【Filtering and Purification】Two types of filter elements in the coalescing separator
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Coalescing separators are primarily used in the filtration and purification of oils, generally to separate the oil and water components in oil-water mixtures. Hereinafter, the coalescing separator is referred to as a coalescer. There are two types of filters used in coalescers: coalescing filters and separating filters. Their functions correspond to their names – one serves to coalesce particles, while the other serves to separate them. In the oil separation system, the coalescer filter element is the core of the entire system. As the oil mixture flows into the coalescing filter element, the element captures the ultra-fine fibers present in it, which helps to trap solid particles and liquid droplets. Meanwhile, the oily liquid coalesces into larger droplets that fall to the bottom of the container. This is the process that takes place when the oil mixture passes through the coalescing filter element. Subsequently, the liquid enters the separation filter element; due to its strong oil-loving and water-repelling properties, it is able to exclude water entirely, resulting in pure oil free of water flowing out of the coalescing separator. The coalescing and separation filter elements refer to the coalescing element and the separation element found in a coalescing separator; together, these two elements are used to transform oil containing impurities into pure oil. http://a3.qpic.cn/psb?/V12b9Gmf1wzEGr/
Three types of filter elements can be used in coalescing separators: filtering elements, coalescing elements, and separating elements, with the first two being more commonly used. In the liquid-liquid separation mode, the latter type of separation filter element is also used. For filter elements, the flow of fluid usually occurs radially \"from outside to inside\" through the element; the larger the outer diameter, the larger the outer surface, and thus the greater the capacity of that surface to hold solid particles. The main function of a filter element is to remove solid particles from the fluid it filters, while also providing pre-coagulation effects. These types of filters tend to clog easily during use and require frequent replacement and maintenance, but their production cost is low; especially when made of PP material, the operating cost for filtering solid particles is also low. In a coalescing filter element, the flow of fluid is usually in a radial direction \"from inside to outside\"; the larger the outer diameter and outer surface, the slower the flow velocity as the fluid moves from inside to outside, which greatly facilitates the sedimentation and separation of larger droplets that have formed through coalescence. The main function of the coalescing filter element is to cause tiny liquid droplets to grow rapidly through the coalescing material made of composite glass fibers in the filter element, thereby creating the necessary conditions for subsequent sedimentation and separation ； It also has the function of filtering solid particles. These types of filters tend to clog easily during use and require frequent replacement and maintenance; however, their production cost is high. They are generally used in liquid-liquid coagulation applications rather than primarily for removing solid particles. Otherwise, it is difficult for enterprises to accept their high operating costs. Oil-water separation filters are often used in applications where high-level liquid-liquid separation is required. Its application is based on the premise that the proportion of the dispersed phase is very small; it is mainly used in liquid-liquid separation processes to remove trace amounts of the dispersed phase and improve the purity of the continuous phase. It is not suitable for situations where the content of the dispersed phase is significant, otherwise the separation effect is not ideal.
Yes, for the first pre-filter; however, many users omit this device in order to save costs
May I ask if these types of filter elements can be reused? Or reuse it after cleaning?
Filter elements are generally made from multi-layer fibers, which are shaped through methods such as piling, weaving, winding, bonding, melt spraying, and sintering. Solid particulates of different sizes and shapes get trapped and accumulate in the channels at various layers of the filter element, namely the surface layer, the middle layer, and the deep layer. In particular, particles that reach the middle and deeper layers of the filter element are often trapped by the interwoven fibers, preventing them from moving. The commonly used flushing and back-flushing methods are only effective in removing particles accumulated on the surface of the filter element, while they have extremely low efficiency in removing particles that are embedded deep within the filter element ； For filter elements that have had their surface cleaned, the separation efficiency does not return to an optimal level; they often need to be replaced after just a few cleanings. Of course, unless wedge-shaped screens with a single-layer rigid structure and primary separation precision are used, reverse cleaning can be employed to achieve satisfactory regeneration; however, such wedge-shaped screens with a single-layer rigid structure are only used for the primary removal of particles with a diameter of 20 microns or more. For reactive particulates, it is theoretically effective to use reactive solutions for reaction cleaning; for example, weak acid salt particulates can be cleaned using strong acids, while amphoteric and acidic oxides can be cleaned using alkalis ； But in reality, the reaction requires a longer time and a certain temperature; therefore, prolonged immersion at higher temperatures is needed, and satisfactory reactive cleaning cannot be achieved merely through short-term contact with water. Cleaning methods, especially reactive cleaning, require additional investment in equipment for preparing the reaction solution, storage, pressure increase, as well as related facilities and pipelines ； It also consumes chemicals and generates wastewater from cleaning agents; the treatment of such wastewater is troublesome and costly, and it poses a risk of chemical pollution emissions. Therefore, for the filter elements used in most projects abroad and some projects in China, cleaning, regeneration, and reuse are no longer considered. The main reason is that the regeneration efficiency is not very satisfactory; it entails costs related to auxiliary equipment, treatment expenses, and environmental pollution risks, resulting in little or even negative technical and economic benefits. These situations, experiences, and lessons require domestic enterprises to reflect on them.
The first filter element cannot be reused, while the second filter element can be washed and reused 2-3 times
Does your company manufacture coalescing oil removal equipment? Could you send me some materials at yaofeizhige@163.com? Thank you
Does your company manufacture coalescing oil removal equipment? Could you send me some materials at yaofeizhige@163.com? Thank you
NOVEL Company designs and supplies internationally advanced gas-liquid coalescing oil removal separators as well as oil-water and oil-liquid coalescing oil removal separators; please visit NOVEL Company’s website at www.novelenergytech.com for more detailed information. The materials you need have been sent to the email address you specified; please check it.