Dogma,

if that were true, and you weren't just making an armchair argument, then fire protection laws everywhere would stipulate that DIESEL and other flammables/combustibles be stored in plastic- firefighters don't always know when a structure fire they're responding to may contain a steel home heating oil tank (essentially same as diesel fuel, and much more flammable than biodiesel). This doesn't mean that they expect BLEVE (what you're describing, "boiling liquid expanding vapor explosion") every time they respond to a fire in a home with a home heating oil furnace.

But farmers, heavy equipment operators, homeowners with a home heating oil tank in the basement, etc, are forced by code (I think) to store the dangerous fuel in metal tanks, similar to what we're likely to use in small-producer biodiesel.

Methanol, by the way, is treated much like gasoline by (residential) fire protection code- the vapors behave similarly.

I fired off an email to my contact at Olympia Fire Department, asking her to take a look at this thread.

Mark

quote:

Originally posted by graycenphil:
Quote: (I know of no fires started by a sealed metal processor!)

There was a fire in Staten Island, NY at a biodiesel proccessing plant with metal tanks.

One tank had a leak and they were grinding down the metal to repair the leak. Sparks from the grinder ignited methanol fumes and the tank exploded. The worker was killed.

That was a welding accident, not a biodiesel accident. The weldor was repairing a 1,000 gallon tank full of glycerine that contained some methanol and methanol vapor. Again, the scale is different, I was talking about plastic homebrew processors versus sealed metal homebrew processors, where we have 40 gallons of this or that, which is a slightly different situation than 1000 gallons at a permitted production facility where the (outside contractor, I believe) repairman wasn't trained properly in what he was working on.

Welding accidents involving repairs of tanks happen all the time- and it was very unfortunate that this took place at a well-intentioned commercial biodiesel production company.

The point that everyone can agree upon is that if you have a large volume of stuff that can burn and you have it stored in ANY tank, is that it should be stored appropriately far away from potential sources of fire, and material which can burn. This is the common sense that governs where commercial/industrial users lay out their plot plans (or should) and it should be the same advice that the home biodieseler should follow. People should not think that "just because its in a steel tank", that everything is going to be cool and safe.

Beyond that, what its stored in, becomes an issue of structual integrity and material compatibility. Those tanks in basements that hold #2 fuel oil - those are not fire rated and yes, they do go *boom* and they have killed fire fighters (and people to).

My point, not my recommendation, is that in a fire a steel "tank" can and will explode (if exposed to flame for a long enough time), whereas a plastic tank will never explode (because the plastic will melt, then promptly dump the fuel all over whatever is near it).

quote:

repairman wasn't trained properly in what he was working on.

I'll totally agree with you there. There are very specific API guidelines for welding on tanks that have flammable liquids in them.

10 bucks says he was working at or above the liquid level in that tank. (as opposed to 2 to 3 feet below the liquid surface level)

Dogma,

fire codes disagree with you on the safety of this. otherwise heating oil could be legally stored in plastic tanks, which I"m pretty sure it can't (legally).

Your point about keeping tanks of combustibles away from burning walls, etc, is supported by codes that regulate commercial and industrial zoning- if you've got a petroleum refinery, you have much more stringent fire ratings for the walls that the petroleum refinery is made with, and inspectors are supposed to keep you from storing a bunch of garbage in teh way of the fire exit for example.

But we're talking about the safety of homebrew, small-scale biodiesel production, in residential zoning usually, which usually comes down to:

a. processors built out of barrels
b. plastic tanks like the Fuelmeister etc
c. processors made from water heaters
d. processors made from air compressors
e. processors made from old propane tanks

We already know that:
a. most barrels will just unroll, or, if they have a lid, the lid might fly off (bad, but not the same thing as shrapnel in all directions)
b. processors from water heaters can fall over and survive the fire intact, assuming there's no plastic plumbing in the system and you are in a habit of closing all the manual valves anytime you're not watching the processor
c. plastic tanks will melt even if fire gets nowhere near them, as evidenced by the photo at the beginning of this thread, which means that if there's fuel in them, the fuel will make sure the fire gets more serious
d. processors made from decommissioned propane tanks will probably be at least as sturdy as water heater-based processors
e. processors made from air compressors are probably similar to water heaters, and can probably handle a lot of pressure.


And, yes, we're talking about several different sizes of operations here, and several different types of hazards.

Ok.

Now, i'm going to go ahead and eat crow. I did the math - even taking into consideration coefficients of expansion and the combined gas law.

