JP5755995B2 - Reaction process using supercritical water - Google Patents

Description

  The present invention relates to a method and apparatus for producing 1,3-propanediol from glycerin.

  Since 1,3-propanediol is a raw material for high-quality polyester fibers such as polytrimethylene terephthalate (PTT), demand has increased in recent years. As one method for synthesizing 1,3-propanediol, an acrolein hydration / hydrogenation method shown in Non-Patent Document 1 is known. In this method, propylene, which is a petroleum raw material, is oxidized in air in the presence of a catalyst to synthesize acrolein, which is hydrated and hydrogenated, and is established as an industrial production method. However, due to the recent rise in crude oil prices, a method for synthesizing 1,3-propanediol from bio raw materials is desired.

  Although a method for chemically synthesizing 1,3-propanediol from a bio raw material has not been reported, there is a technique for synthesizing a precursor, acrolein, and one of them is Non-Patent Document 2. Non-Patent Document 2 discloses a method of synthesizing acrolein using glycerol, which is a bio raw material, using supercritical water at 400 ° C. and 35 MPa, and protons by sulfuric acid added in a small amount to supercritical water are glycerol. It is characterized by functioning as a co-catalyst that accelerates the dehydration reaction.

Japanese Patent No. 3486195 Japanese Patent No. 2735717

Manufacturing of 1,3-PDO and PTT Applications and economics CM Planet Division, August 2000 Acrolein synthesis from glycerol in hot-compressed water., Bioresource Technology 98 (2007) 1285-1290

  The method described in Non-Patent Document 2 generates allyl alcohol, which is a by-product, in addition to acrolein. For example, Patent Documents 1 and 2 disclose methods for converting acrolein to 1,3-propanediol, but when these methods are used to convert acrolein containing allyl alcohol to 1,3-propanediol, allyl The alcohol is converted to 1,2-propanediol. When PTT is polymerized using 1,3-propanediol containing 1,2-propanediol as a raw material, there is a problem that the physical properties are deteriorated due to deterioration of crystallinity of the obtained polymer.

  Therefore, an object of the present invention is to produce high-purity 1,3-propanediol by efficiently removing by-products when producing 1,3-propanediol from glycerin.

  As a result of intensive studies by the present inventors in order to achieve the above object, in the process of producing 1,3-propanediol from glycerol, acrolein is hydrated to give 3-hydroxypropionaldehyde (3-HPA). After the formation, allyl alcohol is removed, and further, 3-hydroxypropionaldehyde is subjected to a hydrogenation reaction to produce 1,3-propanediol, and then 1,2-propanediol is removed. It has been found that propanediol can be produced.

That is, the present invention includes the following.
(1) A supercritical reaction step in which glycerol is reacted with supercritical water and an acid to produce acrolein;
A hydration reaction step in which acrolein produced in the supercritical reaction step is hydrated to produce 3-hydroxypropionaldehyde;
A first removal step of removing allyl alcohol present as a by-product from 3-hydroxypropionaldehyde produced in the hydration reaction step;
A hydrogenation reaction step of producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde after the first removal step; and a by-product from 1,3-propanediol produced in the hydrogenation reaction step A second removal step of removing 1,2-propanediol present as
A process for producing 1,3-propanediol, comprising:

(2) The production method according to (1), wherein the first removal step and the second removal step are performed by distillation.
(3) The production method according to (1) or (2), wherein the hydration reaction step is performed under conditions in which acrolein is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state.

(4) The production method according to (2), wherein the hydration reaction step and the first removal step are simultaneously performed under conditions in which allyl alcohol is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state. .
(5) The manufacturing method according to (4), wherein the condition is a condition in which water exists in a gaseous state.
(6) A method for producing a polymer, comprising polymerizing 1,3-propanediol obtained by the production method according to any one of (1) to (5).

(7) A supercritical reactor that reacts glycerin with supercritical water and acid to produce acrolein;
Under conditions where allyl alcohol is present in a gaseous state and 3-hydroxypropionaldehyde is present in a liquid state, acrolein produced in a supercritical reactor is hydrated to produce 3-hydroxypropionaldehyde, and A hydration distiller that separates 3-hydroxypropionaldehyde from allyl alcohol present as a by-product;
Control means for controlling the hydration reactor to conditions where allyl alcohol is present in the gaseous state and 3-hydroxypropionaldehyde is present in the liquid state;
A hydrogenation reactor for producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde separated by a hydration reactor; and 1,3-propanediol produced by the hydrogenation reactor, A distillation column to remove 1,2-propanediol present as a by-product;
An apparatus for producing 1,3-propanediol.

(8) detection means for detecting conditions in the hydration reactor; and storage means in which allyl alcohol is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state;
Further comprising
The control means acquires the condition detected by the detection means, compares the acquired condition with the condition stored in the storage means, and sets the condition in the hydration reactor so as to match the stored condition. The manufacturing apparatus according to (7), which is controlled.

  According to the present invention, highly pure 1,3-propanediol can be produced from glycerin.

