Direct-current coil boiler with overheating section located in hearth

The invention is applicable to the technical field of direct-current coil boilers, and provides a direct-current coil boiler with an overheating section located in a hearth, which comprises a boiler shell, a steam-water separator and a spray desuperheater, a burner connector is arranged at the lower end of the boiler shell; a smoke outlet is formed in the upper end of the boiler shell, and an economizer flat coil pipe, a coil pipe water-cooled wall spiral coil pipe, a hearth water-cooled wall spiral coil pipe, a hearth water-cooled wall low-temperature overheating section and a hearth water-cooled wall high-temperature overheating section are sequentially arranged on the inner wall of the boiler shell from top to bottom. An evaporation section flat coil pipe is arranged on the inner side of the coil pipe water-cooled wall spiral coil pipe in the boiler shell; according to the device, the superheat section is arranged on the water cooling wall, the superheat degree of steam is improved through radiation heat o