The HCL is needed because if you take the methanol from the BD without neutralizing the lye first, the BD starts converting back to oil. So, by neutralizing the lye, you avoid that back conversion, and can demeth both BD and glycerol together in only one step.
About the needles, as far as I know, all syringe needles are stainless steel. The problem is that HCL also corrodes SS. The only metal it doesn't corrode is hastelloy, which is difficult to find, expensive, and as I've been told, difficult to machine.
About getting the needles in bulk, that's an extra problem I have, because here in Florida, you need a prescription to buy syringes and/or needles.
"When you don't think what you say, you say what you think" Jacinto Benavente.
"Wars not make one great" Yoda.
"A pessimist is a well informed optimist"
"There are no stupid questions, but there are a LOT of inquisitive idiots..."
I don't think it would cause any problems in the processor, because once it mixes with the BD, it'll get neutralized by the lye. The only concern is the HCL delivery mechanism, where the HCL is pure (or somehow pure). Once it enters the BD stream, it should be neutralized almost immediately.
Haven't tried anything yet. The next time i go to the farm i'll take some sample jars of Muriatic and stick different materials in to test them. I had wondered how long brake line, viton tubing, vinyl tubing, polypropylene tubing, or rubber vacuum/fuel line would last. The thought with the cheaper of those options would be that i could replace a foot or two of vinyl tubing for about $.23 per foot after each batch and just be done with it.
I looked at it too. According to the Cole-Parmer site, the only materials that are compatible with 37% HCL are ABS plastic, Carbon graphite, ceramic magnet, chemraz (FFKM), CPVC, epoxy, fluorocarbon (FKM), kalrez, kel-fr, natural rubber, NORILr, polyetherether ketone (PEEK), ptfe (teflon), pvdf (kynar), tygonr and vitonr, so I rather use 100% HCL, which at least is compatible with hastelloy, the only metal on the list.
You won't be able to use liquid 100% HCl - it won't exist at room temperature.
Typically 35% is about as concentrated as you can get for room temperature storage.
Muriatic acid is just a solution of Hydrogen Chloride in water. Hydrogen chloride is a gas at room temperature.
So, no 100% HCL then. Damn it!
Do you know how much sulfur is there in H2(SO4)?
Would it be enough for the BD not to pass an emissions inspection, if we use it instead of HCL?
I was looking for something that would withstand the hcl that is cheeper than Hastaloy. I found this.....Tygon Chemfluor.
Would this work in say a 1/16 rigid tubing on your chemical inlet with a pinch valve for injecting the acid.
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You had natural rubber on that list... that stuff is just over a dollar per foot at an auto parts store... why not just go with that?
Tygon is commonly available at hobby shops as model airplane fuel line.
Viton is available on McMaster-Carr.
you could probably find a 1/4" nylon or ABS barb and a reducer to 1/8" ID tubing... that would be capilary enough i think.
Well, for what i'm doing it will be.
I am thinking the natural rubber would take beating if the BD came in contact with it. So what valve would you be able to use that would withstand the acid?
Well, as Drewry said, you're forgetting that the capillary tube would be submerged in the BD... Natural rubber is just not an option.
Tygon used in R/C planes?
I haven't been into model airplanes for little more than 8 years now, but in "my times" (now I sound like a dinosaur... ) we used silicone tubing. Are they using tygon now?
Bottom line: the reason I don't like HCL is because, any way you look at it, it implies complications that we might not have if using another acid. For example, if we could use H2(SO4), we could use stainless steel without a problem. What I don't know is if H2(SO4) would introduce enough sulfur to the fuel for it not to pass the emissions tests.
Tygon fuel line is used for gasoline powerd engines in r/c airplanes. I have a question, can't the hcl be diluted with some other chemical or solucion so it wouldn't be so corrosive but still injectable for our purpose?
There are many different Tygon componds. The stuff used for model airplanes is methanol-proof, but I'm not sure about acid-proof. OTOH, chemical supply houses stock acid proof tubing. Using a pinch clamp is an obvious "solution".
As John said, Tygon is the manufacturer. Their Chemfluor brand the one that is acid resistant. It seems to me as none of that would matter if you don't have a valve that is acid proof as well. I was thinking that if you put the tubing 1/16" to 1/8th" and put a silicone plug in the end of it you could inject through the plug and just replace the plug every so often. or maybe a small tube alone would act a a capillary feed as project mentioned.
and here is a previous iteration from earlier to today. I think it might be interesting to see the learning.
What I am looking right now primarily for is advice/comments about the plumbing: problems I have created, simplifications I could add and anything else you might see. The valve numbering system is based on Graham's drawings, but I had to renumber a few because some now are serving two purposes and one is completely new. Also, I think there must be a better way than numbering the valves sequentially because 3 sets explicitly are open/close pairs (where a 3 way ball valve would do equally as well) and there must be some kind of naming system to indicate this more clearly. I am taking a stab at it here, but I am not convinced there is not a better way yet.
I have some concerns about the sight tube I purchased from McMaster-Carr (http://www.mcmaster.com/) (page 520 of their catalog or search 'sight tube'). The issues is two fold. First, although most people making BioDiesel strongly make the argument not to use galvanized materials, I have read that there is little evidence that it actually is a problem in small home brew operations. This sight tube is plated in something, I am guessing zinc, and although I am not overly concerned about this small object reacting with the methanol (is this false hope?), the HCL is a different story. I have put the sight as far away as I think possible from where I will be injecting the HCL (methanol port). Is this far enough? Do you think the HCL and the galvanized sight tube will cause problems or the HCL be to attracted to the catalyst? The second issue with this item are the seals on the thing. Inside the metal tube is a lip, where a Buna-N washer sits and the glass tube rests on that. On the other end of the glass tube is a Buna-N O-ring and a compression nut holding that in place. I am going to need to replace those Buna-N items with something. PTFE would be the best material to use - right? Do PFTE compress? Anyone have a few o-rings or washers they can spare? Hey, it was the most affordable sight tube by far - $30 for 3/4". Or is all of this overkill and I should lose it and use just a squished sight tube?
PS. At the end of the Photos, there is a 4 minute movie of set up.
Nice videos and pictures, the only thing I can think of is I remember Graham saying he uses his site tube to see the color change and that he smushes it down with a light behind to see it. It might be difficult to see the color change with that sight tube.
Also do you have any pictures of the tank on the side with the venturi on it?
I understand the flow and it should work well.
that heating element tube really makes me nervous. I know graham puts it on the outlet side of his pump, but you've got to figure that he uses a thermostat and a pressure relief on it. Yours, while a pretty slick idea, does NOT have those things. Also, even though you faced the tees upward, the oil may siphon out when the pump is off, which is what people object to.
Otherwise, everything looks great to me!
I was planning on adding a PID to deal with temp. The idea was to replace that boiler gauge with the thermocouple. As for the relief valve...that is a very good idea. I would rather not have to drill one more hole in my tank for the relief return, so is there some way to tie it back in instead? Here is an idea. Near the top of the tank, there is a 2" port (not pictured) that has a 3/4" hole in it that is currently plugged. This hole will only have liquid over it, when the Oil is filled to its highest and of course when I add the 22% of methanol. If I put in a brass swing check valve there, will that hold back the contents of the tank? Or should I just bite the bullet and drill another hole and ask the welder to come back? Darn, and I just returned a check valve to McCaster-Carr!
Doug: I agree with everybody. You did a great job. Congratulations.
About the relief valve, you don't need to drill another hole. Just connect the RV outlet to the other pipe (the one that's used when you reverse the pump's flow) with a tee, and you're all set.