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You want to make Biodiesel?


JimAttrill
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This gave me a bit of a shock as I used to work on RR Darts and RR Pegasus engines with WM injection with no safety clothing at all. This was in the sixties and seventies when things weren't as toxic as they seem to be nowadays. The title of the article is a bit of a misnomer as it is actually about the dangers of methanol.

The hidden danger in home biodiesel production

Dr Garth Cambray

Scientists follow basic safety guidelines in regulated laboratories but as a growing number of hobbyists utilise chemicals for anything from thinning paint to home alternative energy fuel production, accidents can happen if the science behind chemicals is poorly understood.

Many home producers of biodiesel are unaware of the dangers of their hobby. Methanol, an extremely valuable reagent in the production of many useful products and in processes such as biodiesel production, can also be dangerous in the wrong hands. This article shows why and how to mimimise some of the risks associated with working with this chemical. In a related article read about the chemistry behind methanol synthesis.

In the production of biodiesel there are two types of producers - large professional companies with carefully designed plants, and small hobby producers with home made apparatus. Both use similar recipes involving the reaction of methanol with vegetable oil and or animal fat to produce biodiesel. Methanol is a highly toxic alcohol, and, on a hobby scale many producers inadvertently expose themselves to methanol through inhaling small quantities of fumes, and occasional skin splashes. It is very important to understand that methanol vapour is very easily absorbed by the lungs - in addition to that, methanol condenses on the eyes and skin, leading to absorption this way. Protection from these fumes is hence very very important

To understand how methanol damages the body, it is important to understand the basics of alcohol metabolism in humans. Alcohols are simple chemicals consisting of a chain of carbon atoms with hydrogens around them and one or more sets of a hydrogen and an oxygen attached to one or more of the carbons. Once alcohol enters the blood stream from the gastro intestinal tract it passes through the liver. The dominant alcohol in alcoholic beverages is ethanol, an alcohol with two carbons and one oxygen bonded to a hydrogen - the liver detects the presence of ethanol easily and begins producing the enzyme alcohol dehydrogenase which converts ethanol to acetaldehyde. A second enzyme, acetaldehyde dehydrogenase, converts the acetaldehyde to acetic acid (vinegar). From this point the alcohol has been rendered relatively non-toxic and many metabolic pathways can continue the process of converting it into either energy or a storage molecule like fat.

As we have mentioned already, ethanol as an alcohol contains two carbon molecules in its backbone. Methanol contains one. The exact same enzymes which break down ethanol are able to break down methanol. However, the products of this process are far more toxic than with ethanol and the actual poisonous effects of methanol are from its metabolic breakdown products. Hence, methanol is first broken down to formaldehyde (highly toxic) and then to formic acid (highly toxic). Unlike the ethanol process, each metabolic step in this process is highly toxic and damages the liver.

The enzymes responsible for alcohol degradation have a higher affinity for ethanol than methanol - hence the rate of formation of toxic methanol metabolites can be reduced by co-administration of ethanol. This is a confirmed medical procedure in cases of methanol poisoning. Other chemicals such as Fomepizole have similar effects.

Hence if low concentrations of methanol enter the body, it is healthiest for the body if they are not in fact metabolized at all, but if they instead leave the body via the breath, sweat and urine. Hence a low background level of ethanol in the blood will help to stop the body metabolizing methanol and force the methanol to leave the body by other routes. In short however, it is just best not to have any methanol enter the body.

If methanol does enter the blood stream it causes liver damage, swelling of the retina of they eye (which can cause blindness), brain damage and a host of other highly unpleasant symptoms.

In biodiesel making catalysts such as potassium or sodium hydroxide are dissolved in methanol to form methoxides. Alternatively commercially produced methylates are added. Either way, these compounds are even more toxic than methanol and cause instant and painless nerve death upon exposure to the chemicals. Hence skin splashes will cause patches of skin with no feeling.

It is also very important to understand that methanol is a highly flammable substance. Methanol burns explosively, and a rule of thumb is if you can smell methanol in the air, there is a good chance that somewhere in the room enough methanol is present to cause an explosion. The flame can find methanol even better than your nose can.

