JP7421288B2 - Quench tower and gas cooling method - Google Patents

Description

The present invention relates to a quench tower and a gas cooling method suitable for cooling a gas to be cooled that contains impurities that precipitate solid components when cooled.

Conventionally, the method for producing 1,3-butadiene (hereinafter also simply referred to as "butadiene") is to use a fraction having 4 carbon atoms (hereinafter also referred to as "C4 fraction") obtained by cracking naphtha. A method has been adopted in which components other than butadiene are separated from the oil by distillation.
Demand for butadiene is increasing as a raw material for synthetic rubber, etc., but the supply of C4 fraction is decreasing due to factors such as the shift in the ethylene manufacturing method from cracking naphtha to thermal decomposition of ethane. Therefore, there is a need for the production of butadiene that does not use C4 fraction as a raw material.

Therefore, as a method for producing butadiene, a method of separating butadiene from a generated gas obtained by oxidative dehydrogenation of n-butene is attracting attention (see, for example, Patent Documents 1 to 4). This production method includes an oxidative dehydrogenation reaction step in which a raw material gas containing n-butene and a molecular oxygen-containing gas (specifically, for example, air) is subjected to an oxidative dehydrogenation reaction; The method includes a cooling step for cooling the product gas obtained in the step, and a product gas separation step for separating butadiene from the product gas cooled by this step.

JP2012-72086A Japanese Patent Application Publication No. 2014-198707

However, in the above method for producing butadiene, reaction by-products such as carbonyl compounds such as acetaldehyde and methyl vinyl ketone, and organic acids such as carboxylic acids are generated. Such reaction by-products are precipitated, for example, when the generated gas is rapidly cooled in the cooling process, and solid components adhere to the solid packing in the quench tower used. When the amount of solid components attached increases over time, a pressure difference occurs within the quench tower, making it impossible to continue the cooling process. For this reason, it is necessary to disassemble the quench tower to remove the attached solid components, and it is therefore difficult to cool the produced gas stably over a long period of time.

The present invention has been made based on the above-mentioned circumstances, and its purpose is to prevent or suppress a large amount of solid components precipitated by cooling from adhering to the solid packing, and to prevent or reduce the amount of gas to be cooled. The object of the present invention is to provide a quench tower that can stably perform cooling over a long period of time.
Another object of the present invention is to provide a gas cooling method that can stably cool a gas to be cooled over a long period of time.

The quench tower of the present invention is equipped with a gas-liquid contacting member inside, and the quench tower in which the gas to be cooled supplied from the lower part of the tower is cooled by the cooling water supplied from the upper part of the tower,
The cooled gas precipitates solid components that adhere to the gas-liquid contacting member by being cooled,
a cleaning mechanism that supplies cleaning water to the gas-liquid contact member;
The cleaning mechanism includes a jetting head that sprays cleaning water to the gas-liquid contacting member at the lowest stage,
A supply amount of the cleaning water in the cleaning mechanism is 861 to 1076 L/min.

In the quench tower of the present invention, a plurality of the gas-liquid contacting members are disposed in the tower so as to overlap each other vertically with a space therebetween, and the cleaning mechanism is attached to the lowest gas-liquid contacting member. It is preferable that the washing water is supplied from above.

Moreover, in the quench tower of the present invention, it is preferable that the cleaning mechanism has a jetting head that jets cleaning water to the gas-liquid contacting member.

Moreover, in the quench tower of the present invention, it is preferable that the cleaning mechanism is driven when specified.

The gas cooling method of the present invention is a gas cooling method in which a gas to be cooled supplied from the lower part of the tower is cooled by cooling water supplied from the upper part of the tower in a quench tower equipped with a gas-liquid contact member, the method comprising:
The cooled gas precipitates solid components that adhere to the gas-liquid contact member by being cooled,
Supplying cleaning water by jet to the gas-liquid contacting member at the lowest stage,
The cleaning water is supplied to the gas-liquid contacting member at a supply rate of 861 to 1076 L/min.

In the gas cooling method of the present invention, it is preferable to supply cleaning water by spraying it onto the gas-liquid contacting member.

According to the quench tower of the present invention, since it has a cleaning mechanism that supplies cleaning water to the gas-liquid contact member, it is possible to prevent or suppress a large amount of solid components precipitated by cooling from adhering to the gas-liquid contact member. Therefore, the gas to be cooled can be stably cooled over a long period of time.
According to the gas cooling method of the present invention, since cleaning water is supplied to the gas-liquid contact member, it is prevented or suppressed that a large amount of solid components precipitated by cooling adheres to the gas-liquid contact member, and as a result, The gas to be cooled can be stably cooled over a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory cross-sectional view schematically showing the configuration of an example of a quench tower of the present invention. FIG. 2 is a flow diagram showing an example of a specific method for producing butadiene using the quench tower of the present invention.

Embodiments of the present invention will be described below.

[Quenching tower and gas cooling method]
FIG. 1 is an explanatory cross-sectional view schematically showing the configuration of an example of the quench tower of the present invention.
The quench tower 2 is configured to rapidly cool the gas to be cooled by bringing cooling water into countercurrent contact with the gas to be cooled, and has a cylindrical tower body 20 that extends in the vertical direction and is closed at both ends. has.

A gas inlet 25 for introducing the gas to be cooled into the interior of the tower body 20 is provided at a lower position in the peripheral wall portion 21 of the tower body 20 . Furthermore, a gas outlet 26 is provided in the tower top 22 of the tower main body 20 to lead out the gas to be cooled from inside the tower main body 20 . Further, a cooling water outlet 27 is provided in the tower bottom portion 23 of the tower body 20 to lead out cooling water supplied from a cooling water supply mechanism 35, which will be described later.

A gas-liquid contacting member 30 is provided in the tower body 20 at a position between the gas inlet 25 and the gas outlet 26 . In the illustrated example, a plurality of gas-liquid contact members 30 are arranged so as to be vertically overlapped with each other with a space therebetween. A cooling water supply mechanism 35 that supplies cooling water to cool the gas to be cooled is provided above the gas-liquid contacting member 30 at the uppermost stage. A cleaning mechanism 40 that cleans the gas-liquid contact member 30 by supplying cleaning water to the gas-liquid contact member 30 at the lowest stage is located above the gas-liquid contact member 30 at the lowest stage. It is provided.

As the gas-liquid contacting member 30, when the quench tower 2 is configured as a packed tower, irregular packing can be used. Specific examples of irregular packing include Raschig rings, Paul rings, and cascade mini rings. In addition, when the quench tower 2 is constituted by a tray column, a shelf plate is used as the gas-liquid contacting member 30.

