What’s Raffinate ?
A raffinate describes any material that remains from a chemical or mechanical treatment after a desired chemical or material has been removed. It can identify a liquid or solid and can also be processed with additional steps or treated as a waste material. Even if a raffinate is not used to recycle additional products, it may require further processing to avoid environmental problems when sent to a landfill or disposal site.
When crude oil from the ground is processed in a refinery, a mixture of carbon-based petroleum products is produced. Similar products can be created from natural gas or methane reactions to form complex organic or carbon-containing molecules. Different processes can be used to extract the desired compounds, including distillation by boiling liquids or extraction of solvent or water from liquids or solids. After either of these processes is complete, a raffinate remains, which is often processed to remove additional materials.
A common raffinate stream in oil processing is known as the C4 stream. The term C4 refers to the four carbons in the various processed molecules. A C4 molecule is defined as in the butane family and may contain butene, isobutane and isobutylene. All of them have four carbons in their molecules and are valuable as raw materials for plastics and fuels.