Brief history. Two years ago I started making biodiesel, standard appleseed, HF pump, separate wash and dry tanks. NaOH 5g base, 20% methanol, about an hour of processing at around 130-135. I had to be very gentle washing, nearly always had some layer of 'cottage cheese' emulsion. The last two batches I made back then I tried the then 'new' 3/27 test and had drop out.

After a year break, I've changed some things that have helped immensely. I've moved to KOH 7g base but the most important changes I made are dewatering, increasing reaction time, and 5% prewash. I now heat my oil to about 160 and pull a vacuum on it, this oil passed the splatter test but I still see water boiling out under vacuum. Most importantly I now run about a 4 hour reaction time, depending on the quality of the oil (I've had batches range from 2.7 to 4.8 KOH) it will pass the 3/27 test between 2.5 and 3.5 hrs mixing. I also run the temp a bit hotter at 135-140 with about 5-10psi of pressure to raise the methanol boiling point because I live at a higher altitude. Finally, the 5% prewash seems to do wonders for making washing pain free. I have a standard stand pipe bubble wash setup, and after 3 to 4 vigourous wash cycles the water is clear, and no emulsions at all. Additionally, the biodiesel clears at a MUCH lower temp in the drying tank than it ever did before. I pass the 3/27 test and shake'em up test every batch.

I bring this up to show that just by tweaking your process, you can get dramatically different results. I didn't buy any new equipment, just changed the way I use it. Learn from my mistakes, thank goodness I did.

My question is, what would you folks recommend to speed up the washing process? Bubble washing works just fine (and appeals to my frugality), but it is a bit tedious and time consuming, start the bubbler before I leave for work, drain tank when I come back, start again before I go to bed, and repeat. I would love to shorten that time, and try and keep with my theme of modifying the process and not buying new widgets.

Sounds like we are doing the same exact process. I also wash as you do and it takes 2-3 days of washing. A couple of things I've noticed may be contributing to the # of washes it takes.

1) When I take a sample of the mixture before settling. I let the sample settle then do the 27/3 test. If it passes I turn off the pump and start settling. NOW getting to what I observe. After about 18-24 hours, my sample jar has good separation, but the BD on top is a bit cloudy. So I expect the appleseed contents to look the same, and drain and transfer it to the wash drum and continue with the process....over the next few days, I notice that the BD in my sample jar is getting clearer every day and within a few days, is crystal clear. I can read newsprint thru it. I say this because I'm thinking on my next batch I'm going to process as I regularly do, but I'm not going to drain and transfer it for about a week. What I'm thinking is the the more glyc. that drops out the less washing will be needed. Since I don't need to make batches every week, this delay will not hurt me, but in the long run, I may spend less of my time processing 35 gallons.

2) I think I wash more than I need to. When I transfer to the wash tank, I immediately take a reference sample and put in a dishsoap bottle and begin doing small batch washes with it to indicate when the large batch should be done. I've noticed that the large batch takes a few more washes before I get clear water. I've determined that the drum is not fully draining like a cone bottom tank would, and the wash water gets contaminated with left over soap, and that is why my wash water is not getting clear. So on future batches, I will take reference samples after every wash and do small batch washes to determine when it is finished and not depend on the drum wash water...that is until I can afford a cone bottom tank.

Sorry for the long post, regards, IROKCJ5

You and I have experienced a similar learning curve. I am now putting out better bio with a better focus on the process, not on the processor.

I do not bubble wash. I used to but I hated the process. The ONLY time I got an emulsion was on a bubble wash cycle. I do a couple of static stir washes and about three aggressive spray washes with a garden hose. I use lots of water, but hey, water is not expensive, right?

I am installing a water source and a water heater in the building I make bio in. (I now run a garden hose from another building) I think I am going to go to continuous warm mist washing using Graham Laming's plans for never overflowing tank.

Turn it on, come back 4hrs later and you are washed.

I can think of a few things you might want to try crispyjones.

Heat makes the wash go easier. You will have to get creative to add heat to the wash cycle without adding wigits. One person used an extra long garden hose in the sun to warm up the water. Adding heat will give you the greatest gain.

If you have a choice between hard and soft water, pick the hard water.

You might try varying the timing on the bubbler. I've considered short bursts of like 10-20 min followed by an hour or two of settling repeated throughout the day. That lets you bubble more aggressively with less chance of mayo. I've never tried it, but the theory is good.

On the final bubble wash, let it bubble a really long time, like 12-16 hours. It makes drying a breeze.

If you up the methanol to 22%, you should be able to cut the process time back down to under two hours.

