Design and Development of a Blower for Downdraft Biomass Gasifier

Abstract

Inadequate and improper supply and control of air are major causes of failures in gasifiers. Lack of adequate number of blowers as well as tge use of unsuitable type of blower also lead to the total collapse of the gasification process.This research presents the design of a blower for use in the operation of a batch type downdraft gasifier, using analytical and numerical methods from the literature. The basic air requirements for gasification were considered as input parameters in order to determine the impeller design parameters. They included the geometrical parameters such as the tip diameter, hub diameter and tip width; operating conditions such as the inlet total pressure, inlet total temperature and fluid density; and performance characteristics such as mass flow parameter, pressure ratio and specific speed. The blower’s physical characteristics , geometric parameters and performance parameters were found and calculated to be β1, β2,U1, Vr2, as 42o , 90o, 17.52 m/s, 26.2 m/s and ; d1min, d2, Z as 186 mm, 190 mm, and 8; while Q, P, N, as 0.5m3/s, 221W, 2800 rpm and 85.1% respectively. To accommodate the parameters calculated and ensure optimal performance of the blower, a 0.5 HP motor was selected and used. However, as blowers are generally associated with some problems such as vibration, lack of performance, excessive noise and premature component failure, extensive tests will be carried out.