Stability Optimization Of Hydrogen Networks In Refinery

The optimization of the hydrogen system in refineries is a significant issue with the tendency of heavier crude oils and stricter environmental regulations.One of the serious problems is the concentration fluctuation of hydrogen,which could affect product quality of refineries and cause financial losses.Therefore,it is of great significance to optimize the hydrogen network of refinery to solve the problem of imbalance between supply and demand of hydrogen,so as to improve the economic benefits of the refinery.On the basis of the previous studies,we introduce the multiple impurities mixing potential,WCVaR model and robust optimization model with adjustable hydrogen untility to design hydrogen network to obtain the hydrogen network structure with strongler disturbance resistant ability.The main contents and contributions are as follows:(1)The previously defined mixing potential of single impurity is extended to the multiple impurity case.Then the disturbance resistance ability is optimized under minimum hydrogen utility consumption by mathematical programming method.Later,such disturbance resistance ability of the obtained network structure is verified by Monte Carlo simulation.Several literature examples are investigated to illustrate the effectiveness of the method.Monte Carlo simulation results show that the disturbance resistance ability of the hydrogen network obtained by the proposed method is better than the literature performance in five cases,while one case stays the same.(2)The Worst-Case Conditional Value-at-Risk(WCVaR)concept which indicates possible minimum value of total pure hydrogen flowrate in hydrogen networks is introduced to improve the disturbance resistance ability of hydrogen network.The disturbance resistance ability is optimized in maximization of WCVaR associated with uncertainty distribution.The article can obtain the hydrogen network whose WCVaR is maximum for a fixed hydrogen utility consumption or not less than pure hydrogen requirement for more hydrogen utility consumption.The resistance ability of the obtained network structure is verified by Monte Carlo simulation.Literature examples illustrate that the hydrogen network optimized by the WCVaR model performs robustly.(3)The WCVaR model is applied to improve the stability of refinery hydrogen network when hydrogen utility can be adjusted.The hydrogen network structure with the smallest Fmax can be obtained by establishing an adjustable robust optimization model.Monte Carlo simulation can verify validity of this method.In practice,simply set the maximum hydrogen utility load and then adjust the hydrogen utility flow based on fluctuations in other hydrogen source flows.This will ensure hydrogen network stability while minimizing the amount of hydrogen utilities.