Non-metallic expansion joints are widely used in power plants, mainly because their unique performance advantages can meet the requirements of complex working conditions in power plants. Here are the specific reasons why non-metallic expansion joints are used more in power plants:
1. Excellent corrosion resistance
Power plant dielectric characteristics: The flue gas of power plants contains corrosive gases such as SO₂, NO₂, HCl, and the high humidity environment after wet desulfurization, which is easy to cause corrosion to metal materials.
Advantages of non-metallic materials: Non-metallic expansion joints usually use fluororubber, polytetrafluoroethylene (PTFE), glass fiber and other corrosion-resistant materials, which can effectively resist chemical corrosion and prolong the service life.
2. Good high temperature resistance
High temperature flue gas environment: The exhaust temperature of power plant boiler is high, especially before desulfurization, it can reach above 200℃ or even higher.
Non-metallic material adaptability: The non-metallic expansion joint adopts high temperature resistant materials (such as silica gel, glass fiber coating, etc.), which can work stably for a long time in high temperature environment.
3. Excellent compensation ability
Thermal displacement requirements: The pipeline system of power plant produces large thermal expansion and contraction displacement due to temperature change, and the non-metallic expansion joint has large axial, transverse and angular compensation ability.
Flexible design: The non-metallic expansion joint has a soft structure, which can absorb multi-directional displacement and vibration and reduce the stress influence on the pipeline system.
4. Good sealing performance
Flue gas leakage problem: The flue gas of power plants contains harmful substances, and the leakage will cause harm to the environment and equipment.
Advantages of non-metallic expansion joints: Non-metallic materials have good sealing performance, can effectively prevent smoke leakage and meet environmental protection requirements.
5. Vibration resistance and shock absorption performance
Power plant vibration source: Power plant equipment (e.g. fans, pumps, boilers) will generate vibration when it is operated, causing impact on the pipeline system.
Non-metallic expansion joint characteristics: Non-metallic materials have good elasticity and damping characteristics, can absorb vibration energy and reduce the impact on pipeline system.
6. Lightweight design
Easy installation and maintenance: The non-metallic expansion joint is lighter in weight, easy to install and replace, reducing construction difficulty and maintenance cost.
Low requirements for support structure: The lightweight design reduces the requirements for the pipeline support structure and saves material and construction costs.
&nb sp; 7. Economy
Cost advantage: Compared to metal expansion joints, non-metallic expansion joints have advantages in material and manufacturing cost, especially in corrosive environments, with longer service life and lower comprehensive cost.
Low maintenance costs: Non-metallic expansion joints are resistant to corrosion and wear, reducing the frequency of maintenance and replacement and reducing long-term operating costs.
8. Adapt to complex working conditions
Multi-condition requirements: The pipeline system of power plant may face a variety of complex working conditions such as high temperature, corrosion and vibration at the same time, and non-metallic expansion joints can comprehensively meet these needs.
Customized design: Non-metallic expansion joints can be customized and designed according to specific working conditions, such as adding heat insulation layer, anti-corrosion layer, etc., to further improve performance.
9. Environmental Protection and Safety
Environmental protection requirements: Non-metallic expansion joints can effectively prevent smoke leakage and meet strict environmental protection emission standards.
Safety: Non-metallic materials are not easy to generate sparks, suitable for flammable and explosive environments, and improve the safety of power plant operation.
10. Typical Case Application
Desulfurization System (FGD): Non-metallic expansion joints are widely used in the inlet and outlet flue of absorption tower of wet desulfurization system, which is resistant to corrosive media and high temperature and high humidity environment.
Boiler flue: For the connection between the boiler and the chimney to compensate for thermal displacement and absorb vibration.
Fan inlet and outlet: Used for the connection of fan and pipeline to reduce vibration transmission and noise.
Summary
Non-metallic expansion joints are widely used in power plants, mainly because of their significant advantages in corrosion resistance, high temperature resistance, compensation ability, sealing performance, vibration resistance, lightweight design, economy and adaptation to complex working conditions. These characteristics allow it to meet the demanding operating environment requirements of power plants while reducing maintenance costs and improving system reliability and safety.