Research On Slab Scheduling In Reheat Furnace And Hot Rolling Considering Energy Consumption

The reheat furnace-hot rolling production process is an important part of steel production,and its production process has typical characteristics of complex production process,high temperature and high energy consumption.The slab schedule in the reheat furnace and the hot rolling process has a direct impact on the production changeover cost.On the other hand,in the actual production process,the coil schedule has a great influence on the energy consumption of the hot rolling production line and the reheat furnace.By considering energy consumption in the production schedule making process,the total cost of production and energy will be effectively reduced.This thesis studies slab scheduling problem in reheat furnace and hot rolling,from both the integrated and two-stage perspectives.The problem is to decide the slab schedule in order to minimize the total production and total energy costs,under the production process and energy restrictions.For the case in integrated perspective,a mixed integer programming model is established.From the two-stage perspective,a column generation based algorithm is developed for the slab scheduling problem in reheat furnace,;an improved tabu search algorithm is proposed to solve the slab scheduling problem in hot rolling line,.The main work of this thesis includes:1)For the slab scheduling problem in reheat furnace and hot rolling,a mixed integer programming model is established considering the production and energy constraints,with the target of minimizing the total cost of production and energy,;since the model objectives include nonlinear terms,the model is linearized.Then,the model is solved using CPLEX,and the validity of the model is verified by experiments.Considering the complexity of the integrated model,the problems is studied in two stage perspective later.2)For the slab scheduling problem in hot rolling,the mathematical model is established aiming at minimizing production cost,and a fusion tabu search algorithm and fruit fly optimization idea are proposed to solve the problem.The experimental results show that the proposed improved tabu search algorithm can find the optimal solution for small-scale instancess in the reasonable time,and can find near-optimal solutions for large-scale instances,which can meet the actual production needs.3)For the slab scheduling problem in reheat furnace,a set partitioning model is established,and a branch and price algorithm based on column generation is proposed to solve the problem.For the sub-problem,a dynamic programming algorithm is designed.The integer solution of the primal problem can be achieved by branching,and finally the effectiveness of the algorithm is proved by experiments.