Gasification of Biomass

Solid biomass can be converted into a gaseous form. The gas can then run through a combined-cycle gas turbine or another power conversion technology such as a coal power plant. Many experts hope that gasification can yield more efficient biomass power plants. Biomass gasification is the latest generation of biomass energy conversion processes and is being used at a scale of up to 50 MW to improve the efficiency, and to reduce the investment costs of biomass electricity generation through the use of gas turbine technology. High efficiencies (up to about 50%) are achievable using combined-cycle gas turbine systems, where waste heat from the gas turbine is recovered to produce steam for use in a steam turbine. Economic studies show that biomass gasification plants can be as economical as conventional coal-fired plants. However gas cleanup to an acceptable standard remains the major challenge yet to be overcome.

New technologies are being developed to produce biogas for bio generation. Biogas consists of methane, which is found in natural gas, together with hydrogen and other gases and lessons are being learned from coal gasification systems. Some new gasification technologies make biogas by heating wood chips or other biomass in an oxygen-starved environment. Gasification is probably the most important and efficient energy-conversion technology for a wide variety of biomass fuels. The large-scale deployment of efficient technology along with interventions to enhance the sustainable supply of biomass fuels can transform the energy supply situation in rural areas. It has the potential to become the growth engine for rural development in the country.

A second method for making biogas is with landfills. As paper and other biomass decay inside a landfill, they naturally produce methane, which can be recovered by drilling wells into the landfill and piping the gas to a central processing facility for filtering and cleaning. Clean landfill gas is then ready to fuel a biopower plant or help to heat a building.

Biogas can be burned or co-fired in a boiler to produce steam for electricity generation. Biogas can also fuel gas turbines or combined-cycle generation systems. In a combined-cycle system, pressurised gas first turns a gas turbine to generate electricity. The waste gas from the gas turbine is then burned to make steam for additional power production.

Conversion of solid biomass into combustible gas has the advantages associated with using gaseous and liquid fuels such as clean combustion, compact burning equipment, high thermal efficiency, which can reach 60%-70%. In locations, where biomass is already available at reasonable low prices (e.g. rice mills) or in industries using fuel wood, gasifier systems offer definite economic advantages. Biomass gasification technology is also environment-friendly, because of the firewood savings and reduction in CO₂ emissions. Biomass gasification technology has the potential to replace diesel and other petroleum products in several applications.