1 shows an embodiment of an apparatus for producing 1,3-propanediol. 1 illustrates one embodiment of a hydration reactor still. 1 illustrates one embodiment of a hydration reactor still. 1 shows an embodiment of an apparatus for producing 1,3-propanediol equipped with a hydration reaction distillation apparatus. 1 shows an embodiment of an apparatus for producing 1,3-propanediol equipped with a hydration reaction distillation apparatus. 1 shows an embodiment of an apparatus for producing 1,3-propanediol equipped with a hydration reaction distillation apparatus. 1 shows an embodiment of an apparatus for producing 1,3-propanediol equipped with a hydration reaction distillation apparatus. A hydration reaction distiller provided with a control means 46, a detection means 47, and a storage means 48 is shown. The flowchart of the manufacturing method of 1, 3- propanediol is shown. The flowchart of the manufacturing method of 1, 3- propanediol is shown.

Hereinafter, the present invention will be described in detail.
(1) Method for producing 1,3-propanediol The method for producing 1,3-propanediol of the present invention is:
A supercritical reaction step of reacting glycerin with supercritical water and acid to produce acrolein;
A hydration reaction step in which acrolein produced in the supercritical reaction step is hydrated to produce 3-hydroxypropionaldehyde;
A first removal step of removing allyl alcohol present as a by-product from 3-hydroxypropionaldehyde produced in the hydration reaction step;
A hydrogenation reaction step of producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde after the first removal step; and a by-product from 1,3-propanediol produced in the hydrogenation reaction step A second removal step of removing 1,2-propanediol present as
(FIG. 9).

  The production method of the present invention is not limited to the above-described steps, and may further include arbitrary steps. For example, a cooling process, a decompression process, a heating process, a precipitate removing process, and the like may be appropriately performed.

Supercritical reaction step In the supercritical reaction step, glycerol is converted to acrolein by reacting with supercritical water and acid.

  The conditions for the supercritical reaction step are not particularly limited as long as water is in a supercritical state. Since the critical point of water is 374 ° C. and 22.1 MPa, the reaction temperature is 374 ° C. or higher, more preferably 400 ° C. or higher, most preferably 453 ° C. or higher, and the reaction pressure is 22.1 MPa or higher, more preferably 34.5 MPa. That's it. Although the upper limit of reaction temperature is not specifically limited, It is preferable that it is 600 degrees C or less, and it is more preferable that it is 500 degrees C or less. The upper limit of the reaction pressure is not particularly limited, but is preferably 50 MPa or less.

  It is also preferable to carry out the supercritical reaction step under reaction conditions in which both water and glycerin are in a supercritical state. Under these conditions, the solubility of glycerin in water increases, and glycerin can be reacted at a high concentration. Thereby, the amount of energy per raw material can be reduced, and the manufacturing cost can be reduced. The critical point of glycerin is 453 ° C. and 6.68 MPa.

  The reaction time in the supercritical reaction step is not particularly limited as long as the generated acrolein is not decomposed. For example, 0.1 second to 60 seconds are preferable, 0.5 second to 30 seconds are more preferable, and 1 to 10 seconds are most preferable.

  The amount of glycerin is preferably at least 14% by weight, more preferably at least 20% by weight, most preferably at least 50% by weight, preferably at most 70% by weight, based on the mixture of glycerin, water and acid. .

  The kind of acid is not particularly limited. For example, an inorganic acid and an organic acid can be mentioned, More specifically, a sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, benzenesulfonic acid etc. can be mentioned.

The amount of the acid is preferably 6.3 × 10 ^{−3 to} 1.8 × 10 ⁻¹ times the glycerin mol concentration in terms of hydrogen ion concentration. Specifically, when the glycerin concentration is 14% by weight (1.57 mol / L), the sulfuric acid concentration is 0.005 to 0.142 mol / L, and when the glycerin concentration is 50% by weight (6.11 mol / L). The sulfuric acid concentration is preferably 0.0193 to 0.549 mmol / L.

Hydration reaction step In the hydration reaction step, acrolein obtained in the supercritical reaction step is converted into 3-hydroxypropionaldehyde (3-HPA).

  The hydration reaction can be carried out using a metal catalyst. Examples of the metal species of the metal catalyst include mercury, iridium, platinum, palladium, rhodium, nickel, cobalt, chromium, vanadium, and molybdenum. The metal catalyst may contain only one kind of the above metals, or may contain a plurality of kinds in combination. Moreover, a hydration reaction can also be carried out using an ion exchange resin.

  Although the conditions of a hydration reaction process are not specifically limited, For example, the conditions of 30-120 degreeC and 0.1-0.2 MPa can be mentioned. The weight ratio of acrolein and water is not particularly limited, and examples thereof include a range of 1: 2 to 1:20.

  The hydration reaction step is preferably carried out under conditions where acrolein is present in a gaseous state and 3-hydroxypropionaldehyde is present in a liquid state. Under this condition, 3-hydroxypropionaldehyde produced by the hydration reaction falls as a liquid and is separated from gaseous acrolein. Since the hydration reaction is an equilibrium reaction, the produced 3-hydroxypropionaldehyde is continuously separated, whereby the reaction can be promoted, and the production of by-products can be further suppressed.

