Brian Hughes

@digger... Thanks for the reply- I'm leaning towards a spark plug in the can, a teaspoonful of petrol or a squirt of gas from a blowlamp, and stand well back.

 

 

I would steer well clear of thunder flashes etc as they are not net gas producers and can create large overpressures at short range.

3 new concepts- I was sort of under the impression that a bang is a bang- a fast release of gases. Are there any quick pointers to where I can get up to speed with the technicalities and distinctions of squibs, maroons, and thunderflashes?

Any idea what they use in vehicle airbags?

Thanks to all who took the trouble to reply, but I think the replies are drifting away from my original question: Can I use a pyrotechnic device to simulate an explosion within the gasifier to prove, for my own peace of mind, and for sceptical safety inspectors, that an explosion has somewhere safe to dissipate?

@Cooperman435 Thanks for the reply- gasification covers two distinct processes, firstly, heating coal or biomass to pyrolyse and release tar vapours, and secondly, passing hot CO2 and water vapour through a bed of charcoal to form a reduction zone- get the temperature gradient right, and the gases reduce to carbon monoxide and hydrogen. The carbon monoxide is a great fuel gas in every way. Except one. It's poisonous and kills people, and producing it under positive pressure just isn't an option.

Vapour/air explosions do occur in the comparatively small volume of an engine inlet manifold, and there are sometimes provisions for this- in my case, there's a worst case scenario of 20 litres of explosive mixture, which I need to simulate to show that the explosion has somewhere harmless to go.

Thanks for the replies. What happened- an educated guess- was that there *was* an air leak into the gasifier- 20 litres at slightly below atmospheric pressure- and the mixture ignited. The only path for the explosion was back through the air inlet, sending burning charcoal into the air. I'm aiming to mitigate the consequences as well as the likelihood of an explosion by giving it somewhere safe to go- a sprung lid, or something similar to a vehicle air bag- hopefully, making sure that any explosion is a "whumf", not a "KABOOOOOOOOOOOOM". I like the idea of a spark ignition source to ensure that an explosion happens sooner rather than later. My game plan for for checking out squibs was to have a method of testing and demonstrating explosion containment with the system cold. 

How are commercial squibs specified? Do the manufacturers quote a figure for the explosive energy in joules?

@Arthur Brown- there were several gasifier designs that kept countries moving when petroleum was scarce- the Imbert downdraft system seems to be the common theme, and a lot of interest today. Check out:

https://northernselfreliance.com/

and:

http://thedrizzlerga...blogspot.co.uk/