oversized cleaver brooks steam boiler

[peter1126]

I am a part owner of an industrial laundry and have a 150 hp cleaver brooks steam boiler with 6 million btu. We used to have the steam coil system in a presurized hot water tank to make our hot water. I just purchased a ludell direct contact water heater 2.2 million btu which took a lot of stress off of the boiler. The water heater is sized perfect for the usage but now the boiler is oversized. The boiler now starts and stops frequently during the process. Without purchasing a smaller boiler, what are my options?

 

[brandonb73]

Contact a local CB rep in your area, they should be able to help. You may be looking a derating your burner.

 

[pmover]

Options . . .

Yes, frequent thermal cycling of a boiler is not too good; although CB boilers are very good. Boiler life is strongly dependent upon the water quality and how well you maintain the operating & safety equipment.

That aside, some options are: 1) expand the use of the boiler and sell excess heat to neighboring businesses (can be risky, costly to maintain and install), 2) while a smaller burner is practical, modifications to the blower wheel & likely the motor will be needed, 3) sell the boiler to obtain a smaller boiler, 4) expand the laundry business, etc. Any choice that is made will end up costing you some money.

Good luck!
-pmover

 

[rmw]

You didn't say what pressure you are operating at, but if you are operating at high pressure and your equipment/process could operate at a lower pressure that could stretch out your run cycles.

150 HP sounds like a whole lot for a laundry.

rmw

 

[chicopee]

Lower the firing rate.

 

[skbutler]

Unless this is a high turndown CB boiler, it has a turndown of 3 to 1. In other words it is firing at 50 hp on low fire. If this is more capacity than you need, the boiler will cycle.

DO NOT reduce the low fire settings as doing so will over heat the burner and drastically reduce the life of the burner. If you are sure you want to change your CB boiler from a 50-150 hp boiler to lets say a 25 -75 hp boiler which would probably not cycle very much, then contact a professional burner/boiler service technician. If you want to do it yourself and I don't advise it, email me and I'll tell you how.

 

[macmet]

Could you stagger your heat demand, so it's peak is less, but it's more consistent. You'd run at a lower firing rate but over a longer period.

Or, install a storage tank, heat all your water for x hours, then only fire up when it's been used.

 

[peter1126]

Thanks for the information. I had a technitian run a combustion test on the burner. He made some small adjustments to the flame and lowered the setting on low fire. He said the flame was too strong before in low fire.
I was running between 92 psi and 105 psi. We also changed that to run between 80 psi and 105 psi as the change did not affect my production. Now when the boiler starts at 80 psi it is on low fire, after 25 seconds it adjusts to high fire then hits 90 psi and goes back to low fire until it hits 105 psi and stops. It is running better than before and is not cycling as much when my production is in full demand. It still cylcles at the end of the day when some of the steam dryers are not being used. I think that in the future my best option would be to downsize my boiler.
The combustion test is attatched
Thanks again for the help
Pete

 

[chicopee]

SKButler, back in 1986, I attended a week long seminar at the CB Lebanon facility,PA and their current burners had a 10:1. Prior to that the turn down ratio was 4:1.

 

[GenB]

CB should have a man pot, to keep fire at 50-60% lock it up and you will have
a very efficient 80-100 hp
below that is not economic as spend gas and also may create condensation.