[Stoves] Three fuel combustion/pyrolysis papers

Sat May 20 12:29:24 CDT 2017

Dear Mr Larson

Thanks for sharing the research papers. What is unclear to me is the
distinction of the flaming and the smoldering phase.
*How do we know in an practical experiment that the flaming phase is over
and is the beginning of the smoldering phase.*

Mitchell et al., 2016 (The first and second paper shared by you in the
trailing mail), in their study found that flaming phase emissions were much
higher than in the smoldering phase. CO emissions are also dependent on the
combustion phase. *So is emission measurement the a criteria to evaluate
the distinction of a phase?*

Quoting a paragraph directly from the paper
*Batch combustion in a fixed bed follows three major stages. Ignition
occurs first once the surface material of the fuel devolatilises and forms
a gaseous flame. Once this flame is established the ‘flaming phase’ takes
place characterised by the combustion of volatile products and their
decomposition products (secondary pyrolysis products) as luminous diffusion
flames. Thirdly the smouldering phase occurs which is characterised by
heterogeneous char combustion and limited visible gas phase combustion.
Elasser et al. [17] have recently identified four combustion phases but in
the present work we have used the simpler classification of the two major
phases, flaming and smouldering because of the difficulty of distinguishing
between the other phases.*

Gravimeteric measurements of particulate matter samples at an interval of 5
minute was done during a cooking cycle. Each of the filter paper would then
be analyzed for EC-OC . The EC/TC ratio is an indication of the different
combustion phases (Mitchell et al., 2016).

Atiku et al., 2016 (by th same group from Leeds University) in their study
found that the values of the EC/TC ratios for wood logs, torrefied
briquettes, coal and smokeless fuel are highly dependent on burning
conditions; namely the flaming and smoldering phases. The results of this
study suggest that EC and OC emissions from various solid fuels differ
substantially in composition and relative proportion.

Smoke emissions from the different fuels are also dependent on the phase of
combustion. Roden and Bond, 2006 identified that cooking fires exhibited
three general combustion phases, which were named as vigorous flaming,
gentle flaming, and smoldering.

a)      Vigorous flaming is characterized by strong flames with a jutting
appearance, resulting from rapid de-volatilization from the wood. It occurs
shortly after the ignition of added wood.
b)      Gentle flaming is characterized by smaller flames, lower emission
of scattering and absorbing particles, and a gradual decrease in CO2.
c)      Smoldering, occurs when the flames have extinguished.

Roden and Bond, 2006 studied the influence of flaming events and found that
very dark particles with the optical properties of black particles are
emitted during this phase. During the vigorous flaming phase, the emissions
of particles are very high, especially dark, light absorbing particles
associated with low instantaneous single scatter albedos. CO2 usually peaks
toward the end of vigorous flaming. In the gentle flaming phase scattering
and absorption coefficients were often similar in magnitude during this
phase, indicating that both strongly absorbing and non-absorbing particles
were emitted. Carbon monoxide concentration followed either the scattering
or absorption coefficient. In the smoldering phase, light scattering
increases sharply because flames are not consuming the volatile matter
emitted from the wood, which recondenses into particles. Despite the lack
of flame to create black carbon, these aerosols still have an absorbing
component. CO emissions here are no greater than those of the preceding
gentle flaming phase. The decreasing carbon dioxide concentration shows a
drop in burning rate.