The cooling water supply mechanism 35 has a spray head 36 that sprays cooling water. This spray head 36 is arranged above the uppermost gas-liquid contacting member 30 in the tower body 20 so as to face downward. As the cooling water supplied from the cooling water supply mechanism 35, water or alkaline water can be used. The temperature of the cooling water is appropriately determined depending on the cooling temperature of the gas to be cooled, but is preferably 10°C or more and 90°C or less, more preferably 20°C or more and 70°C or less, and particularly preferably 20°C. The temperature is above 40°C. Further, the amount of cooling water supplied from the spray head 36 is, for example, 1200 to 1500 L/min.

The cleaning mechanism 40 includes a jetting head 41 that supplies cleaning water to the lowermost gas-liquid contacting member 30 by jetting it. This injection head 41 is arranged above the lowest gas-liquid contacting member 30 in the tower main body 20 so as to face downward.
As the ejection head 41, it is preferable to use one in which the ejected cleaning water forms a conical spray pattern. Further, the conical spray pattern ejected from the ejection head 41 is determined by the ratio (L/D) of the spray distance (height of the formed cone) L and the spray width (diameter of the bottom surface of the formed cone) D. is preferably 2 or less, more preferably 0.6 to 1.6.

As the cleaning water supplied from the cleaning mechanism 40, water or alkaline water can be used. The temperature of the washing water is not particularly limited, but is, for example, 5 to 30°C.
Further, the amount of cleaning water supplied from the jetting head 41 is, for example, 861 to 1076 L/min.
The amount of cleaning water supplied per unit area of the surface of the gas-liquid contacting member 30 is, for example, 44 to 55 L/m ² .
Further, the amount of cleaning water used for one cleaning process for the gas-liquid contact member 30 is, for example, 144 to 179 L.

This cleaning mechanism 40 can be controlled to be driven at a designated time during the cooling process of the water to be cooled. For example, during the cooling process of the water to be cooled, the operation of driving and stopping the cleaning mechanism 40 is repeatedly performed every predetermined period of time, for example, 6 to 8 hours, that is, the driving of the cleaning mechanism 40 is intermittently performed. It is possible to control the cleaning mechanism 40 so that the cleaning is carried out in a consistent manner.

In the above-described quench tower 2, the gas to be cooled is introduced into the tower body 20 through the gas inlet 25, and is led out through the gas outlet 26. Thereby, the gas to be cooled is circulated inside the tower main body 20 from the lower part of the tower main body 20 to the upper part via the gas-liquid contact member 30. On the other hand, the cooling water supplied by the cooling water supply mechanism 35 is sprayed downward from the spray head 36. As a result, the cooling water comes into countercurrent contact with the gas to be cooled flowing upward inside the tower body 20, so that the gas to be cooled is rapidly cooled. The supplied cooling water is led out from the cooling water outlet 27 to the outside of the tower body 20 .

In the above, when the gas to be cooled precipitates solid components that adhere to the gas-liquid contact member 30 by cooling, the precipitated solid components adhere to the gas-liquid contact member 30 at the lowest stage. When the cleaning mechanism 40 is driven during the cooling process of the gas to be cooled, cleaning water is injected and supplied from the jetting head 41 to the gas-liquid contact member 30 at the lowest stage. Solid components adhering to the gas-liquid contact member 30 are removed.

As described above, since the quench tower 2 of the present invention includes the cleaning mechanism 40 that supplies cleaning water to the gas-liquid contact member 30, a large amount of solid components precipitated by cooling adheres to the gas-liquid contact member 30. Therefore, cooling of the gas to be cooled can be stably performed over a long period of time.

[Method for producing 1,3-butadiene]
INDUSTRIAL APPLICABILITY The present invention can be suitably used in the step of cooling the produced gas in a method for producing 1,3-butadiene by subjecting a raw material gas containing n-butene to an oxidative dehydrogenation reaction with oxygen.
That is, according to the present invention, a generated gas containing 1,3-butadiene obtained by an oxidative dehydrogenation reaction between a raw material gas containing n-butene and oxygen is passed from the lower part of a quench tower equipped with a gas-liquid contact member. In a method for producing butadiene, the method includes a cooling step of cooling the generated gas by supplying cooling water from the upper part of the quench tower,
It is possible to provide a method for producing butadiene, characterized in that a cleaning treatment step of supplying cleaning water to the gas-liquid contacting member in the quench tower is performed.

This method for producing butadiene (1,3-butadiene) has the steps shown in (1) to (3) below, and by going through the steps (1) to (3) below, n -Produces butadiene from raw material gas containing butene.

(1) A first step in which a product gas containing 1,3-butadiene is obtained by an oxidative dehydrogenation reaction between a raw material gas containing 1-butene and 2-butene and a molecular oxygen-containing gas. (2) The product gas obtained in the first step is Second step of cooling the generated gas (3) The generated gas that has passed through the second step is mixed with other gases including molecular oxygen, inert gases, and 1,3-butadiene by selective absorption into an absorption solvent. The third step of separating into

FIG. 2 is a flow diagram showing an example of a specific method for producing butadiene using the quench tower of the present invention. Hereinafter, a specific example of the above method for producing butadiene will be described in detail using FIG. 2.
The method for producing butadiene in the example shown in FIG. and a circulation step in which molecular oxygen and inert gases obtained in the third step are refluxed to the first step, that is, fed as reflux gas. be.
Furthermore, in the method for producing butadiene shown in the example shown in FIG. 2, the absorption solvent used in the third step is recycled.

<First step>
In the first step, a product gas containing butadiene (1,3-butadiene) is obtained by subjecting a raw material gas and a molecular oxygen-containing gas to an oxidative dehydrogenation reaction in the presence of a metal oxide catalyst. In this first step, the oxidative dehydrogenation reaction between the raw material gas and the molecular oxygen-containing gas is performed in the reactor 1, as shown in FIG. Here, the reactor 1 is a tower-like type having a gas inlet at the top, a gas outlet at the bottom, and a catalyst layer (not shown) formed by filling the inside with a metal oxide catalyst. be. In this reactor 1, a gas inlet is connected to a pipe 100 and a pipe 112 via a pipe 116, and a gas outlet is connected to a pipe 101.

