sulphur dioxide which is a major factor in acid rain.
Syn Gas
Gasification uses chemistry to change the way the coal produces heat. Instead of burning the coal, a gasifier is used which heats the coal dust under pressure with a limited amount of oxygen. Instead of burning, the constituents of coal react to form syn gas, which is primarily hydrogen and carbon monoxide. Other minerals in the coal, instead of escaping as particulates in the smoke, are collected at the bottom of the gasifier as a glassy substance. Sulfur forms compounds which can be converted to sulfur or sulfuric acid, which are useful to industry.
Combustion and Steam
Syn gas can be used to generate electricity very efficiently in two stages, first it is burnt in a combustion turbine and then the heat produced can be used to generate steam to power a steam turbine. It can also be used in the chemicals industry and for new types of fuel cells based on hydrogen.
There is still a large quantity of coal available in the world. In order to use this important resource without compromising the planet any more than it is already new technologies such as gasification are vital.
References:
http://www.guardian.co.uk/environment/2005/feb/16/environment.climatechange
http://www.fossil.energy.gov/programs/powersystems/gasification/howgasificationworks.html
