A stainless steel pipe cleaning agent for thermal desorption and a cleaning method thereof

Abstract

The present invention discloses a stainless steel pipe detergent for thermal desorption and a cleaning method thereof, comprising the following components: deionized water, ethanol, sodium hydroxide, sodium carbonate, sodium citrate and sodium dodecylbenzene sulfonate; the content of each component in 1 liter of deionized water is: sodium hydroxide 40.5-49.5g, sodium carbonate 13.5-16.5g, sodium citrate 27-33g, sodium dodecylbenzene sulfonate 2.7-3.3g, ethanol 180-220ml. The present invention cleans the oil stains on the surface of stainless steel by alkali solution, and adds a surfactant to dissolve long-chain organic macromolecules in an aqueous solution; with subsequent ethanol ultrasound, dilute hydrochloric acid ultrasound and sodium carbonate solution ultrasound treatment steps, the problem of rust spots occurring after the stainless steel pipe is cleaned can be eliminated, and finally a clean stainless steel pipe with low organic residues and metallic luster is obtained. The present invention has a simple process, low requirements for materials, and is easy to industrialize.

Description

Technical Field

[0001] The invention relates to a detergent and a cleaning method thereof, in particular to a stainless steel pipe detergent for thermal desorption and a cleaning method thereof. Background Art

[0002] Stainless steel has good corrosion resistance and thermal conductivity, and is used in various fields. Stainless steel will produce oil and rust stains during the process of being processed into pipe fittings. After the existing technology cleans stainless steel pipe fittings, the use effect is not ideal and the finish is poor. Many researchers have optimized the cleaning process of stainless steel. For example, the patent document CN106521525A, entitled "A stainless steel surface treatment agent and its preparation method and use method", uses a series of surfactants such as nitric acid, hydrofluoric acid, triethylene glycol, urotropine and other surface treatment agents and fatty acid esters to treat stainless steel materials once. The patent document CN105839119B, entitled "Stainless steel cleaning agent material composition, stainless steel cleaning agent and its preparation method and application", uses nitric acid, hydrofluoric acid, lauric acid diethanolamide, oleic acid triethanolamine, benzotriazole, carboxymethyl cellulose, citric acid and water mixed surface treatment agent to clean stainless steel materials.

[0003] The existing technology can clean the stains on the surface of stainless steel relatively cleanly, but it is still unable to clean the inside of the pipe fittings. In particular, the stainless steel pipes used in thermal desorption have high requirements for the organic residue on the surface of the pipe fittings. At present, after the cleaning of the pipe fittings, there are still a lot of long-chain organic residues in the thermal desorption test. Figure 2 This may be because the existing stainless steel cleaning agents use a large amount of long-chain organic detergents, so how to clean the stainless steel pipe to obtain a cleaning effect with low organic residue and a smooth and clear surface is a technical problem that needs to be solved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a stainless steel pipe detergent for thermal desorption and a cleaning method thereof, which can obtain stainless steel pipes with low organic residue, greatly reduce the organic residue of the thermal desorption tube itself, and reduce the aging time of the thermal desorption tube.

[0005] The technical solution adopted by the present invention to solve the above technical problems is to provide a stainless steel pipe cleaning agent for thermal desorption, which comprises the following components: deionized water, ethanol, sodium hydroxide, sodium carbonate, sodium citrate and sodium dodecylbenzene sulfonate.

[0006] The above-mentioned stainless steel pipe cleaning agent for thermal desorption, wherein the contents of each component per 1 liter of deionized water are: 40.5-49.5 g of sodium hydroxide, 13.5-16.5 g of sodium carbonate, 27-33 g of sodium citrate, 2.7-3.3 g of sodium dodecylbenzene sulfonate, and 180-220 ml of ethanol.

[0007] The above-mentioned stainless steel pipe cleaning agent for thermal desorption, wherein the contents of each component per 1 liter of deionized water are: 45g of sodium hydroxide, 15g of sodium carbonate, 30g of sodium citrate, 3g of sodium dodecylbenzene sulfonate, and 200ml of ethanol.

[0008] In order to solve the above technical problems, the present invention also provides a method for cleaning stainless steel pipe fittings for thermal desorption, comprising the following steps: S1) completely immersing the stainless steel pipe fittings in the above detergent, controlling the temperature to 60-70°C, and treating the pipe fittings for 5 hours; S2) taking out the cleaned stainless steel pipe fittings and placing them in ethanol, ultrasonically treating the pipe fittings for 30 minutes to clean the trace residual organic matter on the surface of the steel pipe; S3) placing the stainless steel pipe fittings in a dilute hydrochloric acid solution, ultrasonically treating the pipe fittings for 30 minutes, and passivating the surface of the steel pipe to prevent the appearance of rust stains; S4) placing the stainless steel pipe fittings in a sodium carbonate solution, ultrasonically treating the pipe fittings for 30 minutes to neutralize the hydrochloric acid on the surface of the steel pipe; S5) completely immersing the stainless steel pipe fittings in heated deionized water, ultrasonically treating the pipe fittings for 15 minutes; S6) repeating step S5) for 3 times to thoroughly wash away the residual sodium carbonate; S7) placing the stainless steel pipe fittings in an oven, controlling the temperature to 50-60°C, and treating the pipe fittings for 8-12 hours.

