JP6933238B2 - How to eliminate the differential pressure in the distillation column - Google Patents

Description

The present invention relates to a method for relieving the differential pressure of a distillation column.

In the distillation column of distillation equipment such as petroleum refining process, petrochemical process or coal chemical process, pressure loss (hereinafter referred to as "differential pressure") is caused by the precipitation of salts typified by ammonium chloride, which obstructs the process flow. ) Has occurred, and the decrease in equipment usage efficiency has become a problem. In addition, there is a problem that severe local corrosion occurs in the equipment due to the absorption of the precipitated salt.
Under these circumstances, a sublimation operation method or a method of applying washing water to the inside of a tower is usually used as a method of suppressing the generation of differential pressure due to salt precipitation.
The sublimation operation method is an operation method in which the precipitated salt is sublimated by raising the temperature of the distillation column and discharged to the top system of the distillation column. By the sublimation operation, the precipitated salt can be quickly removed.
The washing water application method is a treatment method in which the washing water is supplied to the top reflux line of the distillation column, and the washing water is supplied to the place where the differential pressure is generated due to the precipitation of the salt to dissolve and remove the salt. .. By supplying wash water, the differential pressure can be eliminated in a short time.
For example, Non-Patent Document 1 describes a sublimation operation method in which a precipitated salt is sublimated by raising the temperature of the distillation column in a short period of time and discharged to the top system of the distillation column.
Further, for example, Patent Document 1 describes a method for distilling a hydrocarbon oil by introducing water into a distillation column in a distillation treatment of a hydrocarbon oil containing water-soluble salts.

Japanese Unexamined Patent Publication No. 2000-096067

GRACE DAVISION CATALAGRAM, ISSUE, 2010, No. 107, p. 34-39

However, when the sublimation operation method is temporarily applied, the boiling point range of the fraction (petroleum product base material) refined in the distillation column changes because the operation is performed in a temperature range higher than that of the normal operation. It may be out of the standard. In this case, in order to improve the yield, most of the fraction during the sublimation operation is repurified. Also, if applied permanently, the recovery rate of light components must be sacrificed. In any case, the result is a decrease in production efficiency.
Further, in the washing water application method, if the drain water used for dissolving the salt cannot be properly discharged, the differential pressure may be generated again due to the reprecipitation of the salt or the corrosion product. In addition, the progress of corrosion may shorten the life of the equipment itself.

The present invention has been made in view of such circumstances, and pressure loss (differential pressure) generated by salts generated from impurities in raw materials in a distillation facility so as not to adversely affect product quality and production efficiency. It is an object of the present invention to provide a method for eliminating the differential pressure that eliminates the above pressure during operation.

In order to solve the above problems, as a result of diligent research, the present inventors supplied a specific quaternary ammonium compound to a distillation facility and brought it into contact with the precipitated salt to make the salt a highly fluid neutralized salt. It was found that the problem can be solved by easily discharging it to the outside of the system.
The present invention has been completed based on such findings.

（式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭素数１〜４の炭化水素基を表し、ｎは１〜１０の整数を表す。）
（２）前記一般式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３が、それぞれ独立に、炭素数１〜３の炭化水素基であり、ｎが１〜４の整数である、上記（１）に記載の差圧解消方法。
（３）前記第４級アンモニウム化合物が、β−ヒドロキシエチルトリメチルアンモニウムハイドロオキサイドである、上記（１）又は（２）に記載の差圧解消方法。
（４）前記蒸留設備が、石油精製プロセス、石油化学プロセス、又は石炭化学プロセス用設備である、上記（１）〜（３）のいずれかに記載の差圧解消方法。
（５）前記蒸留設備内の蒸留塔と接触し得るプロセス流体に、前記一般式〔１〕で表される第４級アンモニウム化合物を含有させる、上記（１）〜（４）のいずれかに記載の差圧解消方法。
（６）蒸留設備における塩の析出に由来する差圧発生を解消する差圧解消剤であって、下記一般式〔１〕で表される第４級アンモニウム化合物を含有する、差圧解消剤。

（式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭素数１〜４の炭化水素基を表し、ｎは１〜１０の整数を表す。） That is, the disclosure of the present application relates to the following.
(1) A method for eliminating the generation of differential pressure due to salt precipitation in a distillation facility, wherein a quaternary ammonium compound represented by the following general formula [1] is used as a salt removing agent.