  Although the boiling point varies depending on the pressure, the boiling point of acrolein is lower than that of 3-hydroxypropionaldehyde at normal pressure. Those skilled in the art can set desired conditions by appropriately adjusting the pressure and temperature.

First Removal Step In the first removal step, allyl alcohol as a by-product is removed from 3-hydroxypropionaldehyde obtained in the hydration reaction step.

  The method for removing allyl alcohol is not particularly limited, but it is preferably removed by distillation. Since the boiling point of allyl alcohol is lower than that of 3-hydroxypropionaldehyde, only allyl alcohol can be vaporized and separated.

  The first removal step can be performed simultaneously with the hydration reaction step (FIG. 10). For example, under conditions where allyl alcohol is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state, more specifically, water is present in a gas state, and 3-hydroxypropionaldehyde is present in a liquid state. By performing a hydration reaction under the conditions, the produced 3-hydroxypropionaldehyde can be dropped as a liquid and separated from gaseous allyl alcohol. Under these conditions, acrolein also exists as a gas, so that 3-hydroxypropionaldehyde can be separated from acrolein.

  Therefore, as described above, the promotion of the hydration reaction and the suppression of the production of by-products can be achieved. Moreover, it is not necessary to separately install a reactor for the hydration reaction step and a distiller for the first removal step, and the equipment cost can be suppressed.

  Although the boiling point varies depending on the pressure, the boiling point at normal pressure increases in the order of acrolein, allyl alcohol, water, and 3-hydroxypropionaldehyde. Those skilled in the art can set desired conditions by appropriately adjusting the pressure and temperature.

Hydrogenation reaction step In the hydrogenation reaction, 3-hydroxypropionaldehyde after the first removal step is converted to 1,3-propanediol.

  The hydrogenation reaction can be performed using a catalyst under a hydrogen atmosphere. Examples of the catalyst include heterogeneous catalysts (suspension catalysts, fixed bed catalysts, etc.), homogeneous catalysts, and the like.

  The conditions for the hydrogenation reaction step are not particularly limited, but are preferably 30 to 150 ° C, particularly 60 to 130 ° C, and preferably 2 to 20 MPa, particularly 5 to 16 MPa.

Second Removal Step In the second removal step, 1,2-propanediol as a by-product is removed from 1,3-propanediol produced in the hydrogenation reaction step.

  The method for removing 1,2-propanediol is not particularly limited, but it is preferably removed by distillation. Since the boiling point of 1,2-propanediol is lower than that of 1,3-propanediol, only 1,2-propanediol can be vaporized and separated.

  By removing the by-product in the first removal step and the second removal step, high-purity 1,3-propanediol can be produced. A high-quality polymer can be produced by polymerizing high-purity 1,3-propanediol. “Polymerization” in the present invention includes both monopolymerization and copolymerization.

  As a preferable polymer produced using high-purity 1,3-propanediol, for example, polytrimethylene terephthalate (PTT) which is a copolymer of 1,3-propanediol and terephthalic acid can be exemplified.

(2) 1,3-propanediol production apparatus The 1,3-propanediol production apparatus of the present invention is:
A supercritical reactor (eg, piping) that reacts glycerin with supercritical water and acid to produce acrolein;
Conditions under which allyl alcohol is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state (preferably under conditions where water is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state). Hydration reaction distiller which hydrates acrolein produced in a supercritical reactor to produce 3-hydroxypropionaldehyde and separates 3-hydroxypropionaldehyde from allyl alcohol present as a by-product ;
A condition in which allyl alcohol is present in a gaseous state and 3-hydroxypropionaldehyde is present in a liquid state (preferably water is present in a gaseous state and 3-hydroxypropionaldehyde is liquid Control means to control the condition existing in the state);
A hydrogenation reactor for producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde separated by a hydration reactor; and 1,3-propanediol produced by the hydrogenation reactor, A distillation column to remove 1,2-propanediol present as a by-product;
Is provided.

In a preferred embodiment, the apparatus for producing 1,3-propanediol is as shown in FIG.
Detection means 47 for detecting conditions in the hydration reactor; and conditions in which allyl alcohol is present in the gaseous state and 3-hydroxypropionaldehyde is present in the liquid state (eg temperature and pressure), and / or Storage means 48 in which the condition that water exists in a gaseous state and 3-hydroxypropionaldehyde exists in a liquid state is stored;
Is further provided.

  The control unit 46 acquires the condition detected by the detection unit 47, compares the acquired condition with the condition stored in the storage unit 48, and sets the condition in the hydration reactor so as to match the stored condition. Control.

  The conditions in the hydration reactor can be changed, for example, when the control means controls the flow rate adjusting means 49 (for example, a valve) to adjust the supply amount of acrolein or water. Moreover, the heating means 50 and the cooling means 51 are provided with respect to the hydration reactor, and the conditions in the hydration reactor can be changed by the control means controlling them.

