JP4866709B2 - Method for producing carboxylic acid polymer - Google Patents

Description

  The present invention relates to a method for producing a carboxylic acid polymer and a polymer production apparatus used therefor.

  As a method for producing a carboxylic acid polymer in which free radicals are generated by the reaction of hydrogen sulfite and oxygen and polymerization is performed in the presence of the redox initiator of the free radicals, polymerization is performed by a dropping method in a stirred tank reactor. A method and a method of performing polymerization by forming a thin film flow in a reaction tube are known.

In Patent Document 1, (A) an aqueous solution of a monomer containing an α-unsaturated carboxylic acid or a salt thereof, an aqueous solution containing a bisulfite, and a gas containing oxygen are introduced into a flow mixer. A first polymerization reaction step for polymerizing the monomer, and (B) a reaction product obtained in the first polymerization reaction step, which introduces a reaction product containing an unreacted monomer through a pipe and further polymerizes, at least a gas-liquid mixing mechanism; A method for producing a carboxylic acid polymer having a second polymerization reaction step having a temperature control mechanism is disclosed.
Japanese Patent No. 3730615

  By the way, when the reaction fluid of gas-liquid two-phase flow circulates in the piping, there is a problem that significant vibration may occur in the piping.

  An object of the present invention is to suppress vibration of a pipe through which a gas-liquid two-phase reaction fluid flows when polymerizing a carboxylic acid polymer in the presence of a redox initiator of bisulfite and oxygen. It is.

  The inventors of the present invention have found that the vibration of the pipe is caused by the fact that the gas-liquid two-phase flow reaction fluid flows through the pipe in the slag flow state, and have arrived at the present invention.

The method for producing the carboxylic acid polymer of the present invention that achieves the above object
Carboxylic acid heavy polymer which introduces a reaction fluid comprising an aqueous solution of a monomer containing α-unsaturated carboxylic acid or a salt thereof, an aqueous solution containing hydrogen sulfite, and a gas containing oxygen into the polymerization reactor to polymerize the monomer. A manufacturing method of coalescence,
The reaction fluid flowing through the piping portion is pressurized at least in the piping portion that communicates with the open pipe end through which the gas-liquid two-phase flow reaction fluid containing the gas containing oxygen flows.

The carboxylic acid polymer production apparatus of the present invention is
a monomer aqueous solution source for supplying an aqueous solution of a monomer containing an α-unsaturated carboxylic acid or a salt thereof;
An aqueous bisulfite solution source for supplying an aqueous solution containing bisulfite;
An oxygen-containing gas supply source for supplying a gas containing oxygen;
A reaction fluid comprising a monomer aqueous solution from the monomer aqueous solution source, a hydrogen sulfite aqueous solution from the hydrogen sulfite aqueous solution source, and an oxygen-containing gas from the oxygen-containing gas supply source is supplied, and the reaction fluid is mixed. And a polymerization reactor for polymerizing the monomer,
With
A gas-liquid two-phase flow reaction fluid containing oxygen-containing gas flows at least in a pipe portion connected to the open pipe end, and further includes a pressurizing means for pressurizing the reaction fluid flowing through the pipe portion. Is.

  According to the present invention, the reaction fluid flowing through the piping portion is pressurized at least in the piping portion leading to the open pipe end through which the gas-liquid two-phase flow reaction fluid containing the gas containing oxygen flows. The reaction fluid becomes closer to the bubble flow state than the slag flow state, thereby suppressing the vibration of the pipe portion.

  Hereinafter, embodiments will be described in detail.

  The method for producing a carboxylic acid polymer according to the present embodiment polymerizes a reaction fluid comprising an aqueous solution of a monomer containing an α-unsaturated carboxylic acid or a salt thereof, an aqueous solution containing a bisulfite, and a gas containing oxygen. The product is introduced into the reactor to polymerize the monomer, and the product is recovered. At that time, the reaction fluid flowing through a predetermined pipe portion is pressurized.

  As an example of the specific embodiment, (A) a first polymerization reaction step in which a reaction fluid is introduced into a first reactor to polymerize a monomer, and (B) an unreacted monomer obtained in the first polymerization reaction step. And a second polymerization reaction step of introducing an unreacted monomer into the second reactor and further polymerizing the unreacted monomer. In this embodiment, the polymerization reactor is composed of two reactors, a first reactor and a second reactor.

<First polymerization reaction step>
In the first polymerization reaction step, a reaction fluid comprising an aqueous solution of a monomer containing an α-unsaturated carboxylic acid or a salt thereof, an aqueous solution containing a bisulfite, and a gas containing oxygen is introduced into the first reactor. The monomer is polymerized.

