Syngas: What is it, how is it made & where is it used?

Syngas, or synthesis gas as it is otherwise known, consists of a wide range of other gases, and tends to be used in fermentation and pyrolysis procedures. As the name suggests, it is a man-made gas which is created through chemical processes using waste products as feedstocks.

It has a wide range of uses and is now being hailed as a greener way to generate electricity, which is why it is proving to be so popular in a growing number of industries, and yet many people still know very little about it.

In this article we take a look at how syngas is created, the many different uses that it has and what the benefits of syngas can be.

What is syngas?

Syngas is made up of hydrogen, carbon monoxide, carbon dioxide, methane, nitrogen, water vapours and other hydrocarbons and condensable compounds and it creates a synthetic natural gas. It is considered to be extremely versatile as it can not only be used in its own form, but it can also be used to separate out and purify other elements such as hydrogen and methanol.

The term synthesis gas comes from the fact that it is created through gasification, rather than being extracted from the atmosphere or other fossil fuels. By using waste products to create a form of energy, it is possible for many industries to have their own onsite power production facilities, which is not only economical, but also makes them less reliant on outside providers, giving them greater control over their own processes.

A huge benefit of syngas is that is releases far less carbon emissions than many other alternatives, and so it is now being seen as a viable form of green energy.

How is syngas made?

Syngas occurs when carbon-rich feedstocks are put into high heat, high pressure and oxygen depleted conditions. Traditionally, these feedstocks have been made up of natural gas or coal, however, as gasification technology has developed, other feedstocks have been brought into use, including petroleum coke or biomass.

The feedstock that is used will affect the concentration of compounds within the syngas and the emissions that it gives off, and so this needs to be considered carefully before the process begins.

The feedstock then reacts with carbon dioxide, water vapour and oxygen during the gasification phase, and this reaction is triggered by thermal decomposition for oxygen-rich materials.

However, the gas that this produces is still in its raw state and is therefore not pure enough to be used, and so a purification process is required. This helps to eliminate various impurities such as ash, tar, sulphur compounds, water vapour and carbon dioxide. Once this is complete, the hydrogen-oxygen proportion may need to be adjusted depending on how the synthesis processes have been applied.

This process is known as gasification, however there are other methods that can be used. Steam Methane Reforming (SMR) uses methane and steam to produce hydrogen and carbon monoxide, whilst partial oxidisation causes hydrocarbons to react in limited amounts of oxygen or air and is often favoured in smaller applications that cannot accommodate a gasification set up.

Where is syngas used?

The main benefit of syngas is that it is incredibly versatile as a fuel and is therefore finding itself in use across a number of different industries.

It is often used in the process of power generation, as it can be burned in gas turbines as a cleaner and more efficient way to produce electricity, thanks to the fact that it does not need fossil fuels and creates much fewer pollutants and greenhouse gases.

This can help to not only make syngas a form of renewable power, but also to convert potentially problematic waste into useful and environmentally friendlier fuels.

One of the other large components of syngas is hydrogen, and it is possible to separate this out and purify it for use on its own.

Syngas fermentation uses syngas as a carbon energy source and uses micro-organisms to convert it to other things such as chemicals and fuels. The most common products from this process are methane, butyric acid, acetic acid, butanol and ethanol. The process only needs low pressure and temperature and has a high reaction specificity. It also does not need a specific ratio of carbon monoxide and hydrogen in order to work.

The chemical industry is one the largest users of syngas as they tend to use feedstocks that the most economical to produce or buy. Syngas can be used as the foundation for the production of other chemicals and fuels thanks to the Fischer-Tropsch synthesis process. This allows for the production of other fuels such as methanol and diesel.

Syngas is also used to produce a wide range of fertilisers, solvents and synthetic materials thanks to the nitrogen, methanol and ammonia that it often contains. This means it can be used for the production of a wide variety of plastics like polyurethane and nylon as well as resins, pharmaceuticals, adhesives and paints. The minerals and solids that are produced can even be used as slag for roadbeds, ensuring that any waste is kept to a minimum.

Syngas looks as though it could be the answer to a lot of concerns over producing clean energy on an industrial scale.

It now bridges the gap between traditional fuels and completely green and renewable sources, and by using feedstocks from other sources within an industry, it can help in a number of different processes, without the levels of greenhouse gases and pollutants that we are used to and minimising any waste production at the same time.

That means it can benefit a wide number of industries both environmentally and economically as we move towards a cleaner and greener future.