Tang Lian Chemistry


Wall sticking phenomenon in stainless steel reactor

Stainless steel reaction vessels may exhibit wall adhesion. The main reasons for this are the following four points. Simply put, they are raw material factors, temperature difference between the reactor walls, reaction temperature and time inside the Stainless steel reactor, and the degree of operation balance.

  1. Stainless steel reactor operation balance. When the temperature, pressure, and other adhesive production process indicators are too unstable or fluctuating, the polymerization reaction is uneven, which may cause adhesion of the reactor wall. Therefore, in production, it is necessary to slowly increase the excitation and temperature. Inject approximately 0.15MPa into the steam and hold for 2-3 minutes, then slowly increase the pressure. Increase speed every minute. 0.1~0.15MPa.
  2. Reaction temperature and time of stainless steel reaction kettle. When the temperature of the reaction solution is lower than 80 ° C, ammonia chloride is used as the catalyst. Because the reaction speed of ammonia chloride is fast, the pH value cannot be given. When the temperature rises, the pH value will drop quickly, the reaction speed will be accelerated, and the condensation force is too strong to cause gel and mucous membrane.
  3. The starting material factor for stainless steel reaction is due to the high sulfate content in urea. When the condensation resin in the stainless steel reactor participates in urea, it is equivalent to participating in the curing agent, promoting the rapid binding of the resin in the network structure. If not handled in a timely manner, the resin will be fixed in the reactor. During the production process, standard industrial urea materials should be selected to limit the sulfuric acid content in urea to below 0.0001.
  4. The temperature difference between the stainless steel reactor boiler wall, low or sudden drop in cooling medium temperature, and high temperature between the reactor wall and the material result in contact between the adhesive and the boiler wall, causing the reactor to adhere to the wall. Therefore, heating and cooling are necessary within a reasonable temperature range. Usually, the steaming temperature needs to be less than 180 ° C, the temperature shock needs to be less than 120 ° C, and the cooling shock of the stainless steel reactor should be less than 90 ° C. To maintain operational balance.

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