WO2012090690A1 - Method for purifying acrylonitrile - Google Patents
Method for purifying acrylonitrile Download PDFInfo
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- WO2012090690A1 WO2012090690A1 PCT/JP2011/078706 JP2011078706W WO2012090690A1 WO 2012090690 A1 WO2012090690 A1 WO 2012090690A1 JP 2011078706 W JP2011078706 W JP 2011078706W WO 2012090690 A1 WO2012090690 A1 WO 2012090690A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
- B01D3/4205—Reflux ratio control splitter
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/24—Preparation of carboxylic acid nitriles by ammoxidation of hydrocarbons or substituted hydrocarbons
- C07C253/26—Preparation of carboxylic acid nitriles by ammoxidation of hydrocarbons or substituted hydrocarbons containing carbon-to-carbon multiple bonds, e.g. unsaturated aldehydes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
- B01D3/4211—Regulation; Control of columns
- B01D3/4216—Head stream
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/32—Separation; Purification; Stabilisation; Use of additives
- C07C253/34—Separation; Purification
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
- C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
- C07C255/06—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms of an acyclic and unsaturated carbon skeleton
- C07C255/07—Mononitriles
- C07C255/08—Acrylonitrile; Methacrylonitrile
Definitions
- the present invention relates to a method for purifying acrylonitrile by distilling a solution containing acrylonitrile, hydrogen cyanide and water.
- reaction product gas containing acrylonitrile, acetonitrile and hydrogen cyanide is cooled in a quenching tower and unreacted.
- the ammonia is neutralized and removed with sulfuric acid.
- the reaction product gas is sent to an absorption tower to absorb acrylonitrile, acetonitrile and hydrogen cyanide in water.
- Patent Document 1 discloses a method of suppressing the polymerization of acrylonitrile and hydrogen cyanide by adding an acid and hydroquinone to a dehydride dehydration tower in the purification of acrylonitrile.
- a solution containing acrylonitrile, hydrogen cyanide and water is distilled, a vapor containing hydrogen cyanide is distilled from the top of the tower, and a solution containing acrylonitrile is withdrawn from the bottom of the tower.
- the gas containing hydrogen cyanide distilled from the top of the column is cooled and fractionated by a condenser, and the hydrogen cyanide with less impurities that has not been condensed is used as a raw material for the hydrogen cyanide derivative. It is preferred to keep the acrylonitrile concentration low.
- the problem to be solved by the present invention is to provide a method for stabilizing product quality in an acrylonitrile manufacturing process.
- the present inventor stabilizes the product quality by controlling the temperature of a specific stage of the distillation column in the process of distilling the solution containing acrylonitrile, hydrogen cyanide and water in the process of producing acrylonitrile.
- the present inventors have found that the process load can be reduced and completed the present invention.
- a method for purifying acrylonitrile comprising a step of distilling a solution containing acrylonitrile, hydrogen cyanide and water using a distillation apparatus having a distillation column and a condenser for the top gas connected to the distillation column, A method comprising a step of maintaining a constant temperature of a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column.
- a regulating valve is provided in a pipe for supplying the refrigerant to the condenser and / or a pipe for discharging the refrigerant from the condenser, and a thermometer is provided in the temperature control stage, Set the target temperature of the temperature control stage, When the temperature of the temperature control stage is higher than the target temperature, the opening of the adjustment valve is adjusted to increase the supply amount of the refrigerant, [1] The above [1], wherein when the temperature of the temperature control stage is lower than the target temperature, the temperature of the temperature control stage is kept constant by adjusting the opening of the regulating valve to reduce the supply amount of the refrigerant. the method of.
- the heat removal amount of the condenser is increased or decreased, In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column; Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage, A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is lower than the hydrogen cyanide concentration, the lowest stage (bottom stage) is temperature controlled.
- the heat removal amount of the condenser is increased or decreased, In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column; Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage, A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is higher than the hydrogen cyanide concentration, and the uppermost stage (top stage) is temperature controlled.
- a distillation tower A thermometer provided in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column; A condenser connected to the distillation column; A pipe for supplying a refrigerant and a pipe for discharging the refrigerant connected to the condenser;
- a distillation apparatus comprising: a pipe for supplying the refrigerant and / or an adjustment valve for adjusting a supply amount of the refrigerant attached to the pipe for discharging the refrigerant, The thermometer is connected to the regulating valve via a temperature controller, The temperature of the temperature control stage is transmitted to the temperature controller by the thermometer, When the temperature of the temperature control stage is higher than the target temperature by the temperature controller, the supply amount of the refrigerant is increased by adjusting the opening of the adjustment valve, A distillation apparatus in which when the temperature of the temperature control stage is lower than a target temperature, the amount of refrigerant supplied is reduced by adjusting the opening of the regulating valve.
- a high-quality product can be stably obtained over a long period of time in the acrylonitrile manufacturing process.
- the purification method of acrylonitrile of this embodiment is: A method for purifying acrylonitrile, comprising a step of distilling a solution containing acrylonitrile, hydrogen cyanide and water using a distillation apparatus having a distillation column and a condenser for the top gas connected to the distillation column, The method includes a step of maintaining a constant temperature in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column.
- FIG. 1 is a schematic diagram schematically showing an example of an acrylonitrile production process
- FIG. 2 is a schematic diagram conceptually showing an example of a dehydrating acid dehydration tower and equipment connected thereto.
- the “distillation tower” in the present embodiment will be described as a “debleaching acid dehydration tower”.
- the “distillation tower” is not limited to the “debleaching acid dehydration tower”, and may be any tower capable of performing distillation. Are all included in the range of the “distillation tower” of the present embodiment.
- the liquid at the bottom of the absorption tower 9 is supplied from the line 10 to the recovery tower 12. Extracted water is introduced from the line 15 to the top of the recovery tower 12, and acetonitrile is extracted and separated by extractive distillation. Acetonitrile is extracted from the line 16 to the outside of the process system. Most of the water is extracted from the line 13 to the outside of the process system. From the top of the recovery tower, acrylonitrile, hydrogen cyanide and water are distilled off by a line 17 and condensed by a condenser not shown, and then separated into two layers of an organic layer and an aqueous layer by a decanter not shown. An organic layer containing acrylonitrile, hydrogen cyanide and a small amount of water is supplied to the dehydride dehydration tower 18. The water layer is recycled to the previous step as a recovery tower feed liquid (from line 10) or extracted water (from line 15).
- Vapor containing hydrogen cyanide is distilled from the top of the dehydrating acid dehydration tower 18 through the line 19 and sent to the condenser 20 to be cooled and contracted.
- the condensed hydrogen cyanide liquid is refluxed to the top of the column by a line 22, and crude hydrogen cyanide gas with little impurities that has not been condensed is drawn out of the system from the line 21.
- the crude hydrogen cyanide gas is purified by a distillation column (not shown) as necessary and used as a raw material for the hydrogen cyanide derivative.
- the condenser 20 is preferably a vertical type, and acetic acid is sprayed on the upper tube sheet to suppress hydrogen cyanide polymerization.
- water or an aqueous methanol solution having a supply temperature of 0 to 35 ° C., preferably 3 to 30 ° C. is used.
- the liquid in the tower is extracted from the chimney tray D in the middle stage of the dehydrating acid dehydration tower 18 by the line 23, cooled by the refrigerant 23a by the side cut cooler 23b, supplied to the decanter 23d by the line 23c, and the organic layer and the water layer by the decanter 23d. Separate into two layers.
- the “middle stage” indicates a portion below the tower top and above the tower bottom, and in the case of a multistage distillation tower, indicates one stage between the tower bottom and the tower top.
- the line 23 is preferably set to 20 to 30 plates from the bottom of the column from the viewpoint of efficiently separating water from the crude acrylonitrile.
- the same refrigerant as the refrigerant 20a can be used.
- the amount of heat removed by the side cut cooler 23b is adjusted with reference to a thermometer (not shown) for measuring the temperature of the liquid installed in the decanter 23d.
- the liquid temperature in the decanter is preferably controlled to be constant in the range of 20 to 40 ° C.
- the aqueous layer in the decanter is recycled to a pre-process such as the recovery tower 12 through the line 23f.
- the organic layer in the decanter is returned to the lower stage by the line 23e from the stage from which the liquid in the tower is extracted. This organic layer may be preheated back.
- the heat required for distillation is supplied from the reboiler 24a through the line 24c.
- As the heat medium 24b steam or high-temperature process water taken out from the tower bottom (lines 14 and 15) and / or the tower bottom (line 13) of the recovery tower 12 is used.
- the amount of heat given to the distillation column by the reboiler 24a is preferably 180 ⁇ 10 3 to 260 ⁇ 10 3 kcal / h / t-acrylonitrile, and is preferably 190 ⁇ 10 3 from the viewpoint of efficiently separating and recovering acrylonitrile in the deblue acid dehydration column 18. ⁇ 230 ⁇ 10 3 kcal / h / t-acrylonitrile is more preferred.
- the mass of acrylonitrile is the mass (t) of acrylonitrile obtained as a product from the product tower, and the above-mentioned numerical value represents the calorie per unit mass of acrylonitrile. Can do.
- Crude acrylonitrile is extracted from the bottom of the dehydration acid dehydration tower 18 through the line 24 and sent to the product tower 25. A part of the column bottom liquid extracted by the line 24 is supplied to the reboiler 24a.
- the product column 25 is a plate distillation column operated under a pressure lower than atmospheric pressure.
- the distillate vapor from the product column 25 is withdrawn through a line 26 and sent to a condenser 30 for condensation.
- the condensed liquid is refluxed to the product column 25 through the line 31, and a part of the liquid is extracted through the line 29.
- the column bottom liquid containing the high boiling point substance is extracted from the line 28.
- acrylonitrile is obtained as a product from line 27.
- the amount of acrylonitrile produced may be increased or decreased due to production plans, even during normal operation.
- the amount of the solution fed to the dehydrating acid dehydration tower 18 is increased or decreased, and it becomes necessary to adjust the operating conditions of the distillation apparatus.
- the “distillation apparatus” is a concept including ancillary equipment of a distillation column such as a reboiler and a condenser. A part of the solution is extracted from the middle stage of the distillation column, and the middle stage extracted liquid is cooled.
- a cooler and / or oil-water separator is also included in the distillation apparatus.
- the dehydrocyanic acid dehydration tower 18 is a tray distillation tower operated under normal pressure, and the number of shelves is preferably 50 to 65.
- the shelves to be used include types such as a sheave tray and a dual flow tray, but are not limited thereto.
- the feed liquid to the dehydrating acid dehydration tower is supplied to the feed stage A from the line 17.
- the position of the feed stage A is the upper part of the chimney tray D, preferably the upper part of the 10 to 25 stages of the chimney tray D.
- the distillate vapor is sent to the condenser 20 and cooled to be condensed.
- the condensed hydrogen cyanide liquid is refluxed to the uppermost stage C of the tower through a line 22, and crude hydrogen cyanide gas with little impurities, which has not been condensed, is drawn out of the system from the line 21. Distillation purification is performed by bringing the reflux liquid flowing down the column into contact with the vapor rising in the column.
- the temperature of the stage B located above the feed stage A and below the uppermost stage C of the tower is kept constant.
- “above feed stage A” does not include feed stage A itself
- “below uppermost stage C” does not include uppermost stage C itself.
- “maintaining the temperature constant” means maintaining the set target temperature, and when setting an upper limit value and a lower limit value, which will be described later, a temperature not lower than the upper limit value and not higher than the lower limit value. It also includes maintaining the range. It also includes the amplitude due to hunting of instrument measurements.
- stage B does not mean all stages located above the feed stage A and below the top stage of the tower, but refers to a specific stage where a thermometer 22b selected from the stages in between is installed. , Called “temperature control stage”. More preferably, the temperature of a specific stage B located between the upper three stages from the feed stage A to the lower three stages from the uppermost stage of the tower is kept constant.
- the target temperature is preferably set at a specific temperature. However, in practice, even when the temperature of the temperature control stage deviates from the target temperature, the distillation at the target temperature is acceptable in terms of distillation separation.
