JP6464377B2 - Method for dissolving polymer of carbonyl compound formed in basic washing of hydrocarbon cracking process - Google Patents

Description

  The present disclosure relates to a method for dissolving a polymer of a carbonyl compound produced in a basic washing of a hydrocarbon cracking process and a composition used therefor.

BACKGROUND ART Petrochemical products such as ethylene and propylene are produced by using hydrocarbons such as ethane, propane, butane, naphtha, light oil or a mixture thereof as a raw material and thermally decomposing them. The gas generated by this thermal decomposition contains acidic gases such as CO ₂ and H ₂ S. Since these cause corrosion and catalyst poisoning, they are removed by basic cleaning.
In the above thermal decomposition, for example, a carbonyl compound such as acetaldehyde is formed. This carbonyl compound such as acetaldehyde undergoes aldol condensation in the presence of a basic substance, and the formed polymer is known as one of the causative substances of soil in the hydrocarbon decomposition process.
For this reason, the method of suppressing the superposition | polymerization of a carbonyl compound and preventing the contamination | pollution | contamination of a hydrocarbon decomposition process is proposed (for example, patent documents 1-3).

Patent Document 1 uses an inorganic salt such as dithionite and 6-aminocaproic acid to suppress polymerization of components contained in the feed stream of the caustic cleaning unit system during the hydrocarbon cracking process and dissolve deposits A method is disclosed.
Patent Document 2 discloses a method of suppressing polymerization of a carbonyl compound in an operation of a basic cleaning apparatus in a hydrocarbon cracking process using α-amino acid or the like.
U.S. Patent No. 6,057,031 discloses basic washing of hydrocarbons in the presence of hydroxylamine.

JP 2005-530903 A JP-T-2004-513213 JP-A-62-87530

  Accordingly, the present disclosure provides, in one or a plurality of embodiments, a method capable of dissolving a polymer of a carbonyl compound generated in a basic cleaning of a hydrocarbon cracking process.

  The present disclosure, in one or more embodiments, is a method for dissolving a polymer of a carbonyl compound produced in a basic washing of a hydrocarbon cracking process, wherein the polymer is contacted with hydroxylamine or a salt thereof. A dissolution method comprising:

  In one or a plurality of embodiments, the present disclosure is a composition for dissolving a polymer of a carbonyl compound generated in a basic washing of a hydrocarbon cracking process, and includes hydroxylamine or a salt thereof as an active ingredient , Relating to the composition.

  In one or a plurality of embodiments, the present disclosure is a method for preventing fouling in an ethylene production plant, the ethylene production plant including a basic cleaning step of a hydrocarbon cracking process, wherein hydroxylamine or a salt thereof is added to the base. The present invention relates to a method for preventing contamination, which includes adding to a cleaning waste liquid discharged from a cleaning apparatus in which sexual cleaning is performed.

  In one or a plurality of embodiments, the present disclosure can dissolve a polymer of a carbonyl compound produced in a basic washing of a hydrocarbon cracking process.

FIG. 1 is a schematic view showing an example of a basic cleaning and waste liquid treatment process in an ethylene plant. FIG. 2A is a graph showing an example of the result of a confirmation test with an actual machine, and is an example of the number of cleanings of the pH meter electrode. FIG. 2B is a graph showing an example of a result of a confirmation test using an actual machine, and a graph showing a deposition rate of a deposit (polymer). FIG. 2C is a graph showing an example of a result of a confirmation test using an actual machine, and is a graph showing the number of times the pH meter electrode is cleaned.

FIG. 1 shows an example of basic cleaning in an ethylene plant and the flow of waste liquid discharged thereby. As shown in FIG. 1, a gas obtained by pyrolyzing a raw material such as naphtha or ethane is introduced into the cleaning tower 1 from the lower part of the cleaning tower 1 (a in FIG. 1). The gas introduced into the cleaning tower 1 is removed in the cleaning tower 1 with acidic cleaning liquid such as caustic soda (CO ₂ and H ₂ S, etc.) and discharged from the upper part of the cleaning tower 1 to a compressor and the like. (B in FIG. 1). On the other hand, the waste liquid in the washing tower 1 is discharged from the lower part of the washing tower 1 and is collected in the tank 4 through the treatment in the waste alkali sedimentation tank drum 2 and the red oil skimming drum 3. Thereafter, the gas is supplied to the tower 5, and the generated gas is discharged from the upper part of the tower 5, and the waste liquid is discharged from the lower part of the tower 5 and collected in the sedimentation tank 7 through the strainer 6 and the pump. In this step, there is a problem that the polymer of the carbonyl compound contained in the waste liquid discharged from the cleaning tower 1 is accumulated in the tank 4, the tower 5, the strainer 6, the sedimentation tank 7, or the like.

