The issue of acid dissolution temperature increase during the preparation of secondary seeds in titanium dioxide production
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First, thank you all, experts! In the acid dissolution process for preparing secondary seeds at our factory, it is required to raise the temperature to 102 degrees Celsius, with a heating rate of 1 degree per minute. However, the two existing reactors can meet the requirements up to 95°C; beyond that temperature, the rate of temperature increase becomes very slow, with only 1°C increase per twenty to thirty minutes. I don’t know what the reason is
This post was last edited by *nht1 on 2017-3-18 21:34: Low steam temperature
7kg of pressure, with a temperature of 270
Low-pressure steam: Pressure 0.7, Temperature 270℃
Is it related to altitude? Is the acid dissolution equipment operated at atmospheric pressure or positive pressure?
The temperature and pressure are both sufficient; please explain how heating is carried out, and in what way is steam used to raise the temperature of the material
Try reducing the temperature of the 0.7Mpa steam to 165–170°C (the saturation temperature of 0.7Mpa steam is 164.95°C). PS: In the titanium dioxide production process, except for the gas-powder stage (medium-temperature and medium-pressure steam) which requires superheated steam, low-pressure saturated steam is used for all other indirect and direct heat exchange processes. (Vacuum crystallization can involve a slight superheat.) When saturated steam changes from the vapor phase to the liquid phase, it releases a large amount of heat (sensible heat), which facilitates heat exchange. During the heat exchange process, superheated steam remains in the gaseous state even after its temperature drops slightly, releasing a small amount of heat (latent heat). This is also why saturated steam is commonly used as the heat source in heat exchangers.
The 10th floor is for experts. You didn’t make it clear whether this speed has never been reached or will not be reached in the near future Also, at higher altitudes, 102 degrees cannot be reached. There are a few more points: 1. You will find that even if the required heating rate is not met, the seed crystals are still fine ； The key to calcining seed crystals is alkali dissolution. 2. Where does 102 degrees Celsius come from? I remember it should be at a gentle boil ； During the configuration of the DCS back then, the condition in this area was continuous heating; if the temperature change rate was less than the set value, it was considered as gentle boiling.