To avoid these problems, it is advisable that anybody who comes into contact with methanol wear goggles (so that whiffs of methanol vapour will condense on the goggles not the eyes), gloves, a lab coat (cotton preferably as this will not burn as easily if there is an explosion), a gas mark which is rated to remove methanol vapour - note that normal activated carbon masks for removing organic solvents are not effective at removing methanol, and that a special methanol removal cartridge is required. All reactors should be rigged to vent methanol fumes into a place where they will not cause an explosion, or be inhaled by people. The biodiesel production area should have an open flow of air to ensure that the atmosphere in the room does not slowly accumulate methanol. If an extractor fan is used, it must be a spark free extractor fan.

In this way, the average biodiesel maker will live to see the effects of the global warming their fuel helps to reduce.

For anybody working in the laboratory, it is advisable to know what to do in the case of poisoning. The Merck Manual for Mobile Devices (also available in print form) is the best known global reference dealing with how different chemicals cause toxicity, and what to do about exposure to these toxins. Currently sold at a cost of US$49.99 for a years subscription, including bi-monthly updates, this reference is in some ways as important to a scientific organization as its computer anti-virus software - you never know what virus your computer will catch, and you never know what toxin you will accidentally poison yourself with, so in both cases, having access to a global network of experts who deal with these problems offers you and your colleagues a safer existence.

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Guest otchie1
This was in the sixties and seventies when things weren't as toxic as they seem to be nowadays.

Thanks Jim

My brother in law's dad was always poopooing dust fears as he'd been a carpenter all his life and never had any trouble. Used to even cut asbestos sheets with a saw; no bother.

Bother in spades now as he needs oxygen and can't get up stairs any more. :ph34r:

I wear an S10 :ph34r:

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I remember we used to get big drums of WM mix, 70:30 IIRC. The systems were horrible to work on as they had put a nauseant in the stuff to stop idiots from drinking it. We knew it would cause blindness and death if you drank it, but nobody warned us about the dangers of the fumes or skin contact.

The jet pipes on the aircraft were all lagged with asbestos cloth in those days. To this day I have asbestos flower pots and even two dog kennels made of the stuff, but as they are painted and I don't drill or saw them at all there is no dust. This country has a bad history of asbestos as most of it used to be mined here and the miners are still dying.

What's an S10?

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Guest otchie1
I remember we used to get big drums of WM mix, 70:30 IIRC. The systems were horrible to work on as they had put a nauseant in the stuff to stop idiots from drinking it. We knew it would cause blindness and death if you drank it, but nobody warned us about the dangers of the fumes or skin contact.

The jet pipes on the aircraft were all lagged with asbestos cloth in those days. To this day I have asbestos flower pots and even two dog kennels made of the stuff, but as they are painted and I don't drill or saw them at all there is no dust. This country has a bad history of asbestos as most of it used to be mined here and the miners are still dying.

What's an S10?

S10 also known as the FM12.

Pukka fit, comfy enough to wear whilst sweaty and easy to breathe in. Also keeps dust out of your eyes unlike most DiY dust masks. Last used to deal with sisters asbestos garage roof.

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Jim, what this means in our environment is ...... before you fill up with LRP fuel at a green or yellow pump (which contains potassium as an additive) you have to make sure you drink enough beer. If you don't die due to the accident caused by the alocohol you may live a slightly longer but horrible life whilst the methanol kills you.

Some alcohol makes you temporarily blind others make you permanently blind. Now we just need to know which one makes you the happiest on your way out. I've tried the temporary one and it made me happy. I did'nt even mind walking home :lol:

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I wondered that nobody had commented on this statement: "Hence a low background level of ethanol in the blood will help to stop the body metabolizing methanol and force the methanol to leave the body by other routes."

The good doctor does not quantify the "low background level", it must be low enough so that you don't fall in the biodiesel vat, but high enough to keep the methanol away. :)

BTW, the antidote to antifreeze (ethylene glycol) poisoning is also ethanol, so we keep a big bottle of vodka in the first-aid box. :D

I wonder what H&S would make of that!

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