Cleaning method and cleaning system for removing stickers of shell-and-tube heat exchanger

Abstract

The invention discloses a cleaning method and a cleaning system for removing stickers of a shell-and-tube heat exchanger. The cleaning method comprises the following steps: S1, preparing a dissolving solvent for dissolving the stickers and a cleaning solvent for cleaning the dissolving solvent and the stickers; s2, a material pipeline of the shell-and-tube heat exchanger is washed with clear water, then is filled with a dissolving solvent for soaking treatment, then is discharged out of the dissolving solvent, is filled with a cleaning solvent for soaking treatment, and finally is discharged out of the cleaning solvent; s3, a dissolving solvent is used for circularly dissolving a material pipeline of the tubular heat exchanger, and then the dissolving solvent is discharged; s4, circularly cleaning the material pipeline of the shell-and-tube heat exchanger by using the cleaning solvent, and then discharging the cleaning solvent; and S5, washing a material pipeline of the shell-and-tube heat exchanger by using clear water, and then blow-drying by using air. The method can effectively clean the stickers in the shell-and-tube heat exchanger with less manual labor, recovers the heat exchange efficiency of the heat exchanger, is extremely low in medicament residue content, and does not affect the subsequent use.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchanger maintenance, and in particular to a cleaning method and a cleaning system for removing adhesives from a shell-and-tube heat exchanger. Background Art

[0002] In the pharmaceutical, chemical, environmental protection and other industries, heating is often required for reaction, and heating reactions require the use of heat exchangers for heat exchange. Under conditions where there are a lot of organic matter or organic matter needs to be added, after frequent heating of the heat exchanger, the organic matter aggregates and denatures, resulting in a large amount of adhesives adhering to the heat exchanger tubes, which deteriorates the heat exchange efficiency of the tubes. The attached organic matter increases over time, and the thickness increases, causing the heat exchanger to be blocked, affecting normal production.

[0003] At present, the industry tends to use physical methods to clean the tubes, mainly through high-pressure water washing, while solvent cleaning is rarely used. This is mainly due to the consideration that the residual solvent will introduce organic impurities that affect the normal use of the heat exchanger.

[0004] Patent application CN118816626A discloses a cleaning method for the inner wall of copper-nickel tubes of shell-and-tube heat exchangers, which uses 0.5-5% citric acid as a reagent for soaking and washing, providing an option for efficiently solving the maintenance of ship shell-and-tube heat exchangers. This method is only suitable for washing salt scale produced by inorganic substances, and has no effect on organic matter or adhesive substances. Summary of the invention

[0005] The main purpose of the present invention is to provide a cleaning method and a cleaning system for removing adhesives from a shell-and-tube heat exchanger, which have good adhesive removal effect and extremely low reagent residue.

[0006] To achieve the above object, the present invention provides a cleaning method for removing adhesives from a shell and tube heat exchanger, comprising the following steps: S1: Preparation of cleaning agent preparing a dissolving solvent for dissolving the stickies and a cleaning solvent for cleaning the dissolving solvent and the stickies; S2: Soaking and dissolving The material pipeline of the shell and tube heat exchanger is first flushed with clean water, then emptied of the clean water, filled with a dissolving solvent for soaking, then the dissolving solvent is drained, then filled with a cleaning solvent for soaking, and finally the cleaning solvent is drained; S3: Cycle Dissolution Using a dissolving solvent to circulate and dissolve the material pipeline of the shell and tube heat exchanger, and then discharging the dissolving solvent; S4: Circulation cleaning Use cleaning solvent to circulate and clean the material pipeline of the shell and tube heat exchanger, and then discharge the cleaning solvent; S5: Clean water Rinse the material lines of the shell and tube heat exchanger with clean water and then blow dry with air.

[0007] Furthermore, in step S1, the dissolving solvent is a mixture of dichloromethane and high-boiling point aromatic solvent oil, and the cleaning solvent is high-boiling point aromatic solvent oil.

[0008] Furthermore, the high-boiling point aromatic solvent oil is a mixture of hydrocarbons with more than ten carbon atoms, and the concentration of dichloromethane in the dissolving solvent is 70-80wt%.

[0009] Furthermore, in step S2, the mixture is rinsed with clean water until the material content in the water is less than 1 wt %.

