Production method for increasing nitrate removal capacity by membrane method

The invention relates to a comprehensive utilization method of an ionic membrane electrolytic saline solution waste liquid, which comprises the step of sending dechlorinated dilute brine coming out of an electrolytic tank to a membrane process denitration device for denitration The comprehensive utilization method is characterized by comprising the following steps of: pre-adjusting the pH value of a system to 3-8 by using a saline solution pH value automatic control device, exchanging the heat till the temperature of the system is 25-50 DEG C, removing free chlorine till the content of chlorine is less than or equal to 3 ppm, sending into a primary membrane separation system for primary membrane separation and controlling the primary membrane separation pressure to be not higher than 30MPa; and then sending into a secondary membrane separation system for secondary membrane separation, controlling the secondary membrane separation pressure to be not higher than 35 MPa, separating to obtain desulfurized brine and concentrated nitrate water, sending the dissolved desulfurized brine to an ionic membrane electrolytic saline solution device for reutilization and sending the concentrated nitrate water to a thermal method denitration device to prepare thenardite The invention has the beneficial effects that as the two stages of membrane separation systems are adopted, the pressure is more stable, the membrane service life is long, and the separation effect is good; the content of sodium sulfate in the separated concentrated nitrate water can reach above 90 g/l, and the content of sodium sulfate in the desulfurized brine can reach below 3 g/l

Comprehensive utilization method of ionic membrane electrolytic saline solution waste liquid

The invention belongs to the field of inorganic chemicals, particularly relates to a salt and sodium freezing crystallization and purification technology in a salt and sodium recovery process of a sewage treatment system and is suitable for salt and sodium separation treatment in a salt recovery and purification process in treatment technologies of sewage reuse, sewage zero discharge and relevant waste liquid. The technical scheme adopted by the invention is as follows: the method comprises the following steps: 1) high nitrate water firstly enters a buffer pool and is cooled by means of cooling water, and the temperature of the high nitrate water is adjusted to be 30-40 DEG C; the high nitrate water enters a first freezing crystallization tank from the buffer pool, a circulating pump is arranged on the freezing crystallization tank to be convenient for uniform stirring, the high nitrate water is subjected to freezing crystallization when reaching the top of the freezing crystallization tank so as to crystallize Na2SO4 on a condenser in the crystallization tank, and frozen water is stopped; 2) the high nitrate water is discharged into a second crystallization tank to perform a crystallization separation process, and meanwhile, after the high nitrate water is emptied, a discharge valve is closed; 3) preheated dilute saline is introduced into the crystallization tank to dissolve ice on coagulated on the crystallization tank, and after full dissolution, all middle temperature dilute saline is emptied.

Freezing crystallization and purification method used for salt and sodium separation process in sewage treatment

Process for freezing and denitriding primary brine with membrane method in polyvinyl chloride production

The invention discloses a purification device and a purification method of an organic amine desulfurizing agent in an organic amine method desulfurizing process. A regenerated desulfurizing agent solution is subjected to heat exchange through a plate heat exchanger, and is then pumped into a safety filter by a pressurizing pump to be filtered; obtained filter liquid enters a nanofiltration device; filter liquid obtained after the nanofiltration is discharged into a filter liquid groove; concentrated liquid obtained through nanofiltration is discharged into a solution storage groove; the purification device also comprises a freeze crystallization system connected with the plate heat exchanger; partial solution subjected to heat exchange is subjected to freeze crystallization to remove sodium sulphate; then, the regenerated desulfurizing agent solution subjected to the sodium sulphate removal is guided into the plate heat exchanger to be subjected to heat exchange again; next, obtained liquid and the regenerated desulfurizing agent solution in a pipeline are jointly pumped into the safety filter by the pressurizing pump to be filtered; the nanofiltration device is connected with a cleaning system and a reverse flushing system. The content of Cl and SO4 in the regenerated desulfurizing agent solution can be continuously reduced; the cleanness of the desulfurizing agent of the desulfurizing system and the stability of the desulfurizing effect can be ensured.

