Welcome to the Ethanol - Ester Reactor Build
work shop class room
Feb 28 2009
After reading a lengthy document about Process Intensification "PI" by Dr. G. Dolbear , where the
where the professor talks about speeding up chemical and organic reactions 80 fold and 1 hour
reactions get turned into Milli seconds, I was convinced that an ordinary circulation pump on a batch
style reactor wasn't going to cut the mustard on ethanol biodiesel. Process Intensification or "PI" in
short is the ability to rub, squeeze, mix and evenly distribute molecules of two substances together
promoting their reaction to get as far as possible to the equilibrium point much sooner.
Rotor Stator Shear Mixing is a very good example of "PI" where one round disc is stationary and the
second disc is spinning at high speeds. The gap between the two disks is adjustable and can be
called the clearance. The fluids to be reacted enter this shear mixer "reactor" in the center of the two
disks and travel outwards within the clearance set. Increasing the speed of rotation and tightening
the clearance should promote "PI" Reactions that take normally an hour may now take one second.
In some circumstance's the reaction will happen without requiring a catalyst or sometimes requiring
much less, "PI" also increases the yield of the finished product. Adding grooves and holes to the disc
allows the mixture to form small whirlpools, eddy's and vortex's promoting a more even blending and
mixing action. This tiny vortex is much more efficient than one large vortex in the "stir crazy pot style
reactor" The document also speaks of "PI" using ultrasonic sound, microwave, and static mixer.
Most batch style reactors DO use some sorts of primitive "PI" in the design that works well with
Methanol Esters. Example's are the mixing action of a circulation pump impeller and the splashing
effect of the fluid entering the top of the reactor and splashing down on the product within. To build
processor temperature helps. Others use high speed impellers mounted to a long shaft to stir-crazy
the contents of the pot creating the vortex and mixing action. Improving the mix action will most
definitely promote the reaction which I feel is important for Ethanol Biodiesel production.
Topics of consideration while designing Methanol and Ethanol Biofuel Reactor Design
- DRY DRY DRY Feedstock , Ethanol , and Methanol Need to be without moisture
- vacuum processor for ethanol recovery for reuse and design and build a container to
house 3A desiccate beads.
- Methanol uses to promote separation and dissolve KOH catalyst
- Process Intensification methods "PI", heat, pressure,shear force,etc
- consider the benefit of centrifuging byproduct in line to remove moisture and glycerin
during the reaction to prevent "reaction stall"
- temperature vs vapour pressure. Too build pressure upon a reaction to increase "pi"
- To adapt the Fool Proof two stage acid-base reacting method by Alexs Kac with
ethanol assuming that good quality feedstock is not available
Left is a photo of a colloid mill where the stator and rotor can be adjusted to a set
clearance causing Process Improvement and thus a speedy reaction. High speed shear
mixing accomplishes the reaction process in a very short duration of time. This high
shear mixer requires an additional pump to supply fluids to the unit. Mixed and reacted
product are then returned to the vacuum reactor. In the case of a continuous flow design,
very careful metering must be done to supply the proper amount of Methoxide and
This Shear Mixer has no stationary stator but just a shaft driven rotor, the shaft extends
40 inches below the electric motor inserting the shear Mixer low in the Ethanol Methanol
wvo mixture The electric unit will be mounted to the top of an access cover on this
sealed vacuum reactor. Access is granted through removal of the lid. This particular unit
measures 3.75 inches in diameter and is driven by 7.5 HP electric
Well I have decided to stay with the batch style reactor for one simple reason."FEEDSTOCK"
Feedstock WVO always has different titration values no matter what the source. It is almost
impossible to save set settings on flow devices after all continuous flow reacting more or less means
"push the green button" with brand new never been used oil and watch. My experience tells me that
wont happen with WVO. Although i did seriously consider it with the fool - proof method. With the
fool proof method, one could possibly react acid stage in one large batch first in reactor A . Then
with continuous flow reacting the KOH base stage COULD be set up with a High Shear Pump and
settling tank. Now if the quality test is not passed how do you fix it? Too difficult to react the second
time by tweaking. NOW wait, if the byproduct settling tank were a second reactor , then simply drain
glycerin and reprocess until it passes the methanol test and wash test!.
Twin Reactors is the way to go here.