To explain the first step in detail, a raw material gas and a molecular oxygen-containing gas are supplied to the reactor 1 via a pipe 100 that communicates with a pipe 116, and if necessary, an inert gas and water (steam ) (hereinafter collectively referred to as "new supply gas"). Before the newly supplied gas is introduced into the reactor 1, it is heated to about 200° C. or more and 400° C. or less by a preheater (not shown) disposed between the reactor 1 and the pipe 100. In addition, reflux gas from the circulation process is supplied to the reactor 1 through a pipe 112 that communicates with a pipe 116, together with a new supply gas supplied through a pipe 100, after being heated by the preheater. be done. That is, a mixed gas of freshly supplied gas and reflux gas is supplied to the reactor 1 after being heated by a preheater. Here, the new supply gas and the reflux gas may be directly supplied to the reactor 1 from separate pipes, but as shown in FIG. 2, they may be supplied in a mixed state from a common pipe 116. It is preferable that By providing the common piping 116, a mixed gas containing various components can be supplied to the reactor 1 in a uniformly mixed state in advance, so that uneven mixed gas can be partially prevented in the reactor 1. This can prevent the formation of explosive atmosphere.
In the reactor 1 to which the mixed gas is supplied, butadiene (1,3-butadiene) is produced by an oxidative dehydrogenation reaction between the raw material gas and the molecular oxygen-containing gas, and a produced gas containing the butadiene is obtained. It will be done. The obtained generated gas flows out from the gas outlet of the reactor 1 into the pipe 101.

(raw material gas)
As the raw material gas, a gaseous substance obtained by gasifying n-butene, which is a monoolefin having 4 carbon atoms, using a vaporizer (not shown) is used. This source gas is a combustible gas. In the present invention, "n-butene" means a linear butene, and specifically includes 1-butene, cis-2-butene, and trans-2-butene.
Further, the source gas may contain arbitrary impurities. Specific examples of this impurity include branched monoolefins such as i-butene, and saturated hydrocarbons such as propane, n-butane, and i-butane. Further, the raw material gas may contain 1,3-butadiene, which is the production target, as an impurity. The amount of impurities in the raw material gas is usually 60% by volume or less, preferably 40% by volume or less, more preferably 25% by volume or less, particularly preferably 5% by volume or less, based on 100% by volume of the raw material gas. When the amount of impurities is excessive, the concentration of linear butene in the raw material gas tends to decrease, resulting in a slow reaction rate and an increase in the amount of by-products.

As the raw material gas, for example, a fraction containing linear butene as a main component (raffinate 2 ) or a butene fraction produced by a dehydrogenation reaction or an oxidative dehydrogenation reaction of n-butane can be used. It is also possible to use gases containing highly purified 1-butene, cis-2-butene, trans-2-butene, and mixtures thereof obtained by dimerization of ethylene. Furthermore, fluid catalytic cracking (Fluid Catalytic Cracking) is a process in which the heavy oil fraction obtained when crude oil is distilled at an oil refinery plant is cracked using a powdered solid catalyst in a fluidized bed to convert it into low-boiling point hydrocarbons. Gas containing a large amount of hydrocarbons with a carbon number of 4 (hereinafter sometimes abbreviated as "FCC-C4") obtained from cracking) can be directly used as the raw material gas, and phosphorus etc. It is also possible to use the raw material gas from which impurities have been removed.

(Molecular oxygen-containing gas)
The molecular oxygen-containing gas is usually a gas containing 10% by volume or more of molecular oxygen (O ₂ ). In this molecular oxygen-containing gas, the concentration of molecular oxygen is preferably 15% by volume or more, more preferably 20% by volume or more.
In addition to molecular oxygen, molecular oxygen-containing gases include molecular nitrogen (N ₂ ), argon (Ar), neon (Ne), helium (He), carbon monoxide (CO), and carbon dioxide (CO ₂ ). It may also contain any gas such as water (steam). When the arbitrary gas is molecular nitrogen, the amount of any gas in the molecular oxygen-containing gas is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. When the arbitrary gas is a gas other than molecular nitrogen, the amount is usually 10% by volume or less, preferably 1% by volume or less. If the amount of any given gas is excessive, there is a possibility that the required amount of molecular oxygen cannot coexist with the raw material gas in the reaction system (inside the reactor 1).
In the first step, a preferable specific example of the molecular oxygen-containing gas is air.

(Inert gas)
The inert gases are preferably supplied to the reactor 1 together with the raw material gas and the molecular oxygen-containing gas.
By supplying inert gases to the reactor 1, the concentrations (relative concentrations) of the raw material gas and molecular oxygen are adjusted so that the mixed gas does not form explosive gas in the reactor 1. can do.
Examples of inert gases include molecular nitrogen (N ₂ ), argon (Ar), and carbon dioxide (CO ₂ ). These can be used alone or in combination of two or more. Among these, molecular nitrogen is preferred from an economical point of view.

(Water (steam))
Preferably, water is supplied to the reactor 1 together with the raw material gas and the molecular oxygen-containing gas.
By supplying water to the reactor 1, similar to the above-mentioned inert gases, the raw material gas and molecular oxygen are prevented from forming explosive gas in the reactor 1. Concentration (relative concentration) can be adjusted.

(mixed gas)
Since the mixed gas contains a flammable source gas and molecular oxygen, its composition is adjusted so that the concentration of the source gas does not fall within the explosive range.
Specifically, each gas constituting the mixed gas (specifically, raw material gas, molecular oxygen-containing gas (air), and inert gases and water (steam) used as necessary) is The gas in the reactor 1 is monitored while the flow rate is monitored by a flow meter (not shown) installed in the pipes (specifically, the pipes communicating with the pipe 100 (not shown) and the pipe 112) that supply the reactor 1. Control the composition of the gas mixture at the inlet. For example, the composition of the new supply gas supplied to the reactor 1 via the pipe 100 is controlled depending on the molecular oxygen concentration of the reflux gas supplied to the reactor 1 via the pipe 112.
In this specification, the term "explosive range" refers to a range in which the mixed gas has a composition that will ignite in the presence of some ignition source. It is known that if the concentration of combustible gas is lower than a certain value, it will not ignite even if an ignition source is present, and this concentration is called the lower explosive limit. The lower explosive limit is the lower limit of the explosive range. It is also known that if the concentration of flammable gas is higher than a certain value, it will not ignite even if an ignition source is present, and this concentration is called the upper explosive limit. The upper explosive limit is the upper limit of the explosive range. These values depend on the concentration of molecular oxygen, and in general, the lower the concentration of molecular oxygen, the closer the two values become, and when the concentration of molecular oxygen reaches a certain value, the two values match. . The concentration of molecular oxygen at this time is called the critical oxygen concentration. Therefore, in a mixed gas, if the concentration of molecular oxygen is lower than the critical oxygen concentration, the mixed gas will not ignite regardless of the concentration of the raw material gas.

