35- The feather leaf separator is used for the separation of secondary steam in the dilute acid concentration and evaporation process of sulfuric acid/phosphoric acid/nitric acid mixed acid catalytic systems
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This post was last edited by luoli519 on 2022-11-30 at 20:21. Currently, catalytic reaction systems using mixed binary or ternary concentrated acids such as sulfuric acid/phosphoric acid/nitric acid, especially in processes like cyclodehydration and hydroxymethylation dehydration, generate considerable amounts of water as a by-product, which gradually dilutes the original concentrated acid mixture, resulting in large quantities of mixed binary or ternary diluted acids. Many companies directly neutralize the mixed dilute acid emitted by the equipment with ammonia to obtain an ammonium salt solution, and then subject this dilute ammonium salt solution to multi-stage evaporation, concentration, and crystallization to produce solid ammonium salts for sale. For example, the dilute acid emitted by the caprolactam plant is neutralized with ammonia, and then solid ammonium sulfate by-product is obtained through multi-effect evaporation crystallization for external sale. However, due to limited demand for ammonium sulfate, its price is low. In some foreign units and process packages, the diluted mixed acid is directly dehydrated through an evaporation concentration system to produce a highly concentrated regenerated mixed acid, which is then blended with a smaller amount of nicotinic acid before being reintroduced into the reaction unit for reuse. Both of the aforementioned methods for treating mixed dilute acids involve evaporation and concentration devices to carry out evaporation and dehydration; this either results in solid ammonium salts that can be sold, or in high-concentration regenerated mixed acids that can be reused in the process ； Solving the problem of removing the acid droplets and salt droplets carried by the secondary steam is a challenge that all parties must face together. Friends, please refer to the evaporation, dehydration, and concentration systems they have in use at home, and share information on the uses of the secondary steam generated there as well as the techniques used for removing foam from this steam, so that we can all benefit from it.
This post was last edited by luoli519 on 2022-11-30 at 20:21. The secondary steam demisting for the 4 multi-effect evaporation crystallizers with a diameter of 7600 mm, which are used for evaporating and concentrating the dilute sulfuric acid produced as a by-product in the caprolactam plants of Dutch mining companies, utilizes baffle separation technology for its internal components.
This post was last edited by luoli519 on 2022-11-30 at 20:22. The fan-shaped blade separation internals offer great operational flexibility; they are not prone to blockage of the flow channels due to the accumulation of precipitated crystals. They provide high efficiency and stable operation, with particularly low operating pressure drops, making them especially suitable for vacuum evaporation of saline and alkaline solutions.
It is understood that many evaporator manufacturers in the East China region are still using wire mesh demisters. When such traditional and simple demisters are used in vacuum evaporation crystallization systems for saline solutions, they are prone to being clogged and corroded by the crystals that form in the gas phase, which leads to an increasing operating pressure drop. This in turn requires higher reactor temperatures and more thermal steam, making it difficult to maintain stable continuous production.
This post was last edited by luoli519 on 2022-11-30 20:22. The demister for the concentrated evaporation of dilute sulfuric and phosphoric acid mixtures in Global Tech systems also uses the baffle separation internals provided by NOVEL design.
This post was last edited by luoli519 on 2022-11-30 20:22. The concentrated evaporation process for mixed sulfuric acid and phosphoric acid acids used by APAIK China also involves considering the use of vane separation internals to upgrade its existing wire mesh demisters.
The last edit to this post was made by luoli519 on 2023-10-3 at 14:24. A process engineer from APAIK China told NOVEL that the secondary steam generated by the evaporator is in large quantities and flows at high speeds; its temperature is around 100°C. The original wire mesh demisting elements had a short service life, suffered from severe wire breaks, exhibited unstable demisting efficiency, and the secondary steam contained high levels of acid. It is necessary to upgrade the traditional mesh demisting method by using a high-efficiency dynamic vane demister that offers higher separation efficiency, greater operational flexibility, and more stable operation.
This post was last edited by luoli519 on 2022-11-30 at 20:23. For information and drawings related to the secondary steam vane separators used in NOVEL Company’s evaporation concentrators, please visit www.novelseparationtech.com.
This post was last edited by luoli519 on 2022-11-30 at 20:23. Regarding the multi-effect evaporation crystallizer used for dilute sulfuric acid in caprolactam plants, which features a fan-blade type separation internal component, refer to the discussions and explanations in the post at http://bbs.hcbbs.com/thread-1565169-1-1.html.
This post was last edited by luoli519 on 2022-11-30 at 20:23. Many domestic evaporator manufacturers do not use vane-type separation components; instead, they continue to rely on traditional, simple, and inefficient mesh screens. The structure determines the performance, and many problems arise during actual operation.
This post was last edited by luoli519 on 2022-11-30 at 20:24. Many domestic evaporator manufacturers fail to use vane-type separation components and continue to rely on traditional, simple, and inefficient wire meshes; an important reason for this is misleading experience. The size of the evaporator shell is determined by the evaporation vapor velocity. Manufacturing companies, without considering any consequences, simply lay wire mesh sheets on the cross-sectional surface of the evaporator cylinder; some companies cover the entire cross-sectional area, while others cover only a portion of it. In fact, the maximum flow velocity of the gas through the mesh is lower than that through the cross-section of the hollow evaporator cylinder, which requires the flow area of the mesh block to be larger than the cross-sectional area. The problem is that the framework of the mesh blocks installed across the cross-section of the evaporator cylinder accounts for several percentage points; even when they are installed throughout, the available area is still insufficient. Moreover, some companies opt to install the mesh only in certain areas