Process of Gasification

Process of Gasification

	Process of Gasification The MSW that is received is sorted to remove the non-combustible materials. The remaining organic fraction (ROF) is shredded to achieve the feedstock size of less than 5 cm. The moisture content of feed is maintained at less than 20% to maximise the heat recovery. Densification of ROF is not required, and this saves significant capital expenses and operating costs. The ROF is fed into the feed hopper with an agitator and hydraulically driven feed auger.
The feedstock then passes to the main thermal reactor where at high temperature (900-1200°C) the ROF is converted into gas. Ash is removed from the base of reactor in a closed system. There are no fugitive airborne emissions from the ash systems. The gas flows from the top of the reactor vessel through pipes equipped with internal cleaners to mechanical gas cleaner vessel. Then the gas is passed through a series of mechanical cleaners to remove char, particulate matter, and any unreacted solids carried by the gas stream. The gas is then cooled through heat exchangers to the temperature as required by turbine, or boiler. A high voltage and low amperage electrostatic precipitator completes the gas cleaning and cooling process. A self-contained oil, tar or water separation system receives condensate from the electrostatic precipitator. Oils and tars are separated and re-injected into the reactor. The waste heat recovered from the reactor is used to preheat the feed-stock and reduce moisture to an acceptable limit (Solar Energy Research Institute, 1979).
The quality of gas is regularly monitored through a gas meter. As per the requirement, the gas is fed to IC engines to produce power. The engine emissions are usually quite low. Another option is to use the gas in gas-fired boilers for steam generation, which in turn produces power through steam turbines.

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