What is the difference between a water tube boiler and a fire tube boiler?

Some industrial boilers are water tube boilers and some are fire tube boilers. Both types of boilers are very common. What is the difference between water tube boilers and fire tube boilers? The boiler shell and drum are the main components of the boiler body. What do they mean?

Ⅰ. Water tube boiler and fire tube boiler

The water pipe and the fire pipe are defined by the difference in the medium inside the pipe. The characteristics of the boiler are obvious. The water pipe is the water flowing inside the pipe, and the water in the pipe is heated by external flue gas convection/radiation heat exchange. The fire pipe is the flue gas flowing inside the pipe. Let the flue gas heat the medium outside the tube to achieve heat exchange. The fire tube boiler has a simple structure, large volume of water and steam, good adaptability to load changes, and lower water quality requirements than water tube boilers. It is mostly used for small-scale enterprise production processes and domestic heating. superior. The heating surface of the water tube boiler is conveniently arranged, and the heat transfer performance is good, and it can be used in the working conditions of large capacity and high parameters in structure. But it has higher requirements on water quality and operation level.

1. 1.The water tube boiler has a wide range of pressure adaptability, can break through the pressure limit, and can meet the steam supply requirements above 2.5MPa. Fire tube boilers are limited by material wall thickness and pressure, and are used for pressures below 2.5MPa.
2. 2.Fire-tube boilers are shell-type boilers. Due to the limitations of equipment and tooling of various boiler manufacturers, it is difficult to manufacture fire-tube boilers that are too large, usually below 35t/h. The water tube structure boiler can realize the large-scale boiler, and the boiler above 35t/h usually adopts the water tube structure.
3. 3.The fire tube boiler has the characteristics of compact structure. Under the same output, the shape and equipment weight are lower than the fire tube boiler. Due to the larger size of the water tube boiler, there is more space for arranging the superheater, so the water tube boiler occupies a relatively large boiler room.

Ⅱ. Boiler shell and drum

1. 1.The shell boiler is a small (generally) boiler, which is mainly determined by its structure. The combustion principle of the boiler is clear, mainly because the combustion system and the water vapor system are in the same "shell".
2. 2.The boiler drum is a cylindrical pressure vessel used for steam-water separation and steam purification in a water-tube boiler, forming a water circulation loop and storing boiler water, also known as a steam drum. The main function is to receive water from the economizer, separate steam from water, supply water to the circulation loop, and deliver saturated steam to the superheater. There is a certain amount of water in the drum, which has a certain amount of heat and working fluid, which can slow down the change of steam pressure when the working conditions change, and play a certain buffer role when the water supply and the load are not coordinated for a short time. The drum is equipped with internal devices for steam-water separation, steam cleaning, dosing in the pot, and continuous sewage discharge to ensure steam quality.

The water tube boilers, fire tube boilers, boiler shells and drums have been explained in detail above. I hope you can learn more about boilers through this article. Whether it is a water tube boiler or a fire tube boiler, they are very popular among users. If you have a boiler purchase plan, you can put forward the corresponding technical requirements, and our company will choose a suitable boiler for you.