[Stoves] stoves and credits again
Frank Shields
franke at cruzio.com
Fri Sep 22 11:11:09 CDT 2017
Stovers,
I believe this H/C ratio should be used as the char being sequestered. But the equipment is expensive (~#30+k) and the hydrogen can be tricky to get a good value. Used in a ratio and a small difference can make a big difference in results. And a very small sample is used of about 0.2g.
I’m thinking a TGA as a possible replacement for what we are doing. The left over char is placed in cups of several grams and easy to run, say, four reps. They are dried at 150 c. (per Hugh suggestion), then nitrogen flushed in the system and heated to 500c and determine any change in weight, then oxygen flushed into the system and the ash determined. all on the same samples. I have never used a TGA but they are common and many second hand ones available. Leco makes a good one I am told.
The char left can be 1) used or 2) not used for sequestered carbon. There is no percentage that can be used IMO. It is made properly or it will biodegrade. So the loss in weight from Dried >> to >> 550c in nitrogen should be close to nothing to be called Char and used. Not yet sure what ‘Close’ means, perhaps a change less than about 5%. Then you calculate out the ash determined at the end.
Because char high in cations 9grasses, leaves etc) when charred in oxygen will convert some of the carbon into carbonates (inorganic carbon) I am thinking we can ignore inorganic carbon as long as the ash is less than 20%. Chars with greater than 20% ash should not be considered as biochar due to problems in testing and that no natural clean woody material will have ash greater than 20%. And IMO biochar should be from clean natural materials - or called something different the biochar. (co-gen char, manure-chars etc.).
Bottom line: The char left passing the test from weight loss from (150c to 500c) can be used as sequestered carbon. The weight loss from 500c in nitrogen to 550c in oxygen is mostly carbon to be used for sequestered carbon. If the test from 150c to 500c does not pass (to much weight loss) then just add it to the soil with no carbon credit. If the ash is above 20% then call it some char with a qualifier attached as to what its made from.
Frank
> On Sep 22, 2017, at 8:25 AM, tmiles at trmiles.com wrote:
>
> Since the 2008-2009 work IBI developed a protocol for determining how much carbon could be considered sequestered. This protocol was adopted and amended in 2016 by the California Air Pollution Control Officials (CAPCOA). It has not been adopted by an international body.
>
> The protocol is based on the ratio of hydrogen to organic carbon in the char. The maximum is 0.7. Many gasifier chars are well below that. The class the ratio puts you in determines how much carbon you can claim for sequestration. Someone has probably looked at this for TLUD’s but I don’t have that information handy.
>
> Tom
>
> From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Paul Anderson
> Sent: Friday, September 22, 2017 6:16 AM
> To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org>
> Subject: Re: [Stoves] stoves and credits again
>
> Crispin,
>
> Thank you for the message and for calling attention to the spreadsheet dated July 2008. I am sure that it is useful. To someone. This is not in my realm of activities.
>
> What I (we) can hope for is that someone will use your message and spreadsheet and then help me understand its significance to the topic.
>
> Paul
>
>
> Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
> Email: psanders at ilstu.edu <mailto:psanders at ilstu.edu>
> Skype: paultlud Phone: +1-309-452-7072
> Website: www.drtlud.com <http://www.drtlud.com/>
> On 9/22/2017 7:36 AM, Crispin Pemberton-Pigott wrote:
>> Dear Paul
>>
>> The energy in a fuel can be estimated well using the following formula
>>
>> HHV (in kJ/g) = 0.3491C + 1.41 H - 0.1034 O + 0.1005 S - 0.0151 N - 0.0211 A
>>
>> Where C is the (mass) fraction of carbon, H of hydrogen, O of oxygen, S of sulfur, N of nitrogen, A of ash
>>
>> There are other formulas in use - this one I believe comes from Tom Reed.
>>
>> The conversion from HHV to LHV is standard and well known, accounting for water vapour generated by burning the hydrogen.
>> The compensation for moisture content is also well known involving a subtraction for the mass of water and then for heating and evaporating that moisture.
>>
>> So using the above formula only you can get a pretty good estimate of the energy content of a wood or char fuel.
>>
>> I developed a spreadsheet for determining the energy released during various portions of a Water Boiling Test to see how the assumption that the moisture left the fuel 'constantly' compared with the assumption that the fuel dried first and burned later. It is attached, and it uses the above formula.
>>
>> You can enter fuels of your choice and burn and water loss choices to see how the energy released by the fire is accounted.
>>
>> To use it, put in the dry fuel analysis, for example the Douglas Fir is entered in row 13. The moisture is entered in cell E12. That will calculate the wet basis ultimate analysis in row 12.
>>
>> Do the same for the char remaining at the end in rows 15 and 16.
>>
>> Rows 18-24 are the calculations provided by the WBT, at that time the UCB WBT 3.1 (uncorrected, maybe?).
>> Rows 28-32 are the calculations proposed where the fuel evolves during the burn. The point was to compare the energy released values on the right. The heat released calculation error is posted on the far right, in all cases the WBT over-estimates the energy released during a section of the test.
>>
>> In the upper section the LHV is given for both the dry and moist fuels on a per kg basis.
>>
>> You can enter any fuel, liquid or solid, just use the dry ultimate analysis as the raw data then enter the fuel moisture to get the current value. For ethanol and kerosene there might be no moisture at all.
>>
>> Regards
>> Crispin
>>
>>
>> -----Original Message-----
>> From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org <mailto:stoves-bounces at lists.bioenergylists.org>] On Behalf Of Andrew Heggie
>> Sent: 21-Sep-17 14:54
>> To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org> <mailto:stoves at lists.bioenergylists.org>
>> Subject: Re: [Stoves] stoves and credits again
>>
>> On 21 September 2017 at 18:17, Paul Anderson <psanders at ilstu.edu> <mailto:psanders at ilstu.edu> wrote:
>>>
>>> 1. Pyrolysis is around the 550 to 650 C range (unless burning very
>>> hot with much forced air) 2. The char yield is about 20% of the dry
>>> weight of the biomass fuel (mainly think of wood).
>>> 3. That char contains about 30% (NOT 50%) of the ENERGY of the biomass.
>>
>> Paul I have had a look at some of the early work on charcoal, I see graph by Pohl 1970 that show charcoal heated to 600C being composed 90% fixed carbon, now if you ignore the other 10% that contains carbon hydrogen oxygen and ash and you still have 20% of the original dry weight then you have 18% of the original dry weight as carbon. So if you start with dry hardwood at the 18.6MJ/kg Tom Reed allowed for it and most woody biomass and end up with 0.18 carbon at 33MJ/kg so about 32% in the fixed carbon plus a contribution from the 8% of tars etc.
>> less the 2-3% ash (more ash from leaves buds straw etc.) So I suspect you are more right to be at the lower end than the 50% I gave which is what I remember from charcoal made at lower temperatures for sale in barbecues.
>>
>>
>>>
>>> If writers wish to continue to say 50% of the ENERGY remains in TLUD-type
>>> charcoal, then let's resolve that here and now. Otherwise there can be no
>>> true discussion about the value of the TLUD char.
>>
>> Agreed, let's see what figures others have.
>>
>> Andrew
>>
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Thanks
Frank
Frank Shields
Gabilan Laboratory
Keith Day Company, Inc.
1091 Madison Lane
Salinas, CA 93907
(831) 246-0417 cell
(831) 771-0126 office
franke at cruzio.com
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