[0010] Furthermore, in step S2, the immersion treatment time of the dissolving solvent and the cleaning solvent is 1 to 2 hours.

[0011] Furthermore, in step S3, the circulation flow rate of the dissolving solvent is 0.5 to 1 m 3 / h, the cycle time is 0.5~1h.

[0012] Furthermore, in step S4, the circulation flow rate of the cleaning solvent is 0.5 to 1 m 3 / h, cycle time is 10 to 15 minutes.

[0013] Furthermore, in step S5, the flushing time with clean water is 5 to 10 minutes.

[0014] The present invention also provides a cleaning system for implementing the above-mentioned cleaning method, comprising a dissolving solvent tank, a cleaning solvent tank and a circulation pump, wherein the inlet of the circulation pump is connected to the dissolving solvent tank and the cleaning solvent tank, the outlet of the circulation pump is connected to one end of the material pipeline of the shell and tube heat exchanger, and the other end of the material pipeline of the shell and tube heat exchanger is connected to the dissolving solvent tank and the cleaning solvent tank.

[0015] Furthermore, two valves are installed at both ends of the material pipeline of the shell and tube heat exchanger.

[0016] The beneficial effects of the present invention are as follows: the present invention adopts on-site cleaning of the heat exchanger, firstly uses a dissolving solvent to soak and dissolve the adhesives, and then uses a cleaning solvent to soak and clean the dissolving solvent and the adhesives, thereby removing most of the adhesives, and then uses the dissolving solvent to dissolve in a cycle, and the cleaning solvent to clean in a cycle in sequence, so as to completely remove the adhesives, and finally uses the cleaning solvent to wash away the residual cleaning agent. The present invention can effectively clean the adhesives in the shell and tube heat exchanger with less manpower, restore the heat exchange efficiency of the heat exchanger, and the content of the residual agent is extremely low, which does not affect the subsequent use, solves the problem of disassembly equipment in traditional physical cleaning, and provides great help for stable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a cleaning system according to an embodiment of the present invention.

[0018] Description of reference numerals: 1. Circulation pump; 2. Dissolving solvent tank; 3. Clean the solvent tank; 4. Shell and tube heat exchanger; 5. Valve. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0020] Unless otherwise specified, the raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial sources or by existing known methods; unless otherwise specified, the methods used in the examples and comparative examples of the present invention are methods known to those skilled in the art. Among them: D80 high boiling point aromatic solvent oil was purchased from Shanghai Nanmu Chemical Co., Ltd., model D80, with a saturated hydrocarbon content of more than 99%; The shell and tube heat exchangers cleaned below are all used in the working conditions where surfactants (common surfactants such as sodium dodecylbenzene sulfonate, benzalkonium chloride (Chlorhexidine), benzalkonium bromide (Chlorhexidine), benzalkonium chloride, etc.) are present in the etching waste liquid system (mainly containing ammonium fluoride, hydrofluoric acid and a small amount of organic impurities). The shell and tube heat exchangers that are used for a long time produce adhesives, resulting in poor heat exchange efficiency.

[0021] Example 1 Cleaning of adhesives in tube heat exchangers The cleaning steps are as follows: S1: Preparation of cleaning agent Prepare dissolving solvent and cleaning solvent; The dissolving solvent is a mixture of dichloromethane and D80 high-boiling-point aromatic solvent oil, and the concentration of dichloromethane is 70wt%; The cleaning solvent is D80 high boiling point aromatic solvent oil; S2: Soaking and dissolving The material pipeline of the shell-and-tube heat exchanger is first flushed with clean water until the material content in the water is 0.5wt%, then the clean water is drained and filled with a dissolving solvent and soaked for 1 hour, then the dissolving solvent is drained, and then filled with a cleaning solvent and soaked for 1 hour, and finally the cleaning solvent is drained; S3: Cycle Dissolution The material pipeline of the shell and tube heat exchanger is circulated and dissolved using a dissolving solvent, and the circulating flow rate of the dissolving solvent is 0.5m 3 / h, the circulation time is 1h, after which the dissolved solvent is discharged; S4: Circulation cleaning Use cleaning solvent to circulate and clean the material pipeline of the shell and tube heat exchanger. The circulation flow rate of the cleaning solvent is 0.5m 3 / h, the cycle time is 15min, after which the cleaning solvent is discharged; S5: Clean water Rinse the material pipeline of the shell and tube heat exchanger with clean water for 5 minutes, and then blow it dry with air.

