Effect of Pyrolysis Temperature and Adhesive Type on the Quality of Biobriquette from Coffee Stem Biomass

¹ Chemical Engineering Department, Faculty of Engineering, Universitas Sumatera Utara, Jalan Almamater Kampus USU, Padang Bulan, Medan 20115, Indonesia
² Industrial Engineering Department, Faculty of Engineering, Universitas Sumatera Utara, Jalan Almamater Kampus USU, Padang Bulan, Medan 20115, Indonesia

^* Corresponding author: rosdanelli@usu.ac.id

Abstract

Biobriquette is organic waste charcoal printed in such a way that has a high energy density and calorific value. The biobriquette quality is influenced by several factors, including the pyrolysis temperature and the adhesive type. This research aims to evaluate the effect of pyrolysis temperature (250°C, 300°C, and 350°C) and adhesive type (tapioca, molasses, and a tapioca-molasses mixture) on the quality of biobriquette from coffee stem. This research steps include pyrolysis of coffee stem, biobriquette production, and quality analysis of biobriquette. The biobriquette quality described refers to SNI No. 01-6235-2000, including water content, ash content, volatile matter, calorific value, and additional analysis, including fixed carbon, density, compressive strength, and combustion rate. This research shows that increasing the pyrolysis temperature will increase the charcoal yield. Pyrolysis temperature and adhesive type affect the quality of biobriquette. All biobriquette produced at a pyrolysis temperature of 350°C met SNI No. 01-6235-2000, in terms of water, ash, volatile, and heating values. The best biobriquette was obtained with a pyrolysis temperature of 350°C and tapioca adhesive, with water content of 2.45%, ash content of 2.35%, volatile matter of 1.24%, density of 1,345 g/cm³, compressive strength of 91.775 kg/cm², and a calorific value of 7,463.957 cal/g.