The WNS low-nitrogen gas steam boiler is a horizontal internal-combustion, fast-loading steam boiler developed by AIX BOILER for applications requiring a stable and efficient steam supply. It adopts an advanced shell-type, three-pass wet-back structure, integrating the boiler body, burner, steam-water system, instruments, economizer and other key components into a compact overall design.

The core value of the WNS boiler lies in its combination of high efficiency, low nitrogen oxide emissions, compact structure, automatic operation and reliable safety protection. According to the boiler configuration, natural gas, light oil or heavy oil can be used as the design fuel, allowing the equipment to adapt to different industrial energy conditions.

During operation, fuel is injected through the burner and ignited by an electronic ignition system. The fuel burns inside the furnace under slight positive pressure. The high-temperature flue gas then passes through the second and third smoke-tube passes before entering the economizer for further heat exchange. This multi-pass heat-transfer process effectively utilizes the heat of the flue gas and reduces exhaust gas temperature, improving the overall thermal efficiency of the boiler.

The WNS series is available in different steam capacities, including models from approximately 1 t/h to 20 t/h, making it suitable for a wide range of industrial steam applications. The series can therefore be configured according to the customer's required steam capacity, working pressure and fuel type.

The WNS low-nitrogen gas steam boiler adopts a horizontal shell-type and three-pass wet-back structure,

 which provides a compact arrangement while improving heat-transfer performance. The first pass consists of the corrugated furnace and rear combustion chamber, while the second and third passes are formed by smoke tubes.

One of the key features of the boiler is its low-NOx combustion technology. The catalog specifies the use of FGR flue-gas recirculation technology to effectively reduce nitrogen oxide emissions, with NOx emissions designed to be below 30 mg/m³ under the stated operating conditions. This makes the boiler suitable for industrial projects with increasingly strict environmental requirements.

The boiler is also equipped with an economizer installed at the upper part of the boiler. According to the catalog, the economizer uses spiral finned tubes to increase the heat-transfer area and recover additional heat from the exhaust gas. The recovered heat can be utilized to improve boiler efficiency and reduce energy losses through the chimney.

For operation and maintenance, the boiler adopts a complete automatic control and safety protection system. It includes functions such as high- and low-water-level alarms, low-water-level interlocking protection, automatic ignition, automatic burner firing-rate adjustment and flameout protection. These functions reduce the need for manual intervention while improving the safety and stability of boiler operation.

The boiler body is also designed with a wet-back structure and integrated inspection/maintenance arrangements, while heat-insulation materials are used to reduce heat loss and improve thermal insulation performance. The overall structure is compact, with relatively convenient transportation, installation and maintenance.

The operation of the WNS low-nitrogen gas steam boiler follows an automatic control sequence designed to ensure safe and stable combustion and steam production.

Before ignition, the boiler's safety protection and control system should be checked to ensure that the relevant instruments, burner, feedwater system and interlocking functions are operating normally. The water level should be maintained within the specified operating range, and the fuel supply system should be confirmed to be ready for operation.

After the boiler receives the ignition command, the burner performs the required pre-purge and ignition sequence. The fuel is then injected into the furnace and ignited by the electronic ignition system. The combustion process is continuously monitored, and the burner automatically adjusts its firing rate according to the steam demand.

During normal operation, the feedwater system maintains the required boiler water level, while pressure and water-level instruments continuously monitor the operating condition of the boiler. If the water level falls to an unsafe level, the low-water-level protection and interlocking system can intervene to protect the boiler.

The combustion system is also designed with automatic flameout protection. If abnormal combustion or flame failure occurs, the control system can shut down the fuel supply to prevent unsafe operating conditions.

After combustion, the high-temperature flue gas passes through the three-pass heating structure. After transferring heat to the boiler water through the furnace and smoke tubes, the flue gas enters the economizer for additional heat recovery before being discharged through the chimney.

For low-emission operation, the FGR system recirculates part of the flue gas to the combustion process, reducing combustion temperature and consequently suppressing NOx formation. This technology enables the WNS boiler to achieve significantly lower nitrogen oxide emissions while maintaining stable combustion.

The WNS low-nitrogen gas steam boiler is particularly suitable for industrial facilities requiring a stable, clean and automatically controlled steam source.

Its compact horizontal structure and fast-loading design make it suitable for projects where installation space and construction time need to be controlled. The boiler can be used in different industrial applications where steam is required for production processes, heating, drying, sterilization and other thermal-energy requirements.

The availability of multiple steam-capacity models allows users to select an appropriate boiler according to actual steam demand. For example, the WNS series in the AIX catalog covers models from 1 t/h, 2 t/h, 3 t/h, 4 t/h, 6 t/h, 8 t/h, 10 t/h, 12 t/h, 15 t/h to 20 t/h, providing flexibility for different production scales.

Another important advantage is its fuel flexibility. Depending on the selected configuration, the boiler can be designed for natural gas, light oil or heavy oil, allowing customers to select the most suitable fuel according to local fuel availability and operating costs.

From an energy-efficiency perspective, the three-pass heat-transfer structure combined with the economizer allows more heat to be recovered from the combustion gases before they are discharged. Together with automatic combustion control, this helps reduce unnecessary fuel consumption during operation.

For projects with strict environmental requirements, the low-NOx configuration provides additional value. The combination of the low-nitrogen burner and FGR technology helps control NOx emissions while maintaining reliable boiler operation.

Overall, the WNS low-nitrogen gas steam boiler provides a practical combination of high-efficiency heat transfer, low-NOx combustion, automatic control, safety protection and flexible fuel selection, making it a suitable steam-generation solution for modern industrial applications.