What are process compressors and how do they work?

Process compressors are an essential component of many industrial systems, but have you ever stopped and thought about what they are? Let’s take a closer look and find out more about these interesting devices…

What are process compressors?

Process compressors are used to compress gases or vapours for industrial use. They work by reducing the volume of gas to increase its pressure.

What are process compressors used for?

Process compressors are used at sites such as chemical plants, refineries, and gas processing facilities to achieve a variety of goals, for example:

Compressing gas for efficient storage/transportation

Circulating gas through a process

Speeding up desired chemical reactions e.g. breaking up long-chain hydrocarbons (cracking)

Different types of process compressors

While the basic goal of process compressors is the same, there are three main types used for different applications:

Centrifugal compressors

Bernoulli's principle states that the total energy of a fluid or gas remains the same: the sum of potential energy + kinetic energy + pressure energy. Centrifugal compressors work by increasing the kinetic energy of the gas then transferring this energy into pressure.

Centrifugal compressors contain internal blades which rotate at high speed. Once gas has entered via the inlet, it is accelerated outwards by the impellor, thereby gaining kinetic energy. Once the gas leaves the impellor, it enters a diffuser which slows it down and reduces the volume, and the kinetic energy is transferred into pressure energy.

The pressurised gas finally exits via the discharge nozzle.

Reciprocating compressors

Boyle’s law tells us that the pressure of a gas is inversely proportional to its volume (assuming temperature and amount of gas remain the same). Reciprocating compressors, also known as piston compressors, work by reducing the volume of a gas, thereby increasing its pressure.

These types of compressors use pistons: when the pistons move down, they draw gas into the cylinder through an open valve. As the piston moves up, the valve closes and the gas is compressed as the cylinder’s volume reduces.

Once the gas is compressed, it is cooled and stored for onward use.

Screw compressors

Screw compressors also work by reducing the volume of the gas, this time with a pair of rotors (or screws). Rotating in opposite directions, the rotors draw gas in and compress it as the space between the rotors and the casing reduces.

Compressed gas is then released via the outlet to be used/stored.

How Rochem can help

If your site uses a centrifugal or axial process compressor, you’ll be interested in keeping it as efficient and reliable as possible. While every stage of a system is important, the process compressor’s function is vital to achieving the desired end product.

At Rochem, we have specialised in processor compressor cleaning for over 40 years. Our products and equipment enable customers around the globe to maintain safe and efficient equipment, maximising production and profit.

Please get in touch to discuss your specific requirements and find out how we can help.