- the thermometer 22b is connected to a flow rate control valve 20b of the refrigerant 20a provided in a pipe for discharging the refrigerant via the temperature controller 22a, and the temperature of the temperature control stage B is controlled by the thermometer 22b. 22a, when the temperature of the temperature control stage B is higher than the target temperature, the supply amount of the refrigerant is increased by adjusting the opening of the regulating valve 20b, and the temperature of the temperature control stage B is higher than the target temperature. When it is low, the supply amount of the refrigerant is decreased by adjusting the opening degree of the regulating valve 20b.
- adjusting the opening degree of the adjusting valve
- a mode in which the opening degree is increased, that is, the valve is opened and a mode in which the opening degree is decreased, that is, the valve is closed.
- the adjustment valve is provided in the discharge pipe as in the example shown in FIG. 2, the refrigerant 20 a is discharged by opening the adjustment valve 20 b, and the refrigerant having a lower temperature than the discharged refrigerant flows into the condenser 20. As a result, the cooling effect of the condenser 20 is enhanced.
- the regulating valve 20b by closing the regulating valve 20b, the discharge of the refrigerant 20a is suppressed, and the refrigerant having a lower temperature than the discharged refrigerant is prevented from flowing into the condenser 20, so that the cooling effect of the condenser 20 is reduced.
- the temperature of the reflux liquid returned to the tower from the condenser 20 is changed by changing the supply amount of the refrigerant 20a by the control valve 20b, and the temperature of the temperature control stage B is kept constant.
- the supply amount of the refrigerant can be adjusted by the adjusting valve so that the temperature of the temperature control stage changes between the lower limit value and the upper limit value. .
- the target temperature of the temperature control stage B is preferably 40 to 55 ° C. from the viewpoint of lowering the acrylonitrile concentration in the distillate vapor to increase the hydrogen cyanide purity and from the viewpoint of lowering the hydrogen cyanide concentration in the bottom liquid and increasing the acrylonitrile purity. More preferred is ⁇ 50 ° C.
- the concentration of acrylonitrile in the distillate vapor increases, leading to loss of acrylonitrile, and the purity of distillate hydrogen cyanide is lowered, which adversely affects the quality of the hydrogen cyanide derivative.
- the concentration of hydrogen cyanide in the column bottom liquid rises and cannot be sufficiently removed by the downstream product column, and the acrylonitrile product may become an off-spec product.
- the “target temperature” is an optimum temperature derived from an acrylonitrile distillation experiment in a laboratory and / or an experiment on temperature dependence of distillation separation performance using a commercial scale distillation apparatus.
- temperature profile the relationship between each temperature distribution from the top of the distillation column to the bottom of the column (hereinafter referred to as “temperature profile”), the concentration of the key substance at the top and the concentration of the key substance at the bottom is examined.
- the key substance is a substance that serves as a guideline for carrying out distillation separation, and generally refers to a trace amount of impurities. If a large amount of the substance is mixed, it is not preferable for purification. It is preferable that a specification of the key substance concentration is determined, and this is used as a separation specification and used for operation management of the distillation column.
- FIG. 3 is a schematic diagram showing another example of the dehydration acid dehydration tower 18 and equipment connected thereto. Since the flow rate adjustment valve 20b 'connecting the supply pipe and the discharge pipe for the refrigerant 20a of the condenser is substantially the same as the example shown in FIG. 2, only the differences will be described. When the control valve 20b 'is opened, a part of the refrigerant 20a flows from the supply pipe to the discharge pipe without passing through the condenser, so that the supply amount of the refrigerant 20a is reduced by opening the control valve 20b'.
- the thermometer 22b is connected to the flow rate control valves 20b and 20b ′ via the temperature controller 22a, the temperature of the temperature control stage B is transmitted to the temperature controller 22a, and the temperature of the temperature control stage B is the target temperature. If higher, the regulating valve 20b is opened and / or the regulating valve 20b 'is closed to increase the supply amount of the refrigerant 20a. When the temperature of the temperature control stage B is lower than the target temperature, the regulating valve 20b is closed and / or the regulating valve 20b ′ is opened to reduce the supply amount of the refrigerant 20a, and the temperature of the temperature control stage B is kept constant. To maintain.
- both the flow rate control valves 20b and 20b ′ are operated by a command from the temperature controller 22a.
- Both of them need not be opened / closed by the temperature controller 22a, only the flow rate control valve 20b may be opened / closed by the temperature controller 22a, and the flow rate control valve 20b ′ may be manually operated.
- the opening degree of the control valve 20b ′ is kept constant, and the temperature of the temperature control stage B is kept constant by operating the control valve 20b as in the example shown in FIG. .
- acrylonitrile is used as the key material at the top of the column and hydrogen cyanide and water as the key material at the bottom.
- Hydrogen cyanide is also one of commercially available products and is used in various hydrogen cyanide derivatives.
- methacrylic acid obtained by the acetone cyanohydrin (ACH) method is used.
- MMA methyl acid
- acrylonitrile is distilled off from the top of the column, it is possible to increase the purity of hydrogen cyanide by further separation by distillation or the like. Processing equipment is also an essential requirement. Therefore, considering the use of hydrogen cyanide, it is preferable to keep the concentration of acrylonitrile in the hydrogen cyanide distilled from the top of the column low.
- the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the column is preferably 1000 ppm or less, more preferably 700 ppm or less, and even more preferably 500 ppm or less.
- the hydrogen cyanide concentration in acrylonitrile extracted from the column bottom is preferably 100 ppm or less, more preferably 70 ppm or less, and further preferably 50 ppm or less.
- the reboiler heating amount and the condenser heat removal amount are made constant, and the concentration (mass%) of the key substance is examined in each stage (concentration profile).
- concentration profile concentration profile
- temperature profile temperature profile
- the temperature of each stage located below the uppermost stage may be different, and at this time, a difference occurs in the key substance concentration at the top and bottom of each case. That is, even if only the temperature of the feed stage and / or the uppermost stage is monitored, the concentration of the key substance at the top and the bottom of the tower cannot be controlled.
- the present inventor has discovered that the temperature change in the stage located above the feed stage and below the top stage affects the key substance concentration.
- the temperature at the top and the bottom of the column is reversed, specifically, the temperature of the lowest level (the lowest level) among the levels where the acrylonitrile concentration is lower than the hydrogen cyanide concentration, and / or Of the stages where the acrylonitrile concentration is higher than the hydrogen cyanide concentration, the uppermost stage (the uppermost stage) was found to show a strong correlation with the concentration of the key substance at the top and / or bottom of the tower. Since acrylonitrile is highly concentrated at the bottom of the column and hydrogen cyanide is highly concentrated at the top of the column, the concentration of both is reversed at a certain stage. The temperature of this stage affects the concentration of the key substance at the top and / or bottom of the tower.
- the target temperature can be set from the temperature of the temperature control stage in the preferred temperature profile.
- the temperature of the temperature control stage shows a rapid change, and the inflection point of the temperature profile often corresponds to the temperature control stage.
- the heat removal amount of the condenser is increased or decreased, In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column; Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage, A stage located above the feed stage of the distillation column and below the top stage of the distillation column, wherein the acrylonitrile concentration is lower than the hydrogen cyanide concentration, the lowest stage (bottom stage) and / or the stage Among the stages where the acrylonitrile concentration is higher than the hydrogen cyanide concentration, the uppermost stage (the uppermost stage) is set as the temperature control stage, Determining the target temperature of the temperature control stage so that the concentration of acrylonitrile distilled from the top of the distillation column is minimized from the temperature of each stage in each heat removal amount.
- the reboiler heating amount and the condenser heat removal amount are repeated in parallel, but in the final adjustment stage, the reboiler heating amount and the condenser heat removal amount are referred to as If the two heat quantity variables are increased or decreased at a time, it becomes difficult to operate the distillation column stably. Therefore, from the viewpoint of determining the position of the temperature control stage and the target temperature while stably operating the distillation column, the reboiler has a constant heating amount in the range of 180 ⁇ 10 3 to 260 ⁇ 10 3 kcal / h / t-acrylonitrile.
- the heat removal amount of the condenser is increased or decreased and the temperature of the temperature control stage of the distillation column becomes the target temperature.
- the amount of acrylonitrile produced may be increased or decreased due to production plans, even during normal operation.
- the amount of the solution fed to the dehydrating acid dehydration tower 18 is increased or decreased.
- the amount of product produced according to the change in the mass of the feed liquid and the amount of heat added to the reboiler from the above-described reboiler calorific value (hereinafter referred to as “reboiler heating amount”) are adjusted and changed.
- the reboiler heating amount is increased or decreased, the amount of steam inside the distillation column changes.
- acrylonitrile may be cooked in the upper part of the tower and the proportion of distilling in the crude hydrogen cyanide may be increased.
- hydrogen cyanide may fall to the lower part of the tower, and the ratio existing in the bottom extract may rise. All of these adversely affect the purity of the product (acrylonitrile, hydrogen cyanide derivative). In order to prevent these, it is useful to appropriately adjust the distillation tower temperature in accordance with the amount of increase / decrease in the reboiler heating amount.
- a distillation tower A thermometer provided in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column; A condenser connected to the distillation column; A pipe for supplying a refrigerant and a pipe for discharging the refrigerant connected to the condenser;
- a distillation apparatus comprising: a pipe for supplying the refrigerant and / or an adjustment valve for adjusting a supply amount of the refrigerant attached to the pipe for discharging the refrigerant,
- the thermometer is connected to the regulating valve via a temperature controller, The temperature of the temperature control stage is transmitted to the temperature controller by the thermometer, When the temperature of the temperature control stage exceeds the target temperature by the temperature controller, the supply amount of the refrigerant is increased by adjusting the opening of the adjustment valve, and the temperature of the temperature control stage is less than the target temperature
- the present embodiment will be described in more detail with reference to examples.
- the acrylonitrile manufacturing process in an Example is the same as that of what was shown in FIG.
- the dehydrating acid dehydration tower in the examples is the same as that shown in FIG.
- Analysis of acrylonitrile was performed by gas chromatography using the following apparatus and conditions. In the gas chromatography, Shimadzu GC-17A was used as an apparatus, and TC-FFAP 60 m ⁇ 0.32 film thickness 0.25 ⁇ m was used as a column. The detector used was FID and the carrier gas used helium.
- the column temperature conditions were as follows.
- Hydrogen cyanide and water were analyzed by silver nitrate titration method and Karl Fischer method, respectively.
- Flow meter YKOGAWA differential pressure flow meter (orifice type) Differential Pressure Transmitter DP hard EJX Thermometer: Resistance Thermometer, Temperature Trans made by OKAZAKI
- Example 1 Propylene, ammonia and air were supplied to a vertical cylindrical fluidized bed reactor 1 having an inner diameter of 8 m and a length of 20 m, and propylene ammoxidation reaction was carried out as follows.
- the fluidized bed reactor 1 had a raw material gas dispersion pipe, a dispersion plate, a heat removal pipe, and a cyclone inside.
- the dehydrating acid dehydration tower 18 comprises 55 sheave trays, has a feed stage A at the 37th stage from the bottom of the tower, a chimney tray D at the 24th stage, and a line 23 for extracting a side cut flow at the 24th stage.
- the 23rd stage had a line 23e for returning the organic layer in the decanter.
- a molybdenum-bismuth-iron-based supported catalyst having a particle size of 10 to 100 ⁇ m and an average particle size of 55 ⁇ m was used and packed so as to have a stationary bed height of 2.7 m.
- Air was 56000Nm 3 / h supplied from the air distribution plate, propylene 6200Nm 3 / h and ammonia from a raw material gas dispersion tube was 6600Nm 3 / h feed.
- the reaction temperature was controlled with a heat removal tube so as to be 440 ° C.
- the pressure was 0.70 kg / cm 2 G.
- the reaction product gas was introduced into the quenching tower 6 and brought into countercurrent contact with water, and unreacted ammonia was neutralized and removed with sulfuric acid.
