Study On The Water Pinch In The Reuse And Wastewater Mininmization Of The Refining Oil Plant

It is stringently urgent to deal with the difficulty of shortage of water resources in the economic construction in China, however, it can never be ignored that the loss and waste have intensified the shortage of water resources. Petrochemical industry is a big water consumer, even more, it is a big producer of wastewater. In China, the water consumption of processing one ton of raw oil is 2.43 m3, and the discharge of wastewater of processing one ton of raw oil reaches to 1.84 m3,comparing to the international average level, there is a great potential of saving water and reducing emitting pollutants in the petrochemical industry of the state. The paper studies the optimization of utilizing and recycling of water resources in an oil refinery, which has been put into use and have achieved fairly good economic profits and provided some experiences for other refineries in this field. Firstly, the paper presents a survey on fresh water network in the production facilities of the refinery, then draw a plot of the network, describes a balance chart of water consumption of specific facilities, which provides some basic data for the analysis of water usage. Secondly, the paper explains the application of water pinch technology and describes how the amount of minimum fresh water with recycling use and flow changes can be obtained by using a density interval diagram and a density complex curve. It shows that the higher of the limiting density permitted by the operation of water consumption, the lower of recycling water is required, which means more water can be used again, therefore, better economic profits of saving water can be achieved. Thirdly, the paper analyzes the coked water in details by applying the water pinch technology, meanwhile, it concludes the process of water recycling. Since the measures were put into use, the amount of water consumption in the coking facilities has been saved up to 83.3%, and the amount of wastewater has been reduced 66.7%. Consequently, the capital outlay has been recouped in less than nine months, and good economic profits have been obtained. Finally, the paper verifies the feasibility of recycling big drainage and filtering rinsing water through experiments, and concludes the regeneration technical of big drainage. Under the circumstances of lacking funds, some certain effects have also been achieved by restructuring process and choosing the recycle of big drainage. It is also an effective way of saving water and reducing drainage by recycling regenerated wastewater and providing high-quality water resources.