TECHNOLOGY: Process Converts Trash into Oil

Bill Siuru

A new biomass conversion process could help to reduce the tons of trash in the nation's landfills, as well as reduce the dependence on imported oil used to produce petrochemicals. The process, developed by Biofine Corp., Waltham, Mass., reportedly can convert almost any cellulose or starch-containing biomass feedstock into levulinic acid (LA), a chemical building block that then can be used to manufacture value-added products. The company claims that it can turn waste from landfills, agricultural industries and paper mills into products such as environmentally-friendly herbicides and pesticides, gasoline additives and other chemical intermediates currently made from petrochemicals.

For any waste-to-usable-products process to be commercially successful, it must pass two tests. First, LA has to be produced cheaply enough to compete with chemical products or intermediates. Second, there must be a viable market for these products.

While LA can be synthesized by several methods, frequently they form large amounts of side products and intractable materials, or require expensive feedstocks. However, because of its two-reactor system, this new process eliminates many of the existing problems with LA production including side product formation and the resulting separation problems. Low-cost feedstocks can include diverse cellulose-containing waste such as paper mill sludge, urban waste paper, agricultural residues and cellulose fine from papermaking.

Currently a relatively small specialty chemical market for LA exists, about 1 million pounds per year at a cost of $4 to $6 per pound. Using this process, however, LA production costs could fall as low as 4 cents to 10 cents per pound, depending on the operation's scale, according to Biofine. The U.S. Department of Energy projects energy savings of more than 75.6 trillion British thermal units (Btus) per year and waste reduction of about 26 million tons per year by 2020 by using this new technology.

However, three years ago, a research consortium formed - including Biofine and Chemical Industry Services, Richmond, Va.; the National Renewable Energy Laboratory, Golden, Colo.; the Pacific Northwest National Laboratory (PNNL), Richland, Wash.; and the New York State Energy Research and Development Authority, Albany, N.Y. - to determine the applications and potential markets for biomass-derived products. They investigated three LA-derived products - methyltetrahydrofuran (MTHF), Delta-aminolevulinic acid (DALA) and diphenolic acid (DPA).

The largest potential use for LA, according to the consortium, is for MTHF production, a fuel extender that can be used to meet alternative fuel fleet vehicle requirements. Up to 60 percent by volume MTHF content can be blended in gasoline without an adverse effect on engine performance. Because it is miscible with gasoline, MTHF can be blended at a refinery and transported by pipeline. In contrast, competitive ethanol must be added later in the distribution process because water contamination can cause phase separation.

Based on 100 billion gallons of gasoline usage in the United States per year, replacing as little as 1 percent - similar in volume to ethanol use in gasohol - would result in a yearly demand of 1 billion gallons of MTHF. This is equivalent to more than 10 billion pounds of LA, according to PNNL, which conducted the research on using LA to produce MTHF.

On the other hand, DALA is a completely biodegradable herbicide that is effective against dicotyledonous weeds but does not harm crops such as corn, wheat or barley. More recently, DALA has been found to be useful as an insecticide and as a component in photodynamic therapy used in treating cancer. The consortium estimates an annual market of between 175 million to 350 million pounds for DALA.

DPA has been used widely to produce polymers. Other applications for DPA include electronics, printing inks, fragrances and medicines. The material easily is prepared from the reaction of LA with phenol, according to Rennsselaer Polytechnic Institute, Troy, N.Y.

DPA can serve in many of the same applications as Bisphenol A (BPA), but BPA is cheaper, which affects the DPA market. Because the Biofine process produces LA at a much lower cost, DPA may become a renewables-based polymer precursor. For instance, if LA were produced for $1 per pound, DPA likely could be produced for $1.20 per pound. At $1.20 per pound, DPA might not only capture 20 percent of the estimated 5 million pounds per year BPA market, but it could be used in new applications. The consortium's goal is to achieve a 15 million pounds per year DPA market over the next five years, which would create a 7 million pound per year market for LA. Potentially, this market could grow to hundreds of millions of pounds annually.

A facility in South Glens Falls, N.Y. currently is hosting a 1 ton per day demonstration pilot of the LA production technology. Recently, all the consortium members were awarded the 1999 Presidential Green Chemistry Challenge Award for the project.