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Processor materials for AE
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Ive been making biodiesel from low titration oil for four years but now I have some high titration oil 9,5ml koh. I tried to process it with glycerol pretreatment and 2 stage processing but it failed to convert. I think if I am going to regularly this type of oil I will need to use AE.
Ive read up on Dkennys method and I think Ive got a good understanding of it although I may have some questions as I go along.
My main concern is the effect the acid will have on my processor. It is a mild steel tank with brass plumbing fittings and pvc pipe. It uses a standard central heating circulation pump. Will these components withstand the acid process?
Would it be better to heat the oil in the processor and then pump it into an insulated plastic barrel, add the acid, mix it mechanically until it is done and then transfer it back to the processor for the base stage.
Would it be safe to reheat the oil using a 3kw immersion after the acid stage?
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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my old processor was mild steel, after five years of AE/base/base processing there was no indication of any corrosion what so ever. all plumbing on that processor was copper, the valves where brass and circ pump was one designed for hot water circ (heating), the plastic tank would also work but remember the AE process nedds heat the reaction will stop oncetemp drops below about 90f. I have electric heaters installed in my processor so reheating is not a problem.


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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I would think the temperature limit for the PVC will cause you more concerns.

I used std black iron for a long time before I had any problems..keep in mind lots of oil that I processed was far worse( think 30+ KOH)..it slowly corrodes from the inside..this create small leaks..but they still make a mess. most damaged happened where the oil mix might encounter high turblance..T's and elbows..to date I've only had one problem with a short pipe..if you saw the setup the failure point makes more sense..the pipe has a large vibration load because I don't the piping supported as it should be..hey its was in used for since I put my appleseed together..I'm not complaining..

for reheating..make sure you keep it mixed..or make sure the surface temps of the element are low. if you run in air without burning up you should be fine without mixing

if you have to have plastic..look into using PEX..it has higher temp limits than PVC..and is chemical resistant.

if you have money..think stainless 316l or other acid tolerant metals hastaloy ( sp)..please sit down before you look it up..if you think 316l is pricey.

-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
2006 Jeep Liberty CRD Smile - the wife's
99 dodge 2500 5.9l 24v..-mine Smile
everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post
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The pipe work on my processor is pex and is rated to 85 degrees C so it should be all right. Stainless pipe is available here at just slightly more than pex and a lot less than copper. Its the fittings that are expensive, about 10 times the price of brass. From what you say it would seem that my processor will be ok as is. The oil Ive got is titrating at 9.5 so its not as extreme as some of the oil you have treated. I hope to get my sulphuric acid this week and do a small 2 litre batch this weekend.
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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I thought I read that you have PVC not pex..
if its PEX you should be fine for normal AE process..HTAE..165F + I would a little more concerned.
if you want to be sure..take a piece hit it with a hammer. PVC will break pex will bend. Here in the US Pex can be bought in coils. I don't think I ever seen pvc in coils other than the clear tubing.

HTAE..runs higher temp and shorter AE processing times. great for higher T oil..I'm thinking T20 or higher..it should work with lower, but why? with T's under 10 you might need to run for 3-4 hrs. no big deal. with an insulated reactor you could turn off the heater.

-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
2006 Jeep Liberty CRD Smile - the wife's
99 dodge 2500 5.9l 24v..-mine Smile
everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post
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As a first entry into acid/base processing I decided to set up a 10 litre processor rather than risk a full 150 litre batch. I got a 15 litre plastic tub with a tight snap on lid and placed it in a metal basin of water. The basin sits on my gas ring. I filled the tub with 10 litres of oil that titrates at 7.5 koh and heated it up to 65 degrees C. I added 10ml of sulphuric acid to 1.2 litres of methanol, mixed it and added it to the oil. I stirred gently for an hour and did the titration test, no change. I stirred more thoroughly for another hour, only half a ml reduction.
At this stage I was a bit disgusted and went off and did something else for 2 or 3 hours. When I tested it after that it titrated at only four! So I reheated it and continued to stir it occasionally for about 2 hours. Ive stopped now and I will test it again in the morning. With luck it will be 3 or even 2.5 and I can do the base stage.
I have a question for the experienced AEers. Is it possible to process with acid for too long, can the process reverse like the base reaction or does it simply stop?
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post



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Is it possible to process with acid for too long, can the process reverse like the base reaction or does it simply stop?

NO. I've let an acid batch sit for a week in the processor. once the heat is gone (less that 100f the process stops.) the good thing is simply reheat and mix and it starts up again. What was the total time for this AE. don't be too concerned if you have an ae that doesn't work, it happens but nothing is lost other than time to figure out what went wrong. most common problem is wet oil, but you only have to add more acid to overcome that. the draw dack of adding too much acid is that when you add the caustic in the base stage the acid is neutralized and in that reaction h2o is produced.


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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