Is it necessary to install a demister or mist trap in the separator?

I don’t understand. With the same weight, a horizontal separator has a greater processing capacity than a vertical separator, right? The center of gravity is also low. Defoaming and mist supplementation should be able to improve the separation efficiency.

Why does a vertical structure develop a “bag-like” shape? ~~Should the separator be equipped with a wire mesh mist catcher, or to prevent the presence of free water?~~

It depends on the precision requirements for gas-liquid separation: if the requirements are not high, a wire mesh demister can be used; for higher precision, a coalescer is generally employed.

Vertical installations can have a higher height, which is better; of course, it’s also possible to go for a horizontal design with a larger size, but that isn’t as cost-effective. A defoamer is usually installed to help reduce liquid carryover.

The author can find answers to the issues related to separators in \"HG20570.8 Design of Gas-Liquid Separators.\" I quote some of the relevant content as follows: Question 1: When there is a large amount of liquid, and the residence time between high and low liquid levels is 6–9 minutes, a horizontal gravity separator should be used. When there is a small amount of liquid, the liquid level height is not determined by the residence time, but rather by the minimum distance of 100 mm between various adjustment points; in such cases, a gravity separator should also be employed. Question 2: Gravity separators are suitable for gas-liquid separation of droplets with a diameter greater than 200 μm. ***(Without screen type) The screen separator is suitable for separating liquid droplets with a diameter greater than 10–30 μm in gases. ****(With screen) Question 3: See details in “HG20570.8 Design of Gas-Liquid Separators”

Old members are welcome to participate more in the forum discussions

It’s not the equipment that causes bag-shaped accumulation; rather, it’s due to limitations in platform height. In the process, the control valve at the outlet of the molecular sieve tower is located on the platform, with a cooler following it, and then a vertical separator. It’s best if the level drops step by step along this line. If such a gradual drop cannot be ensured, then measures to drain out the excess liquid are necessary, but these measures cannot completely prevent the impact of bag-shaped accumulations of liquid on the production process.

If there are no issues with the process design, free water can generally be removed effectively through a gas-liquid separator. If complete dehydration is not achieved, it indicates a design flaw, and technical modifications such as adding freezing or adsorption-based dehydration methods can be employed. As for what you mentioned regarding bag-shaped structures or the lowest point in the system, hydrophobic valves or regular drainage of condensate can be used~~

This post was last edited by luoli519 on 2016-4-21 at 22:25. Based on my many years of experience in designing gas-liquid separation equipment for natural gas, such separators require high precision in separation, and therefore often adopt a structure that combines a coalescing filter element chamber with a dynamic foam removal chamber. Regarding question 1, \"Vertical separators are necessarily more effective than horizontal separators\": Both vertical and horizontal separators can achieve the same separation efficiency; the key lies in the configuration of the internal components and their installation method. Vertical separators have the following limitations in terms of their application: 1. The internal components need to be replaced and maintained frequently, which is inconvenient due to the high location of the top cover of the vertical separator; working there is difficult, and more auxiliary equipment and manpower are required. 2. The amount of liquid carried in the feed gas should not be too high. This is because vertical separators of the same diameter have a lower capacity to store liquid compared to horizontal separators. In situations where there is a large amount of liquid in the feed gas and a long residence time for that liquid is required, vertical separators are not suitable. 3. The height of the separator and the piping layout should not be set too low; it is necessary to arrange them at a higher position. Typical natural gas gas-liquid separation technologies have high requirements and often necessitate the use of coalescing filter cartridges; therefore, during the regular maintenance of such separators, it is necessary to replace the coalescing filter cartridges periodically. In such cases, it is better to avoid using vertical separators and opt for horizontal separators instead. In other cases, professional separator design companies can recommend the use of vertical separators based on the actual operating conditions. The advantages of vertical separators include less space requirement, no need for a filter element compartment; moreover, their diameter is usually smaller than that of horizontal separators when the feed gas contains low levels of liquid. Additionally, the cost advantage becomes more significant as the operating pressure increases. Regarding question 2, \"Is it necessary to install a demister or mist trap in the separator?\", the answer is yes; a demister must be installed. This is because the tiny liquid droplets in the gas stream, after passing through the coalescing filter element, rapidly and efficiently coalesce and grow; some of these droplets settle and separate on their own, while those still suspended in the gas stream need to be captured and separated using an efficient demister, in order to ensure that the gas output from the separator meets the required standards. As for demisters, there are traditional structures based on mesh or filter screens that use pores to block and intercept particles, as well as advanced designs such as vane-type high-efficiency gas-liquid demisting and separation devices. Since the pores of traditional screens and filters have a **small size and follow a Gaussian distribution, while the small pores capture tiny droplets, larger droplets manage to pass through the larger pores, thereby preventing accurate separation of the liquid mist. Furthermore, the feather-leaf type high-efficiency gas-liquid demisting and defogging separator offers advantages in terms of operational flexibility, operating pressure drop, and equipment size that are difficult to match by traditionally structured demisters. Regarding question 3, \"the installation location of the demister or mist trap,\" it is necessary to use a specialized and precise dynamic separation design platform to accurately calculate the contraction effect of the airflow as well as its contraction angle, in order to determine the appropriate installation location for the demister ； Otherwise, in actual operation, the effect of airflow contraction causes some demisters to operate inefficiently or not at all, while those demisters that are operating under other conditions experience a reduced efficiency in removing foam and mist due to the high flow velocity of the air. The airflow contraction effect requires a precisely designed platform based on specialized and accurate dynamics; it is one of the core technical secrets of the few professional separation technology companies. I’m sorry, but I can’t disclose this technology, nor can I provide technical documents such as manuals. The installation position of the demister, determined by the airflow contraction effect, imposes strict requirements on both vertical and horizontal separators, not just on horizontal separators. For more technical information on natural gas coalescing separators, you can visit the link http://bbs.hcbbs.com/thread-1354813-1-1.html on the Haichuan Chemical Industry Forum.