At present, tubular furnace is widely used at home and abroad, so how to choose the type of tubular furnace? In fact, the type of tubular furnace should be selected according to the size of heat load, the nature of heated medium, operation cycle and other process operation requirements, the principle of convenient installation and maintenance and less investment, and in combination with the site conditions and the hot spots of waste heat recovery system. Generally, the selection of tubular furnace type should meet the following requirements:

1. When the design load is less than 1MW, the pure radiation type tubular furnace should be selected, and the pure radiation type cylindrical furnace should be preferred. This is not necessary when the tubular furnace group shares a combined waste heat recovery system and the reformer heating furnace is required.

2. When the design load is 1 ~ 30MW, the radiation convection cylindrical furnace shall be preferred. When the design load is greater than 30MW, the cylindrical furnace, box furnace, vertical furnace or other furnace types with intermediate tubes in the furnace shall be selected through technical and economic comparison.

3. If the heated medium has heavy weight, high gasification rate, easy coking or special process requirements, the horizontal tubular vertical furnace should be selected. If the heated medium is easy to drag out crystals or contains solid substances, the spiral tube cylindrical furnace should be selected.

4. The furnace tube is expensive. When it is required to provide the surface utilization rate of the furnace tube, or to reduce the heating area and shorten the process length to reduce the pressure drop, the furnace type with single row of tubes and double-sided radiation should be selected.

5. When the heated medium takes the gas phase as the continuous phase, the volume flow is large, and the pressure drop is required to be small, it is suitable to select the box furnace with the header riser, U-shaped, inverted U-shaped or Π coil structure. When the load is small, the riser cylindrical furnace with the coil connected to the header can also be used.

6. When the heated medium has chemical reaction, the temperature field in the furnace should adapt to the chemical reaction process in the drinking tube, and the box furnace with single row of tubes and double-sided radiation should be selected.