Specifically, in the mixed gas, the total concentration of 1-butene and 2-butene is 2% by volume or more at 30% by volume in 100% by volume of the mixed gas from the viewpoint of productivity of butadiene and suppression of burden on the metal oxide catalyst. It is preferably at most 3% by volume and at most 25% by volume, particularly preferably at least 5% by volume and at most 20% by volume. If the total concentration of 1-butene and 2-butene is too low, the productivity of butadiene may decrease. On the other hand, if the total concentration of 1-butene and 2-butene is excessive, the burden on the metal oxide catalyst may increase.

Further, in the mixed gas, the concentration (relative concentration) of molecular oxygen with respect to the raw material gas is preferably 50 parts by volume or more and 170 parts by volume or less, more preferably 70 parts by volume or more, with respect to 100 parts by volume of the raw material gas. It is 160 parts by volume or less. If the concentration of molecular oxygen in the mixed gas deviates from the above range, it tends to be difficult to adjust the concentration of molecular oxygen at the gas outlet of reactor 1 by adjusting the reaction temperature. If the concentration of molecular oxygen at the gas outlet of the reactor 1 cannot be controlled by the reaction temperature, it becomes impossible to suppress the decomposition of the target product and the occurrence of side reactions inside the reactor 1. There is a risk.

Further, in the mixed gas, the concentration (relative concentration) of molecular nitrogen with respect to the raw material gas is preferably 400 parts by volume or more and 1800 parts by volume or less, more preferably 500 parts by volume or more, with respect to 100 parts by volume of the raw material gas. It is 1700 parts by volume or less. Further, the concentration (relative concentration) of water (steam) with respect to the raw material gas is preferably 0 parts by volume or more and 900 parts by volume or less, more preferably 80 parts by volume or more and 300 parts by volume with respect to 100 parts by volume of the raw material gas. It is as follows. In either case, if the concentration of molecular nitrogen or the concentration of water is excessive, the production efficiency of butadiene tends to decrease as the value increases because the concentration of the raw material gas decreases. On the other hand, if the concentration of molecular nitrogen or the concentration of water is too low, in either case, the smaller the value, the more the concentration of the raw material gas will reach the explosive range, or the heat removal of the reaction system will be described later. tends to be difficult.

(Metal oxide catalyst)
As the metal oxide catalyst, a composite oxide catalyst containing molybdenum and bismuth is used. As such a composite oxide catalyst, for example, one containing at least molybdenum (Mo), bismuth (Bi) and iron (Fe) can be used, and a specific example thereof is the composition formula (1) below. Examples include those containing a composite metal oxide represented by:

Composition formula (1):
Mo _a Bi _b Fe _c X _d Y _e Z _f O _g

In the above compositional formula (1), X is at least one member selected from the group consisting of Ni and Co. Y is at least one member selected from the group consisting of Li, Na, K, Rb, Cs and Tl. Z is at least one selected from the group consisting of Mg, Ca, Ce, Zn, Cr, Sb, As, B, P and W. a, b, c, d, e, f and g each independently indicate the atomic ratio of each element; when a is 12, b is 0.1 to 8, and c is 0.1 to 20, d is 0 to 20, e is 0 to 4, f is 0 to 2, and g is the number of atoms of the oxygen element necessary to satisfy the valence of each component above. .

The composite oxide catalyst containing the composite metal oxide represented by the above compositional formula (1) has high activity and high selectivity in the method of producing butadiene using oxidative dehydrogenation reaction, and has a long life. Excellent stability.

The method for preparing the composite oxide catalyst is not particularly limited, and may include an evaporation drying method, a spray drying method, and an oxidation method using raw materials of each element related to the composite metal oxide constituting the composite oxide catalyst to be prepared. A known method such as a mixture method can be used.
The raw materials for each of the above elements are not particularly limited, and include, for example, oxides, nitrates, carbonates, ammonium salts, hydroxides, carboxylates, ammonium carboxylate salts, ammonium halides, and hydrogen acids of the component elements. , alkoxides, etc.

Further, the composite oxide catalyst may be used by being supported on an inert carrier. Examples of carrier species include silica, alumina, and silicon carbide.

(oxygen dehydrogenation reaction)
In the first step, when starting the oxidative dehydrogenation reaction, first start supplying molecular oxygen-containing gas, inert gases, and water (steam) to the reactor 1, and adjust their supply amounts. The concentration of molecular oxygen at the gas inlet of reactor 1 is adjusted to be below the limit oxygen concentration by It is preferable to increase the supply amount of the raw material gas and the supply amount of the molecular oxygen-containing gas so that the upper explosive limit is exceeded.
Further, when increasing the supply amount of the raw material gas and the molecular oxygen-containing gas, the supply amount of the mixed gas may be kept constant by decreasing the supply amount of water (steam). By doing so, the gas residence time in the piping and the reactor 1 can be kept constant, and fluctuations in the pressure in the reactor 1 can be suppressed.

The pressure in the reactor 1 (specifically, the pressure at the gas inlet of the reactor 1), that is, the pressure in the first step, is preferably 0.1 MPaG or more and 0.4 MPaG or less, more preferably 0.15 MPaG. It is not less than 0.35 MPaG, and more preferably not less than 0.2 MPaG and not more than 0.3 MPaG.
By setting the pressure in the first step within the above range, the reaction efficiency in the oxidative dehydrogenation reaction is improved. If the pressure in the first step is too low, the reaction efficiency in the oxidative dehydrogenation reaction tends to decrease. On the other hand, if the pressure in the first step is excessive, the yield in the oxidative dehydrogenation reaction tends to decrease.

In addition, in the oxidative dehydrogenation reaction, the gas hourly space velocity (GHSV) determined by the following formula (1) is preferably 500 h ^-1 or more and 5000 h ^-1 or less, more preferably 800 h ^-1 or more and 3000 h ^-1 or less, more preferably 1000 h ^-1 or more and 2500 h ^-1 or less.
By setting the GHSV within the above range, the reaction efficiency in the oxidative dehydrogenation reaction can be further improved.

Formula (1):
GHSV [h ^-1 ] = Atmospheric pressure equivalent gas flow rate [Nm ³ /h] ÷ Catalyst layer volume [m ³ ]

In the above formula (1), the "catalyst layer volume" indicates the volume (apparent volume) of the entire catalyst layer including voids.

In addition, in the oxidative dehydrogenation reaction, the real volume gas hourly space velocity (actual volume GHSV) determined by the following formula (2) is preferably 500 h ^-1 or more and 2300 h ^-1 or less, more preferably 600 h ^-1 It is not less than 2000 h ^-1 , and more preferably not less than 700 h ^-1 and not more than 1500 h ^-1 .
By setting the actual volume GHSV within the above range, the reaction efficiency in the oxidative dehydrogenation reaction can be further improved.