[0009] In the above-mentioned method for cleaning stainless steel pipes for thermal desorption, the preparation process of the detergent is as follows: first, sodium hydroxide, sodium carbonate and sodium citrate are dissolved in deionized water according to predetermined concentrations, and the dissolution is completely mixed to form an aqueous solution; then sodium dodecylbenzene sulfonate is added to ethanol and completely dissolved to form an alcohol solution; finally, the aqueous solution and the alcohol solution are mixed evenly to obtain a stainless steel pipe detergent for thermal desorption.

[0010] The above-mentioned cleaning method for stainless steel pipes for thermal desorption, wherein, after the sodium hydroxide, sodium carbonate and sodium citrate are added to deionized water, the treatment method is to continuously stir the deionized water with a glass plate during the addition of the aqueous solution, and after all the substances are added, the container containing the aqueous solution is placed in an ultrasonic cleaner for ultrasonic dissolution; then sodium dodecylbenzene sulfonate is added to ethanol, and finally the container containing the alcohol solution is placed in an ultrasonic cleaner for dissolution.

[0011] In the above-mentioned method for cleaning stainless steel pipes for thermal desorption, the concentration of the dilute hydrochloric acid solution is 10 ml / L, and the concentration of the sodium carbonate solution is 10 g / L.

[0012] The above-mentioned thermal desorption cleaning method for stainless steel pipes also includes the following detection steps: first aging the steel pipe, and then using thermal desorption combined with gas chromatography-mass spectrometry to detect organic residues in the cleaned steel pipe.

[0013] Compared with the prior art, the present invention has the following beneficial effects: the stainless steel pipe cleaning agent for thermal desorption and the cleaning method provided by the present invention clean the oil stains on the surface of the stainless steel with alkali solution, and add a surfactant to dissolve the long-chain organic macromolecules in the aqueous solution; with the subsequent ethanol ultrasonic treatment, dilute hydrochloric acid ultrasonic treatment and sodium carbonate solution ultrasonic treatment steps, the rust spots that appear after the stainless steel pipe is cleaned can be eliminated, and finally a clean stainless steel pipe with a metallic luster is obtained. The present invention has a simple process, low requirements for materials, and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the cleaning process of stainless steel pipes for thermal desorption of the present invention.

[0015] Figure 2 GC-MS chromatogram of the steel tube obtained after general cleaning steps.

[0016] Figure 3 The GC-MS chromatogram of the steel pipe after washing of the preferred stainless steel pipe detergent of the present invention.

[0017] Figure 4 The GC-MS chromatogram of the steel pipe after washing with the preferred second stainless steel pipe cleaning agent of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] The stainless steel pipe cleaning agent for thermal desorption provided by the present invention comprises deionized water, ethanol, sodium hydroxide, sodium carbonate, sodium citrate, and sodium dodecylbenzene sulfonate; the preferred preparation ratio of each substance is as follows:

[0020] The concentrations of the substances contained in every 1 liter of deionized water are: sodium hydroxide 40.5-49.5g / L, sodium carbonate 13.5-16.5g / L, sodium citrate 27-33g / L, sodium dodecylbenzene sulfonate 2.7-3.3g / L, and ethanol 180-220ml / L. The steps for preparing the above-mentioned detergent are: dissolving sodium hydroxide, sodium carbonate and sodium citrate in deionized water, and mixing them completely and evenly to form an aqueous solution. Sodium dodecylbenzene sulfonate is added to ethanol, and dissolved completely to form an alcohol solution; the aqueous solution and the alcohol solution are mixed evenly. The present invention cleverly selects the above-mentioned mixed components for steel pipe cleaning, so that the inner wall of the steel pipe can also be thoroughly cleaned, and uses thermal desorption combined with gas chromatography-mass spectrometry to detect organic residues in the cleaned steel pipe. The test results are as follows Figure 3 As shown. Within the retention time of 35min, Figure 2 The stainless steel tube obtained by the general cleaning method has many organic impurity peaks, and the peak intensity is also high, especially the peaks of long-chain organic substances at the retention time of about 30 minutes. However, the stainless steel tube cleaned by the preferred solution has only a few tiny impurity peaks with very small peak intensity before 35 minutes.

