How to treat extraction exhaust gases to reduce fluoride content
Thread Content
Generally, a Wen-Tower-Tower washing unit is used to remove fluorine from extraction exhaust gases, but in practice it is difficult to bring the fluoride content to the required level. Please share your experiences in this regard.
The exhaust gas washing process scheme for the phosphate plant in our facility adopts a configuration consisting of a Venturi washer along with two cyclone spray scrubbers. The exhaust gases are ultimately released into the atmosphere through a 45m tall chimney. The process is the same as what I mentioned to you; as long as its operational efficiency is maintained, the fluoride levels can still remain within acceptable limits.
Whether the exhaust emissions meet the standards depends mainly on the performance of the exhaust gas washing system; if the venturi and the two exhaust gas washing towers are operating properly, then the emissions will generally meet the required standards； The key issue is that the exhaust gas washing system tends to get clogged, requiring significant cleaning efforts; as a result, it is difficult to achieve the desired level of exhaust gas purification ； To ensure that exhaust emissions meet the required standards, I believe the following steps are essential: 1. Strengthen the management of the cleaning process for the exhaust gas washing system, and establish an effective management system ； 2. Ensure the water quality in the exhaust gas washing system, reduce the residence time of the circulating water in this system, and maintain its proper operation ；
The Venturi tube generally poses no issues; the main challenge lies in the washing of the two subsequent empty towers, where it is essential to ensure an appropriate gas-liquid ratio and spray density. Additionally, staggered spraying is also crucial.
The simplest method is to wash with lime milk, but it needs to be cleaned frequently
1. Ensure the quality of circulating water. 2. Maintain the temperature of circulating water. 3. Control the temperature of the extraction reaction properly. 4. Operate with care and check the atomization condition of the nozzles
Could you explain in detail how to add it on the 5th floor?
Actually, you can also insert the sulfuric acid addition pipe below the liquid level in the reaction mixture; this way, the fluoride content in the exhaust gases exiting the reaction tank can be reduced to some extent, but the fluoride content in the liquid phase will increase.
It is possible to add large-capacity tail-washing circulation tanks, which enable the washing water to be cooled and to recover its absorption capacity more quickly. After the modifications, our company’s absorption rate of fluorine-containing waste gases has **increased**. At present, it is necessary to clean the circulation tanks regularly.