The waste heat boiler of industrial submerged arc furnace silicon is composed of a superheater section, an evaporator section, an economizer section, and its auxiliary equipment and accessories. The waste heat boiler of an industrial silicon smelting furnace uses the tail gas discharged from the industrial silicon smelting furnace to lead into the waste heat boiler for heat exchange, generating 1.0MPa-2.5MPa superheated steam, so as to save fuel and achieve the purpose of economy and energy conservation.
The heating surface of the waste heat boiler is generally composed of a superheater section, an evaporator section, and an economizer section. According to the heat balance calculation of the waste heat boiler, to achieve the maximum steam output of a single waste heat boiler, the waste heat boiler must be equipped with an economizer section to further absorb the medium and low-level energy of the exhaust with water. On the one hand, it can increase the feed water temperature, and increase the steam output of the waste heat boiler, and on the other hand, it can improve the effective utilization of the heating surface of the evaporator section.
The waste heat boiler of the submerged arc furnace silicon adopts a modular structure. Each waste heat boiler is composed of five parts, including the inlet smoke box, superheater section, evaporator section, economizer section, and outlet smoke box. The actual fabrication of the waste heat boiler in the factory needs to be segmented according to the transportation situation, so that the transportation can be divided into five parts, including the inlet smoke box, superheater section, evaporator section, economizer section, and outlet smoke box. The waste heat boiler can be assembled only after being transported to the construction site.
1. Inlet and Outlet Smoke Boxes:
The inlet and outlet smoke boxes of the waste heat boiler are welded by steel plates. Hanging plates are installed on the smoke boxes for lifting and installation. An inspection door is set on the cigarette box for the user to enter the cigarette box for maintenance.
2. Economizer Section:
The economizer section is mainly composed of the framework, coil unit, inlet and outlet headers, and accessories. The economizer is mainly used to further absorb the low-level energy of waste gas. On the one hand, it increases the feed water temperature and ensures the steam output of the waste heat boiler; on the other hand, it can increase the outlet gas temperature of the evaporator section and increase the effective utilization rate of the heating surface.
3. Evaporator Section:
The evaporator section is mainly composed of the framework, coil group, inlet and outlet headers, and their accessories, which are the main heat exchange sections of the waste heat boiler. After absorbing heat in this section, the working medium will have a phase change from the liquid phase to the vapor-liquid phase. After steam water separation, it can provide saturated steam to the superheater section.
4. Superheater Section:
The superheater section is mainly composed of the framework, coil group, inlet and outlet headers, and accessories, which are the main heat exchange sections of the waste heat boiler. The working medium absorbs heat in this section and generates superheated steam that meets the requirements of steam turbine power generation.
1. High-cost Performance
As this waste heat boiler of the submerged arc furnace silicon adopts needle tube heat exchange elements and a vertical modular layout structure, the overall investment costs of equipment, installation, and infrastructure are greatly reduced under the same heat exchange area, which provides users with large space in terms of equipment installation and layout.
As the needle rib of the needle tube is a cantilever structure, under the impact of airflow, the needle rib will vibrate, making it difficult for soot to accumulate. In addition, due to the strong turbulent flushing of flue gas, the needle tube heat exchanger has a strong ability of self dust removal.
3. Wear Resistance
The needle tube is arranged in sequence. The needle rib divides the space into several small areas, which has a flow-sharing effect on the airflow. Compared with the smooth tube and spiral fin tube arranged in a staggered arrangement, the wear life is 3 to 4 times higher under the same conditions.
4. Low Energy Consumption
Needle pitch, tube pitch, and arrangement form of needle-shaped tubes are important design parameters of waste heat boiler. Whether the boiler scours the tube bundle horizontally or longitudinally, all the needle-shaped extended surfaces are scoured by the transverse turbulence of flue gas. The airflow forms symmetrical steady vortices and backflow areas at the back of the cylinder of the needle rib, and the thermal boundary layer is constantly destroyed and reformed, so that the entire heat exchange boundary layer is thinner, the thermal resistance is reduced, and the heat transfer coefficient is increased.
5. Well Sealed
All butt welds are welded by argon arc welding, and the welding quality is greatly improved to that of manual welding.
6. Lightweight and Small Volume
Due to the vertical arrangement of the equipment, the reverse heat exchange between flue gas and water is realized, and the volume and weight are greatly reduced. The heat transfer area per unit length is large. The heat transfer area of the needle tube is 7-8 times that of the plain tube and 1-3 times that of the spiral-finned tube.