[0022] Example 2 Cleaning of adhesives in tube heat exchangers The cleaning steps are as follows: S1: Preparation of cleaning agent Prepare dissolving solvent and cleaning solvent; The dissolving solvent is a mixture of dichloromethane and D80 high boiling point aromatic solvent oil, and the concentration of dichloromethane is 75wt%; The cleaning solvent is D80 high boiling point aromatic solvent oil; S2: Soaking and dissolving The material pipeline of the shell-and-tube heat exchanger is first flushed with clean water until the material content in the water is 0.7wt%, then the clean water is drained and filled with a dissolving solvent and soaked for 1.5 hours, then the dissolving solvent is drained, and then filled with a cleaning solvent and soaked for 1.5 hours, and finally the cleaning solvent is drained; S3: Cycle Dissolution The dissolving solvent is used to circulate and dissolve the material pipeline of the shell and tube heat exchanger. The circulating flow rate of the dissolving solvent is 0.7m 3 / h, the circulation time is 0.8h, after which the dissolved solvent is discharged; S4: Circulation cleaning The material pipeline of the shell and tube heat exchanger is circulated and cleaned with a cleaning solvent. The circulation flow rate of the cleaning solvent is 0.7m 3 / h, the cycle time is 12min, after which the cleaning solvent is discharged; S5: Clean water Rinse the material pipeline of the shell and tube heat exchanger with clean water for 8 minutes and then blow it dry with air.

[0023] Example 3 Cleaning of adhesives in tube heat exchangers The cleaning steps are as follows: S1: Preparation of cleaning agent Prepare dissolving solvent and cleaning solvent; The dissolving solvent is a mixture of dichloromethane and D80 high boiling point aromatic solvent oil, and the concentration of dichloromethane is 80wt%; The cleaning solvent is D80 high boiling point aromatic solvent oil; S2: Soaking and dissolving The material pipeline of the shell-and-tube heat exchanger is first rinsed with clean water until the material content in the water is 0.2wt%, then the clean water is drained and filled with a dissolving solvent and soaked for 2h, then the dissolving solvent is drained, and then filled with a cleaning solvent and soaked for 2h, and finally the cleaning solvent is drained; S3: Cycle Dissolution Use the dissolving solvent to circulate and dissolve the material pipeline of the shell and tube heat exchanger. The circulating flow rate of the dissolving solvent is 1m 3 / h, the circulation time is 0.5h, after which the dissolved solvent is discharged; S4: Circulation cleaning Use cleaning solvent to circulate and clean the material pipeline of the shell and tube heat exchanger. The circulation flow rate of the cleaning solvent is 1m 3 / h, the cycle time is 10min, after which the cleaning solvent is discharged; S5: Clean water Rinse the material pipeline of the shell and tube heat exchanger with clean water for 10 minutes, and then blow it dry with air.

[0024] Comparative Example 1 In this comparative example, the shell and tube heat exchanger under the same working condition is cleaned according to the method of Example 2, except that the dissolving solvent is pure dichloromethane.

[0025] Comparative Example 2 In this comparative example, the shell and tube heat exchanger under the same working condition is cleaned according to the method of Example 2, except that the immersion cleaning with the cleaning solvent in step S2 and step S4 are eliminated.

[0026] Comparative Example 3 In this comparative example, the shell and tube heat exchanger under the same working condition is cleaned according to the method of Example 2, except that the immersion cleaning with the dissolving solvent in step S2 is eliminated and step S3 is eliminated.

[0027] Comparative Example 4 In this comparative example, the shell and tube heat exchanger under the same working condition is cleaned according to the method of Example 2, except that step S5 is eliminated.

