Is a filter needed to separate silicon powder after hydrogenation?
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As the title suggests, current hydrogenation reactors are equipped with cyclone separators for the separation and recovery of silicon powder, but the results are not very satisfactory – the separation efficiency is low, and a large amount of silicon powder still makes its way into subsequent equipment. Is it necessary to add another filter after the cyclone to further remove the remaining silicon powder?
This post was last edited by cslgwbb on 2017-11-28 at 16:24. Traditional cyclone separators, due to the lack of a professional and precise computational design system, coupled with an unreasonable inlet structure that facilitates the formation of secondary swirls, further reduce the already suboptimal separation efficiency of these separators. As a result, there is a large discrepancy between the actual separation efficiency in operation and the efficiency calculated based on designs, and in some cases the values are even incorrect. New types of efficient gas-solid separators, such as multi-factor cyclone mother-son separators, have replaced traditional cyclone separators through technological upgrades. Utilizing its patented technologies and a precise design and calculation system platform, the company has developed multi-factor cyclone mother-son separators that offer significant improvements over traditional cyclone separators in terms of separation efficiency, operating pressure drop, operational stability, and operational flexibility. Upgrade traditional separators for use in the petrochemical, refining, natural gas transmission and processing, large-scale chemical manufacturing, metallurgy, pharmaceuticals, food, and environmental protection industries.
Silicon powder has a relatively high density, and the use of a multi-factor cyclone mother-son separator enables efficient and stable separation of particle matter with sizes of 5 microns or even smaller from gas streams, achieving a separation efficiency on the order of 4N. If the process also requires the removal of particles of even smaller size, such as 0.3-micron particles, it is possible to consider adding a filter after the cyclone separator.
When installing filters in the outlet pipeline of the hydrogenation reactor for polysilicon projects, the following issues must be taken into consideration: 1. The filter elements can easily become clogged by dust particles, resulting in high operating pressure drops; it is necessary to consider the operating pressure and the allowable level of pressure drop； 2. When using filters, it is necessary to consider spare units and spare parts; moreover, for the convenience of replacing the filter elements, it may be required to install quick-release blind flanges ； 3. Unless the process has special requirements, filter elements must be used to achieve stringent removal of dust with very small particle sizes ； Otherwise, try to avoid using filtration methods that are prone to clogging and result in high pressure drops ； 4. Due to the large amount of silicon powder carried by the airflow, a filter cannot be used alone; instead, a high-efficiency cyclone separator, such as a multi-factor cyclone parent-child separator, must be employed first to remove the vast majority of the dust in advance ； The extremely small amounts of dust that escape or remain in the treated airflow are further removed by filters to eliminate fine particles, thereby ensuring a long service life for the filter elements.