Common Problems and Inspection Requirements During Boiler Periodic Inspection

Introduction

As high-pressure equipment, boiler operation involves complex working conditions such as high temperature, high pressure and combustion, so regular inspection is very important. This is not only the requirement of industry regulations, but also an important measure to ensure safety, improve efficiency and prolong equipment life.

Regular inspection can timely discover the hidden dangers such as aging, corrosion, cracks, leakage, carbon deposition, scaling, etc. of boiler pressure components, and inspect key components such as combustion system, safety valve and water level gauge to prevent abnormal operation. Through inspection and maintenance, safety accidents can be effectively avoided, combustion efficiency can be optimized, energy consumption and emissions can be reduced, and long-term stable operation of boilers can be ensured. Enterprises should strictly implement the inspection plan and adopt advanced inspection technology to ensure that the boiler is always in the best state and ensure production safety and economic benefits.

1. The importance of boiler regular inspection.

Boiler has been working in high temperature and high pressure environment for a long time, and all components are facing severe tests. Wear, corrosion, cracks, leakage and deformation may occur at any time. If these problems are not found in time, they will accumulate over time and may eventually lead to serious safety accidents. For example, when the boiler is working, the problems of cracks and leakage are often difficult to be directly observed due to the erosion of high-temperature flame, and the slight deformation of the pressure parts may escape the routine inspection because of its concealment.

In addition, the original defects that may exist in the process of boiler design, manufacture and installation, if not properly inspected and corrected, will intensify with the increase of service time and become a safety hazard. Before the new boiler is put into use, although it will go through a series of registration and inspection procedures, these inspections may not fully reveal all potential problems, especially some hidden problems. At the same time, under the long-term high temperature and high pressure operation conditions, the steel of boiler heating surface may have interlayer defects, which will not only reduce the heat conduction effect, but also lead to the deformation of steel and bury potential safety hazards. Therefore, regular inspection work is very important for finding these problems, which can help us to take timely measures to repair or replace damaged parts, thus ensuring the safe operation of the boiler, avoiding possible accidents and protecting the safety of personnel and equipment.

2. Analysis of specific contents in boiler inspection

Boiler inspection is a complex and meticulous work, involving many aspects of boiler internal structure. The inspection work should start from the overall operation state of the boiler, including internal and external inspection, to ensure the performance of the boiler under normal working conditions. In addition, the water pressure test is a key step to test the pressure bearing capacity of the boiler, which can help to understand the pressure condition of the boiler in actual work.

The external inspection of the boiler is a routine inspection content, including the inspection of the external structure and components of the boiler to ensure that there is no obvious damage or defect. At the same time, the quality inspection of the valve is also very important, because the valve is an important part of the boiler system and is directly related to the safe operation of the boiler. In addition, the inspection of other safety accessories is also a key factor to ensure the safe operation of the boiler.

When turning to boiler internal inspection, specific steps need to be taken. First, close the valve and stop the boiler operation, so as to safely enter the interior for inspection. It is important to inspect the pressure-bearing parts inside the boiler. These parts are under great pressure during the operation of the boiler, so it is necessary to carefully analyze whether these pressure-bearing parts have quality problems, such as wear, cracks and corrosion. Through the detailed inspection of these internal components, combined with the overall operation effect of the boiler, the working conditions of other internal components of the boiler are judged.

In view of the complexity of the inspection task and the corresponding risks and challenges, appropriate protective measures must be taken. Inspection personnel are required to strictly follow the established procedures and standards when performing inspection to ensure the safety and effectiveness of inspection work.

3 Boiler Inspection Common Problems and Inspection Requirements

3.1 Common Problems and Inspection Requirements of Drum Inspection

In boiler inspection, boiler drum inspection is regarded as a key link, and problems such as cracks and cracks appear in the boiler drum due to the constant change of external environment and conditions. When performing boiler inspection tasks, it is necessary to carefully inspect all parts of the boiler drum, especially the welding position, where cracks often appear, which is the most difficult to be detected.

In addition, the corrosion problem generally exists in the running process of boiler drum, which requires the responsible person to carefully monitor the distribution of water vapor inside the boiler drum and check the head parts on both sides of the boiler. In order to ensure the normal operation and use of the boiler drum, the parts prone to scale are continuously inspected, and the water flow path of the boiler drum is emphatically inspected in detail, so as to fully understand the working effect of each position of the boiler drum and its actual use, and strictly abide by the regular inspection standards of the boiler drum, so as to ensure that all quality problems of the boiler drum are properly handled in daily operation.

3.2 Common Problems and Inspection Requirements of Water Wall

The water wall is not only a key part of the boiler, but also the most vulnerable part. Many quality problems such as deformation, swelling, roughness and cracks often occur in the water wall of boiler in use. For the deformation of water wall caused by thermal influence, the main performance is that the water wall bears a high thermal load. For the areas where the boiler water-cooled wall is easily affected by heat load, regular inspection should be carried out and the problem of thermal corrosion of the water-cooled wall should be solved in time, so as to ensure that the deformation fault of the water-cooled wall can be properly handled when it is heated.

