Potassium hydroxide is a kind of strong alkali, which is often used as chemical raw material. However, if the main content of the main product fails to meet the requirements when it is used, it will also affect the subsequent use effect. How to solve the problem when the main content of the product is low? Let's take a look.
The main content refers to the content of KOH in the finished product, which is one of the main parameters to determine the quality of the product. Generally, the content is more than 90%. In this process, the key is to control the temperature of alkali liquor. 1.148% of the alkali liquor concentration needs to reach or exceed 48% after being evaporated by the first and second effect evaporators, so as to prepare for the quality of the subsequent process. In this process, the heat generated by steam condensation is used to evaporate the water in the alkali liquor, so as to improve the concentration. Therefore, it is necessary to ensure that the pressure and temperature of the steam can meet the corresponding requirements: the boiling point of the alkali liquor can be reduced in the vacuum state, so in order to save energy and improve efficiency, the vacuum degree in the evaporator should be kept as high as possible. The vacuum degree of alkali liquor in the two effect evaporator is between 0.085 ~ 0.094 MPa, and the temperature is between 75 ~ 85 ℃.
1. Increase the pressure and temperature of high pressure steam
The rising film evaporator uses high-pressure steam as the heating medium, which can continue to increase the concentration of alkali liquor. The temperature of potassium hydroxide alkali liquor is generally between 190 ℃ and 210 ℃.
2. Hydrogen combustion furnace and molten salt system
Molten salt HTS is used as heating medium in the process of concentrating and making slices, and hydrogen combustion furnace is used to provide heat source for heating BTS. The heat provided by the combustion furnace should be stable, so as to ensure the stability of the molten salt temperature and flow, and generate enough stable heat to heat the alkali liquor, so that the alkali liquor temperature after the concentrator can meet the standard requirements, generally between 380-400 ℃.
3. Keep the system closed
In order to avoid the decrease of temperature and deliquescence of lye, and reduce the content of k0h, the flow of lye from concentrator to flake caustic soda machine should be kept as closed as possible to avoid contact with air.
The four solutions described above are the solution of low content of potassium hydroxide, which can effectively improve the purity of the product.