Anyone doing the glycerol remix?

[StorminNorman]

I have read previously about the remix of prior batch glycerol that seemed to lower the gel point of processed bio. Girlmark's blog makes passing reference to it, but no real explanation, that I found.

It seems reasonable that there are some unutilized chemicals in the waste that could be used to pretreat the oil and lower titration by knocking some of the FFA out. I am going to try it and wondered if anyone had some pointers as far as temps and mixing times. I use KOH as a caustic, so there is no issue with gettting it mixed back in.

My plan of attack, unless diverted would be to heat to 130-140, mix for a half hour or so and let it settle out. Titrate and process. I will titrate before the remix just to see if there is an appreciable drop in value.

Thoughts on the process or first hand experiences appreciated.

Norman

[girlmark]

Hello Norman,

I think you're confusing two different techniques a little bit.

I was writing about the glycerol remix prewash, which is done in order to cut down on the soap that you have to wash out.

Once you're finished mixing your biodiesel in the reactor, you add 5% water to the reactor, mix again for couple of minutes to get it evenly dispersed, then let the glycerine settle normally. You will then have slightly cloudy biodiesel which has a lot less soap in it than if you hadn't added the water. The reason this works is that it makes the glycerine by-product scavenge more of the soap. This is because a more 'watery' glycerine by-product is more attractive to soap than the 'oily' biodiesel is.

You have to wash the fuel afterwards, the slightly cloudy appearance is a sign that some water gets into the biodiesel, so you don't want to use it without washing if you do this method.

I think the technique you're thinking about however is a different one. There was some technique where people discovered that adding glycerine to waste vegetable oil before making biodiesel somehow made heavy fats fall out of it, which then improves the cold-weather performance of oil and the biodiesel that is made from it. Basically, it makes fats settle out more completely. Most waste oil is made from both oil and fat, and the more solid fats make poorer-performing cold-weather fuel.

I think that the thread that you're looking for is this one: http://biodiesel.infopop.cc/groupee/...9441081511/p/1

[StorminNorman]

Thanks Mark.

You are correct, of course. [img]/ubbthreads/images/graemlins/laugh.gif[/img] I remember the thread now that I read it again. I currently do the water wash in the processor and will just keep on disposing of the glyc as needed unless I run across some really fatty oils that is otherwise good.

Need to process a bunch of oil this week as I have a 1200 mile trip scheduled next weekend and I want to make it all on bio.

[scottefontay]

And, especially if you do the water wash, adding glycerin to your oil before processing will add water and could make headaches. There is a small amount of water in the glycerin anyway.

[RickHredf250]

Hey Norman, how you going to haul that much Biodiesel?
Rick H...

[StorminNorman]

SI sells a new 110 gallon translucent tote out of their cash and carry store here for $135 plus tax. I got one for my finished fuel storage. It is about 4 feet tall and 3 feet diameter with a flat bottom. No bottom drains to leak. I set it on a pallet so I can move it around the shop with a pallet jack, or in and out of the truck with the forklift. I originally got it to do the WVO pickup with, but picked up a 275 gallon tote with steel frame for that.

Norman

[girlmark]

whoa- that's a great size tote for anyone who's upscaling- the 275's are really big for some people. Could you give us a link or a photo?

Mark

[StorminNorman]

The totes are 48 inches tall and 36 inches diameter, 110 gallon capacity. The odd configuration is to mount a pump in the valley to protect it from damage acording to one salesman. Another tells me it is so you can tap it and use vacumn or air to move product in or out since there is no bottom tap. A bulkhead fitting to put a 2 inch outlet in the bottom is $10 additional. Last time I was out there they had about 20 left. I never did ask if it is a regular production tank or not. Anybody that needs one I would be glad to help if I can, although shipping charges would be a killer.

http://photos.thedieselstop.com/show...hp?photo=29080
http://photos.thedieselstop.com/show...hp?photo=29081

Norman

[Spencnaz]

I have been mixing in about 5 gallons of glycerin by-product (I use the KOH method so it's liquid) back into my 160 gallon aluminum WVO storage tank to lower cloud point of the biodiesel plus hopefully to recover some methanol from the previous process.

Also, I've obviously noticed that the titrations are much lower. The one problem I have been having is adequate WVO filtration with my pump station from the tank. I'm going to have to engineer something that will fit on the output of the generic Harbor Freight rotary barrel pump. I have been using a section of nylon stocking (panty hose), but it will clog in short order. All biodiesel produced from my reactor is filtered through a whole-house water filter system to eliminate any particulates (I think larger than 5 microns, but I'm not sure).

[CS Shaun]

I've been pre-treating my wvo w/ glyceryn and have found that the gell point is lowered 20 to 25 degrees. Not sure if titration is better because my oil supply varies somewhat but I really like the way the finished product performs in cold weather. I run 75% bio in 1 tank and 50% bio in the other tank and I haven't had any problems w/ plugging filters or no-starts.

I"m sure I wont continue this process once it warms up a bit more but it's great for winter time.

Shaun

[girlmark]

the gel point of the biodiesel or the gel point of the WVO itself?

Mark

[StorminNorman]

Mark and others more experienced--Your thoughts, please, on Scotts comments above concerning using the glyc with prewash water as a glycerol prewash to lower gel point. It is cold here in Nebraska tonight, but I do not believe we will be running less than B100 for very long. I will not be concerned with gel point until October or so.

If the WVO is heated to processing temp, 130 degrees, when the previous batch glyc is mixed in and circulated for 15 minutes and settled overnight, do you think there would be enough water transfer to interfer with the normal titration and processing of the oil for biodiesel? I would think that the water would move back to the glyc and settle out. Of course somewhat controlled experiments are probably needed.

Norman

[ak_cowboy]

You know, I have had mixed results with the mixing the glycerin with the oil. Sometimes it seperate, sometimes it makes gravy. Any ideas why that is. I am using the 5% prewash now but that is all. I have found that regardless of how long I let the reacted bio settle, I still have to filter it. I don't was my fuel, I just prewash settle for a week or so and run. I noticed getting a little glycerin in my filter so that is why I filter before that fuel tank now. I know alot of people are going to bust my chops for not washing but I don't have the resources to do it. No running water near garage and no drains either. I am in the Coast Guard and live in housing and I am just lucky to get to make bio here. So the prewash is better than nothing

[CS Shaun]

I was talking about the gel point of the bio-diesel. Before I was seeing cloud point arond 42f and now it's ranging between 20 & 25f.

[girlmark]

I dont' have an opinoon on it because I haven't tried it. However, various people have- check the link to the infopop forum on 'winterising biodiesel' that I listed above and see what their experiences and theories have been.

If it corrects gel point by that much, that's really significant!