Leakage detection device for heat exchanger of waste heat boiler

Abstract

The utility model discloses a waste heat boiler heat exchanger leakage detection device, which belongs to the technical field of waste heat boiler leakage detection and comprises a waste heat boiler and a heat exchanger, the waste heat boiler and the heat exchanger are connected through a heat exchanger steam side steam inlet pipeline electric door, and the waste heat boiler is further connected with a gas filling pipe through a mixed gas filling port manual door. The gas inlet end of the gas filling pipe is connected with a helium bottle and a compressed air inlet pipe, and a helium mass spectrum detector is arranged in a heat exchanger tube bundle on the heat exchanger. The positive pressure method helium detection technology is adopted, a helium mass spectrometer is used for detecting the heat transfer pipes of the heat exchanger one by one from the lower portion to the upper portion, firstly, the expansion welding portion of each heat transfer pipe is detected, whether leakage exists in the pipe wall of the heat transfer pipe or not is detected after it is confirmed that no leakage exists, and if leakage exists in the expansion welding portions of the heat transfer pipes, leakage is detected. The display value of the detector changes immediately, the leakage part is marked by a marking pen, and after the detector returns to the zero position, the internal leakage condition of the pipe wall of the heat transfer pipe starts to be detected.

Description

Technical Field

[0001] The utility model belongs to the technical field of waste boiler leakage detection, in particular to a waste boiler heat exchanger leakage detection device. Background Art

[0002] Waste boiler refers to a part of waste heat boiler, which is mainly used for the reaction heat generated in the chemical production process. It is a boiler that uses various waste heat to generate steam, also called waste heat boiler. Generally refers to the reuse of waste media with relatively high heat content, or refers to the reuse of waste media with relatively high heat content, the purpose of which is to save energy and reduce consumption. In order to make full use of this part of high-temperature steam (or other high-temperature media), chemical companies use convection heat exchange, which includes shell and tube type, tube-in-tube type, and spray type. Now most of them use tube-in-tube type, which has a large heat exchange area and good effect. The shell and tube type process gas goes through the tube room, and the circulating water goes outside the tube. The tube-in-tube type process gas goes through the shell column, and the water goes through the tube room. Chemical companies use the high-temperature circulating gas at the outlet of the synthesis tower to exchange heat with deoxygenated water, recover heat, reduce the outlet temperature of the synthesis tower, and achieve the purpose of secondary energy utilization. However, it is common that heat exchange devices are prone to leakage, which causes extremely unfavorable safety hazards to chemical companies. Utility Model Content

[0003] The utility model provides a waste boiler heat exchanger leakage detection device, which is aimed at solving the problem of leakage of the waste boiler heat exchanger and completely eliminating it, so as to ensure the long-term safe operation of equipment in chemical enterprises.

[0004] The technical solution adopted by this utility model:

[0005] A waste boiler heat exchanger leakage detection device comprises a waste boiler and a heat exchanger, wherein the waste boiler and the heat exchanger are connected through an electric door of a steam inlet pipeline on a steam side of the heat exchanger, and the waste boiler is also connected to an inflation pipe through a manual door of a mixed gas filling inlet, and the gas inlet end of the inflation pipe is respectively connected to a helium cylinder and a compressed air inlet pipe.

[0006] In the above technical solution, the positive pressure zone of the heat exchanger is connected with a drain electric door and a steam return electric door.

[0007] In the above technical solution, further, a helium mass spectrometer is built into the heat exchanger tube bundle tube on the heat exchanger.

[0008] Compared with the prior art, the beneficial effects of the utility model are:

[0009] The chemical production waste boiler heat exchanger leakage detection device proposed by the utility model can detect and eliminate the leakage problem of the waste boiler heat exchanger, ensuring the long-term safe operation of chemical enterprise equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 The utility model provides a system connection diagram of a leakage detection device for a waste boiler heat exchanger in a chemical production.

[0012] Explanation of the reference numerals: 1-electric door of the steam inlet pipe on the steam side of the heat exchanger; 2-electric door for draining water; 3-electric door for returning steam; 4-heat exchanger; 5-manual door for the mixed gas charging inlet. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] The utility model provides a leakage detection device for a waste heat exchanger in a chemical production process, such as Figure 1 As shown, it includes a waste boiler and a heat exchanger. The waste boiler and the heat exchanger are connected through an electric door of a steam inlet pipe on the steam side of the heat exchanger. The other side of the waste boiler is connected to a charging pipe through a manual door of a mixed gas charging inlet. The air inlet end of the charging pipe is respectively connected to a helium cylinder and a compressed air inlet pipe, and the compressed air inlet pipe can be connected to a compressed air machine.

[0016] The positive pressure area of ​​the heat exchanger is connected with a drain electric door and a steam return electric door. The heat exchanger tube bundle on the heat exchanger is equipped with a helium mass spectrometer. The helium mass spectrometer is used to conduct a comprehensive inspection of the heat exchanger tube bundle ports one by one, and the inspection probe is used to inspect the heat exchanger tube bundle from the top to the bottom one by one.

