Cement Plant Pre-Heater Fan Acoustic Cleaning With Sonic Horns

Silo cleaning (preventing side wall material build-up and eliminating bridging) is something we have written about extensively before. A good example is a sonic horns blog post from last year entitled Giving New Meaning To Silo Cleaning as well as this key page on our main sonic horns website about Cement Bulk Storage Bin Cleaning & Silo Cleaning.

Silos, however, are not the only part of a cement plant where material build-up can be a problem and we find ourselves servicing an increasing number of enquiries for the cleaning of other plant elements such as pre-heater ID fans.

Particulate build-up on the blades can cause a pre-heater fan to go out of balance and if this happens during production, the whole upstream plant has to be closed down, the fan manually cleaned and then the whole plant gradually restarted. Such unscheduled downtime is very expensive. Typically, the build-up is an extremely hard, brick-like substance which can break off during operation and cause serious imbalance and possibly damage to the fan casing.

This video shows our 120Hz sonic horn in operation on a pre-heater ID fan at a cement plant in Malaysia. You can actually see the particles being debonded as the sonic horn sounds. Sonic technology at its effective best!

Sonic Horns: The Solution For Baghouse Cleaning

Power generation plants form a vital part of any country's infrastructure so their efficiency is of paramount importance. Downtime can be very costly with many negative, knock-on effects.

Our sonic horns can help improve efficiency and avoid downtime in power plants and we were particularly pleased with how we recently helped a US power company solve their baghouse cleaning problems.

Scenario: The plant has a large baghouse with six compartments. The baghouse is located behind a scrubber so particles are very fine. The product is coke and coal ash combination. The plant had been experiencing severe material build up on the filter bags which was not being removed by the conventional filter cleaning system of blowing high pressure down the bags about every 15 seconds.  So they approached us to see if we could help with our sonic horns.

Now we know from experience that such a build up causes a big increase in differential pressure across the filter bags which then behave like a blocked vacuum cleaner and lose power. Also the life of the filter bags (which are not cheap in terms of purchasing replacements plus the time to strip out and refit) is greatly reduced. Moreover, if the filter subsequently fails then the whole upstream plant has to be shut down. So this baghouse problem was really hurting them with regard to running both of their boilers.

Solution: We suggested the installation of our sonic horns and as they needed help fast but with no prior experience of acoustic cleaning, they wanted to tread carefully and so opted for a rental plan. They rented 4 of our 75Hz horns in early August this year.

However, within 10 days they informed us there was a problem - the horns only worked when the filter with its vacuum was switched off. We spent the next month getting them to check various things as we had not supplied the ancillary items - they had sourced these themselves. Each part was checked and found to be OK. So by mid September they were convinced that our horns would not work under vacuum and were considering returning them to us. However, we knew for certain that our units do work well under vacuum as baghouse filter plants are a popular area for our sales.

The only solution was for our Technical Director to visit site deep in Alexandria Louisiana. On October 12 he flew out and worked on site with the engineers during the night when the plant was not operating. He tested everything and then found that they had installed the mountings for the horns the wrong way round. The moment these were changed the units worked perfectly and the engineers on site were amazed at the amount of particulate they debonded.

The company has since confirmed its intention to purchase these four sonic horns and to purchase a further 8 units for installation during their next shutdown.

Question: So why 75Hz as opposed to any other?

 Answer: Our in-house computer modelling software (designed in conjunction with the University of Liverpool) indicated that this was the most appropriate model for the application in question. Two filters separated into 4 sections with one 75Hz horn per section.

Proof that the sonic horn is the ideal solution for baghouse cleaning. 

Improving Thermal Efficiency With Sonic Horns: Boiler Economizer Cleaning

Economizing on energy consumption is vital for all types of industry but surprisingly this is no new concept.

It was more than 150 years ago in fact that the very first successful design of economizer was used - in steam engines. Patented by Edward Green in 1845, it increased the steam-raising efficiency of the boilers.

Today the need to reduce energy consumption is an even greater priority and applies to most industries around the world. For them, improving thermal efficiency and generating as much heat as possible from burnt fuel is key. This is where maintenance and correct functioning of economizers comes in. Keeping economizers clean is crucial. That may sound simple but it is not!

Many economizers have a complex tube configuration (plain tubes and finned tubes) which means that although traditional soot blowers might be installed to do basic cleaning, there can be problems leading to the shutdown of the boiler for manual cleaning. This is where sonic horns (aka sonic soot blowers) come into their own.

The following testimonial from one of our clients who operates a large waste-to-energy plant speaks for itself:

"We have had an internal problem with our Economizer mid bank steam soot blowers for some time. The tube configuration in that bank is such that it has plain tubes at the top and finned tubes at the bottom of the same bank. Historically, we would have had to shut the boiler down to go into the economizer pretty soon after the development of such a fault in order to repair the steam stoot blower and manually clean the tube bank because of the rate of fouling being so high. However, currently draught loss has remained insignificant thanks to the operation of the sonic horns. I would happily endorse your product to any interested party in the future".