Formula (2):
Actual volume GHSV [h ^-1 ] = Actual gas flow rate [m ³ /h] ÷ Catalyst layer volume [m ³ ]

In the above formula (2), the "catalyst layer volume" indicates the volume (apparent volume) of the entire catalyst layer including voids, as in the above formula (1).

Further, in the oxidative dehydrogenation reaction, since the oxidative dehydrogenation reaction is an exothermic reaction, the temperature of the reaction system increases and multiple types of byproducts may be generated. As by-products, unsaturated carbonyl compounds having 3 to 4 carbon atoms such as acrolein, acrylic acid, methacrolein, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, methyl vinyl ketone, crotonaldehyde, and crotonic acid are produced. As the concentration in the generated gas increases, various adverse effects occur. Specifically, since the unsaturated carbonyl compound is dissolved in the absorption solvent etc. that is recycled in the third step, impurities accumulate in the absorption solvent etc., which tends to induce the precipitation of deposits on each member. .

In the oxidative dehydrogenation reaction, a method for controlling the concentration of the unsaturated carbonyl compound within a certain range includes a method of adjusting the reaction temperature of the oxidative dehydrogenation reaction. Further, by adjusting the reaction temperature, the concentration of molecular oxygen at the gas outlet of the reactor 1 can be kept within a certain range.
Specifically, the reaction temperature is preferably 300°C or higher and 400°C or lower, more preferably 320°C or higher and lower than 380°C.
By setting the reaction temperature within the above range, coking (precipitation of solid carbon) in the metal oxide catalyst can be suppressed, and the concentration of the unsaturated carbonyl compound in the generated gas can be kept within a certain range. It becomes possible. Furthermore, it is also possible to maintain the concentration of molecular oxygen at the gas outlet of the reactor 1 within a certain range.
On the other hand, if the reaction temperature is too low, the conversion rate of n-butene may decrease. Furthermore, if the reaction temperature is too high, the concentration of the unsaturated carbonyl compound increases, which tends to accumulate impurities in the absorption solvent and cause coking in the metal oxide catalyst.

Here, as a preferred specific example of the method of adjusting the reaction temperature, for example, the reactor 1 is appropriately cooled by removing heat using a heat medium (specifically, dibenzyltoluene, nitrite, etc.). One example is a method of controlling the temperature of the catalyst layer to be constant.

(Produced gas)
The generated gas includes 1,3-butadiene, which is the target product of the oxidative dehydrogenation reaction between the raw material gas and the molecular oxygen-containing gas, as well as reaction byproducts, unreacted raw material gas, unreacted molecular oxygen, Contains concentration adjustment gas, etc. Reaction by-products include carbonyl compounds and heterocyclic compounds. Here, carbonyl compounds include ketones, aldehydes, and organic acids.
Ketones include methyl vinyl ketone, acetophenone, benzophenone, anthraquinone and fluorenone.
Examples of aldehydes include acetaldehyde, acrolein, methacrolein, crotonaldehyde, and benzaldehyde.
Examples of organic acids include maleic acid, fumaric acid, acrylic acid, phthalic acid, benzoic acid, crotonic acid, tetrahydrophthalic acid, isophthalic acid, terephthalic acid, methacrylic acid, and phenol.
Furthermore, examples of the heterocyclic compound include furan and the like.

<Second process>
In the second step, the generated gas obtained in the first step is cooled. In this second step, the produced gas from the first step is cooled by the quench tower 2 and the cooling heat exchanger 3 of the present invention.
Specifically, the produced gas from the first step, that is, the produced gas discharged from the reactor 1, is fed to the quench tower 2 via the pipe 101, cooled in the quench tower 2, and then passed through the pipe. 104 to the cooling heat exchanger 3, and is further cooled in the cooling heat exchanger 3. The generated gas from the first step cooled by the quench tower 2 and the cooling heat exchanger 3 in this manner flows out from the cooling heat exchanger 3 into the pipe 105.
By passing through this second step, the gas produced from the first step is purified. Specifically, a portion of byproducts contained in the generated gas from the first step are removed.

(quench tower)
In the quench tower 2, the generated gas from the first step is rapidly cooled to a temperature of, for example, about 30° C. or higher and 90° C. or lower by bringing a cooling medium into countercurrent contact with the generated gas.
A pipe 101 whose one end is connected to a gas outlet of the reactor 1 is connected to a gas inlet of the quench tower 2, and a pipe 104 is connected to a gas outlet of the quench tower 2. Further, a pipe 102 is connected to an injection head (not shown) of a cooling water supply mechanism (not shown) in the quench tower 2, and a pipe 103 is connected to a cooling water outlet of the quench tower 2.

Further, in the quench tower 2 in operation, the internal temperature is preferably 10°C or more and 100°C or less, more preferably 20°C or more and 90°C or less.

In addition, the pressure of the quench tower 2 during operation (specifically, the pressure of the gas outlet of the quench tower 2), that is, the pressure of the second step, is equal to or lower than the pressure of the first step. It is preferable that there be.
Specifically, the difference between the pressure in the second step and the pressure in the first step, that is, the value obtained by subtracting the pressure in the second step from the pressure in the first step, is preferably 0 MPaG or more and 0.05 MPaG or less. , more preferably 0.01 MPaG or more and 0.04 MPaG or less.
By setting the pressure difference between the first step and the second step within the above range, in the quench tower 2, the reaction by-products in the generated gas from the first step are promoted to condense and dissolve into the cooling water. As a result, the concentration of reaction by-products in the product gas flowing out from the quench tower 2 can be further reduced.

In the quench tower 2, a cleaning mechanism (not shown) intermittently performs a cleaning process in which cleaning water is sprayed onto the lowest gas-liquid contact member (not shown).

(cooling heat exchanger)
As the cooling heat exchanger 3, one capable of cooling the generated gas flowing out from the quench tower 2 to room temperature (10° C. or higher and 30° C. or lower) is appropriately used.
In the example shown in this figure, a gas inlet of the cooling heat exchanger 3 is connected to a pipe 104 whose one end is connected to a gas outlet of the quench tower 2, and a pipe 105 is connected to the gas outlet. ing.