- the gas flowing out of the quenching tower 6 was introduced into the absorption tower 9 from the line 8. Absorbed water was introduced from the line 14 at the top of the absorption tower 9 and brought into countercurrent contact with the gas, so that acrylonitrile, acetonitrile and hydrogen cyanide in the gas were absorbed into water.
- the amount of absorbed water was adjusted so that the acrylonitrile concentration in the gas discharged from the top of the absorption tower was 100 volppm.
- the gas that was not absorbed was taken out from the absorption tower top line 11 and incinerated.
- the absorption tower bottom liquid was preheated to 80 ° C. and supplied to the recovery tower 12. Acetonitrile and most of the water were separated in the recovery tower 12, and acrylonitrile, hydrogen cyanide and water were distilled from the tower top line 17.
- the distillate vapor is condensed, an organic layer and an aqueous layer are formed by a recovery tower decanter (not shown), the aqueous layer is recycled to the supply line 10 of the recovery tower 12, and the organic layer is supplied to the dehydride dehydration tower 18. .
- the mass and temperature of the feed liquid to the dehydrating acid dehydration tower 18 were measured by a flow meter and a thermometer (not shown) installed in the line 17.
- the measured values were 13595 kg / h and 35.0 ° C., respectively.
- Crude hydrogen cyanide gas was extracted from the top line 19 of the dehydrating acid dehydration tower 18 and sent to the condenser 20, where it was cooled and fractionated.
- the refrigerant 20a used in the condenser 20 was 6 ° C. water.
- the condensed hydrogen cyanide liquid was refluxed to the top of the column, and hydrogen cyanide gas with little impurities that was not condensed was extracted from the line 21 to the outside of the system.
- the liquid in the tower was extracted from the 24th stage of the dehydration acid dehydration tower 18 and cooled by the side cut cooler 23b.
- the refrigerant 23a used for the side cut cooler 23b was 25 ° C. water.
- the heat removal amount Q3 of the side cut cooler was adjusted by the flow rate of the refrigerant 23a so that the liquid temperature of the decanter 23d was 30 ° C.
- the side stream extracted from the tower was separated into two layers of an organic layer and an aqueous layer by a decanter 23d, and the aqueous layer was extracted through a line 23f and recycled to the supply liquid of the recovery tower 12.
- the organic layer was returned to the 23rd stage of the tower by line 23e. 110 ° C. process water extracted from the lower part of the recovery tower 12 was used as a heat source for the reboiler 24a.
- the amount of heat Q1 applied was 200 ⁇ 10 3 kcal / h / t-acrylonitrile, and the mass of acrylonitrile obtained as a product in the product tower 25 was 11.5 t per hour, so 2300 ⁇ 10 3 kcal / h
- the flow rate of the process water 24b leading to the reboiler 24a was adjusted.
- Crude acrylonitrile was extracted from the tower bottom line 24 and sent to the product tower 25.
- the bottom extract liquid was measured for mass by a flow meter (not shown) installed in the line 24, and the measured value was 11,585 kg / h.
- the temperature of the liquid extracted from the bottom of the tower was 86 ° C., which was the same as the liquid temperature at the bottom of the dehydration acid dehydration tower 18.
- the heating amount of the reboiler 24a and the heat removal amount of the condenser 20 were made constant, and the acrylonitrile concentration and the hydrogen cyanide concentration in each stage above the feed stage were measured.
- the lower stage was 51 stages from the tower bottom.
- the temperature of the stage is 48 ° C. there were.
- the stage is the temperature control stage B
- the thermometer installed in the stage is the thermometer 22b
- the target temperature of the stage is 48 ° C.
- the heat removal amount of the condenser is set so that the temperature of the stage is 48 ° C. It was adjusted. The above operation was continued for about 6 months when the acrylonitrile production amount was 11.5 ⁇ 0.2 t / h.
- the temperature of the temperature control stage was 48 ⁇ 0.4 ° C.
- the dehydrating acid dehydration tower can be operated stably.
- the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ⁇ 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ⁇ 10 ppm. Met.
- the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained.
- the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
- Example 2 Acrylonitrile was produced using the same equipment and method as in Example 1 except that the production amount of acrylonitrile was increased to 12.7 t / h by changing the production plan.
- the reboiler heat was increased to 2540 ⁇ 10 3 kcal / h.
- the flow rate control valve 20b of the refrigerant 20a was controlled through the temperature controller 22a so that the temperature of the temperature control stage B of the dehydration acid dehydration tower 18 was 48 ° C.
- Each temperature in the dehydrating acid dehydration tower 18 and the temperature of the decanter 23d were substantially the same as those in Example 1. The above operation was continued for about 3 months when the acrylonitrile production amount was 12.7 ⁇ 0.2 t / h.
- the temperature of the temperature control stage was 48 ⁇ 0.4 ° C.
- the dehydrating acid dehydration tower 18 can be operated stably.
- the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ⁇ 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ⁇ . It was 10 ppm.
- the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained.
- the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
- Example 3 Production of acrylonitrile under the same conditions as in Example 1, with the heating amount of the reboiler 24a and the heat removal amount of the condenser 20 made constant, and the acrylonitrile concentration and hydrogen cyanide concentration in each stage above the feed stage were measured. Among the stages having a hydrogen cyanide concentration higher than that of the hydrogen cyanide, the lowest stage was 50 stages counted from the tower bottom. Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the tower is 300 ppm while keeping the heating amount of the reboiler 24a constant, the temperature of the stage is 51 ° C. there were.
- the stage is the temperature control stage B
- the thermometer installed in the stage is the thermometer 22b
- the target temperature of the stage is 48 ° C. It was adjusted. The above operation was continued for about 6 months when the acrylonitrile production amount was 11.5 ⁇ 0.2 t / h. During this time, the temperature of the temperature control stage was 51 ⁇ 0.4 ° C.
- the dehydrating acid dehydration tower can be operated stably. During this time, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ⁇ 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ⁇ 10 ppm. Met.
- the hydrogen cyanide concentration in the acrylonitrile product was 5 ppm or less, and high-quality acrylonitrile products could be obtained stably. Moreover, the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
- Example 4 Propane, ammonia and air were supplied to the same fluidized bed reactor 1 as in Example 1, and propane ammoxidation reaction was performed as follows.
- the fluidized bed catalyst was a molybdenum-vanadium-based supported catalyst having a particle size of 10 to 100 ⁇ m and an average particle size of 55 ⁇ m, and packed so that the stationary bed height was 2.2 m.
- Air was 64500Nm 3 / h supplied from the air distribution plate, propane 4300Nm 3 / h and ammonia from a raw material gas dispersion tube was 4300Nm 3 / h feed.
- the reaction temperature was controlled with a heat removal tube so as to be 440 ° C.
- the pressure was 0.75 kg / cm 2 G.
- the reaction product gas was introduced into the quenching tower 6 and brought into countercurrent contact with water. Further, unreacted ammonia was neutralized and removed with sulfuric acid.
- the gas taken out from the quenching tower 6 was introduced into the absorption tower 9 from the line 8. Absorbed water was introduced from the top line 14 and brought into countercurrent contact with the gas to absorb acrylonitrile, acetonitrile and hydrogen cyanide in the gas into the water. Unabsorbed gas was taken out from the absorption tower top line 11 and incinerated. The amount of absorbed water was adjusted so that the acrylonitrile concentration in the gas taken out from the top of the absorption tower was 100 volppm. The absorption tower bottom liquid was preheated and supplied to the recovery tower 12.
- Acetonitrile and most of the water were separated in the recovery tower, and acrylonitrile, hydrogen cyanide and water were distilled from the top line 17.
- the distillate vapor was condensed to form an organic layer and an aqueous layer, the aqueous layer was recycled to the supply line 10 of the recovery tower, and the organic layer was supplied to the dehydrating acid dehydration tower 18.
- the mass and temperature of the feed liquid to the dehydrating acid dehydration tower 18 were measured by a flow meter and a thermometer (not shown) installed in the line 17. The measured values were 6219 kg / h and 35.0 ° C., respectively.
- Crude hydrogen cyanide gas was extracted from the top line 19 of the dehydrating acid dehydration tower 18 and sent to the condenser 20, where it was cooled and fractionated.
- the refrigerant 20a used in the condenser 20 was 6 ° C. water.
- the condensed hydrogen cyanide liquid was refluxed to the top of the column, and hydrogen cyanide gas with little impurities that was not condensed was extracted from the line 21 to the outside of the system.
- the liquid in the tower was extracted from the 24th stage of the dehydration acid dehydration tower 18 and cooled by the side cut cooler 23b.
- the refrigerant 23a used for the side cut cooler 23b was 25 ° C. water.
- the heat removal amount Q3 of the side cut cooler was adjusted by the flow rate of the refrigerant 23a so that the liquid temperature of the decanter 23d was 30 ° C.
- the side stream extracted from the tower was separated into two layers of an organic layer and an aqueous layer by a decanter 23d, and the aqueous layer was extracted through a line 23f and recycled to the supply liquid of the recovery tower 12.
- the organic layer was returned to the 23rd stage of the tower by line 23e. 110 ° C. process water extracted from the lower part of the recovery tower 12 was used as a heat source for the reboiler 24a.
- the amount of heat Q1 applied was 250 ⁇ 10 3 kcal / h / t-acrylonitrile, and the mass of acrylonitrile obtained as a product in the product tower 25 was 5.22 t per hour, so 1305 ⁇ 10 3 kcal / h Then, the flow rate of the process water 24b leading to the reboiler 24a was adjusted. Crude acrylonitrile was extracted from the tower bottom line 24 and supplied to the product tower 25. The bottom extract was measured for mass by a flow meter (not shown) installed in the line 24, and the measured value was 5312 kg / h.
- the temperature of the liquid extracted from the bottom of the tower was 86 ° C., which was the same as the liquid temperature at the bottom of the dehydration acid dehydration tower 18.
- the heating amount of the reboiler 24a and the heat removal amount of the condenser 20 were made constant, and the acrylonitrile concentration and the hydrogen cyanide concentration in each stage above the feed stage were measured.
- the lower stage was 51 stages from the tower bottom.
- the temperature of the stage is 48 ° C. there were.
- the stage is the temperature control stage B
- the thermometer installed in the stage is the thermometer 22b
- the target temperature of the stage is 48 ° C.
- the heat removal amount of the condenser is set so that the temperature of the stage is 48 ° C. It was adjusted. The above operation was continued for about 4 months when the acrylonitrile production amount was 5.22 ⁇ 0.17 t / h.
- the temperature of the temperature control stage B was 48 ⁇ 0.4 ° C.
- the dehydrating acid dehydration tower can be operated stably.
- the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ⁇ 10 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ⁇ 10 ppm. It was the following.
- the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained.
- the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
- Example 5 Production of acrylonitrile under the same conditions as in Example 4, with the heating amount of the reboiler 24a and the heat removal amount of the condenser 20 made constant, and the acrylonitrile concentration and hydrogen cyanide concentration in each stage above the feed stage were measured. Among the stages having a hydrogen cyanide concentration higher than that of the hydrogen cyanide, the lowest stage was 50 stages counted from the tower bottom. Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the tower is 300 ppm while keeping the heating amount of the reboiler 24a constant, the temperature of the stage is 51 ° C. there were.
- the stage is the temperature control stage B
- the thermometer installed in the stage is the thermometer 22b
- the target temperature of the stage is 48 ° C.
- the heat removal amount of the condenser is set so that the temperature of the stage becomes 51 ° C. It was adjusted. The above operation was continued for about 4 months when the acrylonitrile production amount was 5.22 ⁇ 0.17 t / h. During this time, the temperature of the temperature control stage B was 51 ⁇ 0.4 ° C.
- the dehydrating acid dehydration tower can be operated stably.
- the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ⁇ 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ⁇ 10 ppm. Met.
- the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained.
- the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
- Example 1 The ammoxidation reaction of propylene was carried out using the same equipment and method as in Example 1 except that the uppermost stage of the dehydration acid dehydration tower was a temperature control stage and the temperature of the stage was 30 ° C. Inter-acrylonitrile was produced. During this time, the temperature in the temperature control stage was not changed at 30 ° C., but one month after the start of production, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower increased to 1000 ppm.
