Coffee roaster usually developed by use of oil fuel, LPG, or electricity as heat resources. Nowadays these resources are tends to limited and expensive. The use of gas produced from biomass gasification for coffee roasting is an appropriate alternative as it is cheap and environtmentally sound. This research was done to determine the design and operational parameters of horizontal tube coffee roaster heated by combustion of gas of biomass gasification.
The experiments were conducted by modifies the LPG based horizontal tube coffee roaster to the biomass gasification stove based coffe roaster. The experimental variations were length of tube, rate of gasification air input, dimension of coffee bean, and weight of coffee per batch of roasting. The roasting performance measured were final moisture content and colour of the roasted coffee bean.
The results showed that the heat of combustion of gas produced from biomass gasification could be employed to substitute the LPG. The quality of roasting was similar as light to medium roast. The heat transfer process from gasification stove to the roaster tube should more be improved by modification of stove, that is enlarging burning area of gasification stove. In the operational aspect, the rotation speed of roaster tube could be set lower to match the heat capacity of gasification stove.
Keywords: roaster, coffee, biomass gasification, performance, uniformity
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