If you have a hot water heater filled to 70% or less (with oil), it is EXTREMELY unlikely that you will have an explosion (or rupture) on the tank with any reasonable HOUSEHOLD structural fire. (under these conditions even if you somehow managed to get the entire contents of the hotwater heater up to 800C (not going to happen unless you keep adding fuel to the fire) the maximum pressure you should see is about 50psi - well within a hotwater heaters pressure rating).

Everything I said though, still applies IF you were really dumb and had the thing full or very nearly full.

So, go ahead and beat me over the head now - I deserve it. I already agree'd with you on the other stuff.

quote:

Originally posted by RickDaTech:
Dropout,

The personal methanol sensors that have an alarm that goes off when you exceed safe dosage cost $300+ and have an expensive cartridge that is consumed and needs to be replaced regularly.

The fixed sensor systems that connect to automation equipment (computers) is gennerally $3000+

Gas monitoring Badges are available in methanol:
here for $130 for a box of 10 badges.

Hi Rick

Any contact info for the sensors?

Hi,

First, I would like to send my condolences to sunbreakbiofuels for the loss.

I won't debate that steel could be safer than poly in certain situations.

I have a couple questions.

1. Were those cone shaped tanks open at the top? If not, how far from the top was the liquid level?

- It appears that the liquid in the tank(s) was burning from the top and as the liquid level was consumed the plastic simply melted down to the liquid level... and so on. Yes, thereby feeding the fire.

2. Are there wide angle shots of the entire room?

- If the fire vented (through the roof) by itself rather quickly, heat stratification would have been eliminated and I think the temp in the room at the level of the box would have been more like 200 degrees F. That's one reason why the paper didn’t burn.

These of course, are all points of fodder. The important thing is to educate the fire service or the bio-d community will have over-regulation heaped on their heads. Also, any sensationalism by the press won't help.

C.

They were empty and not on fire - the fire was nearby, and the heat melted them.

Mark

Dropout,

They are really hard to find. I did find them using google (after several hours of tyring different keywords and digging through spec sheets), but didn't keep the links. The least expensive hand held versions were made by a German company. I was mostly looking for handhelds, so I didn't pay much attention to the ones used in automation.

The most common type of sensor it the combustible gas sensor, which will detect methanol, usually once the conentration reaches the LEL.

What you have to do is to get a single gas detector custom fitted with a methanol sensor. To find out which single gas detectors have optional methanol sensors you have to go to the factory page and dig through the spec sheets.

... well I went and looked. Here is one that is available with a methanol sensor.
Pac II Single Gas Detector

Damn! This is one fine thread!

Mark, you're right, this (and all the technical stuff in it) belong in an article on CBT...any takers to start writing it?

Just a comment on steel tanks (dawning a fire-retardant forum vest)....

A- If a water heater were full of oil, heck, let's say Biodiesel.
B- If it were sitting in a garage (where most homebrewing is done)
C- If the garage caught fire....

If said water heater had a pressure relief valve on it, and let's say even a 30 PSI one on it like we all recommend, then during a fire....

Wouldn't it just release the pressure?
Even if it spit a little biodiesel while releasing the pressure and even if the biodiesel CAUGHT FIRE, it'd just be a LITTLE biodiesel catching fire.

In other words, instead of the whole tank doing a complete meltdown (like the plastic ones we saw), the water heater would stay rigid, maybe squirt out some biodiesel & maybe even catch it on fire, but definately not go "BOOM".

Now, if this were the case, the fire would:
A- Cause the pressure relief valve to go off squirting A MINIMAL AMOUNT OF BIODIESEL out
B- The water heater would remain rigid and keep the REST of the biodiesel from going up in flames
C- The majoritiy of the fuel (Biodiesel) would remain stored in the water heater & not feed the fire near as much as the plastic tank which would've melted by this point feeding the fire.

As an example, I present exibit OB1 Canola:


I think that any bio that was in his tanks just kind of leaked out the pressure relief valve, but notice that the tanks are still intact. Nothing went BOOM. No "Appleseed bombs" occurred.

This too was a structure fire unrelated to the biodiesel processing (a big pot of oil spilled over on the stove & caused a "kitchen fire").

Also, can anyone tell us if in big, production areas, wouldn't a big stainless steel tank have a pressure relief valve on it?

I dunno, if it were my garage (and I sure hope it never is)....I'd prefer my "tank of biodiesel" to be sitting in a nice, insulated, steel encased, pressure relieved metal tank vs. a plastic, uninsulated, non-pressure relieved HDPE tank that'll melt a heck of a lot sooner than the steel one will.

