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wood chip life span?
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Iam switching to wood chips and iam not setup to demeth, my question is does anyone know how long wood chips last if you dont demeth compared to if you do demeth?

Thanks!!
 
Location: md | Registered: January 30, 2010Reply With QuoteReport This Post
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Holy Cow! No one responded your easy question?! Sorry about that! But hopefully you found some previous answers by searching the forum.

So basically it depends on your bio and how much of the glycerin and methanol you've removed prior to filtering. The longer/more you settle and aerate the bio to remove glycerin, soap, methanol the longer the wood chips will last/work.

Based on reading the forum there really isn't any set point as this can depend on the type of wood your using. But the basic rule of thumb is to test your bio frequently with the water shake up test. Also I've noticed once my bio starts coming out cloudy it's time to use fresh wood chips, which should have been replaced earlier.

Jerry
 
Location: Indianapolis | Registered: November 18, 2004Reply With QuoteReport This Post
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If you are not going to demeth at all then I would recommend sticking with water washing.

On the other hand; if your chips are hard wood and properly prepared they can do the job for quite some time.

RolfQuo (see interview linked in my sig) has 2 sets of 4 drums each of wood chips and they have seen 1/2 million liters between them. Last year they added a drum of Purolite PD206 resin after the chips on each set of drums, and although these are still the same drums of chips they are still seeing ZERO ppm soaps.

My own set up mimics this and I have been using the chip drum for over a year now in front of the resin tanks and my results are also ZERO ppm soaps.

The chips will not, on their own, remove methanol, that is not their purpose. They work on soaps primarily and this is most efficient when the methanol is no longer present as it acts as a binding agent for the soaps which is what keeps them in suspension in the biodiesel. Once the methanol removed then the soap s become free of suspension and can either drop out on their own with sufficient settling time or pushed to do so by using chips and resin.

The longer you settle the biodiesel after demething it the more soaps will fall out of suspension and then the longer the life of your chips will be.

HTH



** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


 
Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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Ours typically sees between 60 and 70 thousand litres through 75kgs of sawdust before they need to be changed. Soaps typically go in <2000ppm and come out ~500ppm.

edited: Corrected sawdust mass

This message has been edited. Last edited by: BWilder,
 
Registered: February 25, 2010Reply With QuoteReport This Post
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If you skip demeth lifespan is shortened. I use a three barrel system to avoid demething. The first barrel takes a hammering, second cleans most of whats left, third barrel polishes it clean and shiny.

Purolite etc is not needed at all anymore and is mostly used by people who already had the setup before wood tech matured.

Lifespan is dependent on methanol and soap saturation of the wood.

Allowing meth to evaporate or washing it and soap out of the wood with water will extend/renew life of media.

Demething obviously removes both methanol and soap before bio reaches the wood so greatly extends lifespan.

The wood works by demething the bio then acting as a depth filter for the precipitated soaps.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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ant what are you testing your fuel with, what are the results? i'm in the process of installing my wood chip towers and was wanting to avoid demthing, purolite, etc. my towers are 6"x70". what is your settling time prior to washing, whats your process in general?
 
Location: southern IL | Registered: October 11, 2008Reply With QuoteReport This Post



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I settle for at least an hour, overnight if the titration is five or less. Higher I worry about byproduct setting as I use sodium hydroxide catalyst. It varies depending on what else I am doing when I process. When you ask about testing I assume you mean for soap content. I have used various methods but have settled on a very simple one to tell me if the fuel will effect my fuel filter; the only reason I care about soap content. I take a small sample of fuel (>50ml) and nuke it in the microwave to remove the methanol. This precipitates any soap and tends to coagulate it on the surface when it bubbles during heating. If soap is a problem you will see a layer or film of some kind. To be sure I then spin the sample in a centrifuge. This concentrates any precipitants in the narrow pointy bit at the bottom of the centrifuge tube. If there are none at all then your bio is soap free. I developed the method myself and call it the nuke and spin. I like it because it is quick and easy to do. It lets me see the soap directly with my eyes instead of indirectly through the results of a chemical test. More intuitively obvious what is going on.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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