Design And Fabrication Of Downdraft Gasifier Applied To I.C. Engine
Biomass gasification is basically the conversion of solid biofuels into a combustible gas mixture known as „syn-gas‟ or „producer gas.‟ A gasifier is a chemical reactor that performs this conversion
|Working Principle of an Imbert type Downdraft Gasifier|
Biomass resources are potentially the world‟s largest and most sustainable energy sources for power generation in the 21st century. The current availability of biomass in India is estimated about 500 million metric tonnes per year. Ministry of New and Renewable Energy has estimated surplus biomass availability at about 120 – 150 million metric tonnes per annum covering agricultural and forestry residues corresponding to a potential of about 17,000 MW. Gasification is a thermo-chemical process by which carbonaceous (hydrocarbon) materials (coal, petroleum coke, biomass, etc.) can be converted to a synthesis gas (syngas) or producer gas by means of partial oxidation with air, oxygen, and/or steam. The device which performs this work is known as gasifier. Gasifier is a chemical reactor where various complex chemical and physical processes take place. A hydrocarbon feedstock (biomass) is fed into a high-pressure, high-temperature chemical reactor (gasifier) containing steam and a limited amount of oxygen. As biomass flows through the reactor it gets dried, heated, pyrolysed, partially oxidized and reduced. Under these “reducing” conditions, the chemical bonds in the feedstock are severed by the extreme heat and pressure and producer gas is formed. The main constituents of producer gas are hydrogen (H2) and carbon monoxide (CO). A typical composition of syngas produced from wood gasification on volumetric basis is given below, Producer gas derived from biomass can be used in IC engine with some modifications. Spark ignition (SI) engine can be made to run entirely on producer gas and compression ignition (CI) engine replaces 60% - 80% fuel oil by using producer gas.
Experimentation and Analysis Once the complete assembly of the gasifier is finished, it would be operated using wood pellets as biomass and charcoal grate for initial starting. The gas generated would be tested to determine its composition, calorific value and most importantly tar content.
1. Drastic reduction in fuel consumption.
2. Low Tar content.
3. Easily implemented in small scale industries, which would cause saving of non-renewable energy resources and provide an alternate sustainable energy source.