| Sewage in the oil field contains so much oil sludge and sulfide, which will cause serious pollution to the environment if they are discharged directly. So the secondary treatment to the sewage in the oil field is attached more and more importance. The ultimate purpose of the treatment to the sewage is to remove the oil from water, suspending objects and other ingredients which easily corrode water injection system. There are a dozen of methods to treat Oilfield sewage, like bioanalysis, gravity separation and froth floatation and so on. The water ingredients in oilfield are much too complicated and different and the qulity of processed recycled water is also completely different. Therefore, the treatment technology should be selected properly. The new tendency of the treatment to the oilfield sewage is focused on manufacturing new equipment and medicine to treat sewage, developing new process and applying the new treatment technology.It has solved two big troubles by treating the oil sewage and recycling water: one is the water resource recycled, the other is the emission and treatment of oil sewage. During the constant production practice, people come to realize that it is the right way to treat the oil sewage and recycle water after the water quality meets the standard.I will introduce a general treatment to the oil sewage and elaborate the specific requirement of sewage treatment and water recycling on measurement and control technology according to the process of sewage process and water recycling of Pingbei multi-purpose station of Yan’an City. I put forward the level-2automatic control system which is based on industrial computer (IPC) and dsPIC30F4013, and make a detailed description about how to achieve the realization of measurement and control principle, method, the corresponding hardware circuit and software design according to these specific techniques.At the same time, on account of requirement of sewage treatment and water injection, I put forward the following several advanced control algorithm, including: automatic dosing control algorithm of chemical drug dosing quantity, stability and control algorithm of the process, and constant pressure control algorithm the pump and so on. This paper estimates the control model of control object and also makes use of Matlab emulation tools to emulate the design of controller, and make a theoretical analysis of the emulation results.It introduces the control system centering on the dsPIC30F4013microcontroller in the system hardware circuit design, the channel of simulation signal acquisition, the channel of simulation control output, the channel switch input and output, communication interface and electrical control circuit and other specific circuit design, and it also gives the relevant interface program realization. At the same time, this paper expounds production management software which bases on the IPC workstation of Visual Basic6.0, and gives its overall structure and related software realization. Finally it describes the operation analysis of the practical production, and compares the water quality before the premodification and that after modification, which shows that sewage treatment and water injection system of Pingbei multi-purpose station are monitoring the process of wastewater treatment and water injection while it has effectively controlled the controlled variable, and also tested the application of the kinds of control algorithm in the system so as to achieve the expected goal. The system that appears in this paper has been applied in Pingbei multi-purpose station in Yan’an City, Shanxi Province. Since it was put into production in December,2010, the system has been stable and its effect of measurement and control is good. |
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