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Know the Basics of Water-Tube Steam Boilers

Water-tube boilers are highly efficient machines that, by their design, produce superheated dry steam at very high pressures. They are the kind of boilers capable of feeding the processes of heavy industry and utility companies

This article contains succinct technical descriptions of the steam production process in water-tube boilers. If you want a summary, go directly to the CONCLUSION section.

Design

steam boilers
Water tubes within the boiler’s furnace.

Water-tube boilers have water-containing tubes heated externally by the fire produced in a furnace that burns gas or another type of fuel. As a result, they produce steam by transferring the heat received to the water circulating inside them. Next, the resulting steam feeds industrial processes downstream. Water-tube boilers hold the pressured steam in the tubes, hence their large size. They have a steam capacity of 4,500 – 12,000 kg /hr, with very high pressure.

Operation

In general, the water tube boiler design includes several drums. Specifically, the lower water drum and the upper steam drum, which are connected by tubes that form the furnace and convection section. The tubes that make up the furnace walls, receive the heat and transfer it to the water contained in them, producing steam. Afterward, the hot water rises and enters into the upper steam drum, where the saturated (wet) steam exits off the top of the drum to feed processes or to produce superheated steam.

Efficiency

Water-tube boilers are highly efficient for various reasons:

  • The steam reenters the furnace through a superheater to generate extra pressure. In particular, this device heats the saturated steam above the boiling point at very high pressure, turning it into superheated dry steam, which leaves the boiler with pressure high enough to drive large turbines.
  • They recirculate the water left at the bottom water drum to pre-heat the feedwater supply.
  • The exhaust gases return to pre-heat the air blown into the furnace, making up an even draft that heats the boiler’s feedwater supply.
  • These systems have a BTU input ranging anywhere from 500,000 to over 20,000,000. As a result, water tube boilers can provide high-speed steam capabilities and fast response to changing demands due to the relatively low water content.

Uses

Industrial water-tube boilers typically produce steam or hot water primarily for industrial applications that require high pressured steam to drive their processes. For instance, the large turbines of utility companies. They are used less frequently for heating applications.

Conclusion.

Water-tube boilers are highly efficient machines that, by their design, produce superheated dry steam at very high pressures. They are the kind of boilers capable of feeding the processes of heavy industry and utility companies. However, the acquisition and installation costs are high. In the case of heavy industries, they are custom made on the installation site, which can be complicated and time-consuming. Furthermore, they are challenging to maintain. Thus, they require highly skilled personnel for operation and maintenance. If you need advice or assistance on the complexities of the installation, operation, and maintenance of water-tube boilers, contact our steam team here.

Sources: Superior Boilers

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