Syngas is an abbreviation for synthesis gas, which is a mixture comprised of carbon monoxide, carbon dioxide, and hydrogen gases. The syngas is produced by the combustion of a carbon containing compound or material in the absence of an ideal amount of air. This type of combustion is called a partial oxidation process. Things that can be gasified include biomass, plastics, municipal solid waste and natural gas.
Syngas has many uses all on its own, or it can be further processed to make higher hydrocarbons, liquid fuels and chemicals. On its own, it can be used as fuel for typical internal combustion engines and gensets to produce power, or it can be used in power plants as a fuel for heating water for steam turbines. However, depending upon the source of the syngas, it may require purification and cleanup. COSTELLO can help with this process.
What can be Used to Create Syngas?
The whole process begins with a feedstock. This is the material that is going to be converted to syngas. There are a broad range of feedstocks that can be used to create syngas including:
- Natural Gas – Natural gas is an excellent starting material for syngas production. Natural gas that is typically flared in fracking operations could instead be captured and converted into more useful syngas.
- Petroleum Products – This can include end-of-life plastics or petroleum byproducts from other chemical processes or refining. What typically would be discarded as waste can be converted into something useful.
- Coal – Instead of burning coal, why not convert it to syngas? It is more environmentally friendly and has many more uses than the coal itself.
- Biomass – Biomass is anything from paper, vegetable waste, fruit waste and wood refuse. All of these items can be gasified to produce syngas. Syngas made from these types of materials will always require further purification and clean-up.
The syngas can even be further converted to other types of hydrocarbons such as straight chain hydrocarbons including naphtha, diesel and wax or even aromatic hydrocarbons such as toluene, benzene and xylenes.
The Purification Process for Solid Feedstocks
The gasification of solids such as a biomass or recycled plastic will create syngas but also contaminants such as tars, particulate ash & carbon, ammonia, hydrogen chloride and possibly hydrogen sulfide. Before any further use can be made of the syngas, these byproducts must be removed and the syngas cleaned up.
The first step in the cleanup process is to remove excess ash and carbon particulate. This is followed by removing tars, then ammonia and finally hydrogen chloride and hydrogen sulfide.
If the syngas is to be used for making higher hydrocarbons, the carbon dioxide and water must be removed, and then the ratio of hydrogen to carbon monoxide must be adjusted to a suitable value for the downstream catalytic processes.
The Production of Syngas from Natural Gas
For a natural gas feedstock all sulfur bearing compounds must be removed first. Then in a pre-reformer and autothermal reformer the natural gas is converted to syngas. The hydrogen/ carbon monoxide ratio can be changed with a water-gas shift reactor and/or a membrane system. Because natural gas is such a clean burning fuel, no further cleanup is required.
What Can Syngas Be Used for?
Other than being used as a fuel, syngas can be further converted to become a broad range of products including:
- Dimethyl Ether
- Mixed Alcohols
- Aromatic compounds (BTX)
With the appropriate downstream process, you can use syngas for a broad range of applications. The best part is that some of these facilities can be using materials that what would otherwise be waste streams.
COSTELLO has the Engineering Expertise to Design Your Syngas Cleanup and Purification System
Are you looking to make the most out of everything your plant has on hand? Then trust COSTELLO’s expert engineers to start you down the path of syngas production and refining. Contact Rocky at COSTELLO to learn more.