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Factors causing wall sticking of stainless steel reaction kettle


Release time:

2019-04-02

Many problems have been found in the production of stainless steel reactor wall sticking. Among them, stainless steel reactor wall sticking is a common phenomenon. The specific analysis of the factors causing stainless steel reactor wall sticking is as follows: First, the raw material factor is due to the high sulfate content in urea. When urea is added at the later stage of resin polycondensation reaction, it is equivalent to adding curing agent to promote rapid crosslinking of resin into a network structure. If the treatment is not timely, the resin will be solidified in the reaction kettle, therefore, in the production should be used in the standard industrial urea raw materials, so that the sulfate content in urea is limited to less than 0.01%. Second

The factors that cause the stainless steel reaction kettle to stick to the wall are found in the production of the reaction kettle. Among them, the stainless steel reaction kettle stick to the wall is a frequent phenomenon. The specific analysis of the factors that cause the stainless steel reaction kettle to stick to the wall is as follows:
First, the raw material factors due to the high content of sulfate in urea, when the resin polycondensation reaction in the latter part of the urea, it is equivalent to adding a curing agent, to promote the rapid cross-linking of the resin into a network structure, if not treated in time, it will make the resin solidified in the reactor, therefore, in the production should be selected standard industrial urea raw materials, so that the sulfate content in urea is limited to less than 0.01.
Second, the degree of balance of operation When the temperature, pressure and other glue making process indicators are unstable or fluctuate too much, the resin polycondensation reaction process is uneven, which is easy to cause wall sticking. Therefore, in the production operation, it should be slowly pressurized and heated. Generally, water vapor of about 0.15Mpa is introduced for 2~3min, and then the pressure is slowly raised and the temperature rises. The lifting speed is 0.1 ~ 0.15Mpa per minute.
Third, the kettle wall temperature difference cooling medium temperature is too low or suddenly cooled, so that the kettle wall temperature and material temperature difference is too large, resulting in contact with stainless steel reaction kettle kettle wall glue stick wall. Therefore, both heating and cooling should be carried out within a reasonable temperature range. Generally, the steam use temperature should be less than 180 ℃, the temperature difference thermal shock should be less than 120 ℃, and the cooling shock should be less than 90 ℃. At the same time, attention should be paid to determine the appropriate cooling medium inlet and outlet temperature, to maintain a balanced operation.
Fourth, the reaction temperature and time When the reaction liquid temperature is lower than 80 ℃, if ammonia chloride is used as a catalyst, the pH value cannot be displayed due to the fast reaction speed of ammonia chloride. After the temperature rises, the pH value drops rapidly, the reaction speed is accelerated, and the polycondensation reaction is too intense to cause gel and stick 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 wall sticking phenomenon is easy to occur. Therefore, the temperature and time of the polycondensation reaction should be correctly controlled during operation, and the reaction should be terminated in time. Generally, the temperature of the reaction liquid should be controlled within ~ 95 ℃.