Analysis of four process factors can cause the stainless steel reactor to stick to the wall
Guide: The most feared use of stainless steel reactors is the sticky wall. Once the sticky wall is present when using the reactor equipment, the work of the reactor will be seriously affected. Therefore, everyone is required to operate correctly when using stainless steel reactors to avoid sticking. However, there are some process factors that make the sticky wall difficult to avoid.
There are usually four process factors that can cause the stainless steel reactor to stick to the wall:
1, raw material factors
Because the sulfate content in urea is too high, when urea is added in the late stage of the polycondensation reaction of the resin, it is equivalent to adding a curing agent to promote the rapid crosslinking of the resin into a network structure. If the treatment is not timely, the resin will be solidified in the reaction. In the kettle, therefore, standard industrial urea raw materials should be used in the production to limit the sulfate content in urea to 0.01% or less.
2, the degree of balance of operation
When the control parameters such as temperature and pressure are unstable or the fluctuation is too large, the process of resin polycondensation is uneven, and it is easy to cause sticking. Therefore, in the production operation, it should be slowly pressurized and heated. Generally, water vapor of about 0.15 MPa is passed for 2 to 3 minutes, and then the pressure is gradually raised. The lifting speed is preferably 0.1 to 0.15 MPa per minute.
3, the wall temperature difference
If the temperature of the cooling medium is too low or suddenly drops, the temperature difference between the temperature of the wall and the material is too large, causing the glue to contact the wall of the stainless steel reactor wall. Therefore, whether it is heating or cooling, it should be carried out within a reasonable temperature difference. Generally, the steam use temperature should be less than 180 °C, the temperature difference thermal shock should be less than 120 °C, and the cooling impact should be less than 90 °C. At the same time, care should be taken to determine the proper inlet and outlet temperatures of the cooling medium and to maintain a balanced operation.
4, reaction temperature and time
When the temperature of the reaction liquid is lower than 80 ° C, if ammonia chloride is used as the catalyst, the reaction rate of the ammonium chloride is fast, the pH value does not show up, and after the temperature rises, the pH value rapidly decreases, the reaction speed increases, and the polycondensation reaction is too high. Intensely causing gelation and sticking to the wall. In addition, the polycondensation reaction time is too long, the molecular weight of the resin is large, and the viscosity is too high, and the sticking phenomenon is likely to occur. Therefore, the temperature and time of the polycondensation reaction should be properly controlled during the operation, and the reaction should be terminated in time. Generally, the temperature of the reaction liquid is controlled within 0 to 95 ° C.
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