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10).
(2) In the general formula [1], R ¹ , R ² and R ³ are each independently a hydrocarbon group having 1 to 3 carbon atoms, and n is an integer of 1 to 4 above (1). ) Is the method for eliminating the differential pressure.
(3) The method for relieving the differential pressure according to (1) or (2) above, wherein the quaternary ammonium compound is β-hydroxyethyltrimethylammonium hydroxide.
(4) The method for relieving differential pressure according to any one of (1) to (3) above, wherein the distillation facility is a facility for a petroleum refining process, a petroleum chemical process, or a coal chemical process.
(5) The above-mentioned (1) to (4), wherein the process fluid that can come into contact with the distillation column in the distillation facility contains a quaternary ammonium compound represented by the general formula [1]. How to eliminate the differential pressure.
(6) A differential pressure relieving agent that eliminates the generation of differential pressure due to salt precipitation in a distillation facility and contains a quaternary ammonium compound represented by the following general formula [1].

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10).

According to the present invention, there is a method for eliminating the pressure loss (differential pressure) generated by the salt generated from impurities in the raw material in the distillation facility during operation so as not to adversely affect the quality and production efficiency of the product. Can be provided.

It is a flow chart for demonstrating the method of eliminating the differential pressure of the distillation equipment which concerns on one Embodiment of this invention. It is a block diagram of the desk test apparatus used in the Example of this invention.

（式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭素数１〜４の炭化水素基を表し、ｎは１〜１０の整数を表す。）
本発明は、蒸留設備内、例えば、蒸留塔内において、原料中の不純物由来で生じる塩によって発生する圧力損失（本明細書においては、単に「差圧」ということがある。）を、前記一般式〔１〕で表される第４級アンモニウム化合物を塩除去剤として用いることにより解消させることができる。該塩除去剤は、高塩基性を有するため、析出した塩と接触させることにより、塩の塩基部分を置換し、中和塩にすることができる。この中和塩は、吸湿性が高く、流動性に優れるため、結果として、プロセスの流れにより塩を蒸留塔の系外へ排出することが可能となる。また、本発明の差圧解消法には、塩の発生のない状態で、定常的に塩除去剤を蒸留塔内に供給することで、蒸留塔の系内で塩が堆積しにくくし、差圧の発生自体を防止する場合も含まれる。
本発明は、精製する留分への影響がなく、また、生産性の低下や設備への影響もない。 [Differential pressure elimination method]
The method for eliminating the differential pressure of the present invention is a method for eliminating the generation of differential pressure due to the precipitation of salt in a distillation facility, and uses a quaternary ammonium compound represented by the following general formula [1] as a salt removing agent. It is characterized by that.

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10).
The present invention refers to the pressure loss (in the present specification, simply referred to as "differential pressure") caused by salts generated from impurities in raw materials in a distillation facility, for example, in a distillation column. It can be eliminated by using the quaternary ammonium compound represented by the formula [1] as a salt removing agent. Since the salt remover has high basicity, the base portion of the salt can be replaced with a neutralized salt by contacting with the precipitated salt. Since this neutralized salt has high hygroscopicity and excellent fluidity, as a result, the salt can be discharged out of the system of the distillation column by the flow of the process. Further, in the differential pressure relieving method of the present invention, the salt removing agent is constantly supplied into the distillation column in a state where no salt is generated, so that salt is less likely to be deposited in the system of the distillation column, resulting in a difference. It also includes the case of preventing the generation of pressure itself.
The present invention has no effect on the fraction to be purified, nor does it have a decrease in productivity or an effect on equipment.

式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭素数１〜４の炭化水素基を表し、ｎは１〜１０の整数を表す。
前記一般式〔１〕における炭素数１〜４の炭化水素基としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔ−ブチル基等の直鎖状又は分岐状のアルキル基等が挙げられる。
前記第４級アンモニウム化合物の具体例としては、ヒドロキシメチルトリメチルアンモニウムハイドロオキサイド、ヒドロキシメチルトリエチルアンモニウムハイドロオキサイド、ヒドロキシエチルトリメチルアンモニウムハイドロオキサイド、（２−ヒドロキシエチル）トリエチルアンモニウムハイドロオキサイド、（３−ヒドロキシプロピル）トリメチルアンモニウムハイドロオキサイド等が挙げられる。その他、１，８‐ジアザビシクロ［５．４．０］ウンデセン‐７等の超強塩基化合物を用いてもよい。
これらの第４級アンモニウム化合物は１種を単独で用いてもよく、２種以上を併用して用いてもよい。 In the present invention, a quaternary ammonium compound represented by the following general formula [1] is used as the salt remover.

