Hi guys

I'm having a terrible time with my processor and it stems from two (i think) main problems: I cannot seem to get all the water out of the oil and the oil is titrating fairly high (5.5).

First, what is an easy, time efficient way to dry my oil? It won't all settle out and I am filtering my oil to minimize water-holding crud. I heat it to 130 F and settle overnight, but no water settles to the bottom. Boiling the water is not an option in my poly processor (or energy efficient)....am I going to have to put a vacuum on it while heating it in a separate tank?

Next, what is the point at which an oil is better suited for acid/base than single stage? My oil titrates from 4.5 to 5.5 and, from reading on this forum, seems to be in no mans land as far as suitability for either one. Would the single stage work better if I switched to KOH (mixing NaOH into meth takes forever at these high use rates) and my glycerine goes thick on me too.


any ideas would be appreciated.

Travis

I'm new to making biodiesel as well so I can't offer much help. I was just wondering if it would be possible for you to try and find some better oil? 5.5 is really bad!

My oil gets heated to at least 190 and a lot of water settles out in about a week. I regularly make Bio from oil that titrates at 7 or higher.

fabricator- do you use NaOH or KOH on that high titrating stuff? My mini batches on the 5.5 will have a distinct glycerine layer but the top will turn to solid glop also...I tried it with the 3.5 + titration and 20% meth and with the 5 + titration and 22% meth.....same result with both. also the yield is not great. not that it matters because the top is not biodiesel by any means. what gives?

dogg4585,

Switching to KOH will increase yield drastically. I have been getting exquisite oil from a country club and it's been tritrating like 0.75 - 1. However, recently, we got a batch of oil from a rendering plant that titrated at 4.5 - 4.8 depending on where in the batch you took it from.

I ran 4 batches using NaOH and each time, it didn't matter whether I used new methanol or not or whether I had used an acid esterification, I got soap. Bad results, we're talking about 50% yield if I was lucky.

However, I got a sample of KOH from a company and test ran a batch. It failed 3/27 barely. A little bit of fallout due to spilling some of the methoxide, not keeping it up to temperature and subsequently not stirring enough (other job obligations). However, the stuff is great.

KOH dissolves very well in methanol and unlike NaOH, dissolves clear rather than clouding up the mix.

Part of the reason we suggest 5g/L NaOH and 22% methanol is because with 3.5 and 20% you run the risk of starving the reaction.

quote:

Originally posted by dogg4585:
fabricator- do you use NaOH or KOH on that high titrating stuff? My mini batches on the 5.5 will have a distinct glycerine layer but the top will turn to solid glop also...I tried it with the 3.5 + titration and 20% meth and with the 5 + titration and 22% meth.....same result with both. also the yield is not great. not that it matters because the top is not biodiesel by any means. what gives?

I use KOH exclusively, most of my oil is 6 or higher I usually use 8 as the base amount and 22% methanol made up of one third reclaimed and 2 thirds new methanol, I have been getting 94 to 95 percent yeild on 125 gallon batches.

Travis
I run acid base on every batch - my oil is dry but titrates up to 13.5g NaOH. Running the acid stage gets the titration down to 1.5 or so, thereby reducing the NaOH required, and the glycerol produced. 5.5 is probably getting too high to reliably process - 3% FFA (3.9g) has been suggested as the threshold for the base only process. Above this level I have had success with the base only process, but yield is less and there are sometimes problem batches.
Try 0.193ml H2SO4 / g NaOH titrated with 8% methanol for the first stage and see the FFA reduction. Retitrate and react with 14% methanol and NaOH.
Shane

Thanks for the input everybody, and so quickly!

I am ordering some KOH to try a single stage and ordering some sulfuric to try the two stage.

shane-lets see if I have this straight before trying a mini batch....Example titration is 5, so mix .965 ml (5*.193) sulfuric into 8% methanol, introduce to (how hot?)degrees F oil and mix for (how long?) minutes, then what? do you drain byproduct before retitrating and continuing?
Then retitrate and mix methoxide containing 5g + titration NaOH with 14% meth and react for (how long)minutes at (how hot?) degrees F for the last part. Then settle for (how long)hours and drain glycerine. Will the glycerine be liquid?

thanks again

quote:

Originally posted by nzunimogger:
Travis
I run acid base on every batch - my oil is dry but titrates up to 13.5g NaOH. Running the acid stage gets the titration down to 1.5 or so, thereby reducing the NaOH required, and the glycerol produced. 5.5 is probably getting too high to reliably process - 3% FFA (3.9g) has been suggested as the threshold for the base only process. Above this level I have had success with the base only process, but yield is less and there are sometimes problem batches.
Try 0.193ml H2SO4 / g NaOH titrated with 8% methanol for the first stage and see the FFA reduction. Retitrate and react with 14% methanol and NaOH.
Shane

Shane, I too have oil that generally titrates near 11.5 NaOH. You mention dry oil. I have been heating to 190F and settling til the temp is down to 140F. this is usually 8 hours or so. Rarely do I get any water to drain off. This past week, I began with oil that titrated at 11.5, I took it to 200F for 8hours and boiled off the water. When the water stopped flowing, I cut the heat and pump, when it got to 140F, I dosed with 2.2 ml H2SO4 + 12% methanol. The reaction stalled at 8. I again dosed with 1 ml Sulfuric + 6% methanol. The reaction stalled again at 6. Another 1 ml sulfuric + 4% methanol finally got the titration to 3+. Of course the duration of this was some 3 days, before getting to the base stage, which is far too long. You did not mention any water created by the acid stage. How long do you process the acid stage? Do you begin the base stage immediately after the titration? How long to get from 13.5 to 1.5? Based on fabricator's comments on this thread, he mentions settling for a week after taking temp to 190F. Could water be the culprit that is creating problems with the acid stage?
Thanks, jackmac

Hi Travis ;

You can' t seperate water with settle tank if the oil icludes water ( ppm ). You should to dry your oil. firstly filtre WVO then I use vakum pump and dry oil to 150-200 ppm.