SZS series boiler is designed with longitudinal double drums and " D " type chamber structure. The furnace is on the right and convection tube bank is on the left. The body is fixed on the basement by middle and both end flexible supports and make the boiler expand horizontally sideways. Around the furnace is membrane wall. Furnace and tube bundle are totally separated by the membrane wall at the left side of the furnace. The back part of convection tube bank is sparse shift structure, front part is aligned structure. Smoke from furnace outlet enters re-burning chamber, convection tube bank area, and then from left front part enters spiral fin coil economizer and condenser, and finally is discharged to atmosphere through chimney.