Method for rapidly determining leaked water cooler in ethylene device by using online detection and identification technology

Abstract

The invention discloses a method for rapidly determining a leaked water cooler in an ethylene device by using an online detection and identification technology, and relates to the field of water cooler leakage monitoring. Comprising the following steps: selecting a process medium component of the water cooler as a characteristic component; constructing a fingerprint spectrogram database of the characteristic components; the circulating water of the water cooler is quantitatively and qualitatively analyzed in real time by utilizing an online detection technology, and a qualitative detection spectrogram result is compared and identified by utilizing an identification technology, so that the leaked water cooler is found. According to the method, different process media in different water coolers are utilized, the leaked process media in the circulating water and the water cooler characteristic component spectrogram database are compared and analyzed through the online detection and recognition technology, so that the water cooler with the leaked process media is locked, the leakage detection speed is high, the efficiency is high, the application range is wide, accurate information is provided for timely leaking stoppage, and the method is suitable for popularization and application. Deterioration of circulating cooling water quality is avoided, and normal operation of a production device is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of water cooler leakage monitoring, and in particular to a method for quickly determining a leaking water cooler in an ethylene device by using online detection and identification technology. Background Art

[0002] The circulating cooling water system is a public engineering system that uses water as a cooling medium for continuous circulation. It is the "blood" of the entire chemical enterprise and plays a very important role. In the industrial circulating water system, due to the continuous evaporation and concentration of water, material leakage, and the appropriate water temperature, it is very suitable for the growth of microorganisms, resulting in the massive reproduction of bacteria, fungi and algae. These microorganisms produce a large amount of biological slime attached to the water cooler, seriously affecting the heat exchange efficiency, and causing serious under-scaling corrosion, threatening the normal operation of the production equipment.

[0003] Leakage of process media from water coolers is a common phenomenon in chemical plants and a headache for enterprises. Once the leaked process media enters the circulating water system, it will cause water quality deterioration, resulting in serious corrosion of the water cooler and a significant reduction in heat exchange efficiency, affecting the normal operation of the production equipment, causing economic losses or even major losses to the enterprise, and thus attracting great attention from enterprises. However, due to the large number of water coolers in the circulating water system, the complex heat exchange system, and the various components of the process media, leak detection is very troublesome and inefficient. It usually takes a long time to find the leak point, and often the leak point has not been found yet, and the circulating water quality has deteriorated.

[0004] The design and manufacturing technology level of water coolers in foreign chemical plants is relatively high, and the material grade used is also high. The problem of process medium leakage during water cooler operation has been solved relatively well, so there are few related water cooler leak detection technologies. The situation in China is completely different from that in foreign countries. The phenomenon of process medium leakage in water coolers is relatively common, which has led to the development of related analytical technologies for water cooler leak detection. The main analytical methods currently used for leak detection of circulating water system water coolers are: infrared photometry, ultraviolet spectrophotometry, fluorescence turbidity, gravimetric method, gas chromatography, laser fiber technology, redox potential method and related online monitoring technologies.

[0005] The problem with the offline detection technology for process media leakage in circulating water systems currently developed and used is that it cannot quickly and accurately determine the leakage point. In addition, the offline technology is very inconvenient to use, complicated to operate, takes a long time to analyze, has many influencing factors, and the results are inaccurate, which cannot meet actual production needs. Summary of the invention

[0006] The present invention provides a method for quickly determining a leaking water cooler in an ethylene device by using online detection and identification technology. Since different water coolers have different process media, the online detection and identification technology is used to determine the properties of the leaking process medium to quickly and accurately determine the leakage of the water cooler in the ethylene device.

[0007] In order to solve the above technical problems, the present invention provides a method for quickly determining a leaking water cooler in an ethylene device using online detection and identification technology, comprising the following steps:

[0008] (1) Selecting process medium components of different water coolers in an ethylene plant as characteristic components;

[0009] (2) Establish detection corresponding spectra of different characteristic components and construct a “fingerprint” spectrum database of characteristic components;

[0010] (3) Use online detection technology to conduct real-time quantitative and qualitative analysis of the circulating water of the water cooler. When the process medium entering the circulating water is detected, the identification technology is used to compare and identify the qualitative detection spectrum results with the characteristic component spectrum in the "fingerprint" spectrum database to find the series or parallel water cooler that has leaked.

