The basic requirements of the waste heat recovery boiler body in the actual project
1 The waste heat recovery boiler is built-in and installed in the large flue, the flue gas passage of the device is well sealed, and the air leakage rate is zero.
2. The waste heat recovery boiler has a reasonable and advanced structure, which can adapt to the frequent load changes of the sintering machine and meet the requirements of rapid start-stop operation. It is also easy to operate, easy to maintain, and stable in performance, which can ensure long-term, reliable, efficient and economical operation of the waste heat boiler. In order to facilitate future maintenance and maintenance, the flue gas pipes of each evaporator module are provided with maintenance and observation manholes.
3 The waste heat recovery boiler can be used for variable load operation, and it can run stably for a long time under the condition that the load is not less than 30%.
4 The annual running time of waste heat recovery boiler equipment shall not be less than 8300 hours. The overall service life of the waste heat recovery boiler body is not less than 20 years.
5 The pressure bearing capacity of the waste heat recovery boiler body flue: the design pressure of the flue gas side is -20KPa. Under the design pressure, there will be no permanent deformation between the inner and outer guard plates and supports of the body flue.
6 The waste heat recovery boiler is equipped with heat preservation measures to reduce the heat loss of the boiler.
7. The steam drums are all horizontal and arranged on the upper platform of the large flue. There are steam-water separators inside to ensure the quality of steam supply.
8 The body of the waste heat recovery boiler is delivered in modular form, reducing the workload of on-site assembly and welding. All corresponding parts are manufactured to standard specifications. The manufacturing process of equipment components is accurate, and has good craftsmanship and smoothness, suitable tolerance fit, can be easily disassembled, replaced and repaired, and has convenient lifting or handling measures (such as lifting lugs, etc.) during installation or maintenance. During the manufacturing process of each module, corresponding measures need to be taken to ensure that each component will not be locally deformed due to welding heat. The manufacturing of each module requires a flat surface, and corresponding measures are taken to ensure no deformation during placement and transportation.
9 The waste heat recovery system is equipped with deaerator, steam drum, deaerator evaporator, economizer, boiler evaporator and superheater.
10 Party B shall solve the wear-resisting problem of the heat exchange surface in the high-dust environment through reasonable design.
11 Party B shall ensure uniform air flow through reasonable design, and the flue gas velocity shall be ≤7m/s.
12 To ensure that there will be no ash blockage between the heat exchange tubes under the condition of low flow rate, the heat exchange effect of the device should be guaranteed.
13 A sufficient number of full-open safety valves shall be set for the waste heat recovery boiler.
During the structural design of the waste heat recovery device, attention should be paid to:
(1) The steam drum, header and heating surface of the waste heat recovery device shall adopt welded structure, and the manhole and inspection hole shall be connected by flanges with fastening seals.
(2) All materials used in the waste heat recovery device comply with the corresponding national standards and usage requirements. The materials used for pressure-bearing parts and main load-bearing parts (such as large slab beams, suspenders, etc.) should meet the corresponding material standards, and the material properties should meet the requirements of the service conditions. Materials (including pipes, welding rods, etc.) for manufacturing important pressure-bearing parts and main load-bearing parts have chemical composition, mechanical properties, allowable temperature and non-destructive inspection certificates, and metallographic inspection results if necessary.
(3) The data of the brittle transition temperature shall be provided for the steel plate used to manufacture the steam drum. Each steel plate and weld seam used in the manufacture of the boiler drum shall be inspected and 100% non-destructive testing shall be carried out, and a qualification certificate shall be provided. The longitudinal and circumferential weld seams of the drum drum shall be ground flat, And by 100% non-destructive testing qualified.
(4) The welds of each heating surface pipe of the waste heat recovery device are subject to 100% non-destructive inspection, and there is a certificate of inspection. Strict inspection is carried out before leaving the factory, and there is no foreign matter and welding slag left in the pipe and header. All heat exchange base tubes are made of GB5310-2008 20G high-pressure boiler tubes, and the wall thickness of the tubes is ≥3.5mm.
(5) The heating surfaces of the waste heat recovery device should be easy for maintenance personnel to approach, and there should be enough space between each other, and the space for personnel to pass around the medium-pressure steam drum should be considered.
(6) The operation of the waste heat recovery device should be able to adapt to the influence of changes in exhaust gas parameters.
(7) Equipped with a steam drum operating platform.