Top Discharge Blow Tank for Fly Ash Handling

yu_ren2010
(not verified)
Posted in: , on 7. Sep. 2010 - 05:05

Problem of top discharge blow tank for fly ash handling

Dear all

Now we have one project, we use a top discharge blow tank for handling the fly ash, the volume of the tank is 16m3, and the discharge pipe is DN250, the horizontal distance is 300m, the vertical distance is 30m, contain 7 elbows, the dimension between the fluidizing menbrans is 150mm.

The volume of the fluidizing air is 22.5Nm3/min, and the volume of the supplementary is 35Nm3/min. But now the pressure at the fluidizing air pipe is 3.4bar (gauge pressure), and one cycle needs 15mins!

Can anyone tell me the reason? And How can I modify the system?

Thank you!

YuRen2010

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 7. Sep. 2010 - 09:24

Dear YuRen2010,

The capacity of your installation should be approx. 100 tons/hr at 2.5 bar and at a complete cycle time of approx 7 min.

Is the cycle time that you mention the total cycle time (including pressurizing and purging) or just the emptying time of the kettle?

The 3.4 bar underneath the fluidization cloth is too high.

Somewhere in the line there must be an unforeseen pressure drop.

First check the pressures at:

Compressor outlet

Booster outlet

Discharge tank

Discharge tank outlet

A drawing of the piping arrangement would be helpful.

Have a nice day

Teus

Teus

yu_ren2010
(not verified)

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 7. Sep. 2010 - 01:21

Dear Mr. Tues,

15 mins is the total time. And I though whether the dimetion from discharge pipe to the the fluidizing menbrans is too high (150mm). If this dimension is high, what will happen? and if this dimension is short, what will happen?

Best Regard.

Yuren2010

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 7. Sep. 2010 - 02:21

Dear Yuren2010,

A 6" pipeline for 22.5 m3/min is Ok.

A smaller diameter would increase the pressure drop over this pipe.

Have you checked the parameters, mentioned in my previous reply?

BR

Teus

Teus

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 8. Sep. 2010 - 06:37

You need to look at the fluidising membrane. Is it blind ? or the material has passed to the clean side and blocked?

Without fluidising air the cycle we take very long.

Mantoo
yu_ren2010
(not verified)

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 19. Sep. 2010 - 09:24

Dear all,

Thank you very much for your help! Now the problem is solved. I modified the distance from the discharge pipe to the fluidizing menbrans, than it is OK!

Yuren2010

Re: Top Discharge Blow Tank For Fly Ash Handling

Posted on 19. Sep. 2010 - 11:28

Dear Yuren2010,

Thanks for the feed back. Very much appreciated.

I now understand that you were referring to the distance between the fluidizing cloth and the intake of the discharge pipe, rather than the diameter of the discharge pipe.

Can you tell us how you discovered that that was the cause of the problem or did you just try a modification and found out?

Have a nice day

Teu

Teus