These large-capacity pressurized biomass hot water boilers feature a compact structure for simple transport and installation. As shop-assembled longitudinal double-drum water-tube boilers with natural circulation, SZL series is shipped in two modules: upper heating surface and lower combustion section. The furnace uses full surrounding water-wall tubes linked to the upper drum, and dense convection tube banks sit between upper and lower drums. Its roller-supported lightweight grate adopts zoned air supply to enable flexible combustion control.
Features
The SZL series is a coal-fired natural-circulation longitudinal double-drum water-tube hot water boiler. It is factory-assembled and delivered in two modules: upper heating surface and lower combustion assembly.
The furnace chamber is surrounded by water-wall tubes connecting to the upper drum, with dense convection tube banks fitted between the upper and lower drums at the rear. The grate adopts large lightweight grate bars with midpoint roller support and zoned air supply for flexible adjustment. Advanced combustion arch technology is applied inside the furnace.
Boiler highlights: sufficient heat output, high thermal efficiency and 10–20% overload capability. Its thermal efficiency is 3–8% higher than national standards, with outstanding dust removal performance. As a widely adopted next-generation model, it features low investment, compact elegant structure, quick installation and safe & stable operation.
Technical Parameters
| Item | Unit | SZL1.4-0.7/95/70-MA | SZL2.8-0.7/95/70-MA | SZL4.2-1.0/115/70-MA | SZL7.0-1.0/115/70-MA |
| Rated Power | MW | 1.4 | 2.8 | 4.2 | 7.0 |
| Working Pressure | MPa | 0.7 | 0.7 | 1.0 | 1.0 |
| Outlet / Return Water Temp. | ℃ | 95/70 | 95/70 | 115/70 | 115/70 |
| Circulating Water Flow | t/h | 48 | 96 | 80 | 133.3 |
| Total Heating Surface Area | m² | 84.84 | 137.24 | 243.95 | 408 |
| Grate Area | m² | 3 | 4.74 | 7.78 | 11.72 |
| Applicable Coal Type | – | A II | |||
| Combustion Mode | – | Forced | |||
| Thermal Efficiency | % | 79.18 | 79.1 | 81.05 | 78.7 |
| Coal Consumption | kg/h | 359.64 | 720.36 | 1035 | 1800 |
| Transport Weight | t | 25 | 28 | 62.983, shipped in 2 main assemblies | 88, shipped in 2 main assemblies |
| Overall Installation Dimension (L×W×H) | m | 6.8×4.3×4.0 | 7.8×4.7×4.0 | 8.0×3.6×6.15 | 9.8×5.2×6.0 |