| High salt wastewater from coal chemical industry is the final discharge wastewater of coal chemical plant.Its discharge quantity is large and its water quality is complex.In recent years,the water treatment technology and chemical agent technology have been obviously upgraded,and the equipment pipes are continuously updated.To a large extent,the recovery rate of water used in coal chemical systems has been greatly improved.But even so,water use and water displacement in coal chemical systems are still very large,which not only wastes a large amount of water resources,but also causes great pollution to the water ecology.Seriously constraining the sustainable development of the coal chemical industry.The present situation of water use and drainage in these coal chemical industries has aroused the concern and concern of the industry.Therefore,it is of great practical value to study how to realize "zero liquid discharge"?resource utilization?of high-salt wastewater from coal chemical industry.Coal chemical high-salt wastewater is a kind of industrial wastewater with "high organic matter,high salinity,high hardness and high silicon content",which is characterized by complex composition and high pollutant content.The recovery rate of water system is not high when conventional industrial reuse water treatment process is adopted.The produced water quality is unstable,and the drainage water quality can not guarantee the discharge standard,and the water resources can not be maximized.In this paper,a large coal olefin project in Yulin,northern Shaanxi Province,is used as raw water,and the main components of raw water discharged by the former system are analyzed.This paper expounds the division of new high salt wastewater treatment process,and finds out a stable and efficient "zero liquid discharge" process route by means of experiment and technical research.In this paper,the drainage of a large coal-to-olefins project in Yulin,northern Shaanxi Province was used as raw water,the characteristics of water quality and main pollution factors were analyzed,the principle of pollutant removal was expounded,and it designs a stable and efficient“zero liquid discharge”process route for wastewater.The main research on technological units of high valence scaling ion removal units,COD removal devices,and soluble fouling ions were subjected to experimental studies to determine relevant technical parameters and provide technical basis for zero liquid discharge projects for high-salt wastewater.The test results show that the optimum p H of unconventional scaling ion controlled by the coagulation experiment of the drug is 11.5,and the hardness removal rate is over 90%.A combination of strong acid cationic resin and chelating resin was used to further soften the high salt water after softening,with the equilibrium concentration when Ca2+and Mg2+are all absorbed,and the removal rate of hardness ions after treatment with a first sodium ion exchanger can reach over 90%,after the secondary chelate resin exchanger hardness ion concentration can reach0.01mg/l or less.In particular,the helium and cesium ions that affect the operation of the posterior membrane can be effectively controlled.The COD value in concentrated brine can be controlled below 40mg/l by continuous pulsed activated carbon device and COD-removal resin.Sodium chloride and sodium sulfate can be basically separated by Using nanofiltration for salt separation,and the amount of NaCl recovered in nanofiltration water is over 90%of the total influent NaCl.Relying on a project's multi-effect evaporation process,the evaporation treatment of high salt wastewater can provide technical basis for the utilization of high salt wastewater.At the same time,through a self-made filter press of a certain enterprise,the crystallization test of the mother liquor after multi-effect evaporation can be carried out,which can realize the pressure filtration of salt,and finally achieved the utilization of high salt wastewater in coal chemical industry. |
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