The Effect of Lifters, Inclination Angle and Rotational Speed on Residence Time of Rotary Kiln for Torrefaction Process

Abstract

Torrefaction process is the innovation to improve the properties of biomass. Residence time is one of the parameters that affects the properties of torrefied biomass. The residence time of a rotary kiln is the time of biomass drop into the cylinder until getting out of the cylinder. So, the propose of this study is the effect of lifters, inclination angle and rotational speed on the residence time of a rotary kiln for the torrefaction process. Palm kernel shell was used in this research. Palm kernel was chopped and minced to reduce size. The rotary kiln (0.3 meters diameter 6 meters in length) was used in this research. The number of lifters in this research were 0, 1 and 2. The rotational speed were 1, 2 and 3 rpm. The inclination angle was 1, 3 and 5 degrees. The hopper was used for the feeding system. The time was collected from biomass drop into the cylinder until getting out of the cylinder. The results reveal that the number of lifters, rotational speed and inclination angle affects the residence time of the rotary kiln. The residence time of rotary kiln was an increase when the number of lifters increase. The residence time of the rotary kiln was decreased when the rotational speed and inclination angle increase. It can be concluded that the least residence time of rotary kiln was 86.94 minute at 0 lifters, 3 rpm and 5 degrees. The most residence time was 9.22 minute at 2 lifters, 1 rpm and 1 degree.