Research On An Artificial Seawater Purification System And Its Purifying Process Control

This paper aims at design of an artificial seawater purification system, which is one of ancillary facilities for basic research on the marine environment of a research institute. This paper mainly studies the design of the purifying process control, the design and project approachment of an artificial seawater purification system.Generally physical filtration and chemical disinfection are commonly used methods of water purifying treatment, while the methods of UV and ozone disinfection are used in condition of higher requirements. In this paper physical filtration in combination with UV and ozone disinfection was used to treat the artificial seawater, so that its purification quality can be guaranteed by means of PLC and HMI technology automatically controlling the artificial seawater purifying process.According to the design requirements, the purifying process can be divided into 4 relatively independent cases, which are 1-initial operating case making preparation of the artificial seawater with certain volume and salinity, 2- increased salinity case using circulating seawater to dissolve a certain amount of sea salt for increasing the salinity, 3-circulating seawater purification case using conventional methods combined with UV disinfection and ozone disinfectant to ensure the purification quality, 4-salt reduction or discharge case discharging certain amount of artificial seawater into the salt recycling field to recycle the salt by vaporization under sun exposure in order to prevent pollution of rivers and lakes caused by discharging the artificial seawater.This paper presents the schematic design of an artificial seawater purification system and its project approachment. First of all, the main procedure of artificial seawater purifying process has been planned. Secondly, the main parameters of the unit facilities on flocculation and precipitation process such as dosing pump and efficient sedimentation tank have been calculated. Then, the main parameters of UV and ozone disinfection equipment in the purification process have been calculated and the selection of equipment has been made.In this paper PLC control program and HMI program have been compiled to realize the automatic control of purifying process, and the fault monitoring and displaying programs have been compiled to facilitate operators in fault diagnosis and maintenance as well. In addition, the primary standardization and reliability of the hardware and software programming have been considered for ensuring the reliable operation of the artificial seawater purification system.