You Need What You Need
What you want isn’t always what you need. A 900-hp supercar sounds like fun. That is, until you get your first insurance bill. Ice cream for dinner every night sounds like a dream, but when your next physical rolls around, your doctor may have some bad news. When it comes to the boiler business, a 1,900 hp boiler may sound like the kind of powerful workhorse your factory needs, but as it turns out, it may be too much of a good thing. You might need something less, and that’s a good thing to know.
That’s just one of the factors to consider when renting or replacing a boiler. As WARE Rental Division Vice President Steven Taylor puts it, “Don’t just to look at the size of the boiler and swap in the same size. I mean, anybody can do that. You have to know what you’re looking for.”
A Look Back
Taylor recommends keeping a few factors in mind, starting with the boiler’s history. That’s not just about age and wear, either. That boiler’s been there for a long time, and your company’s probably changed a bit since then. You need to confirm that you have the same steam demand you did when the boiler was first commissioned. What may have been plenty of steam back then may just be barely enough – or not enough – today.
Share the Load
It's also important to consider any change in heat load on the boiler as well, and whether the current boiler was able to handle it. For example, if your feedwater temperature has changed since the boiler was installed, the new boiler is going to have to be able to produce more heat to compensate. This means seasonality also comes into play. “A boiler installed in August may just be handling process load and nothing more. But you put in a boiler in the middle of January, and you’ve got the heat load from cold utility water, cold air through the dampers, and a colder operating environment.”
Colder temperatures also mean greater heating load on boilers that supply environmental heat as part of their work processes. So season to season, it just can’t perform the same. It’s best to play for the worst conditions when you get a replacement, so you’ll have plenty of steam every and any time you need it regardless of the temperature outside.
Fuel in. Steam Out.
Changes in your fuel supply can also affect whether your old boiler is a proper indicator of what your next boiler should be. If you’re operating with a different fuel, or if the fuel quality has shifted, you’ll have to take that into account when specifying a replacement. Otherwise, you may end up with more heat or less heat than your plant needs.
Track Record
According to Taylor, past boiler performance is also a key indicator of what the next boiler should look like.
“Let’s say a customer calls us and wants us to quote a 75,000 pound-per-hour boiler. That may be what they need, and we’ll quote them for that, but we’ll also take the time to ask about how their previous boiler was operating. If they tell us ‘well, it never really got out of low fire, soooo’ we know their previous boiler was oversized, and not operating at its highest efficiency. In that case, we’ll quote them something that will deliver all the steam they need, but at greater efficiency.”
Add-Ons
Another important consideration when sizing a new or rental boiler has to do with whatever else is in your system, particularly if it’s a deaerator. The function of a deaerator is to remove excess air and oxygen from your boiler’s water supply. It does this by blasting the water with steam to release trapped air. Where does that steam come from? That’s right, your boiler. So if you don’t take the steam demands of auxiliary equipment into consideration, your new or rental boiler won’t be properly rated for your actual steam demand.
“Deaerator demand can take up to 10% of your boiler’s output,” says Taylor. “So if you look at your steam flow recorder and it says 75,000 pounds per hour, and you replace it with a 75,000 pound-per-hour boiler, once you bring those deaerators online you’re only looking at 67,500 pounds per hour of steam that actually makes it to your work processes.”
Look Ahead
Another important consideration when specifying a new or rental boiler involves thinking about the future. What might be the ideal boiler today may be inadequate for your steam demand in 10 years. Or even five. Consider growth, then, when you’re considering what goes in your boiler room.+
Not Just Boilers
Knowing the actual size boiler you need goes beyond just replacement of the boiler itself. Any equipment replacement, from water softeners to deaerators to economizers, has to be properly matched to the actual boiler, in the actual operating conditions, under actual real-world demand. That means more than just reading the boiler manual or a few engineering documents. It means applying real-world boiler expertise to make sure your new equipment will do what you need it to, and do it well, so your boiler operates at its most efficient.
These are the kinds of things to keep in mind when looking at a new or rental boiler. But they’re also proof that WARE is the only place to go for a new or rental boiler, because we think to ask the important questions. Whatever you need, from a rental to a new boiler to service and maintenance, we’re here to help. We also have the nation’s largest online boiler parts store, BoilerWAREhouse.com, for all the parts and supplies you need, with shipping to anywhere in the country in about 2 days or less. No matter what you need, we’re here to help.