Boiler Water Treatment Equipment

Water Softening

Due to high levels of calcium and magnesium, many types of equipment fail to work properly, which can lead to an increase in energy costs and/or complete failure of the equipment. Many plants use water softeners for boiler feed, cooling towers, entire water supply and various types of process water.

When using industrial water softeners for boiler feed, there are several commons factors that go into design:

1. Boiler HP
   • The rating of small boilers is by horsepower.  One horsepower is the ability to evaporate 34.5 lbs. of water into steam at 212 degrees F and above.
   • Example 1:  100 hp x 34.5 = 3450 lbs. of steam per hour
   • Example 2:  8625 lbs. of steam / 34.5 = 250 hp boiler
2. Condensate return
   • Steam transfers its heat and then reverts to a liquid phase called condensate.  To improve the plants energy efficiency is to increase the condensate return to the boiler.
   • A common efficiency benchmark for condensate return is 90%. 
3. Operating pressure
4. Water hardness
   • Water hardness is composed of calcium (Ca) and magnesium (Mg).
   • The problems that can occur are mainly scaling which reduces efficiency on boilers.

Boiler feed typically consists of alternating water softeners to allow a continuous feed of soft water. Because of the efficiency of boilers, capacity and not flow rate is the main issue in designing the water softener system. The higher the operating pressure of the boiler, the more stringent the water quality requirements will be.

Reverse Osmosis Systems

Traditional reverse osmosis systems used for boiler feed operate with a feed pressure of 200 psi to 400 psi.  The reason boiler feed may require reverse osmosis is that for some applications, water softeners do not produce adequate water quality.  Even though water softeners remove calcium and magnesium, they do not reduce TDS.  To reduce TDS for boiler feed a reverse osmosis system is required.  High pressure boilers are the most common application that requires a reverse osmosis system.  One of the best resources for boiler feed water quality parameters is the manufacturer.  They have specific criteria that they can provide to you which will give you a great foundation to designing a boiler feed reverse osmosis system.