What is Filter Separator?

• Filter Separator is used to remove liquid, small solids (created by the tubing and wind erosion), and other particles from the flow stream. Filter separators, like other gas-liquid separators, can be horizontal and vertical; the most common type is horizontal. If there is a large amount of water incoming gas, the structure of the filter separator is designed to have a “boot” in the bottom of the separator connected with two similar tubes parallel to each other. Retention period required between 3 and 5 minutes for hydrocarbon (oil)-water separation by settling. Sizing the dimension of the filter separator’s each section depends on the calculations and design of the manufacturer or engineering company.

Filter separators consist of coalescing filters and mist extractors inside of its vessel, usually have quick opening closures for maintenance and replacement of the filters.

“Filter separators and coalescing filters are required, when droplet sizes below 3 microns”

• Filter separators have a wide application in gas pipelines, as well as the gas processing plants, for example, acid removal units, when after passing filters separators catch the liquids and condensed hydrocarbons coming from the absorber. In gas processing, adequate inlet separator and filter separator are required to prevent foaming due to chemical contamination. If the absorber is downstream from the amine unit, glycol unit, or compressor, a filter separator is required. Also, the filter separator and the coalescing filter used to prevent fine mists from entering the absorber.
• The solids removal efficiency of the filter separator is 100% when the size of solids is 3 microns & larger, and 99%, when the size of solids is 0.5-3 microns, while liquid removal efficiency is 98% when the size is 8 microns & larger.
• The efficiency of the filter separator depends on particle size, distribution of particles, and liquid loading.

• Typical Horizontal Filter Separator

• Typical Vertical Filter Separator
• Typical Arrangements of Filter Elements

Gas-liquid and Liquid-Liquid Coalescers

Coalescers are used for gas-liquid or liquid-liquid separation. Coalescers are designed by the composition and type of contaminants on the flow media.

Coalescing filters are also used to prevent fine mists from entering the absorber. Liquid-gas coalesces are also used for the removal of fine aerosols in gas production, processing, and transmission. Coalesce cartridges, made of pleated glass fiber media supported by metalcore, which has higher efficiency than traditional separators with mesh pads and vane packs. The reason is higher efficiency is that cartridges contain a much finer pore structure and larger surface area. Coalescers remove 99.5% solids 0.4 microns and larger.

“Iron Sulfide from corrosion can interfere with the liquid-liquid separation, thus the section of liquid collection acts as a holder for the liquids removed from the gas in the vessel upper sections”

Coalescing Filters, normally are vertical, used in natural gas pipelines to remove liquids from the flow streams, where very high gas-to-liquid ratios. Coalescing filters have only filter cartridges.

• Typical horizontal liquid phase coalescers

• Horizontal two-stage coalescing filters

• Typical vertical liquid-liquid coalesce

• Horizontal coalescer with prefiltering vessel

• Typical Cartridge Filter

Source: https://www.hcpetroleum.hk/