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Biodiesel => Biodiesel equipment => Topic started by: nathanrobo on April 29, 2013, 12:29:00 PM

Title: Eductor positioning
Post by: nathanrobo on April 29, 2013, 12:29:00 PM
Trying to work out the expansion of oil from cold (15 deg c?) to 70 deg C.  to figure positioning of eductors.

The tank is 500.9 to the top of the inspection opening, 491.1 litres to the top welded seam, 435.21 excluding cone, 56 litres in the cone and 4.3 litres for every 10mm. 

Based on 380 litre batches and  18% meth x 90% for the first reaction (61.56 Litres) plus a bit for KOH?? Plus a bit for expansion??  So any ideas as to how much volume the 7 grams x 380 litres of KOH adds to 67 litres of meth? 

So far the best I can see ref the thermal expansion coefficient for oil is 1 deg for every 14 deg c increase - is this correct? This being the case I would expect to see 3.93% expansion between the values above would be about 15 litres or apprx 35mm?  or about 80mm below the level of the top welded seam?  If this is correct so far, I just need to add in for the KOH - any ideas?

might seem a stupid question, but I assume all of our calculations are base on hot or cold oil?  I've always calculated on the basis on hot oil, but maybe that's wrong and would mean about 105 grams KOH too much in the first batch.
Title: Re: Eductor positioning
Post by: Jamesrl on April 29, 2013, 01:53:08 PM
If you post me the exact dimensions of the reactor I'll work it out for you.

BTW do all your measuring cold and ignore any expansion, to measure hot can result in an over dosing catalyst.   
Title: Re: Eductor positioning
Post by: Head Womble on April 29, 2013, 06:47:00 PM
Oh dear, I measure my level when hot as this is the only time you have a known volume all year round.
Title: Re: Eductor positioning
Post by: Jamesrl on April 29, 2013, 06:55:10 PM
Oh dear, I measure my level when hot as this is the only time you have a known volume all year round.

Is an expansion graph a straight line then?
Title: Re: Eductor positioning
Post by: bertle on April 29, 2013, 07:40:01 PM
If you post me the exact dimensions of the reactor I'll work it out for you.

BTW do all your measuring cold and ignore any expansion, to measure hot can result in an over dosing catalyst.

From memory Nathan's is 740mm diameter, the height of the cylinder is 1m with a 45 degree cone on the bottom and a 10 degree cone on the top. Steve's is the same but 700mm diameter.
Title: Re: Eductor positioning
Post by: Head Womble on April 29, 2013, 07:41:04 PM
Oh dear, I measure my level when hot as this is the only time you have a known volume all year round.

Is an expansion graph a straight line then?

I have no idea, but at 60° you allways have a known volume,
whereas we could have an ambient temperature swing of some 40° between summer and winter,
so filling at ambient and then heating will give an unknown volume once at 60°.

I'm not saying I'm right, but it works for me.
Title: Re: Eductor positioning
Post by: nathanrobo on April 29, 2013, 09:32:31 PM
If you post me the exact dimensions of the reactor I'll work it out for you.

BTW do all your measuring cold and ignore any expansion, to measure hot can result in an over dosing catalyst.

Thanks James, I'd often wondered about that... it was on my list of stupid questions to ask (and then sit back and wait for the abuse).

I see Andrew's posted the dimensions, for both reactors - pretty please  ;)
Title: Re: Eductor positioning
Post by: Jamesrl on April 29, 2013, 10:49:41 PM
If you post me the exact dimensions of the reactor I'll work it out for you.

BTW do all your measuring cold and ignore any expansion, to measure hot can result in an over dosing catalyst.

From memory Nathan's is 740mm diameter, the height of the cylinder is 1m with a 45 degree cone on the bottom and a 10 degree cone on the top. Steve's is the same but 700mm diameter.

Why for you no make them both the same, awkward git.

What's the dimension from the inner cone top edge and the top of the cylinder?
Title: Re: Eductor positioning
Post by: bertle on April 30, 2013, 06:34:58 AM
They are not both the same because Steve's shed door is not as wide as Nathan's, mostly because Nathan has not built his shed yet.
The plain part of the cylinder from cone weld to cone weld is 1m.
Title: Re: Eductor positioning
Post by: nathanrobo on April 30, 2013, 08:02:34 AM
They are not both the same because Steve's shed door is not as wide as Nathan's, mostly because Nathan has not built his shed yet.
The plain part of the cylinder from cone weld to cone weld is 1m.

The shed is coming on... One course of thermalites and a few courses of brick to do to the wall plate, plus the gables at either end.  Looking for a 2.1mtr 50mm cavity lintel (if anyone has one going cheap) for the french doors. 
Title: Re: Eductor positioning
Post by: thewormman on April 30, 2013, 10:08:12 AM
it was on my list of stupid questions to ask (and then sit back and wait for the abuse).


Better to ask a question and get some sarcasm and then do it right. Rather than to just do it, screw it up and get destroyed by the pi$$ taking 

NO-one is perfect not even Jim despite what he constantly tells everyone.  ::)

IMHO of course :)
Title: Re: Eductor positioning
Post by: Jamesrl on April 30, 2013, 10:19:52 AM

NO-one is perfect not even Jim despite what he constantly tells everyone.  ::)

IMHO of course :)

Oh yes I am, my mum told me I was and my mum was ALWAYS right, it's genetic you see.

Like if your parents didn't have children there's a very good chance you won't have any.
Title: Re: Eductor positioning
Post by: Jamesrl on April 30, 2013, 10:34:30 AM
The plain part of the cylinder from cone weld to cone weld is 1m.

Just so I can get it clear in my mind, is the 1m weld to weld the inner or outer cone weld?
Title: Re: Eductor positioning
Post by: thewormman on April 30, 2013, 12:42:57 PM

Like if your parents didn't have children there's a very good chance you won't have any.

Cant argue with that sort of logic... (http://serve.mysmiley.net/rolleye/rolleye0007.gif)
Title: Re: Eductor positioning
Post by: bertle on April 30, 2013, 12:58:02 PM
The plain part of the cylinder from cone weld to cone weld is 1m.

Just so I can get it clear in my mind, is the 1m weld to weld the inner or outer cone weld?

Inner cone. The dimensions I have given are for the main tank and ignore the second cone.
Title: Re: Eductor positioning
Post by: Jamesrl on April 30, 2013, 01:25:25 PM
Cheers Andrew.