A heat system drain valve leakage measuring system and method

Abstract

This invention discloses a system and method for measuring the leakage of a steam trap in a thermal system. By installing a heat measurement unit on the drain pipe at the outlet of the steam trap, this unit includes a heat exchanger, a radiator, a circulating pump, and temperature measuring elements at the hot and cold ends of the heat exchanger. By calculating the heat exchanger's heat transfer capacity and applying the principle of heat balance, the leakage flow rate of the steam trap is calculated, thus achieving real-time measurement of the steam trap leakage. This invention has a clear principle, a simple system, strong operability, and facilitates dynamic monitoring of the unit, improving the unit's operating economy. It is an innovative technology applicable to all units with steam traps for energy saving and efficiency improvement.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thermal power generation, and relates to a steam trap leakage measuring system and method, in particular to a steam trap leakage measuring system and method for a thermal system. BACKGROUND

[0002] In a thermal power generating unit, a steam trap pipeline needs to be arranged on a heat pipeline to ensure safety in abnormal conditions, but the steam trap valve on the steam trap pipeline needs to maintain good tightness during normal operation of the unit to prevent leakage of steam or high-quality water. In actual operation, some steam trap valves may leak, resulting in increased cost of replacing the steam trap valve, loss of a large amount of energy, and decline in economy and safety performance of the unit.

[0003] In the prior art, whether the steam trap valve leaks is often determined by installing a temperature measuring point in the pipeline behind the steam trap valve or directly by manual field observation, but currently, technical personnel can only detect whether the steam trap valve leaks, and cannot detect the size of the leakage of the steam trap valve of the unit, so that the actual impact of the valve leakage on the economy and safety of the unit cannot be accurately evaluated. SUMMARY

[0004] The present application aims to solve the problem that the leakage of the steam trap valve cannot be detected, so that the safety and economy of the unit cannot be evaluated, and provides a steam trap leakage measuring system and method for a thermal system, so as to measure the leakage of the steam trap valve of the thermal system, and accurately evaluate the actual impact of the valve leakage on the economy of the unit.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The present application provides a steam trap leakage measuring system for a thermal system, which comprises a leakage detection unit arranged on a steam trap pipeline, the leakage detection unit being arranged at an output end of a steam trap valve and comprising a heat exchanger, a radiator, a circulating pump, a hot end inlet temperature measuring element, a hot end outlet temperature measuring element, a cold end inlet temperature measuring element and a cold end outlet temperature measuring element.

[0007] The hot end inlet of the heat exchanger is connected to the output end of the steam trap valve through the steam trap pipeline; the hot end inlet temperature measuring element is arranged on the steam trap pipeline between the hot end inlet of the heat exchanger and the output end of the steam trap valve, and the hot end outlet temperature measuring element is arranged on the steam trap pipeline at the hot end outlet of the heat exchanger.

[0008] The cold end outlet of the heat exchanger is connected to the radiator and the circulating pump in sequence, and the output end of the circulating pump is connected to the cold end inlet of the heat exchanger; the cold end outlet temperature measuring element is arranged between the cold end outlet of the heat exchanger and the inlet of the radiator, and the cold end inlet temperature measuring element is arranged between the circulating pump and the cold end inlet of the heat exchanger.

[0009] Preferably, the circulating pump is a constant-speed circulating pump.

[0010] Preferably, a method for measuring the leakage amount of a drain valve using the system comprises the following steps:

[0011] calculating the enthalpy value at the inlet of the cold end of the heat exchanger and the enthalpy value at the outlet of the cold end of the heat exchanger;

[0012] calculating the heat exchange amount of the heat exchanger according to the enthalpy value at the inlet of the cold end of the heat exchanger and the enthalpy value at the outlet of the cold end of the heat exchanger;

[0013] calculating the enthalpy value at the inlet of the hot end of the heat exchanger and the enthalpy value at the outlet of the hot end of the heat exchanger;

[0014] calculating the flow of the working medium at the hot end of the heat exchanger, i.e. the leakage flow of the drain valve, according to the heat exchange amount of the heat exchanger and the enthalpy value at the inlet of the hot end of the heat exchanger and the enthalpy value at the outlet of the hot end of the heat exchanger.

[0015] Preferably, the method for calculating the enthalpy value h9 at the inlet of the cold end of the heat exchanger and the enthalpy value h8 at the outlet of the cold end of the heat exchanger is as follows:

[0016] h9 = f (P a , T9)

[0017] h8 = f (P a , T8)

[0018] wherein P a is the pressure of the circulating pump, i.e. the pressure at the inlet and outlet of the cold end of the heat exchanger, T9 is the temperature at the inlet of the cold end of the heat exchanger, and T8 is the temperature at the outlet of the cold end of the heat exchanger.