  An example of the control means 46 is a computer. The function of the control means can be realized by the operation of a program stored in a RAM, ROM, HDD or the like of the computer.

Examples of the detection means 47 include a conventional thermometer and pressure gauge.
Examples of the storage means 48 include RAM, ROM, HDD, and the like.

  Hereinafter, an embodiment of a production apparatus for 1,3-propanediol will be described in detail with reference to FIG. In addition, in FIG. 1, the hydration reaction distiller 45 is not used, and the hydration reactor 16 and the distillation column 17 are installed instead. On the other hand, the apparatus for producing 1,3-propanediol shown in FIGS.

  From the upstream side of the reaction path, the production apparatus is pump 1, pump 2, heater 3, heater 4, heater 5, filter 6, cooler 7, pressure reducing valve 8, cooler 9, cooler 10, pressure reducing valve 11, distillation column 12. , Heat exchanger 13, distillation tower 14, reboiler 15, hydration reactor 16, distillation tower 17, reboiler 18, hydrogenation reactor 19, hydrogen separator 20, evaporator 21, distillation tower 22, reboiler 23, heat exchange The unit 24, the distillation column 25, the reboiler 26, the heat exchanger 27, the distillation column 28, and the heat exchanger 29 are arranged in this order.

  Supercritical water and acid pressurized to 22 to 50 MPa with pumps 1 and 2 are allowed to act on glycerin, and then cooling is performed in a plurality of times.

  For reaction quenching to a reaction liquid obtained by allowing supercritical water and acid to act on glycerin to a temperature at which the main reaction stops and the viscosity of high viscosity components such as tar contained in the reaction liquid is sufficiently low Cooling water is injected and cooled (first cooling). Thereby, an increase in the viscosity and adhesion of high viscosity components such as tar can be suppressed while reducing the amount of by-product generated, and a state where solid contents such as carbon particles are not aggregated can be maintained. In the state of not agglomerating, the particle size of the solid content is several μm to several tens of μm and the adhesion is extremely small, so that the piping is not blocked. Also, the effect of increasing the differential pressure due to the solid matter adhering to the separation surface can be reduced during the operation of separating and removing the solid matter. For this reason, the maintenance frequency of the separation apparatus such as switching of the plant operation system and filter backwash operation is remarkably reduced, and the energy loss due to the stop and restart is reduced, so that the operation cost can be reduced. In addition, since the solid content is separated after the high-temperature reaction liquid such as 400 ° C. is cooled, the thermal degradation of the separation device can be prevented.

  The viscosity of the reaction liquid after the first cooling is desirably 0.1 Pa · s or less, and a temperature at which such low viscosity can be realized, specifically, 100 ° C. or more is desirable. On the other hand, a temperature of 200 ° C. or lower is desirable to completely stop the synthesis reaction and the thermal decomposition reaction. Therefore, the first cooling temperature is desirably 100 to 200 ° C. As a first cooling method, the cooling water is directly mixed with the reaction liquid, thereby speeding up the temperature change compared to heat exchange from the periphery of the pipe by a jacket or the like. As a result, the thermal decomposition reaction can be stopped at a high speed, and the generated acrolein can be stopped from changing to by-products such as tar and carbon particles, so that an improvement in raw material yield can be expected. Moreover, since the amount of by-products generated is reduced, it is possible to contribute to blockage of piping and equipment, suppression of erosion, and precise pressure control.

  Next, after the solid content is separated and removed from the reaction solution, the reaction solution is cooled using the cooler 7 to a temperature below the boiling point of water and the tar content in the reaction solution is not fixed to the equipment (second cooling). . By reducing the pressure using the pressure reducing valve 8 after that, it is possible to avoid clogging due to the solid content in the pipe and the valve and to reduce the adhesion of the tar content, so that the pressure control accuracy in the pressure reducing valve 8 is improved. In particular, since the opening of the pressure reducing valve is extremely narrow, it is very effective that the opening / closing operation of the valve is easy and stabilized by suppressing the adhesion of not only the solid content but also the tar content. In addition, since the cooling temperature is set to be equal to or lower than the boiling point of water, it is possible to suppress the reaction liquid from being vaporized and the volume from rapidly expanding after depressurization, so that the safety of the reaction apparatus can be improved.

  The viscosity of the reaction liquid after the second cooling is desirably 10 Pa · s or less, and a temperature at which such low viscosity can be realized, specifically 53 ° C. or more, particularly 80 ° C. or more is desirable. On the other hand, the temperature is preferably 100 ° C. or less from the viewpoint of suppressing vaporization and rapid expansion of the reaction solution after decompression. For this reason, the second cooling temperature is 53-100 ° C., preferably 80-100 ° C., considering that it is at least the boiling point of acrolein.

