Associated Press of Pakistan
ISLAMABAD: Unless Pakistan starts using coal directly as a substitute for gas consumption in the power plant and other industries, it may not be able to meet the growing demand of gas which has a major role in national economy.
“There is an acute gas shortage all over the country besides power and we have to use our indigenous coal reserves to overcome the shortage instead of importing gas at very higher rates.
The present international rate of natural gas is high and when the cost of transportation and distribution is added, it will cost higher than the present gas price in the country,” said an alternative energy expert.
Reading a paper here at a seminar on Challenges to Energy Sector, he said coal gasification and coal-to-liquid are some proven technologies available which can be successfully employed in Pakistan to reduce dependence on imported oil and natural gas. In addition to coal, there are many waste materials like cow dung, municipal solid waste, industrial waste, rice husk, wheat and rice straw and other composite materials which can be used to produce bio gas, and can used a substitute of natural gas for winter heating and CNG filling stations for vehicle fuels. If this waste-to-energy technology is adopted on a fast track basis, then the problem of gas shortage can be overcome within a few years.
Coal gasification offers one of the most versatile and cleanest ways to convert the energy content of coal into electricity, hydrogen, and other energy forms, he said and added rather than burning coal directly, gasification breaks down coal, or virtually any carbon-based feedstock, into its basic chemical constituents. In a modern gasifier, coal is typically exposed to hot steam and carefully controlled amounts of air or oxygen under high temperatures and pressures. Under these conditions, carbon molecules in coal break apart, setting into motion chemical reactions that typically produce a mixture of carbon monoxide, hydrogen and other gaseous compounds. Gasification, in fact, may be one of the best ways to produce clean-burning hydrogen for tomorrow’s automobiles and power-generating fuel cells. Hydrogen and other coal gases can also be used to fuel power-generating turbines or as chemical “building blocks” for a wide range of commercial products.
The pioneering coal gasification electric power plants are now operating commercially in the United States and in other nations, and many experts predict that coal gasification will be at the heart of future generations of clean coal technology plants for several decades into the future. A coal gasification power plant, however, typically gets dual duty from the gases it produces. First, the coal gases, cleaned of their impurities, are fired in a gas turbine, much like natural gas, to generate one source of electricity. The hot exhaust of the gas turbine is then used to generate steam for a more conventional steam turbine-generator. This dual source of electric power, called a “combined cycle,” converts much more of coal’s inherent energy value into useable electricity. The fuel efficiency of a coal gasification power plant can be boosted to 50 per cent or more.