- Example 2 The propane ammoxidation reaction was carried out using the same equipment and method as in Example 4 except that the uppermost stage of the dehydration acid dehydration tower was a temperature control stage and the temperature of the stage was 30 ° C. Inter-acrylonitrile was produced. During this time, the temperature in the temperature control stage was not changed at 30 ° C., but two weeks after the start of production, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower increased to 1000 ppm.
- the method of the present invention has industrial applicability in a process for producing acrylonitrile in which propylene and / or propane, ammonia and oxygen are reacted in the presence of a catalyst.
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Abstract
Description
特許文献1には、アクリロニトリルの精製において、脱青酸脱水塔に酸及びハイドロキノンを添加して、アクリロニトリル及びシアン化水素の重合を抑制する方法が開示されている。 In the process of producing acrylonitrile by reacting propylene and / or propane, ammonia and oxygen in the presence of a catalyst, first, the reaction product gas containing acrylonitrile, acetonitrile and hydrogen cyanide is cooled in a quenching tower and unreacted. The ammonia is neutralized and removed with sulfuric acid. Thereafter, the reaction product gas is sent to an absorption tower to absorb acrylonitrile, acetonitrile and hydrogen cyanide in water. Next, an aqueous solution containing acrylonitrile and the like obtained in the absorption tower is introduced into the recovery tower, and from this aqueous solution, a fraction containing acetonitrile and most of water by distillation operation, and a fraction containing most of acrylonitrile and hydrogen cyanide, To separate. After that, a fraction containing most of acrylonitrile and hydrogen cyanide is introduced into a dehydrating acid dehydration tower, hydrogen cyanide and water are separated, and then the bottom liquid is introduced into the product tower, and acrylonitrile is purified by distillation operation. Get a product that fits.
従来、製品であるアクリロニトリルの収量を増加させることについては、当然ながら多くの関心が寄せられ、検討されてきた。一方、収量の増加という直接的な効果を目的とした改良の他にも、製品品質の安定化という間接的な改善によっても技術上及び経済上大きなメリットがあるが、これまで詳細な検討がなされていないのが現状である。
上記事情に鑑み、本発明が解決しようとする課題は、アクリロニトリルの製造プロセスにおいて、製品品質を安定化させる方法を提供することである。 In the dehydrating acid dehydration tower, a solution containing acrylonitrile, hydrogen cyanide and water is distilled, a vapor containing hydrogen cyanide is distilled from the top of the tower, and a solution containing acrylonitrile is withdrawn from the bottom of the tower. The gas containing hydrogen cyanide distilled from the top of the column is cooled and fractionated by a condenser, and the hydrogen cyanide with less impurities that has not been condensed is used as a raw material for the hydrogen cyanide derivative. It is preferred to keep the acrylonitrile concentration low. For this reason, even if the operation for maintaining the top temperature at the target temperature is performed according to a general distillation method, the acrylonitrile concentration in the hydrogen cyanide gas distilled from the top is not stable, and the acrylonitrile concentration in the hydrogen cyanide gas is regulated. The phenomenon of rising above the value is often seen. When this phenomenon occurs, not only does the quality of the hydrogen cyanide derivative raw material become stable, but also the quality of the acrylonitrile product becomes unstable, and further, it becomes a factor in the polymerization of acrylonitrile and hydrogen cyanide in the dehydride dehydration tower.
In the past, increasing the yield of the product acrylonitrile has, of course, received much interest and consideration. On the other hand, in addition to improvements aimed at the direct effect of increasing yield, indirect improvements such as stabilization of product quality also have significant technical and economic benefits, but detailed studies have been made so far. The current situation is not.
In view of the above circumstances, the problem to be solved by the present invention is to provide a method for stabilizing product quality in an acrylonitrile manufacturing process.
[1]
蒸留塔と、前記蒸留塔に接続された、塔頂ガスの凝縮器と、を有する蒸留装置を用いてアクリロニトリル、シアン化水素及び水を含む溶液を蒸留する工程を含むアクリロニトリルの精製方法であって、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段の温度を一定に維持する工程を含む方法。
[2]
前記凝縮器へ冷媒を供給する管及び/又は前記凝縮器から冷媒を排出する管に調整弁が設けられ、前記温度制御段に温度計が設けられており、
前記温度制御段の目標温度を設定し、
前記温度制御段の温度が前記目標温度より高い場合は前記調整弁の開度を調整して冷媒の供給量を増加させ、
前記温度制御段の温度が前記目標温度より低い場合は前記調整弁の開度を調整して冷媒の供給量を減少させることにより前記温度制御段の温度を一定に維持する、上記[1]記載の方法。
[3]
前記温度制御段の温度の上限値及び下限値を設定し、前記温度制御段の温度が前記下限値以上、前記上限値以下で推移するように、前記冷媒の供給量を前記調整弁によって調整する、上記[2]記載の方法。
[4]
前記蒸留塔にリボイラーから一定の熱量を与えながら前記凝縮器の除熱量を増減し、
各除熱量において、前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する各段の温度と、
前記各段におけるアクリロニトリル濃度及びシアン化水素濃度を測定し、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する段であって、前記アクリロニトリル濃度が前記シアン化水素濃度より低い段のうち、最も下部の段(最下段)を、温度制御段に設定し、
前記各除熱量における各段の温度から、前記蒸留塔の塔頂から留出するアクリロニトリルの濃度が最小になるように、前記温度制御段の目標温度を決定する工程を含む、上記[1]~[3]のいずれか記載のアクリロニトリルの精製方法。
[5]
前記蒸留塔にリボイラーから一定の熱量を与えながら前記凝縮器の除熱量を増減し、
各除熱量において、前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する各段の温度と、
前記各段におけるアクリロニトリル濃度及びシアン化水素濃度を測定し、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する段であって、前記アクリロニトリル濃度が前記シアン化水素濃度より高い段のうち、最も上部の段(最上段)を、温度制御段に設定し、
前記各除熱量における各段の温度から、前記蒸留塔の塔頂から留出するアクリロニトリルの濃度が最小になるように、前記温度制御段の目標温度を決定する工程を含む、上記[1]~[3]のいずれか記載のアクリロニトリルの精製方法。
[6]
蒸留塔と、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段に設けられた温度計と、
前記蒸留塔に連結された凝縮器と、
前記凝縮器に連結された冷媒を供給する管及び冷媒を排出する管と、
前記冷媒を供給する管及び/又は冷媒を排出する管に取り付けられた冷媒の供給量を調整するための調整弁と、を有する蒸留装置であって、
前記温度計は温度調節計を介して前記調整弁に接続されており、
前記温度計によって前記温度制御段の温度が前記温度調節計に送信され、
前記温度調節計によって前記温度制御段の温度が目標温度より高い場合には前記調整弁の開度が調整されることにより冷媒の供給量が増やされ、
前記温度制御段の温度が目標温度より低い場合には前記調整弁の開度が調整されることにより冷媒の供給量が減らされる、蒸留装置。 That is, the present invention is as follows.
[1]
A method for purifying acrylonitrile, comprising a step of distilling a solution containing acrylonitrile, hydrogen cyanide and water using a distillation apparatus having a distillation column and a condenser for the top gas connected to the distillation column,
A method comprising a step of maintaining a constant temperature of a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column.
[2]
A regulating valve is provided in a pipe for supplying the refrigerant to the condenser and / or a pipe for discharging the refrigerant from the condenser, and a thermometer is provided in the temperature control stage,
Set the target temperature of the temperature control stage,
When the temperature of the temperature control stage is higher than the target temperature, the opening of the adjustment valve is adjusted to increase the supply amount of the refrigerant,
[1] The above [1], wherein when the temperature of the temperature control stage is lower than the target temperature, the temperature of the temperature control stage is kept constant by adjusting the opening of the regulating valve to reduce the supply amount of the refrigerant. the method of.
[3]
An upper limit value and a lower limit value of the temperature of the temperature control stage are set, and the supply amount of the refrigerant is adjusted by the adjustment valve so that the temperature of the temperature control stage changes between the lower limit value and the upper limit value. The method according to [2] above.
[4]
While giving a certain amount of heat from the reboiler to the distillation column, the heat removal amount of the condenser is increased or decreased,
In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column;
Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage,
A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is lower than the hydrogen cyanide concentration, the lowest stage (bottom stage) is temperature controlled. Set to
The step of determining the target temperature of the temperature control stage from the temperature of each stage in each heat removal amount so that the concentration of acrylonitrile distilled from the top of the distillation column is minimized. The method for purifying acrylonitrile according to any one of [3].
[5]
While giving a certain amount of heat from the reboiler to the distillation column, the heat removal amount of the condenser is increased or decreased,
In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column;
Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage,
A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is higher than the hydrogen cyanide concentration, and the uppermost stage (top stage) is temperature controlled. Set to
The step of determining the target temperature of the temperature control stage from the temperature of each stage in each heat removal amount so that the concentration of acrylonitrile distilled from the top of the distillation column is minimized. The method for purifying acrylonitrile according to any one of [3].
[6]
A distillation tower,
A thermometer provided in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column;
A condenser connected to the distillation column;
A pipe for supplying a refrigerant and a pipe for discharging the refrigerant connected to the condenser;
A distillation apparatus comprising: a pipe for supplying the refrigerant and / or an adjustment valve for adjusting a supply amount of the refrigerant attached to the pipe for discharging the refrigerant,
The thermometer is connected to the regulating valve via a temperature controller,
The temperature of the temperature control stage is transmitted to the temperature controller by the thermometer,
When the temperature of the temperature control stage is higher than the target temperature by the temperature controller, the supply amount of the refrigerant is increased by adjusting the opening of the adjustment valve,
A distillation apparatus in which when the temperature of the temperature control stage is lower than a target temperature, the amount of refrigerant supplied is reduced by adjusting the opening of the regulating valve.
以下、必要に応じて図面を参照しつつ、本実施形態について詳細に説明する。なお、図面中、同一要素には同一符号を付すこととし、重複する説明は省略する。また、上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。装置や部材の寸法比率は図示の比率に限られるものではない。 Hereinafter, modes for carrying out the present invention (hereinafter referred to as the present embodiment) will be described in detail. In addition, this invention is not limited to this embodiment, It can implement in various deformation | transformation within the range of the summary.
Hereinafter, this embodiment will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. The dimensional ratios of the devices and members are not limited to the illustrated ratios.
蒸留塔と、前記蒸留塔に接続された、塔頂ガスの凝縮器と、を有する蒸留装置を用いてアクリロニトリル、シアン化水素及び水を含む溶液を蒸留する工程を含むアクリロニトリルの精製方法であって、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段の温度を一定に維持する工程を含む方法である。 The purification method of acrylonitrile of this embodiment is:
A method for purifying acrylonitrile, comprising a step of distilling a solution containing acrylonitrile, hydrogen cyanide and water using a distillation apparatus having a distillation column and a condenser for the top gas connected to the distillation column,
The method includes a step of maintaining a constant temperature in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column.
急冷塔6上部から取り出されるガスをライン8により吸収塔9に導入する。吸収塔9の塔頂に回収塔12から抜き出した水を吸収水としてライン14から供給し、反応生成ガス中のアクリロニトリル、アセトニトリル及びシアン化水素を水に吸収させる。吸収されなかったプロピレン、プロパン、酸素、窒素、二酸化炭素、一酸化炭素等及び微量の有機物等は、吸収塔の塔頂のライン11より抜き出す。吸収塔9の塔底液はライン10より回収塔12に供給する。
回収塔12の塔頂に抽出水をライン15から導入し、抽出蒸留によりアセトニトリルを抽出分離する。アセトニトリルはライン16よりプロセス系外に抜き出す。また、大部分の水はライン13よりプロセス系外に抜き出す。回収塔の塔頂からライン17によりアクリロニトリル、シアン化水素及び水を留出し、図示していない凝縮器で凝縮した後、図示していないデカンターで有機層と水層の二層に分離する。アクリロニトリル、シアン化水素及び少量の水を含む有機層を脱青酸脱水塔18に供給する。水層は、(ライン10より)回収塔供給液又は(ライン15より)抽出水等として、前工程にリサイクルする。 In the acrylonitrile production process, first, gaseous propylene and / or propane from
A gas taken out from the upper part of the quenching
Extracted water is introduced from the
温度制御段の温度の上限値及び下限値を設定する場合には、温度制御段の温度が下限値以上、上限値以下で推移するように、冷媒の供給量を調整弁によって調整することができる。 The
When setting the upper limit value and the lower limit value of the temperature of the temperature control stage, the supply amount of the refrigerant can be adjusted by the adjusting valve so that the temperature of the temperature control stage changes between the lower limit value and the upper limit value. .
