[Digestion] Biogas Accident

Thu Mar 3 08:33:39 CST 2011

Stephen's report suggests two explanations - *neither of them connected with
AD*.

The biogas community must make sure that accurate reports are published
ASAP, before false rumours spread and take root.

1. Gas is the obvious scapegoat for any explosion -* but* *was the cause gas
at all?* Many fine powders can explode if suspended in air - which can
easily happen in a poorly-run factory with a dust-laden atmosphere. Starch
has been known as an explosion hazard for decades. I recall a major
explosion many years ago at the Bird's Custard Powder plant in Banbury,
England - and custard powder is 99% corn starch. Almost identical to tapioca
starch!

2. However, if the cause was gas, a gas explosion at the point of use is
just that - *a simple gas explosion.* It could as easily happen with natural
gas, LPG, hydrogen or any gaseous fuel. The source of the gas would only be
relevant if biogas was more explosive than other commonly used fuel gases -
which it is not. It's safer than many in fact.

*Could someone with good local connections offer to  get the facts - then
nail the rumours! *

In the meantime,* I would suggest we avoid discussing the matter on this
list - *or we'll just feed the rumours. We should also avoid discussing it
anywhere as a "*biogas explosion*". It's just an "*explosion*" unless proven
to be due to gas. And it's just a "*gas explosion"* unless evidence emerges
that the nature of the gas is relevant.

Duncan Martin PhD
Cloughjordan Ecovillage
Ireland
www.thevillage.ie

On 1 March 2011 03:48, Dr Stephen P Etheridge <spe at biotrix.asia> wrote:

>  Fellow AD Listmembers
>
>
>
> I wrote a note on 29th Jan re: Biogas explosions, a subject that could
> potentially affect everyone in this sector. I did not realise that I would
> have to revisit the subject so soon.
>
>
>
> Last Friday at 4.30pm a major biogas explosion at a Tapioca Starch Factory
> in Thailand injured 31, 18 seriously. Since that time 7 have died of burns
> injuries and this number is expected to increase.
>
>
>
> See:
>
> http://www.baanmaha.com/community/blogs/entry470.html**
>
>
> http://www.thaivisa.com/forum/topic/446507-40-workers-injured-in-gas-explosion-in-chaiyaphum/
>
>
> http://www.nationmultimedia.com/home/31-workers-injured-in-gas-explosion-in-Chaiyaphum-30149629.html
>
>
> http://www.ethailand.com/news/five-more-workers-killed-raising-gas-explosion-toll-to-seven-91356.html
>
>
> http://koratfart.com/isaan-news/chaiyaphum-31-workers-injured-in-gas-explosion/
>
>
> http://www.nationmultimedia.com/2011/03/01/national/Factory-death-toll-hits-seven-30149747.html
>
>
>
> Clearly this has the potential to affect everyone in this sector but
> certainly those of us woking in Thailand and S E Asia. As far as I am aware
> this would be the worst biogas accident globally.
>
>
>
> The biogas plant was built by P&S Designs Co., Ltd. -
> http://www.psbiogas.com/eng/intro.html , however the explosion was not at
> the digester, but at the starch bagging plant where the biogas is used.
>
>
>
> The english language press indicates that burning wild grass entered a
> biogas pipe, which seems strange since biogas pipes are sealed. The Thai
> language press indicates that “hot work” (i.e. welding) was taking place
> over a biogas pipe. It is common in Thailand to use HDPE pipe for biogas but
> usually only up to the building where the “point of use” is. After that it
> should be, and usually is, stainless steel. However, if welding was taking
> place near an HDPE biogas pipe then this could have resulted in inital
> ignition.
>
>
>
> There have been two prior small explosions here with faulty burner gas
> valves but this can happen with any gas boiler coupled with poor maintenance
> (Previous explosions detailed in Appendix 2
> http://www.eeec.eng.ku.ac.th/files/Handbook-BiogasSafety-IndustryFactory.pdf
> ). From personal experience in the Thai Tapioca sector the bagging area
> rarely gets the respect it deserves as a potentially explosive area (
> http://www.youtube.com/user/Jermani099#p/a/u/2/s02zYPE_AgM ). Having said
> that, there are more than 200 large scale Tapioca biogas plants in Thailand
> and a biogas explosion has not happened before.
>
>
>
> I suspect that biogas may have ignited and that this may have triggered a
> starch explosion in the enclosed bagging area, but without substantial
> information this is pure speculation at this point.
>
>
>
> I will let the group know if there are substantive developments and I am
> sure we would all wish to express our sympathies to those involved.
>
>
>
>
>
> Stephen Etheridge
>
> spe at biotrix.asia
>
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> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
>
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