Reactor A with cone shaped bottom, will need to design build a stainless steel hot water
hydronic coil mounted near the bottom inside to heat and preheat the oil to min 65C. Next a
full vacuum is drawn from the top and a coaxial dryer collects the water vapours. This
reactor will not have a circulating pump that can be turned on to speed up the drying of any
residual water droplets that could be hanging around near the bottom as seen in Joe Streets
free processor plans. Instead I stumbled across a very efficient way of bubble drying the
product when I had a tiny pipe thread air leak. Under full vacuum I now carefully open a tiny
needle valve in the lower drain pipe assembly until the air flow matches about 1 HG of
vacuum drop with the vacuum pump running. This tiny amount of air expands into football
size bubbles that circulate the contents of the dryer. The additional air also helps sweep the
very last amount of vapour from the unit. Incredibly the vacuum drying time was improved
from 4 hrs down to 1 hr. A safety interlock can be added to close the needle valve circuit in
case of vacuum loss with a simple vacuum actuator valve.
Reactor A will also become the acid stage reactor using Alexs Kac's FOOL PROOF method.
Sulphuric acid and methanol (hopefully ethanol) will be administered to this reactor with the 7.5 HP
High Shear shaft style mixer running. After settling and draining up to 1-3% Free Fatty Acid "water
soluble" glycerin, this vacuum reactor can now be set up to recover most of the remaining methanol
and stored for reuse on the next acid batch. Hot methanol vapour will pass through a long narrow
tube filled with 2 kg of 3A desiccant beads which we still need to design and build. The methanol
vapour is then condensed in the coaxial dryer and collected for reuse. Interestingly enough , ethanol
and KOH reactions are so sensitive to water contamination that One part of water can quench up to
4.67 parts of catalyst.
Vacuum reactor A will now proof dry the whole batch inside this vacuum reactor to remove any
water that may have been produced from this Acid Stage Reaction. This vapour will bypass the
desiccant beads and be collected in a separate liquid trap. Sample this oil occasionally with the
titration method to check the FFA content. Remember that the molar strength of the sulphuric acid
needs to be deducted from the acid number after the titration to determine the real titration FFA value
of the oil, to neutralize one ml of sulphuric acid you will need 1.885g pure KOH , in my case the KOH
is 85% so 1.885 / 0.85= 2.218g KOH per litre oil. If your acid number ends at 2.2 or 2.5 then your acid
reaction worked great.
The dry preheated esterfied oil is now ready to be sent over to the high shear mixer for reaction with
Ethanol and KOH
Vacuum Reactor B will be in charge of reacting KOH and ETHANOL. It's design will require an in line
high shear pump to mix the Ethoxide and oil, and will operate much on the same principle of Joe
Streets reactor. This reactor then can drain glycerin, tweak the reaction again until passing "the
Quality Test" by Jan Warnqvist , wash and vacuum dry finished B100 Ethyl-Ester . Back to the
welding shop Cheers.
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March 4 2009
Holy crap I just found brand new High Shear Pumps made in India out of 304
Stainless steel for a bargain. I know i should shop at home but all the USED
shear pumps and in line reactors are still selling for 20k cost 50k new!!! Gees
someone I guess had to pay the patent's and R&D back when they were new.
The unit pictured to the <LEFT is more of a High Shear Homogenizer with very
low flow. It's design will work very good with ethanol, but has a different design
than the Colloid Mill which can adjust down to as little as 0.007 inch clearance.
The new India units have a double pressurized mechanical seal, any electric
motor of choice , Stainless steel engine shroud. This unit only flows 75L per
minute at 7.5hp. I don't know when I will have time to come back... Soon
|Discussion forum about this project is hosted at www.nonprofitfuel.ca
|March 5 2009 Answered the phone today to have a rather nice fellow on the phone inform me
that they can supply 99.9% anhydrous ethanol denatured with 2-5% gasoline for this project. After a
few minutes of talking I find out that Randy spends some spare time on a Lake right near me in
Cranbrook on weekends. Gotta have coffee with this chap for sure! Permolex is a (wheat) grain
ethanol producer located in Red Deer Alberta supplying fuel grade ethanol for road use to North
America. The facility also produces flower,gluten and livestock feed . Sounds pretty sustainable to
March 11 2009 More Fantastic info. Mike from Hielscher USA Inc. contacted me with ultrasonic
biodiesel reactors and probes. The ultra sonic process looks fairly impressive to emulsify fluids
down to the nanno particle size. Here is the link for more info to the company.