quote:

I'm very excited about the whole biodiesel thing and hope to make a positive contribution to the community soon

G'day Jeff;
It seems you already have. Keep it up and welcome to the forum.

Sorry for beating a dead horse.

Folks,

To discuss behavior of a plastic tank vs. a steel tank vs. a steel tank with a pressure relief valve without much scientific data is absurd.

The "explosion" you all talk about is called a Boiling Liquid Expanding Vapor Explosion (BLEVE). There is specific scientific data already recorded. There is also an incident simulator available. Google BLEVE.

The tools for analysis of enclosed tank boiling liquid behavior available today far outstretch my past experience in the fire service. What I did have experience with is fire cause investigation. From the published pictures here on this thread, no such BLEVE happened. The photos showed plastic tanks melted down to what could have been the liquid level. The fire loading from conventional building materials appeared satisfactory enough to cause the complete destruction of the building.

Has anyone ever done the bar-room parlor trick by taking a drink in a plastic cup and holding it over the flame of a candle? If the cup is held with the lower portion containing liquid directly over the flame, the cup will not melt or burn. This is due to the liquid in the cup being able to dissipate the heat at a rate that keeps the plastic cup below its melting temp.

To me the bottom line is we are making FUEL here. Fires and explosions in petrol processing plants and during its transportation (Google BLEVE) are well documented. It is all fun that we can make cheap fuel at home and thumb our collective noses at the… well whom ever we thumb our noses at.

But, responsibility for setting safety standards must be taken by us, the community, movement, or whatever you want to call this idea, lest our local politicians will OVER REGULATE the process to DEATH.

Is there a section on “standard” safety precautions? I’m not talking, “don’t breathe methanol fumes or you will go blind or crazy.” I mean a set of suggested safety practices and home brew set-ups??

Crazy?

C.

So True. We need to develope a safety standard. This Forum is the perfect place to start it or Insurance companies and fire marshals will shut us down.

Hi Carl.

Would you be willing to help build the standard set of safety precaustions? A group of us have been attempting to create a web site focused on teaching people how to make biodiesel. You expertise would be a great addition to the effort. The web site we are producing is www.biodieselcommunity.org and yes I wrote a cheezy safety article for it. I would welcome your review of it. There is also an article titled "storage considerations" that discusses getting started in biodiesel from a firemans perspective.

In the example shown, there was no fuel in the melted plastic tanks. This room was not the one heavily damaged. The fire started in the wall with an electrical short and due to the structures design spread quickly. The fire department had problems with the fire and called it a "refinery fire" due to the fact that two 275 gallon poly palletized "totes" containing biodiesel melted and spilled the biodiesel "fueled" the fire. Melting poly tanks and dumping fuel in the fire like BLEVE is also well documented.

My understanding is that most fire code is based on "fire ratings" or the time it takes for a fire to pass a barrier under specificed fire conditions. Fire ratings are ususally applied to buildings or structures rather than tanks, but the argument does apply. A higher fire rating give the firemen more time to put out the fire before it spreads. By the properties of the materials poly tanks have shorter "fire ratings" than steel tanks.

When applied to tanks there are two definitions that seem to apply "fire resistant" and "fire protected" These are standardized tests. I may have the termonology off some since it's been a few months since I looked at this. These tests seem to be related to "fire ratings" in overall concept but not specific test conditions. In these tests they roast a tank filled with fuel over a hot flame to see if it survives defined conditions. I have talked with UL about doing these tests, but got busy with other things and never followed through.

You said there was a BLEVE calculator, do you remember the link to it, I can't find it. I'd love to play with it.

BTW the invitation to work on a safety best practices document is open to everyone, not just Carl.

Found the simulator at:
http://www.thermdyne.com/

Rick,
Yes, I think that was the BLEVE calc site.
See, I always stick my 2 cents in then get offered to join a committee

As I said, my experience in Fire Safety is now rather dated circa 1990. I have been a nurse for over 10 years now.

I would be happy to go to the site and see what's up and always give my opinion

One big issue is that each Authority Having Jurisdiction (AHJ) is free to interpret the model codes as they see fit. The only thing they can’t do is make any administrative code change that is less restrictive than state law. I have known a few that get their jollies by making the code as restrictive as they can. (Same type of guys who would drive a Hummer for similar short comings.) My thought is that if we write or influence the writing of the model code, pols usually adopt a model code without really reading it that close.

