Optimization of waste lubricating oil pyrolysis assisted by microwave and lignite activated carbon

Waste lubricating oil (WLO) of motorcycle is included in the category of hazardous and toxic materials. One alternative treatment that can be chosen to handle this waste is to process WLO into kerosene compounds. Kerosene has quite extensive uses, including being used as fuel or solvent in industry. This study aims to obtain optimum conditions for the pyrolysis process of waste lubricating oil into kerosene assisted by microwaves using microwave absorbents in the form of activated carbon (LAC) derived from lignite. The optimization design was carried out using the Box-Behkken method consisting of 15 experimental designs with 3 center points. The optimized process variables were temperature with variations of 400C, 450C, and 500C, microwave power with variations of 400 W, 600 W, and 800 W, and also the mass ratio of LAC to WLO with variations of 1:1, 1:1.25, and 1:1.5. The response variable in this study was analyzed using GC-MS and represented as a percentage of kerosene compounds with a carbon chain length of C10 − C16. Data processing using design expert resulted in recommendations for optimum conditions of temperature 400C, microwave power 800 W, and the ratio of 1:1.356 with a kerosene fraction reaching 89.374%. Laboratory testing of these optimum conditions resulted in a kerosene fraction of 85.41% with density characteristics of 808.0713 kg/m3 and a calorific value of 45.46 MJ/kg.