The Water Cycle Behavior Research Of Coal Based Large Scale Methanol Synthesis System

Along with the importance of energy-saving and waste reduction increasing, it was aroused considerable concern of industrial water wasting and serious inadequate problem. Methanol is an important organic chemical raw material and liquid fuel. The Coal to Methanol project is a large project which consume water and sewage seriously. At present, most coal chemical projects are built in Northwest China where water resources is very inadequate, so as rational utilization of water was their development choke point. Reducing fresh water consumption in Methanol Synthesis process is very important for the methanol industrial development. The amount of fresh water and wastewater emission were reduced to reach water consumption saving effect by the industrial wastewater recycling technology.A superstructure of the waste water regeneration and recycle network was established by the direction of water system Integration Principles and the mathematical model which composed of minimize the freshwater consumption model and minimize renewable pollutant load model on the basis of the superstructure was raised. Weighted factor,λs,which is coefficients considering many factors and can be adjusted by different design focus is introduced to represent the inequivalence, weighting coefficients. Furthermore, another mathematical model which use the minimal regenerated water flow rate as objective function, and the minimum freshwater and minimum contaminant regeneration load as the constraints is proposed based on the above optimization results. The programming was solved by the commercial software Lingo. The optimization thoughts of the network were provided by the results of this model. The optimization network can be adjusted by the implementation of feasibility, economic and other factors to against the actual problems.In this paper, which is supported by the preliminary designing of methanol equipment(200,000t/a) in Weihe River Coal Chemical Industry Group Co., Ltd and the actual operation data, the water cycle of Methanol Synthesis system was studied. Process modules of methanol synthesis system were the mainly investigated subject , and the fresh water, recycling of water, and wastewater in the system were expatiated and analysed, then water network was evaluated in order to obtain the water recycling network of the methanol synthesis system.It is creationary using the recycling network mathematical model in methanol synthesis system to reconstruct and optimize the existing water network and achieved a good water-saving effect in this paper.