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.

　　主含量是指成品中KOH的质量分数，这是确定产品质量主要的参数之一，一般要求含量大于90%。这个过程中控制好碱液的温度是关键。1.148%碱液浓度在经过一效、二效蒸发器蒸发只有，碱液浓度需要达到或大于48%，为后面进行的工序质量合格做好准备。这个过程主要是通过蒸气冷凝产生的热量用来蒸发碱液中的水分从而提高浓度，因此需要能够保证蒸气的压力和温度达到相应的要求：真空状态下可以降低碱液沸点，所以为了节约能源和提升效率，蒸发器中的真空度要尽量保持一个比较高的状态。二效蒸发器碱液真空度处于0.085~0.094MPa，温度在75~85摄氏度之间，效果是比较好的。

　　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、提高高压蒸气的压力和温度

　　1. Increase the pressure and temperature of high pressure steam

　　升膜蒸发器以高压蒸气为加热介质，可以继续提高碱液的浓度，氢氧化钾碱液温度一般在190~210摄氏度之间比较适宜。

　　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、氢气燃烧炉及熔盐系统

　　2. Hydrogen combustion furnace and molten salt system

　　浓缩制片过程需要使用熔融盐HTS为加热介质，而加热BTS是使用氢气燃烧炉来提供热源的。燃烧炉提供的热量要保证稳定，这样才能确保熔盐温度和流量的稳定，才能生成足够量的稳定热量来加热碱液，使经过浓缩器后的碱液温度达到标准要求，一般在380-400摄氏度之间。

　　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、保持系统密闭

　　3. Keep the system closed

　　为了避免碱液温度降低和发生潮解，降低其中的K0H含量，碱液在从浓缩器至片碱机的流动过程中需要尽量保持密闭状态，避免和空气进行接触。

　　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.

　　上面介绍的四种就是氢氧化钾主含量低的解决方法，通过上面的方法处理之后可以有效的提高产品的纯度。

　　The four solutions described above are the solution of low content of potassium hydroxide, which can effectively improve the purity of the product.