The pressure of the cooling heat exchanger 3 in operation (specifically, the pressure at the gas outlet of the cooling heat exchanger 3) is the pressure of the quench tower 2 in operation (the gas outlet of the quench tower 2). It is preferable that the pressure is equal to the pressure of

In the cooled product gas discharged from the cooling heat exchanger 3, that is, the product gas cooled in the second step, the concentration of molecular nitrogen is preferably 60% by volume or more and 94% by volume or less, more preferably It is 70 volume % or more and 85 volume % or less. The concentration of butadiene is preferably 2% by volume or more and 15% by volume or less, more preferably 3% by volume or more and 10% by volume. Further, the concentration of water (steam) is preferably from 1% by volume to 30% by volume, more preferably from 1% by volume to 3% by volume. The concentration of ketone aldehydes is preferably 0% by volume or more and 0.3% by volume, more preferably 0.05% by volume or more and 0.25% by volume or less.
By keeping the concentration of each component in the cooled product gas in the second step within the above range, it is possible to improve the efficiency of butadiene purification in the next and subsequent steps, and to suppress side reactions that occur in the desolvation step. This makes it possible to further reduce energy consumption when producing butadiene.

<3rd process>
In the third step, the gas produced through the second step is separated into molecular oxygen and inert gases and other gases including 1,3-butadiene by selective absorption into an absorption solvent (crude separation). do. Here, "other gases containing 1,3-butadiene" refers to at least butadiene, 1-butene, and 2-butene (unreacted 1-butene and 2-butene) that are absorbed by the absorption solvent. Indicates the gas included.
In this third step, the product gas that has passed through the second step is separated by an absorption tower 4, as shown in FIG. Here, the absorption tower 4 is provided with a gas inlet at the bottom for introducing the generated gas that has undergone the second step, a solvent inlet for introducing the absorption solvent at the top, and a gas inlet at the bottom of the tower. (Specifically, other gases including 1,3-butadiene) are provided at the top of the column. , molecular oxygen, and inert gases). A pipe 105 whose one end is connected to the gas outlet of the heat exchanger 3 is connected to the gas inlet, a pipe 106 is connected to the solvent inlet, and a pipe 113 is connected to the solvent outlet. A pipe 107 is connected to the gas outlet.
To explain the third step in detail, the generated gas that has passed through the second step, that is, the generated gas that has flowed out from the heat exchanger 3, is fed to the absorption tower 4 via piping 105, and in synchronization with the absorption tower 4. The column 4 is supplied with an absorption solvent via a pipe 106. In this way, the absorption solvent is brought into countercurrent contact with the produced gas that has passed through the second step, and other gases containing 1,3-butadiene in the produced gas that has passed through the second step are selectively absorbed by the absorption solvent. This roughly separates other gases including 1,3-butadiene from molecular oxygen and inert gases. Then, the absorption solvent that has absorbed other gases including 1,3-butadiene flows out from the absorption tower 4 to the pipe 113, while the molecular oxygen and inert gases that were not absorbed by the absorption solvent are absorbed. It flows out from column 4 into pipe 107.

In the absorption tower 4 in operation, the temperature inside the absorption tower 4 is not particularly limited, but as the temperature inside the absorption tower 4 becomes higher, it becomes more difficult for molecular oxygen and inert gases to be absorbed by the absorption solvent. On the other hand, as the temperature inside the absorption tower 4 decreases, the absorption efficiency of hydrocarbons such as butadiene (other gases including 1,3-butadiene) into the absorption solvent increases, so the productivity of butadiene increases. In consideration of the above, the temperature is preferably 0°C or more and 60°C or less, more preferably 10°C or more and 50°C or less.

In addition, the pressure of the absorption tower 4 during operation (specifically, the pressure of the gas outlet of the absorption tower 4), that is, the pressure of the third step, is equal to or lower than the pressure of the second step. It is preferable that there be.
Specifically, the difference between the pressure in the third step and the pressure in the second step, that is, the value obtained by subtracting the pressure in the third step from the pressure in the second step, is preferably 0 MPaG or more and 0.05 MPaG or less. , more preferably 0.01 MPaG or more and 0.04 MPaG or less.
By setting the pressure difference between the second step and the third step within the above range, it is possible to promote the absorption of butadiene (other gases containing 1,3-butadiene) into the absorption solvent in the absorption tower 4. As a result, the amount of absorption solvent used can be reduced, and energy consumption can be reduced.

(absorbing solvent)
Examples of the absorption solvent include those containing an organic solvent as a main component. Here, "containing an organic solvent as a main component" indicates that the content of the organic solvent in the absorption solvent is 50% by mass or more.
Examples of organic solvents constituting the absorption solvent include aromatic compounds such as toluene, xylene and benzene, amide compounds such as dimethylformamide and N-methyl-2-pyrrolidone, sulfur compounds such as dimethylsulfoxide and sulfolane, acetonitrile and butyronitrile, etc. nitrile compounds, ketone compounds such as cyclohexanone and acetophenone, and the like.

The amount of absorption solvent to be used (supplied amount) is not particularly limited, but is 10 times or more by mass of the total flow rate (mass flow rate) of butadiene, 1-butene, and 2-butene in the generated gas that has passed through the second step. The amount is preferably 100 times by mass or less, more preferably 17 times by mass or more and 35 times by mass or less.
By controlling the amount of absorption solvent used within the above range, the absorption efficiency of other gases including 1,3-butadiene can be improved.
On the other hand, when the amount of absorption solvent used is excessive, the amount of energy consumed for purification for recycling the absorption solvent tends to increase. Furthermore, if the amount of absorption solvent used is too small, the absorption efficiency of other gases including 1,3-butadiene tends to decrease.

The temperature of the absorption solvent (temperature at the solvent inlet) is preferably from 0°C to 60°C, more preferably from 0°C to 40°C.
By setting the temperature of the absorption solvent within the above range, the absorption efficiency of other gases including 1,3-butadiene can be further improved.

<Circulation process>
In the circulation step, molecular oxygen and inert gases obtained in the third step are fed to the first step as reflux gas. In this circulation process, molecular oxygen and inert gases from the third process are processed by a solvent recovery column 5 and a compressor 6.
Specifically, the molecular oxygen and inert gases from the third step, that is, the molecular oxygen and inert gases discharged from the absorption tower 4, are sent to the solvent recovery tower 5 via the pipe 107. After being subjected to solvent removal treatment, it is sent to the compressor 6 via piping 110 and subjected to pressure adjustment treatment as necessary. The molecular oxygen and inert gases from the third step that have been subjected to the solvent removal treatment and pressure adjustment treatment in this manner flow out from the compressor 6 toward the reaction tower 1 and into the pipe 112.
In the example shown in this figure, while the molecular oxygen and inert gases flowing out from the solvent recovery tower 5 flow through the pipe 110, a part of the molecular oxygen and inert gases flow through the pipe 110. It is discarded via the communicating pipe 111. In this way, by providing the piping 111 for disposing of part of the molecular oxygen and inert gases flowing out from the solvent recovery tower 5, it is possible to adjust the amount of reflux gas supplied to the first step. can.

