TRICHLOROISOCYANURIC ACID(TCCA)

Add water, cyanuric acid, and 1240kg of calcium carbonate to the batching tank in proportion, stir under the room temperature for 20 minutes, and transfer to the batching storage tank through the pump

The process flow of sodium dichloroisocyanurate

1. Mix materials

Add water, cyanuric acid, and 1240kg of calcium carbonate to the batching tank in proportion, stir under the room temperature for 20 minutes, and transfer to the batching storage tank through the pump. Part of the suspension in the batching storage tank is pumped into the secondary absorption tower as chlorinated tail gas absorption liquid through the circulation pump, and another part is pumped into the chlorination reactor through the batching storage tank pump.

Add water and calcium hydroxide to the pulping tank in proportion to make a 20% calcium hydroxide suspension, and then pump it into the dechlorination neutralization process through the pulping tank pump.

Add sodium carbonate to the soda ash silo with a crane, measure it through the metering auger, send it to the feeder, and send it to the alkali silo above the mixer through compressed air.

2. Chlorination 

Operate the chlorination reactor for stirring, pump the materials in the batching storage tank, start the internal coil cooling system, and continuously passing chlorine from the bottom of the reactor (below the raw material liquid level) into the chlorination reactor through a dedicated chlorine pipeline. Control the chlorine pressure at 0.15-0.25MPaG, the pressure of the chlorine buffer tank is not less than 0.15Mpa, the temperature of the chlorination reactor is controlled at 25-35℃ (frozen brine temperature control), and the pressure is slightly negative pressure; the chlorination reaction is 4-5h, and determine the end of reaction according to the pH value of the feed liquid in the reactor. Stop passing chlorine after the material is chlorinated to the end point, transfer the suspension after the reaction to the discharge tank, and then transfer it to the reaction material storage tank through the discharge tank feed pump. The excess chlorine introduced into the chlorination reactor enters the two-stage feed liquid absorption tower through the top pipeline of the chlorination reactor, and is absorbed by cyanuric acid and calcium carbonate solution. The unabsorbed chlorine finally enters the third and fourth alkali solution absorption systems. After the reaction liquid in the chlorination reactor is transferred out, it is pumped into the next batch through the batching storage tank and enters the reactor.

3. Solid-liquid separation (continuous production)

The chlorinated clinker in the reaction material storage tank is sent to the rotary drum filter for solid-liquid separation through the reaction material delivery pump. The solid produced is the dichloroisocyanuric acid wet product, which is sent to the dichloro acid silo through the dichloro belt conveyor. The mother liquor produced by the rotary drum filtration flows from the dichloro gas-liquid separation tank into the dichloro mother liquor tank by gravity, and is sent to the dechlorination neutralization process through the dichloro mother liquor delivery pump.

4.Neutralization process (continuous production)

The washed dichloroisocyanuric acid wet product is sampled to measure the effective chlorine content, and is sent to the mixer through the dichloro acid metering belt. At the same time, a certain proportion of sodium carbonate is continuously added through the soda metering belt for neutralization reaction. The mixed material is sent to the fluidized bed drying system through the mixer conveyor belt.

5. Drying, granulation, and screening (continuous production)

The wet sodium dichloroisocyanurate is sent to the fluidized bed dryer by a belt conveyor. The airflow temperature at the fluidized bed feed port is between 130 and 170°C to dry the material to obtain dichloroisocyanuric acid powder. After drying, the dry product is collected in a cyclone separator through an air delivery pipe, and part of the dry material is packaged; part of the dry material directly enters the granulation process and is granulated using a dry roller granulator. After granulation, the particle size is graded by a vibrating screen and then flows into silos of different specifications. The product is then loaded into the silo and weighed before being stored.

6. Mother liquor treatment

The mother liquor treatment uses the centrifugal mother liquor containing calcium chloride produced by sodium dichloroisocyanurate as a raw material to produce calcium chloride, and recovers cyanuric acid and concentrates calcium chloride through dechlorination, neutralization, evaporation, drying and other processes.

a Dechlorination neutralization

The mother liquor from the dichlorine mother liquor tank is pumped into the dechlorination overflow kettle. The mother liquor enters from the bottom of the dechlorination overflow kettle. At the same time, 31% hydrochloric acid is added in proportion. The dichloroisocyanuric acid in the mother liquor reacts with hydrochloric acid to produce chlorine and cyanuric acid. A compressed air stripping pipeline is set at the bottom of the overflow kettle. The chlorine in the mother liquor is discharged into the chlorination tail gas absorption tower through the pipeline at the top of the overflow kettle. The overflowed mother liquor enters the dechlorination neutralization kettle. A compressed air stripping pipeline is set at the bottom of the dechlorination neutralization kettle to further remove the chlorine in the mother liquor. After the chlorination is completed, calcium hydroxide slurry is added for neutralization operation, so that all the hydrochloric acid in the mother liquor is converted into calcium chloride.

b Mother liquor separation (intermittent production)

After the neutralization kettle is completed, the mother liquor is pumped into the suction filter tank by the dechlorination feed pump to separate the cyanuric acid in the mother liquor. The generated cyanuric acid is sent to the dichlorine recovery cyanuric acid pulping tank for pulping, and then returned to the batching tank for recovery. The mother liquor after cyanuric acid recovery produced by the filtration tank enters the mother liquor tank after cyanuric acid recovery, and then is sent to the dichloro mother liquor tank for sedimentation by the mother liquor after cyanuric acid recovery pump. The concentrated liquid produced is sent to the filter press by the dichloro filter press pump to filter out cyanuric acid. The mother liquor produced is calcium chloride solution, which is sent to the calcium chloride three-effect evaporation system.

c Calcium chloride evaporation

The calcium chloride solution is concentrated by the three-effect evaporation system. The calcium chloride solution is first pumped to the calcium liquid preheater to be heated to 40℃~45℃, and then indirectly heated to about 150℃ by the three-effect evaporator and the countercurrent steam. When the calcium chloride concentration is close to 68%, it can enter the fluidized bed drying. The steam condensate produced by the three-effect evaporation and the evaporated condensate are cooled and then enter the clear water tank for reuse as production water. When the concentration of calcium chloride solution reaches 30%, it can be directly pumped into the calcium liquid tank for temporary storage and sale.

d Calcium chloride drying

The nearly 68% calcium chloride solution from the evaporation process is cooled in a crystallizer and solidified into a powdery or flake calcium chloride wet product, which is then sent to a fluidized bed dryer for drying. The dried calcium chloride is sent to a cooling drum via a closed belt conveyor for cooling and packaging before being stored. The calcium chloride drying system uses hot air drying. The hot air heat exchanger uses heat transfer oil as the heat source. The air and heat transfer oil are indirectly exchanged, and the temperature is raised to 150°C before being sent to the fluidized bed dryer. The dust-containing exhaust gas generated during the drying process is treated by a bag filter and sent to a dust-containing exhaust gas spray tower.