[0028] Experimental example Cleaning effect verification The steam supply flow rate required to achieve the same temperature rise was measured for the shell and tube heat exchangers cleaned in the above embodiment and comparative example before and after cleaning, and the results are shown in Table 1 below: Table 1 Verification of cleaning agent residual effect Clean water was passed into the cleaned shell and tube heat exchanger for 30 minutes, then the clean water was drained and the COD value was tested. The results are shown in Table 2 below: Table 2 It can be seen from the above results that the present invention can effectively remove heat exchanger adhesives, restore the heat exchange efficiency of the heat exchanger, and has little organic residue, which does not affect subsequent use. However, in Comparative Example 1, the D80 high-boiling point aromatic solvent oil in the dissolving solvent is omitted, which will lead to an increase in the final organic residue and is not conducive to subsequent production. In Comparative Example 2, after omitting the use of the cleaning solvent, more organic residues will be left after cleaning, and the cleaning effect will also be affected. In Comparative Example 3, after omitting the use of the dissolving solvent, the cleaning effect of the adhesives is not obvious. In Comparative Example 4, the final clean water rinse is omitted, resulting in reagent residues.

[0029] Example 4 This embodiment provides a cleaning system for implementing the above cleaning method, including a circulation pump 1, a dissolving solvent tank 2, and a cleaning solvent tank 3, wherein the inlet of the circulation pump 1 is connected to the dissolving solvent tank 2 and the cleaning solvent tank 3, the outlet of the circulation pump 1 is connected to one end of the material pipeline of the tube-in-tube heat exchanger 4 (two tube-in-tube heat exchangers are shown in the figure so that cleaning can be performed simultaneously), and the other end of the material pipeline of the tube-in-tube heat exchanger 4 is connected to the dissolving solvent tank 2 and the cleaning solvent tank 3. Two valves 5 are installed at both ends of the material pipeline of the tube-in-tube heat exchanger 4, respectively, for closing the material pipeline during immersion cleaning.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cleaning method for removing adhesives from a shell and tube heat exchanger, characterized in that: The following steps are involved: S1: Preparation of cleaning agent preparing a dissolving solvent for dissolving the stickies and a cleaning solvent for cleaning the dissolving solvent and the stickies; S2: Soaking and dissolving The material pipeline of the shell and tube heat exchanger is first flushed with clean water, then emptied of the clean water, filled with a dissolving solvent for soaking, then the dissolving solvent is drained, then filled with a cleaning solvent for soaking, and finally the cleaning solvent is drained; S3: Cycle Dissolution Using a dissolving solvent to circulate and dissolve the material pipeline of the shell and tube heat exchanger, and then discharging the dissolving solvent; S4: Circulation cleaning Use cleaning solvent to circulate and clean the material pipeline of the shell and tube heat exchanger, and then discharge the cleaning solvent; S5: Clean water Rinse the material lines of the shell and tube heat exchanger with clean water and then blow dry with air.

2. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, characterized in that: In step S1, the dissolving solvent is a mixture of dichloromethane and high-boiling point aromatic solvent oil, and the cleaning solvent is high-boiling point aromatic solvent oil.

3. The cleaning method for removing adhesives from a shell-and-tube heat exchanger according to claim 2, characterized in that: The high boiling point aromatic solvent oil is a mixture of hydrocarbons with more than ten carbon atoms, and the concentration of dichloromethane in the dissolving solvent is 70-80wt%.

4. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, 2 or 3, characterized in that: In step S2, the water is rinsed until the material content in the water is less than 1 wt%.

5. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, 2 or 3, characterized in that: In step S2, the immersion treatment time of the dissolving solvent and the cleaning solvent is 1 to 2 hours.

6. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, 2 or 3, characterized in that: In step S3, the circulation flow rate of the dissolving solvent is 0.5 to 1 m 3 / h, the cycle time is 0.5~1h.

7. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, 2 or 3, characterized in that: In step S4, the circulation flow rate of the cleaning solvent is 0.5 to 1 m 3 / h, cycle time is 10 to 15 minutes.

8. The cleaning method for removing adhesives from a shell and tube heat exchanger according to claim 1, 2 or 3, characterized in that: In step S5, the clean water flushing time is 5 to 10 minutes.

9. A cleaning system for implementing the cleaning method according to any one of claims 1 to 8, characterized in that: It includes a dissolving solvent tank, a cleaning solvent tank and a circulation pump, wherein the inlet of the circulation pump is connected to the dissolving solvent tank and the cleaning solvent tank, the outlet of the circulation pump is connected to one end of the material pipeline of the shell and tube heat exchanger, and the other end of the material pipeline of the shell and tube heat exchanger is connected to the dissolving solvent tank and the cleaning solvent tank.

10. The cleaning system according to claim 9, characterized in that: Two valves are installed at both ends of the material pipeline of the shell and tube heat exchanger.

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