(solvent recovery tower)
The solvent recovery tower 5 is configured to remove the molecular oxygen and inert gases from the third step by washing them with water or a solvent. A gas inlet for introducing molecular oxygen and inert gases from the third step is provided in the center of the solvent recovery tower 5. A cleaning liquid inlet for introducing water or a solvent is provided at the upper part of the solvent recovery tower 5. A pipe 107 whose one end is connected to the gas outlet of the absorption tower 4 is connected to the gas inlet, and a pipe 108 is connected to the cleaning liquid inlet. Further, the solvent recovery tower 5 is provided with a gas outlet at the top thereof, through which molecular oxygen and inert gases washed with water or a solvent are led out. Further, at the bottom of the solvent recovery tower 5, a cleaning liquid outlet is provided for leading out the water or solvent used for cleaning the molecular oxygen and inert gases from the third step. A pipe 110 is connected to the gas outlet, and a pipe 109 is connected to the cleaning liquid outlet.

In this solvent recovery tower 5, the absorption solvent contained in the molecular oxygen and inert gases from the third step is removed, and the removed absorption solvent is used for cleaning together with the water or solvent used for cleaning. The liquid flows out from the liquid outlet into a pipe 109 and is collected via this pipe 109. Furthermore, the molecular oxygen and inert gases from the third step that have been subjected to the solvent removal treatment flow out from the gas outlet of the solvent recovery tower 5 to the pipe 110 .

Further, in the solvent recovery tower 5 in operation, the temperature inside the solvent recovery tower 5 is not particularly limited, but is preferably 0°C or more and 80°C or less, more preferably 10°C or more and 60°C or less. .

(compressor)
As the compressor 6, a compressor capable of pressurizing the molecular oxygen and inert gases from the solvent recovery column 5, if necessary, to the pressure required in the first step is appropriately used.
In the example shown in this figure, the compressor 6 has a gas inlet connected to a pipe 110 whose one end is connected to a gas outlet of the solvent recovery tower 5, and a gas outlet connected to a pipe 112. .

In this compressor 6, when the pressure in the third step is lower than the pressure in the first step, the pressure is increased by the pressure difference in accordance with the pressure difference between the third step and the first step.
When the pressure is increased in the compressor 6, the pressure increase is usually small, so the electrical energy consumption of the compressor remains small.

In the molecular oxygen and inert gases flowing out from the compressor 6, that is, the reflux gas, the concentration of molecular nitrogen is preferably 87% by volume or more and 97% by volume or less, more preferably 90% by volume or more and 95% by volume or less. volume% or less. Further, the concentration of molecular oxygen is preferably 1 volume% or more and 6 volume% or less, more preferably 2 volume% or more and 5 volume% or less.

<Desolution process>
In the desolvation step, the absorption solvent obtained in the third step that has absorbed other gases including 1,3-butadiene is subjected to a solvent separation treatment. That is, by separating the absorption solvent from the absorption solvent from the third step, a gas stream of the other gas comprising 1,3-butadiene, ie the gas comprising 1,3-butadiene, is obtained. In this desolvation step, as shown in FIG. 2, separation of other gases containing 1,3-butadiene from the absorption solvent is performed by the desolvation tower 7.
Specifically, the absorption solvent from the third step, that is, the absorption solvent that has absorbed other gases containing 1,3-butadiene that has flowed out from the absorption tower 4, is sent to the desolvation tower 7 via the pipe 113. It is sent and subjected to solvent separation treatment. Then, in the desolvation tower 7, other gases containing 1,3-butadiene and the absorption solvent are separated by distillation.

(Desoluting tower)
The desolvation tower 7 is configured to carry out solvent separation treatment by distilling and separating the absorbed solvent from the third step. A solvent inlet for introducing the absorption solvent from the third step is provided in the center of the desolvation tower 7. Furthermore, a gas outlet port is provided at the top of the desolvation tower 7 to lead out the gas containing 1,3-butadiene separated from the absorption solvent from the third step. A solvent outlet is provided at the bottom of the desolvation tower 7 to lead out the absorption solvent separated from the absorption solvent from the third step. A pipe 113 whose one end is connected to the solvent outlet of the absorption tower 4 is connected to the solvent inlet, a pipe 115 is connected to the gas outlet, and a pipe 114 is connected to the solvent outlet. has been done.

In this desolvation tower 7, the gas containing 1,3-butadiene and the absorption solvent separated from the absorption solvent from the third step are separated, and the gas containing 1,3-butadiene is piped from the gas outlet. 115 , and the absorption solvent flows out from the solvent outlet into pipe 114 .

The pressure inside the desolvation tower 7 is not particularly limited, but is preferably 0.03 MPaG or more and 1.0 MPaG or less, more preferably 0.2 MPaG or more and 0.6 MPaG or less.

Further, in the desoluting tower 7 in operation, the temperature at the bottom of the desoluting tower 7 is preferably 80°C or more and 1900°C or less, more preferably 100°C or more and 180°C or less.

According to such a method for producing 1,3-butadiene, in the quench tower 2, a cleaning process is performed in which cleaning water is supplied to the gas-liquid contacting member at the lowest stage, so that the second stage for cooling the produced gas is performed. Since the process can be carried out stably over a long period of time, 1,3-butadiene can be produced with high time efficiency.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

[Example 1]
1,3-butadiene is extracted from the raw material gas containing 1-butene and 2-butene by going through the following first step, second step, third step, desolvation step, and circulation step according to the flow diagram in Figure 2. , was produced continuously for 500 hours.
Further, the raw material gas used contained 1-butene and 2-butene, and the proportion of 2-butene was 87% by volume relative to the total of 100% by volume of 1-butene and 2-butene.

