Biocrude from Hydrothermal Liquefaction of Indigenous Municipal Solid Waste for Green Energy generation and contribution towards Circular Economy: A Case Study of Urban Pakistan

Highlights•Production of BioCrude oil from MSW by HTL Process.•K2CO3 Catalytic Process: 22.61 % yield of biocrude oil yield with 28.61 MJ/kg heating value.•Solid Waste Contains: 78 % dry, 22 % moisture, 22.2 % ash, 22.69 MJ/kg HHV, 52 % Carbon, 8 % Hydrogen.•Biocrude contains approximately 80 % of volatile fractions of different fuels.•Biocrude majorly contains 25.74 % Ethyl ether, 9.08% 2-pentanone, 4-hydroxy-4-methyl and 5.62 % 2-Propanone, 1,1-dimethoxy.AbstractIn this study, biocrude was successfully produced by the hydrothermal liquefaction of municipal solid waste collected from the landfill site of Lahore, the capital of Punjab, Pakistan, boasting a population of 12 million and an annual waste collection of 10 million tons. The hydrothermal liquefaction process was performed at reaction parameters of 350 °C and 165 bars with 15 min of residence time. The solid waste was found to have 78 % dry matter, 22 % moisture contents, 22.2 % ash, 22.69 MJ/kg higher heating value, 52.062 % C, 8.007 % H, 0.764 % N, and 39.164 % O. Non-catalytic process only produced 10.57 % oil, however when using the catalytic process, the biocrude yield improved to 17.61 %, with 22.61 % energy recovery for biocrude and 12.14 % for solids, when using 2 g dose of K2CO3. The resultant biocrude has a 28.61 MJ/kg higher heating value, having 60.28 % C and 9.28 % H. In contrast, the aqueous phase generated had 4.43 pH, 71.5 g/L TOC, and 1.35 g/L Total Nitrogen. TGA indicated that biocrude contains approximately 80 % of volatile fractions of different fuels. The organic compounds having the six highest peak areas in GC-MS were Ethyl ether 25.74 %, 2-pentanone, 4-hydroxy-4-methyl 9.08 %, 2-propanone, 1,1-dimethoxy 5.62 %, Silane, dimethyl (docosyloxy) butoxy 5.08 %, 1-Hexanol, 2-ethyl 4.53 %, and. Phenol 4.07 %. This work makes the first-ever successful use of indigenous solid waste from a landfill dumping site in Lahore to successfully produce useful biocrude with aims of waste reduction and management, circular economy, and energy recovery.Graphical abstract