Horizontal coal-fired hot water boilers feature a single-drum longitudinal design. Water wall tubes are installed on both sides of the furnace, forming wing-shaped flue passages. Screw-type smoke tubes are arranged inside the drum, utilizing a movable grate with minimal coal leakage. This rational structure ensures high thermal efficiency and significantly reduces energy consumption.
Horizontal coal-fired atmospheric steam boilers, hot water boilers, gas boilers, oil boilers, and coal boilers all fall under the category of energy-efficient and environmentally friendly boilers. They adopt a single-drum longitudinal three-pass water-tube and fire-tube structure, with densely packed smooth-tube water-cooled wall tubes on both sides of the furnace. The design is rational and compact. With a large heating surface, extended flue gas flow path, and excellent heat transfer efficiency, these boilers achieve low flue gas temperatures, resulting in high thermal efficiency, low operating costs, and greater economic viability.
Compared to vertical coal-fired boilers, horizontal coal-fired boilers offer more pronounced advantages. Vertical coal-fired boilers employ a water-cooled bent tube structure for the furnace, with the furnace shell surrounding it, providing a large heating surface area. However, in horizontal coal-fired boilers, fuel burns on the grate, and the flames pass through a low wall into the combustion chamber. From there, the gases travel through wing-shaped flue ducts on both sides to the front smoke box, then through the tube bundle to the rear smoke chamber. Finally, the induced draft fan draws the gases through the chimney and into the atmosphere.
This design not only shields the boiler shell bottom from high-temperature radiation but also reduces inlet flue gas temperatures at the tube sheet inlet. Combined with return water ejectors, it eliminates stagnant water zones beneath the drum, effectively preventing tube sheet scaling due to subcooling or boiling, as well as furnace bottom bulging. The flue gas diversion into the smoke chamber aids dust removal and lowers initial dust emission concentrations.
Furthermore, the coal-fired boiler features a compact layout with a small footprint, facilitating transportation. It is shipped as a factory-assembled unit, resulting in a short installation cycle, low installation costs, reduced capital investment for users, and rapid return on investment. Additionally, the horizontal coal-fired atmospheric hot water boiler is equipped with sufficiently large manholes at the top, allowing personnel to enter the boiler interior for inspection and maintenance. This significant convenience is another key reason why factories increasingly favor horizontal boilers.
