first bio batch - some questions

[simonallen]

Hi Guys,
Part way through my first bio batch and have some questions if possible :-)

I dewatered the oil as I used to when filtering. Passed the hot pan test no problems. I am doing a batch of 120 liters. Used the two stage no titration calculator on here, which asked for 19.2 liters of methanol and 600 grams of KOH @ 5g/litre base.
Added this and had it mixing for an hour and a bit at reaction temp (its been sat at 65 degrees c). allowed it to settle and had about 8 liters of glyc drop out. This is where I left it last night. Came to it again tonight, and have checked for more glyc dropout which there was a nominal amount and got this into the container. I heated the oil back to reaction temperature and have done the 3/27 test, but i am getting 1.9ml dropout in this? I was under the impression that it should be less than this maybe? I ran the pump for longer to see if it changed things but its been pretty consistent.

The calculator has told me another 15.2 liters of meth and 380 grams of koh which I have mixed and added. I was under the impression that I should be using less chemicals than this? 34.4 liters I work out at 28.8% and I'm sure I have read of people completing the process with less than 20% methanol? And thats if I get a clear pass on this mix.

Also how much glyc should I expect to be seeing at the end of the process? Is there a set ratio of glyc/oil or does it vary wildly between batches?

Thanks in advance,
Simon

[Bio-boy]

It all depends on the quality of your oil in the first instance. The No-titration method doesn't mean less chemicals but is a means of getting a better conversion and is a more refined process. If using KOH I do stage 1 working with 7G base and 2nd with 5G base and I always get a 100% conversion with minimal soaps. As you gain more experience you will get a feel for it and will be able to reduce your chemical usage.

[simonallen]

thank you for the input, I think I will try with 7g on the first run next time. will this cut down a little on the methanol usage second time? I'm not worried about the amount of chemicals used, tbh I am doing it more of a hobby than a money saving excersize I just wnted to make sure I wasn't doing anything horrifically wrong. I run a 300tdi discovery which is quite happy on pure veg but I would like to run it the td5 once I'm confident in my process.

I have had the pump running with the second stage methoxide in for about 40 mins now and have just done another 3/27 test and have got a minute amount of dropout still but the methanol is still staying cloudy which I have read is a "pass with complications" - I am going to run the pump longer to try and get rid of the dropout and see what I can do about the cloudiness.

Do you have any tips bio-boy?
cheers 

[Bio-boy]

The 7g base will convert the FFA and then the final 5g will complete the conversion for you.

On a batch size of 130L i used to run my old processor for 1.5hrs for stage 1 and 1hr for stage 2.

Are you water washing?

If you are running a 300TDi I wouldn't get too hung up on getting a complete reaction as that will come in time and with experience.

Enjoy it, don't rush it and believe me it will not only be a hobby but also a considerable money saver.

[simonallen]

this is my 3/27 test after the second stage, I'm fairly confident i have a complete reaction now, so the panic was over nothing. is this cloudiness anything to worry about if I was to run it in the td5? it is a pump deuce engine so needs to be good bio to save on the bills lol.

Pretty chuffed how easy it is tbh, dare i say just as easy as filtering, and it will work in the winter too hopefully!

[Bio-boy]

A clear pass indicates at least a 98% conversion. You've done the easy bit, now you need to get rid of all the soaps and effectively dry your fuel. The 300TDi will run on anything however the TD5 will be demanding of high quality fuel.

Will you be water washing?

[simonallen]

Sorry I meant to answer that last time, I was thinking of bubble washing. I have compressed air in the garage, and although that sounds scary I can regulate it down way below the output of a fish tank bubbler. I have two of the sintered brass air tool exhausts into a T piece, and the third port will go to to the air supply.

I dont have the facility to mist spray as of yet, but only because I have been impatient and wanted to get a batch started (kid at christmas etc) and have a vast array of air tool stuff at my disposal.

[Bio-boy]

For a TD5 I would water wash as it will provide better quality.

[simonallen]

ok, thank you for that :-) I'll lay off the td5 untill I can mist it then.

Cheers!

[GedsJeep]

fancy wasting all that good oil on that bio crap

[dgs]

Simon,
You have ended up using 8.2gms of KOH/litre of oil which isn't bad at all. If you don't pre-treat your oil using a glycerol pre-wash you will never use less than the base amount. Theoretical amount is 7.7gms (allowing for the 90% purity) and this is assuming your oil contains no FFA's (which it will do)

The dropout test is full of anamolies. To get an accurate reading you must leave it at 20degs until the methanol phase is clear. The cloudyness could be due to glycerol and soap, so this will clear without creating any dropout, but if it is suspended oil (triglycerides) it will settle to the tube bottom and cause dropout.

As a rough 'normal' you will get about as much glycerol ex process as the methanol you put in.

I think you must have read the 2nd stage calculator wrongly? as the 24 litres or so of oil you had left unreacted after the 1st reaction should require a maximum of about 5 litres of methanol.

[Chug]

You ended up using too much methanol, I'm not sure about the calculator its not right IMHO,

but 20% methanol for 120L of wvo is 24 litres, so the calculator is giving you 19.2 which is 80% of the 24L for the first stage, leaving 4.8 litres for the second stage.

Although the calculator does say 15.2 for1.9ml dropout in the 3/27 but I don't know why it says that, and if you leave the calculator as 10/90 it says 4.6L for 1.9ml dropout which is a bit nearer but still not the correct 4.8L.

[dgs]

As Chug and I have realised, you have used too much methanol. This won't particularly matter re your process but methanol is by far the most expensive of the two chemicals we use, so it needs keeping to a minimum. Using a lot of glycerol to pre-wash my oil I now use a maximum of 12.5% methanol for total completion.

                     http://www.biopowered.co.uk/wiki/Glycerol_wash

[simonallen]

Thanks for the advice guys. I left the last dropout test on the bench so will see how it's cleared 24 hours later when I get home from work. I have attached the calculator results to show you what it came up with for me, and hopefully you can tell me where ive gone wrong. I guess It will need a lot of washing, and going on the theory of I will get out about as much glyc as the methanol I put in there is still a bit in there, Again I will try and drain some off the bottom when I get home but I've only filled a 20l container with the glyc so far compared to the 30 odd liters of meth I have used.
I now have the glyc to be able to wash the next lot, so will be getting a bit more stable hopefully unless the excessive methanol in this batch of glyc will cause an issue?
I'll give it a go with more catalyst on the next batch. God this is addictive!

Cheers

[Chug]

Most of the excess methanol will end up in the glyc and will be available for the glycwash, some will stay in the bio and will need removing, either by demeth with venturi and then bubble and settle, or by water washing. Yes it is addictive isn't it, keep going you have made a good start and raising the base amount of catalyst will help next time and will get easier as you get more experience.