  The present disclosure is based on the finding that by using hydroxylamine or a salt thereof, a polymer of the carbonyl compound produced in the basic washing of the hydrocarbon cracking process can be dissolved. In this disclosure, by adding hydroxylamine or a salt thereof to the waste liquid discharged from the basic cleaning, the polymer of the carbonyl compound generated in the basic cleaning of the hydrocarbon decomposition process can be dissolved, and their deposition is suppressed. Or based on the knowledge that it can be prevented.

  According to the present disclosure, in one or a plurality of embodiments, by using hydroxylamine or a salt thereof, the polymer of the carbonyl compound generated in the basic washing of the hydrocarbon decomposition process can be dissolved. . Furthermore, in one or a plurality of embodiments, according to the present disclosure, a polymer of a carbonyl compound generated in a basic cleaning of a hydrocarbon cracking process can be dissolved, and thus a polymer of a carbonyl compound is generated in a basic cleaning. Even in such a case, it is possible to effectively suppress or prevent soiling in the ethylene production plant.

[Method of dissolving polymer of carbonyl compound]
The present disclosure, in one or more embodiments, is a method for dissolving a polymer of a carbonyl compound produced in a basic washing of a hydrocarbon cracking process, wherein the polymer is contacted with hydroxylamine or a salt thereof. A dissolution method comprising:

  In the present disclosure, examples of the hydrocarbon cracking process include naphtha cracking, etantac racking, and the like in one or a plurality of embodiments. In the present disclosure, the raw material for the hydrocarbon cracking process includes naphtha or ethane in one or more embodiments.

  In the present disclosure, the polymer of the carbonyl compound generated in the basic washing of the hydrocarbon cracking process includes, in one or more embodiments, an aldol polymer generated by aldol condensation of acetaldehyde or a condensation polymer called red oil. It is done.

  In the present disclosure, examples of the basic washing tower include a caustic soda washing tower and an amine washing tower in one or a plurality of embodiments.

  In one or a plurality of embodiments, the present disclosure adds hydroxylamine or a salt thereof to a cleaning waste liquid discharged from a cleaning apparatus in which basic cleaning is performed, from the viewpoint that a polymer of a carbonyl compound can be efficiently dissolved. including. In one or more embodiments, the present disclosure includes introducing hydroxylamine or a salt thereof downstream from the bottom of the basic wash tower.

  Examples of the hydroxylamine salt include phosphate, sulfate, sulfite, hydrochloride, nitrate, acetate, and propionate in one or more embodiments. From the viewpoint of the solubility of the aldol polymer, the hydroxylamine salt is preferably sulfate or hydrochloride, more preferably hydroxylamine sulfate. In one or more embodiments, the present disclosure includes using as an active ingredient at least one selected from the group consisting of hydroxylamine sulfate, hydroxylamine hydrochloride, and hydroxylamine, and combinations thereof.

  In the present disclosure, the concentration of hydroxylamine or a salt thereof added is not particularly limited, and cleaning discharged from the basic cleaning device is effective in that the aldol polymer is dissolved and removed to effectively suppress or prevent soiling in the hydrocarbon decomposition process. The amount is 1 mg / L or more, preferably 2 mg / L or more with respect to the amount of waste liquid, and is 100 mg / L or less, preferably 50 mg / L or less, from the viewpoint of economy required for dissolving the aldol polymer.

  In the present disclosure, the frequency of addition of hydroxylamine or a salt thereof is not particularly limited, and the number of additions and the addition time can be appropriately selected according to the degree of soiling. In one or a plurality of embodiments, the addition of hydroxylamine or a salt thereof may be added continuously or intermittently, and the number of additions and the addition time can be selected as appropriate, and the aldol polymer is dissolved and removed. However, it is sufficient that the contamination in the hydrocarbon cracking process can be efficiently suppressed or prevented.

