Friday, July 1, 2011

Gasification - Helping the Environment

Gasification is the method with a thermo-chemical type wherein carbon-rich materials like coal, biomass or petro coke which are changed into gas. This gas now contains hydrogen and a lesser carbon dioxide of carbon monoxide. It is high pressure, under oxygen depleted and high heat steam condition. This is commonly called as Syngas. Gasification process is not only a way for efficient extracting of energy but it can also help the waste disposal system by returning double benefits.

There are different designs of gasifier but it is still falls into three categories for the design of gasification reactor or gasifiers which are the moving bed, entrained flow, and fluidized bed. Moving bed is the type of gasifier wherein the dry carbon fuel is fed from the top part. It responds with oxygen and steam as they flow in different direction of the bed while the carbon fuel slowly drops to the vessel. The contaminants that are traced are scrubbed from the syngas. In entrained flow, the fuel can be fed either wet or dry to the gasifier. The course of reactants or the oxygen and steam is upward and uni-directional up until the syngas leave from the gasification reactor. Underneath the gasifier, you will see the molten slags. Fluidized bed is the type of gasifier wherein the reactants flow upwards while the fuel is being injected to it. The un-melted ash, which is dry, will be evacuated at the base of the gasification reactor.

Gasification procedure is an old technology which was mainly used in the mid-1800s to 1900s. Its main purpose is to have town gas which comes from coal to produce light and heat. Even the farmers in WW II that is in need of gasoline is doing the homemade gasification process by using wood and turn it into gas or liquid fuel for their equipment and tractors. With the energy catastrophe that happened in 1970s, America was prompted to maintain and support the gasification process. From this came the creation of the gasification electric generating plants and power plants that operate in different parts of the world.

Some of the advantages of gasification process includes high efficiency rate, near-zero emissions, feedstock flexibility, energy security and product flexibility. However, there are also the disadvantages of the gasification process. One of the disadvantages or Syngas needs to be cleaned and purified also there are complex multi-stage for the gasification process. Initial setup for gasification is also expensive which also adds up to the disadvantages of gasification and there should be an up-front processing of feedstock.

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