WASTE TYPES MUNICIPAL SOLID WASTE

PYROLYSIS & GASIFICATION

      It is a process that converts carbonaceous materials, such as biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen The resulting gas mixture is called synthesis gas or syngas and is itself a fuel. Gasification is a method for extracting energy from different types of organic materials. The advantage of gasification is that using the syngas is more efficient than direct combustion of the original fuel; as it may be burned directly in internal combustion engines, used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process
Into synthetic fuel. Gasification can also begin with materials that are not otherwise useful fuels, such as biomass or organic waste. In addition, the high-temperature combustion refines out corrosive ash elements such as chloride and potassium, allowing clean gas production from otherwise problematic fuels. Thus, it is an important technology for renewable energy. In particular biomass gasification is carbon neutral. Gasification relies on chemical processes at elevated temperatures >700°C, which distinguishes it from biological processes such as anaerobic digestion that produce biogas. In essence, a limited amount of oxygen or air is introduced into the reactor to allow some of the organic material to be "burned" to produce carbon monoxide and energy, which drives a second reaction that converts further organic material to hydrogen and additional carbon dioxide. Several gasification processes for thermal treatment of waste are under development as an alternative to incineration. A major challenge for waste gasification Waste_Portal2/Technologies is to reach an acceptable (positive) gross electric efficiency. The high efficiency of converting syngas to electric power is counteracted by significant power consumption in the waste preprocessing, production of large amounts of pure oxygen (which is often used as gasification agent), and gas cleaning. Another challenge in real life is to obtain long service intervals in the plants, so that it is not necessary to close down the plant every few months for cleaning the reactor. Several waste gasification processes have been proposed, but few have yet been built and tested, and only a handful have been implemented as plants processing real waste. Four types of gasifier are currently available for commercial use: counter-current fixed bed; co-current fixed bed, fluidized bed and entrained flow.

 

Link for pyrolysis and gasification

 

 

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National Solid Waste Association of India (NSWAI) is the only leading professional non-profit organisation in the fields of Solid Waste Management of India.