Turning manure into clean fuel: biodiesel production needs two feedstocks; an oil or fat and...

Smithfield Foods believes manure generated at its pig-raising operations can provide a source of clean, renewable fuel if the energy value of the waste stream Call he economically captured, processed and utilised. To this end, Smithfield formed Best BioFuels to apply its proprietary technology

A facility is under construction at Circle 4 Farms near Milford, Utah, where the manure from more than 25 pig-finishing barns will be conveyed underground to a digester complex. There it will be concentrated, heated and introduced into an anaerobic digester system.

The biogas (65% methane/35% carbon dioxide) generated try the digester will be captured, cleansed of hydrogen sulphide and pressurised. This pressurised biogas will be processed, via steam reforming and onward conversion, into methanol and higher alcohols.

Methanol is an important ingredient in the production of biodiesel, an approved alternative motor fuel. As methanol comprises only 15% of the raw material stream for biodiesel, it will be transported to a biodiesel manufacturing plant located remotely near the source of oils and fats, which represents 85% of the raw material, and the end-user market.

European biodiesel demand

There is a big market for biodiesel in Europe, with more than 900M gallons consumed in 2002. This is mainly due to the fact that biodiesel in Europe is not subject to excise tax, whereas the excise tax on petroleum diesel is more than 10 times that imposed in the US.

Biodiesel in Europe is mainly based on rapeseed oil, unlike in the US, where most biodiesel is produced from soyabean oil. While this gives a high-quality product, the price of the nil portion of the biodiesel at recent soyabean nil prices is at least double that of petroleum diesel at the filling station.

As a result, Best BioFuels has concentrated on the development of biodiesel technologies that use animal fats as the feedstock. These fats have historically cost about half the price of soyabean oil. As animal fats have a high free fatty acid content, the development of an efficient esterification system is vital to their use in biodiesel, otherwise inefficient conversion will erode the price advantage.

The use of animal fats will enhance the competitiveness of Best BioFuel's biodiesel. However, without relief from the state and federal excise taxes, it will not be on a parity with petroleum diesel.

The focus has historically been on reducing emissions from petrol-fuelled vehicles. Only recently has attention been drawn to particulate matter emissions (PM) from diesel engines. As biodiesel cuts PM by more than 50%, this should increase demand for the fuel.

Best BioFuels believes the combination of biomethanol with animal fats in an efficient conversion process will result in a biodiesel product that is competitive with petroleum diesel. The use of biodiesel will work towards national energy independence and support agriculture--two of its parent's main aims.