[Stoves] Metals in biofuels

[frank]

Tom,

In the GEK we burned walnut shells and no problem with slagging yet the 
report mentions nuts and shells to be a problem due to the high 
potassium. I have not tested the potassium concentration in the shells 
so perhaps it has low potassium concentrations or the temperatures are 
not high enough or we did not burn enough to have a problem.  Can we get 
a slag problem in something as small as the GEK?
 
<snip>

>>I am thinking (hoping) that only the elements that dissolve in a hot acid
>>    
>>
>digest along with sulfate, chloride and phosphate is important for us and
>not the 'rock' material left behind in the acid treatment when predicting
>problems.
>
>The hot acid digest is similar to the chemical fractionation (leaching in
>water, dilute acid and strong acid) that we did in order to identify
>components that volatilize during combustion (water an dilute acid soluble),
>reactor during combustion (Strong acid soluble) and pass through interest
>(residue from strong acid). We found that it is most useful to analyze for
>the total quantity of components, such as total chlorine, rather than just
>the soluble components because we found that in different fuels the
>components had different degrees of solubility. this reflects the many forms
>(usually hydroxides) they take in the plant itself.  
>
>  
>
I found this procedure most interesting. Do you think the components of 
this procedure (1) water sol; 2) dil. acid sol. and 3) strong acid 
sol.4) non-acid sol.) correlated well when looking at slagging and 
make-up? Would you do this breakdown again in another study? Its a lot 
more work and I am just wondering if it was worth while.

Thanks
Frank





>>Thanks - great report!  My head a centimeter bigger.
>>    
>>
>
>That's an asset, not generally a problem. 
>
>I hope this helps.
>
>Tom
>
>
> 
> 
>
>
>
>
>
>
>Tom Miles wrote:
>
>  
>
>>Frank,
>>
>>For evaluating potential problems for slagging and fouling in gasifiers and
>>combustors (e.g. stoves) we use ten elements in the ash reported as oxides:
>>
>>Silica (SiO2)
>>Aluminum    (Al)
>>Iron    (Fe)
>>Titanium (TiO2)
>>Phosphorous (P2O5)
>>Calcium (CaO)
>>Magnesium (MgO)
>>Sulfur (SO3)
>>Sodium (Na2O)
>>Potassium (K2O)
>>
>>Plus
>>Chloride (Cl)
>>Carbon Dioxide (CO2) is measured to estimate losses on fusion. 
>>
>>We measure total chloride in the fuel and of source sulfur. These elements
>>volatilize during combustion and can cause fusion and deposits. 
>>
>>You can see how we use these analyses in the report, "Alkali Deposits in
>>Biomass Boiler", TRM Miles 1995 lined from my website www.trmiles.com or
>>directly at http://www.trmiles.com/alkali/alkali.htm
>>
>>Many thanks for your help with the Gasifier Experimenters Kit (GEK) at
>>    
>>
>ETHOS
>  
>
>>this weekend. It was a big distraction for Charlie to set it up but I think
>>it was worthwhile. 
>>
>>Kind regards,
>>
>>Tom
>> 
>> 
>>
>>
>>-----Original Message-----
>>From: stoves-bounces at listserv.repp.org
>>[mailto:stoves-bounces at listserv.repp.org] On Behalf Of frank
>>Sent: Tuesday, January 27, 2009 4:35 PM
>>To: Discussion of biomass cooking stoves
>>Subject: [Stoves] Metals in biofuels
>>
>>
>>Dear Stovers, charcoal makers and brick makers,
>>
>>Of the list of elements below I am wanting to know the ones that would 
>>be of interest in regards to causing problems, volatile toxins and of 
>>nutrient interest.
>>I have already added As, Cd, Pb, Zn, to my list for possible toxins.
>>I have added Ca, Mg, K, P for possible nutrients in left over char and ash
>>I have added Na, and K that may be problems in making an ash that  forms 
>>blocks (?).
>>
>>Any comments of problems or concern or interest of the following will 
>>help me to put together a test program for testing biofuels.
>>
>>Thanks (again)
>>
>>Frank
>>
>>Aluminum    (Al)
>>Boron    (B)
>>Cobalt    (Co)
>>Chromium    (Cr)
>>Copper    (Cu)
>>Iron    (Fe)
>>Manganese    (Mn)
>>Molybdenum    (Mo)
>>Nickel    (Ni)
>>Selenium    (Se)
>>Chloride (Cl)
>>Nitrate (NO3)
>>Phosphate (PO4)
>>Sulfate (SO4)
>>
>>
>>Frank Shields
>>Soil Control Lab
>>42 Hangar way
>>Watsonville, CA  95076
>>(831) 724-5422 tel
>>(831) 724-3188 fax
>>frank at compostlab.com
>>www.compostlab.com
>>
>>
>>
>>_______________________________________________
>>Stoves mailing list
>>Stoves at listserv.repp.org
>>http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org
>>http://stoves.bioenergylists.org
>>http://info.bioenergylists.org
>>
>>
>>
>>
>> 
>>
>>    
>>
>
>  
>

-- 
Frank Shields
Soil Control Lab
42 Hangar way
Watsonville, CA  95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com