International Journal of Advances in Applied Sciences (IJAAS) Vol. 13, No. 4, December 2024, pp. 1000~1008 ISSN: 2252-8814, DOI: 10.11591/ijaas.v13.i4.pp1000-1008  1000 Journal homepage: http://ijaas.iaescore.com Pyrolysis of biomass mixture of coconut fiber and rice husk waste with polypropylene plastic Bagas Cahya Mardikatama, Danar Susilo Wijayanto, Taufik Wisnu Saputra Mechanical Engineering Education Study Program, Faculty of Teacher Training and Education, Sebelas Maret University, Surakarta, Indonesia Article Info ABSTRACT Article history: Received May 7, 2024 Revised Aug 30, 2024 Accepted Sep 4, 2024 This research aims to evaluate the effect of the composition ratio of oil from coconut fiber waste biomass and rice husks as well as polypropylene (PP) plastic which is not optimally utilized and can be used as an alternative fuel processed through the pyrolysis process. This research was conducted by mixing biomass of coconut fiber and rice husk with PP plastic in the form of refuse-derived fuel (RDF)-3 with compositional variations of 100:0%, 75:25%, 50:50%, 75:25%, and 0:100% for 60 minutes. The pyrolysis product in the form of oil was then distilled to separate the compounds contained in it and produce pure oil. Next, quantity (volume of pyrolysis oil and distilled oil) and quality (yield, density, viscosity, visual, and color) tests were carried out. The results of the study showed that there is an influence of the variation in the composition ratio of the mixture of biomass of coconut fiber and rice husk and PP plastic on its quantity and quality. The highest quantity was obtained from the 100% PP ratio and the best quality was obtained from the 100% PP ratio, which leads to the specifications of solar fuel oil. Keywords: Biomass Coconut fiber Rice husk polypropylene pyrolysis This is an open access article under the CC BY-SA license. Corresponding Author: Danar Susilo Wijayanto Mechanical Engineering Education Study Program, Faculty of Teacher, Training and Education Sebelas Maret University Ahmad Yani St. No. 200 Pabelan, Kartasura, 57161, Surakarta, Central Java, Indonesia Email: danarsw@staff.uns.ac.id 1. INTRODUCTION All countries in the world are facing the big challenge of energy scarcity. Significant depletion of oil reserves is at the root of this problem. World energy demand continues to increase and has become a global problem in energy use in various sectors, resulting in an energy crisis [1]. Population growth affects energy consumption to meet transportation, industrial, and household needs [2]. The massive consumption of petroleum fuels depletes these energy sources and creates environmental issues due to the increased pollution emissions from burning these fuels [3]. The world's energy demand currently reaches 3×1,020 Joules/year and is predicted to continue to increase to 30 Terra Watts by 2030 [4]. Excessive use of fossil energy sources can lead to the depletion of fossil energy reserves must be immediately offset by the abundant supply of renewable, cheap, and affordable alternative energy for the general public [5]. Experts predict that fossil fuels will soon run out with current consumption patterns. By 2052, oil will be depleted, gas forty years later, coal seventy years later, and by 2090, coal is expected to be exhausted [6]. Reducing reliance on petroleum is possible via the use of renewable energy sources, which are abundant in Indonesia, rather than oil. As a renewable energy source, biomass is one option [2]. Exploring different forms of alternative energy is necessary to keep up with the ever-increasing demand for power. One option is to make use of biomass, which is a byproduct of farming, plantation, or forest operations. As a nation that