GASIFICATION

GASIFICATION

ABSTRACT:

Coal is the end product of a natural process of decomposition of vegetable matter buried in swamps and out of contact with oxygen for thousands of years. There are two main difficulties in use of coal. As a solid, it's difficult to transport compared to liquids and gas, and fundamentally it is difficult to remove contaminants from a solid. Major part of the countries in the world has coal reservoir as main source of the energy. Around 35% of total energy is obtained by coal in world. Present use of coal is inefficient and polluting. When coal is directly combusted, it generates harmful emissions like SOX and NOX. Methods used to control above emissions like flue gas desulfurisation, etc. are costly. Coal when directly combusted gives low calorific value, delayed combustion. The pulverized coal used produces a large amount of fly ash, which is mainly responsible for causing erosion of, pulverizes, boiler tubes and I.D. (induced draft) fans.

Thus there are several other parameters, which are deteriorating performance of power plant and there is a need for power generation technology, which can use high ash coals with more efficiency and least pollution. Thus coal gasification will be the right way compared to direct combustion to achieve above objectives in which we can obtain higher efficiency and less pollution.

Hence there is need for technologies for utilization of coals efficiently and cleanly, with abundantly available coals and prolonging the reserves of all the fossil fuels for use of future generations. These requirements can be met through application of coal gasification technology. Once coal is gasified, we can pipe it wherever want and in the gas phase, it is much easier to separate and remove the environmental contaminants. Environmentally clean, affordable power is the goal of research and coal gasification is one of the technologies that will make a difference.

Present report describes principle of coal gasification along with Integrated Coal Gasification Combined Cycle. Further working of the gasification plant is explained. Also report includes ‘development of energy sector in India through coal gasification’. Application of coal gasification for fuel cell is also presented.

INTRODUCTION:

Around 35% of total energy is obtained by coal in world. Present use of coal is inefficient and polluting. Hence there is need for technologies for utilization of coals efficiently and cleanly, substitution of lesser reserves of oil and gas with abundantly available coals and prolonging the reserves of all the fossil fuels for use of future generations. These requirements can be met through application of coal gasification technology.

Rather than burning coal directly, coal gasification reacts coal with steam and controlled amounts of air or oxygen under high temperatures and pressures to produce a gaseous mixture, typically hydrogen and carbon monoxide. These hot, coal gases exiting the gasifier are used to power a gas turbine (in the same manner as natural gas). Hot exhaust from the gas turbine is then fed to a heat recovery steam generator (HRSG). The steam from the HRSG is then fed to a conventional steam turbine, producing a second source of power (just as in a combined cycle plant).

Coal gasification is not only used for power generation but also it can become source of synthetic oil, coal chemicals, natural gas substitution. Also it can be used for development of the fuel cell. Thus coal gasification become member of clean coal technology with other advantages.

This report gives principle and implementation of coal gasification with development of coal gasification for fuel cell. Report describes how coal gasification is beneficial to India & difficulties in its implementation.


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