In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10.
The hydrocarbon group having 1 to 4 carbon atoms in the general formula [1] includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group and a t-butyl group. Such as linear or branched alkyl groups such as.
Specific examples of the quaternary ammonium compound include hydroxymethyltrimethylammonium hydroxide, hydroxymethyltriethylammonium hydroxide, hydroxyethyltrimethylammonium hydroxide, (2-hydroxyethyl) triethylammonium hydroxide, and (3-hydroxypropyl). Examples thereof include trimethylammonium hydroxide. In addition, a super strong base compound such as 1,8-diazabicyclo [5.4.0] undecene-7 may be used.
One of these quaternary ammonium compounds may be used alone, or two or more thereof may be used in combination.

R ¹ , R ² and R ³ are each independently preferably a hydrocarbon group having 1 to 3 carbon atoms, and n is preferably an integer of 1 to 4 carbon atoms.
When the quaternary ammonium compound has a low molecular weight, it has excellent solubility in water, and even if the amount added is low, the differential pressure relieving effect can be easily exerted.
The quaternary ammonium compound, R ^1, R ^2, and R ³ is a methyl group, n is a 2 beta-hydroxyethyl trimethylammonium hydroxide (also known as choline) is particularly preferred.

Choline as a salt remover, which is a quaternary ammonium compound, has a high degree of dissociation and a strong basicity. Therefore, as shown in the following chemical reaction formula, choline is produced by reacting with a salt such as ammonium chloride.
^{_{NH 4 Cl + (H 3 C}} ) 3 N + C 2 H 4 OH-OH -
→ NH ₄ OH + (H ₃ C) ₃ N ⁺ C ₂ H ₄ OHCl
Choline chloride is decomposed by heating, but the main products produced by the decomposition are amines typified by trimethylamine and N, N-dimethylaminoethanol, and methyl chloride, and almost no hydrogen chloride is generated.
In addition, choline chloride has high hygroscopicity and excellent fluidity, and as a result, it becomes easy to discharge the salt out of the system of the distillation column by the flow of the process. Furthermore, since the metal corrosiveness is extremely low as compared with other amine hydrochlorides, there is less risk of metal corrosion and path obstruction in the equipment of the distillation facility due to salt deposition.

The quaternary ammonium compound is usually preferably used as an aqueous solution from the viewpoint of handling, and the content in the aqueous solution is not particularly limited, but is preferably 1% by mass or more and less than 100% by mass in the aqueous solution. Is 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 30% by mass or less. When the content of the quaternary ammonium compound is in the above range, the salt can be easily dissolved, and the precipitated salt can be used as a neutralizing salt and discharged out of the system of the distillation column in a short time.

As the salt remover used in the present invention, the quaternary ammonium compound may be used alone, or may be used by containing other components such as ammonia and neutralizing amines in addition to the quaternary ammonium compound. May be good.

The type of salt for which differential pressure is generated in the present invention is not particularly limited, and examples thereof include ammonium chloride, ammonium hydrosulfide, and ammonium sulfate.

FIG. 1 is a flow chart for explaining a method of relieving the differential pressure of the distillation equipment (normal pressure distillation apparatus 1 tower type) according to the embodiment of the present invention. An embodiment of the differential pressure eliminating method of the present invention will be described with reference to the flow chart.

In the distillation facility 1, for example, the raw material oil is heated to a temperature of 350 ° C. or higher in a heating furnace (not shown) through the line 2, and then continuously supplied to the distillation column 3 to distill heavy oil. Fraction, heavy light oil fraction, light oil fraction, heavy naphtha fraction, naphtha fraction, gas fraction, etc.

