The difference between fire tube boiler and water tube boiler


The difference between fire tube boiler and water tube boiler

Boilers are thermal energy equipment widely used in industrial production. Split according to the flowing medium inside the boiler, it can be divided into water tube boiler and fire tube boiler. When the user selects the boiler, the performance of the two boilers is unclear, which brings a lot of trouble. Here, we will give you a detailed list of the characteristics of the two boilers for the user's reference.

1.Fire tube boiler


Fire tube boiler, also known as shell boiler, the flue gas generated after fuel combustion is circulated in the fire tube or smoke tube to heat the water, steam or steam-water mixture outside the fire tube or smoke tube to provide stable heat energy. Mainly consists of pot shell, furnace tube, smoke pipe, smoke box, combustion equipment, etc. This structure has been used for a long time in the field of industrial boilers, and there are many types of structures. For example, it can be divided into vertical boilers and horizontal boilers according to the placement of the drum. The rated power of the vertical boiler is 0.2t / h ~ 1.5t / h, and the rated power of the horizontal boiler is 2t / h ~ 3-t / h

Taking a horizontal coal boiler as an example, the working process can be briefly described as follows: After the fuel burns on the grate, the flame passes through the low wall to the embers chamber, from the embers chamber through the wing-shaped flues on both sides to the front smoke box, It is bundled from the smoke tube to the rear smoke chamber, and then drawn by the induced draft fan through the chimney and discharged into the atmosphere. There is no dead water zone at the bottom of the drum, which can also effectively prevent the tube sheet from scaling due to over-cooling and boiling, and the convex bottom of the furnace. The flue gas can be turned to the smoke chamber to remove dust and reduce the original dust concentration.


1) Simple structure, large steam volume, good adaptability to load.

2) It has lower requirements on water quality and is mostly used for heating and heating of enterprises and households with low power requirements.

3) At the same power, the volume is smaller than a water tube boiler.

4) The furnace liner can adopt a three-pass vertical large furnace structure, which increases the area of  the flue tube and the radiation heat absorption of the furnace.

5) Large heating area, high thermal efficiency, sufficient water supply and small boiler room area.

6) Mainly used in chemical, textile, food, building materials, pharmaceutical and other industries


2. Water tube boiler


Compared with fire tube boiler, water tube boilers refer to an industrial boiler in which the combustion chamber and the heating surface are arranged outside the drum, water, steam or a mixture of both flows in the tube, while flame or flue gas flows outside the tube and burns. . It consists of two parts: the body and the auxiliary machine. The former includes drums, headers, water-cooled walls, convection pipes, economizers, super-heaters, burners, furnaces, flues, air pre-heaters, etc.; the latter includes blowers, induced draft fans, multi-tube dust collectors, centrifugal pump, slag remover, coal loader, etc. Commonly used structural forms include water tube boilers, straight water tube boilers, and curved water tube boilers.


1) Wide working pressure range, meeting the conditions above 2.5MPa.

2) Large rated power, can meet the requirements of more than 15t/h.

3) High efficiency heat transfer element-threaded flue pipe with reasonable flue gas flow rate to make boiler thermal efficiency higher.

4) High requirements on water quality.

5) The combustion chamber is large and the fuel applicability is strong.

6) Gasification combustion technology, a gasification rotary combustion chamber is set up, and a secondary swirling air distribution is built in to make fuel combustion more fully.

7) Equipped with PLC automatic control equipment, the degree of automation in the boiler operation is relatively high.