*So during realtime emission measurement of stove, can we say that to
determine **which combustion phase we are in, there can be two parameters
to define that*
*A) EC/OC ratio *

*B) CO/CO2 ratio*
Regards
Darpan

On Sat, May 20, 2017 at 10:26 PM, Ronal W. Larson <rongretlarson at comcast.net
> wrote:

> List:
>
> 1.  This one appeared as a Journal-recommended non-fee paper:
> “The impact of fuel properties on the emissions from the combustion of
> biomass and other solid fuels in a fixed bed domestic stove"
>
>    - E.J.S. Mitchell
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>a
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0005>
>    ,
>    - A.R. Lea-Langton
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>a
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0005>
>    ,
>    - J.M. Jones
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>a
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0005>
>    ,
>    - A. Williams
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>a
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0005>
>    ,
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#cr0005>
>    ,
>    - P. Layden
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>b
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0010>
>    ,
>    - R. Johnson
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#>b
>    <http://www.sciencedirect.com/science/article/pii/S0378382015301843#af0010>
>
>
> http://www.sciencedirect.com/science/article/pii/S0378382015301843
>
> It fits TLUDs in the sense that a TLUD separates the two distinct types of
> burning (flaming and smoldering) - and (hopefully if one places the char in
> soil) one never sees the second type.  I have NOT read this carefully, but
> looks well done.
>
> 2.   From a totally different source this one appeared with a similar
> flavor:
> The impact of fuel properties on the emissions from the combustion of
> biomass and other solid fuels in a fixed bed domestic stove
