[Stoves] [Stove NOX // ACRYLAMIDE

Tue Mar 5 20:35:15 CST 2019

Having recently been invited to explain NOx formation and getting rid of it after it formed, I had a chance to discuss this with Prof Annegarn when in China.

The N comes from the fuel and most N in fuel becomes NO even if there is not enough O in the fuel to create it. In the case of biomass there is plenty.

After NO is created, it can be converted to N2 and O2 which frees the O to move on to join H or C.

If it is kept above about 820 C for 250 milliseconds it will go that way, or can. Low NOx burners are of two types: those that convert NO to N2 and those that prevent the formation of NO2 at a much higher temperature. It is actually not very helpful to discuss all NOx as if it was similar and certainly not helpful if you are trying to minimize production of it.

You can use a low-N fuel.
You can use a chamber hot enough to convert NO to N2.
You can keep the uppermost temperature below 1250 C.

NO forms easily in a gasifier or fire because the N and O are already joined together in the cellulose with several combinations easily formed. N is often joined to three oxygen atoms with a valence of 4. One of them is joined by a double bond so taking off the two with single bonds, you have NO with a double bond.   N2O a has a valence of 1 for the N and it can be dealt with. NO2 has a valence of 4 for the N and it is "unhappy" because it likes 3 or 5 but the oxygen is satisfied by its complete shell (octet).

It is 2 with NO so keeping it hot and providing a second NO gives N2 and O2 which happens if given time and temperature.

N2 has a triple bond and is very stable.

As for fuels, the amount of chlorophyll can be used as a vague indicator of the N content so leaves have far more and wood far less than average for a whole plant.

Therefore we expect pellets made with leafy material (corn stover) to have much more NO in the exhaust compared with wood pellets. If the combustor is properly constructed, it can be greatly reduced.

I only have detailed tests for coal fires in which the conditions are good for NO reduction. The effect is pronounced: exhaust that would otherwise have an emission factor of 600 ppm (undiluted sample) can be reduced to the low 200's with combustion chamber design alone. Let's call it a 60% reduction.

It is quite important to remember that a stove fuel combination has inherent emissions, and accidental emissions, and some like NO which are from an inherent elemental component but which like Sulphur, can be emitted in less or more polluting forms. Poor combustion of S gives H2S when it should be SO2. N should be N2 not some other molecule.

Just because NO (and CO) forms easily doesn't mean we have to "accept it".we can play a few tricks.

Regards
Crispin

From: winter.julien at gmail.com
Sent: March 5, 2019 6:54 PM
To: peetersfrans at telenet.be; stoves at lists.bioenergylists.org
Cc: franke at cruzio.com; Crispinpigott at outlook.com; boll.bn at t-online.de
Subject: Re: FW: [Stove NOX // ACRYLAMIDE

Hi All;

I have not looked into it in detail, and certainly not in the last three years.  However, in the back of my mind, NOx can form in freeboard flame area of moving grate gasifiers when there are higher amounts of excess (above stoichiometric requirements) air.   I expect that this would be a larger problem with fuels that are high in nitrogen.  This could arise for biomass stoves that burn compressed fuels that have higher amounts of leafy material or dung.

Cheers,
Julien.

On Tue, Mar 5, 2019 at 6:02 PM Peeters Frans <peetersfrans at telenet.be<mailto:peetersfrans at telenet.be>> wrote:

Verzonden vanuit Mail<https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgo.microsoft.com%2Ffwlink%2F%3FLinkId%3D550986&data=02%7C01%7C%7C98b45d53b7704477ad7808d6a1c5f1f2%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636874268864042358&sdata=qVtbs3EOJAfpctVyZzpoz%2F1Q0i9pSN7Mdi0j3lRhh2w%3D&reserved=0> voor Windows 10

Van: Julien Winter<mailto:winter.julien at gmail.com>
Verzonden: dinsdag 5 maart 2019 18:18
Aan: Discussion of biomass cooking stoves<mailto:stoves at lists.bioenergylists.org>
Onderwerp: [Stoves] Unexpected Rising Levels of Atmospheric Methane

Hi all;

This week's podcast from the BBC's "Science in Action" talks about unexpected increases in methane, that may be coming from expanding wetlands in the tropics.  https://www.bbc.co.uk/programmes/p002vsnb<https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.bbc.co.uk%2Fprogrammes%2Fp002vsnb&data=02%7C01%7C%7C98b45d53b7704477ad7808d6a1c5f1f2%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636874268864052369&sdata=CqFhhxsxuJnOm3P5icD9InYTjzzU0H5Wj2LdwrUn%2BQY%3D&reserved=0>   "Rising Methane Levels Impact Climate Change"

We need to have methane included as a standard measure of cookstove emissions.

We should also be looking at the interaction between stoves and different types of fuels on the emissions of NOx

Cheers,
Julien

--
Julien Winter
Cobourg, ON, CANADA

Hi Julien,

   Long time ago you dreamed to have a FRENSCH FRITTES sales place in Canada ….But to cold for patatos breeding !
But with the CLIMAT CHANGE…..There is hope .

     NOX ?   I think you only get it under motor pressure from new DIESELS. Not the old with lower pressure .

But for the FOOD heated over 170° C , the sugar and proteins are making CANCEROGEN ACRYLAMIDE !!!
So watch the COOK with FRENSCH STUPID BEHAVEOUR making food BRONZAGE or CRME BRULER ……….
Such cook belong in prison .
Safest is steam cooking .

    Succes Julien .

Regards

Frans

--
Julien Winter
Cobourg, ON, CANADA
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