Experimental Study Of Multi-effect Distillation Oilfield Wastewater Desalination System

Aiming at high salinity of the oilfield waste water, one six-effect distillation system with the capacity of12t/d is designed and established. Through the experiments, exploring and syuding the feasibility of taking advantage of multi-effect evaporation technology to desalinate the oilfield sewage. From the viewpoint of resource conservation, energy utilization, environmental conservation, enhancing economic performance and cost reduction, this paper has important practical significance, which lays the foundation for the application of multi-effect evaporation technology adopted by petroleum enterprise.The following is the main work and conclusions in this paper:(1) The principle of horizontal tube falling film evaporation technology is explained. The flow of forward feed, countercurrent feed, advection feed and mixed feed is introduced.(2) Physical Model and Mathematical Model are built and sued to solved the parameters of each part. In addition, making use of Aspen plus to verify the accuracy of the simulating values.(3) Design and establish a six-effect ditillation system which is tower stype and forward feed, especially design the evaporation generate system, water recycle system and vacuum system and optimize on the heat exchanger, fresh water tank and electrical heater. The necessary instruments and meters are listed.(4) Stability test, thermal performance test and water quality test of NaCl are used for exploring the relationship between system performance and flow rate, temperature, concentration. The experiments verify the reliability, high efficiency and high purity. The following are the conclusions. With the increase of flow rate, the water production and GOR decrease. With the increase of feed temperature, production and GOR increase. However, concentration has no effect on water system performance. Fresh water quality is9-28ppm.(5) Analysis system for economy, value initial investment and operation cost. Initial cost spent mainly on plant construction. The cost can be decreased by choosing cheap materials, compact structure design, reducing the amount of materials. Test running cost is17.37RMBA. In practical industrial application, The cost is only the electric charge of the pump and vacuum pump. And then, the price is significantly reduced. In addition, the introduction of TVC can improve GOR, as well as reducing the cost further.