Model Code = NFPA fie code for fire protection; BOCA for building codes etc.
NFPA = National Fire Protection Association
BOCA = Building Officials and Code Administrators [Building Officials and Code Administrators (BOCA) (published the BOCA National Building Code and other National Codes) is now the International Code Council.] See I told you I was out of date

AHJ = Local Fire Department/Fire Code Official

The BLEVE simulator is no longer available for free.

Writing a model code is more that the BiodieselCommunity.org was designed to handle, but such an effort is not out of the realm of possibility. A set of safety guidelines for homebrewers to follow would be a bit more in line with the site.

I think there is a need for a model fire code for homebrew, but, I'm unsure of how to get one written. Any ideas?

Gosh,
I read the two selections Rick suggested AFTER I spouted off in the above response!

"Storage considerations" is well thought out and Dave covers the bases well. I would echo "ditto" to all of his suggestions and I feel that it is written as plainly as could be.

My fear is the same as his with his statement "...those conditions would be to simply "forbid" the whole deal and make you prove otherwise..."

That was the reason for my passionate plea above. Nothing would be worse than getting the whole process shut down before it ever really took off.
C.

quote:

Originally posted by RickDaTech:
The BLEVE simulator is no longer available for free.

Writing a model code is more that the BiodieselCommunity.org was designed to handle, but such an effort is not out of the realm of possibility. A set of safety guidelines for homebrewers to follow would be a bit more in line with the site.

I think there is a need for a model fire code for homebrew, but, I'm unsure of how to get one written. Any ideas?

Ahh,
Actually writing a model code would be rather deep.
Basically, I think that if there is a standard set of rules/code/precautions/safety considerations - now I'm not sure of the exact terminology either, that the community could point to when something (a fire) happens and say, "hey, here is the set of safety considerations and procedures that the community has 'adopted' and recommend to all who home-brew," then, I think there would be less cause to have a knee-jerk reaction by the AHJ to shut everything down.
It's easier for them to swallow the thought that it was just some dumb-@$$ who didn't follow the rules rather than a whole group promoting unsafe activity.

As I sit here and ponder, actually this forum and the biodieselcommunity.org has become somewhat of the quasi-authoratative body on the subject no?

Sorry to ressurect another old thread, but in the begining of these pages comeone mentioned a processor 50% full would produce less pressure then a processor 90% full when both are held at the same tempeture. How Is that possiable? If 1 gallon of water is at 110c in a sealed tank it will have 20.799psi. 100 gallons would result in the exact same pressure.

Logan Vilas

Water when heated (or frozen ) expands at a given rate , I forget the expansion rate right now and don't have my book handy . If you would figure that for one gallon it is not much , figure it for ninety gallons it adds up to quite a bit . Went and got my book .
Water expands 1/23 of its volume when heat from 40 F to 212 F which is roughly 10 cubic inches not a lot , but 900 cubic inches are . That figure out to 3.896 gallons . Dan

quote:

Water when heated (or frozen ) expands at a given rate , I forget the expansion rate right now and don't have my book handy . If you would figure that for one gallon it is not much , figure it for ninety gallons it adds up to quite a bit . Went and got my book .
Water expands 1/23 of its volume when heat from 40 F to 212 F which is roughly 10 cubic inches not a lot , but 900 cubic inches are . That figure out to 3.896 gallons . Dan

That makes a little more sense, but not a large amount. Forgive me chemistry was a weak subject for me. As you heat the liquid it undergoes a volumic expansion. Once enough heat is added the molucules start breaking appart into vapor. if you raise the pressure by not venting the vapor then it stops until the whole batch reaches the next degree and releases a little more vapor.

I would think the pressure rise from volumic expansion would be no more then the vapor pressure of the liquid at 1 degree higher then it's atsmopheric vapor point.

Is that line of thinking completely wrong because there's something like an expansion pressure of liquids that can be calculated like the vapor pressure is calculated? If this is the case whould anyone have a chart or referance to that for any vegetable oils? What is the correct term for those calculations?

Logan Vilas

Water / fuel expansion with temperature may not be the major contributor to the increased pressure. Check out Boyle's and Pascal's laws. The pressure or volume of a gas increases with temperature.

