Oil Sludge and Biomass Waste Utilization as Densified Refuse-Derived Fuels for Alternative Fuels: Case Study of an Indonesia Cement Plant

Abstract

The cement industry is considered as a high consumption source for industry that requires high productivity. On the other hand, imminent depletion of fossil resources is leading to the utilization of alternative fuels. The utilization of oil sludge as hazardous waste and biomass waste (coconut shell and rice husk) that have been processed into densified refuse-derived fuel (D-RDF) form is evaluated in this research paper. The calorific value of oil sludge, coconut shell, and rice husk were found to be 6,298.86, 3,528.22, and 3,381.92 kcal/kg, respectively. The objective of this research was to determine the optimum D-RDF mixture based on calorific value, moisture content, chloride content, and stable solid physical form. Oil sludge:biomass ratios trialed in this research were 1:1, 1:2, 1:3, and 2:1 by weight combined with 5% starch as an adhesive. According to the criteria stated previously, the optimal combination for D-RDF for the cement industry was a 1:1 mixture of oil sludge and coconut shell, which provided 6,413 kcal/kg, had a 9.8% moisture content, and a chloride value of 1.07%, which is above the applicable quality standard of the Indonesian Ministry of the Eenvironment’s regulation no. 02 (2008) and European Union for Responsible Incineration and Treatment of Special Waste (EURITS). This combination has a solid pellet form when shaped with a 5 mm diameter, average length 15 mm, and highest density 0.9562 g/cm3, making it easy to store and transport to the firing point.