Performance Testing of Valves Under Cold and Hot Conditions (Part One)
Dec 03, 2024
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In industries such as petroleum, chemical engineering, and nuclear power, valves typically operate under high-temperature and high-pressure conditions. Simulating operating conditions that replicate real-world scenarios to evaluate valve performance is essential for ensuring product quality. This paper presents a test system developed to evaluate valve performance under cold and hot conditions, detailing its principles of operation, testing methods, and evaluation criteria. It seeks to serve as a reference for the development of testing equipment and technologies for valves operating under these conditions.
1. Introduction
Valves are critical components for controlling pipeline flow, ensuring safety, and regulating system operations. They play a pivotal role in industrial production, process control, and other key applications. Their functionality, performance, and reliability are crucial to the overall performance and stability of systems. Recent advancements in industries such as petroleum, chemical engineering, power generation, and metallurgy have led to more complex valve operating conditions and stricter performance requirements. Consequently, research on valve safety and reliability has gained increased importance.
In sectors such as nuclear power and petrochemicals, valves typically operate under high-temperature and high-pressure conditions. Initial testing and calibration are essential to ensure proper valve functionality during operation and compliance with standards and specifications. Valve testing conditions are categorized as hot or cold based on the test temperature. Tests performed at temperatures above 120°C are typically classified as hot tests, while those conducted at ambient temperatures are referred to as cold tests. Chen Jianbo from Dalian University of Technology conducted hot and cold tests on a nuclear-grade ball valve to assess its reliability and ensure compliance with nuclear performance standards. Similarly, Fu Minghai and his team at the Shanghai Special Equipment Supervision and Inspection Technology Research Institute conducted hot and cold tests to verify the performance of the ACP1000 main steam safety valve for nuclear islands.
In conclusion, hot and cold valve tests are vital in sectors such as nuclear power and chemical engineering to ensure reliability and assess performance under operational conditions. However, research on hot and cold valve testing methods in China is still limited. This article provides engineering insights into the design and operation of hot and cold valve test benches and testing methodologies.
In sectors such as nuclear power and petrochemicals, valves typically operate under high-temperature and high-pressure conditions. Initial testing and calibration are essential to ensure proper valve functionality during operation and compliance with standards and specifications. Valve testing conditions are categorized as hot or cold based on the test temperature. Tests performed at temperatures above 120°C are typically classified as hot tests, while those conducted at ambient temperatures are referred to as cold tests. Chen Jianbo from Dalian University of Technology conducted hot and cold tests on a nuclear-grade ball valve to assess its reliability and ensure compliance with nuclear performance standards. Similarly, Fu Minghai and his team at the Shanghai Special Equipment Supervision and Inspection Technology Research Institute conducted hot and cold tests to verify the performance of the ACP1000 main steam safety valve for nuclear islands.
In conclusion, hot and cold valve tests are vital in sectors such as nuclear power and chemical engineering to ensure reliability and assess performance under operational conditions. However, research on hot and cold valve testing methods in China is still limited. This article provides engineering insights into the design and operation of hot and cold valve test benches and testing methodologies.
2. Cold and Hot Cycle Test System
2.1 Test Device
The valve hot test system supports functional testing for both cold and hot cycles simultaneously (Figure 1). The system features a closed-cycle design and consists of a high-temperature water tank, circulating water pump, booster pump, test valve, temperature and pressure sensors, and an electrical control system. The high-temperature water tank, typically filled with deionized water, heats and stores the test medium and is equipped with electric heating elements and sensors to monitor temperature, pressure, and liquid level. The circulating and booster pumps pressurize and deliver the heated test medium to the test valve, maintaining the temperature and pressure conditions necessary to replicate real-world operating scenarios. Integrated with the electrical control system, temperature and pressure sensors monitor system conditions and regulate component operations, including water pumps.
The main operating principles of the test system are as follows:
Before testing, the valve is installed in the system pipeline and adjusted to the required opening position. The test medium is introduced into the system, and the pressure is gradually increased to the specified test pressure. This process ensures that the valve connection remains sealed under test conditions. Next, electric heating elements in the high-temperature, high-pressure water tank heat the test medium to the required temperature. Simultaneously, the circulating water pump is activated to transfer the heated water to the test valve for preheating. The circulation continues until the water tank temperature meets the specified test conditions, and the valve temperature reaches the required level. Once the valve surface temperature reaches the test temperature, the booster pump is activated to pressurize the water in the pipeline. The pressurized, high-temperature water then flows to the test valve, initiating the hot test. After completing the valve test, all electric heaters are turned off. The medium circulation pump continues to operate, and the cooler is activated to cool and depressurize the loop system. The cooling system controls the rate of temperature reduction in the pipeline and test valve body to minimize thermal stress during cooling. Once the medium's temperature and pressure in the pipeline stabilize at normal levels, the circulation pump is turned off, the test valve is removed, and the pipeline is cleaned for the next test.
1. High temperature and high-pressure water tank 2. Electric heating wire 3. Liquid level controller 4. Temperature and pressure sensor 5. Globe valve 6. Circulating water pump 7. Flow meter 8. Booster water pump 9. Globe valve 10. Temperature and pressure sensor 11. Tested valve 12. Temperature and pressure sensor 13. Globe valve 14. Check valve
Figure 1 Hot test system for valves
The main operating principles of the test system are as follows:
Before testing, the valve is installed in the system pipeline and adjusted to the required opening position. The test medium is introduced into the system, and the pressure is gradually increased to the specified test pressure. This process ensures that the valve connection remains sealed under test conditions. Next, electric heating elements in the high-temperature, high-pressure water tank heat the test medium to the required temperature. Simultaneously, the circulating water pump is activated to transfer the heated water to the test valve for preheating. The circulation continues until the water tank temperature meets the specified test conditions, and the valve temperature reaches the required level. Once the valve surface temperature reaches the test temperature, the booster pump is activated to pressurize the water in the pipeline. The pressurized, high-temperature water then flows to the test valve, initiating the hot test. After completing the valve test, all electric heaters are turned off. The medium circulation pump continues to operate, and the cooler is activated to cool and depressurize the loop system. The cooling system controls the rate of temperature reduction in the pipeline and test valve body to minimize thermal stress during cooling. Once the medium's temperature and pressure in the pipeline stabilize at normal levels, the circulation pump is turned off, the test valve is removed, and the pipeline is cleaned for the next test.
1. High temperature and high-pressure water tank 2. Electric heating wire 3. Liquid level controller 4. Temperature and pressure sensor 5. Globe valve 6. Circulating water pump 7. Flow meter 8. Booster water pump 9. Globe valve 10. Temperature and pressure sensor 11. Tested valve 12. Temperature and pressure sensor 13. Globe valve 14. Check valve
Figure 1 Hot test system for valves
2.2 Arrangement of Measurement Points
In this test system, the arrangement and selection of measurement points are essential. The primary measurement parameters are temperature, pressure, liquid level, and flow. Temperature, pressure, and liquid level sensors are located in the water tank. The temperature and pressure sensors continuously monitor the conditions in the water tank to ensure compliance with test requirements. The liquid level sensor monitors the water level in the tank to prevent risks from excessive or insufficient levels. The flow sensor is located in the pipeline to monitor the system's flow rate. Temperature and pressure sensors are installed upstream and downstream of the valve. These sensors verify whether conditions before and after the valve meet the test requirements. The arrangement of each primary measurement point is shown in Figure 1.
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