Water wall, as the name suggests, is to cool the wall with water.

In the early boilers, there was no heating surface in the furnace, and water-cooled pipes were later arranged to protect the furnace wall from being burned by high temperature flue gas and to cool the combustion products.

These are arranged around the furnace, the flow medium in the tube is generally a mixture of water or soda water, and the heating surface cooled by water is called the furnace water cooling wall.

There are two main types of water wall, namely light tube water wall and film water wall.

classification

According to the structural type, there are three main types: plain tube type, membrane type and squeaked tube type.

The plain tube water wall is composed of a whole row of seamless steel pipes, and their structure is the simplest; the membrane water wall weld many rolled water-cooled fin tubes together with spot welding, so that they become a sealed combined heating surface, which can not only improve the air tightness of the furnace, reduce air leakage, but also better protect the furnace wall, reduce the weight of the furnace wall, simplify the structure; the water wall of the spur tube is to weld many pins with a length of 20~25mm and a diameter of 6~12mm on the water-cooled wall tube, and then apply chrome ore refractory plastic in order to reduce the heat absorption of this part of the water wall and increase the temperature of the combustion zone, it is suitable for occasions where fuel ignition is particularly difficult or some liquid slag discharge furnaces.

According to the layout part, there are two kinds of attached wall type and partition wall type (i.e., double-sided heating) water cooling wall.

The former is mostly partially embedded in the inner wall of the furnace wall and absorbs heat on one side, while the latter is mostly installed in the middle of the furnace chamber of a large boiler, separating the whole furnace into two independent parts that are heated on both sides.

Advantages of membrane water walls

(1) Ensure the tightness of the furnace wall and reduce the air leakage of the combustion chamber.

(2) The combustion chamber is fully water-cooled, which is conducive to preventing coking in the case of intensified combustion.

(3) The heat storage capacity is small, the combustion chamber heats up quickly, and the cooling is also fast, which can shorten the cooling time of boiler start-up and shutdown.

(4) It is suitable to use the pipe-laying furnace wall, which greatly reduces the load of the boiler frame and is convenient for suspension.

(5) Compared with the plain tube, the heat absorption capacity of the tube is improved.

(6) It improves the degree of pre-assembly of boiler parts, which is convenient and reduces the installation workload.