Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Bio-boy on July 12, 2015, 10:23:26 AM
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I hope it takes longer to heat water than it does oil!
I tested my new processor for leaks yesterday using water to prevent making a mess should there have been any issues.
I then decided to see how long it would take to heat the water to 50deg.
It took an age to get up to temperature. I may need to revisit my design and add an additional heat source.
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Eeeeeeer, it takes longer to heat oil as it doesn't absorb heat as quickly.
It's not the heat source you need to look at it's your insulation, we all use the same elements as you so that's not the problem.
Did you have the pump running whilst heating? Liquids appear to heat up faster when agitated.
Have you turned the immersion stat to max, have you re-ranged the stat?
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I disagree with Jim. :o
Oil has a lower specific heat capacity than water (actually, most things do - that's why we use water in cooling systems) therefore for any given heat input (normally 3kW for the elements we use) it takes less time to achieve the same temperature as it would with water.
edit: Curious, so looked it up:
Water is 4.2 kJ/Kg/degree C. Vegetable oil is 2.0 kJ/Kg/degree C.
In a perfect plant with no losses and assuming a constant rate of energy input, oil will take just under half the time of water.
Although at any significant temperature above ambient you'll have losses to the surrounding environment to deal with. Ensure it's insulated well!
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What volume are you dealing with, and what heater?
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I don't know about specific heat values just heating liqiids in a drum.
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Surface area of the element also helps with heat transfer. An 18" 3kw element will heat liquid faster then an 11" 3kw element.
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On a personal note I would say heating a 200litre batch with one 3kw heater is tolerable (time wise)
Anything bigger really needs more heat.
When I used my 400litre processor and only used one immersion it took forever to heat, especially in the winter.
Nowadays for anything greater than 200litres I use the M67. It's quicker and a damn site cheaper.
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Whats an M67???
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Surface area of the element also helps with heat transfer. An 18" 3kw element will heat liquid faster then an 11" 3kw element.
Mines a 27" element. It maybe worth fitting 2 of them.
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Surface area of the element also helps with heat transfer. An 18" 3kw element will heat liquid faster then an 11" 3kw element.
I've never compared them side by side, so there might be something funky going on, but it shouldn't make a difference.
3kW is the same amount of energy going in regardless of element size.
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Whats an M67???
https://www.youtube.com/watch?v=0f7p4fxgkgw
Or, BB, Or, just react at ambient especially at this time of year, works fine.
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On a personal note I would say heating a 200litre batch with one 3kw heater is tolerable (time wise)
Anything bigger really needs more heat.
When I used my 400litre processor and only used one immersion it took forever to heat, especially in the winter.
Nowadays for anything greater than 200litres I use the M67. It's quicker and a damn site cheaper.
Totally agree with this. The biggest difference to processing for me was using a 45kW oil fired boiler. 200 litres from cold to reaction temperature in about 20 mins.