> <https://recommendations.springernature.com/v1255/redirect/004bM9w-ENjUDU5H2pVUL17iSbuwMKVCjjjyi2fmgQy_Pkthsyu_4YHhRbwzsJyH4DdRhtmVrAZLjXdxRWFEfQDZ7apxqf-z_xWLbCeQuOE1XKrSe4w5mShj2OXoLQ6X7ZwyDcbGMDkqA5b23U7MvijGIg6JNq8JxfpopB31uvluETRcg-zUK-uSL5TVVe6_eK-AJAcEbytnI5U_KvJ_IG0KrRfZtESgYqNVVPDAz_9AqAZOxx2qEqXqf_lbxxUCjMaqVGYM8tvfd7HUF4SLLKstjY4CGAG7Tnk7ZcnKR9BmNOWKU8_Laikhewva_0iHJpmS0kJoDE3QitwRJ6O7n1x_qsXHop5oDgDuAXpJQwLLdOjGjv-pC6ZZK4FKf4S0qjpsjnEZn5K9QTF1lMBn_P2H-jUCU1OUxF7PRz96_lFKcHlFBUY4rfJn5EnzX7xvZ2-xzhvlhsIZsNvmC-tJugJLsNaZGLlCohTN-ZBKD16Iv1-JD6PTnXU5aFn8yy-uJuliffCQqwHhP8ml1yV0MXEQoXuou5KuDqpLDYSc3gjXlakHnI-FAMf5K5yoIpI4Tx1ruKQaeR9y-rl0yfmqWRZNWpmTkKQSouI7R_xoOEiWXXyCGuAGzpxE79AsM5rCsNgjklwL98wFV8wAwcycioMAGU9taiN2GtGR9NYnoJv8b4DV1COrk_MN_hKypxYdUQUCXquUghBqxSchWYeYjcce0Q_UzmGdt-ePYETRmsK5lKuGIveNwoiWxebl00q7AarHZtW11aNFVJz02_7-k0_jr4hKhmop3xGUbUpyMekQFeNo-N4210_qmDLmVpCIPvFscyk2t2bNBea7tw6EQBApaoKo21_OwS9MSM1DwQIdQIP-tLlt_4evPMis-HNYrrTe362LYrnFe_Y3iNKeUreMsP8QMB_1qbe-q8RLklBo9Qv1Sr6joVo4uVUc4Wr3ALUX6CAa5QMUMRkXUikRPUAlaNdn43GpGdL7CnQfSfqK3iY3fv-1DRyFKjIM8qtrbHljmYnJ0vTqD1XAWJu781LSSdZni3l0YzVKFva3g3hnmnV1ZUCkZ04Yq_vfAV2T>
>
>    - Mitchell, E.J.S.
>    - Johnson, R.
>
>
> <https://recommendations.springernature.com/v1255/redirect/004bM9w-ENjUDU5H2pVUL17iSbuwMKVCjjjyi2fmgQy_Pkthsyu_4YHhRbwzsJyH4DdRhtmVrAZLjXdxRWFEfQDZ7apxqf-z_xWLbCeQuOE1XKrSe4w5mShj2OXoLQ6X7ZwyDcbGMDkqA5b23U7MvijGIg6JNq8JxfpopB31uvluETRcg-zUK-uSL5TVVe6_eK-AJAcEbytnI5U_KvJ_IG0KrRfZtESgYqNVVPDAz_9AqAZOxx2qEqXqf_lbxxUCjMaqVGYM8tvfd7HUF4SLLKstjY4CGAG7Tnk7ZcnKR9BmNOWKU8_Laikhewva_0iHJpmS0kJoDE3QitwRJ6O7n1x_qsXHop5oDgDuAXpJQwLLdOjGjv-pC6ZZK4FKf4S0qjpsjnEZn5K9QTF1lMBn_P2H-jUCU1OUxF7PRz96_lFKcHlFBUY4rfJn5EnzX7xvZ2-xzhvlhsIZsNvmC-tJugJLsNaZGLlCohTN-ZBKD16Iv1-JD6PTnXU5aFn8yy-uJuliffCQqwHhP8ml1yV0MXEQoXuou5KuDqpLDYSc3gjXlakHnI-FAMf5K5yoIpI4Tx1ruKQaeR9y-rl0yfmqWRZNWpmTkKQSouI7R_xoOEiWXXyCGuAGzpxE79AsM5rCsNgjklwL98wFV8wAwcycioMAGU9taiN2GtGR9NYnoJv8b4DV1COrk_MN_hKypxYdUQUCXquUghBqxSchWYeYjcce0Q_UzmGdt-ePYETRmsK5lKuGIveNwoiWxebl00q7AarHZtW11aNFVJz02_7-k0_jr4hKhmop3xGUbUpyMekQFeNo-N4210_qmDLmVpCIPvFscyk2t2bNBea7tw6EQBApaoKo21_OwS9MSM1DwQIdQIP-tLlt_4evPMis-HNYrrTe362LYrnFe_Y3iNKeUreMsP8QMB_1qbe-q8RLklBo9Qv1Sr6joVo4uVUc4Wr3ALUX6CAa5QMUMRkXUikRPUAlaNdn43GpGdL7CnQfSfqK3iY3fv-1DRyFKjIM8qtrbHljmYnJ0vTqD1XAWJu781LSSdZni3l0YzVKFva3g3hnmnV1ZUCkZ04Yq_vfAV2T>
> Fuel Processing Technology 2016
>
