How does Synthesis Gas work?

What is a Synthesis gas?

The synthesis gas is also called syngas. The synthesis gas is a mixture of CH4 (methane), CO2 (carbon dioxide), CO (carbon monoxide), and H2 (hydrogen).   This syngas is a generic term which uses for the synthesis of oxo alcohol, methanol, ammonia, and or the production of hydrogen. 

The energy density of synthesis gas is 50 percent that of natural gas. This gas can’t combust directly, but it can be used as a fuel source. It can also be employed as an intermediary in the production of other chemicals. The manufacturing of synthesis gas for use as a raw material in fuel is obtained by gasifying municipal waste or coal.

Synthesis gas is a most vital factor for many power plants. Therefore, the recovery of these gases is also very important. Different companies are used hydrogen compressors for the synthesis of gas recovery. If they properly recover the syngas, they may lower their capital costs. 

How to produce Synthesis gas?

Syngas can be generated by using multiple methods. It is a very useful medium in the production of fuels and chemicals. The synthesis gas is produced in the following way:

1) Heating Phase

The very first gasification is the gaseous phase. This is a thermochemical process that converts carbon-rich raw materials such as coal, biomass, or petroleum coke into a gaseous compound of carbon monoxide and hydrogen under oxygen-depleted, high pressure, and high-temperature conditions. 

2) Reaction Phase

During the gasification process, the raw material reacts with O2, water vapor, and CO2. This reaction initiates via the thermal decomposition of oxygen-rich material. 

3) Purification Phase

The raw gas is generated by gasification. This produced gas is not clean enough to use. Therefore, a refining or purification process is done to remove contaminants such as carbon dioxide, water vapor, methane, sulfur compounds, tar, and ash. The purified hydrogen-oxygen ratio is adjusted according to the application of the synthesis process.

4) Catalytic Phase

When the synthesis gas makes contact with various catalysts then the metals like copper, cobalt, manganese, or iron are produced.

5) Syngas Fermentation

Syngas fermentation is a bacterial procedure in which syngas uses as an energy source and carbon and transformed into fuels and chemicals through microorganisms. Ethanol, butanol, acetic acid, butyric acid, and methane are the major products of synthesis gas fermentation.

However, synthesis gases fermentation has some limits, like limited mass transfer, low volume productivity, and biocontrol.

Types of Hydrogen Compressors

There are multiple types of hydrogen compressors used for the regulation of the synthesis gas. The most common types of hydrogen compressors are given below:

  1. Piston compressors
  2. Diaphragm compressors
  3. Centrifugal compressors
  4. Screw Compressors

1) Piston Compressors

This type of hydrogen compressor uses a piston for the compression of the gas.  The piston compressor has a compression cylinder in which the piston moves up and down. One of the major advantages of this hydrogen compressor is that it can be easily transferred from one place to another, and it has a low cost. 

2) Diaphragm Compressor

A compressor that uses a diaphragm or membrane to compress the synthesis gas is known as a diaphragm compressor. The diaphragm compressor uses a hydraulic piston with tight sealing so that ionic fluids can’t mix with the gas. 

The diaphragm compressor consists of different parts such as crankshaft, camshaft, diaphragm, and inlet & outlet valves. This is one of the best compressors used in the power plant. 

The main advantages of these compressors are low costs, easy maintenance, and high flexibility compared to other compressors. They are best for high-pressure applications. The diaphragm compressors have a quiet and smooth operation. They don’t have cavitation issues. 

3) Centrifugal Compressor

A centrifugal compressor uses an impeller for gas compression. It consists of an impeller, diffuser, and volute casing. When the gas enters the compressor, it strikes with the impeller blades. The blades transform the kinetic energy of the gas into speed and increase the gas speed. After this, the high-speed gas is sent into the diffuser. 

The diffuser converts the speed into pressure energy. In this way, a centrifugal compressor increases the gas pressure. After this compression process, the gas is recovered and sent to the desired area.

The main advantage of centrifugal compressors is that they have high reliability and have oil-free nature.

4) Screw Compressors 

These compressors use a series of screws for the compression synthesis gas. The screw compressor has drive and driven screws. The drive screw is linked with a shaft that further connects with an electric motor. This drive screw drives the driven screw. As these screws start moving, the gas is sucked into the compressor and trapped between the driver and driven screws. The movement of the drive and driven screws compressor the trapped air. These are energy-efficient compressors.

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