Optimization Of Straw Supply Chain Under Supply Uncertainty And Facility Disruption Risks

China is rich in straw resources,and the comprehensive utilization of straw has broad prospects for development.As the current utilization of straw as fuel for directfired power generation has revealed many problems such as low combustion rate and high carbon emission,the use of straw for feed is getting more attention.Straw for feed,also known as "straw to meat",has effectively promoted the development of animal husbandry.Comprehensive utilization of straw is a process of turning waste into treasure.However,the low value of straw itself,plus the added high cost of its collection,storage,and transportation,which leads to low profits,makes its comprehensive use difficult.This paper takes a look at the raw material supply chain for Fermented Straw Engineering as a research objective,and aims to design a reasonable straw supply chain that can improve operation efficiency,reduce construction and operation costs for Fermented Straw Engineering while considering carbon emissions.The research results are of theoretical significance for the optimization of biomass raw material supply chain,and of practical significance and reference value for the network planning of straw recycling supply chain in Northeast China.The research approach of this paper goes from a deterministic model to an uncertain model.First,a site selection model of straw supply chain under certain conditions is proposed to obtain the optimum site,transportation amount and distribution results considering a dual objective of optimizing cost and carbon emission.Then,on the basis of the deterministic model,the uncertainty of the straw supply chain is analyzed,and a stochastic programming model considering the uncertainty of the straw collectible amount and facility failure is established.The results of the deterministic model and the stochastic model are compared and the sensitivity analysis is carried out.The research focus and innovations of this paper are mainly presented in the following three aspects:(1)From the perspective of long-term sustainable development of Fermented Straw Engineering,we analyze the characteristics of Feed Fermentation and its supply chain,and establish a multi-period dual-objective model to determine the number,location,and transportation plans of collection and storage facilities in the straw supply chain.The data of Siping City,Jilin Province,obtained from field research,is used for empirical research,together with the use of Arc GIS system buffer analysis and overlay analysis to process the map of Siping City for alternative points of storage facilities.In order to effectively solve the dual-objective model with two different units of carbon emission and cost,and to better describe the relationship between carbon emission and cost,NSGA-II heuristic algorithm is used to solve the dual-objective multi-period three-level supply chain model to reach the Pareto optimal frontier.The validity and applicability of the model are therefore verified.(2)On the basis of the deterministic model,the uncertainty of straw supply and failure risk of facilities are considered to establish a two-stage stochastic programming model of a multi-period three-level straw supply chain.When selecting the site,we firstly grade the alternative points of the collection and storage facilities,and then assign the alternative points for each level to prepare the alternative collection and storage facilities for the collection point and the fermented feed factory,in order to deal with possible insufficient supply of raw materials and the failure of collection and storage facilities.(3)We use the improved Fruit Fly Optimization Algorithm(FFO)to solve the random programming model and analyze it.In order to solve the uncertainty model,the standard FFO is improved by introducing the non-dominated sorting method of Pareto solution set into the adaptive step size strategy of FFO.The cross mutation and fast non-dominated sorting in Genetic algorithm(GA)are also introduced into FFO to prevent it from converging too fast,and being stuck in a local optimum.By using the improved FFO to solve the stochastic programming model,and comparing the results of the deterministic model and the uncertainty model,and the influence of uncertainty on the supply of straw forage was analyzed.When the shortage penalty is serious enough,it is necessary to establish more alternative collection and storage facilities,and at the same time,increase the inventory to meet the raw material demand of the fermented feed factory.In conclusion,this paper studies the supply chain of Straw Feed Fermentation in Siping City,Jilin Province,and demonstrates the relationship between the cost of Straw Feed Fermentation supply chain and the carbon emission target through a practical example.By comparing the deterministic model and the uncertain model,the overall optimization of straw collection,storage and transportation is accomplished.The comparsion betweetn different models clearly presents the influence of uncertainty on the supply chain.The results show that considering uncertainty is especially necessary for straw supply chain design,because it can improve the system efficiency,reduce the total cost of supply chain,improve the ability of supply chain to deal with the failure risk of facilities,andpromote the sustainable development of straw as a better source of feed.