The ethylene cracking furnace is divided into a convection section and a radiation section. Generally speaking, the function of the convection section is to recover the waste heat of the flue gas, which is used to preheat and vaporize the raw oil, and superheat the raw oil and dilution steam to the cross temperature of the material, and the remaining Heat is used to superheat ultra-high pressure steam and preheat boiler feed water. In the process of preheating and vaporizing raw materials, dilution steam is injected to reduce the vaporization temperature of raw oil and prevent raw oil from coking during the vaporization process. Each group of disks in the convection section of the cracking furnace The tube is mainly composed of heat exchange furnace tubes (smooth tubes or finned tubes) welded by return elbows. The end tube sheets and the middle tube sheets support the furnace tubes, and the inlet and outlet of some coils are collected together through the header. A group of coils are a ssembled around the furnace wall to form a module
Heating furnace convection section module
Designing and manufacturing a complete set of heating furnaces, converting furnace drawings and modular prefabrication in the factory, and pre-assembling the furnace body's segmented steel structure, reducing the amount of on-site installation engineering, which can significantly shorten the engineering cycle and ensure engineering quality.
Modular manufacturing of heating furnaces
In the convection section of the heating furnace, the manufacture of the box module is generally completed in the factory, including the steel structure of the box, the installation of the tube sheet, the construction of the lining and insulation nails, the furnace pipe, and the welding of the sharp bend pipe. It is generally divided into one or more box modules, and the hoisting of the modules is completed on site.
Heating furnace coil welding
When designing and manufacturing a complete set of heating furnaces, the key link of manufacturing quality control is the welding of coils. Welding is carried out in strict accordance with the welding process, and the quality inspection is strictly controlled to ensure that each weld meets the requirements. The convection section components are mainly used for preheating raw materials, steam for generating and superheating reaction, and recovering waste heat in flue gas.
The layout of the convection section used in different process schemes is slightly different, mainly including the raw material/steam mixed superheating section, the steam superheating section, the steam generation section, and the combustion air preheating section.