Cross Draft Gasifier

Cross draft gasifiers, although they have certain advantages over updraft and downdraft gasifiers, they are not of ideal type. The disadvantages such as high exit gas temperature, poor CO2 reduction and high velocity are the consequence of the design. Unlike downdraft and updraft gasifiers, the ash bin, fire and reduction zone in cross draft gasifiers are separated. The design characteristics limit the type of fuel for operation to low ash fuels such as wood, charcoal and coke. The load following ability of cross draft gasifier is quite good due to concentrated partial zones which operate at temperature up to 2000oC. Start up time (5 -10 minutes) is much faster than that of downdraft and updraft units. The relatively higher temperature in cross draft gasifier has an obvious effect on gas composition such as high carbon monoxide and low hydrogen and methane content when dry fuel such as charcoal is used. Cross draft gasifier operates well on dry blast and dry fuel.