まず、リボイラーの加熱量と凝縮器の除熱量を一定にして、キー物質の濃度(質量%)を各段において調べる(濃度プロファイル)。併せて、各段の温度も測定しておく(温度プロファイル)。次いで、リボイラーの加熱量は変更しないで、凝縮器の除熱量のみを変更し、濃度プロファイル及び温度プロファイルを測定する。凝縮器の除熱量が異なる場合のそれぞれの塔内の温度プロファイルを比較した時、仮に、フィード段の温度同士及び最上段の温度同士がそれぞれの場合で同一であっても、フィード段より上部かつ最上段より下部に位置する各段の温度が異なる場合があり、このとき、各ケースの塔頂及び塔底のキー物質濃度には相違が生じる。つまり、フィード段及び/又は最上段の温度のみを監視していても、塔頂及び塔底のキー物質の濃度を制御することはできない。本発明者は、フィード段より上部かつ最上段より下部に位置する段の温度変化が、キー物質濃度に影響することを発見した。
そして、濃度プロファイルにおいて塔頂及び塔底のキー物質の濃度が逆転する段、具体的には、アクリロニトリル濃度がシアン化水素濃度より低い段のうち、最も下部の段(最下段)の温度、及び/又はアクリロニトリル濃度がシアン化水素濃度より高い段のうち、最も上部の段(最上段)は、塔頂及び/又は塔底のキー物質濃度に強い相関を示すことを見出した。
アクリロニトリルは塔底において高濃度であり、シアン化水素は塔頂において高濃度であるため、両者の濃度はある段で逆転することになるが、この逆転する段はフィード段より上部であって、最上段より下部に位置しており、この段の温度が塔頂及び/又は塔底におけるキー物質の濃度に影響する。従って、濃度プロファイルを参照して、キー物質濃度が逆転する段を、温度制御段の位置として決定することが好ましい。そして、好ましい温度プロファイルにおけるその温度制御段の温度から、目標温度を設定することができる。一般的には好ましい温度プロファイルにおいて、温度制御段の温度は急激な変化を示し、温度プロファイルの変曲点が温度制御段に該当する場合が多い。 Hereinafter, an example of a method for determining the position of the temperature control stage and the target temperature will be described.
First, the reboiler heating amount and the condenser heat removal amount are made constant, and the concentration (mass%) of the key substance is examined in each stage (concentration profile). In addition, the temperature of each stage is also measured (temperature profile). Next, without changing the heating amount of the reboiler, only the heat removal amount of the condenser is changed, and the concentration profile and the temperature profile are measured. When comparing the temperature profiles in each column when the heat removal amount of the condenser is different, even if the temperatures of the feed stages and the temperatures of the uppermost stages are the same in each case, The temperature of each stage located below the uppermost stage may be different, and at this time, a difference occurs in the key substance concentration at the top and bottom of each case. That is, even if only the temperature of the feed stage and / or the uppermost stage is monitored, the concentration of the key substance at the top and the bottom of the tower cannot be controlled. The present inventor has discovered that the temperature change in the stage located above the feed stage and below the top stage affects the key substance concentration.
In the concentration profile, the temperature at the top and the bottom of the column is reversed, specifically, the temperature of the lowest level (the lowest level) among the levels where the acrylonitrile concentration is lower than the hydrogen cyanide concentration, and / or Of the stages where the acrylonitrile concentration is higher than the hydrogen cyanide concentration, the uppermost stage (the uppermost stage) was found to show a strong correlation with the concentration of the key substance at the top and / or bottom of the tower.
Since acrylonitrile is highly concentrated at the bottom of the column and hydrogen cyanide is highly concentrated at the top of the column, the concentration of both is reversed at a certain stage. The temperature of this stage affects the concentration of the key substance at the top and / or bottom of the tower. Therefore, it is preferable to refer to the concentration profile and determine the stage where the key substance concentration is reversed as the position of the temperature control stage. The target temperature can be set from the temperature of the temperature control stage in the preferred temperature profile. In general, in a preferable temperature profile, the temperature of the temperature control stage shows a rapid change, and the inflection point of the temperature profile often corresponds to the temperature control stage.
前記蒸留塔にリボイラーから一定の熱量を与えながら前記凝縮器の除熱量を増減し、
各除熱量において、前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する各段の温度と、
前記各段におけるアクリロニトリル濃度及びシアン化水素濃度を測定し、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する段であって、前記アクリロニトリル濃度が前記シアン化水素濃度より低い段のうち、最も下部の段(最下段)及び/又は前記アクリロニトリル濃度が前記シアン化水素濃度より高い段のうち、最も上部の段(最上段)を、温度制御段に設定し、
前記各除熱量における各段の温度から、前記蒸留塔の塔頂から留出するアクリロニトリルの濃度が最小になるように、前記温度制御段の目標温度を決定する工程を含む。 That is, as a preferable aspect in the method of the present embodiment,
While giving a certain amount of heat from the reboiler to the distillation column, the heat removal amount of the condenser is increased or decreased,
In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column;
Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage,
A stage located above the feed stage of the distillation column and below the top stage of the distillation column, wherein the acrylonitrile concentration is lower than the hydrogen cyanide concentration, the lowest stage (bottom stage) and / or the stage Among the stages where the acrylonitrile concentration is higher than the hydrogen cyanide concentration, the uppermost stage (the uppermost stage) is set as the temperature control stage,
Determining the target temperature of the temperature control stage so that the concentration of acrylonitrile distilled from the top of the distillation column is minimized from the temperature of each stage in each heat removal amount.
蒸留塔と、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段に設けられた温度計と、
前記蒸留塔に連結された凝縮器と、
前記凝縮器に連結された冷媒を供給する管及び冷媒を排出する管と、
前記冷媒を供給する管及び/又は冷媒を排出する管に取り付けられた冷媒の供給量を調整するための調整弁と、を有する蒸留装置であって、
前記温度計は温度調節計を介して前記調整弁に接続されており、
前記温度計によって前記温度制御段の温度が前記温度調節計に送信され、
前記温度調節計によって前記温度制御段の温度が目標温度を超えた場合には前記調整弁の開度が調整されることにより冷媒の供給量が増やされ、前記温度制御段の温度が目標温度未満の場合には前記調整弁の開度が調整されることにより冷媒の供給量が減らされる、蒸留装置。 Although it does not specifically limit as an apparatus for performing the purification method of this embodiment, For example, it can carry out using the following distillation apparatuses.
A distillation tower,
A thermometer provided in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column;
A condenser connected to the distillation column;
A pipe for supplying a refrigerant and a pipe for discharging the refrigerant connected to the condenser;
A distillation apparatus comprising: a pipe for supplying the refrigerant and / or an adjustment valve for adjusting a supply amount of the refrigerant attached to the pipe for discharging the refrigerant,
The thermometer is connected to the regulating valve via a temperature controller,
The temperature of the temperature control stage is transmitted to the temperature controller by the thermometer,
When the temperature of the temperature control stage exceeds the target temperature by the temperature controller, the supply amount of the refrigerant is increased by adjusting the opening of the adjustment valve, and the temperature of the temperature control stage is less than the target temperature. In this case, the amount of refrigerant supplied is reduced by adjusting the opening of the adjusting valve.
アクリロニトリルの分析は、以下の装置及び条件でガスクロマトグラフィーにより行った。
ガスクロマトグラフィーは、装置として島津GC-17Aを用い、カラムはTC-FFAP 60m×0.32膜厚0.25μmを用いた。検出器はFID、キャリヤーガスにはヘリウムを用いた。
カラム温度条件は、以下の通りであった。
初期温度:50℃
昇温速度:5℃/分
最終温度1:180℃ 15分HOLD
昇温速度:10℃/分
最終温度2:230℃ 10分HOLD
最終温度3:50℃ 5分HOLD Hereinafter, the present embodiment will be described in more detail with reference to examples. However, the present embodiment is not limited to the examples described below. In addition, the acrylonitrile manufacturing process in an Example is the same as that of what was shown in FIG. Further, the dehydrating acid dehydration tower in the examples is the same as that shown in FIG.
Analysis of acrylonitrile was performed by gas chromatography using the following apparatus and conditions.
In the gas chromatography, Shimadzu GC-17A was used as an apparatus, and TC-FFAP 60 m × 0.32 film thickness 0.25 μm was used as a column. The detector used was FID and the carrier gas used helium.
The column temperature conditions were as follows.
Initial temperature: 50 ° C
Temperature rising rate: 5 ° C / min Final temperature 1: 180 °
Temperature increase rate: 10 ° C / min Final temperature 2: 230 °
Final temperature 3: 50 ° C, 5 minutes HOLD
流量計:YKOGAWA製 差圧式流量計(オリフィス型) Differential Pressure Transmitter DP hard EJX
温度計:OKAZAKI製 抵抗温度計 Resistance Thermometer, Temperature Trans The following were used as a flow meter and a thermometer.
