Multi-period natural gas pipeline scheduling optimisation integrated with LNG cold energy cascade utilisation

Liquefied Natural Gas (LNG), as a vital form of natural gas resources, has exhibited a steadily increasing trend in global production and trade volumes. LNG terminals are facing the challenge of how to recover and utilise cold energy in a safe and efficient regasification process, while coordinating with the natural gas pipeline network transport scheduling. This study proposes an integrated regulation and collaborative optimisation approach for natural gas pipeline networks and LNG cold energy cascade utilisation systems. For natural gas pipeline network systems, P-Graph develops multi-period gas-electric interconnected supply chain network to optimise resource allocation. For the LNG cold energy cascade utilisation system, a dual Organic Rankine Cycle (ORC) framework for both power generation and refrigeration is developed, as well as thermodynamic analysis and heat integration techniques are applied to optimise system efficiency. Using a coastal LNG terminal in Zhejiang, China, as a case study, when the LNG regasification flow rate is 62.46 t/h, cold energy generates electricity of 2,335.94 kW and air-conditioning cooling load of 1,651.5 kW, system efficiency reaches 44.75 %. The peak regulation and gas storage effect of LNG is significant, which helps to alleviate that energy shortage in the region, and the coupled system of LNG and natural gas pipeline network improves energy utilisation efficiency and economic benefits for LNG industry chain.