Biomedical Engineering Reference
In-Depth Information
The super critical fluid method for biodiesel production was developed by
Sinopec and tested in a 200 ton/year pilot plant. Its characteristics include simple
pretreatment of raw material, adaptability to various raw materials, simplified
post-processing, and less wastewater discharge. In 2010, CNOOC applied this
technology to build an industrialization demonstration plant with a biodiesel
production capacity of 60,000 ton/year, but an update on its economic performance
was not available when this chapter was prepared.
3.5 Processing of By-Product Glycerol
In the preparative process using the above-mentioned technologies, whether
traditional acid or alkali catalysis, lipase catalysis or in a supercritical fluid system,
glycerol is produced as a by-product up to 10%, depending on the ratio of
triglyceride and fatty acid contained in the feedstock [
3
]. Taking into account
biodiesel as a bulk commodity, the amount of glycerol produced is very signifi-
cant, and must be processed properly to validate biodiesel production.
Researchers in the Department of Chemical Engineering, Tsinghua University
have successfully converted the by-product glycerol into a value-added product
1,3-propanediol (PDO) by biological transformation [
36
,
37
]. PDO is an important
block chemical with a potential market for the production of the excellent polymer
polytrimethylene terephthalate (PTT) through the polymerization reaction with
terephthalic acid. This technology has now completed industrial demonstration.
4 Constraints and Perspectives of Biodiesel Development
4.1 Feedstocks
Currently, illegal collection, purification, and re-sale of waste oils as components
for edible oils are making waste oils scarce for biodiesel producers. The estab-
lishment and enforcement of strict regulations on waste oil management in China
is urgently needed to support their use in biodiesel production.
To avoid competition for feedstocks with food (edible oils) production, the
biodiesel industry will rely more and more on energy crops for sustainable feed-
stocks. At present, breeding of high quality energy crops such as J. curcas and
Pistacia chinensis Bunge has advanced. Further research will focus on their low
cost and large-scale production. Meanwhile, genetically modified energy crops
may increase oil productivity significantly, resulting in large cost reductions. Since
most forestlands in China are located in mountainous areas, collection and
transportation of energy forestry crops is labour-intensive and costly, and the
corresponding infrastructure must be established.
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