Experimental Investigation and Simulation of Slow Pyrolysis Process of Arabica Coffee Agroindustry Residues in a Pilot-Scale Reactor

Coffee pulp and husk are the primary residues of the coffee agro-industry. Disposing of them into the land can bring a serious problem on the environment. Strategies are needed to convert it into more valuable products as well as reduce the risk of environmental damage. This paper reports experimental and simulation investigation on the pyrolysis of Gayo arabica coffee pulp and husk in a pilot scale reactor. The investigation included finding the chemical and physical properties of biomass under ultimate, proximate, bomb calorimeter and TGA analyses. During the pyrolysis experiments, 3 kg of dried raw material was fed into the reactor and heated from room temperature to 600 °C, then held for 2.5 h. Afterwards, the resulting biochar and pyrolytic oil ware quantified for product distribution analysis. Modeling and simulation of the pyrolysis process were performed using Aspen Plus V10 software. Experimental results show that biochar is the main product giving a yield of 43.83%. The percentage of pyrolytic oil and un-condensable gas products are 25.5% and 30.67%, respectively. The thermodynamic simulation shows a good agreement with the experimental result, which helps in optimization and scaling up reactor.