  After reducing the pressure, the reaction solution is cooled to the boiling point of the target substance using the coolers 9 and 10 (third cooling). In other words, the temperature of the third cooling step is maintained above the boiling point of the target substance. Thereby, the target substance is easily vaporized from the discharged reaction solution. For this reason, the energy efficiency at the time of reheating in the latter distillation process can be improved. Considering that the boiling point is higher than the boiling point of acrolein, the third cooling temperature is in the range of 53 ° C. to the second cooling temperature. The cooled reaction liquid is depressurized by the pressure reducing valve 11 and then sent to the distillation column 12.

  By carrying out from the supercritical reaction to the separation and removal of solids in a vertical pipe partitioned by a valve, the reaction liquid containing by-products flows down uniformly in the circumferential direction of the pipe by gravity. In the case of a horizontal system, the solid content in the generated by-product accumulates at the bottom of the pipe, and erosion occurs at the bottom of the pipe, pressure reducing valve, etc. due to friction accompanying the flow. By flowing down uniformly with respect to the circumferential direction of the piping, the contact with the solid particles on the inner surface of the piping is smoothed, and a further erosion reduction effect is obtained. In addition, by preparing two or more reactors and solid content separators from the heater 3 to the filter 6, alternating operation and alternate discharge of by-product particles are possible. As a result, when maintenance work is being performed in a certain system, it is possible to maintain a state in which at least one other system is operating, so it is not necessary to stop the entire plant, and continuous operability is improved. . At that time, the heater 3 in the previous stage of the reaction apparatus has a longer residence time and a larger equipment scale than the heater 5 of the reaction pipe. Further, since there is no organic material such as glycerin as a raw material in the heater 3, no by-product is generated. This shows that while the heater 3 has a large energy use ratio in the entire process, there is very little concern about troubles caused by by-products compared to the downstream process. Therefore, when considering a system of multiple systems, there is a system in which the heater 3 performs maintenance work in the downstream process by using the heater 3 in common with each system and branching from the reaction piping to the multiple systems. Can be operated continuously. As a result, energy loss due to stop / restart can be minimized, so that both the equipment cost and the operation cost can be reduced.

  The reaction solution flowing into the distillation column 12 is separated by distillation, and the reaction solution containing acrolein, water, acetaldehyde, formaldehyde, allyl alcohol and the like is discharged from the top, and the waste water containing water, sulfuric acid, tar and the like is discharged from the bottom. The reaction solution is cooled by the heat exchanger 13 and then flows into the distillation column 14. The reaction solution flowing into the distillation column 14 is separated by distillation, and a waste solution containing acetaldehyde and formaldehyde is discharged from the top, and a reaction solution containing acrolein, water, allyl alcohol, and the like is discharged from the bottom. The reaction liquid discharged from the distillation column 14 flows into the reboiler 15 and is heated to 40 to 110 ° C., preferably 50 to 70 ° C. near the reaction temperature of the hydration reaction in order to hydrate the acrolein.

  After adding water, the reaction liquid flowing into the hydration reactor 16 is mainly converted into 3-hydroxypropionaldehyde (3-HPA) by a hydration reaction. In the hydration reaction, a catalyst containing one or more kinds of metals, for example, mercury, iridium, platinum, palladium, rhodium, nickel, cobalt, chromium, vanadium, molybdenum, or an ion exchange resin is used, and the reaction temperature is 30 to 120. The weight ratio of acrolein to water can be in the range of 1: 2 to 1:20 at a pressure of 0.1 to 0.2 MPa. The reaction liquid discharged from the hydration reactor flows into the distillation column 17 and is separated by distillation. The waste liquid containing acrolein, water, allyl alcohol, and the like is discharged from the top, and the reaction containing 3-HPA, water, and the like from the bottom. Drain the liquid. After the waste liquid is cooled by the heat exchanger 36, a part thereof is refluxed to the hydration reactor 16. The reaction solution is heated to 30 to 150 ° C., preferably 60 to 130 ° C., in the vicinity of the reaction temperature of the hydrogenation reaction in order to cause hydrogenation reaction of 3-HPA with the reboiler 18.

  After water is added as necessary, the reaction liquid flowing into the hydrogenation reactor 19 is hydrogenated by a catalyst. The catalyst is heterogeneous and is used by itself or supported on a support and is preferably a fixed bed, but a homogeneous catalyst can also be used. When a suspension catalyst is used, a Raney-nickel catalyst or a noble metal catalyst finely dispersed and supported on a carrier is suitable. In the case of using a fixed bed catalyst, a catalyst in which a noble metal such as platinum, palladium, rhodium or the like, a metal such as nickel, copper, chromium or zinc is finely dispersed and supported on a support such as titanium oxide, alumina, silica or zeolite. Alternatively, a zeolite such as ZSM-5 is preferable. The reaction temperature is preferably 30 to 150 ° C, particularly 60 to 130 ° C, and the pressure is preferably 2 to 20 MPa, particularly 5 to 16 MPa.