Purification device and purification method of organic amine desulfurizing agent in organic amine method desulfurizing process

The invention discloses a preconditioning method to strip sulfate ion of salt water with membrane process, which comprises the following steps: (1) fetching salt water from ionic membrane caustic soda system antichloration tower; adding into sodium sulfite; stripping survival free chloride; (2) adjusting pH value of the salt water at 3-7; adjusting temperature at 35-50 degc; (3) filtering with activated char to avoid chloride ion entering into barrier separation device; (4) stripping particle activated char generating by reacting activated char and free chloride with security filter; separating sulfate ion with film separating device

Pretreatment method for sulfate radical removal from salt water by membrane process

The invention discloses a method of cold separating mirabilite in salt water solution, which comprises the following steps: (1) adjusting pH value of armed salt cake solution as alkalify; (2) proceeding pre-cool in the precooling system; (3) mixing with low-temperature low-nitrate water of incorporating salt cake with lower temperature through demirabilite treatment; controlling temperature at -10-0 degc; proceeding solid-liquid separation in salt cake settler; getting ten water sodium sulfate crystal and low nitrate water; (4) lowering temperature of part low nitrate water through freezing heat exchanger; recycling as low temperature nitrate water of step (3); discharging the other part of low nitrate water as byproduct

Method freezing separating mirabilite by brine solution

The utility model provides a concentration, nano-filtration and reclamation device of the magnesium sulfate solution, used in the concentration and reclamation of the solution with 1 to 30 g magnesium sulfate per liter; the utility model is made by connecting the activated carbon filter and the magnesium sulfate solution tank; the back of the activated carbon filter is connected with a security filter; the back of the security filter is connected with a nano-filtration film device; the back of the nano-filtration film device is connected with the concentrated liquid tank; the back of the concentrated liquid tank is connected with a pre-cooling device; the back of the pre-cooling device is connected with a heat exchanger; the back of the heat exchanger is connected with a settlement device; the back of the settlement device is connected with a centrifuge; the core part of the equipment can apply the nano-filtration film device with the novel modular design; the structure is compact; the installation is easy; the applicable scope is wide; the suitable type can be chosen according to the actual needs; after the physical and chemical modification, the used nano-filtration film component has good performance of discharging the magnesium sulfate; the utility model still has the advantages that the infiltration liquid can be used as the technical water; the occupied area is small; the operating cost is low; the quantity of the generated sewage is small; and the utility model can reclaim and reuse the magnesium sulfate.

Concentration nano filtering, recovery device of magnesium sulfate solution

The utility model relates to a modified reverse osmosis membrane device used for removing sulfate radical from dilute salt solution, belonging to an ion-exchange membrane caustic soda process device. The bottom of a dilute salt solution head tank is connected with the heat exchanger via dilute salt solution transfer pump; the heat exchanger is connected with an active carbon filter; the active carbon filter is connected with a safety filter; the safety filter is connected with a modified reverse osmosis membrane filter; the concentrated solution outlet end of the modified reverse osmosis membrane filter is connected with a concentrated solution pot, the concentrated solution outlet end of the concentrated solution pot is connected with the heat exchanger, the outlet end of the heat exchanger is connected with the top end of the nitre deposit tank, the nitre deposit tank is connected with a centrifugal machine underneath, the device concentrates the sodium sulfate in the dilute salt solution by the modified reverse osmosis membrane, and then separates the sodium sulfate from the sodium chloride by freezing method to thoroughly deprive of the sodium sulfate accumulated in the chlorine alkali production to balance the sodium sulfate content in the light salt water to make the light salt water meet the electrolysis demand so as to enhance the quality and the stabilization of the light salt waters.

Li Demin Song

Papers

Pretreatment method for sulfate radical removal from salt water by membrane process

Method freezing separating mirabilite by brine solution

Concentration nano filtering, recovery device of magnesium sulfate solution

Modified reverse osmosis membrane device used for removing sulfate radical from dilute salt solution