Abstract
In recent years, many coffee chain stores have opened nationwide, and it has become possible to drink drip coffee easily and
inexpensively at major convenience chains. However, there is a problem that a large amount of waste is left behind after the
extraction of coffee. In this report, in order to solve the problem of coffee grounds in small and medium-sized coffee beverage
factories, we examined the energy cycle of processing coffee grounds into Bio-coke and using it as a heat source. Bio-coke is
a biomass solid fuel that can be molded from various biomass feedstocks. With a relative weight yield of 100%, its volume can
be reduced and it can be stored for a long time. In addition, the manufacturing process is simple and suitable for small-scale
distributed use. As a result of examining energy circulation systems that use coffee grounds Bio-coke as heat sources for drying
coffee grounds and roasting coffee beans, we have found that this system is feasible. The coffee grounds used in this study had
a water content of 70 wt.% before drying and a water content of 2.0 wt.% after drying. Assuming that the low calorific value
of 1.0 kg of coffee grounds Bio-coke is 100%, the proportion of each energy required to make 1.0 kg of coffee grounds Biocoke
is as follows. The thermal energy required to dry the raw material moisture was 58.6%. The electrical energy useed to
heat and compress the coffee grounds to produce Bio-coke was 8.0%. As a result, it was found that 33.4% of the energy of
coffee grounds Bio-coke can be used effectively. If 13.1% of the energy is used to roast coffee beans and 0.1% is used to
transport coffee grounds Bio-coke, the remaining 20.2% can be used as heat energy for the extraction plant.