Flow meter: YKOGAWA differential pressure flow meter (orifice type) Differential Pressure Transmitter DP hard EJX
Thermometer: Resistance Thermometer, Temperature Trans made by OKAZAKI
プロピレン、アンモニア及び空気を内径8m、長さ20mの縦型円筒型の流動層反応器1に供給し、プロピレンのアンモ酸化反応を下記の通り行った。流動層反応器1は、その内部に原料ガス分散管や分散板、除熱管及びサイクロンを有していた。脱青酸脱水塔18は、シーブトレイ55段からなり、塔底から数えて37段目にフィード段A、24段目にチムニートレイDを有し、24段にサイドカット流を抜き出すライン23を有し、サイドカットクーラー23b、デカンター23dを経て、23段目にデカンター内の有機層を戻すライン23eを有していた。
流動層触媒は、粒径10~100μm、平均粒径55μmであるモリブデン-ビスマス-鉄系担持触媒を用い、静止層高2.7mとなるよう充填した。空気分散板から空気を56000Nm3/h供給し、原料ガス分散管からプロピレン6200Nm3/h及びアンモニアを6600Nm3/h供給した。反応温度は440℃となるよう除熱管で制御した。圧力は0.70kg/cm2Gであった。
反応生成ガスを急冷塔6に導入し、水と向流接触させ、未反応のアンモニアを硫酸で中和除去した。急冷塔6から流出したガスをライン8より吸収塔9に導入した。吸収塔9塔頂のライン14より吸収水を導入し、ガスと向流接触させ、ガス中のアクリロニトリル、アセトニトリル及びシアン化水素を水中に吸収させた。吸収水量は、吸収塔塔頂から排出されるガス中のアクリロニトリル濃度が100volppmとなるように調整した。吸収されなかったガスは、吸収塔塔頂ライン11より取り出し、焼却した。
吸収塔塔底液を80℃に予熱し、回収塔12に供給した。回収塔12でアセトニトリル及び大部分の水を分離し、塔頂ライン17からアクリロニトリル、シアン化水素及び水を留出させた。該留出蒸気を凝縮し、図示していない回収塔デカンターで有機層と水層を形成させ、水層は回収塔12の供給ライン10にリサイクルし、有機層は脱青酸脱水塔18に供給した。
脱青酸脱水塔18へのフィード液は、ライン17に設置された図示していない流量計及び温度計により、質量及び温度を測定した。測定値は、それぞれ13595kg/h及び35.0℃であった。
脱青酸脱水塔18の塔頂ライン19から粗シアン化水素ガスを抜き出して凝縮器20に送り、冷却して分縮した。凝縮器20に用いた冷媒20aは、6℃の水であった。凝縮したシアン化水素液を塔頂に還流し、凝縮しなかった不純物の少ないシアン化水素ガスをライン21から系外に抜き出した。
脱青酸脱水塔18の24段から塔内液を抜き出し、サイドカットクーラー23bで冷却した。サイドカットクーラー23bに用いた冷媒23aは、25℃の水であった。サイドカットクーラーの除熱量Q3は、デカンター23dの液温が30℃となるように、冷媒23aの流量で調整した。塔から抜き出したサイド流は、デカンター23dにて有機層と水層の二層に分離し、水層は、ライン23fにより抜き出し、回収塔12の供給液にリサイクルした。有機層はライン23eにより、塔の23段に戻した。
リボイラー24aの熱源には、回収塔12下部から抜き出した110℃のプロセス水を用いた。与えた熱量Q1は200×103kcal/h/t-アクリロニトリルとし、製品塔25にて製品として取得したアクリロニトリルの質量が、時間当たり11.5tであったので、2300×103kcal/hとなるよう、リボイラー24aに通じるプロセス水24bの流量を調整した。
塔底ライン24から粗アクリロニトリルを抜き出し、製品塔25に送った。塔底抜出液は、ライン24に設置された図示していない流量計により質量を測定し、その測定値は、11585kg/hであった。塔底抜出液の温度は、脱青酸脱水塔18の塔底の液温と同一であり86℃であった。
ここで、リボイラー24aの加熱量と凝縮器20の除熱量を一定にして、フィード段より上部の各段におけるアクリロニトリル濃度とシアン化水素濃度を測定した結果、アクリロニトリル濃度がシアン化水素濃度より低い段のうち、最も下部の段は塔底から数えて51段であった。
次に、リボイラー24aの加熱量を一定としたままで、塔頂から留出するシアン化水素中のアクリロニトリル濃度を300ppmとなるように凝縮器の除熱量を調整した結果、当該段の温度は48℃であった。
ここで当該段を温度制御段B、当該段に設置された温度計を温度計22b、当該段の目標温度を48℃として、当該段の温度が48℃となるように凝縮器の除熱量を調整した。
アクリロニトリル生産量を11.5±0.2t/hとした時期約6ヶ月間、上記運転を継続した。この間、温度制御段の温度は、48±0.4℃であった。
脱青酸脱水塔は安定的に運転でき、この間、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度は300±20ppmであり、塔底から抜き出されるアクリロニトリル中のシアン化水素濃度は40±10ppmであった。またこの間、アクリロニトリル製品中のシアン化水素濃度は5ppm以下であり、高品質のアクリロニトリル製品を安定的に取得できた。また、粗シアン化水素の純度も安定しており、シアン化水素誘導体の品質にも問題はなかった。 [Example 1]
Propylene, ammonia and air were supplied to a vertical cylindrical
As the fluidized bed catalyst, a molybdenum-bismuth-iron-based supported catalyst having a particle size of 10 to 100 μm and an average particle size of 55 μm was used and packed so as to have a stationary bed height of 2.7 m. Air was 56000Nm 3 / h supplied from the air distribution plate, propylene 6200Nm 3 / h and ammonia from a raw material gas dispersion tube was 6600Nm 3 / h feed. The reaction temperature was controlled with a heat removal tube so as to be 440 ° C. The pressure was 0.70 kg / cm 2 G.
The reaction product gas was introduced into the quenching
The absorption tower bottom liquid was preheated to 80 ° C. and supplied to the
The mass and temperature of the feed liquid to the dehydrating
Crude hydrogen cyanide gas was extracted from the
The liquid in the tower was extracted from the 24th stage of the dehydration
110 ° C. process water extracted from the lower part of the
Crude acrylonitrile was extracted from the
Here, the heating amount of the
Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the column is 300 ppm while the heating amount of the
Here, the stage is the temperature control stage B, the thermometer installed in the stage is the
The above operation was continued for about 6 months when the acrylonitrile production amount was 11.5 ± 0.2 t / h. During this time, the temperature of the temperature control stage was 48 ± 0.4 ° C.
The dehydrating acid dehydration tower can be operated stably. During this time, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ± 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ± 10 ppm. Met. During this time, the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained. Moreover, the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
生産計画の変更によりアクリロニトリル生産量を12.7t/hに増量したこと以外は、実施例1と同一の設備及び方法でアクリロニトリルを製造した。
リボイラー熱量は2540×103kcal/hまで増加させた。脱青酸脱水塔18の温度制御段Bの温度が48℃となるよう温度調節計22aを介して、冷媒20aの流量調節弁20bを制御した。脱青酸脱水塔18の塔内の各温度及びデカンター23dの温度は、実施例1とほぼ同一であった。
アクリロニトリル生産量を12.7±0.2t/hとした時期約3ヶ月間、上記運転を継続した。この間、温度制御段の温度は、48±0.4℃であった。脱青酸脱水塔18は安定的に運転でき、この間、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度は300±20ppmであり、塔底から抜き出されるアクリロニトリル中のシアン化水素濃度は40±10ppmであった。またこの間、アクリロニトリル製品中のシアン化水素濃度は5ppm以下であり、高品質のアクリロニトリル製品を安定的に取得できた。また、粗シアン化水素の純度も安定しており、シアン化水素誘導体の品質にも問題はなかった。 [Example 2]
Acrylonitrile was produced using the same equipment and method as in Example 1 except that the production amount of acrylonitrile was increased to 12.7 t / h by changing the production plan.
The reboiler heat was increased to 2540 × 10 3 kcal / h. The flow
The above operation was continued for about 3 months when the acrylonitrile production amount was 12.7 ± 0.2 t / h. During this time, the temperature of the temperature control stage was 48 ± 0.4 ° C. The dehydrating
実施例1と同じ条件でアクリロニトリルの製造を行い、リボイラー24aの加熱量と凝縮器20の除熱量を一定にして、フィード段より上部の各段におけるアクリロニトリル濃度とシアン化水素濃度を測定した結果、アクリロニトリル濃度がシアン化水素濃度より高い段のうち、最も下部の段は塔底から数えて50段であった。
次に、リボイラー24aの加熱量を一定としたままで、塔頂から留出するシアン化水素中のアクリロニトリル濃度を300ppmとなるように凝縮器の除熱量を調整した結果、当該段の温度は51℃であった。
ここで当該段を温度制御段B、当該段に設置された温度計を温度計22b、当該段の目標温度を48℃として、当該段の温度が51℃となるように凝縮器の除熱量を調整した。
アクリロニトリル生産量を11.5±0.2t/hとした時期約6ヶ月間、上記運転を継続した。この間、温度制御段の温度は、51±0.4℃であった。脱青酸脱水塔は安定的に運転でき、この間、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度は300±20ppmであり、塔底から抜き出されるアクリロニトリル中のシアン化水素濃度は40±10ppmであった。またこの間、アクリロニトリル製品中のシアン化水素濃度は5ppm以下であり、高品質のアクリルニトリル製品を安定的に取得できた。また、粗シアン化水素の純度も安定しており、シアン化水素誘導体の品質にも問題はなかった。 [Example 3]
Production of acrylonitrile under the same conditions as in Example 1, with the heating amount of the
Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the tower is 300 ppm while keeping the heating amount of the
Here, assuming that the stage is the temperature control stage B, the thermometer installed in the stage is the
The above operation was continued for about 6 months when the acrylonitrile production amount was 11.5 ± 0.2 t / h. During this time, the temperature of the temperature control stage was 51 ± 0.4 ° C. The dehydrating acid dehydration tower can be operated stably. During this time, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ± 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ± 10 ppm. Met. During this period, the hydrogen cyanide concentration in the acrylonitrile product was 5 ppm or less, and high-quality acrylonitrile products could be obtained stably. Moreover, the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
プロパン、アンモニア及び空気を実施例1と同じ流動層反応器1に供給し、プロパンのアンモ酸化反応を下記の通り行った。
流動層触媒は、粒径10~100μm、平均粒径55μmであるモリブデン-バナジウム系担持触媒を用い、静止層高2.2mとなるよう充填した。空気分散板から空気を64500Nm3/h供給し、原料ガス分散管からプロパン4300Nm3/h及びアンモニアを4300Nm3/h供給した。反応温度は440℃となるよう除熱管で制御した。圧力は0.75kg/cm2Gであった。
反応生成ガスを急冷塔6に導入し、水と向流接触させた。また、未反応のアンモニアを硫酸で中和除去した。
急冷塔6から取り出したガスをライン8より吸収塔9に導入した。塔頂ライン14より吸収水を導入し、ガスと向流接触させ、ガス中のアクリロニトリル、アセトニトリル及びシアン化水素を水中に吸収させた。未吸収のガスは、吸収塔塔頂ライン11より取り出し、焼却した。吸収塔塔頂から取り出したガス中のアクリロニトリル濃度が100volppmとなるよう、吸収水量を調整した。
吸収塔塔底液を予熱し、回収塔12に供給した。回収塔でアセトニトリル及び大部分の水を分離し、塔頂ライン17からアクリロニトリル、シアン化水素及び水を留出させた。該留出蒸気を凝縮し、有機層と水層を形成させ、水層は回収塔の供給ライン10にリサイクルし、有機層は脱青酸脱水塔18に供給した。
脱青酸脱水塔18へのフィード液は、ライン17に設置された図示していない流量計及び温度計により、質量及び温度を測定した。測定値は、それぞれ6219kg/h及び35.0℃であった。
脱青酸脱水塔18の塔頂ライン19から粗シアン化水素ガスを抜き出して凝縮器20に送り、冷却して分縮した。凝縮器20に用いた冷媒20aは、6℃の水であった。凝縮したシアン化水素液を塔頂に還流し、凝縮しなかった不純物の少ないシアン化水素ガスをライン21から系外に抜き出した。
脱青酸脱水塔18の24段から塔内液を抜き出し、サイドカットクーラー23bで冷却した。サイドカットクーラー23bに用いた冷媒23aは、25℃の水であった。サイドカットクーラーの除熱量Q3は、デカンター23dの液温が30℃となるように、冷媒23aの流量で調整した。塔から抜き出したサイド流は、デカンター23dにて有機層と水層の二層に分離し、水層は、ライン23fにより抜き出し、回収塔12の供給液にリサイクルした。有機層はライン23eにより、塔の23段に戻した。
リボイラー24aの熱源には、回収塔12下部から抜き出した110℃のプロセス水を用いた。与えた熱量Q1は、250×103kcal/h/t-アクリロニトリルとし、製品塔25にて製品として取得したアクリロニトリルの質量が、時間当たり5.22tであったので、1305×103kcal/hとなるよう、リボイラー24aに通じるプロセス水24bの流量を調整した。
塔底ライン24から粗アクリロニトリルを抜き出し、製品塔25に供給した。塔底抜出液は、ライン24に設置された図示していない流量計により、質量を測定し、その測定値は5312kg/hであった。塔底抜出液の温度は、脱青酸脱水塔18の塔底の液温と同一であり86℃であった。
ここで、リボイラー24aの加熱量と凝縮器20の除熱量を一定にして、フィード段より上部の各段におけるアクリロニトリル濃度とシアン化水素濃度を測定した結果、アクリロニトリル濃度がシアン化水素濃度より低い段のうち、最も下部の段は塔底から数えて51段であった。
次に、リボイラー24aの加熱量を一定としたままで、塔頂から留出するシアン化水素中のアクリロニトリル濃度を300ppmとなるように凝縮器の除熱量を調整した結果、当該段の温度は48℃であった。
ここで当該段を温度制御段B、当該段に設置された温度計を温度計22b、当該段の目標温度を48℃として、当該段の温度が48℃となるように凝縮器の除熱量を調整した。
アクリロニトリル生産量を5.22±0.17t/hとした時期約4ヶ月間、上記運転を継続した。この間、温度制御段Bの温度は、48±0.4℃であった。脱青酸脱水塔は安定的に運転でき、この間、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度は300±10ppmであり、塔底から抜き出されるアクリロニトリル中のシアン化水素濃度は40±10ppm以下であった。またこの間、アクリロニトリル製品中のシアン化水素濃度は5ppm以下であり、高品質のアクリロニトリル製品を安定的に取得できた。また、粗シアン化水素の純度も安定しており、シアン化水素誘導体の品質にも問題はなかった。 [Example 4]
Propane, ammonia and air were supplied to the same
The fluidized bed catalyst was a molybdenum-vanadium-based supported catalyst having a particle size of 10 to 100 μm and an average particle size of 55 μm, and packed so that the stationary bed height was 2.2 m. Air was 64500Nm 3 / h supplied from the air distribution plate, propane 4300Nm 3 / h and ammonia from a raw material gas dispersion tube was 4300Nm 3 / h feed. The reaction temperature was controlled with a heat removal tube so as to be 440 ° C. The pressure was 0.75 kg / cm 2 G.
