7 December 2015
 Categories: , Articles

Are you doing everything you can to protect your temporary boiler from rust and corrosion? Find out by checking the below 3 common rust-related mistakes made with temporary boilers.

1. Since You Don't Own The Boiler, You're Not Worried About Rust

Deaerators are the primary method of protecting your temporary boiler from rust and corrosion. As your boiler operates, it loses water due to steam output and boiler blow-down. You need to replace this water with make-up water, but fresh make-up water is rich in dissolved oxygen, and oxygen is a huge contributor to boiler pipe rust and corrosion. A deaerator raises the temperature of incoming make-up water, and as that temperature rises, the water can no longer keep its oxygen molecules dissolved. As a result, the oxygen molecules rise from the water as gas and are vented out and away from the boiler.

But it usually costs a bit more to have your temporary boiler fitted with a deaerator, and you're only going to need the unit for a short time. Surely rust won't build up in the limited amount of time the rental boiler is under your operation, right? Wrong. When heat, water, and oxygen come in contact with iron, the formation of rust can be an immediate reaction; the metal pipes in your temporary boiler can start to corrode the very second oxygen-rich make-up water comes in contact with them. Whether the boiler belongs to your or a rental agency, and whether you'll be using it for a short amount of time or for the next 30 years, you need a deaerator.

2. You're Relying On A Deaerator To Rid Your Make-Up Water Of Oxygen

If you're using a deaerator with your temporary boiler, good for you—so far so good. But you should be aware that the deaerator won't remove all of the oxygen in your make-up water. Most deaerator devices will bring the oxygen concentration of your make-up water down to 7 parts per billion, but you'll need the help of oxygen-scavenging chemicals to remove the rest. 

What kind of oxygen-scavenging chemicals? Powder sodium sulfite is an effective dissolved oxygen remover if your system is operating below 1000 psi. For systems that exceed 1000 psi, use hydrzaine for dissolved oxygen removal. If you're in the food processing business, stick with non-toxic sodium erythobate. All of these oxygen-scavenging chemicals are available in powder and granule form from a temporary boil rental agency, such as Nationwide Boiler. The amount of each chemical you should incorporate into your make-up water will be printed on the side of the oxygen-scavenging chemical containers.

3. You're Adding Oxygen Scavengers Directly To Your Water Feed Line

If you both have a deaerator on your temporary boiler and use oxygen-scavenging chemicals, you know your stuff when it comes to boiler rust prevention. The final consideration you need to make is where, exactly, you're adding your oxygen-scavenging chemicals. The longer the chemicals have to interact with your make-up water before that water is fed into your boiler, the more effective they will be.

Do not add your chemicals directly to the make-up water feed line. Instead, add them to a your storage water tank so the chemicals have plenty of time to work before they hit the make-up water feed line and enter your boiler system. 

Dissolved oxygen in your temporary boiler's make-up water can destroy the boiler, and it can do it fast. If you've got a rental boiler, protect it from rust and corrosion as if it were your own by springing on a good rental deaerator for the unit and adding oxygen-scavenging chemicals in the right amount and to the right place on your boiler system.