[0019] Preferably, the method for calculating the heat exchange amount Q of the heat exchanger is as follows:

[0020] Q = m a (h8 - h9)

[0021] wherein m a is the outlet water flow of the circulating pump, h9 is the enthalpy value at the inlet of the cold end of the heat exchanger, and h8 is the enthalpy value at the outlet of the cold end of the heat exchanger.

[0022] Preferably, the method for calculating the enthalpy value h6 at the inlet of the hot end of the heat exchanger and the enthalpy value h7 at the outlet of the hot end of the heat exchanger is as follows:

[0023] h6 = f (P b , T6)

[0024] h7 = f (P b , T7)

[0025] wherein P bT6 is the temperature of the inlet of the hot end of the heat exchanger, and T7 is the temperature of the outlet of the hot end of the heat exchanger.

[0026] Preferably, the calculation of the leakage flow m of the hydrophobic valve b The method is as follows:

[0027] Q=m b (h6-h7)

[0028] Wherein, Q is the heat exchange amount of the heat exchanger, h6 is the enthalpy value of the inlet of the hot end of the heat exchanger, and h7 is the enthalpy value of the outlet of the hot end of the heat exchanger.

[0029] Preferably, the fluid working medium of the cold end of the heat exchanger is water.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application realizes the detection of the leakage amount of the hydrophobic valve by installing a leakage amount detection unit at the output end of the hydrophobic valve, so as to realize the evaluation of the economy and safety of the actual unit working condition. Through the setting of the circulating pump and the radiator in the leakage amount detection unit, the effective circulation of the working medium of the cold end of the heat exchanger is realized, the energy-saving and efficiency-improving effect is achieved, and the real-time detection of the leakage amount of the hydrophobic valve is realized.

[0032] The present application provides a kind of heat system hydrophobic valve leakage measurement method, which calculates the leakage amount of the hydrophobic valve according to the heat conservation principle by calculating the heat exchange amount of the heat exchanger, the calculation principle is simple, clear, system is simple and reasonable, without other auxiliary equipment, with high accuracy and practicality, is the energy-saving and efficiency-improving innovative technology. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0034] Figure 1 It is a structural schematic diagram of the hydrophobic valve leakage measurement system of the present application.

[0035] Figure 2 It is a flowchart of the hydrophobic valve leakage measurement method of the present application.

[0036] Wherein: 1- hydrophobic pipeline, 2- hydrophobic valve, 3- heat exchanger, 4- radiator, 5- circulating pump, 6- hot end inlet temperature measuring element, 7- hot end outlet temperature measuring element, 8- cold end outlet temperature measuring element, 9- cold end inlet temperature measuring element. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0042] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0043] The application will be described in further detail below with reference to the drawings:

[0044] Referring to Figure 1 , the application installs a leakage amount detection unit on the drain pipe 1 connected to the output end of the drain valve 2, which includes a heat exchanger 3, a radiator 4, a circulating pump 5, a hot-end inlet temperature measuring element 6, a hot-end outlet temperature measuring element 7, a cold-end outlet temperature measuring element 8 and a cold-end inlet temperature measuring element 9.

[0045] Firstly, when the fluid working substance flows into the drain pipe 1, passes through the drain valve 2 and enters the heat exchanger 3 arranged at the output end of the drain valve, the circulating pump 5 runs at a constant speed, so that the cold-end fluid working substance flow m a of the heat exchanger 3 cold-end inlet and outlet is basically kept unchanged, and the pressure of the heat exchanger 3 cold-end inlet and outlet is the pressure P a of the circulating pump 5 outlet. It is known that the circulating pump 5 pumps out the cold-end fluid working substance from the heat exchanger 3 cold-end outlet, radiates the cold-end fluid working substance through the radiator 4, and then pumps the cold-end fluid working substance into the heat exchanger 3 through the heat exchanger 3 cold-end inlet to exchange heat, at this time, the temperature measured by the cold-end inlet temperature measuring element 9 at the heat exchanger 3 cold-end inlet is T9. After the heat exchange through the heat exchanger 3, the cold-end fluid working substance flows out through the heat exchanger 3 cold-end outlet, at this time, the temperature measured by the cold-end outlet temperature measuring element 8 is T8. The fluid working substance is radiated through the radiator 4 and then enters the circulating pump again to repeat the cycle. At this time, according to the pressure P a of the heat exchanger 3 cold-end inlet and outlet, the heat exchanger 3 cold-end inlet temperature T9 and the heat exchanger 3 cold-end outlet temperature T8, the enthalpy values of the heat exchanger 3 cold-end inlet and outlet are calculated as h9 and h8 respectively, and then the heat exchange amount Q of the heat exchanger can be calculated through the formula:

[0046] Q = m a (h8-h9)

[0047] At the same time, when the fluid working substance enters the drain pipe 1, passes through the drain valve 2 and enters the heat exchanger 3 hot-end inlet, the pressure P b of the drain pipe is known, at this time, the temperature measured by the heat exchanger 3 hot-end inlet temperature measuring element is T6. After the heat exchange through the heat exchanger 3, the hot-end fluid working substance enters the drain pipe 1 through the heat exchanger 3 hot-end outlet, at this time, the temperature measured by the heat exchanger 3 hot-end outlet temperature measuring element is T7, according to the temperature T6 and T7 of the heat exchanger 3 hot-end inlet and outlet and the pressure P b of the drain pipe 1, the enthalpy values of the heat exchanger 3 hot-end inlet and outlet are calculated as h6 and h7 respectively by using the thermodynamic property calculation formula of the hot-end fluid working substance, and then the drain valve leakage flow m b can be calculated through the formula according to the heat balance:

[0048] Q = m a (h8-h9) = m b (h6-h7)

[0049] When the heat exchanger 3 cold end fluid working substance and the heat exchanger 3 hot end fluid working substance are both water, the circulating pump 5 runs at a constant speed, and the water flow rate m a through the heat exchanger 3 cold end inlet and outlet is known to be 0.5 kg / s, and the pressure P a at the circulating pump 5 outlet is the pressure at the heat exchanger 3 cold end inlet and outlet, which is 0.5 MPa. When the water is pumped into the heat exchanger 3 by the circulating pump 5, the temperature T9 measured by the heat exchanger 3 cold end inlet temperature measuring element 9 is 20°C. When the water is heated by the heat exchanger 3 and passes through the heat exchanger 3 cold end outlet, the temperature T8 of the water measured by the heat exchanger 3 cold end outlet temperature measuring element 8 is 30°C. According to the water temperatures T9 and T8 at the heat exchanger 3 cold end inlet and outlet and the pressure P a at the heat exchanger 3 cold end inlet and outlet, the enthalpy values h9 and h8 of the water at the heat exchanger 3 cold end inlet and outlet can be calculated by the formulas and, respectively, using the thermodynamic properties of water and water vapor:

[0050] h9 = f = 84.3 kJ / kg

[0051] h8 = f = 126.1 kJ / kg

[0052] The heat exchange amount Q of the heat exchanger 3 can be calculated according to the formula as follows:

[0053] Q = m a (h8 - h9) = 0.5 * (126.1 - 84.3) = 20.9 kW

[0054] At the same time, when the water enters the drain pipe 1 and passes through the heat exchanger 3 hot end inlet through the drain valve 2, the pressure P b of the drain pipe 1 is known to be 0.7 MPa according to the working unit data, and the temperature T6 measured by the heat exchanger 3 hot end inlet temperature measuring element 6 is 180°C at this time. When the water is heated by the heat exchanger 3 and flows into the water delivery pipe 1 through the heat exchanger 3 hot end outlet, the temperature T7 measured by the heat exchanger 3 hot end outlet temperature measuring element 7 is 150°C at this time. According to the temperatures T6 and T7 at the heat exchanger 3 hot end inlet and outlet and the pressure P b of the drain pipe 1, the enthalpy values h6 and h7 of the water at the heat exchanger 3 hot end inlet and outlet can be calculated by the formulas and, respectively, using the thermodynamic properties of water and water vapor:

[0055] h6 = f = 2798.0 kJ / kg

[0056] h7 = f = 2724.7 kJ / kg

[0057] According to the heat balance principle, the drain valve leakage flow rate m b can be calculated by the formula as follows:

[0058] Q = m a (h8-h9) = m b (h6-h7)

[0059] 20.9 kW = m b (2798.0 kJ / kg - 2724.7 kJ / kg)

[0060] m b = 0.285 kg / s

[0061] Then, at this time, the leakage flow rate m b of the steam trap is 0.285 kg / s.