The reaction product gas was introduced into the quenching
The gas taken out from the quenching
The absorption tower bottom liquid was preheated and supplied to the
The mass and temperature of the feed liquid to the dehydrating
Crude hydrogen cyanide gas was extracted from the
The liquid in the tower was extracted from the 24th stage of the dehydration
110 ° C. process water extracted from the lower part of the
Crude acrylonitrile was extracted from the
Here, the heating amount of the
Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the column is 300 ppm while the heating amount of the
Here, the stage is the temperature control stage B, the thermometer installed in the stage is the
The above operation was continued for about 4 months when the acrylonitrile production amount was 5.22 ± 0.17 t / h. During this time, the temperature of the temperature control stage B was 48 ± 0.4 ° C. The dehydrating acid dehydration tower can be operated stably. During this time, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ± 10 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ± 10 ppm. It was the following. During this time, the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained. Moreover, the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
実施例4と同じ条件でアクリロニトリルの製造を行い、リボイラー24aの加熱量と凝縮器20の除熱量を一定にして、フィード段より上部の各段におけるアクリロニトリル濃度とシアン化水素濃度を測定した結果、アクリロニトリル濃度がシアン化水素濃度より高い段のうち、最も下部の段は塔底から数えて50段であった。
次に、リボイラー24aの加熱量を一定としたままで、塔頂から留出するシアン化水素中のアクリロニトリル濃度を300ppmとなるように凝縮器の除熱量を調整した結果、当該段の温度は51℃であった。
ここで当該段を温度制御段B、当該段に設置された温度計を温度計22b、当該段の目標温度を48℃として、当該段の温度が51℃となるように凝縮器の除熱量を調整した。
アクリロニトリル生産量を5.22±0.17t/hとした時期約4ヶ月間、上記運転を継続した。この間、温度制御段Bの温度は、51±0.4℃であった。脱青酸脱水塔は安定的に運転でき、この間、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度は300±20ppmであり、塔底から抜き出されるアクリロニトリル中のシアン化水素濃度は40±10ppmであった。またこの間、アクリロニトリル製品中のシアン化水素濃度は5ppm以下であり、高品質のアクリロニトリル製品を安定的に取得できた。また、粗シアン化水素の純度も安定しており、シアン化水素誘導体の品質にも問題はなかった。 [Example 5]
Production of acrylonitrile under the same conditions as in Example 4, with the heating amount of the
Next, as a result of adjusting the heat removal amount of the condenser so that the acrylonitrile concentration in the hydrogen cyanide distilled from the top of the tower is 300 ppm while keeping the heating amount of the
Here, the stage is the temperature control stage B, the thermometer installed in the stage is the
The above operation was continued for about 4 months when the acrylonitrile production amount was 5.22 ± 0.17 t / h. During this time, the temperature of the temperature control stage B was 51 ± 0.4 ° C. The dehydrating acid dehydration tower can be operated stably. During this time, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower is 300 ± 20 ppm, and the concentration of hydrogen cyanide in acrylonitrile extracted from the bottom of the tower is 40 ± 10 ppm. Met. During this time, the concentration of hydrogen cyanide in the acrylonitrile product was 5 ppm or less, and a high-quality acrylonitrile product was stably obtained. Moreover, the purity of the crude hydrogen cyanide was stable, and there was no problem with the quality of the hydrogen cyanide derivative.
脱青酸脱水塔の最上段を温度制御段とし、当該段の温度が30℃となるよう運転したこと以外は、実施例1と同一の設備及び方法でプロピレンのアンモ酸化反応を実施し、3ヶ月間アクリロニトリルを製造した。この間、温度制御段の温度は30℃で変化がなかったが、製造開始から1ヵ月後に、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度が1000ppmに上昇した。凝縮器の除熱量Q2が不足していると判断し、凝縮器に通じる冷媒の流量を上げてQ2を増加させところ、脱青酸脱水塔の最上段の温度は30℃で変化がなかったが、塔頂から留出するシアン化水素中のアクリロニトリル濃度は300ppmまで減少した。
製造開始から2ヵ月後に製品として取得したアクリロニトリル中のシアン化水素の濃度が20ppmまで上昇しオフスペック品となった。この時、脱青酸脱水塔の塔底液中のシアン化水素濃度は、120wtppmであった。凝縮器の除熱量Q2が過多と判断し、凝縮器に通じる冷媒の流量を下げてQ2を減少させたところ、製品として取得したアクリロニトリル中のシアン化水素濃度が5ppmまで減少しオンスペック品となった。また、塔頂から留出するシアン化水素中に留出するアクリロニトリルの割合は600ppmまで上昇し、シアン化水素誘導体の品質が落ちていた。この間、脱青酸脱水塔の最上段の温度は30℃で変化がなかった。 [Comparative Example 1]
The ammoxidation reaction of propylene was carried out using the same equipment and method as in Example 1 except that the uppermost stage of the dehydration acid dehydration tower was a temperature control stage and the temperature of the stage was 30 ° C. Inter-acrylonitrile was produced. During this time, the temperature in the temperature control stage was not changed at 30 ° C., but one month after the start of production, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower increased to 1000 ppm. It was judged that the heat removal amount Q2 of the condenser was insufficient, and when Q2 was increased by increasing the flow rate of the refrigerant leading to the condenser, the temperature of the uppermost stage of the dehydrating acid dehydration tower was not changed at 30 ° C. The acrylonitrile concentration in the hydrogen cyanide distilled from the top of the column was reduced to 300 ppm.
Two months after the start of production, the concentration of hydrogen cyanide in acrylonitrile obtained as a product increased to 20 ppm and became an off-spec product. At this time, the concentration of hydrogen cyanide in the bottom liquid of the dehydride dehydration tower was 120 wtppm. When it was judged that the amount of heat removal Q2 in the condenser was excessive and Q2 was reduced by reducing the flow rate of the refrigerant leading to the condenser, the hydrogen cyanide concentration in the acrylonitrile obtained as a product was reduced to 5 ppm and became an on-spec product. Moreover, the ratio of acrylonitrile distilled in the hydrogen cyanide distilled from the tower top rose to 600 ppm, and the quality of the hydrogen cyanide derivative was lowered. During this time, the temperature of the uppermost stage of the dehydrating acid dehydration tower was 30 ° C. and did not change.
脱青酸脱水塔の最上段を温度制御段とし、当該段の温度が30℃となるよう運転したこと以外は、実施例4と同一の設備及び方法でプロパンのアンモ酸化反応を実施し、2ヶ月間アクリロニトリルを製造した。この間、温度制御段の温度は30℃で変化がなかったが、製造開始から2週間後に、脱青酸脱水塔塔頂から留出するシアン化水素中のアクリロニトリル濃度が1000ppmに上昇した。凝縮器の除熱量Q2が不足していると判断し、凝縮器に通じる冷媒の流量を上げてQ2を増加させところ、脱青酸脱水塔の最上段の温度は30℃で変化がなかったが、塔頂から留出するシアン化水素中のアクリロニトリル濃度は300ppmまで減少した。
製造開始から4週間後に製品として取得したアクリロニトリル中のシアン化水素の濃度が20ppmまで上昇しオフスペック品となった。この時、脱青酸脱水塔の塔底液中のシアン化水素濃度は、120wtppmであった。凝縮器の除熱量Q2が過多と判断し、凝縮器に通じる冷媒の流量を下げてQ2を減少させたところ、製品として取得したアクリロニトリル中のシアン化水素濃度が5ppmまで減少しオンスペック品となった。また、塔頂から留出するシアン化水素中に留出するアクリロニトリルの割合は600ppmまで上昇し、シアン化水素誘導体の品質が落ちていた。この間、脱青酸脱水塔の最上段の温度は30℃で変化がなかった。 [Comparative Example 2]
The propane ammoxidation reaction was carried out using the same equipment and method as in Example 4 except that the uppermost stage of the dehydration acid dehydration tower was a temperature control stage and the temperature of the stage was 30 ° C. Inter-acrylonitrile was produced. During this time, the temperature in the temperature control stage was not changed at 30 ° C., but two weeks after the start of production, the concentration of acrylonitrile in hydrogen cyanide distilled from the top of the dehydrating acid dehydration tower increased to 1000 ppm. It was judged that the heat removal amount Q2 of the condenser was insufficient, and when Q2 was increased by increasing the flow rate of the refrigerant leading to the condenser, the temperature of the uppermost stage of the dehydrating acid dehydration tower was not changed at 30 ° C. The acrylonitrile concentration in the hydrogen cyanide distilled from the top of the column was reduced to 300 ppm.
Four weeks after the start of production, the concentration of hydrogen cyanide in acrylonitrile obtained as a product increased to 20 ppm and became an off-spec product. At this time, the concentration of hydrogen cyanide in the bottom liquid of the dehydride dehydration tower was 120 wtppm. When it was judged that the amount of heat removal Q2 in the condenser was excessive and Q2 was reduced by reducing the flow rate of the refrigerant leading to the condenser, the hydrogen cyanide concentration in the acrylonitrile obtained as a product was reduced to 5 ppm and became an on-spec product. Moreover, the ratio of acrylonitrile distilled in the hydrogen cyanide distilled from the tower top rose to 600 ppm, and the quality of the hydrogen cyanide derivative was lowered. During this time, the temperature of the uppermost stage of the dehydrating acid dehydration tower was 30 ° C. and did not change.
2 プロピレン及び/又はプロパンの供給管
3 アンモニアの供給管
4 空気(酸素)の供給管
6 急冷塔
5、7、8 ライン
9 吸収塔
10、11 ライン
12 回収塔
13、14、15、16、17 ライン
18 脱青酸脱水塔
19 ライン
20 脱青酸脱水塔凝縮器
20a 脱青酸脱水塔凝縮器に供給する冷媒
20b 脱青酸脱水塔凝縮器に供給する冷媒の流量調節弁
20b’ 凝縮器の冷媒の供給管と排出管とを接続する流量調節弁
21、22 ライン
22a 温度調節計
22b 温度検出器(温度計)
23、23c、23e、23f ライン
23a 脱青酸脱水塔サイドカットクーラーに供給する冷媒
23b 脱青酸脱水塔サイドカットクーラー
23d 脱青酸脱水塔デカンター
24、24c ライン
24a 脱青酸脱水塔リボイラー
24b 脱青酸脱水塔リボイラーに供給する熱媒
25 製品塔
26、27、28、29 ライン
30 製品塔凝縮器
31 ライン
A フィード段
B 温度制御段
C 最上段
D チムニートレイ DESCRIPTION OF
23, 23c, 23e,
Claims (6)
- 蒸留塔と、前記蒸留塔に接続された、塔頂ガスの凝縮器と、を有する蒸留装置を用いてアクリロニトリル、シアン化水素及び水を含む溶液を蒸留する工程を含むアクリロニトリルの精製方法であって、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段の温度を一定に維持する工程を含む方法。 A method for purifying acrylonitrile, comprising a step of distilling a solution containing acrylonitrile, hydrogen cyanide and water using a distillation apparatus having a distillation column and a condenser for the top gas connected to the distillation column,
A method comprising a step of maintaining a constant temperature of a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column. - 前記凝縮器へ冷媒を供給する管及び/又は前記凝縮器から冷媒を排出する管に調整弁が設けられ、前記温度制御段に温度計が設けられており、
前記温度制御段の目標温度を設定し、
前記温度制御段の温度が前記目標温度より高い場合は前記調整弁の開度を調整して冷媒の供給量を増加させ、
前記温度制御段の温度が前記目標温度より低い場合は前記調整弁の開度を調整して冷媒の供給量を減少させることにより前記温度制御段の温度を一定に維持する、請求項1記載の方法。 A regulating valve is provided in a pipe for supplying the refrigerant to the condenser and / or a pipe for discharging the refrigerant from the condenser, and a thermometer is provided in the temperature control stage,
Set the target temperature of the temperature control stage,
When the temperature of the temperature control stage is higher than the target temperature, the opening of the adjustment valve is adjusted to increase the supply amount of the refrigerant,
2. The temperature of the temperature control stage is kept constant by adjusting the opening of the regulating valve to reduce the supply amount of the refrigerant when the temperature of the temperature control stage is lower than the target temperature. Method. - 前記温度制御段の温度の上限値及び下限値を設定し、前記温度制御段の温度が前記下限値以上、前記上限値以下で推移するように、前記冷媒の供給量を前記調整弁によって調整する、請求項2記載の方法。 An upper limit value and a lower limit value of the temperature of the temperature control stage are set, and the supply amount of the refrigerant is adjusted by the adjustment valve so that the temperature of the temperature control stage changes between the lower limit value and the upper limit value. The method according to claim 2.
