The Pop & Swing Of Economiser Cleaning Success

Most successful outcomes in industry are the result of the ‘appliance of science’. The success story I’d like to share with you today is a great example of that, except that it has one more ingredient - the ability to pop and swing!

One of my earliest blog posts recalled a trip to London to visit London Waste, a rather special power generation plant which converts household waste to energy. They were struggling with material build-up in one of the boiler economisers. Steam soot blowers, water sprays, manual cleaning and grit blasting had hitherto been their adopted methods of economiser cleaning but were not proving effective enough. Also it was not cost effective with periodic downtime of up to 3 days and a cost implication of circa £70,000. So the plant manager was eager to try our acoustic cleaners. Naturally, he needed to discuss the idea in detail to be sure that it was the right choice, hence my trip.

However, the success story that resulted might never have happened had I declined the invitation to take a closer look at the economiser section itself. The plant manager was lithe and fit whereas I …. well, let’s just say I was in a different class, so several leaps of faith were required.

His instructions of “Just pop through that hatch up there” and “Just swing your legs round here” still echo in my mind with a sense of fear and trepidation – and that’s five years on!

The reward for my endeavours? The following year saw 1 x PAS 60 curved acoustic cleaner and 2 of our PAS 75 units installed at the plant.

Two years further on and the plant was so pleased with the improved efficiency of the struggling economiser that a further 4 x curved PAS60 and 8 x PAS 75 were purchased and installed to help the remaining 4 boiler economisers.

PAS75 acoustic cleaner installed on economiser

Another two years later (early 2013), I was invited to return to the plant to look at the problems caused by fine ash in their filter bank (blocking of the filter bags). Following my recommendations, a series of our acoustic cleaners was installed in all these units. (Another story in itself, details of which will come later!)

I am most grateful to London Waste for entrusting their business to my company and also for granting permission to publish a detailed case study which is now available on our website. You can read and download the pdf by visiting our case studies page.

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.