Two-range radiant section furnace tube used for ethylene cracking furnace

The invention discloses a two-range radiant section furnace tube used for an ethylene cracking furnace. Every two first-range furnace tubes are connected by an arced first-stage collection tube. The upper two tube orifices of the first-stage collection tube are connected to two first-range furnace tubes respectively. Two first-stage collection tubes are connected to an arced second-stage collection tube, the upper two tube orifices of which are connected to the lower tube orifices of the first-stage collection tubes respectively. The lower tube orifice of the second-stage collection tube is connected to a bent tube, the other end of which is connected to a second-range furnace tube. The two-range radiant section furnace tube provided by the invention can eliminate the additional force generated by deformation of a furnace tube bottom connecting piece to a radiation furnace tube, thus avoiding bending deformation of the radiation furnace tube, prolonging the operation cycle of a cracking furnace, and extending the service life of furnace tubes. At the same time, the flow rate fluctuation of reaction materials in the tube is small, no flow retention area appears, and the residence time of materials in the tube is reduced. The two-range radiant section furnace tube provided by the invention is in favor of hydrocarbon cracking reaction, and improves the yield of objective products.