[0021] In order to further reduce the organic residue, the preferred preparation ratio of each substance is as follows:

[0022] The concentrations of each substance contained in 1 liter of deionized water are: 45g / L sodium hydroxide, 15g / L sodium carbonate, 30g / L sodium citrate, 3g / L sodium dodecylbenzene sulfonate, and 200ml / L ethanol. The steps for preparing the above-mentioned detergent are: weigh sodium hydroxide, sodium carbonate and sodium citrate according to the corresponding concentrations and dissolve them in deionized water, and mix them completely and evenly to form an aqueous solution. Add a corresponding amount of sodium dodecylbenzene sulfonate to ethanol and dissolve it completely to form an alcohol solution; mix the obtained aqueous solution and alcohol solution evenly to obtain the preferred stainless steel pipe detergent for thermal desorption. The cleaned steel pipe is then tested for organic residues using the thermal desorption-GC-MS method, and the test results are as follows. Figure 4 shown.

[0023] According to the preferred solution 2, the detergent was prepared and the clear stainless steel tube had no organic residue detected before 35 minutes. Figure 4 It can be seen that there is only a baseline, compared Figure 3 The trace amount of residue is obvious and the effect is better. The following implementation examples are described in detail the present invention. Among them, sodium hydroxide, sodium carbonate, sodium citrate, sodium dodecylbenzene sulfonate, ethanol, and hydrochloric acid are all commercially available conventional chemicals.

[0024] Example 1

[0025] (1) 121.5 g of sodium hydroxide, 40.5 g of sodium carbonate, 81 g of sodium citrate and 3 L of water were mixed and dissolved to obtain an aqueous solution;

[0026] (2) 8.1 g of sodium dodecylbenzene sulfonate and 540 ml of ethanol were mixed and dissolved to obtain an alcohol solution;

[0027] The aqueous solution and the alcohol solution are ultrasonically mixed to obtain a stainless steel detergent.

[0028] Example 2

[0029] (1) 148.5 g of sodium hydroxide, 49.5 g of sodium carbonate, 99 g of sodium citrate and 3 L of water were mixed and dissolved to obtain an aqueous solution;

[0030] (2) 9.9 g of sodium dodecylbenzene sulfonate and 660 ml of ethanol were mixed and dissolved to obtain an alcohol solution;

[0031] The aqueous solution and the alcohol solution are ultrasonically mixed to obtain a stainless steel detergent.

[0032] Example 3

[0033] (1) 135 g of sodium hydroxide, 45 g of sodium carbonate, 90 g of sodium citrate and 3 L of water were mixed and dissolved to obtain an aqueous solution;

[0034] (2) Mix 9 g of sodium dodecylbenzene sulfonate and 600 ml of ethanol and dissolve them to obtain an alcohol solution;

[0035] The aqueous solution and the alcohol solution are ultrasonically mixed to obtain a stainless steel detergent.

[0036] See also Figure 1 The preparation and cleaning method of the stainless steel cleaner described above is carried out according to the following steps:

[0037] After adding sodium hydroxide, sodium carbonate and sodium citrate to deionized water, the treatment method is to continuously stir the deionized water with a glass plate during the addition of the aqueous solution. After all the substances are added, the container containing the aqueous solution is placed in an ultrasonic cleaner for ultrasonic dissolution; then sodium dodecylbenzene sulfonate is added to ethanol, and the container containing the alcohol solution is placed in an ultrasonic cleaner for dissolution; dissolving separately can save the dissolution time of sodium carbonate and sodium citrate.

[0038] Place the thermal desorption stainless steel pipes into the prepared stainless steel detergent mixture to ensure that all pipes are immersed. The treatment temperature is 60-70°C and the treatment time is 5 hours.

[0039] After the stainless steel pipes were treated with stainless steel detergent, the detergent was drained and then placed in 3L ethanol and ultrasonically treated for 30 minutes to clean the trace residual organic matter on the surface of the steel pipes.

[0040] Pipette 30 ml of hydrochloric acid and add it to 3 L of deionized water to prepare a 10 ml / L dilute hydrochloric acid solution. Place the stainless steel pipe fittings that have been ultrasonicated with ethanol into the 10 ml / L dilute hydrochloric acid solution and ultrasonicate for 30 minutes to passivate the surface of the steel pipe to prevent the appearance of rust stains.

[0041] Weigh 30g of sodium carbonate and dissolve it in 3L of deionized water to prepare a 10g / L sodium carbonate solution. Put the stainless steel pipe treated with 10ml / L dilute hydrochloric acid into the 10g / L sodium carbonate solution and ultrasonically treat it for 30 minutes to neutralize the hydrochloric acid on the surface of the steel pipe.