- 前記蒸留塔にリボイラーから一定の熱量を与えながら前記凝縮器の除熱量を増減し、
各除熱量において、前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する各段の温度と、
前記各段におけるアクリロニトリル濃度及びシアン化水素濃度を測定し、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する段であって、前記アクリロニトリル濃度が前記シアン化水素濃度より低い段のうち、最も下部の段(最下段)を、温度制御段に設定し、
前記各除熱量における各段の温度から、前記蒸留塔の塔頂から留出するアクリロニトリルの濃度が最小になるように、前記温度制御段の目標温度を決定する工程を含む、請求項1~3のいずれか1項記載のアクリロニトリルの精製方法。 While giving a certain amount of heat from the reboiler to the distillation column, the heat removal amount of the condenser is increased or decreased,
In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column;
Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage,
A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is lower than the hydrogen cyanide concentration, the lowest stage (bottom stage) is temperature controlled. Set to
The step of determining a target temperature of the temperature control stage from the temperature of each stage in each heat removal amount so as to minimize the concentration of acrylonitrile distilled from the top of the distillation column. The method for purifying acrylonitrile according to any one of the above. - 前記蒸留塔にリボイラーから一定の熱量を与えながら前記凝縮器の除熱量を増減し、
各除熱量において、前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する各段の温度と、
前記各段におけるアクリロニトリル濃度及びシアン化水素濃度を測定し、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する段であって、前記アクリロニトリル濃度が前記シアン化水素濃度より高い段のうち、最も上部の段(最上段)を、温度制御段に設定し、
前記各除熱量における各段の温度から、前記蒸留塔の塔頂から留出するアクリロニトリルの濃度が最小になるように、前記温度制御段の目標温度を決定する工程を含む、請求項1~3のいずれか1項記載のアクリロニトリルの精製方法。 While giving a certain amount of heat from the reboiler to the distillation column, the heat removal amount of the condenser is increased or decreased,
In each heat removal amount, the temperature of each stage located above the feed stage of the distillation column and below the top stage of the distillation column;
Measure the acrylonitrile concentration and hydrogen cyanide concentration in each stage,
A stage located above the feed stage of the distillation column and below the top stage of the distillation tower, wherein the acrylonitrile concentration is higher than the hydrogen cyanide concentration, and the uppermost stage (top stage) is temperature controlled. Set to
The step of determining a target temperature of the temperature control stage from the temperature of each stage in each heat removal amount so as to minimize the concentration of acrylonitrile distilled from the top of the distillation column. The method for purifying acrylonitrile according to any one of the above. - 蒸留塔と、
前記蒸留塔のフィード段より上部かつ前記蒸留塔の最上段より下部に位置する温度制御段に設けられた温度計と、
前記蒸留塔に連結された凝縮器と、
前記凝縮器に連結された冷媒を供給する管及び冷媒を排出する管と、
前記冷媒を供給する管及び/又は冷媒を排出する管に取り付けられた冷媒の供給量を調整するための調整弁と、を有する蒸留装置であって、
前記温度計は温度調節計を介して前記調整弁に接続されており、
前記温度計によって前記温度制御段の温度が前記温度調節計に送信され、
前記温度調節計によって前記温度制御段の温度が目標温度より高い場合には前記調整弁の開度が調整されることにより冷媒の供給量が増やされ、
前記温度制御段の温度が目標温度より低い場合には前記調整弁の開度が調整されることにより冷媒の供給量が減らされる、蒸留装置。 A distillation tower,
A thermometer provided in a temperature control stage located above the feed stage of the distillation column and below the uppermost stage of the distillation column;
A condenser connected to the distillation column;
A pipe for supplying a refrigerant and a pipe for discharging the refrigerant connected to the condenser;
A distillation apparatus comprising: a pipe for supplying the refrigerant and / or an adjustment valve for adjusting a supply amount of the refrigerant attached to the pipe for discharging the refrigerant,
The thermometer is connected to the regulating valve via a temperature controller,
The temperature of the temperature control stage is transmitted to the temperature controller by the thermometer,
When the temperature of the temperature control stage is higher than the target temperature by the temperature controller, the supply amount of the refrigerant is increased by adjusting the opening of the adjustment valve,
A distillation apparatus in which when the temperature of the temperature control stage is lower than a target temperature, the amount of refrigerant supplied is reduced by adjusting the opening of the regulating valve.
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015142718A1 (en) * | 2014-03-21 | 2015-09-24 | Ineos Europe Ag | Heads column overhead system |
CN105985262A (en) * | 2015-03-06 | 2016-10-05 | 英尼奥斯欧洲股份公司 | Improved acrylonitrile preparation |
WO2016144667A3 (en) * | 2015-03-06 | 2016-12-22 | Ineos Europe Ag | Improved acrylonitrile manufacture |
JP6300387B1 (en) * | 2016-10-21 | 2018-03-28 | 旭化成株式会社 | Acrylonitrile purification method, production method, and distillation apparatus |
WO2018074046A1 (en) * | 2016-10-21 | 2018-04-26 | 旭化成株式会社 | Purification method, production process, and distillation device for acrylonitrile |
CN112439296A (en) * | 2019-09-05 | 2021-03-05 | 中石油吉林化工工程有限公司 | Low-temperature circulation process for bottom of absorption tower of acrylonitrile device |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104922923A (en) * | 2014-03-21 | 2015-09-23 | 英尼奥斯欧洲股份公司 | Inhibitor adding head fraction tower operation |
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CN114870421A (en) * | 2015-11-16 | 2022-08-09 | 英尼奥斯欧洲股份公司 | Head fraction column pump cycle |
CN106334330B (en) * | 2016-09-28 | 2018-11-09 | 唐山钢铁集团有限责任公司 | Overhead temperature automatic adjustment control method |
JP2020121969A (en) * | 2019-01-29 | 2020-08-13 | 旭化成株式会社 | Method for purifying (meth)acrylonitrile and method for manufacturing (meth)acrylonitrile |
CN112441939B (en) * | 2019-09-05 | 2024-03-22 | 中石油吉林化工工程有限公司 | Acrylonitrile production system |
KR102482497B1 (en) * | 2020-06-16 | 2022-12-29 | 태광산업주식회사 | Distillation device and the use thereof |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002518353A (en) * | 1998-06-15 | 2002-06-25 | ソリユテイア・インコーポレイテツド | Olefinic unsaturated nitrile recovery method |
JP2010222309A (en) * | 2009-03-24 | 2010-10-07 | Asahi Kasei Chemicals Corp | Method for purifying acrylonitrile |
JP2010241742A (en) * | 2009-04-07 | 2010-10-28 | Daiyanitorikkusu Kk | Method for recovering (meth)acrylonitrile |
JP2010533578A (en) * | 2007-07-19 | 2010-10-28 | バール,フランク | How to control and cool a distillation column |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1171823A (en) * | 1967-01-20 | 1969-11-26 | G & J Weir Ltd | Water Distillation Plant. |
US3885928A (en) * | 1973-06-18 | 1975-05-27 | Standard Oil Co Ohio | Acrylonitrile and methacrylonitrile recovery and purification system |
DD125821A1 (en) * | 1976-05-21 | 1977-05-18 | ||
JPH0975604A (en) * | 1995-09-14 | 1997-03-25 | Sumitomo Chem Co Ltd | Control method for distillation tower |
JP2005028224A (en) * | 2003-07-08 | 2005-02-03 | Mitsubishi Chemicals Corp | Control method for distillation apparatus |
JP4959158B2 (en) * | 2005-08-05 | 2012-06-20 | 旭化成ケミカルズ株式会社 | Method for separating and recovering acrylonitrile |
CN201512484U (en) * | 2009-09-14 | 2010-06-23 | 郑州正力聚合物科技有限公司 | Special type acrylon purifying device |
-
2011
- 2011-12-12 WO PCT/JP2011/078706 patent/WO2012090690A1/en active Application Filing
- 2011-12-12 CN CN201180059970.3A patent/CN103261150B/en active Active
- 2011-12-12 JP JP2012550805A patent/JP5605921B2/en active Active
- 2011-12-12 KR KR1020137015540A patent/KR101528986B1/en active IP Right Grant
- 2011-12-15 TW TW100146557A patent/TWI434821B/en active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002518353A (en) * | 1998-06-15 | 2002-06-25 | ソリユテイア・インコーポレイテツド | Olefinic unsaturated nitrile recovery method |
JP2010533578A (en) * | 2007-07-19 | 2010-10-28 | バール,フランク | How to control and cool a distillation column |
JP2010222309A (en) * | 2009-03-24 | 2010-10-07 | Asahi Kasei Chemicals Corp | Method for purifying acrylonitrile |
JP2010241742A (en) * | 2009-04-07 | 2010-10-28 | Daiyanitorikkusu Kk | Method for recovering (meth)acrylonitrile |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015142718A1 (en) * | 2014-03-21 | 2015-09-24 | Ineos Europe Ag | Heads column overhead system |
EA036895B1 (en) * | 2014-03-21 | 2021-01-12 | ИНЕОС Юроп АГ | Overhead product system of forerun column |
CN105985262A (en) * | 2015-03-06 | 2016-10-05 | 英尼奥斯欧洲股份公司 | Improved acrylonitrile preparation |
WO2016144667A3 (en) * | 2015-03-06 | 2016-12-22 | Ineos Europe Ag | Improved acrylonitrile manufacture |
WO2016144664A3 (en) * | 2015-03-06 | 2017-01-26 | Ineos Europe Ag | Improved process for preparing acrylonitrile |
JP6300387B1 (en) * | 2016-10-21 | 2018-03-28 | 旭化成株式会社 | Acrylonitrile purification method, production method, and distillation apparatus |
WO2018074046A1 (en) * | 2016-10-21 | 2018-04-26 | 旭化成株式会社 | Purification method, production process, and distillation device for acrylonitrile |
US10294197B2 (en) | 2016-10-21 | 2019-05-21 | Asahi Kasei Kabushiki Kaisha | Purifying method, production method, and distillation apparatus for acrylonitrile |
RU2736379C1 (en) * | 2016-10-21 | 2020-11-16 | Асахи Касеи Кабусики Кайся | Purification method, method of producing and apparatus for distillation of acrylonitrile |
CN112439296A (en) * | 2019-09-05 | 2021-03-05 | 中石油吉林化工工程有限公司 | Low-temperature circulation process for bottom of absorption tower of acrylonitrile device |
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