Trichloroisocyanuric acid(TCCA) Process description
(1) Salt-forming process
Start the liquid alkali feeding pump and pump 32% liquid alkali in the storage tank into the liquid alkali metering tank. When the metering tank is full, close the feed valve and add a certain amount of water to the ingredient water metering tank. The ingredient water metering tank and the liquid alkali metering tank are equipped with overflow pipes; close the discharge valve of the ingredient tank, add the water in the ingredient water metering tank, and then add the measured liquid alkali, start stirring, and add cyanuric acid into the ingredient tank to make the materials react at room temperature. When the cyanuric acid in the tank is completely dissolved, the product is trisodium salt. Start the dosing pump and pump the trisodium salt into the filter tank to filter out insoluble matter, and then use a pump to pump the filtered trisodium salt solution into the trisodium salt temporary storage tank, and then use the pump to pump it into the trisodium salt cooling tank. The cooling tank is equipped with an internal coil and refrigerated brine is passed through for cooling. Then the trisodium salt is pumped into the chlorination process through the second suction circulation pump of the cooling tank.
(2) Chlorination process
Start the secondary suction circulation pump of cooling tank, turn on the trisodium salt feed regulating valve, send the solution in the trisodium salt cooling tank to the secondary absorption tower of the chlorinated tail gas, and then overflow to the primary absorption tower of the chlorinated tail gas, absorb the chlorine in the chlorinated tail gas and overflow into the chlorination reactor. The chlorination reactor is equipped with an internal coil, and frozen brine is passed to cool it down, and then overflow to the chlorination reactor for chlorination reaction. Start the circulation pump and fan of absorption tower; close the bottom discharge valve of the chlorination reactor and add tap water to the reactor, start stirring, open the chlorine valve, control the chlorine rotor flowmeter, and pass chlorine into the chlorination reactor at a certain speed. When the pH value of the aqueous solution in the reactor drops to a certain value, turn on the trisodium salt rotor flowmeter, continuously feed the chlorination reactor at a certain flow rate, control the chlorine flow rate, and pass chlorine according to a certain sodium-chlorine ratio; during the chlorination process, cooling brine is passed through the jacket and cooling coil of the chlorination reactor, and the brine control valve is adjusted to keep the reaction temperature of the chlorination reactor stable.
(3) Separation process
The trichloroisocyanuric acid reaction liquid in the chlorination reactor flows into the chlorination material collection tank through the overflow pipe, and is pumped into the trichloroisocyanuric acid centrifugal high-level tank by the chlorination material pump, and flows into the centrifuge for solid-liquid separation to obtain trichloroisocyanuric acid wet product.
The wet product produced by centrifugation is sent to the fluidized bed for drying through the centrifuge unloading belt, and the mother liquor produced flows into the trichloroisocyanuric acid mother liquor tank by gravity, and is sent to the dechlorination process through the trichloroisocyanuric acid mother liquor delivery pump.
(4) Drying, granulation, and packaging
The wet trichloroisocyanuric acid is sent to the crasher through the material distribution belt, and after being broken, it falls into the feed port of the liquid-bed dryer and is dried by full contact with hot air. An air flow conveying pipeline is set at the outlet of the liquid-bed to collect the dried trichloroisocyanuric acid through a cyclone separator, and part of the dry material is packaged; part of the dry material enters the granulator through the granulation and material distribution screw and is granulated by a dry roller granulator. After granulation, it is screened through a first-stage vibrating screen. The powder produced by the vibrating screen is returned to the granulator through an air delivery pipeline. The large and small granules produced are sent to the second-stage vibrating screen and the third-stage vibrating screen through a mixing screw for further separation. The large granules produced enter the large granule silo, and the small granules enter the small granule silo. After packaging, they are stored.
(5) Mother liquor dechlorination and neutralization
The main components of the centrifugal mother liquor from the trichloro workshop of the mother liquor tank include sodium chloride and trichloroisocyanuric acid. The mother liquor is pumped to the dechlorination reactor, and 31% hydrochloric acid is introduced into the bottom of the reactor. The pH value in the reactor is adjusted to maintain at 1-1.5. Under stirring and compressed air stripping, the effective chlorine in the mother liquor is reduced to chlorine gas under acidic conditions and removed. The dechlorination reactor returns the removed gaseous chlorine gas to the chlorination liquid absorption system through the chlorination tail gas absorption system; at this time, a small amount of chlorine gas will still be dissolved in the mother liquor. Compressed air is continued to be used to separate the tail chlorine from the liquid phase. As the chlorine gas is removed from the mother liquor, cyanuric acid is precipitated from the mother liquor. After the chlorination is completed, sodium hydroxide solution is added for neutralization operation, so that all the hydrochloric acid in the mother liquor is converted into sodium chloride, and then the mother liquor is pumped to the suction filtration tank.
(5.1) Mother liquor separation
The dechlorination mother liquor is pumped into the suction filtration tank for solid-liquid separation. The filter cake is mainly cyanuric acid, which enters the trichloro recovery cyanuric acid pulping tank for pulping, and then returns to the batching process for recovery. The mother liquor produced in the filtration tank flows by gravity into the mother liquor tank after the trichlorine recovers cyanuric acid, and is pumped into the trichlorine mother liquor pool. The mother liquor settles in the trichlorine mother liquor pool to further remove cyanuric acid, and the clear liquid filtered by the trichlorine plate and frame filter press enters the MVR evaporation system.
(5.2) Mother liquor evaporation and centrifugation
The sodium chloride solution is evaporated and concentrated by the MVR evaporation system to precipitate sodium chloride solid particles, and then the sodium chloride wet product is separated from the concentrated mother liquor by solid-liquid separation through a centrifuge. The separated mother liquor returns to the evaporation system for further concentration. The generated condensed water enters the trichlorine water purification pool and returns to the trichlorine device through the trichlorine circulating water pump as feed water for reuse.
(5.3) Packaging
The moisture content of the wet sodium chloride separated by centrifuged is within 2%, and it is packaged and stored after centrifuged.
