Dry gas filters

The natural gas passing through the transmission lines, always contains some pollutant particles; however, the flowing gas at times could only contain solid particles and lack any moisture. In these conditions, the use of dry gas filters or strainers for separating very fine solid particles is highly recommended. Solid particle separation is feasible in a dry gas filter by using filter elements. Typically, filter elements are made of polyesters. To inform the operator at the time of replacement of the filters, a pressure difference indicator (DP gauge) is placed on a vessel that displays the gas pressure drop, through the filter.

In the in-line type, the gas is filtered by passing from the inside to the outside, directed to the outlet nozzle. In the standard type of vertical or horizontal, the direction of gas is from the outside to the inside of the element filter. Depending on the design and quality of the filter element, their separation efficiency varies for particles of different sizes. Typically, dry gas filters are used in gas refineries for the purification of exhaust gas from dehumidification units or in pressure reduction stations. In thegas refineries, it is common to use filter separators or filter coalescers due to the presence of moisture and liquid droplets in the gas stream.

Filter elements:

Filter elements are usually made of glass fibers. Also, a perforated plate is responsible for providing resistance for the filter cartridge against stream pressure, and in addition, helps better distribution of the flow through the cartridge. Fittler 

cartridges can separate dust particles and impurities sized from 3 to 50 microns. The benefits of filter cartridges are high surface area, low-pressure drop, and relatively high lifetime.

Separation efficiency

Typically, dry gas filters have a high separation efficiency, although this is different for particles of different sizes, which means that the larger the size of the contaminant particles, the higher separation efficiency. Typically, dry gas filters can isolate 100% of particles sized three microns and larger, although for particles between 1 and 3 microns, efficiency drops to 99%. The decrease in efficiency is also shown for particles less than 1 micron.

Applications

• Purification of exhaust gas from dehumidification units
• Purification of exhaust gas from catalytic reactor
• Purification of gas entering measurement station and CGS
• Purification of incoming gas into compressors as fuel
• Purification of gas entering valves and regulators

Suitable for filtration

• Catalyst dust
• Absorbent particles from dehumidification
• Particles formed due to erosion of the tube wall