Tony,

I know the pressure or volume of a gas increases with tempeture. The statement that I am refering to said that the pressure will change if the volume of fluid in the tank changes with the same rise in temp. I know these numbers are not accurate, but this is a example.
Water 110c
50%full tank=20.779psi
90%full tank=30.000psi

Wether it is 50% full or 90% full volumic expansion from tempeture is not going to be a factor. because the liquid is going to start turning into the gas phase and pressure will stabalize based on tempeture. But if it is say 95-100% full then Volumic expansion could be a factor. I understand that now and am curious how to calculate that pressure due to increase. I am also curious of an expansion rate or factor for the oils being measured. And possiably methanol. It could be slightly intresting to know since I buy methanol in 275 gallon tote tanks and I store it in 55 gallon drums when I get home. If I fill a drum when it's 38F and it is not opened again until it is 90+ there could be some pressure and spilage. If it gets left in the sun and the temp gets to 160F it could be very bad.

Logan Vilas

Last night when I was doing my water pre-wash and I was adding the hot water into my steel water heater processor and I forgot to open the top valve which vents to the outside of my building and the pressure relief valve (30 PSI) I got from Graydon triggered and shot a couple of quarts out. It really scard me at first thinking one of my hoses ruptured but I was glad to know what it was. That just goes to show you using a steel water proscessor tank with the correct relief valve adds safety. I do want to thank everyone out there for starting me off on the right foot.

Hello Logan Villas

You said that you buy methanol in 275 gallon tote tanks. Are these tote tanks metal or plastic?

Hello Gary,

If you vent to the outside there is no need to have a valve on the vent other than perhaps keeping bugs out of the reactor between batches. A bit of mesh on the outside opening would stop that.
Of course if you are using the reactor as a still you will need to be able to close the vent.
It sounds like your pressure relief valve discharges into your work area. A couple quarts of methanol shooting out of the safty valve into your work room is not desireable.
It would be safer to have it vent to the outside too.

Also, if you are pressurizing your reactor metal plumbing is less likely to rupture than Rubber/Plastic hoses.

Having seen the higgeldy piggeldy design of some of these reactors with a myriad of valves everywhere, I suspect a lot of valves are put in the wrong position from time to time.
A written checklist like pilots use would probably be beneficial and a lot safer.

quote:

Originally posted by Garybio:
Last night when I was doing my water pre-wash and I was adding the hot water into my steel water heater processor and I forgot to open the top valve which vents to the outside of my building and the pressure relief valve (30 PSI) I got from Graydon triggered and shot a couple of quarts out. It really scard me at first thinking one of my hoses ruptured but I was glad to know what it was. That just goes to show you using a steel water proscessor tank with the correct relief valve adds safety. I do want to thank everyone out there for starting me off on the right foot.

quote:

Hello Logan Villas

You said that you buy methanol in 275 gallon tote tanks. Are these tote tanks metal or plastic?

They're plastic With a metal pallet and metal cage. I had to buy them myself. They fill it for me. I can get it filled in any quantitys i want, but since I drive about 50 miles to get it and it sloshes a lot if the tank is low I have them fill it up.

Logan Vilas

Logan , remember that once water boils a gallon of water , 231 cubic inches , has the potential to become 254,100 cubic inches of steam . Water turning into steam expands 1,100 times the original volume . That is what makes steam dangerous . I have worked around 600 lb steam lines , believe me you are very careful when working with that kind of stored energy . Dan

quote:

Logan , remember that once water boils a gallon of water , 231 cubic inches , has the potential to become 254,100 cubic inches of steam . Water turning into steam expands 1,100 times the original volume . That is what makes steam dangerous . I have worked around 600 lb steam lines , believe me you are very careful when working with that kind of stored energy . Dan

Dan,

I'm not trying to be mean but what does that have to do with my question in any way shape or form?

When dealing with steam there is a direct ratio of steam temp to steam pressure. That ratio of temp to pressure will not change wether there is 1% water 50% water or even 99% water in the container.

From your earlier post I came to realize that volumic expansion from tempeture rise happens with a liquid. I knew that already but just had never thought about it causing pressure in a closed vessel. It works just like putting a coke in the freezer. there is a volumic expansion due to the water expanding at low tempeture which causes a pressure rise and the resulting damage to the can.

My main question is does anyone have an liquid expansion rate on methanol and any common vegetable oils. I am also curious how one would calculate the pressure buildup if a container was filled at 100% with water at 40F. Then the tempeture of the container was raised to 211F.

Logan Vilas