Desulfurization tower with liquid present

A swirl plate can be used as a substitute. Additionally, it is necessary to calculate the flow rate and liquid-to-gas ratio; exceeding these limits can also lead to the presence of liquid

Many plants experience this phenomenon to some extent; as a result, some add defoaming devices to the desulfurization tower (screens or swirl plates are all viable options, but issues such as clogging and pressure loss must be taken into consideration). Others increase the height of the space at the top of the tower. I believe that from a process perspective, the key is to properly control the circulation rate and the vapor-liquid ratio, and devices like distributors on the top trays need to be cleaned regularly.

We install a gas-water separator directly after the desulfurization tower to recover the desulfurization liquid.

You can try a swirl defoaming plate or a herringbone demister.

First, high-efficiency membrane separators can be used to completely recover the mist from the gas； Also, the gas circulation volume needs to be controlled and should not be too large.

Get a different desulfurization tower~~~ That one shouldn’t be expensive…… something that a factory can afford

Just use the previous gas-liquid separation tank, that would work, right?

Usually, a gas-liquid separator is added at the back

There is also a gas-liquid separation tank behind our factory; after separation, the liquid flows back to the rich liquid tank

Liquid entrainment in desulfurization towers generally needs to be addressed through equipment design and process management. (Wire mesh mist eliminators are not suitable for use in desulfurization systems, as these systems contain high levels of elemental sulfur; therefore, mist eliminators made of plates should work effectively.) The space velocity in desulfurization towers should not be set too high, as this can also lead to liquid entrainment； In normal process management, the sulfur content in the lean liquid should not be too high; the amount of additives added must be appropriate. If there is a slight issue with liquid carryover, increasing the dosage of PDS can be tried as a solution.

