Hi Keith and Everyone,
Don't know if anyone is still interested in this stuff, as
someone posted a message that the patent could be viewed on a website that they
gave the address to, so if anyone wants me to continue after this post please
let me know.
#5 Detailed Description of the Preferred Embodiments continued
Figure 1 provides a basic flow diagram for the glyceride reaction process
employing a continuous
reactor. Throughout the description of the process diagram, the various process
vessels will be
numbered between 1 and 99, with the various process streams being numbered
beginning with 100.
While the following discussion will describe a continuous reactor process for a
transesterification
reaction of glycerides with an alcohol ROH, one skilled in the art will
recognize the process principles
apply equally well in other process settings such as ones using batch reactors
and separation processes as well as reactions producing alternate products to
the alcohol esters as well as processes
beginning with fatty acid feeds.
A glyceride containing feed 100 is mixed with an input alcohol stream
102. The choice of alcohol will be a function of the desired reaction product,
and typically such alcohols as methanol, ethanol, propanol, and butanol are
chosen for practical reasons, however, one skilled in the art will readily
recognize the flexibility of choices and non-limiting aspect of the above list.
This input alcohol stream 102 contains approximately a stoichiometric
quantity of alcohol necessary to quantitatively react the
glyceride feed 100. While the reaction will require some excess alcohol, that
needed excess is
contained in a critical fluid recycle 104 which provides a transport medium
that solvates the reactants
to create the required process conditions. The exact critical fluid employed
for a given reaction will
depend on specifically chosen process parameters such as temperature, pressure,
desired reaction
products, solubility of the reaction products, quantity of excess alcohol
needed to drive the reaction
to completion, post reaction separation processes and chosen catalyst. Examples
of possible critical
fluid solvents are carbon dioxide, sulfur dioxide, methane, ethane, propane, or
mixtures thereof, with
or without critical fluid co-solvents such as methanol, ethanol, butanol, or
water. Naturally, to the
extent quantities of the critical fluid are lost during the process they can be
replenished with a critical
fluid makeup stream 106.
The mixing of the input feed 100 (substance containing free fatty acids
and/or glycerides), the input
alcohol 102, the critical fluid recycle 104 and critical fluid makeup 106
streams, creates a reactant
input stream 108 which is fed into a continuous reactor 10. The temperature
and pressure of the reactant input stream will depend on its components and the
desired process parameters. The important criteria for the critical fluid is
its ability to dissolve the reactants. Reaction temperatures
should be within 20% of the critical temperature of the fluid as measured in
Kelvin, and pressures
within 0.5-15 times critical pressure as modified by any co-solvent. Reaction
temperatures are typically
in the range from about 20 to 200 degrees C with reaction pressures in the
range from about 150 psig
to 4,000 psig.
The transesterification reaction generally proceeds in the presence of a
catalyst either acidic or
basic. Liquid acids and bases, such as the common inorganic acids HCL, H2SO4,
and HNO3, and
inorganic bases NaOH and KOH typically provide the needed catalytic activity.
Additionally, the use
of a critical fluid medium allows for use of a solid phase catalyst with either
acidic or basic surfaces
such as microporous crystalline solids such as zeolites, and non-crystalline
inorganic oxides such as
alumina, silica, silica-alumina, boria, oxides of phosphorus, titanium dioxide,
zirconium dioxide, chromia, zinc oxide, magnesia, calcium oxide, iron oxides,
unmodified, or modified with chlorine,
florine, sulfur or an acid or base, as well as mixtures of the above group or
an exchange resin with acidic or basic properties. Where solid catalysts are
used in the reactor, they may create a catalytic
packed bed or float free inside the reactor.
To be continued,
David Cruse
[Non-text portions of this message have been removed]
Biofuel at Journey to Forever:
http://journeytoforever.org/biofuel.html
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