The dwindling supply and exponential growth in the demand of
fossil fuels have motivated researchers t o explore alternative
resources and technologies for fuels and chemicals. The utilization
of the relatively large amounts of glycerol side product (10wt.%)
formed in bio-diesel manufacture is a major factor in the overall
cost effectiveness of the process. Therefore, use of this glycerol
as a renewable feedstock to produce value added chemicals is
crucial to biorefinery economics.
Slide 3
Descrition (or glycerin, glycerine) (C3H8O3) : is a simple
polyol compound.
Slide 4
Descrition (C 3 H 8 O 2 ): It is a colorless, nearly odorless,
clear, viscous liquid with a faintly sweet taste, hygrosc opic and
miscible with water, acetone, and chloroform.hygrosc
opicmisciblewateracetonechloroform Ways of obtaining:by catalytic
hydrogenolysis Industry interest: industrial solvent, antifreeze,
deicing agent and approved additive in food, cosmetic and ph
armaceutical industries
Slide 5
Descrition (CH 2 (CH 2 OH) 2 ): This three-carbon diol is a
colorless viscous liquid that is miscible with water.diolmiscible
Ways of obtaining: by bacterial fermentation Industry interest:
Plastics based on this monomer exhi bit better product properties
and higher light stability th an those produced by 1,2-propanediol,
butanediol or e thylene glycol. 1,3-Propanediol can also be used as
a polyglycol-type lubricant and as a solvent.
Slide 6
In this assignment, 1,2-PDO has been obtained with two
hydrogenlysis methots. We are going to discuss the best aspects of
each one
Slide 7
The catalyst in this experiment is an admixture of 5 wt.%
Pt/Al2O3 and 5 wt.% Ru/ Al 2 O 3. The Pt/Al 2 O 3 was chosen to
promote the aqueous phase reforming of glycerol to hydrogen,
whereas Ru/Al 2 O 3 was chosen to facilitate the hydrogenoly sis of
glycerol by in situ hydrogen generated.
Slide 8
It is demonstrate that the admixture catalyst outpe rformed the
individual catalysts with respect to 1,2-PDO selectivity and yield
under without added hydrogen condition. The yield of 1,2-PDO was
also higher with the admixture catalyst when compared to the
externall y added hydrogen condition.
Slide 9
The results with 5% Ru/A l 2 O 3 and 5% Pt/Al 2 O 3 ad mixture
combinations an d the monometallic cataly sts on glycerol hydrogen
olysis in absence of exter nally added hydrogen at 493 K are
compared in these graphs.
Slide 10
Glycerol is converted into hydroxyacetone (reaction
intermediate) through the dehydration, followed by the
hydrogenation into 1,2-propanediol, with a yield over 96%. In this
process, the dehydration needs relatively high reaction
temperatures, whereas the hydrogenat ion favors low temperatures
and high hydrogen concentration.
Slide 11
The main catalyst is Cu/Al 2 O 3, it doesnt present
deactivation until 200C and whit that, it would be obtained the
best yields and selectivity The best temperatures for this process
are betwee n 170 and 200C
Slide 12
The production of 1,3 PDO has been carried out us ing two
bacterias: Clostridium butyricum and Klebsie lla pneumoniae
Slide 13
The experiment includes fermentations in batch culture,
fed-batch culture and continuous culture. This experiments were
carried out in shake flasks and a fixed-bed bioreactor. Results
showed that the NaCS/PDMDAAC microcapsule has desirable properties
such as biomass enrichment in the microcapsule, enhanced substrate
tolerance and stable activity of cells respect of the no
encapsulated cells.
Slide 14
Maximum concentration of 1,3-propanediol (5560 g/L) was
obtained in batch and fedbatch cultures. Continuous culture has the
advantage of relatively high productivities,however, its
1,3-propanediol concentration is not high enough to reduce the load
of downstream separation. Also, there has been growing interest in
a more e conomical route that utilizes glucose as a lower-co st
feedstock.
Slide 15
The great difference of this bacteria is that it present s a
strong tolerance at the inhibitory effect of the 1,3- propanediol
and glycerol, even at high concentration s of this substance at the
chemostat. It means that 1,3-PDO can be carried out with pure or
industrial glycerol. A great advantage for the industry.
Slide 16
In this assignment we have studied the production of 1,3- PDO
with batch, single-step and two-stage continuous cultures. The
medium yield for glycol is 55%, in single-step continuous, large
quantities of 1,3-PDO have been obtained with low concentrations of
glycerol, however if t he flow increases, the concentration
decreases of 1,3 - PDO. having a second stage could be mainly used
to further in crease the product concentration and to completely
use t he residual glycerol.