(1st step)
A reactor 1 (inner diameter 21.2 mm, outer diameter 25.4 mm) filled with a metal oxide catalyst so that the catalyst layer length was 4000 mm was charged with a volume ratio (1-butene and 2-butene/O ₂ /N ₂ /H ₂ O) of 1/1.5/16.3/1.2 is supplied at a GHSV of 2000 h ^-1 , and the raw material gas and molecular oxygen are By subjecting the contained gas to an oxidative dehydrogenation reaction, a product gas containing 1,3-butadiene was obtained. The pressure in this first step, that is, the pressure at the gas inlet of reactor 1, was 0.1 MPaG. Here, the actual volume GHSV of the mixed gas was 2150 h ^-1 .
In this first step, as the metal oxide catalyst, an oxide represented by the compositional formula Mo ₁₂ Bi ₅ Fe _0.5 Ni ₂ Co ₃ K _0.1 Cs _0.1 Sb _0.2 was added to spherical silica at a rate of 20% of the total catalyst volume. The material supported by the above was used.
The mixed gas is a mixture of raw material gas and reflux gas (molecular oxygen and inert gases), and air as a molecular oxygen-containing gas, molecular nitrogen as an inert gas, and The composition is adjusted by further mixing water (steam).

(Second process)
As the quench tower 2, one with the following specifications was used.
Total length of tower body 20: 780cm
Inner diameter of tower body 20: 15.24cm
Gas-liquid contact member 30: Irregular packing (cascade mini ring)
Number of gas-liquid contact members 30: 5
Ratio between spray distance L and spray width D by the jet head 41 (L/D): 1.6

The product gas discharged from the reactor 1 was brought into countercurrent contact with cooling water in the quench tower 2 to be rapidly cooled to 76°C, and then cooled to 30°C in the cooling heat exchanger 3. The amount of cooling water supplied is 1 L/min. The pressure in this second step, that is, the pressure at the gas outlet of the quench tower 2 was 0.1 MPaG, and the pressure at the gas outlet of the cooling heat exchanger 3 was also 0.1 MPaG.
Then, in the quench tower 2, the cleaning mechanism was driven under the following conditions every 8 hours after the cooling process of the produced gas.
Cleaning water supply amount from jet head 41: 0.002L/min
Amount of cleaning water supplied per unit area of the surface of the gas-liquid contact member 30: 55 L/m ²
Amount of cleaning water used for one cleaning process for the gas-liquid contact member 30: 1L

(Third step)
The generated gas flowing out from the heat exchanger 3 (hereinafter also referred to as "cooled generated gas") is transferred to an absorption tower 4 (outer diameter 152.4 mm, height 7800 mm, material SUS304) with a regular packing arranged inside. It was supplied from the lower gas inlet, and from the upper solvent inlet of the absorption tower 4, an absorption solvent containing 95% by mass or more of toluene was supplied at 10°C. The amount of absorption solvent supplied was 33 times the total flow rate (mass flow rate) of butadiene, 1-butene, and 2-butene in the cooled product gas. The pressure in this third step, that is, the pressure at the gas outlet of the absorption tower 4, was 0.1 MPaG.

(circulation process)
The gas discharged from the absorption tower 4 was washed with water or a solvent in the solvent recovery tower 5 to remove a small amount of absorption solvent contained in the gas. The gas from which the absorption solvent was removed in this way flowed out of the solvent recovery tower 5, a part of which was discarded, and most of the remaining part was sent to the compressor 6. Then, in the compressor 6, the pressure of the gas from the solvent recovery tower 5 was increased by pressure adjustment processing. The absorbing solvent was thus removed and the pressurized gas exited the compressor 6 and was refluxed to the reactor 1.

(Desolution process)
The liquid discharged from the absorption tower 4 was supplied to the desolvation tower 7, and the gas discharged from the main body of the desolvation tower was cooled in a condenser to obtain a gas containing 1,3-butadiene. In addition, a part of the liquid discharged from the desolvation tower body was heated in a reboiler to obtain an effluent, that is, an absorption solvent (hereinafter also referred to as "circulated absorption solvent"). In this manner, the gas containing 1,3-butadiene and the circulating absorption solvent were separated by distillation in the desoluting tower 7.

[Comparative example 1]
In the second step, 1,3-butadiene was extracted from the raw material gas containing 1-butene and 2-butene for 127.5 hours in the same manner as in Example 1 except that the cleaning mechanism of the quench tower 2 was not driven. Manufactured continuously.

In Example 1 and Comparative Example 1, after the production of 1,3-butadiene was completed, the lowest stage gas-liquid contacting member 30 in the quench tower 2 was examined, and in Example 1, a small amount of solid components were attached. On the other hand, in Comparative Example 1, it was confirmed that a large amount of solid components were attached.
Further, when the waste water from the quench tower 2 was examined, a large amount of solid components were found in Example 1, and a small amount of solid components was found in Comparative Example 1.
From the above, according to Example 1, a large amount of solid components precipitated by cooling is prevented or suppressed from adhering to the gas-liquid contact member 30, and as a result, cooling of the generated gas is stabilized over a long period of time. It is understood that it is possible to perform the

1 Reactor 2 Quenching tower 3 Heat exchanger 4 Absorption tower 5 Solvent recovery tower 6 Compressor 7 Desolvation tower 20 Tower body 21 Surrounding wall 22 Tower top 23 Tower bottom 25 Gas inlet 26 Gas outlet 27 Cooling water outlet 30 Gas-liquid contact member 35 Cooling water supply mechanism 36 Spray head 40 Cleaning mechanism 41 Spray head 100 to 116 Piping

Claims (5)

In a quench tower that is equipped with a gas-liquid contacting member inside and in which the gas to be cooled supplied from the lower part of the tower is cooled by cooling water supplied from the upper part of the tower,
The cooled gas precipitates solid components that adhere to the gas-liquid contact member by being cooled,
a cleaning mechanism that supplies cleaning water to the gas-liquid contact member;
The cleaning mechanism includes a jetting head that sprays cleaning water to the gas-liquid contacting member at the lowest stage,
A quench tower characterized in that a supply amount of the washing water in the washing mechanism is 861 to 1076 L/min. A plurality of the gas-liquid contacting members are arranged in a column so as to overlap each other vertically with a space therebetween, and the cleaning mechanism supplies cleaning water to the lowest stage gas-liquid contacting member from above. The quench tower according to claim 1, characterized in that: The quench tower according to claim 1 or 2, wherein the cleaning mechanism includes a jetting head that jets cleaning water to the gas-liquid contacting member. The quench tower according to any one of claims 1 to 3, wherein the cleaning mechanism is driven when specified. A gas cooling method for cooling a gas to be cooled supplied from the lower part of the tower with cooling water supplied from the upper part of the tower in a quench tower equipped with a gas-liquid contact member, the method comprising:
The cooled gas precipitates solid components that adhere to the gas-liquid contact member by being cooled,
Supplying cleaning water by jet to the gas-liquid contacting member at the lowest stage,
A gas cooling method characterized in that cleaning water is supplied to the gas-liquid contacting member at a supply rate of 861 to 1076 L/min.

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