> <https://recommendations.springernature.com/v1255/redirect/004bM9w-ENjUDU5H2pVUL17iSbuwMKVCjjjyi2fmgQy_Pkthsyu_4YHhRbwzsJyH4DdRhtmVrAZLjXdxRWFEfQDZ7apxqf-z_xWLbCeQuOE1XKrSe4w5mShj2OXoLQ6X7ZwyDcbGMDkqA5b23U7MvijGIg6JNq8JxfpopB31uvluETRcg-zUK-uSL5TVVe6_eK-AJAcEbytnI5U_KvJ_IG0KrRfZtESgYqNVVPDAz_9AqAZOxx2qEqXqf_lbxxUCjMaqVGYM8tvfd7HUF4SLLKstjY4CGAG7Tnk7ZcnKR9BmNOWKU8_Laikhewva_0iHJpmS0kJoDE3QitwRJ6O7n1x_qsXHop5oDgDuAXpJQwLLdOjGjv-pC6ZZK4FKf4S0qjpsjnEZn5K9QTF1lMBn_P2H-jUCU1OUxF7PRz96_lFKcHlFBUY4rfJn5EnzX7xvZ2-xzhvlhsIZsNvmC-tJugJLsNaZGLlCohTN-ZBKD16Iv1-JD6PTnXU5aFn8yy-uJuliffCQqwHhP8ml1yV0MXEQoXuou5KuDqpLDYSc3gjXlakHnI-FAMf5K5yoIpI4Tx1ruKQaeR9y-rl0yfmqWRZNWpmTkKQSouI7R_xoOEiWXXyCGuAGzpxE79AsM5rCsNgjklwL98wFV8wAwcycioMAGU9taiN2GtGR9NYnoJv8b4DV1COrk_MN_hKypxYdUQUCXquUghBqxSchWYeYjcce0Q_UzmGdt-ePYETRmsK5lKuGIveNwoiWxebl00q7AarHZtW11aNFVJz02_7-k0_jr4hKhmop3xGUbUpyMekQFeNo-N4210_qmDLmVpCIPvFscyk2t2bNBea7tw6EQBApaoKo21_OwS9MSM1DwQIdQIP-tLlt_4evPMis-HNYrrTe362LYrnFe_Y3iNKeUreMsP8QMB_1qbe-q8RLklBo9Qv1Sr6joVo4uVUc4Wr3ALUX6CAa5QMUMRkXUikRPUAlaNdn43GpGdL7CnQfSfqK3iY3fv-1DRyFKjIM8qtrbHljmYnJ0vTqD1XAWJu781LSSdZni3l0YzVKFva3g3hnmnV1ZUCkZ04Yq_vfAV2T>
>
>  (only free at this single site)
> http://eprints.whiterose.ac.uk/85463/1/A%20study%20of%
> 20soot%20formation%20from%20biomass%20combustion.pdf
> (again - I haven’t read carefully - but has the same breakout into two
> types of combustion (Flaming and smoldering)
>
>
> 3.  And this one was also recommended at the same place.  We have
> discussed Dr. Tryner’s thesis work before, but I’m not sure this particular
> article.   I like it very much:
>
> The effects of fuel type and stove design on emissions and efficiency of
> natural-draft semi-gasifier biomass cookstoves
>
>    - Tryner, Jessica…
>    - Marchese, Anthony J.
>
> Energy for Sustainable Development 2014
>
> <https://recommendations.springernature.com/v1255/redirect/004bM9w-ENjUDU5H2pVULzvM3jlkn27KyMViPvscv-hi-CXyEoj-tptLg8NkrJ1ARoTdXKWTMElsXB1g-CiQnPzRdUXhoi-9SXKcJZRxYxIoGbZ3R9Q0GFRfs7kUT4TRf3hobROqIJ1mZFrTAXhPSBWWkDBVbduwXW-wC_BiP7iSLZZSBFkdrLfVRHTwKNYDmzp-qlZTEDMdCoBiBL2IlG47Z_bx8JNhY3Lmp25m0ReBiRO4vNBeaSgGGC4n1gX5IeaoIjiZtMwD6E9ATUliZFop4OK3VtiHKklUJpakxsawLW_DRz63VFwfpJo7zPsFTatV3lOgsbpA6Hd1QA9S05l-DsPcEuDpcJKwW0yb8pJj64wpr4GLpkmQYP-CDT9ed42HyqXRTfL7eBQhuPet1r-Y2p1qeWgAMLkkAsriGDlt3aHy2EN34JhCH5cRePyXU5zNcFsX7eF0JEFaZ_pRCzjuyseIco7qB8btUpm3N1jk7c3Cxs6JP8HDYSot73vQDYLoMzdEJG33n4Al1QUQS0tRPMEuhcHEeK7CJHF7LvpKRKIHbXX07AyUqP157ogTOvKZ6cyF-HhVayouHRBsbO3hAsWaG4eurQVGl_DDyV5G0ibhYREeLdjSaj2-z75GwgE-4gMNO4NULwQaGsmi1SAuEvCIpIX6VaCMrtVR84edvETSkP4ZP9PPFAp47IKN8FxiYYe4LQaX_87KGz8aVv1-WRtHqBZN3H-gWW9r94efROJ6rVhhHbxW_GnP6zFs6E9jefYGFOPNZeMBLnKITgQ7YZPx4UW7VMWhQpTWSjt5J3lwHS-AE0dlvpU8beaTa5xqywUi4g1j9_Hgbrd0p6mjYNelB_AGTGVKSg0SoZ0yGzqWNplm1-YqWypfYER0PmyD8lHJMAPG--kJooqkK_YA5FC5AeL0pStS9QCqriJN_zlx0hlfP4NWrQpLPDCV9CK0V6aQOHkYk5dgfZwb5l8LPoeJYMivvfzOWnEW4PStBXnZFMuRNswl_4dxAjUXpTASiKfTgzZjSGtJKsI8KiY4gRTBjEStOoopPWbBEf8%3D>
>
> <https://recommendations.springernature.com/v1255/redirect/004bM9w-ENjUDU5H2pVULzvM3jlkn27KyMViPvscv-hi-CXyEoj-tptLg8NkrJ1ARoTdXKWTMElsXB1g-CiQnPzRdUXhoi-9SXKcJZRxYxIoGbZ3R9Q0GFRfs7kUT4TRf3hobROqIJ1mZFrTAXhPSBWWkDBVbduwXW-wC_BiP7iSLZZSBFkdrLfVRHTwKNYDmzp-qlZTEDMdCoBiBL2IlG47Z_bx8JNhY3Lmp25m0ReBiRO4vNBeaSgGGC4n1gX5IeaoIjiZtMwD6E9ATUliZFop4OK3VtiHKklUJpakxsawLW_DRz63VFwfpJo7zPsFTatV3lOgsbpA6Hd1QA9S05l-DsPcEuDpcJKwW0yb8pJj64wpr4GLpkmQYP-CDT9ed42HyqXRTfL7eBQhuPet1r-Y2p1qeWgAMLkkAsriGDlt3aHy2EN34JhCH5cRePyXU5zNcFsX7eF0JEFaZ_pRCzjuyseIco7qB8btUpm3N1jk7c3Cxs6JP8HDYSot73vQDYLoMzdEJG33n4Al1QUQS0tRPMEuhcHEeK7CJHF7LvpKRKIHbXX07AyUqP157ogTOvKZ6cyF-HhVayouHRBsbO3hAsWaG4eurQVGl_DDyV5G0ibhYREeLdjSaj2-z75GwgE-4gMNO4NULwQaGsmi1SAuEvCIpIX6VaCMrtVR84edvETSkP4ZP9PPFAp47IKN8FxiYYe4LQaX_87KGz8aVv1-WRtHqBZN3H-gWW9r94efROJ6rVhhHbxW_GnP6zFs6E9jefYGFOPNZeMBLnKITgQ7YZPx4UW7VMWhQpTWSjt5J3lwHS-AE0dlvpU8beaTa5xqywUi4g1j9_Hgbrd0p6mjYNelB_AGTGVKSg0SoZ0yGzqWNplm1-YqWypfYER0PmyD8lHJMAPG--kJooqkK_YA5FC5AeL0pStS9QCqriJN_zlx0hlfP4NWrQpLPDCV9CK0V6aQOHkYk5dgfZwb5l8LPoeJYMivvfzOWnEW4PStBXnZFMuRNswl_4dxAjUXpTASiKfTgzZjSGtJKsI8KiY4gRTBjEStOoopPWbBEf8%3D>
> http://envirofit.org/wp-content/uploads/2016/06/2015-
> The-effect-of-fuel-type-etc_Tryner.pdf
>
> A phrase in the abstract surprised me - that 60% of the energy can remain
> in the char.  I have never seen the remaining char this high - which should
> improve the economics if/when one is able to sell the char.
>
> Ron
>
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-- 
Darpan Das
Research Scholar
IIT Bombay
India
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