Explosive New Application For Primasonics Acoustic Cleaners!

When I was a kid and growing up in the small Ulster town of Dromore, we had to look for simple, cheap yet exciting ways to have some fun. I vividly remember one such form of entertainment when recently Primasonics International received an enquiry from a company in India who had a problem storing and discharging calcium carbide.

Back to my youth for a moment and my first contact with calcium carbide which was (indeed, still is for cavers) used as a fuel for carbide lamps. What we did as kids was to buy some rocks of calcium carbide from the local ironmongers, get a tin can which had a press on lid, punch a small hole in the base with a nail to make a cannon. We would then place a small piece of the calcium carbide in the can, spit on it, replace the lid and hold a lighted match over the small hole. The result was BANG - the lid flew off!

This video clip demonstrates my point!

So why does the explosion happen? Well, calcium carbide reacts with water to produce the explosive gas acetylene plus calcium hydroxide known as "slaked lime".

CaC2 + 2 H20 —› C2H2 + Ca(OH)2

However, do not think that calcium carbide is an out of date chemical. China, for example has the capacity to manufacture 17 million tonnes per year, mainly as a raw material for the manufacture of polyvinyl chloride. Calcium carbide itself is manufactured industrially in an electric arc furnace from a mixture of lime and coke at approximately 2000˚C and this method of production has not changed since its invention in 1888.

CaO + 3 C —› CaC2 + CO

The powder when stored in silos can become a little sticky, hence the Indian manufacturer saught our help with silo cleaning - ie. to prevent side wall build up and to aid material flow from the silos.

After studying the silo drawings and calcium carbide physical specification, we recommended the installation of a Primasonics Acoustic Cleaner Model PAS-75 to be mounted on top of each of their silos. We are now also working on an acoustic cleaner solution for the economiser section of their waste heat recovery boiler as well. Our local agent is now arranging to visit with this company to progress the enquiry to a satisfactory conclusion.

How strange indeed that a material I first came across as a boy has come back to me almost 60 years later as a good application for our acoustic cleaners.