The invention discloses a three-return-
stroke powder heat conduction oil boiler. The three-return-
stroke powder heat conduction oil boiler comprises a circulating
oil pump, a
hearth, a
burnout chamber, a
convection tube bundle,
tail heat exchange equipment, a
combustor, a
slag falling device, a lower header and an upper header, wherein the lower header is arranged at the bottom of a boiler body; the upper header is arranged at the top of the boiler body; the
combustor is arranged at the front part, the top, the bottom or the side part of the
hearth of the boiler; the boiler body has a full-film type water-cooled wall structure, and four main downcomers are arranged at four corners; the
convection tube bundle is arranged in a
convection tube bundle
flue, the convection tube bundle
flue is longitudinally arranged, and the height of the convection tube bundle
flue is equal to that of the
hearth; the upper and lower ends of the convection tube bundle, the main downcomers and a film type water-cooled wall are communicated with the upper header and the lower header respectively; the
burnout chamber and the hearth are longitudinally arranged abreast in a back-to-back way, and the height of the
burnout chamber is equal to that of the hearth; the hearth, the burnout chamber, the convection tube bundle flue and the
tail heat exchange equipment are sequentially conducted in series; two-stage
combustion-supporting and denitration secondary air is distributed in the hearth. The three-return-
stroke powder heat conduction oil boiler has the characteristics of long
flue gas flow, complete fuel
combustion and
high heat exchange efficiency.