How long to hold reactor at 55deg

[curnow Biofuels Forum Newbie Find all posts View Profile Close curnow]

G'Day gang,
How long does the reaction tank need to be held at 55deg when the methoxide has been mixed in?

Cheers

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: How long to hold reactor at 55deg

Hi curnow,
As long as everything remains liquid the reactor does not need to be held at any particular temperature for the reaction to occur.
Length of time for the reaction to run depends on a number of variables such as temperature, amount of chemicals, mixing vigor and etc.

[WesleyB Donating Member Find all posts View Profile Close WesleyB]

Re: How long to hold reactor at 55deg

I just read that as a rule of thumb for every 10 degree centigrade increase in temperature the reaction rate is about twice as fast. That might apply to the biodiesel reaction also.

[Bueff Biofuel Enthusiast Find all posts View Profile Close Bueff]

Re: How long to hold reactor at 55deg

Hi Curnow,

depending on the method you are going to use, if you do the "normal" method, you heat the oil to about 50 deg c mix the methoxide in and let it mix for about an hour, thats it. Although the mix will still react if you leave it sitting over night or longer, so a good insulated tank would make sense if you are going that way.
Recently I spoke to another member and he does a acid reaction, he mixes 20% methanol and the acid (can't remember the percentage) and then holds the temperature for 3 day on a 1000l batch while a paddle stirrer on a timer mixes the lot every now and then, after 3 days he adds the methoxide and finishes the reaction.

hope that makes sense

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: How long to hold reactor at 55deg

Hi Bueff,

Although the mix will still react if you leave it sitting over night or longer,

If you are talking about the Base stage, when you stop mixing, the glycerine/methanol/ caustic quickly settles to the bottom of the container and that is pretty much when the reaction stops. None of the testing I have ever performed has showed a continuation of the reaction after this point.
It is true that the "glycerine" will continue to settle out over a period of several days/ weeks but this is not a continuation of the reaction.

[curnow Biofuels Forum Newbie Find all posts View Profile Close curnow]

Re: How long to hold reactor at 55deg

Thanks Gang,
The reason I ask is I have a second hand processor and it looks like the batch was pumped to another settling tank. I would like to do the same as the reaction tank is not set up for easy glycerine/bio extraction.

Thanks again.
Cheers

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: How long to hold reactor at 55deg

Hi curnow,
when you pump the contents of the reactor to the settling tank the reaction stops at that point. Therefore you need to be sure you have achieved the amount of reaction that you want to achieve before pumping to the settling tank.

As Bueff has pointed out, "common knowledge" is that at around 50 deg C the reaction takes about 1 hour in the reactor to reach completion. Some reactors will achieve that and some reactors require more mixing time depending on...

What type of engine will you be using your biodiesel in?

[curnow Biofuels Forum Newbie Find all posts View Profile Close curnow]

Re: How long to hold reactor at 55deg

Thanks Tilly,
The agitation is by a pump circulating the oil from bottom of tank to top. Is this the best way to do it or is a paddle/prop more efficient?
The biodiesel will be mainly for a Landrover Discovery 300TDI so I don't think there will be issues. I do plan on washing as well, although the guy I bought the processor off never did.

Cheers

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: How long to hold reactor at 55deg

Hi curnow,

Thanks Tilly,
The agitation is by a pump circulating the oil from bottom of tank to top. Is this the best way to do it or is a paddle/prop more efficient?

Both methods work. I have been told paddle/ prop mixing gives better mixing for the same amount of energy used. I do not know.
If your reactor is a water heater then pump mixing is about the only way to go. Many people successfully use pump mixing in a water heater.
If you have an removable top on the reactor such as a 200 litre drum then both ways work. I use a paint mixer in my reactor.

Just a word of caution, if you have a water heater reactor with the heating element still installed for heating, do be aware that there have been MANY reports of explosions due to turning the heater on when it is not covered with a liquid. After you make your first batch of biodiesel in a water heater the atmosphere in the reactor is always explosive. If you turn an uncovered heater on, the heating element quickly exceeds the self ignition temperature of methanol and BOOM.
On the plus side, there have been no serious injuries reported from this that I am aware of and the heating element is usually not damaged.

The biodiesel will be mainly for a Landrover Discovery 300TDI so I don't think there will be issues. I do plan on washing as well, although the guy I bought the processor off never did.

I can not comment on the Landrover. Someone here might have more information.
I no longer use water washing either.

Cheers[/QUOTE]

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: How long to hold reactor at 55deg

G'Day gang,
How long does the reaction tank need to be held at 55deg when the methoxide has been mixed in?

Cheers

Actually it doesn't even need to be heated to 55 degrees at all (according to tillyftromparadise on another thread). Tilly from paradise assures us that it will proceed even if it has been placed in a fridge (at 5 degrees). So all that money you spent on a heater is wasted.

That's right isn't it Tilly?

BTW, when ARE you going to modify the Dr Pepper method to explain to people that you don't need to heat the mixture. Look at all the people you are confusing.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: How long to hold reactor at 55deg

Hi Mark,
You have certainly been busy on this forum this afternoon.

Actually it doesn't even need to be heated to 55 degrees at all (according to tillyftromparadise on another thread).

Mark is correct here

Tilly from paradise assures us that it will proceed even if it has been placed in a fridge (at 5 degrees). So all that money you spent on a heater is wasted.

Heaters don't cost that much. I got my out of the rubbish tip and attached a spare cord to it that I had cut off a defective iron.


\

That's right isn't it Tilly?

It depends on why you want to heat and what you mean by wasted.
A lot of people heat the oil to remove the water.
Also, as WesleyB has explained several times, the warmer the reaction, the faster it goes.
If you do not want to heat your oil to remove water and it does not bother you to run your reactor for 8 or more hours then you could probably think of the heater as wasted money

BTW, when ARE you going to modify the Dr Pepper method to explain to people that you don't need to heat the mixture. Look at all the people you are confusing.

I am sure that not every facet of biodiesel production is covered in my World Famous Dr Pepper Technique (Pat Pend)
If you tell me which part is confusing you I will try to help you better understand.

If I can provide you with any further help just ask. I have a lot of experience.