Coal gasified gas(CGG), also known as Coal gasification or Coal to gas, such as producer gas, water gas, and semi-water gas, etc., refers to the gases containing combustible components produced by desulfurization and purification of coal as raw material, with air (or oxygen) and steam as gasifying agent after gasification under pressure at high temperature in a furnace.
The gasifying agent of coal gasification is different and its composition is different. The main components of gas are CO (75%), H2 (6%), CH4 (3%), CO2 (9%), the rest are N2. After desulfurization, the main components of the gas are CO and H2, and the content of CH4 is generally less than 2%.
Coal gasification technology is one of the main ways to produce syngas products. Solid coal is converted into gaseous syngas through gasification process, meantime, by-products such as steam and ash are produced. In coal gasification, there must be three conditions: gasifier, gasifying agent and heat supply. Coal gasification technology can be divided into three categories: fixed bed gasification, circulating fluidized bed gasification and entrained-flow gasification technology. All kinds of gasification technology have their own advantages and disadvantages, and have certain requirements for the quality of raw coal. The advanced technology and maturity degree of technology are also different.
Coal gas is a kind of artificial gas - a combustible gas which is produced by crushing, pressure and pyrolysis of fuel coal. It is a combustion mode of clean coal utilization technology. The calorific value of coal gas is lower than that of natural gas, but its preparation is convenient. It can be produced by own equipment without restriction of transportation pipeline. At present, coal gas is an irreplaceable flammable gas in the utilization of clean energy in China at the status of unsufficient natural gas supply. Because of its many advantages, coal gas has been widely used in industrial and mining enterprises, and can be used for power generation and domestic gas.
Synthetic Natural Gas(SNG), refers to the synthetic gas which is produced by coal gasification and then methanation. Gasification is an effective way to produce oil substitute with high efficiency of energy conversion and mature technology.
With the continuous development and advancement of coal gasification and gas turbine technologies, large capacity, high efficiency and low emission will be the trends of IGCC technology.