Layout Optimization Of China’s Imported Grain Distribution Center

Grain is the main processing object and important raw material of light industry.China’s grain supply pressure is significantly increasing due to the demand for food grain,feed grain and industrial grain caused by the improvement of the development of light industry and people’s living standards.The issue of the grain security is always the concerned focus of the Party and government.China is striving to increase domestic grain production while also increasing grain imports.Since 2014,China’s annual grain import has been maintained at more than 100 million tons per year.In 2021,China imported 164.54 million tons of grain,accounting for 24%of the total national grain output,and while external dependence on grain was 19.4%.Imported grain nowadays faces logistics problems such as transportation,storage and distribution in China.The Chinese government therefore has issued policy documents to continue widening the international grain market,and building grain import logistics channels and important nodes,improving the efficiency of grain logistics and ensuring China’s grain security.The layout of China’s imported grain distribution(IGD)center and the construction of an efficient IGD network that radiates across the country can effectively undertake international grain resources,fully utilize the domestic grain logistics system,improve the quality of life of residents,and improve the economic efficiency of grain processing enterprises.Based on multiple perspectives of modern logistics,the theories of complex network,hub-and-spoke logistics network,multi-attribute decision-making,as well as the operation research optimization,this paper reviews the levels of intermodal transport capacity,city development,grain logistics,traffic CO2 emission intensity,as well as other indicators.These data outline the grain logistics performance in node cities,and reflect the improved Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS)as entropy model,VIsekriterijumsko KOmpromisno Rangiranje(VIKOR)as evaluation model,Ordered Weighted Average(OWA)as operator model,as well as K-means Clustering,Logistics Gravity and Mixed Integer Programming models to identify key node cities as China’s IGD centers and lay out the IGD network.The main research work and findings of this paper are as follows:(1)The China’s IGD centers are laid out according to the multimodal transport network between the node cities.First,23 important logistics node cities were selected as China’s IGD nodes according to the national policy documents such as the List of Designated Ports and Inspection Points for Imported Grain,the 13th Five-Year Plan for the Development of the Grain Logistics Industry,the China Railway Express Construction and Development Plan(2016-2020),and the National Circulation Node City Layout Plan(20152020).Second,the improved entropy TOPSIS is used to evaluate the degree centrality,closeness centrality,betweenness centrality,and eigenvector centrality,and rank the China’s IGD nodes using the complex network theory applied to,the multimodal transport of imported grain by road,freight rail,and water between the node cities.Finally,Guangzhou,Lianyungang,Shanghai,Tianjin,Chongqing and Xi’an,are selected as China’s IGD centers within operation of China Railway Express and in light of the "Belt and Road" policy,the importance and the grain distribution radiation capacity of nodes.(2)The China’s IGD centers are laid out according to the grain logistics channel where the nodes are located.First,the 5 imported grain logistics channels,including the northeast channel of imported grain,the northwest channel of imported grain,the southwest channel of imported grain,the Bohai Rim channel of imported grain,and the southeast channel of imported grain,are constructed according to the direction of China’s imported grain and domestic grain logistics regulatory bodies.Second,the 4 evaluation indicators of the development level of the grain industry(grain output,inter-provincial transfer capacity of grain,grain processing capacity,and the number of imported grain processing enterprise)are established.Also the VIKOR evaluation model is used-all to select the representative provinces for grain industry development(Heilongjiang,Xinjiang,Sichuan,Shandong and Jiangsu)in imported grain logistics areas.Finally,the evaluation indexes of grain logistics capacity for transportation infrastructure,city positioning and logistics level,are established,and the VIKOR evaluation model was used to select five cities from the representative provinces for grain industry development,namely Harbin,Urumqi,Chengdu,Qingdao and Nanjing,as the for China’s IGD centers.(3)The China’s IGD centers are laid out according to the logistics hub-andspoke network relationship between the node cities.First,the 54 primary grain logistics node cities are determined as China’s IGD nodes(in light of the 13th Five-Year Plan for the Development of the Grain Logistics Industry)and arranged along the key grain logistics routes.Second,the 6 evaluation indexes of IGD capacity,including economic development,logistics industry scale,logistics position,imported grain processing,grain storage,and city informatization,are constructed using OWA operator model.This helped comprehensively evaluate and rank the IGD capacity of the distribution nodes in China.Third,the K-means Clustering model is used to select eight citiesGuangzhou,Qingdao,Shanghai,Nanjing,Changsha,Harbin,Chengdu and Tianjin-as the China’s IGD centers,according to the characteristics of the evaluation indicators of the IGD capacity of China’s IGD nodes.Finally,according to the hub-and-spoke logistics network theory it takes the China’s IGD centers as the hub nodes,and the designated ports of import grain and demand regions of imported grain as the spoke nodes,and then the Logistics Gravity model is used to build the hub-and-spoke logistics distribution network for China’s grain imports.(4)To optimize the layout of the China’s IGD center the Mixed Integer Programming model is used.First,the China’s IGD centers determined by various perspectives and theories in the previous chapters are combined to select 12 cities--Shanghai,Guangzhou,Qingdao,Lianyungang,Harbin,Urumqi,Xi’an,Chengdu,Chongqing,Changsha,Nanjing and Tianjin-as the China’s IGD centers.Second,the layout optimization model of China’s IGD center is constructed based on the mixed integer programming theory which minimizes the total construction and operation cost for the IGD center,the transportation cost and the social cost for transportation CO2 emission of imported grain.This helps determine Tianjin,Lianyungang,Shanghai,Chongqing and Xi’an as the final optimization results of China’s IGD centers.Finally,the sensitivity analysis is carried out according to different parameters and including the construction cost of China’s IGD center,the unit transportation price of imported grain and the unit CO2 emissions under different transportation modes.The research on the layout optimization of China’s IGD center is conducive to integrating international grain resources,utilizing the human,financial,material,and infrastructure of the domestic grain logistics system,improving the level of regional grain logistics,meeting the diversification of grain demand of people and enterprises in various regions,ensuring national grain security,and improving the production efficiency of light industry in China.This paper can provide theoretical support for the national grain logistics policy and also serve as a reference for the layout of distribution centers for other light industrial products in China.