Sodium bisulfite is a weak reducing agent and cannot be used as a strong reducing substance. In the printing and dyeing industry, as an oxygen absorber and bleaching agent, it is used in the cooking of various cotton fabrics, which can improve the whiteness of the boiled refining material. So how is sodium bisulfite produced?
1. The raw material liquid sulfur enters the refined sulfur pool, which is a square container with 12 groups of heating coils, which are heated under 0.3-0.4MPa steam to show a liquid state with good fluidity (the melting temperature of sulfur is 118. 9 degrees), the temperature of the fine sulfur tank is controlled in the range of 135-145 degrees;
2. Incineration of liquid sulfur: the incineration of liquid sulfur is carried out in the incineration furnace, the incineration sulfur furnace is a garden-type horizontal furnace, there are three partition walls in the middle, lined with refractory bricks, insulation bricks, the air is centrifuged from the front of the furnace to enter, the liquid sulfur is pressurized by the sulfur pump to about 0.5MPa, and the high-pressure sulfur spray gun is centrifuged into the furnace, forming a fog to fully mix with the air, burning, generating sulfur dioxide and releasing heat, so that the furnace gas temperature rises to nearly 900 °C to leave the incineration furnace to remove the waste heat boiler;
3. Waste heat utilization: high temperature furnace gas into the waste heat boiler, sulfur dioxide furnace gas flows out through the tube, outside the tube is furnace water, furnace water is heated and evaporated into steam, into the steam drum for soda separation, water returns to the furnace steam under the action of 2.5MPa to leave the waste heat boiler;
4. Cooling of furnace gas: furnace gas < 300 °C to leave the waste heat boiler into secondary cooling, through the lined glass tube drain cooler, further cooled to 60 °C into the water washing tower, water wash to remove impurities after entering the mist eliminator;
5. Absorption of sulfur dioxide: the furnace gas through cooling and mist removal enters three series absorption towers, sprays 17%-22% alkali solution in the tower, generates sodium bisulfite in the tower, when the PH value reaches 3.7-4.5, the system is transferred out of the system into the finished filter, the finished filter is a microporous filter tank made of polytetrafluoride, the solution is in and out, into the underground tank, the finished product tank is injected into the finished product tank as sodium bisulfite, the absorption rate of sulfur dioxide in the furnace gas is absorbed by the 1# tower, and the remaining exhaust gas is discharged into the air through the exhaust chimney. Complete the entire production process.
The above is the production process of sodium bisulfite, sodium bisulfite will emit harmful gases in the production process, so the staff should wear protective equipment and standardize operation to avoid danger.