  The reaction liquid discharged from the hydrogenation reactor flows into the hydrogen separator 20 to separate the hydrogen and the reaction liquid. The separated hydrogen is refluxed to the hydrogenation reactor. The reaction liquid flows into the evaporator 21 and is separated from some water. The separated water is refluxed to the hydration reactor or hydrogenation reactor. The reaction liquid flows into the distillation column 22 and is separated by distillation. The waste liquid containing water and the like is discharged from the top, and 1,3-propanediol (1,3-PDO) and 1,2-propanediol (1 , 2-PDO), 4-oxa-1,7heptanediol and the like are discharged. After the waste liquid is cooled by the heat exchanger 37, a part thereof is refluxed to the hydration reactor 16 and the hydrogenation reactor 19. The reaction liquid flows into the distillation column 25 through the reboiler 23 and the heat exchanger 24 and is separated by distillation. The liquid waste containing 1,2-propanediol is discharged from the top, and 1,3-propanediol, 4- The reaction solution containing oxa-1,7heptanediol and the like is discharged. The reaction liquid flows into the distillation column 28 through the reboiler 26 and the heat exchanger 27 and is separated by distillation. 1,3-propanediol is discharged from the top, and 4-oxa-1,7heptanediol and the like are contained from the bottom. Drain the waste liquid.

  The waste liquid flows into the distillation column 41 through the reboiler 39 and the heat exchanger 40 and is separated by distillation. The 4-oxa-1,7heptanediol is discharged from the top and the heavy component is discharged from the bottom. 4-Oxa-1,7heptanediol is hydrolyzed by the catalyst in the hydrolysis reactor 44 through the heat exchangers 42 and 43 to become 1,3-propanediol. The catalyst is heterogeneous and is used by itself or supported on a support and is preferably a fixed bed, but a homogeneous catalyst can also be used. When a suspension catalyst is used, a noble metal catalyst finely dispersed and supported on a support is suitable. In the case of using a fixed bed catalyst, a catalyst in which a noble metal such as platinum, palladium, rhodium or the like, a metal such as nickel, copper, chromium or zinc is finely dispersed and supported on a support such as titanium oxide, alumina, silica or zeolite. Alternatively, a zeolite such as ZSM-5 is preferable. The reaction temperature is preferably 30 to 300 ° C, particularly 60 to 260 ° C, and the pressure is preferably 0.1 to 10 MPa, particularly 1 to 6 MPa.

  Waste water containing tar, sulfuric acid, and the like kept warm by the reboiler 30 flows into the solid content removing device 31, and the solid content is removed. Since the waste water is maintained at a temperature range of 50 to 100 ° C., preferably 80 to 100 ° C. in which the fluidity can be maintained, the solid content removing device collects solids such as carbon particles and has a high viscosity such as tar. Adhesion of components is suppressed. A filter, a cyclone, a sedimentation tank, etc. can be used for removal of solid content.

  The waste water discharged from the solid content removing device 31 flows into the organic matter removing device 32, and the organic matter in the waste water is removed. Removal of organic substances is performed by adsorption, and activated carbon, zeolite, or the like can be used as an adsorbent. Thereby, tar and other organic substances contained in the wastewater are removed.

  Waste water discharged from the organic substance removing device 32 flows into the ion exchange tower 33, and an acid such as sulfuric acid contained in the waste water is removed by the ion exchange resin.

  Water purified from the solid content removing device 31 to the ion exchange tower 33 flows into the water tank 34 and is reused as raw water or cooling water for reaction quenching. Thereby, the usage-amount of water can be reduced and it becomes possible to suppress plant operation cost. In addition, a wastewater treatment facility necessary for discharging wastewater containing chemical substances designated as poisonous substances such as acrolein and formaldehyde to the outside of the system becomes unnecessary, which can contribute to reduction of equipment cost and operation cost.

  By preparing two or more systems from the solid content removing device 31 to the ion exchange column 33, it is possible to perform alternate operation and alternate discharge of impurities. As a result, when performing maintenance work in a certain system, it is possible to maintain a state in which at least one other system is operating, so it is not necessary to stop the entire plant, and continuous operability is improved. .

  In the hydration reaction, a hydration distillation apparatus as shown in FIG. 2 can be used. The 3-HPA produced by flowing acrolein and water into the hydration reactor as a gas and performing the hydration reaction becomes liquid because it has a higher boiling point than water and acrolein and falls to the bottom of the hydration reactor. To do. Since the hydration reaction is an equilibrium reaction, the 3-HPA is continuously removed from the atmosphere as a liquid, whereby the reaction is promoted and the residence time can be shortened compared to the conventional apparatus. Moreover, the production | generation of a by-product can be suppressed by shortening residence time. Further, since 3-HPA and water and acrolein are separated in the hydration reaction distillation apparatus, the distillation tower on the downstream side of the hydration reaction such as the distillation tower 17 in FIG. 1 can be omitted, and the equipment cost is reduced. Contribute to In addition, it is possible to omit the distillation column upstream of the hydration reaction such as the distillation column 14 in FIG.

