Can fiber mist eliminators be used for dust removal?

There is a lot of dust in the fan outlet pipeline, mainly due to inadequate dust removal; should a demister be used to remove the acidic sludge? It can only cause resistance to rise!

If dust removal is inadequate, the cycle of mist eliminator clogging will definitely shorten, resulting in a higher frequency of cleaning.

Using a demister to remove dust! That’s the wrong approach from the start! If it must be done, it’s better to have two demisters, so that they can be switched between each other, with one in use and the other as a backup.

If the flue gas is not clean enough, the CK demister elements cannot be used as they will get clogged very quickly. Use a screen instead.

Dryer foam catchers generally use mesh pads instead of candle eliminators. Perhaps the screen isn’t easy to get clogged.

In the 1980s and 1990s, the domestic sulfuric acid industry also experimented with plain ceramic filters installed at the outlet of fans, but these are no longer in use today. So, the approach mentioned above is completely wrong; it’s going in the wrong direction!

Using a mist generator as a dust collector creates too much resistance to the gas flow! This results in low pressure at the fan inlet and a reduced volume of air flow. It is not allowed in industrial processes!

You are dealing with smelting flue gas; if you want to remove dust, consider power wave washing!

Our company’s process flow is from venturi to scrubber tower to electrostatic precipitator and then to drying tower

You can take a look at our company’s process for producing sulfuric acid from metallurgical gas: http://www.mecsglobal.com.cn/sulfuric_acid/metallurgical.htm

It would be best to be able to replace it online as well, but that doesn’t seem very feasible! ! !

It is not recommended to use fiber-type demisters or wire mesh demisters in dusty operating conditions, nor to replace wire mesh demisters with fiber-type demisters. The reason is as follows: Fiber-type demisters that use composite glass fibers achieve a higher demisting efficiency than mesh-type demisters using metal fibers, but both essentially belong to the category of traditional pore-blocking demisters. 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 lattice barrier interception 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 clogged by solid particles and gels that can be carried 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 strands 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 defoaming separation technologies, screen-type defoamers 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 situations where the gas stream contains solid particles, gels, or liquid droplets. To address the shortcomings of screen-type demisters, such as frequent clogging, short operational life, and difficulties in operation and maintenance when used to remove foam from 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 significantly. Baffle and swirl plate demisters do not escape the control mechanism based on gravity separation; therefore, 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 techniques at that time, these techniques relied on basic empirical designs; there was a shortage of model data to guide the scaling up of fluid conditions, leading to continuous issues with such empirical scaling. 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, 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 performance, a wider operating range, 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 mechanisms in the separation process, and no longer depends on Stokes’ laws and related formulas, which are based on gravity separation, to determine the size of particles that settle due to gravity within the airflow. 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 specific size can break free from the airflow and reach 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 resemble 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. The feather-leaf type high-efficiency gas-liquid demisting and defogging separator combines the advantages of cyclone plate demisters and baffle plate demisters, such as low pressure drop during demisting in dusty conditions and resistance to clogging by dust particles; it also surpasses traditional mesh-type demisters in terms of quantitative separation efficiency and operational flexibility. It is recommended that colleagues pay more attention to the vane-type high-efficiency gas-liquid demisting and defoaming separators, which have been widely used in recent years for new process packages, new projects, and the renovation of existing installations