Steam boilers can be divided into electric steam boilers, oil-fired steam boilers, gas-fired steam boilers, etc. According to the structure, they can be divided into vertical steam boilers and horizontal steam boilers. Small steam boilers are mostly single-return and double-return vertical structures, and large steam boilers are mostly three-return horizontal structures.
Vertical double return structure
Vertical oil-fired and gas-fired steam boilers adopt the burner down mode, two-way structure, full combustion of fuel, stable operation of the boiler; there are spoilers inserted in the flue pipe to slow down the exhaust gas speed, increase heat transfer, high thermal efficiency of the boiler, and reduce the user's use cost.
Horizontal three-return structure
Horizontal steam boiler is a three-way downstream pyrotechnic tube structure with full wet back and shell. The flame burns under micro-positive pressure in large combustion chamber, extends completely, has low combustion heat load and high combustion heat efficiency. It effectively reduces the exhaust gas temperature, saves energy and reduces consumption, and is economical in use. The structure of corrugated furnace gallbladder and threaded flue gas pipe not only improves the heat absorption strength of the boiler, but also meets the need of heat expansion on the heat exchange surface. It is scientific, reasonable and durable.
Heating equipment (burner) releases heat, which is absorbed by the water wall through radiation heat transfer, boiling and vaporizing water in the water wall, generating a large amount of steam into the drum for steam-water separation (except for the once-through furnace), and the separated saturated steam enters the superheater, and continues to absorb the top of the furnace, horizontal flue and tail smoke through radiation and convection. The flue gas heat of the flue gas and the superheated steam can reach the required working temperature. Power generation boilers are usually equipped with reheaters, which are used to heat the steam after working through the high pressure cylinder. The reheater steam goes to the medium and low pressure cylinders to continue to work for power generation.