Flue-Gas Treatment From The Combustion of 1.9 million Tonnes/year Coal Containing High Sulphur, Nitrogen and Carbon Contents

Abstract

Flue gases produced by combustion of coal containing high Sulphur and nitrogen is processed and cleaned for its safe exit to the environment to reduce the adverse effects of SOx, NOx, and CO2. To do so, coal analysis of Thar (Pakistan) is done because of its high Sulphur and nitrogen content. Flue gases that leave the Combustion chamber are passed through the Selective Catalytic Reduction Reactor (SCR) where NOx reduction occurs with ammonia water and outlet of SCR goes through the heat exchangers to drop the temperature. Then it is Desulfurized in scrubber which uses lime slurry (CaCO3) for the removal of SOx. It also gives gypsum as a by-product which is by cement industry. CO2 is absorbed with Mono Ethanol Amine (MEA) in the absorber. Clean gas is set free to the environment from the top. By absorbing CO2 MEA becomes rich MEA, to make process economical rich MEA is regenerated which is done by using a stripper column. From which MEA is regenerated by boiling. CO2 from top of the column is delivered to storage and lean MEA is cooled down using a heat exchanger and cooler then sent back to the absorber.