Allied - Gasification Unit
Gasification is a century old technology, which flourished quite well before and during the second world war. Gasification can be broadly defined as the thermochemical conversion of a usually solid or liquid carbon-based material into a combustible gaseous product. The technology disappeared soon after the second world war, when liquid fuel became easily available. The interests in the gasification technology has undergone many ups and downs in running century. Today, because of increased fuel prices and environmental concern, there is renewed interest in this century old technology. Gasification has become more modern and quite sophisticated technology.
The advantage of this technology is decentralized energy conversion system which operates economically even for small scale. A gas producer is a simple device consisting of usually cylindrical container with space for fuel, air inlet, gas exit and grate. It can be made of fire bricks, steel or concrete and oil barrels. The design of gasifier depends upon type of fuel used and whether gasifier is portable or stationary. Gasifier alone itself is of little use. The complete gasification system consists of gasification unit (gasifier), purification unit and energy converter - burners or internal combustion engine.
Everywhere in the world, significant concern exists over relatively high cost of electricity for citizens and businesses, which imposes a financial burden and impairs country’s ability to compete effectively. On the other hand, there is a significant cost of protecting our environment. New environmentally preferred technologies and strategies are needed to produce and deliver electricity at lower cost and decreased environmental impacts. The potential problem is further compounded by a fact that systems reliability and the cost of electricity are adversely affected by large inventory of older steam power plants as well as old, outdated means of Management of Renewables (Waste).
Moreover, it is further amplified by a need for new cost-effective pollution control technologies needed to reduce the health and environmental impacts from power plant, landfills, and outdated Waste Remediation technologies. Therefore, a pressing need exists to develop superior, but economical method to produce electricity while reducing the waste landfills with the state-of-the-art control emissions of fine particles and vapor-phase aerosols/toxics.
An attractive and practicable possibility of renewables (waste) utilization for energy production is gasification integrated with a combined cycle. This technology offers the possibility to reach high efficiencies based on a fundamentally clean and renewable fuel. Integrated Biomass Gasification Combined Cycle (IBGCC) systems developed to replace the traditional combustor with a gasifier and gas turbine (White Paper, Requires ACROBAT Reader). Exhaust heat from the gas turbine is used to produce steam for a conventional steam turbine. The gas and steam turbines operate together as a combined cycle. Biomass gasifiers have the potential to be up to twice as efficient as using conventional boilers to generate electricity. For even greater efficiency, heat from the gas turbine exhaust can be used to generate additional electricity with a steam cycle. These improvements in efficiency can make environmentally clean biomass energy available at costs more competitive with fossil fuels.
Biomass gasification is a process that converts wood and/or green waste into a synthetic gas composed mainly of carbon monoxide and hydrogen. Gasification is basically a thermo-chemical process which converts biomass materials into gaseous component. The results of gasification is the producer gas, containing carbon monoxide, hydrogen, methane and some other inert gases. Mixed with air, the producer gas can be used in gasoline or diesel engine with little modifications.
Theoretically, almost all kinds of biomass with moisture content of 5-30% can be gasified, however, not every biomass fuel can lead to the successful gasification. Most of the development work is carried out with common fuels such as coal, charcoal and wood. It was recognized that fuel properties such as surface, size, shape as well as moisture content, volatile matter and carbon content influence gasification.
The key to a successful design of gasifier is to understand the properties and thermal behavior of the fuel as fed to the gasifier. Operation of a conventional gasification system demands knowledgeable and skilled operator. Those interested in this technology must remember that it requires hard work and tolerance. Compared to conventional system such as liquid fuel run engines, biomass gasification technology is inconvenient. But it is economical at many places and may lead to self-reliance in the crucial time of fuel crisis.