water tube boiler sand blast 3

[hyl]

hello member
in our boilers we use crude oil firing as the main fuel and that result in many and hard depoist on the side wall of the boiler .the chemical cleaning we use is not efficant for removing the depoist so we use sand blast it is good and efficant ..the question is that-- is the sand blast has side effect on the boiler tube .and is that methode is normal for cleaning .
thankx for reply
hyl

jamil a alshahed nama
hartha power station

 

[gr2vessels]

jamil,
The silence of the people around you in this forum is a sign of some astonishment;- asking advice on any kind of blasting in an Iraqi power station is a delicate situation. As any blasting, you tend to remove the goodies and the bad ones. You remove the bad sooth form the tubes, but you remove some of the tube thickness also. The impact of the particles on the tube surface is not a great idea either, since the clean surface has been ruffed up and the new sooth will have a greater adherence to the tubes. Also, there could be other issues like accelerated corrosion / erosion of the new ruff surface of the tubes, which could go bang unexpectedly (sic.) I'm not sure of any cost issues at this particular power station, but if you could keep a few sets of tubes for replacement, that could help.
cheers,
gr2vessels

 

[MJCronin]

jamil..

You state that you use "crude oil firing as the main fuel" ?....Wow....

Are we also to understand that your boilers may have burned a variety of heavy fuels including crude ?

In my opinion, you probably have no other choice than sandblasting. There may be a technique or blast media that would be best for your particular situation.

The primary reason that most other boilers burn oil refined at least to minimally Number 6 quality is so they do not have to go through the extensive blasting, cleaning and probably boiler replacement that you are now going through.

As we undersatnd the situation, the world bank has finally (3/30/07) decided to fund changes and improvements to Iraq's electrical infrastructure (

http://www.iraqdirectory.com/DisplayNews.aspx?id=3524).

What kind of fuel will you be burning after the boiler is all cleaned up ?

-MJC

 

[chief]

Why not use a steam blaster or a high pressure water wash. Will not cause the same kind of damage as a sand blast. Been using crude in Marine boilers for years. There are proprietary chemicals on the market which prevent the build up on the tube walls.
We also used a steam atomiser in our fuel burners, to improve combustion. Are you heating your oil close to 100 degree C to get good atomisation and is your air supply temperature correct. Apears to me you are operating at either low fuel temp or low air temp to get these deposit problems. You need a burner specialist to look at the system.

Offshore Engineering&Design

 

[hyl]

Hello MR chief

Thank you very much for you good advice .MR CHIEF i want to ask you some question about your coment.
1-the proprietary chemical in your coment used as addative to the crude oil to prevent builtup .or used as cleaning agant .(can you guide us to this chemical please).
2-In our boilers heating of crude oil to hight tamperture 80C CAUSE the burner tip to block because asphlat and salt in crude oil evaperate in the burner tip and the resduile block the burner spray hole .
3-you think that if we rise the crude tamperture to 100C we get good result please (from your experance).
4-Can you give us some coment on steam blast for furnace size (10m width and 30m hight) i mean the methode of doing the job please.

thankx for reply.

jamil a alshahed nama
hartha power station

 

[chief]

I used a proprietary chemical supplied by Drew chemicals,but cannot remember the brand name offhand. To remove the salt from your crude , the practice is to use a centrifuge with a good fresh water wash. Your fuel day tank should have sufficient capacity to allow salt water to settle and be drained
You can expect your burner atomisers to choke up on a regular basis. You need a spare set to change out about every 12 hours and have your operators trained to clean the atomisers correctly.
It seems to me you have very poor atomisation and the problem is not your crude. A simple check is to see if you have a black smoky exhaust.Too much black means too much fuel, too much white means too much air.
Have you got a good balance between your air supply and your fuel.
Use the smallest size atomiser tips as possible to maintain your boiler pressure constant.
Instead of going for major equipment changes, such as investing in steam /fuel atomising system., order up a spare set of burner and atomiser tips. Train your operators in the good practice of cleaning them and get your fuel oil temperature to 100 degree C.
Ensure your fuel pressure is sufficient to give good atomisation.
Take care of the simple things and the big bangs do not happen.

Offshore Engineering&Design