To achieve cleaner production in palm oil mills (POM), eliminating palm oil mill effluent (POME) via evaporation provides promising benefits towards palm oil sustainability. The incorporation of POME evaporation creates circular economy opportunities between mill, refinery and cogeneration system via converting mill-refinery effluent to oil recovered-solids and regenerated water, broadening biomass-to-energy potential to support energy-extensive evaporation and water integrations. Such industrial symbiosis scheme named as the integrated palm oil-based complex (POBC) could consider participation from different companies to provide desired processing facilities in achieving the optimal performance of POBC. For the new POBC scheme, the individual interest for each participating facility is hard to define due to the lack of basis for profit distribution. It is crucial to propose an optimal business model for POBC planning to demonstrate the financial allocation among possible partners based on the pooled incremental gains in the POBC coalition. The business model serves as a tool to persuade the companies in collaborating by quantifying their potential economic benefits and contributions for negotiation before forming the POBC. The cooperative game theory model has been useful in distributing cost savings within a coalition of individual plants. On that account, an integrated cooperative game-based optimisation approach is proposed to optimally distribute the profit gain and investment sharing between POM, palm oil refinery and biomass-cogeneration system to develop a feasible business model for a multi-owner POBC. Seven scenarios have been evaluated to generate optimal multi-owner POBC business models achieving 7-13 % improvements in economic potential. The average economic allocations of collaborating POM, refinery and cogeneration system are 91.8 %, 2.4 % and 5.8 % in the multi-owner POBCs.