[0011] As a preferred embodiment, in step (1), 2-3 components in the process medium of different water coolers in the ethylene plant are selected as characteristic components.

[0012] As a preferred solution, in step (3), online detection technology is used to perform real-time quantitative and qualitative analysis on water samples in the return water main of the water cooler circulating water system.

[0013] As a preferred solution, in step (3), after determining the water coolers in series or parallel in which the process medium has leaked, a water sample is taken from the inlet and outlet of each water cooler in series or parallel for quantitative analysis of COD or determination of its redox potential, and the results are compared with the daily analysis results. If there is a leak, the COD and redox potential parameters will change significantly, and whether there is a leak can be quickly determined by whether there is a significant change.

[0014] As a preferred solution, in step (3), a water sample is taken from the inlet and outlet of each water cooler connected in series or parallel to quantitatively analyze the COD or determine its redox potential. The COD must fluctuate by at least 40 mg / L compared with the daily analysis result to determine the presence of a leak, and the redox potential must fluctuate by 50-100 mV compared with the daily analysis result to determine the presence of a leak.

[0015] Since the process media in the water coolers connected in series or parallel are the same, that is, they have the same characteristic components, the online detection technology of this application measures the water samples in the return water main of the circulating water system. After the detection results of the main pipe show that there is a process medium leakage, water samples from the inlet and outlet of all water coolers corresponding to the process medium should be taken for detection and verification to determine a specific water cooler.

[0016] As a preferred solution, in step (2), corresponding gas-phase infrared characteristic spectra of different characteristic components are established, and a "fingerprint" spectrum database of infrared characteristic spectra of characteristic components is constructed.

[0017] As a preferred solution, in step (3), the circulating water of the water cooler is analyzed in real time using online detection technology, and the information is quickly reported to the monitoring station through DCS communication, providing accurate information for timely plugging of leaks.

[0018] As a preferred solution, in step (3), the online detection technology is gas lift-infrared online detection technology.

[0019] As a preferred solution, in step (3), the identification technology is the classical least squares method. Compared with the prior art, the present invention has the following beneficial effects:

[0020] This application obtains the characteristic spectrum of the leaked process medium through online detection, compares and analyzes the characteristic component spectrum of the process medium in the water cooler through identification technology, quickly and accurately locks the properties of the leaking process medium, and thus locks the water cooler where the process medium is leaking. This method has a fast leak detection speed, high efficiency, and a wide range of applications. Based on the high precision and high accuracy of online detection and identification technology, it can detect trace amounts of process media entering the circulating water, provide accurate information for timely plugging leaks, avoid deterioration of the circulating cooling water quality, ensure long-term operation of production equipment, achieve cost reduction and efficiency improvement, improve the operating level of circulating cooling water, and ensure the normal operation of production equipment. It is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 :This is the heat exchange flow chart of the process medium water cooler of the ethylene cracking unit. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0023] The process conditions of ethylene plant are very complex. Different process media require different conditions for water cooling and heat exchange, forming a water cooling heat exchange network, such as Figure 1 It is a schematic diagram of the partial water-cooling heat exchange process of the 2# cracking unit. Some gaseous process media are converted into liquid process media through water coolers, or high-temperature process media are cooled down to low-temperature process media through water coolers. Most process media are cooled by single-stage parallel water coolers, and some process media need to be cooled by multi-stage series water coolers for water-cooling heat exchange.

[0024] There are many large and small water coolers in ethylene plants, up to hundreds of them, and the process media components cooled by different water coolers are different and complex. In order to quickly and accurately determine the water cooler that leaked the process media by detecting the process media leaking into the circulating water, it is necessary to first select the characteristic components in the process media cooled by different water coolers, and then use online detection and identification technology to obtain the information of these characteristic components, so as to quickly and accurately determine the water cooler that leaked the process media.

