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yendamuri
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Join Date: Sep 2012
Location: Srikakulam, Andhra Pradesh
Posts: 6

Modifications on Boiler ID Fan

10/08/2012 6:45 AM

Hi! I am back with a new issue.

Have a centrifugal fan (Boiler ID) of 120,000 m3/Hr capacity, handling a max of 80,000 m3/Hr of Boiler flue gases. Fan discharges max head 2.3 kpa at 980 rpm.

The fan has central suction and side ways delivery at 40 deg angle.

We plan to rotate the fan delivery to vertical (delivery right on top) and take discharge to process utilisation (Y connection), whenever requirement arises. Normally the discharge let in to atmosphere through a 42m stack.

Is it technically feasible, to derive the planned outcome. The discharge to travel for about 80m (approx) for process utilisation. Ducting size would be 1400mm dia.

Thank you very much for your time.

Regards

YK Rao
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Pathfinder Tags: Centrifugal Fan - Modifications to Delivery orient
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#1

Re: Modifications on Boiler ID Fan

10/08/2012 6:49 AM

14ms-1 is a bit high. Consider using a larger duct size.

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yendamuri
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Join Date: Sep 2012
Location: Srikakulam, Andhra Pradesh
Posts: 6
#2
In reply to #1

Re: Modifications on Boiler ID Fan

10/08/2012 7:05 AM

Dear Mr Slack,

Can't follow, larger ducting for process usage?

And what about reorienting the fan delivery, does it not affect the fan performance adversely?

Thanks & Reg

YK Rao
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#3
In reply to #2

Re: Modifications on Boiler ID Fan

10/08/2012 7:47 AM

<...larger ducting for process usage?...>

1.4m Ø is a bit on the small side for this duct as the velocity is above 10ms-1.

<...reorienting the fan delivery, does it not affect the fan performance adversely?...>

Reorientating the fan delivery doesn't affect the performance of the fan. It affects the ability of the duct to pass whatever the fan is putting into it, putting the operating point at a different place on the fan manufacturer's published performance curve. Please post a general arrangement drawing of the duct, "before" and "after" reorientation.

<...Mr...>

How abstruse.

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Arun 54
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Join Date: May 2007
Posts: 12
#5
In reply to #2

Re: Modifications on Boiler ID Fan

10/09/2012 5:24 AM

As already mentioned, the ducting size of 1400mm dia will lead to velocities in the range of 14.5m/sec. even on 80,000 cu.m./sec flow rate, which will lead to high pressure drop if the total quantity of gases are to be diverted. So, either the ducting size to be increase to say 1600mm dia and above or keep some flow going towards the normal route by using damper valves. Direction change will not effect the performance as long as the blower is discharging into acceptably sized outlet.
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yendamuri
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Join Date: Sep 2012
Location: Srikakulam, Andhra Pradesh
Posts: 6
#6
In reply to #5

Re: Modifications on Boiler ID Fan

10/09/2012 6:37 AM

Dear Mr Arun, thanks for comments.
<.. 80,000 cu.m./sec flow rate..>,
Flow is /hr, this will not alter the gist of your comments, or does it!
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ducon
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Join Date: Dec 2006
Location: Hop around Toronto, New York & Karachi
Posts: 1876
Good Answers: 19
#4

Re: Modifications on Boiler ID Fan

10/08/2012 11:58 PM

Why not ask the Boiler Supplier? This is a Boiler issue and under the Chief Boiler Inspector. You simply cannot decide and do it on your own. Better you ask him first and present all your calculation/drawings for his approval or as a registered Boiler Contractor to do the same after getting approval from the Boiler Inspection Deptt.

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Users who posted comments:

Arun 54 (1); ducon (1); PWSlack (2); yendamuri (2)

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