[0017] Heat exchanger testing process:

[0018] 1. When the compressed air and helium mixed gas is pressed to a pressure of not less than 3kpa, close the electric door 1 of the steam inlet pipe on the steam side of the heat exchanger. There is a pressure gauge at the electric door 1 of the steam inlet pipe on the steam side of the heat exchanger. The pressure gauge can be used to observe whether the electric door 1 of the steam inlet pipe on the steam side of the isolation heat exchanger is closed tightly. When detecting heat exchanger leakage, the pressure gauge can be used to observe whether the electric door 1 of the steam inlet pipe on the steam side of the isolation heat exchanger is closed. If the pressure gauge shows that the electric door 1 of the steam inlet pipe on the steam side of the isolation heat exchanger is not closed tightly, switch to the manual position on the spot to close the electric door, and temporarily install a blocking plate if necessary.

[0019] 2. Isolate and close all drain electric doors 2 and steam return electric doors 3 in the positive pressure area of ​​the heat exchanger. If the steam side electric door is not tight (pressure gauge detection), switch to the manual position on the spot to close the electric door to ensure tight sealing. Drain electric door 2 is used to recover the water vapor condensed from the gas on the heat exchanger, and steam return electric door 3 is used to recover the exhaust gas. Both are conventional structures on the heat exchanger, and no improvement is made here.

[0020] 3. Isolate and close the exhaust door on the steam side of the heat exchanger.

[0021] 4. Use compressed air to establish positive pressure on the shell side of the heat exchanger, and fill compressed air with a pressure of 2.5Kpa from the manual door 5 of the mixed gas filling inlet (if the amount of compressed air on site does not meet the demand, use a compressed air machine to supplement it), pressurize it to 2.5-3Kpa pressure (less than the shell side working pressure), and keep the mixed gas pressure on the shell side of the heat exchanger not exceeding 3Kpa pressure; if the system is not tight during isolation, you can take the method of adding compressed air multiple times after the mixed gas pressure drops to 2Kpa pressure (until the mixed gas pressure is not less than 2.5Kpa), and adding compressed air will not affect the detection work. There is a small amount of water inside the heat exchanger, which will not affect the detection accuracy.

[0022] 5. Fill helium through the manual door 5 of the mixed gas filling inlet. The concentration time of helium is required to be controlled within 15 seconds. If a pipe or tube bundle leaks, the molecular weight of helium at the detector probe exceeds the zero value of the detector 1.0E-08mbar.L / s, and the data display of the detector will change significantly. The detected leakage points should be accurately marked and recorded.

[0023] 6. After the compressed air and helium are filled to the required pressure according to the above method, the inspection technicians enter the inspection position of the heat exchanger tube sheet and start to inspect the heat transfer tubes of the heat exchanger one by one from the bottom to the top. First, inspect the expansion welding part of each heat transfer tube. After confirming that there is no leakage, inspect whether there is leakage inside the tube wall of the heat transfer tube. If there is leakage at the expansion welding part of the heat transfer tube, the display value of the detector will change immediately. Mark the leaking part with a marker. After the detector is reset to zero, start to inspect the internal leakage of the tube wall of the heat transfer tube (the instrument display will not return to zero for more than 5 seconds). Inspect the heat transfer tube bundles of the heat exchanger one by one according to the above inspection sequence.

[0024] 7. For any leaking pipe bundles found, seal them with copper plugs after confirmation. After sealing, perform helium testing again to ensure that all leaking pipe bundles are leak-free after treatment.

[0025] Detection principle of helium mass spectrometer: Helium mass spectrometer leak detector is an airtightness detection instrument made according to the principle of mass spectrometry, using helium as the leak indicator gas. It consists of a mass spectrometer chamber composed of an ion source, an analyzer, a collector, a cold cathode ionization gauge, an exhaust system, and an electrical part. It is a leak detector working on the countercurrent principle. By injecting helium at the system detection point and detecting the molecular weight of helium from the exhaust pipe, it can be judged whether the system has a leak.

[0026] Measuring instrument background: 1.0E-8mbar.L / s

[0027] Instrument display: 1.0E-7 to 3.0E-6 for small leakage

[0028] 3.0E-6 to 5.0E-5 is medium leakage

[0029] 5.0E-5 to 2.0E-4 is a large leakage

[0030] 2.0E-4 or above is considered a very large leakage

[0031] The above is only a preferred embodiment of the utility model and does not limit the utility model in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the utility model still falls within the protection scope of the technical solution of the utility model.

Claims

1. A waste boiler heat exchanger leakage detection device, comprising a waste boiler and a heat exchanger, wherein the waste boiler and the heat exchanger are connected through an electric door of a steam inlet pipe on the steam side of the heat exchanger, characterized in that: The waste boiler is also connected with a gas charging pipe through a manual door of the mixed gas charging inlet, and the gas inlet end of the gas charging pipe is respectively connected with a helium cylinder and a compressed air inlet pipe.

2. A waste boiler heat exchanger leakage detection device according to claim 1, characterized in that: The positive pressure area of ​​the heat exchanger is connected with a drain electric door and a steam return electric door.

3. A waste boiler heat exchanger leakage detection device according to claim 2, characterized in that: The heat exchanger tube bundle on the heat exchanger has a helium mass spectrometer built into it.

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