[0062] The steam trap leakage measurement system and method of the heat system can more accurately measure the leakage flow rate of the steam trap, so that the technical personnel can evaluate the economic and safety influence brought by the steam trap leakage according to the measured leakage flow rate of the steam trap, the calculation principle is clear, the system structure is simple, the operability is strong, it is helpful for the unit dynamic monitoring, can improve the unit operation economy, and is an innovative technology suitable for all energy-saving and efficiency-improving working units with steam traps.

[0063] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for measuring the leakage of a steam trap of a heating system, based on a system for measuring the leakage of a steam trap of a heating system, the system comprising a leakage detection unit arranged on a steam pipe (1), the leakage detection unit being arranged at the output end of a steam trap (2) and comprising a heat exchanger (3), a heat sink (4), a circulating pump (5), a hot-end inlet temperature measuring element (6), a hot-end outlet temperature measuring element (7), a cold-end inlet temperature measuring element (9) and a cold-end outlet temperature measuring element (8); the hot-end inlet of the heat exchanger (3) is connected to the output end of the steam trap (2) through the steam pipe (1); the hot-end inlet temperature measuring element (6) is arranged on the steam pipe (1) between the hot-end inlet of the heat exchanger (3) and the output end of the steam trap (2), and the hot-end outlet temperature measuring element (7) is arranged on the steam pipe (1) at the hot-end outlet of the heat exchanger (3); the cold-end outlet of the heat exchanger (3) is connected to the heat sink (4) and the circulating pump (5) in sequence, and the output end of the circulating pump (5) is connected to the cold-end inlet of the heat exchanger (3); the cold-end outlet temperature measuring element (8) is arranged between the cold-end outlet of the heat exchanger (3) and the inlet of the heat sink (4), and the cold-end inlet temperature measuring element (9) is arranged between the circulating pump (5) and the cold-end inlet of the heat exchanger (3); the method comprises the following steps: calculating the enthalpy value at the cold-end inlet of the heat exchanger (3) and the enthalpy value at the cold-end outlet of the heat exchanger (3); calculating the heat exchange amount of the heat exchanger (3) according to the enthalpy value at the cold-end inlet of the heat exchanger (3) and the enthalpy value at the cold-end outlet of the heat exchanger (3); calculating the enthalpy value at the hot-end inlet of the heat exchanger (3) and the enthalpy value at the hot-end outlet of the heat exchanger (3); calculating the flow of the hot-end fluid working medium of the heat exchanger (3), i.e. the leakage flow of the steam trap, according to the heat exchange amount of the heat exchanger (3) and the enthalpy value at the hot-end inlet of the heat exchanger (3) and the enthalpy value at the hot-end outlet of the heat exchanger (3); and the circulating pump (5) is a constant-speed circulating pump. The cold-end fluid working medium of the heat exchanger (3) is water. ​ characterized in that ​ ​ ​ ​ ​ The calculated heat exchanger (3) cold end inlet enthalpy h 9 and heat exchanger (3) cold end outlet enthalpy h 8 is as follows: h 9= f ( P a , T 9) h 8= f ( P a , T 8) wherein, P a P is the pressure of the circulation pump (5), i.e. the pressure at the inlet and outlet of the cold side of the heat exchanger (3), T 9 is the temperature at the inlet of the cold side of the heat exchanger (3), T 8 is the temperature at the outlet of the cold side of the heat exchanger (3). The method of calculating the heat exchange amount of the heat exchanger (3) Q The method is as follows: Q = m a ( h 8- h 9) wherein, m a is the outlet water flow rate of the circulation pump (5), h 9 is the enthalpy value at the cold end inlet of the heat exchanger (3), h 8 is the enthalpy value at the cold end outlet of the heat exchanger (3). The calculated heat exchanger (3) hot end inlet enthalpy h 6 and heat exchanger (3) hot end outlet enthalpy h 7 is as follows: h 6= f ( P b , T 6) h 7= f ( P b , T 7) wherein, P b P2 is the pressure at the hot end inlet of the heat exchanger (3), T 6 is the temperature at the hot end inlet of the heat exchanger (3), T 7 is the temperature at the hot end outlet of the heat exchanger (3). The computing hydrophobic valve leakage flow m b The method is as follows: Q = m b ( h 6- h 7) wherein, Q Q is the heat exchange amount of the heat exchanger (3), h 6 is the enthalpy value of the heat exchanger (3) at the hot end inlet, h 7 is the enthalpy value of the heat exchanger (3) at the hot end outlet.

2. The method of claim 1, wherein, ​ 3. The method of claim 1, wherein, ​

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