Package Watertube Boilers

[superbee]

Why an 'O' type versus 'D' type watertube package boiler? What's the advantages or disadvantages? Also, why would one want a 4 burner design versus a single burner?

 

[rmw]

The type "D" has a single gas path through the generating bank while a type "O" has a dual path. Better symmetry especially if there is a super-heater bank at the end of the furnace. (Does it have super-heat?) Some benefit with respect to differential expansion of the furnace vs the generating bank, but that is minimal.

Now the 4 burners, I don't know unless it is either (A) a short furnace or (B) you specified a lot of turn down. That is easier to do with 4 smaller burners than one large one. Then again, it might just be the way the manufacturer designs their unit but I doubt it. It is cheaper to do it one time with larger components than 4 times with smaller components.

Type "O's" tended to be the larger higher pressure package boilers that I encountered while the type "D's" were smaller, lower pressure and lower capacity. But that may not be the rule, just my experience. Certain manufacturers made one type and others made the other.

rmw

 

[MJCronin]

super...

"O" type boilers are constructed to offer high output at minimum width. The narrow configuration facilitates transportation by truck or railcar making these boilers attractive in rental services.

An excerpt from the Cleaver-Brooks "Nebraska" boiler website:

"NOS-1A: 10,000-40,000 lbs/hr
NOS-2A: 40,000-80,000 lbs/hr
NOS-3A: 80,000-150,000 lbs/hr
CAPACITIES DESIGN PRESSURE STEAM TEMPERATURES
10,000 to 150,000 lbs./hr 200 to 1,500 psig to 1,050°F

The rugged O-Style boiler design has become the true workhorse of the rental boiler industry. Its symmetrical design is ideally suited for mounting on a trailer for over-the-road transport. Our line of rental units continues to provide efficient & reliable service year-after-year while withstanding rapid emergency start-ups."

"D" type boilers are somewhat cheaper, but wider....

My opinion only

MJC

 

[macmet]

I'm wondering if four burners compared to one is for turndown. Is it possible the efficiency of the burner itself is low at 25% making a smaller burner at 100% a better option.

Also wondering if the D type has limitations as far as installing the units b/c of the centre of mass being off of the centre-line.

What I do know is neither of these type of boilers should be used with a solid fuel.