Boiler huffing

[POPPASMURFF1942]

Good morning Gentlemen and Ladies. The problem is I have a 100K pph natural gas boiler that will only turn down 2 to 1. The problem stems from the fact that at the lower rates the pressure in the fire box/furnace area swings from +2.9 wc to -1.2 wc at 50K pph. At 40K pph the swing get worse +2 to -3.6 WC. The burner and fuel gas pressures are very stable. The wind box pressure swings a little due to the furnace pressures swinging. Now this is where I am looking for expertise. This boiler has a 72" stack that is only 8 feet tall. What I am thinking is that if the stack were much taller with a conical top swages in to 48" diameter or a Cooley hat top that would not allow back flow would solve my problem. Any thoughts, sizes or recommendations.

 

[MJCronin]

Smurf....

Was the startup crew responsible for first-fire competent ?

The boiler should have been run through it's entire operating range at commissioning time.

Oh, wait.... your company just bought the plant, site unseen .... all records and drawings were discarded by the previous owner.

....and your MBA boss wants you to "straighten things out".... harummmmphhh...

MJCronin
Sr. Process Engineer

 

[POPPASMURFF1942]

Boiler has been in service for 19 years with the inability to turn down more that 2 to 1.

And a ragged as it runs at lower rates of 50 to 60K they have just been running it at 80 +.

Rather than cure the problem they just lived with it.

Now as to your comment, There are new managers in the plant and they want things to operate as designed,

My experience with boiler operation, maintenance, rebuilding and problem solving goes back 30 plus years.

And from time to time I rely on the expertise of others in some areas that help me make the correct decision.

If you can enlighten me on to what else may cause the huffing other than a lack of a continuous laminar flow from the stack please make it known.

I thank you in advance for your valued input.