[0025] Embodiment 1

[0026] A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology specifically comprises the following steps:

[0027] (1) There are two kinds of media in the water cooler, which flow through the tube layer and shell layer of the water cooler respectively. One is cooling water (i.e., circulating water) and the other is the cooled medium (i.e., process medium). The components that can be detected in the process medium are the characteristic components. First, 2-3 components in the process medium cooled by different water coolers in Table 1 are selected as characteristic components;

[0028] (2) Establish the corresponding gas-phase infrared characteristic spectra of different characteristic components and construct the infrared "fingerprint" spectrum database of characteristic components;

[0029] (3) Finally, the gas lift-infrared online detection technology is used to perform real-time detection and analysis of water samples in the return water main of the circulating water system. The trace amount of process medium entering the circulating water can be detected online quantitatively and qualitatively, and the infrared characteristic spectrum of the characteristic components lifted into the gas phase is collected. When the process medium entering the circulating water is detected, it is quickly reported to the monitoring station through DCS communication. The classical least squares (CLS) recognition technology is used to compare and identify the infrared characteristic spectrum results of the qualitative detection with the infrared "fingerprint" spectrum database to determine its component properties and process medium name, and compare them with Table 1. The water cooler corresponding to the leaking process medium property is locked, so as to quickly find the series or parallel water cooler with leakage;

[0030] (4) After determining the water cooler in series or parallel where the process medium is leaking, take a water sample from the inlet and outlet of each water cooler in series or parallel to quantitatively analyze the COD or determine its redox potential. If there is a leak, the COD and redox potential parameters will change significantly. Compare them with the daily analysis results to quickly determine whether there is a leak by whether there is a significant change. The COD must fluctuate by at least 40 mg / L compared with the daily analysis results to determine the presence of a leak, and the redox potential must fluctuate by 50-100 mV compared with the daily analysis results to determine the presence of a leak. This allows the specific water cooler where the process medium is leaking to be quickly and accurately determined.

[0031] Table 1 - Process medium components in some water coolers in ethylene cracking units

[0032]

[0033]

[0034] Table 2 is the detailed information of the water cooler leakage detection in the ethylene cracking unit using the technical solution of this application in 2022-2023

[0035]

[0036] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology, characterized in that: The following steps are involved: (1) Selecting process medium components of different water coolers in an ethylene plant as characteristic components; (2) Establish detection corresponding spectra of different characteristic components and construct a "fingerprint" spectrum database of characteristic components; (3) Use online detection technology to conduct real-time quantitative and qualitative analysis of the circulating water of the water cooler. When the process medium entering the circulating water is detected, the identification technology is used to compare and identify the qualitative detection spectrum results with the characteristic component spectrum in the "fingerprint" spectrum database, so as to find the series or parallel water cooler with leakage.

2. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (1), 2-3 components in the process medium of different water coolers in the ethylene plant are selected as characteristic components.

3. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (3), online detection technology is used to perform real-time quantitative and qualitative analysis on water samples in the return water main of the water cooler circulating water system.

4. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 3, characterized in that: In step (3), after determining the water coolers in series or parallel where the leaking process medium occurs, take a water sample from the inlet and outlet of each water cooler in series or parallel for quantitative analysis of COD or determination of its redox potential, and compare them with the daily analysis results. If there is a leak, the COD and redox potential parameters will change significantly, and whether there is a leak can be quickly determined by whether there is a significant change.

5. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 4, characterized in that: In step (3), a water sample is taken from the inlet and outlet of each water cooler connected in series or parallel to quantitatively analyze the COD or determine its redox potential. The COD must fluctuate by at least 40 mg / L compared with the daily analysis result to determine the presence of a leak, and the redox potential must fluctuate by 50-100 mV compared with the daily analysis result to determine the presence of a leak.

6. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (2), corresponding gas-phase infrared characteristic spectra of different characteristic components are established, and a "fingerprint" spectrum database of infrared characteristic spectra of characteristic components is constructed.

7. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (3), the circulating water of the water cooler is analyzed in real time using online detection technology, and the information is quickly reported to the monitoring station through DCS communication, providing accurate information for timely plugging of leaks.

8. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (3), the online detection technology is gas lift-infrared online detection technology.

9. A method for quickly identifying a leaking water cooler in an ethylene plant using online detection and identification technology as claimed in claim 1, characterized in that: In step (3), the identification technique is the classical least squares method.

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