Biobased chemical feedstock plants closing around the world: Except in China.

[NNadir]

This brief thread applies to the biologically produced compound furfural.

Furfural is a chemical intermediate that was once important in the production of nylon and a number of other polymers, including some polyurethanes. (Furfural is converted to 1,4 butanediol in this process.) The original process for making industrial furfural used corn cobs and oat hulls as feedstocks and is known as the Quaker Oats processes. These biological waste materials contain significant quantities of pentosans - 5 carbon sugars - which are effectively dehydrated to give furfural, also known as 2-furan-carboxaldehyde. Furfural can be decarboxylated (made to give a molecule of carbon dioxide) to give furan, and furan can be hydrogenated to give tetrahydrofuran. It is also possible to make 1,4 butane diol from furfural, and, in this form, it was used to make nylon and other stuff.

It is interesting to note that when biologically based furfural is made into polyurethanes (and other polymers) effectively this is a form of carbon sequestration.

So what's the problem?

Um, well, the problem is that the process is not particularly economic. For many years a process using natural gas and petroleum products has been used to make 1,4 butane diol from butadiene, which is famously used in tire manufacture.

It seems kind of sad in a way, doesn't it?

Well, there is some hope: With petroleum prices rising, the biobased polymer may have a future, especially with a recent process improvement reported by a Thai chemist about a process developed by Chinese chemists:

http://www.journal.au.edu/au_techno/2005/apr05/vol8no4_abstract04.pdf

An excerpt of the report:

In theory, any material containing pentosans can be used for the production of
furfural. Technically furfural is produced by acid hydrolysis of the pentosan contained in woody biomass. Almost all furfural plants employing the batch process use the Quaker Oats technology developed in the 1920’s. They all operate at less than 50% yield, needs a lot of steam and generate plenty of effluent waste. Moreover their operating costs are high. Hence such plants throughout the world are closing, with the exception of simple low cost Chinese plants (Dalin Yebo Trading 2004).

Some have resorted to continuous processes. Westpro modified Chinese Huaxia Furfural Technology is an example of a leading current continuous process furfural technology (Westpro 2004). It uses fixed-bed reactors and continuous dynamic refining, which gives high yields of furfural, including byproducts, at low production costs. The technology requires only low capital investment and is thus especially suited for developing countries...

Technical details are included.

Good stuff.

It is worth noting in this context that one of the world's original plastics, cellophane, was wood based.

[eppur_se_muova]

1. Thanks! You may recall furfural is a compound dear to my own heart ...

and one of the examples of ag-waste products I like to cite (the others being acetone and 1-butanol, both of which are now made from petroleum ... **SIGH***).

[NNadir]

2. Well, I think we will see a return to biobased feedstocks of this type.

There's also been a lot of work done over the years on syn gas from biologicals, which is, I think, a superior approach to fermentation.

I'm not sure I recall your furfural posts, but I'm sure they were very good.

The system seems really cool, and I like it that it can operate in rural, poor areas using a continuous process.

I never realized before today that the Quaker Oats process had yields below 50%. I looked into the matter because I was thinking about batch processes because of the alleged $1/gallon ethanol.

As for the one buck a gallon ethanol, I'll believe it when I see it.

[eppur_se_muova]

3. Yeah, I didn't know about the 50% yield either. Bummer.

I had big questions about that $1/gallon EtOH, but Wired is not the source to answer them, evidently.