Mechanical Properties, Calorific Value, Proximate, and Thermal Analysis of Briquettes Made from Palm Oil Shell and LDPE with Varying Amounts of Adhesive

Indonesia is the world's largest palm oil-producing country, producing large amounts of palm shell waste. On the other hand, plastic waste is still a problem in Indonesia, and fossil fuels are increasingly decreasing, making all elements participate in providing alternative fuels. This research aims to solve these problems by making briquettes as an alternative fuel from palm oil shell (cangkang kelapa sawit or CKS) waste and low-density polyethylene (LDPE) plastic. Briquettes are made by varying the amount of tapioca adhesive to produce briquettes that can be compared to standard wood charcoal briquettes (SNI 1683:2021). Generally, briquette testing is limited to standard testing – namely calorific value and proximate analysis. Therefore, in this research, we carried out a more in-depth analysis by adding compression tests and thermal analysis (TGA, DTG, DTA) as a novelty in this research. Briquettes were made from CKS and LDPE plastic with variations of tapioca adhesive – namely 2, 3, and 4 g. Palm shell charcoal powder is made using carbonization. The briquettes were compacted at a pressure of 70 N/m2 for 30 min. One of the factors that influences the properties of briquettes is variations in the amount of adhesive; for that reason, we vary this adhesive. The mechanical analysis showed that briquettes with 4 g of tapioca adhesive had the best compressive strength compared to other briquettes. However, regarding the calorific value, proximate analysis, and thermal analysis, it is known that briquettes with 2 g adhesive have the best quality among other briquettes and meet SNI 1683:2021. The calorific value in this study ranged from 6729–6840 cal/g. These findings indicate that briquettes composed of palm shells and LDPE plastic with 2 g of tapioca adhesive have the potential as solid briquette-form fuel.