For example, naphtha discharged from the top of the distillation column 3, which has a low boiling point range of approximately 35 to 80 ° C., passes through line 4, is condensed by an air-cooled cooler 5, and a water-cooled cooler 6, and is condensed in a naphtha receiving tank (overhead). Example of receiver) Collected in 7. In the naphtha receiving tank 7, gas and liquid are separated, fuel gas, liquefied petroleum gas and the like are taken out from the line 8 as a gas distillate, and the naphtha distillate as a liquid distillate is taken out from the line 9. Further, the water (overhead receiver water) collected at the bottom of the naphtha receiving tank 7 is drained from the drainage portion 10 of the naphtha receiving tank 7.
Similarly, for example, a heavy oil fraction having a boiling point of about 350 ° C. or higher is fractionated at the bottom of the column and taken out from the line 13. Further, for example, a heavy gas oil fraction having a boiling point of about 240 to 350 ° C. is taken out from the line 14. Further, for example, the gas oil fraction having a boiling point of about 170 to 250 ° C. is taken out from the line 15 via the side stripper 12, and the heavy naphtha fraction having a boiling point of, for example, about 80 to 180 ° C. is taken out from the side stripper. It is taken out from the line 16 via 12.
In FIG. 1, the heater 11 is used to reflux a part of the fractional distillation fraction distilled from the distillation column into the column from the viewpoint of rectification.

The addition (injection) of the salt remover is not particularly limited, but from the viewpoint of efficiently converting the precipitated salt into a neutralized salt and discharging it to the outside of the distillation column system in a short time, the top of the atmospheric distillation apparatus. Reflux line (process fluid that circulates from the top system to the highest position of the column), top pump around return line (heavy naphtha, fraction corresponding to gasoline fraction; circulating and cooled process fluid), Alternatively, it is preferable to add (inject) to the extraction line of the top pump around (heavy naphtha, fraction corresponding to the gasoline fraction; the process fluid to be circulated and cooled), and the top reflux line is more preferable. Further, the addition (injection) may be performed in a plurality of lines by combining any of the lines.

For example, in FIG. 1, the salt removing agent is preferably added (injected) to any one or a plurality of lines of the salt removing agent injection lines 17a, 17b, or 17c.
Salt remover injection line 17a: Top reflux fluid Salt remover injection line 17b: Top pump around return fluid Salt remover injection line 17c: Top pump around extraction fluid Injection line disperses into process fluid From the viewpoint of sex, it is preferable to use a quill nozzle.

The crude oil atmospheric distillation method is based on an example of a one-tower system, but the present invention is not limited to this, and even if it is a crude oil atmospheric distillation method according to another example of a one-column system, the present invention is not limited to this. Even in the crude oil atmospheric distillation method using a two-tower system or the like, it is possible to eliminate the differential pressure or prevent the generation of the differential pressure by the same method as described above.

The distillation equipment is not particularly limited, but is preferably equipment for a petroleum refining process, a petroleum chemical process, or a coal chemical process.

It is preferable that the process fluid that can come into contact with the distillation column in the distillation facility contains the quaternary ammonium compound represented by the general formula [1].
By containing the quaternary ammonium compound represented by the formula [1] in the process fluid, the generation of salts derived from the process fluid flowing in the distillation equipment, for example, in the distillation column, ancillary tanks, lines, etc. is efficiently generated. It can be suppressed, and the differential pressure in the distillation column can be eliminated or prevented.
The process fluid is not particularly limited, and examples thereof include a naphtha fraction to kerosene, a light oil equivalent fraction, and the like.

（式〔１〕中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭素数１〜４の炭化水素基を表し、ｎは１〜１０の整数を表す。） [Differential pressure relieving agent]
The differential pressure relieving agent of the present invention is a differential pressure relieving agent that eliminates the generation of differential pressure due to the precipitation of salts in a distillation facility, and contains a quaternary ammonium compound represented by the following general formula [1]. It is characterized by that.

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10).

Hydrocarbon groups having 1 to 4 carbon atoms in the general formula [1], specific examples thereof ^{, preferred groups of R 1} , R ² and R ³ , preferred integers of n, and specific examples of the quaternary ammonium compound. Examples, particularly preferable examples, are the same as those described in the general formula [1] relating to the salt remover used in the above-mentioned differential pressure relieving method.
Further, as the differential pressure relieving agent, a quaternary ammonium compound may be used alone, or may be used by containing other components such as ammonia and neutralizing amines in addition to the quaternary ammonium compound. good.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Evaluation of the solubility of the precipitated salt, reprecipitation, and salt discharge into the trap (including analysis of chloride in the components of the discharge) in Examples and Comparative Examples was carried out by the following methods.