Thoughts?
-Graydon

Thanks Rick

The key is "must have a pressure relief valve".

Otherwise, ANY vessel, that is made to hold pressure can become a bomb - given the RIGHT circumstances.

The math I did that proved that hot water heater would be "safe" (i.e. not a bomb) was done assuming that it was 70% full and at room temperature. If I had said that it was 90%+ full, then, most likely it would not have been a safe scenario.

The other thing to remember, is that though the pressure relief valve will probably keep the vessel in tack, it doesn't necessarily limit the amount of biodiesel/vegetable oil that would be consumed in a fire situation. Here's that scenario.

Pressure increases to 30psi
Pressure relief valve opens, spewing a little biodiesel.
Pressure relief valve closes.
Tank heats up, pressure goes up, pressure relief valve opens spewing a little more biodiesel.

This will continue adnauseum until the volume in the tank drops to such a level that at whatever the temperature of the fire is, the equilibrium pressure of the vessel will be less than the setpoint for the relief valve.

The other scenario, is that even WITH a pressure relief valve, if the tank is full enough, then the pressure relief valve may not (again, under certain circumstances) be able to limit the rise in pressure fast enough to prevent overpressurization of the tank - remember, this relief valve is suppose to protect the hot water heater from itself - NOT from a external fire which is now being fed by biodiesel spewing out of the relief valve.

more later.

Since I was the goat on this one, I'd be happy to contribute however i can.

Thanks!

Earlier I had mentioned pressure testing a 55gal barrel. I've taken pictures for you all to look at.

The barrel blew at somewhere between 70-75psi.

Based on the previous post by Dogma, I would assume that you would never see pressures this high.

I was looking over my methanol barrels this morning in the opposite building and did notice that the barrels had "buldged" a little bit. So even at 30ft from the fire there was enough heat to cause the contents to expand a little.

BTW: A 55gal barrel is built to withstand alot of abuse. You shouldn't compare the integrity of a 55gal drum to a 5gal metal container.

--
Jeff Brandt
Sun Break Biofuels, LLC
jeffb at sunbreakbiofuels.com

Almost forgot to mention,

When that barrel finally popped, it launched into the air, and after bouncing once, rested over 70ft away from where it had started.

The top shot out into our forest like a frisbee and has never been found.

--
Jeff Brandt
Sun Break Biofuels, LLC
jeffb at sunbreakbiofuels.com

Jeff,

Great Pictures!

It is possible to see 75 psi in a drum processor if it is sealed when the element dry fires, igniting the methanol fumes inside. There are at least a couple of drums that were processors that are now in the same condition as your drum. If they have a good vent they stand a chance of keeping the lid in place. The biggest danger is being in the path of the lid when it pops.

We gennerally rig a 30psi relief valve on the water heaters. The stock water heaters have 150psi relief valves on them. So from the factory they can handle 150psi without any issues. I think they are designed to withstand something like 300psi.

dogma,

Most of us strongly recommend that people plumb their presure relief valve outside and away from the processor. If they do it copper or steel, then the biodiesel or WVO wont end up heating the tank, and possibly not even be involved in the fire.

To throw fuel on the fire:

NREL (National Renewable Energy Laboratory) guide for "biodiesel Handling asnd Use Guidlines" states, "Acceptable storage tank materials include aluminum, steel fluorinated polyethylene, fluorinated polypropylene, and teflon."


The other big bonus is heavy duty plastics is that they are much cheaper so the money you save you can add to a fire suppersion system. Then it would be safer than a steel tank.

quote:

Based on the previous post by Dogma, I would assume that you would never see pressures this high.

That calculation result was based upon a hot water heater that was 70% full. Changing this to 90% full makes the final pressure rise much more dramatic, in fact, probably catastrophic.

Here is the data for initially 90% full:
T1 = 200C, P1= 25.83psi
T2 = 400C, P2= 43.05psi
T3 = 800C, P3= 103.75psi

Here is the data for initially 95% full:
T1 = 200C, P1 = 30.13 psi
T2 = 400C, P2 = 66.43 psi
T3 = 600C, P3 = 190.9 psi, vessel fails
T4 = 800C, P4 = vessel solid, vessel fails

As you can see, this is a exponential curve. Once the vessels gets near solid / solid things start happenning very, very quickly.

just some more numbers and a reason to make sure that #1 you have a relief valve and #2 that you test it and make sure that it actually works. I've seen very large compressors blow up because relief valves were not able to relieve at full capacity.