With the increasing cost of fuel and the desirability of biodiesel, many companies are putting effort into the development of commercial-scale production plants. According to the US Department of Energy the production of biodiesel has grown six-fold since 2004.
Two companies at the forefront of this market are Benefuel Inc of Chicago and Seymour Biofuels, based in Indiana. In October 2007 the two companies announced definite plans to construct a new biodiesel refinery in Seymour, Indiana to convert waste fats and oils into a quality biodiesel product.
The new plant, which is due to open in late 2008, will use a new solid acid dual metal catalyst technology developed by Benefuel and the National Chemical Laboratory (NCR) in India. Following development of the solid fuel catalyst technology in conjunction with the NCR using small scale plants in oil plantations in India the refinery in Seymour will be the first commercial scale application of solid acid catalysts for this purpose.
The new refinery will cost $25 million to construct and will produce 10 million gallons of biodiesel a year. Feedstocks can vary between waste grease and oil from the rendering industry to soya oil, palm oil or any low-grade vegetable or animal based fat product.
Solid acid catalysis
Biodiesel refineries have mostly relied on a liquid base catalysed system (sodium methylate) in stirred tank reactors which can produce biodiesel with a good yield but requires a washing step (five gallons of water per gallon of oil) to remove alkali waste products. Disadvantages of the process include the fact that the catalyst becomes poisoned by free fatty acids; the system relies on a batch process which also produces a very low grade glycerine side product that is not easy to purify.
In contrast, the use of solid acid reactors requires the passing of a mixture of methanol and the oil/grease over a high surface area fixed catalyst bed where transesterification occurs to produce methyl esters of fatty acids for use as biodiesel. It also produces a 98% pure glycerin which can either be marketed as a separate chemical feedstock or be used as a fuel additive and blended into the biodiesel as an oxygenator.
No water washing process is required, making the refinery more environmentally friendly. In addition, the refinery reactor can be run as a continuous process with in-line monitoring and remote management, which is more efficient and produces a higher-quality product.
The commercial scale facility at Seymour will require a footprint of only 1,000 square feet and is expected to come online in late 2008. The facility has been sited at this location by the City of Seymour to take advantage of the availability of a variety of feedstocks from agriculture and also because it is close to road and rail links.
The modular refinery is being constructed by Seymour Biofuels and the catalyst technology is being provided by Benefuel. Benefuel has obtained an exclusive worldwide licence for the catalyst technology and is expected to offer to establish small-scale commercial biodiesel refineries for other companies using a scaleable modular design within short timeframes.
Refineries will even be portable to some extent, as the modular design will allow transportation to different locales if required by availability of feed stocks.