Water-tube Boilers

In a water-tube boiler the water is inside the tubes and combustion gases pass around the outside of the tubes. The advantages of a water-tube boiler are a lower unit weight-per-pound of steam generated, less time required to raise steam pressure, a greater flexibility for responding to load changes, and a greater ability to operate at high rates of steam generation.

A water-tube design is the exact opposite of a fire-tube. Here, the water flows through the tubes and is encased in a furnace in which the burner fires. These tubes are connected to a steam drum and a mud drum. The water is heated and steam is produced in the upper drum.

Large steam users are better suited for the water-tube design. The industrial water-tube boiler typically produces steam or hot water primarily for industrial process applications, and is used less frequently for heating applications. The best gauge of which design to consider can be found in the duty in which the boiler is to perform.

Water-tube boilers:

• Are available in sizes far greater than a fire-tube design, up to several million pounds-per-hour of steam
• Are able to handle higher pressures up to 5,000 psig
• Recover faster than their fire-tube cousin
• Have the ability to reach very high temperatures

Disadvantages of the water-tube design include:

• High initial capital cost
• Cleaning is more difficult due to the design
• No commonality between tubes
• Physical size may be an issue

Дата добавления: 2015-08-03