29 December 2014

The things they use to manufacture diesel!

At present, clearly more than half of the raw materials for Neste Oil's renewable diesel are waste and residues. Where do we get these resource efficient raw materials?

Fat into your fuel tank

The meat processing industry also generates materials that are inedible or not fit for human consumption. We are not talking about the bits they use to make sausages or salami; we are talking about the waste generated by animal farms and butcheries. Animal fats are generated in meat processing, in particular, and they are sent to processing plants to be turned into meat and bone meal or rendered animal fat. Rendering is a heating process designed to eliminate pathogens and thus protect the health of humans and animals.

In addition to the manufacture of biofuels, some of the fat waste can be used as animal feed, in the chemical industry, or in energy production. Neste Oil procures waste animal fat from all around the world.

Oil from ethanol production

There are dozens of millions of hectares of corn fields in the United States. A little over one-third of the corn is used to manufacture ethanol. When ethanol and animal feed are being made from field corn, small quantities of technical corn oil – an ingredient not suitable for human consumption – are also generated.

Technical corn oil is cheaper than the corn oil used when manufacturing food. Most of it is used as a raw material by the chemical industry, as an additive in animal feed, and as a raw material for diesel. This means that the more of ethanol, a biocomponent for gasoline, is manufactured, the more of the raw material that is well suited for renewable diesel will be available.

But what about palm?

When palm oil is being made, some of the fatty acids in crude palm oil are split by enzymes and oxidation into free fatty acids that must be removed from the oil by means of distillation. The raw material created during the distillation process is called PFAD (palm oil fatty acid distillate). Around 5% of high-quality palm oil will separated as PFAD. If it takes a long time before the palm fruit bunches are taken to the pressing plant, the fatty acids will start to split much faster, i.e. the fats start to get rancid.

The refining process aims at eliminating as much of the free fatty acids as possible to achieve the purity requirements set for the main food industry raw material, palm oil olein. The more of the rancid fats are removed, the better the oil will taste and smell. The process also improves the oil's color. Fats that cannot be used to cook something or spread onto your sandwich can be used to manufacture renewable diesel. PFAD is used not only to manufacture biofuels but also to manufacture soap, food emulsifiers, and animal feed.

That's right, PFAD is linked to both palms and the food chain. However, few of us enjoy rancid fat to the extent that we'd like to ban the use of PFAD and prevent the battle against climate change. Nobody makes rancid oil on purpose, though: after all, you get ten times the price for the actual product. It is difficult to come up with a raw material better suited for a process residue that complies with the renewable energy regulations.

Pekka Tuovinen
Sustainability and Supplier Compliance, Neste