  In the hydration reaction, when the reaction is carried out at a boiling point of acrolein or more and less than the boiling point of water, a hydration reaction distillation apparatus as shown in FIG. 3 can be used. Acrolein is introduced as a gas from the lower part of the hydration reactor, and water is introduced as a liquid from the upper part of the hydration reactor. Since it is desirable to distribute water uniformly in the atmosphere, it can be sprayed into the hydration reactor using a shower or the like. 3-HPA produced by the hydration reaction becomes a liquid and falls to the bottom of the hydration reaction still with water. Since the hydration reaction is an equilibrium reaction, the 3-HPA is continuously removed from the atmosphere as a liquid, whereby the reaction is promoted and the residence time can be shortened compared to the conventional apparatus. Moreover, the production | generation of a by-product can be suppressed by shortening residence time. Further, since 3-HPA and water and acrolein are separated in the reactor, a distillation column on the downstream side of the hydration reaction such as the distillation column 17 in FIG. 1 can be omitted, which contributes to a reduction in equipment cost. In addition, it is possible to omit the distillation column upstream of the hydration reaction such as the distillation column 14 in FIG. The mixing of water into 3-HPA is not a problem because water is required in the downstream hydrogenation reaction.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, the scope of the present invention is not limited to this.

Example 1
Using the apparatus shown in FIG. 1, a supercritical reaction was carried out under the conditions of a raw material glycerin concentration of 15 wt%, a reaction temperature of 400 ° C., a reaction pressure of 35 MPa, and a reaction time of 2 s. From 200 ° C. to 125 ° C., pressure reducing valve 8 from 35 MPa to 0.35 MPa, cooling device 9 from 125 ° C. to 95 ° C., cooling device 10 from 95 ° C. to 60 ° C., pressure reducing valve 11 large The pressure was reduced to atmospheric pressure. After performing the hydration reaction under the conditions of a reaction temperature of 60 ° C., a reaction pressure of 0.1 MPa, and a reaction time of 1 h, the hydrogenation reaction is performed under the conditions of a reaction temperature of 60 to 120 ° C., a reaction pressure of 15 MPa, and a reaction time of 1 h. 1,3-propanediol was synthesized. As a result, in the obtained reaction solution, the yield of 1,3-propanediol was 52%, and 1,2-propanediol was not detected.

(Example 2)
A supercritical reaction was carried out under the conditions of a raw material glycerin concentration of 15 wt%, a reaction temperature of 400 ° C., a reaction pressure of 35 MPa, and a reaction time of 2 s using an apparatus including the hydration distillation apparatus 45 shown in FIG. 200 ° C by quenching, cooling from 200 ° C to 125 ° C by cooler 7, reducing pressure from 35 MPa to 0.35 MPa by pressure reducing valve 8, cooling from 125 ° C to 95 ° C by cooler 9, and 95 ° C to 60 ° C by cooler 10 The pressure was reduced to atmospheric pressure with the pressure reducing valve 11. After performing the hydration reaction under the conditions of a reaction temperature of 60 ° C., a reaction pressure of 0.1 MPa, and a reaction time of 1 h, the hydrogenation reaction is performed under the conditions of a reaction temperature of 60 to 120 ° C., a reaction pressure of 15 MPa, and a reaction time of 1 h. 1,3-propanediol was synthesized. As a result, in the obtained reaction solution, the yield of 1,3-propanediol was 55%, and 1,2-propanediol was not detected.

(Example 3)
A supercritical reaction was carried out under the conditions of a raw material glycerin concentration of 15 wt%, a reaction temperature of 400 ° C., a reaction pressure of 35 MPa, and a reaction time of 2 s using an apparatus including the hydration distillation apparatus 45 shown in FIG. 200 ° C by quenching, cooling from 200 ° C to 125 ° C by cooler 7, reducing pressure from 35 MPa to 0.35 MPa by pressure reducing valve 8, cooling from 125 ° C to 95 ° C by cooler 9, and 95 ° C to 60 ° C by cooler 10 The pressure was reduced to atmospheric pressure with the pressure reducing valve 11. After performing the hydration reaction under the conditions of a reaction temperature of 60 ° C., a reaction pressure of 0.1 MPa, and a reaction time of 1 h, the hydrogenation reaction is performed under the conditions of a reaction temperature of 60 to 120 ° C., a reaction pressure of 15 MPa, and a reaction time of 1 h. 1,3-propanediol was synthesized. As a result, in the obtained reaction solution, the yield of 1,3-propanediol was 57%, and 1,2-propanediol was not detected.

Example 4
A supercritical reaction was carried out under the conditions of a raw material glycerin concentration of 15 wt%, a reaction temperature of 400 ° C., a reaction pressure of 35 MPa, and a reaction time of 2 s using an apparatus including the hydration distillation apparatus 45 shown in FIG. 200 ° C by quenching, cooling from 200 ° C to 125 ° C by cooler 7, reducing pressure from 35 MPa to 0.35 MPa by pressure reducing valve 8, cooling from 125 ° C to 95 ° C by cooler 9, and 95 ° C to 60 ° C by cooler 10 The pressure was reduced to atmospheric pressure with the pressure reducing valve 11. After performing the hydration reaction under the conditions of a reaction temperature of 60 ° C., a reaction pressure of 0.1 MPa, and a reaction time of 1 h, the hydrogenation reaction is performed under the conditions of a reaction temperature of 60 to 120 ° C., a reaction pressure of 15 MPa, and a reaction time of 1 h. 1,3-propanediol was synthesized. As a result, in the obtained reaction solution, the yield of 1,3-propanediol was 55%, and 1,2-propanediol was not detected.

