A waste incinerator, in a vertical structure and including from the top down: a drying section, a destructive distillation section, a reduction section, and a combustion section. The combustion section includes: two layers of grate bars, a first combustion layer, a second combustion layer, and a third combustion layer. The heat produced from the combustion in the combustion section is used to heat the carbide in the reduction section. The heated carbide reduces CO2 produced in the combustion into CO (coal gas). The coal gas ascends to the destructive distillation section through the ambient coal gas chamber to heat and destructively distillate the waste to produce the pyrogenic coal gas and the carbide. The carbide drops to the combustion section for combustion, and the pyrogenic coal gas and the coal gas are collected by the draft fan.