I am a seasoned Mechanical Engineer, however, most of my 15 years experience has been on the nuclear side of power generation.  I am leading a very small team to evaluate and improve soot blowing performance on a boiler with PRB coal.  As you might imagin, I am on a steep learing curve to understand soot blowing, performance measurements and practices.  I am also going to a soot blowing symposium by an equipment manufacturer in a couple of weeks.

I am looking for advice on sources of information to help me get up to speed on keeping the boiler tubes clear of ash build-up.

Going to the symposium is probably your best introduction into getting the basics of soot blowing. After that, it really comes down to experience. We have been burning 100% PRB for about 10 years in our boilers, and what I have found out is optimization of soot blowing is learned on the job.

As a side note, our thermal performance engineers have been working with software to determine the cleanliness factor before and after soot blowing to optimize the frequency of blowing.

You are faced with different scenarios regarding the soot blowing requirements of a PRB fired boiler.

First is the furnace, where water as well as steam is often used to get the slag off the furnace walls with the wall blowers.

Next is the SH/RH/generating tubes/economizer tubes, which can use any combination of steam, air, water, and or sonic methods.  I suggest you google "sonic sootblowers" too.  While their place is limited, there is a place for them.

Also investigate explosive methods of slag removal.  Shotguns fired from obvservation ports is commonly done on PRB coals.

Once, about 25 years ago, while in a PRB fired station, taking a lunch break with the mechanics, they got to spinning yarns about the slag removal exploits that they had experienced.  As they described 'dynamiting' one particularly large piece of slag build up, I asked "how big was that piece of slag?" and Bubba answered 'about the size of a school bus.'  To which, another mechanic fired up and said "it wasn't that big, it was only about 8' X 10' X 40'....hmmm...well/Ball Valves, I guess that is just about the size of a school bus, isn't it?"

In another station larger than 750 MW in my corner of the world some years ago, a large piece of slag build up fell and took out the "Vee" bottom of the furnace.  It caused an explosion that remains officially unexplained, but which my personal opinion is that it was a hydrogen explosion caused by the disassociation of water that escaped from the ruptured ash furnace bottom tubes and sprayed onto the red hot ash.

You may be a good one to do this, as you have no preconceived notions, nor axes to grind with respect to what has already been done.

The major soot blower companies that google would find all should have reps in your area.  I suggest setting up appointments with each one and letting them come in and do a walk down of your system with you and make recommendations for improvements.

Remember that each will be wanting to supply you with new equipment, that is how they exist, so take it all with a grain of salt, but, that said, those guys live in that world 24/7 and if their proposals have merit, they can give references for locations where their proposed solution has produced results for you to check out.

Don't forget one thing about the OEM boiler designers.  Basically they wanted that thing to make its performance at initial commercial operation testing, and to survive the one year warranty period.  Past that; it is your baby.

Other than that, unless someone at your utility prepared a cracker jack specification, what you have there is the best equipment 'low bid' can buy.

You have to look at it from that perspective.  This is totally unlike the nuclear side where uh-oh's can get you names like Three Mile Island or Cheyrnoble, and there is a NRC type entity looking over your shoulder for reliability and safety.  No gov't entity cares if you melt your boiler or not, and most state's PUC's rules are written so that you can pass your combustion inefficiencies right through to your rate payers.

There are companies out there whose whole existence comprises of making better mouse traps to improve the performance of all types of OEM equipment, including utility boilers.  Some call them pirates, and some are no more than pirates in that they are copy cats making inferior stuff.  Some, however end up with improvements so significant that the OEMs themselves have to go back and incorporate them into their designs in order to keep the aftermarket people from taking all their business.

Some of the links I gave earlier in this thread are for companies that offer goods and services that vastly improve what the OEM's had to offer.  Maybe the OEM's have responded by now with their own offerings, but your boiler may or may not have had some of those features incorporated yet.

I had a client that had a waste wood fired boiler, bark, sawdust and planer shavings, who did not have a single soot blower in his boiler.  Seems whoever built it for him just didn't put them in.  It was a used boiler, and old Springfield, and tough as nails, and had started out its life as a coal fired boiler in Anderson, IN as one of a right hand / left hand boiler set, both with soot blowers.

Both boilers ended up in the same southern state about 90 mi apart each on its fourth owner each about 40 years old when it got there.  Both burnt wood, but one burnt hardwood while the other burnt pine waste.  One still had its soot blowers, and I could not convince my client, the owner of the one without to add soot blowers.  He used the boiler for about 20 years without them, while every other single wood fired boiler in the region that I knew of all had soot blowers, so go figure.

Much as I tried, (it would have been a nice project for me to engineer for him) I could never argue with his years of success without them.

Now, regarding coatings; coatings are extensively (or were) in black liquor chemical recovery furnace wall tubes to reduce corrosion and erosion.  They worked well, but they had to be replinished over time.

I'm still from Missouri regarding coatings reducing the need for soot blowers.  Now, making the effectiveness of sootblowers better, I can buy that.  I can't see how a piece of ash, above its ash fusion temperature would know to say 'oh, that tube is coated, so I can't land and stick there-I'll just keep going and find somewhere else to set down and stick.'  I could see it with dry friable ash below the ash fusion temperature.

One of the costs of sootblowing is erosion damage to boiler tubes done by the moisture in the soot blowing steam.  Besides the direct cost of generating steam for soot blowing, this is one of the costs of SB operation.

As you state, dave472005, superheated and saturated steam are both used among the other media that you mention.  Superheated steam has less problems with moisture once the piping to the SB and the SB feed tubes and lances are up to temperature.

But, even in a SH steam system, when the blowers are at rest, no matter how good the pipe insulation, the piping cools off, and moisture forms, just to be picked up and carried to and through the SB's when the start, and new moisture forms until the piping comes back up to temperature, wreaking havoc on the SB components and adjacent boiler tubing.

One idea I have had that I never could sell to management was to heat trace the SB supply piping so that the piping was maintained at or above saturation temperature for the steam, and steam entering the SB piping upon initiation of the SB cycle would be running in hot piping, not warming up the piping by giving up its heat to make more moisture.

It is an expensive idea on its face, but when compared with boiler tube replacement, worst case, or pad welding in the zones, every outage, best case, I always thought it was a viable option.  It would typically take one of the higher temperature types of heat trace, possibly even the mineral insulated type.

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