  In the present disclosure, hydroxylamine or a salt thereof can be used in the form of a solid, powder or aqueous solution in one or more embodiments. When used as an aqueous solution, the concentration of hydroxylamine or a salt thereof in the aqueous solution is not particularly limited. From the viewpoint of safety of the composition, stability, cost, and / or ease of addition, 5 It contains 50% by weight or less or 40% by weight or less.

[Composition for dissolving polymer of carbonyl compound]
In one or a plurality of embodiments, the present disclosure is a composition for dissolving a polymer of a carbonyl compound generated in a basic washing of a hydrocarbon cracking process, and includes hydroxylamine or a salt thereof as an active ingredient Relates to the composition. According to the composition of the present disclosure, in one or a plurality of embodiments, it is possible to efficiently dissolve a polymer of a carbonyl compound produced in a basic cleaning of a hydrocarbon cracking process, and preferably a fouling in an ethylene production plant. Can be efficiently prevented. The composition of this indication can be used for the dissolution method of this indication in one or some embodiment.

  In the composition of the present disclosure, the hydroxylamine or a salt thereof is as described above. In one or more embodiments, the composition of the present disclosure contains, as an active ingredient, at least one selected from the group consisting of hydroxylamine sulfate, hydroxylamine hydrochloride, and hydroxylamine and combinations thereof.

  The composition of the present disclosure may be in the form of a solid, powder or aqueous solution in one or more embodiments. When the composition is solid or powder, it may be dissolved in advance to form an aqueous solution, or may be added as it is. Hydroxylamine or a salt thereof can be added in the form of an aqueous solution at a concentration depending on the solubility in water, but 5% by weight from the viewpoint of the safety, stability, cost and / or ease of addition of the composition % Or 10% by weight or more, preferably 50% by weight or less or 40% by weight or less, but is not particularly limited.

[Stain prevention method]
In one or a plurality of embodiments, the present disclosure is a method for preventing fouling in an ethylene production plant, the ethylene production plant including a basic cleaning step of a hydrocarbon cracking process, wherein hydroxylamine or a salt thereof is added to the basic production step. The present invention relates to a stain prevention method including adding to a cleaning waste liquid discharged from a cleaning apparatus in which cleaning is performed.
In one or a plurality of embodiments, the dirt prevention method of the present disclosure includes performing the dissolution method of the present disclosure.

The present disclosure may relate to one or more of the following embodiments;
[1] A method for dissolving a polymer of a carbonyl compound produced in basic washing of a hydrocarbon cracking process,
A dissolution method comprising contacting the polymer with hydroxylamine or a salt thereof.
[2] The dissolution method according to [1], comprising adding the hydroxylamine or a salt thereof to a cleaning waste liquid discharged from a cleaning apparatus in which the basic cleaning is performed.
[3] The dissolution method according to [1] or [2], wherein the hydroxylamine or a salt thereof is selected from the group consisting of hydroxylamine sulfate, hydroxylamine hydrochloride, hydroxylamine, and combinations thereof.
[4] A composition for dissolving a polymer of a carbonyl compound produced in basic washing of a hydrocarbon cracking process,
A composition comprising hydroxylamine or a salt thereof as an active ingredient.
[5] A method for preventing contamination in an ethylene production plant,
The ethylene production plant includes a basic cleaning step of a hydrocarbon cracking process;
A method for preventing soiling, comprising adding hydroxylamine or a salt thereof to a cleaning waste liquid discharged from a cleaning apparatus in which the basic cleaning is performed.

  Hereinafter, the present disclosure will be further described using examples. However, the present disclosure is not construed as being limited to the following examples.

[Confirmation of dissolution effect of aldol condensate]
In order to clarify the effect of dissolving an aldol condensate of hydroxylamine or a salt thereof, a test solution in which an aldol polymer was precipitated was prepared by a desktop test and evaluated using the test solution. First, 30 mL of a 5N aqueous sodium hydroxide solution was collected in a beaker, and 45 mL of pure water was added and stirred. Next, 5 g of vinyl acetate was added while stirring, and stirring was continued until the exotherm was completed, thereby causing aldol condensation to prepare Test Solution A containing an aldol polymer.
Separately, the chemicals shown in Table 1 below were added to Spitz with a 10 mL lid so as to have the addition amount shown in Table 1, dissolved in 5 mL of pure water, and then 5 mL of Test Solution A was dispensed and shaken vigorously 10 times. Allowed to stand for 10 minutes. Thereafter, turbidity (800 nm) was measured. The results are shown in Table 1 below.
Blank dispensed 5 mL of test solution A into 5 mL of pure water containing no drug, and performed the same measurement as above.

