[Stoves] on gasifying palm kernel shells

M. Nurhuda mnurhuda at ub.ac.id
Sat Aug 24 00:28:19 CDT 2013


Dear Paul,

Palm Kernel shells are very good fuel. They contain a lot of fixed C. Even
they are burnt in a stove of  natural gas, the flame is very clean and hot
with flame  mixing of blue and pinkish color.

Please check the video:

https://www.youtube.com/watch?v=g7TZn6YGOcI

Have a nice week end.

Kind regards
M. Nurhuda




> Yesterday I received some palm kernel shells from Malaysia, and proceeded
> to run them through my 150 TLUD of only a 25 cm height.
>
> The gasification of the palm kernel shells looked like this:
> http://www.youtube.com/watch?v=IDFHPjLx08A&feature=youtu.be
> I am not so happy with this result: too much of an orange flame.
> But I am not sure of the moisture content of these shells, and I doubt
> that
> they were in the ideal 10 to 12% range.
>
> When I mixed in some rice hulls with the palm kernel shells, the flame
> looked like this:
> http://www.youtube.com/watch?v=N_sI4zKUuq8&feature=youtu.be
> This represents a remarkable improvement in flame color.
>
> I am trying to understand why rice hulls have they effect that they have,
> either when processed alone or in conjunction with some other material.
> There is the initial combustion reaction that provides a lot of heat to
> the
> process. This reaction gives rise to a lot of CO2. But the water gas
> reaction, the water shift reaction and the methane reaction do not convert
> this CO2 into CO. It appears that there is only one reaction that can do
> this: the Boudouard reaction where C + CO2 gives CO.
>
> Let us suppose that if the biomass is at 10% moisture content and if the
> AER is at 0.3, the temperature at the combustion reaction reaches 800 C or
> more. According to what I have been able to understand from Tom Miles, it
> is at this temperature that the Boudouard kicks in. But if the gas expands
> quickly and cools off after the combustion reaction, the Boudouard
> reaction
> will not take place. So we end up with a dirty gas full of CO2.
>
> But if rice hull char situated above the gasification front provides a lot
> of resistance to the flow of gas and does not allow the gas to expand and
> quickly cool off, then it could be possible for the Boudouard reaction to
> take place, even in a small TLUD. When CO burns, it does so with a blue
> flame, and if enough CO is present in the gas, the flame color is a rich
> blue.
>
> If there are relatively large spaces into between the palm kernel shell
> char above the combustion zone, the gas quickly expands and cools off: no
> Boudouard reaction and a lot of dirty gas is produced.
>
> Does this make sense?
>
> Thanks.
> Paul Olivier
>
>
> --
> Paul A. Olivier PhD
> 26/5 Phu Dong Thien Vuong
> Dalat
> Vietnam
>
> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
> Mobile: 090-694-1573 (in Vietnam)
> Skype address: Xpolivier
> http://www.esrla.com/
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