Research On Reliable Location-transportation Problems For Hazardous Materials

As the basic and pillar industry of many countries,chemical industry plays an important role in the national economy and has a direct impact on all areas of the social-economic system.With the rapid development of chemical industry,chemical products have been widely used in agriculture,pharmacy,metallurgy,construction,energy,national defense and other industries,providing indispensable raw materials and products for the development of national economy.Generally speaking,most chemical products are hazardous materials(hazmats in short)which are explosive,flammable,toxic,corrosive and radioactive.Driven by the vigorous development of chemical industry,the hazmats logistics in China has achieved rapid growth and prosperity.However the frequent occurrence of hazmats accidents in the logistics process has sounded the alarm bell again and again,bringing huge losses and disasters to the society and the environment.According to statistics,hazmats accidents mainly occur in the process of storage and transportation,which are two important links in logistics system.Therefore,how to reduce the risk of hazmats logistics system through the integrated optimization of location and transportation has become a hot topic of the government,enterprises and academia.This paper takes the lead in introducing the reliable location problem into the hazmats logistics management,considering that the depots are subject to the risk of disruption.Based on the concept of comprehensive decision-making at the strategic and tactical level,this study takes the system risk and system cost as the optimization goal and focuses on the integrated optimization of reliable location and transportation for hazmats.The research contents include the following five aspects.(1)A reliable location allocation problem with single depot disruption is proposed for hazmats logistics.According to the characteristics of hazmats,an integer linear programming model is formulated to minimize the systemic risk of storage and transportation under budget constraints.Comparison experiment reveals the necessity and importance of taking reliability into account.Then the comparison with other similar approaches of reliable location problem shows the superiority of the proposed model.What's more,two statistical tests are conducted to illustrate the stability of the proposed model.Finally,case study reveals the necessity and importance of taking reliability into account and making contingency plans in disruption scenarios regarding the location allocation decision-making for hazmats.(2)A reliable location allocation problem with multi depots disruption is proposed for hazmats logistics.A two-stage integer programming model is constructed based on the set of depot disruption scenarios.This model can solve the problem that multiple depots are disrupted simultaneously and the probability of depot disruption can not be quantified.In the first stage,the rented depots,the amount of hazmats stored in the rented depots,and the allocation scheme under the scenario without disruption are decided,and in the second stage,the transportation scheme under depots disruption is formulated.The particle swarm optimization(PSO)algorithm,simulated annealing(SA)algorithm,and ant colony optimization(ACO)algorithm are designed to solve this model.Numerical experiments demonstrate that PSO algorithm achieves better performance than SA and ACO.(3)A reliable location routing problem with single depot disruption is proposed for hazmats logistics.In this work,the reliable location is introduced into the location routing problem of hazmats for integrated optimization.In view of three different priority scenarios of system risk and system cost,goal programming models based on hierarchical optimization are formulated.A hybrid algorithm based on PSO and Genetic Algorithm(GA)is designed to solve the model.Numerical experiments show that the PSO-GA-based hybrid algorithm is superior to S A algorithm and ACO algorithm.(4)A reliable location routing problem with multi depots disruption is proposed for hazmats logistics.According to the characteristics of hazmats logistics,a bi-objective programming model is formulated.This bi-objective optimization problem is solved by the weight sum method so that decision makers can achieve the best balance between system risk and system cost.The PSO-GA-based hybrid algorithm based on clustering is designed to solve this model.Numerical experiments show that PSO-GA-based hybrid algorithm based on clustering is much more efficient than the PSO-GA hybrid algorithm.(5)A reliable location routing problem with stochastic transportation risk is proposed for hazmats logistics.Since the transportation risk may follow different stochastic distribution,a stochastic chance constrained model can be formulated.The objective of this model is to minimize the systemic risk,and the chance constraint requires that the probability of the system risk less than or equal to a given threshold is not less than the confidence level a.The PSO-GA-based hybrid algorithm based on Monte Carlo simulation is designed to solve this model.Numerical experiments show that the proposed stochastic chance constrained model can significantly reduce the system cost compared with the deterministic models.This paper systematically investigated the problem of reliable location and transportation for hazmats from the multiple angles such as location allocation problem and location routing problem,single depot disruption and multi-depot disruption,deterministic transportation risk and stochastic transportation risk.It enriches a series of decision-making theories,such as reliable location problem,location allocation problem and location routing problem.It can be used to guide small and medium-sized enterprises to make scientific decision-making so as to reduce the risks and costs and improve the efficiency and competitiveness of logistics system.This study can not only promote the rapid and sustainable development of hazmats logistics,but also reduce the harm to society,environment and enterprises caused by hazmats accidents.Therefore,this paper has important research value and practical significance.