(A) Solubility of Precipitated Salt In Examples and Comparative Examples, the wall surface inside the fractional distillation tube and the surface of the irregular glass filling were visually observed during the differential pressure elimination test to see if the precipitated salt was dissolved. , Evaluated according to the following judgment conditions.
〇: Precipitated salt cannot be confirmed, and the transparency of the irregular glass filling increases or becomes transparent.
X: Precipitated salt can be confirmed, and the transparency of the irregular glass filling is reduced or becomes opaque.

(B) During the reprecipitation test, the wall surface inside the fractional distillation tube and the surface of the irregular glass filling were visually observed, and whether or not the dissolved salt was reprecipitated was evaluated under the following determination conditions.
〇: The reprecipitation of the dissolved salt cannot be confirmed, and the transparency of the irregular glass filling increases or becomes transparent.
X: Reprecipitation of the dissolved salt can be confirmed, and the transparency of the irregular glass filling is reduced or becomes opaque.

(C) Discharge of salt to the trap During the test, the salt used is discharged by visually observing the presence or absence of waste in the lower trap in the fractional distillation pipe and analyzing the chloride in the discharge. It was evaluated based on the following judgment conditions.
〇: Emissions can be confirmed, and it can be identified by analysis that the emissions contain chloride.
X: Emissions cannot be confirmed, or emissions can be confirmed, but it cannot be identified by analysis that the emissions contain chloride.
Chloride analysis was performed by the following method.
<Chloride analysis method>
A capillary electrophoresis analyzer (Agilent 7100, manufactured by Agilent Technologies) was used to analyze and evaluate the amount of chlorine ions in the components of the emissions.

<Hygroscopicity test>
(Experimental Example 1)
The hygroscopicity of ammonium chloride and choline chloride was examined by the following hygroscopicity test.

In the hygroscopicity test, 5 g of ammonium chloride evaporated to dryness at 105 ° C. for 2 hours or more and choline chloride evaporated to dryness at 105 ° C. for 2 hours or more were placed in a charley, and the mass of each including the charley was measured. bottom. Then, it is placed in a desiccator conditioned under the following conditions, and contains ammonium chloride or choline chloride every 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours and 24 hours. , The amount of water absorption was calculated by measuring the mass of each charley.
Humidity control conditions: 25 ° C. Relative humidity 35%; Zinc nitrate hexahydrate saturated aqueous solution is placed in a desiccator 1
Leave for 2 hours
25 ° C. Relative humidity 60%; Saturated aqueous solution of magnesium acetate tetrahydrate in a desiccator
The hygroscopicity of ammonium chloride and choline chloride was evaluated by evaluating the change (% / hour) in the mass increase rate before and after the test at each elapsed time. The results are shown in Table 1.

From Table 1, it can be seen that choline chloride has a much higher hygroscopic capacity than ammonium chloride.

<Differential pressure elimination test at laboratory level>
In petroleum process equipment, etc., the conditions of distillation equipment where salt precipitation occurs are simulated, and evaluation of the solubility of precipitated salt, reprecipitation, and salt discharge into traps (including analysis of chloride in the components of the discharge). In order to carry out the above, a desktop test apparatus shown in FIG. 2 was prototyped.
This device reproduces the temperature conditions (top pump around to 90 to 140 ° C equivalent at the top of the tower) where salt precipitation generally occurs in the distillation column of an oil refining facility.
FIG. 2 is a block diagram of the desktop test apparatus.
In the desktop test apparatus 21, the temperature is controlled by the heater (B) 26 at the bottom, the salt introduction pipe 32 containing the salt 31, the lower trap 33 for receiving the discharged chloride, and the heater for controlling the temperature inside the fractional distillation pipe 22. In the fractional distillation pipe 22 provided with the C) 27, the heater (D) 28, and the irregular glass filling 30, the salt 31 in the salt introduction pipe 32 is determined by the heater (A) 25 via the flow meter 24. It is dissolved and evaporated by nitrogen 23 as a carrier gas heated at the above temperature, and is introduced from the lower part of the fractional distillation tube 22. On the other hand, the salt removing agent 29a or the washing water 29b in the tank 29 is introduced from the top of the fractional distillation pipe 22 via the pump 34. The temperature of each heater unit is monitored by using each thermometer 35 to 38.

