Tue | Jul 25, 2017

Clearing the air in St Thomas

Published:Tuesday | January 31, 2017 | 1:00 AM
Beatrice Dunn shows a handful of what she believed to be soot she scooped from the veranda of a home in Duckenfield, St Thomas. According to Howard Chin, the substance is fly ash.

THE EDITOR, Sir:

The material in Beatrice Dunn's hands, in the photograph published in The Sunday Gleaner along with the story 'Sugar, soot and sickness', is NOT soot. It is what is known as fly ash, specifically partially burnt bits of bagasse.

This tells me that, just like at Bernard Lodge when I was there doing some work years ago, the boiler exhaust air speed in the smoke stack was high enough to carry the lightweight bits of partially burnt bagasse up the stack and fall to the earth downwind on Ms Dunn's verandah. The solution is to (a) drop the boiler exhaust air speed sufficiently low for long enough to allow the fly ash to settle out, or (b) increase the weight of the fly ash by spraying something that will stick to it in order to settle out (a lot of water could do the job; some would boil off because of the heat), or (c) run the exhaust gas through a cyclone extractor, which, essentially, spins out the bits of fly ash.

I believe these to be solutions to the problem, only limited by the space available which, to put the equipment.

HOWARD CHIN

Member, Jamaica Institution of Engineers

hmc14@cwjamaica.com