[0042] Heat the deionized water to 60-70℃; put the stainless steel pipes treated with 10ml / L dilute hydrochloric acid into the heated deionized water, the deionized water needs to submerge the pipes, and ultrasonicate for 15 minutes. Repeat the operation of "putting the stainless steel pipes treated with 10ml / L dilute hydrochloric acid into the heated deionized water, the deionized water needs to submerge the pipes, and ultrasonicate for 15 minutes" 3 times; the repeated operation is to thoroughly wash away the sodium carbonate residue.

[0043] The stainless steel pipes that have been ultrasonically treated with heated deionized water are placed in an oven, the temperature is controlled at 50-60° C., and the treatment time is 8-12 hours.

[0044] The cleaned steel pipe was subjected to thermal desorption-GC-MS detection.

[0045] Gas chromatograph, Trace 1300;

[0046] Mass spectrometer: ISQ QD single quadrupole mass spectrometer;

[0047] Thermal desorption device: MARKES TD100-XR;

[0048] The chromatographic column is CD-1MS, 60m×0.32mm×1.0μm;

[0049] 1) The aging procedure is as follows:

[0050]

[0051]

[0052] 2) Thermal desorber conditions

[0053]

[0054] 3) Gas chromatograph reference conditions

[0055] Column flow rate: 1.5ml / min;

[0056] Heating program:

[0057] Initial temperature 35°C, maintain for 5 min;

[0058] Raise the temperature to 140°C at 6°C / min and hold for 2 min;

[0059] Raise the temperature to 220°C at 15°C / min and maintain for 3 min.

[0060] Mass spectrometry conditions

[0061] Scanning mode: full scan;

[0062] Scan range: 4.5min, 33-180amu,

[0063] 6min,33-270amu

[0064] Transmission line temperature: 300°C;

[0065] Ion source temperature: 300°C.

[0066] The above cleaning process is characterized by removing oil stains on the surface of stainless steel pipe fittings, passivating stainless steel pipe fittings and preventing rust stains on the surface of stainless steel pipe fittings. This process is applied to the cleaning of stainless steel fittings related to thermal desorption analysis tubes, and the cleaning results are detected by mass spectrometry, which can ensure that the residual organic background of stainless steel pipes and related fittings is greatly reduced, which is beneficial to improving product performance and reducing aging time.

[0067] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A method for cleaning stainless steel pipes for thermal desorption, characterized in that: The steps include: S1) preparing a detergent comprising the following components: deionized water, ethanol, sodium hydroxide, sodium carbonate, sodium citrate and sodium dodecylbenzene sulfonate, wherein, for every liter of deionized water, the content of each component is: 45g of sodium hydroxide, 15g of sodium carbonate, 30g of sodium citrate, 3g of sodium dodecylbenzene sulfonate, and 200ml of ethanol; S2) completely immersing the stainless steel pipe in the detergent, controlling the temperature to 60-70° C., and treating for 5 hours; S3) taking out the cleaned stainless steel pipe fittings and placing them in ethanol for ultrasonic treatment for 30 minutes to clean the trace residual organic matter on the surface of the steel pipe; S4) placing the stainless steel pipe fittings in a dilute hydrochloric acid solution and subjecting them to ultrasonic treatment for 30 minutes to passivate the surface of the steel pipe to prevent the appearance of rust stains; the concentration of the dilute hydrochloric acid solution is 10 ml / L; S5) Place the stainless steel pipe in a sodium carbonate solution and perform ultrasonic treatment for 30 minutes to neutralize the hydrochloric acid on the surface of the steel pipe; S6) The stainless steel pipe is completely immersed in heated deionized water and ultrasonically treated for 15 minutes; S7) repeating step S6 three times to completely wash away the residual sodium carbonate; S8) Place the stainless steel pipe into an oven, control the temperature to 50-60°C, and process for 8-12 hours.

2. The method for cleaning a stainless steel pipe for thermal desorption according to claim 1, characterized in that: The preparation process of the detergent is as follows: Firstly, sodium hydroxide, sodium carbonate and sodium citrate are dissolved in deionized water according to a predetermined concentration, and the solution is completely mixed to form an aqueous solution; then sodium dodecylbenzene sulfonate is added to ethanol and completely dissolved to form an alcohol solution; finally, the aqueous solution and the alcohol solution are mixed to obtain a stainless steel pipe cleaning agent for thermal desorption.

3. The method for cleaning stainless steel pipes for thermal desorption according to claim 1, characterized in that: The concentration of the sodium carbonate solution is 10 g / L.

4. The method for cleaning a stainless steel pipe for thermal desorption according to claim 1, characterized in that: The method also includes the following detection steps: first aging the steel pipe, and then using thermal desorption combined with gas chromatography-mass spectrometry to detect organic residues in the cleaned steel pipe.

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