Systematic Method to Synthesise Optimum Hydrogen Network for Integration of Pyrolysis-Based Bio-refinery and Existing Petroleum Refinery

The integration of pyrolysis-based bio-refinery and existing petroleum refinery has previously been proven to provide economic advantage in terms of the capital and operating costs relative to the stand-alone bio-refinery plant scenario. This economic advantage can still be enhanced further via hydrogen integration between the integrated refineries given the large amount of hydrogen consumption in hydrotreating and hydrocracking units in both refineries. This work thus proposed a superstructure-based mathematical model for integrating pyrolysis-based bio-refinery and existing petroleum refinery that also concurrently addresses the synthesis of optimum hydrogen network to meet the hydrogen requirement of the integrated refineries. The model is formulated in mixed-integer nonlinear programming (MINLP) form and is solved using LINDOGLOBAL solver in GAMS platform. The application of the model is illustrated using literature-based case study where up to 35.07% of reduction in hydrogen plant size can be achieved relative to the base case stand-alone bio-refinery scenario. The relationship between the profit and the bio-refinery size showed that the scenario where the stable pyrolysis oil (St-oil) from the bio-refinery can be processed inside the existing petroleum refinery catalytic cracking unit is more economically attractive than the scenario where the bio-refinery can share materials only with the existing petroleum refinery blending pool.