Research On The Simulation Of Circular Economy In Lanzhou City Based On System Dynamics

Due to economic,social,environmental protection and other constraints,the traditional"resource-product-waste" one-way mobile economic model has been unsustainable today.The massive waste of natural resources and the deterioration of ecological environment are forcing mankind to seek a more efficient and reasonable economic development mode.The"spacecraft theory" in the 1960s gave birth to the concept of circular economy.Due to its great advantages in resource utilization and cost saving,scholars at home and abroad have studied the development of circular economy from different perspectives.The circular economy system is a complex social economic system,and the factors that affect the system are numerous and complex.In general,the coordinated development of economy,population,resources,and environment has become a common consensus in the analysis of circular economy systems.This article introduced the research background of circular economy,systematically sorted out the theoretical results on circular economy at home and abroad,and paid more attention to circular economy and system dynamics theories etc;Based on the literature collection and organization above,the status of the development of circular economy in Lan Zhou city was introduced,and the key analysis of the four aspects of population-economy-resources-environment was carried out;For the questions existed in Lan Zhou,a dynamic system model of circular economy in Lanzhou City was constructed.Based on the determination of system boundaries,the city's circular economy system was divided into four subsystems:population,economy,resources,and environment,the causal feedback relationship diagrams,the flow charts of each subsystem and main equations were plotted and given,and from which 7 level variables,23 auxiliary variables,11 rate variables,15 constants,and 10 table functions were selected as parameters of the city's circular economy system model.Using Vensim software to simulate the numerical output and compared it with the historical data,it was proved that the model has good effectiveness and reliability;Finally,from the model,the birth rate,the tertiary industry investment ratio,the proportion of environmental protection investment and the proportion of reclamation,the rate of water resource recycling,and the reuse rate were selected as the control variables for the simulation of the circular economy.When changing the value of each variable in the simulation system within a reasonable range,observing the numerical output of the model.Based on the simulation results,targeted suggestions for the development of circular economy were given for Lanzhou city.