针对干燥过程是一个高能耗的间歇单元操作,对多效干燥过程进行了排产调度研究。根据干燥速率曲线,将各效干燥过程设计为等操作时间,建立了多效干燥过程排产调度的优化模型。以效数和干燥器干燥时间为决策变量,以年费用最小为目标表达为一个混合整数非线性规划(MINLP)的数学模型,利用GAMS进行求解。以淤泥1~5效干燥为算例进行了优化调度分析,结果表明:在4效时年费用最小;与1效干燥相比,在最优条件下年生产费用可节约26%。同时获得了最优排产调度的Gantt图,从而可以得出干燥设备的最小操作周期,据此对多效干燥过程进行排产,使间歇多效干燥过程可以实现连续化生产,对多效干燥的工业化具有一定的意义。
Because industrial drying is one of the most energy-intensive batch unit operations,a scheduling plan of multi-effect drying was studied.Based on the rate of drying curve,operation time in each effect of multi-effect drying process was designed to be the same.An optimal plan and scheduling of multi-effect drying model was established.Defining the number of effects and the drying time as the decision variables,the minimum annual cost model of the batch n-effect drying process could be expressed as a mixed-integer non-linear programming(MINLP)problem,which could be solved by the GAMS software.An example of slit drying process(effect from 1 to 5)was analyzed with the model.The results indicated that the 4-effect drying was the optimal,and it could save 26% of the cost each year compared to the 1-effect drying.Optimal Gantt chart of scheduled process was also presented.According to the Gantt chart,the least period and the optimal operation process could be determined.It indicated that the batch multi-effect drying process could achieve continuous production.