The objective is to produce the biomass pellet fuel from coffee silverskin and spent of coffee grounds. To study the percentage of cassava powder as binder was mixed at 5 10 15 and 20% by weight and the best condition was chosen. Then to study the ratio of coffee silverskin and spent of coffee grounds was 5 ratios (100 : 0 75 : 25 50 : 50 25 : 75 and 0 : 100) on propertied of biomass pellet fuel. Characteristics and properties of raw materials and biomass pellet fuel were analyzed. The results found that the highest property of the biomass pellet fuel was 20% of cassava powder as binder. The biomass pellet from spent coffee grounds as main component was higher quality than coffee silverskin. The biomass pellet from spent coffee grounds was the maximum fuel property. The bulk density was 0.9699 􀁳 0.0045 g/ cubic cm shatter index was 92.6510 ± 0.2102% heating value was 17.2772 ± 0.0319 MJ/kg and heat utilization efficiency was 16.59 ± 0.02%. The results from the part of coffee silverskin and spent of coffee grounds ratio showed that the best ratio from 2 raw materials was 25 : 75 that gave the highest quality. The heating value was 17.1544 ± 0.017 MJ/kg and heat utilization efficiency was 16.48 ± 0.01%. In addition the study also discovered that the biomass pellet had moisture contents in the levels acceptable under biomass standards. Thus in summary the coffee silverskin and spent coffee grounds had physical property and fuel property according to the standardization to be made into biomass pellet fuel. It considered to be one of alternative fuels in country permanently.

In the procedure processes of Robusta coffee initial from bring the green coffee after dried and removed the outside shell and bring it to separating process. The sale price depends on the size of green coffee. If their size of still standard the sale price have been increased. Most of the separating process is majorly with the labor experience. Based on human experience the error with operating and working time is increased. In this reason we will study to the criteria of Robusta coffee for designing and creating the Robusta coffee bean separator machine for Robusta size standard testing. The separator machine consists of the three-layer cylindrical sieve set and the diameter of the layers was 4 6 and 7.5 mm. respectively. For the standardization of Robusta coffee bean is controlled by size of hole sieve. In this research considers to 4 importance parameters by the efficiency of sorting out standard of green coffee Specific Energy Consumption [SEC] and assessment way economic engineering. The result of research shows that the maximum efficiency of green coffee separating is 164.7 kg/hr under the condition of testing with 14.4 rpm at 4 angle incline. In term of standard it found that the machine can separated only for standard and smaller than standard size of green coffee and the maximum moistness are 9.9%. For the least Specific Energy Consumption [SEC] is 0.01631 MJ/kg and occur with the same condition of experiment. Based on this condition the Break-Even Point must be sorting out with 1070550 kilogram per year and Payback Period will occur at 3.598 years. However the quantity of separating or the efficiency of machine is mainly effect to Break-Even Point and Payback Period.