Two-stage stochastic programming for the refined oil secondary distribution with uncertain demand and limited inventory capacity

In recent years, more and more oil companies adopt initiative delivery mode to make the refined oil secondary distribution scheme. In this work, we focus on the optimization problem of refined oil secondary distribution based on the initiative distribution mode considering stochastic demand and the limited inventory capacity of each petrol station. We present a two-stage stochastic programming model that determines the replenishment quantity of each petrol station based on its existing stock and the available supply quantity of each oil depot, as well as transportation schedule. When the uncertainty in demand can be captured via a finite set of scenarios, the two-stage stochastic programming model is transformed into an equivalent deterministic mixed integer programming model that can be efficiently solved by CPLEX solver. The effectiveness of the two-stage stochastic programming model is verified by simulation on extensive computer-generated instances. To solve practical problems with a large number of scenarios, we propose a method to reduce the problem scale by merging similar scenarios. We demonstrate that compared to the optimal solution obtained from the model with all scenarios, the gap corresponding to the model with merged scenarios is always less than 1%. The results of the sensitivity analysis show that an increase in the inventory capacity leads to a decrease in the total cost within a certain range. The results of this study can help companies making refined oil secondary distribution plan.