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Greetings all

Its been a long time since I have posted but I am back with my madness Razz

I pulled my old reactor out form storage and plan to make the following upgrades over time


  • Add a second reactor Tank
  • Increase reactor temperature maybe up to 90C
  • Install a heat exchange to use the hot oil from one reactor to pre-heat the other reactor oil
  • Use an Air Conditioner condenser coil for methanol vapor recovery
  • Add a co2 recycling bobble wash for drying and de-meth
    This will be achieved by firstly purging the air out of the reactor with CO2. Then an AC compressor or blower will be used to pull a vacuum on the reactor and compressing the Vapor (methanol or water) and CO2 in a condenser/cooler. The vapor will condense back into liquid leaving the CO2 to be bobbled back into the reactor through some for of expansion valve
  • switch to sold catalyst with Calcium Oxide (CaO) which will require higher temps to work.
  • Installing an electrostatic separator in the tank
  • Consolidating the CaO into a small reaction chamber out side of the main reactor


The final upgrade is to install a small collection cup under the electrostatic probe to collect falling glycerine when the probe is energized during reaction. The cup will have a small drain to the out side of the reactor into a methanol recovery system. The recovered meth will be re-injected into to the reactor.

All these upgrade are to see if I can make a DIY solid cat reactor and the list is just my preliminary plan of attack to get it done.

I'll post a few pic later of all the equipment I have collected so far


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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Cover; What is the point of using carbon dioxide in your system? I must be missing something.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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It Primary for safety. I did not feel comfortable bubbling Air through the system for fear it might ignite, especial if I want to incorporate some form of electrostatic separation that could cause a spark. Also CO2 is allot easier for me to get versus any other gas.

I should have also stated in my post that this is the preliminary plan and I am sure some items maybe drop or added as I go along

I have also put up some pics of my reactor
Reactor

Current the reactor temperature is limited to just around 65C but this will increase once I replace all the old PVC/Nylon tubes and fitting.


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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have you done any work on the bench with calcium oxide?
 
Location: PEI, Canada | Registered: September 27, 2012Reply With QuoteReport This Post
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so far I am still reading a few research paper like the following before I start any bench testing.
CaO Cat research paper
CaO Cat Nano particles research paper

But is been almost 5-6 years since I processed so I want to get my reactor back up to form and a few batches off before I try the CaO.

Also I want to run a few full scale batched using so preprocessed biodiesel as a co-solvent. From what I've read a 1:1 ratio of BD and Methoxide is a good stating point


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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Got the reactor plumbed up with a new pump and test with some water.
http://www.youtube.com/watch?v=g37DmN-6Loc

The pump pushes enough water to create a nice vortex in the tank


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post



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Hi Cover,
From what I understand, a vortex is not something you want in a biodiesel reactor. If you remove the elbow on the return and let the return blast off the opposite wall of the tank instead, you will get much better mixing and a faster conversion.
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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Thanks for the tip and I can see how a vortex will cause mixing problems with paddle and propeller mixers but dose the same dynamics apple for pump mixing?


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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Thats the way I have heard it mentioned repeatedly around here, vortex = poor mixing. Though I have no first hand experience or experimenting with it. I would think it would be worse with pump mixing compared to paddle mixing too.
One of Fabricators processors had several tangential pump outputs into his reactor to create a vortex and he found that they were counter productive if I recall correctly...
I think the problem is that the vortex sets up dead spots in the lower part of the tank which leads to inconsistent and slow batch turnover. But I am only speculating.
If Murphy or fab see this post I am sure they will chime in.
I am convinced that the best mixing/conversion happens when you can blast the output against the wall of the processor or a deflector plate or something. When the stream hits the flat surface it violently explodes in every direction, ensuring complete mixing of the stream.
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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quote:
Originally posted by Jon Heron:
I think the problem is that the vortex sets up dead spots in the lower part of the tank which leads to inconsistent and slow batch turnover. But I am only speculating.
If Murphy or fab see this post I am sure they will chime in.


Any tank can develop dead spots if not set up correctly. Square tanks are the worst.. flat bottom tanks cause significant problems too..

Also, with the exception of square tanks, almost all stagnation problems can be easily solved.. With round tanks its as simple as adding a few protrusions into the tank to create some turbulence in that vortex.

The problem with this conversation is that there is no reference point.. A 200 gallon tank with a 10gpm pump is going to more easily develop dead spots than the same tank with a 100 gpm pump...

It just depends on how things are set up..

Most of my experience with tank mixing designs come from the industrial painting (coatings) industry.. When we drained a tank, if there were any dead spots, you would see a build up of coagulated solids in that area.. Those solids cost big bucks so we quickly learned how to avoid the issue.


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Registered: March 09, 2006Reply With QuoteReport This Post
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Thanks guys. I'm going to remove the elbow on the pump discharge in the tank to reduce the chance of the vortex forming. To Go a step further, I'm going to try find an old cast iron induction tee mixer I had and install on the same discharge in the tank. The suction of tee is going to be plumbed to pull form the base of the tank.

The tee is the same type sold on Mc master Tee-Fitting Proportional Mixers

Again Thanks for the advise


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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sorry I forgot to add the reactor spec.
Processing volume: 100L
Pump flow is estimate to 30-40 Lpm based on the pump curve.

Therefore the reactor volume turn around is about 3.3 to 2.5 min with the pump alone.

If I find that mixing tee this time could shorten


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post



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sorry for the long delay in an update but during this time I have been working on reactors.

I have completely assembled one reactor and the second unit just needs to be wired up.

I have already ran two batches in the first reactor using oil that titrated to 1ml make my cat ration 1+3.5g/liter and 20% meth.

the batches came out fine with only a few minor probes.

I have also got my hands on a descent size vacuum pump and two refrigerated drinking fountains (one working and the other dead) to help me build a meth recovery system. The concept was to have the vacuum pump pull the meth vapors from the reactor reactor through the drinking fountain condenser, which condense the vapor to liquid that is then collected in a tank. The problem is I am still get vapor carry over to the vacuum pump. I don't think my condenser is too small as the meth tank gets up to 35C coming from a reactor temp of 70-90C. 35c is a respectable temperature for an air cooled condenser here in the tropics. What I'm going to do is use the second working drink fountain to build a refrigerated meth storage tank to further condense the vapor and also prevent reboiling of the meth in the tank under strong vacuum.

I'm also going to look at the cost of using CO2 to neutralize the cat instead of an acid to try to minimize the amount of water introduce in the meth and not to split the soap back to ffa. In addition to this I'm going to try and build a small molecular sieve to dry off the meth vapors before condensing it.

If I have done my chemistry right it will take

44g of co2 to neutralize 80g of NaOh which will produce 18g of water

Taking into account batch volume of 80 liters and 4.5g/l of cat I have a total of 360g worth of cat.
Meaning that (360 / 80)*18 = 81g of water will be produced. That is just 0.081 liter (0.1%).

It is probably less that that due to the cat to soap formation.


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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I have decided to modify the second reactor to be similar to gl push pull system.
With just 2 more valves and a few fittings the pump direction should be reversible


"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning."
 
Registered: July 22, 2006Reply With QuoteReport This Post
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Cover; Have you done a 3/27 test on your product biodiesel, at 20 degrees centigrade? That is 3 milliliters of biodiesel in 27 millilitres of anhydrous methanol? It seems to me that using 3.5 grams NaOH plus titration is a minimal amount of caustic to use. You might benefit by using a little more, if you are not passing the 3/27 test.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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