Currently, the demisters used in towers both domestically and internationally include types such as wire mesh demisters/fiber-based demisters, baffle demisters, swirl plate demisters, and high-efficiency vane-type gas-liquid demisting and separation devices. Screen-type demisters/fiber-type demisters offer good demisting performance, but solid particles that can be carried by air currents, gels, and salts and alkalis dissolved in liquid droplets can precipitate and crystallize, blocking the flow channels. This leads to a rapid decline in separation efficiency and an increase in operating pressure drop. It is necessary to replace and maintain the internal components regularly, resulting in high operational and maintenance costs. Baffle demisters and swirl plate demisters offer satisfactory anti-clogging performance and operating pressure drops, but their demisting efficiency is lower than that of mesh-type or fiber-type demisters. The feather-leaf type high-efficiency gas-liquid demisting and defogging separator represents an upgrade over screen-type demisters/fiber-type demisters, baffle demisters, and swirl plate demisters; by combining the advantages of these various types while avoiding their shortcomings, it has been widely used and promoted in recent years in new process packages and projects both domestically and internationally, as well as in the renovation of existing installations. Here is a comparative introduction to these types of defoamers. The wire mesh demister belongs to the traditional barrier-type demisting internal component technology; since its use began in the early 20th century, there have been few technological improvements. It primarily relies on the pores formed by the interweaving and \"bridging\" of screen fiber filaments to block and intercept liquid droplets and mists within a certain size range, thereby achieving separation. However, the pores formed by the interbridging of fiber filaments are distributed in a small Gaussian pattern; while small-sized liquid droplets and mist particles are trapped and separated by the smaller pore sizes, larger-sized droplets are able to pass through the larger pores and escape. Therefore, traditional perforated baffle-type demisters find it difficult to achieve highly efficient separation of liquid droplets and mists of specified sizes. In addition, the flow channels of screen-type demisters are prone to being blocked by solid particles and gels that can be carried along by air currents, which leads to a rapid decline in separation efficiency, high operating pressure drops, limited operational flexibility, and the risk of metal fiber wires being eroded and broken. As a result, it is necessary to regularly maintain and replace the internal components of screen demisters, resulting in high costs for operation and maintenance. However, due to limitations in the understanding of demisting separation technologies, screen-type demisters are widely used across various industries. They are not suitable for applications with high liquid content in the gas stream and unstable operating conditions, nor for use in removing mist from gas streams that contain solid particles, gels, or liquid droplets. To address the shortcomings of screen-type demisters, such as frequent clogging, short operating cycles, and difficulties in operation and maintenance when dealing with air streams containing solid particles, gels, and liquid droplets, baffle-type demisters and swirl plate demisters were introduced abroad in the mid-20th century. Baffle plates, also known as Chevron plates, have a lower separation efficiency compared to screen-type separators. However, their advantages include resistance to clogging by solid particles, lower pressure drop, longer operational life, lower operating and maintenance costs, and no need to replace internal components. The swirl plate demister is based on the Chevron baffle; through simple modifications, it replaces the multiple momentum changes in the flow channels of the original baffle with a single large swirl, making its production and installation simpler and more convenient ； However, the separation efficiency did not improve substantially. Baffle and swirl plate demisters do not escape the control mechanism based on gravity separation; as a result, the airflow still flows vertically, with gravity acting downward to separate the gas phase. Furthermore, due to the lack of sufficiently accurate fluid dynamics modeling for separation processes at that time, these separation techniques relied on basic empirical designs; there was a lack of adequate model data to guide the scaling up of fluid conditions, leading to continuous issues with such empirical scaling approaches. Abroad, it is basically used only for rough separation in the flue gas lime-based desulfurization process of FGD power plants ； For applications requiring quantitative and efficient separation, baffle demisters and swirl plate demisters are not recommended. The vane-type demister separator, which comes after the baffle and swirl plate types, aims primarily to maintain the advantages of those devices while continuously narrowing the gap in separation efficiency compared to the barrier-type demisters. The main focus is on continuously improving the dynamics of its internal microfluidic channels, in order to achieve efficient and stable quantitative separation, a wider range of operational flexibility, and reduced space requirements for installation. At present, the fifth-generation technology at the highest technical level is the feather-leaf type high-efficiency gas-liquid demisting and defoaming separator. Its secondary microchannels and short-path structures force the airflow to flow horizontally; when separating and removing tiny droplets, the separated particles are quickly carried through these short-path channels, thereby separating them from the clean airflow and directing them into separate channels. This approach eliminates the reliance on gravity-based separation processes, and the size of the particles that settle due to gravity in the airflow is no longer determined by Stokes’ laws and related formulas. For example, the liquid droplets of a certain size separated by the wire mesh demister fall back into the rising airflow. Whether these droplets can break free from the action of the airflow and settle in the liquid collection area at the bottom of the demister for final separation depends on Stokes’ law and related principles based on gravitational settling. Similarly, the liquid droplets of a certain size separated by the baffle plates and swirl plates fall back into the rising airflow. Whether these droplets of a certain size can break free from the airflow and settle into the liquid collection area at the bottom of the demister also depends on Stokes’ law and related principles based on gravitational settling. Through decades of meticulous research abroad, sufficient and accurate fluid dynamics separation technology models have been developed for vane-type demisters. The separation calculation and design system platform is based on conditions that closely mirror those in actual operations, providing precise data guidance for scaling up fluid conditions; this approach overcomes the problem of empirical scaling that has long plagued screen-type, baffle-type, and swirl plate-type demisters. It is also worth mentioning that in traditional cellular barrier-type demisting separation, the size of the cells formed by the \"bridging\" of fiber filaments follows a high-degree Gaussian distribution. While small droplets are blocked and separated by the fine fibers as they pass through these small cells, larger droplets are able to pass through the larger-sized cells and escape ； Therefore, traditional screen-type demister separators are unable to achieve specified, efficient, and quantitative separation of liquid bubbles of a given size. The feather-leaf type high-efficiency gas-liquid demisting and defoaming separator has surpassed traditional mesh-type demisters in terms of quantitative separation efficiency and operational flexibility. For more information on the feather-leaf type high-efficiency gas-liquid demisting and defoaming separator, please visit the HaiChuan Chemical Forum at the link http://bbs.hcbbs.com/thread-1354813-1-1.html.