Just wonder what you think. Any concerns or questions?

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How is the oil heated?

How to you safely determine all the catalyst is dissolved before introducing it to the oil?

Did you make this or is this a new commercial-made one with a website with more info somewhere?

Thanks!

The oil is heater with either a 120v 2000w or 240v 4500w water heater element through a welded bung on the galvanized tank that can be wired to a thermostat. The only way that I know how to ensure that the catalyst is fully dissolved is to open the lid and inspect the black bung at the bottom of the tank to see if there are any cyrstals on or around it. I realize that this is not the best method, but we've got plenty of fresh air where the unit is working. Do you have any suggestions to help make it safer to use? Any and all questions/comments are welcome good or bad. I just want to make a safe, stable, and easy to use processor.

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You could put a sight window on the top of the methoxide tank so you could see the black bung without opening the lid.

Some sort of safety mechanism to prevent the element from being on when the oil tank level is below the element's level. And air-exposed water heater element is a sure"fire" way to have a bad biodiesel experience.

Since your processor is so nice and open to welding on a bung, this sort of level sensor might be just the safety ticket.

I'm still trying to figure out the best way to incorporate one into my Pseudo-Appleseed.

The sight tube is a great idea. As far as the air exposed element goes, the element will be on a switch powered thermostat, so that you only turn on the heating system once the WVO/Bio is above the element. We put the element as low as possible to fit the long 240v element in without hitting the other side of the tank.

I've heard that galvanized isn't good to weld on because of the fumes it creates, and it isn't compatible with long term biodiesel exposure.

Ken

I had the tank made by a fabrication firm that handled all of the welding, and leak testing for me. Regarding the reaction of galvanized metal to bio, I have found no reaction at all in a 6 month, constant contact, time frame. I have several samples of bio with different grade of galvanized steel submerged in them, and I aggitate the samples several times a week, and have had zero noticable change in sample or biodiesel upon inspection.

I have no personal experience with galvanized and biodiesel other than a few fittings that I stripped before use. It's just what I read somewhere. Very nice looking set-up, by the way.

Ken

From the MSDS for methanol:

"...coatings of copper (or copper alloys), zinc (including galvanized steel) or aluminum are unsuitable for storage as they are attacked slowly."

Since the reactor vessel contains Methanol for the entire process, this is a concern and is why Biodieselers prefer carbon steel parts to zinc-coated ones. As I recall, there are two seperate chemical actions responsible for this degradation.

The cathodic protection provided by galvanization is simple a coating of Zinc Oxide, which is soluble in Methanol (?); this coating will be removed, leaving an unprotected surface which will quickly oxidize again on exposure to the air. The new coated will be removed, replaced, and so on, slowly removing the coating (and depositing metal in your product/byproduct). I recall seeing a spontaneous reaction between zinc and a methoxide mixture (forming Hydrogen gas and Zinc Methyl? - input from a master chemist needed please).

Great idea though - just change out the material if you're building with longevity in mind. If this design is cost effective, it appears to be a well-needed addition in the marketplace (at least the main tank portion).

I really appreciate your input. I went through the test phase for quite some time, with longevity in mind, so I went with the galvanized. I can get the carbon steel for slightly cheaper, and then again with the galvanized plumbing I can reduce cost with the carbon versus the galvanized. I did do seperate testing with methanol, biodiesel, glycerin, and methoxide, and nothing seemed to break down the coating on the surface over a 6 month time. Not to say that nothing happened, just nothing that was visable. Again, thanks for the input.

Looks pretty good. A little more research and study and you'll come up with a design that will have longevity, produce a fuel that qualifies as biodiesel and be marketable.
Galvanized pipes in water systems does equal longevity but in gas systems it does not.
Even if you can't see what is happening degradation is occurring.
Specifications for quality, exposure limits, etc. are in PPM's (parts per million) and small fractions of one percent - levels not visible to the eye or sensed by the nose.
Keep working at it, you'll get there.

Already working on the next one out of carbon steel with carbon piping. Thanks for all of the input.

Since you have a fab shop to work with I suggest putting on larger connections, size them up to 1.5" for non restricted mixing action.

I thought about that, but the pump inlet/outlet is 1" so it can only flow as much as the pump can pull, right? It is easy enough to have tehm change the bung to whatever size I need.

You may end up with a 1.5" pump some day, many here have. Also with poor suction its always good to have a larger fill, for example most centifical pumps have an inlet that is 1/2" larger than the discharge.

Jeremy this unit looks like it addresses a lot of safety concerns regarding processors. It would probably not make any difference to the longevity whether you used galvanized piping or not since it will be coated with oil most of the time. There will be some inadvertant exposure of various surfaces to the methoxide so some reaction to the zinc on the surfaces would happen. The "hot setup" with respect to the heater being on is a flow switch which activates the heater when flow is sensed in the piping that way if the pump is switched off , burns out or the piping is plugged the heater shuts off. This works best with an inline heater which would fit into your design well and will ensure a long heater element life by providing high fluid velocity past the heating surface, keeping it relativly cool. Good luck Dan

Where do you find a "flow switch"? I was planning on having it switched, and thermostat controlled, but also set to turn off when the timer turned off.

Wow, a flow meter to control the heat is an awesome idea.

If you connect a Pitot tube to a low pressure differential switch, you have a cheap flow switch.

flow meters are the right choice to protect your pumps and heaters from running dry.
I sell them to several professional BD plants here in europe. They use allways thermal flow switches, made of hastelloy HC2 or HC4. The problem is the price! These flow switches with the special made electronic costs up to 1500$ !!
They choose hastelloy because its the only material to withstand the methoxid for a longer time.
pitot tubes are normaly used for the control of air or gas flows, not suited for fluid systems, because the the small vents and ducts in the tube are prone to clogging. Any change in the diameter of the pitot tube will change its characteristics so with any residues inside the tube, it becomes useless because the switching point is changed.

for more information: flow switch

Dieter

Dieter,

Those are some EXPENSIVE switches!!

What about pressure drop across an orifice or inline restriction? Would that work in a liquid system?