This photograph shows 3 of our sonic horns fitted to the economizer of the waste to energy plant referred to in the above testimonial. Read more about our sonic horns for boiler economizer cleaning.

Sing Sing Sing & The Clarinet/Sonic Horn Analogy

The one or two of you who regularly read my sonic horns blog who will know that I am a Big Band (swing and jazz) fan. I have just recently been to see the UK top big band, Chris Dean’s Sid Lawrence Orchestra at a lovely theatre set in the middle of the English Lake District – The Theatre by the Lake, Keswick, Cumbria.

The band played one of my favourite numbers "Sing Sing Sing", first made famous by the ‘King of Swing’ Benny Goodman. This number has a strong drum beat in it and Benny’s drummer was the fantastic Gene Krupa. You can watch a video of his band playing this great jazz swing number.

Benny Goodman’s trade mark was his clarinet which is an instrument made up from an end bell section, a main stem section and a top mouthpiece which contains the reed.

Most clarinets are either Bъ or A. The base note is produced by blowing air through the reed which is then amplified to a particular high or low note by a combination of the stem and the position of the open holes on the stem. If the base note produced by the reed can ‘escape’ out of the first hole, then a high note (high frequency – short wavelength) is produced. If the lowest positioned note on the stem is open then the base sound wave has to resonate up and down the stem causing it to form a longer wavelength and therefore a low note is produced.

This is exactly the same principle used by us in the design and construction of our range of sonic horns. The ‘reed’ is a titanium disc housed within the Wave Generator and when compressed air is introduced it vibrates rapidly causing a base note. Then by altering the size of the bell section we can produce a number of fixed key frequencies ranging from 420 Hz (high frequency) to 60 Hz (low frequency). Take a look at our sonic horn website if you would like a more detailed explanation. I have written a section dedicated to understanding sonic horns.

Our acoustic cleaners cannot play "Sing Sing Sing", but they are extremely effective at preventing particulate build up and providing material flow solutions in a wide range of both plant and industry applications.

Giving New Meaning To Silo Cleaning

One of the primary industries where sonic horns bring particular advantage is that of the cement industry. In a large cement factory there can be many process and storage problems and sonic horns can really help by:

1. preventing particulate build-up (in id fans and electrostatic precipitators)
2. by improving material flow (eg. in cement silos and hoppers)

See our cement silo cleaning page for more information.

Photograph: our most powerful sonic horn (PAS-60) installed on a 30,000 ton capacity cement silo.

Today, however, I came across a 'first' ... a cement factory with no less than 30 cement silos where our sonic horns could not be installed! The reason? It has been converted into an architect's office!

Architect Ricardo Bofill discovered the 3,1000 m2 cement factory in Barcelona back in 1973 and spent 2 years redeveloping it into his head office/home. Surrounded by beautiful gardens it has to be one of the most unusual office/homes I've ever seen.

Read more on this story and view the pictures

Artistic Sonic Horns

I'm generally not given to wandering around art galleries (any free time I have is absorbed by a passion for cooking and big band jazz!) but I was passing Tullie House Museum & Art Gallery in Carlisle recently when a poster for an unusual art exhibition caught my eye. Entitled "Underwater" it looked a little unusual and rather interesting. So I ventured in.

The premise of the exhibition was clear .... artistic efforts by a range of contemporary artists to capture the essence of life beneath the oceans and remind us of our origins.

The art forms were certainly not of any standard type but varied and fascinating - from videos to drawings and photographs and there was even a motorized model submarine struggling to escape the clutches of a giant squid!

I walked around the quiet gallery, intrigued by all that I saw and then, as I wandered to the very back of the exhibition, I began to hear noises. I gravitated towards where the sound was coming from. As I stood at the entrance to this particular room, I was stopped in my tracks by what I saw ........... it was a series of sonic horn shaped, metallic horns suspended from the ceiling, eminating underwater recordings of fish and other sea creatures.


I walked around the room and in between the horns. It was a unique experience both visually and aurally. All credit to the artist Klaus Osterwald for his creativity.

Proof that art and engineering can combine to inspire!

Sounding The Sonic Horn For Disaster Relief

Supplying sonic horns brings me into contact with a wide range of industries and the highly skilled, engineers and technicians associated with them.

These industries include:

Cement & Gypsum

Pharmaceutical

Petrochemical

Power Generation

Within the latter industry, I have been privileged over the years to encounter some of the finest engineers in the world – from fossil fuel power plants to nuclear power plants. In the nuclear power sector. nuclear waste encasement is an important issue and, through an extended involvement in cement production for that purpose, their engineers have become very familiar with sonic horns – used today as the preferred option for maintaining optimum silo performance.

Why mention this now? Well, nuclear power has always been a much debated topic and this week of course the debate has been heightened by the tragedy of the Japanese earthquake and tsunami. It is a tragedy on a scale that defies belief but one where we can all help, if only just a little. Charities such as the Red Cross, Unicef and Save The Children are all working in support of the disaster relief effort. For more information on how to make a donation and for the latest updates on the Japanese crisis here is the Google Crisis Response page