Optimization Research Of LNG Maritime Inventory Routing Considering Uncertainty Delay

Natural gas,as a clean fossil energy,is of irreplaceable strategic significance for ensuring the security of national energy supply and tackling climate change.As a major' natural gas consumer and importing country in the world,in order to achieve a low-carbon economic transformation,the future demand for natural gas and dependence on imports will also increase,while most of China's liquefied natural gas trade is realized through LNG ships by sea transportation.In the sea transportation process,unpredictable interruption delays often extend the ship's navigation time between ports,which ultimately leads to the ship's inability to complete the delivery within the specified delivery time window.Therefore,the uncertain factors of LNG in the transportation process have an increasing impact on transportation,which has attracted considerable attention.Based on the background of the supplier inventory management system(VMI)and the shipping inventory-routing problem(MIRP),this paper studies the shipping inventory-routing problem with delivery time windows and uncertain interruption delays.At the same time,taking the annual delivery plan for LNG(LNG-ADP)as an example,after the LNG supplier has confirmed the delivery transportation contract,the delivery time window and total delivery quantity of the delivery port cannot be changed,but in order to deal with the voyage The uncertainty of the corresponding transport route can be adjusted later.The research goal of this paper is to develop a flexible path planning method that can resist uncertain interruption delays.To this end,the uncertain delay factors are considered at the tactical level,and two stages based on optimal path cost planning and recovery after delivery delays occur model.The first stage model is the classic ocean inventory-route problem,that is,the route planning study is carried out at the route planning level to meet the delivery quantity within the delivery time window and the port inventory capacity constraints.At the level of solving algorithm,design Lagrange heuristic algorithm.The algorithm uses Lagrange multipliers to integrate planning strategies that increase the flexibility to deal with uncertain interruption delays into the objective function,and makes simplified calculations for them.The second-stage recovery model is based on the first stage,and uses simulation experiments to simulate the uncertain interruption delay events that occurred during the voyage and the ports along the way.Once the uncertainty interruption delay occurs in the simulation,the recovery model will plan the route delivery plan for the remaining planned dates of the ship.By observing the subsequent solution results of the recovery model,it can be confirmed that the impact of the uncertain interruption on the original path planning plan is considered.This article considers the impact of the uncertainty of ship's sailing time more fully during the voyage.The experimental results show that if the consideration of the risk of delay due to weather uncertainty is added during the planning stage,although a small part of the cost will be increased,when the delivery delay occurs,the cost increase can be significantly reduced.