Check out glycerin pretreatment info here. You add your glycerin to your raw wvo and let it settle out. It helps to reduce the ffa and cleans out some of the trash while it's at it. also helps dry the wvo.

Finally, Check out http://www.make-biodiesel.org for some alternative recipes.

Big Mike,

This is the simplest way to get a continuous mist wash:



The PVC pipe adjusts for liquid height in the tank.

try adding an over night static wash before bubble washing..

if you need to have to faster..

like rick said..heat...
I can short my process to a day but it takes more hands on time. otherwise it normally take me 2-4 washes and 1-2 days to wash and dry.

if you want to spend the time..use the pump on your drying tank to circulate with water, but watch the layer at the bottom..when the 'BD lay start to get near the bottom turn off the pump and let it settle. then repeat.

-dkenny

Thanks for the replies, here is my normal wash cycle (usually takes 4). My wash tank holds about 10 gallons of water, I fill up two cubbies with hot water from the bath tub, the wash tank is plastic and seems to hold the heat pretty well. I have a generic fish tank bubbler with two outlets, one is a pill bottle filled with rocks and lots of holes, the other is a circle of tubing with holes in it (supported by some bare copper wire). My first wash is the only gentle wash, I only use one outlet of the bubbler with the air cut off a bit, bubble for 4 hours. Every wash after that I run for 8 hours of full strength bubbling. I seem to be able to really flog the stuff without a hint of emulsion. The last batch actually cleared in the wash tank, when I pumped it into the dry tank I actually got emulsion because the water layer was too close to my BD in the wash tank, oops.

@irokcj5 good point about not draining all the contaminated water. I know I trap at least a couple quarts of soapy water, that would probably add a bit of contamination to each wash cycle. Though I do rinse the thing out between batches.

@RickDaTech looking at the GL plans that BigMike referenced let me see if I can sort out your set up. The clear line going to the top of the PVC vent must be from the bottom drain. You say the PVC is adjustable, is that accomplished by sliding it in the conduit clamps? I assume you must use some type of misting sprinkler head, do you just hook your garden hose to it, is it cold water? How long (and what does that mean in terms of gallons) does it take for you to get to clear drain water? I am not very clear on how this system sets the lower water level with reference to the stand pipe.

crispyjones,

The two hole pipe straps have a spacer between them and the 2x4 that lets me tighten down the straps and still lets the pipe slide freely. A hose clamp above one of the two hole straps sets the height. Not shown in the photo is the vent pipe is actually 2 feet tall to let me adjust it down by two feet.

The clear pvc is attached to the low drain.

I'm using a low flow misting system. Makes a fine mist, but stingy on the water.

The standpipe does not play into this system (except for fine tuning the process)

I find I use less water if I cycle the water on and off. If I just run one long mist wash it uses about 60 gallons for a 30 gallon batch. If I cycle it on and off frequently, I can get down to 15 gallons for a 30 gallon batch.

I capture the wash water in a drum. I'll add some epsom salt to clear it up, then suck the biodiesel off the top with my turkey baster.

The spent wash water makes the grass grow.

Thanks
RickDaTech

I am studying the set-up, looks easy.

Mike...

Rick's wash system is pretty much like mine except I would reverse the drums. That way you can see the seperation line and drain down to just below the standpipe to get the bd out. It also lets you seen the ever present emulsion line encountered at first stages of wash.

Rick and Raften,

Do you recommend a stir/static wash and drain prior to the continuous wash to cut down on the emulsion layer?

Mike...

If your having ongoing emulsion problems, yes do a static wash first.

I've got to make another wash tank soon and on the new one I'll be using a poly drum. I can't find a good food grade steel drum here in the sticks. Metal drums get snagged for burn barrels as fast as they get emptied.

Go to your local instant oil change place,, and ask if they can save you a barrel. their tranny fluids and rearend lubes, come in steal 55's,, but their oil comes in bulk. A good place to get poly drums aswell. My local place has a car wash built in also, and I have gotten a few 30 gallon polys from there as well. those come with rinse agents and soap in them.

In the early days, we never seemed to get clear water, until we started to drop out the wash water and also the end mayonaise, a few litres, which is kept aside. By dropping off this soap, the next lot of water is not going through the soap layer again and clears with far fewer washes. Meanwhile the mayonaise has settled and you can draw off the biodiesel from the top. works for me. Jim.

How are you pulling a vacuum?

I want to run some tests on something that I heard from a good source. That is that if you are able to get all of the methanol out of the freshly processed biodiesel than the glycerin (which is being held by the meth.) will fall out and take most of the other junk with it and thus reducing your number of washes and amount of wash water.