(Example 1)
The test conditions, the salt used, and the differential pressure relieving agent are shown below.
Desktop test equipment and filling material: Heat-resistant glass Carrier gas: Nitrogen fractionation tube: Diameter inner dimension 15 cm, height inner dimension 40 cm
Carrier gas temperature (heater (A)): set temperature 200 ° C
Salt heating temperature (heater (B)): set temperature 180 ° C
Heater (C): Set temperature 120 ° C
Heater (D): Set temperature 90 ° C
Salt used: Ammonium chloride (manufactured by Kishida Chemical Co., Ltd., special grade: 99.5%) 5 g
Differential pressure relieving agent: Choline aqueous solution (40% by mass or more) 3 g / min

Evaluation of solubility of precipitated salt, reprecipitation, and salt discharge to the trap (analysis of chloride in the components of the discharge) by going through the following processes (a) to (d) using the desktop test apparatus. Including). The results are shown in Table 2.
(A) The salt is heated and supplied to the fractional distillation tube by a stream of heated nitrogen gas.
(B) Except for the top and end (lower trap) of the fractional distillation tube, heat it.
Warming avoids salt precipitation in the region between the top and the ends.
(C) Salt is deposited on the filling in the open portion of the fractional distillation tube.
(D) A salt remover is added from the top of the fractional distillation tube.

(Comparative Example 1)
In the process (d) of Example 1, the solubility, reprecipitation, and precipitation of the precipitated salt were the same as in Example 1 except that pure water was added (2 mL / min) instead of dropping choline as a salt remover. Evaluation of salt discharge into the trap (including analysis of chloride in the components of the discharge) was performed. The results are shown in Table 2.

From Table 2, it can be confirmed that the choline used as the differential pressure relieving agent does not cause salt reprecipitation, and chloride that causes the differential pressure in the distillation column is discharged to the trap.

According to the differential pressure relieving method of the present invention, the pressure loss (differential pressure) generated by the salt generated from impurities in the raw material in the distillation facility can be eliminated during operation, and the equipment utilization efficiency can be improved. The life of equipment can be extended. Furthermore, since there is no effect on the fraction to be refined, it is expected that the manufacturing cost will be reduced, including the improvement of the yield. Furthermore, since the present invention has no adverse effect on production or equipment, it can be applied steadily.

1: Distillation equipment 2, 4, 8, 9: Line 3: Distillation tower 5: Air-cooled cooler 6: Water-cooled cooler 7: Naphtha receiving tank 10: Drainage part 11: Heater 12: Side stripper 13, 14, 15 , 16: Lines 17a, 17b, 17c: Salt remover injection line 21: Desktop test equipment 22: Fractional distillation tube 23: Nitrogen
24: Flow meter 25: Heater (A)
26: Heater (B)
27: Heater (C)
28: Heater (D)
29: Tank 29a: Salt remover 29b: Washing water 30: Glass irregular filling 31: Salt 32: Salt introduction pipe 33: Lower trap 34: Vacuum pump 35, 36, 37, 38: Thermometer

Claims (6)

A method for eliminating the generation of differential pressure due to the reprecipitation of a salt in a distillation facility, wherein the salt is a salt generated from impurities in crude oil in the distillation facility, and is represented by the following general formula [1]. A method for relieving differential pressure using a quaternary ammonium compound as a salt remover.

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10). The first aspect of the above general formula [1], wherein R ¹ , R ² and R ³ are independently hydrocarbon groups having 1 to 3 carbon atoms, and n is an integer of 1 to 4 carbon atoms. Differential pressure elimination method. The method for relieving differential pressure according to claim 1 or 2, wherein the quaternary ammonium compound is β-hydroxyethyltrimethylammonium hydroxide. The method for relieving differential pressure according to any one of claims 1 to 3, wherein the distillation facility is a facility for a petroleum refining process or a petrochemical process. The differential pressure elimination according to any one of claims 1 to 4, wherein the process fluid that can come into contact with the distillation column in the distillation facility contains a quaternary ammonium compound represented by the general formula [1]. Method. A differential pressure relieving agent that eliminates the generation of differential pressure due to the reprecipitation of salt in a distillation facility, and the salt is a salt generated from impurities in crude oil in the distillation facility, and is represented by the following general formula [1]. A differential pressure relieving agent containing a quaternary ammonium compound.

(In the formula [1], R ¹ , R ² and R ³ each independently represent a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10).

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