(Example 5)
A supercritical reaction was carried out under the conditions of a raw material glycerin concentration of 15 wt%, a reaction temperature of 400 ° C., a reaction pressure of 35 MPa, and a reaction time of 2 s using an apparatus including the hydration distillation apparatus 45 shown in FIG. 200 ° C by quenching, cooling from 200 ° C to 125 ° C by cooler 7, reducing pressure from 35 MPa to 0.35 MPa by pressure reducing valve 8, cooling from 125 ° C to 95 ° C by cooler 9, and 95 ° C to 60 ° C by cooler 10 The pressure was reduced to atmospheric pressure with the pressure reducing valve 11. After performing the hydration reaction under the conditions of a reaction temperature of 60 ° C., a reaction pressure of 0.1 MPa, and a reaction time of 1 h, the hydrogenation reaction is performed under the conditions of a reaction temperature of 60 to 120 ° C., a reaction pressure of 15 MPa, and a reaction time of 1 h. 1,3-propanediol was synthesized. As a result, in the obtained reaction solution, the yield of 1,3-propanediol was 57%, and 1,2-propanediol was not detected.

(Comparative example)
1,3-propanediol synthesis was performed using the same parameters as in Example 1. However, allyl alcohol recovery in the distillation column 17 and 1,2-propanediol recovery in the distillation column 25 were not performed. As a result, 1% of 1,2-propanediol was detected from the reaction solution.

1, 2 Pump 3, 4, 5 Heater 6 Filter 7, 9, 10 Cooler 8, 11 Pressure reducing valve 12, 14, 17, 22, 25, 28, 41 Distillation tower 13, 24, 27, 29, 35, 36 , 37, 38, 40, 42, 43 Heat exchanger 15, 18, 23, 26, 30, 39 Reboiler 16 Hydration reactor 19 Hydrogenation reactor 20 Hydrogen separator 21 Evaporator 31 Solid content removal device 32 Organic content Removal device 33 Ion exchange tower 34 Water tank 44 Hydrolysis reactor 45 Hydration reaction distiller 46 Control means 47 Detection means 48 Storage means 49 Flow rate adjustment means 50 Heating means 51 Cooling means

Claims (8)

A supercritical reaction step of reacting glycerin with supercritical water and acid to produce acrolein;
A hydration reaction step in which acrolein produced in the supercritical reaction step is hydrated to produce 3-hydroxypropionaldehyde;
A first removal step of removing allyl alcohol present as a by-product from 3-hydroxypropionaldehyde produced in the hydration reaction step;
A hydrogenation reaction step of producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde after the first removal step; and a by-product from 1,3-propanediol produced in the hydrogenation reaction step A second removal step of removing 1,2-propanediol present as
A process for producing 1,3-propanediol, comprising:   The manufacturing method of Claim 1 which implements a 1st removal process and a 2nd removal process by distillation.   The production method according to claim 1 or 2, wherein the hydration reaction step is performed under conditions in which acrolein is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state.   The production method according to claim 2, wherein the hydration reaction step and the first removal step are simultaneously performed under conditions in which allyl alcohol is present in a gas state and 3-hydroxypropionaldehyde is present in a liquid state.   The manufacturing method according to claim 4, wherein the condition is a condition in which water exists in a gaseous state.   The manufacturing method of a polymer including superposing | polymerizing the 1, 3- propanediol obtained by the manufacturing method of any one of Claims 1-5. A supercritical reactor that reacts glycerin with supercritical water and acid to produce acrolein;
Under conditions where allyl alcohol is present in a gaseous state and 3-hydroxypropionaldehyde is present in a liquid state, acrolein produced in a supercritical reactor is hydrated to produce 3-hydroxypropionaldehyde, and A hydration distiller that separates 3-hydroxypropionaldehyde from allyl alcohol present as a by-product;
Control means for controlling the hydration reactor to conditions where allyl alcohol is present in the gaseous state and 3-hydroxypropionaldehyde is present in the liquid state;
A hydrogenation reactor for producing 1,3-propanediol by hydrogenation reaction of 3-hydroxypropionaldehyde separated by a hydration reactor; and 1,3-propanediol produced by the hydrogenation reactor, A distillation column to remove 1,2-propanediol present as a by-product;
An apparatus for producing 1,3-propanediol. Detection means for detecting conditions in the hydration reactor; and storage means in which allyl alcohol is present in the gas state and 3-hydroxypropionaldehyde is present in the liquid state;
Further comprising
The control means acquires the condition detected by the detection means, compares the acquired condition with the condition stored in the storage means, and sets the condition in the hydration reactor so as to match the stored condition. The manufacturing apparatus according to claim 7, which is controlled.

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