The water circulation of boiler water wall is blocked, which is the main factor leading to the problem of bulging and heaving. If the water circulation on the surface of boiler water wall is unstable, its bearing and heat-bearing capacity will be obviously weakened, which will lead to the problem of bulging and heaving on the surface of boiler water wall, and the boiler water wall will lose its original performance. Cracks in water wall are also a common problem in the inspection process, and the probability of cracks in high heat-bearing parts and slag discharge pipes is high. Therefore, when inspecting the boiler water wall, we should carry out targeted inspection for the above problems to ensure the effectiveness of the inspection work and take preventive measures in advance for various possible problems.

3.3 Common Problems and Inspection Requirements of Desuperheater

Corrosion and oxidation are common problems in the detection of desuperheater, and their existence will directly affect the overall operation effect of boiler, so the detection of desuperheater can not be ignored.

At present, nondestructive testing method is widely used in the detection of desuperheater, which can be used to detect different parts of desuperheater, such as the parts of desuperheater, the hardness and thickness of desuperheater, and also to check the welding cracks of cylinder head. The welding cracks of desuperheater mainly appear in the bearing, pipe seat, header and lifting lug of desuperheater, and these parts should be inspected again to confirm whether there are cracks. Staff can conduct regular inspection of boiler desuperheater by sampling and core pulling, and carry out targeted inspection according to the length of boiler operation time. For boilers running for more than 50,000 hours, the water pressure test should be adopted to check the free expansion of the cylinder. For boilers that run for more than 100,000 hours, ultrasonic flaw detection should be adopted to carry out all-round inspection, such as cylinder, fillet weld and main weld surface. In addition, corrosion and cracks will occur in the desuperheater and at the tube plate, and regular spot checks can be conducted. Once the above problems are detected, effective measures should be taken to remedy them immediately and stop the loss in time to ensure the normal operation of the boiler.

3.4 Common Problems and Inspection Requirements of Economizer, Superheater and Reheater

Economizer, superheater and reheater are the main components of the boiler. After a long period of operation, economizer, superheater and reheater will show different degrees of wear and tear, which is also the main goal of regular inspection. If it is found that the economizer, superheater and reheater have wear problems, the periodic inspection results should be comprehensively considered and evaluated, and appropriate and effective treatment measures should be taken according to the wear severity of the economizer, superheater and reheater. In addition, the soot blowing pipe, top pipe and smoke outlet of economizer, superheater and reheater are also prone to wear problems. If these three parts are in a state of wear for a long time and are not solved in time, the boiler economizer, superheater and reheater pipe groups will have serious deformation problems and need to be inspected emphatically. Because the structure and performance of boiler economizer, superheater and reheater are different, the operation process and inspection mode should be adjusted appropriately according to their differences in structure and performance during periodic inspection to improve the periodic inspection efficiency of boiler economizer, superheater and reheater.

4 Optimization Measures for Periodic Inspection of Boilers

In order to ensure the comprehensive coverage of boiler periodic inspection and the concrete effect of fault treatment, the routine inspection contents should be optimized from multiple angles, so as to reduce the complexity of periodic inspection to a certain extent, and ensure that the sealing of boiler and the quality of overall construction can be fully protected and safely protected.

For boiler inspection, it is necessary not only to carry out internal and external inspection, but also to carry out effective water pressure test according to the actual working conditions of the boiler. When regularly checking the periphery of the boiler, water leakage should be checked in time according to the pressure and temperature changes of the boiler. In the specific operation process, the operation valve of the boiler must be opened, so that the functionality and flexibility of the safety accessories of the boiler can be strictly checked under the condition of boiler operation, and the quality and stability of the external parts and basic components of the boiler can be ensured. During the operation and use of the boiler, the main parts prone to failure are concentrated in the drum, water wall, economizer, superheater, reheater and desuperheater. During the regular inspection of the inside of the boiler, it is necessary to ensure that the boiler stops working completely, and carry out specific safety review on the structure and key parts of the boiler to further understand the specific situation of the pressure-bearing parts inside the boiler, and then take effective measures to deal with possible safety problems based on this information.

Conclusion

In order to ensure the smooth and effective periodic inspection of boilers, the mode of periodic inspection should be determined based on the structure of boilers and their actual operating conditions, and the contents and basic items of periodic inspection of boilers should be optimized and adjusted as necessary. Organize a special team to carry out regular inspection of boilers, and prevent and control potential safety hazards that may occur during inspection, so as to ensure that the quality of regular inspection of boilers and actual management measures reach a higher standard. In view of all kinds of problems encountered in periodic inspection of boilers, relevant measures must be carefully optimized and adjusted from the scheduled inspection items and actual operation requirements of boilers to ensure that the fault handling efficiency of various parts of boilers is significantly improved.