  As shown in Table 1, by using hydroxylamine sulfate, hydroxylamine hydrochloride or hydroxylamine, compared to using a mixture of sodium dithionite and 6-aminocaproic acid, sodium glycine, or diethylhydroxylamine. The aldol polymer in the test solution could be dissolved. Further, when the appearance was visually observed, it was confirmed that all the comparative examples were clouded, whereas in the examples, the aldol polymer was dissolved.

[Confirmation test with actual machine]
Hydroxyl sulfate is connected to a portion (position indicated by arrow X in FIG. 1) connecting the caustic soda washing tower 1 of the ethylene plant shown in FIG. 1 and a tank 2 for collecting the washing waste liquid discharged from the bottom of the caustic soda washing tower 1. The case where the aqueous amine solution was continuously added to the washing waste liquid amount of 3.3 mg / L and the case where the hydroxylamine sulfate aqueous solution was not added were compared in 100 working days. The results are shown in FIGS. 2A and 2B. FIG. 2A is a graph showing the number of cleanings of the pH meter electrode to which the polymer arranged at the position indicated by A in FIG. 1 is likely to adhere, and FIG. 2B is the deposition of the deposit (polymer) in the settling tank 7 in FIG. It is a graph which shows a rate. The polymer deposition rate was determined by measurement with a surface thermometer utilizing the property that the surface temperature of the tank decreases due to the influence of the outside air temperature when the polymer is deposited. Further, it was confirmed by a qualitative test such as infrared spectroscopy and measurement of loss of ignition under 800 ° C. that the deposit was a polymer of a carbonyl compound.
On the other hand, a confirmation test was conducted in which 1.5 mg / L was continuously added for 20 days from the state in which the hydroxylamine sulfate aqueous solution was not added to the washing waste liquid amount, then was added for 15 days, and then 3.3 mg / L was continuously added. went. Evaluation was made only by the number of cleanings of the pH meter electrode, and the result is shown in FIG. 2C.

As shown in FIGS. 2A and 2B, after adding hydroxylamine sulfate, the amount of polymer adhering to the electrode of the pH meter was reduced, and the number of cleanings was greatly reduced from 56 to 4 times per week. The polymer deposition rate was also greatly reduced.
Further, as shown in FIG. 2C, even when the addition concentration was changed, the cleaning frequency, which was about 8 times a day when hydroxylamine sulfate was not added, became about 4 times after 1.5 mg / L was continuously added. Halved. Thereafter, the number of cleanings did not increase even after the addition was stopped for 15 days. Thereafter, when 3.3 mg / L was continuously added, the number of cleanings was reduced to about 2 times, and there was a day when cleaning was not necessary. This is probably because the polymer deposited in the system gradually dissolved due to the dissolution effect of hydroxylamine sulfate, which caused a time lag between the timing of addition and the decrease in the number of cleanings. This is a result of supporting.

Claims (4)

A method for dissolving a polymer of a carbonyl compound produced in a basic washing of a hydrocarbon cracking process, comprising:
A dissolution method comprising contacting the polymer with hydroxylamine or a salt thereof by adding hydroxylamine or a salt thereof to a washing waste liquid discharged from a washing apparatus in which the basic washing is performed . The hydroxylamine or its salt, hydroxylamine sulfate, hydroxylamine hydrochloride, and is selected from hydroxylamine and combinations thereof, dissolution process of claim 1. A composition for dissolving a polymer of a carbonyl compound produced in basic washing of a hydrocarbon cracking process,
A composition comprising hydroxylamine or a salt thereof as an active ingredient. A method for preventing contamination in an ethylene production plant,
The ethylene production plant includes a basic cleaning step of a hydrocarbon cracking process;
A method for preventing soiling, comprising adding hydroxylamine or a salt thereof to a cleaning waste liquid discharged from a cleaning apparatus in which the basic cleaning is performed.

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