Compressors are machines designed to compress natural gas by increasing the pressure and decreasing the volume of the gas.
They function like a pump, and when applying pressure to propel gases through a pipeline, for instance, the volume of the gas invariably decreases.
According to KBDelta, a firm specializing in manufacturing and supplying natural gas compressor valve parts, this process usually generates heat, which is why most compressor stations install aerial cooler systems.
These compressors have wide applications in different industries. They are commonly used to transport natural gas through pipelines, store purified gases, move heat in refrigerator systems, and pressurize aircraft cabins.
How gas compressors work
A compressor works by squeezing natural gas to increase the pressure and thus forcing it to move from one place to another. By design, compressors can be set to increase the pressure in stages or steps until the gas reaches the desired delivery point.
In a compressor station, natural gas enters through a pipe, passing through filters to remove unwanted substances, including liquids and other matter. Once the gas is purified, it is then directed to other pipes where it is distributed to desired locations, possibly storage tanks.
Natural gas compressors are used throughout these stages. They are regulated by computer programs to supply adequate pressure for processing in each compartment.
Types of gas compressors
There are two major types of gas compressors namely, positive displacement and dynamic.
Positive displacement compressors
The mode of operation involves confining and compressing a set amount of gas in a dedicated chamber, after which it is discharged at elevated pressure.
Positive displacement compressors can either be rotary or reciprocating.
Rotary compressors allow a certain quantity of gas to inflow into the dedicated chamber and compress it using mechanical designs such as screws.
There are five types of rotary compressors:
- Liquid ring
Advantages of positive displacement compressors:
- Low cost
- High versatility
- Great efficiency
A reciprocating compressor, also called a piston compressor, uses a piston driven by a crankshaft to compress the gas. Crankshaft is a mechanical component that converts reciprocating or linear motion into a rotational movement.
There are three types of reciprocating compressors:
- Double acting
- Simple acting
Advantages of reciprocating compressors:
- High discharge pressure
- Good for portable use
- Offers wide pressure range
- Delivers high pressure at low capacity
- Low speed
Dynamic gas compressors
Dynamic gas compressors, also called turbo compressors, continuously compress gas as it flows through them instead of requiring the gas to be trapped in a chamber.
There are two types of dynamic gas compressors:
Advantages of dynamic gas compressors:
- High flow rate
- Flexible and easy to build
- Energy efficient
- Low maintenance cost
- Suitable for large-scale applications
Tips for choosing the best gas compressor for your application
Not all types of gas compressors are suitable for every usage. For example, in the oil and gas industry, the two major compressors used are reciprocating and screw.
Considering the following factors can help you decide;
Number of required stages
Determine the required number of stages needed for your gas processing. Reciprocating compressors, for example, can deliver up to 0.6Mpa pressure for one stage and 20 or more for stages more than 6.
Once this is decided, the pressure needed per stage should also be calculated. The expected temperature generated at the inlet and outlet of each stage should also be evaluated to make an informed decision on the type of cooling system to install.
The climate of the area where the compressor will be installed is essential. Temperatures can affect the performance of a compressor. Hence, a model that is designed for colder climates may not optimally perform in hotter climates or deserts.
The compression ratio measures the work a compressor must do to generate a specific quantity of pressure. It is calculated by dividing absolute discharge pressure by total suction pressure.
A compressor for a single stage can handle a 1:1 to 8:1 compression ratio. A two-stage unit will be needed for a compression ratio from 8:1 to 12:1; anything above this will require a three-stage compressor or more.
Once you decide on the best natural gas compressor for your application, ensure all maintenance recommended by the manufacturer is carried out as at when due. Schedule a routine check of the scrubbers and filter to ensure the machine optimally delivers.
Detecting a problem on time can prevent it from getting complicated and save you from spending on repair or replacement.
Lastly, only source your compressor valves from reputable manufacturers or suppliers.