  The monomer in the monomer aqueous solution (hereinafter referred to as “monomer aqueous solution”) is mainly α-unsaturated carboxylic acid or a salt thereof. Among the α-unsaturated carboxylic acids or salts thereof, monomers having acrylic acid or a salt thereof as an essential component are preferable from the viewpoint of being suitable for homopolymerization or copolymerization. In the case of acrylic acid, an acrylic acid aqueous solution containing 60% by mass or more of acrylic acid anhydride or acrylic acid may be used. The acrylic acid aqueous solution may be an alkali metal acrylate aqueous solution such as a sodium acrylate aqueous solution or a potassium acrylate aqueous solution obtained by neutralizing part or all of the acid.

  In the monomer aqueous solution, in addition to the α-unsaturated carboxylic acid or a salt thereof, hydrophilic monomers such as maleic acid, acrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and the like can be copolymerized therewith. May be included. The content of the hydrophilic monomer in all monomers is preferably 0 to 30 mol% from the viewpoint of increasing the polymerization reaction rate and facilitating the control of the molecular weight.

  In addition, the monomer aqueous solution may contain a polymerization inhibitor, a crosslinking agent, and the like.

  The monomer concentration of the aqueous monomer solution is preferably 10 to 60% by mass and more preferably 20 to 50% by mass from the viewpoint of increasing productivity and facilitating control of reaction and temperature. preferable.

  The pH of the aqueous monomer solution is preferably 5 to 9 from the viewpoint of reactivity, and more preferably 6 to 7 from the viewpoint of performing an initiation reaction with high initiator efficiency.

  The temperature of the aqueous monomer solution is preferably 5 ° C. or higher from the viewpoint of handling as an aqueous solution, and is preferably 30 ° C. or lower from the viewpoint of suppressing polymerization of the monomer before starting the reaction. From these viewpoints, the temperature of the monomer aqueous solution is preferably 5 to 30 ° C. When maleic acid is copolymerized, when the maleate is used as an aqueous solution, the temperature of the maleate aqueous solution is preferably 50 to 90 ° C.

  An aqueous solution containing bisulfite (hereinafter referred to as “bisulfite aqueous solution”) is an aqueous solution of bisulfite such as sodium bisulfite, potassium bisulfite, magnesium bisulfite, and the like. Among these bisulfites, sodium bisulfite having a strong reducing action is preferable.

  In addition, the aqueous hydrogen sulfite solution may contain a polymerization inhibitor, a crosslinking agent, and the like.

  The concentration of the bisulfite aqueous solution is preferably 1 to 40% by mass, and more preferably 20 to 40% by mass from the viewpoint of productivity.

  The amount of bisulfite makes it easy to control the molecular weight suitable for the intended use, and suppresses the formation of a reaction adduct (hereinafter simply referred to as “reaction adduct”) between an initiator and a monomer or a salt thereof. Therefore, it is preferable to control to be 0.008 to 0.1 mol with respect to 1 mol of the monomer.

  The gas containing oxygen (hereinafter referred to as “oxygen-containing gas”) generally includes air, but may be pure oxygen gas or a gas obtained by diluting pure oxygen with an inert gas.

  The oxygen-containing gas may additionally contain gaseous raw material monomers and the like.

  The oxygen concentration of the oxygen-containing gas is preferably 10% by volume or more, more preferably 20% by volume or more from the viewpoint of reactivity with hydrogen sulfite.

  Examples of the oxygen-containing gas supply device include a compressor and a blower facility. From the viewpoint of stabilizing the reaction, it is preferable to supply the oxygen-containing gas while maintaining the gas pressure at a constant pressure and also maintaining the gas supply amount per unit time at a constant volume.

  Although a 1st reactor is not specifically limited, It is preferable to use a flow-type mixer from a viewpoint of carrying out gas-liquid mixing of monomer aqueous solution and hydrogen sulfite aqueous solution, and oxygen-containing gas. Examples of the flow mixer include a static mixer such as a static mixer or an orifice mixer; a jet nozzle such as an ejector; a pipe stirrer such as a line mixer. Among these flow-type mixers, it is preferable to use a static mixer from the viewpoint that high mixing performance can be exhibited even with a small amount of gas, and from the viewpoints of durability and maintainability of equipment. .

  As a method for introducing a reaction fluid comprising a monomer aqueous solution, a hydrogen sulfite aqueous solution and an oxygen-containing gas into the first reactor, for example, supply of the monomer aqueous solution to a monomer aqueous solution supply pipe for introducing the monomer aqueous solution into the first reactor. A method of supplying an aqueous solution of hydrogen sulfite from an aqueous hydrogen sulfite solution supply pipe connected to the piping and supplying an oxygen-containing gas from an oxygen-containing gas supply piping connected to the aqueous monomer solution supply pipe, the aqueous monomer solution, and the bisulfite salt Examples include a method of directly introducing each of the aqueous solution and the oxygen-containing gas into the first reactor individually. Among these methods, the former method, that is, a method of preliminarily mixing the aqueous solution and the gas in the first stage of the first reactor is preferable from the viewpoint that the dispersibility of gas and liquid can be improved. When two or more types of monomer aqueous solutions are used, the monomer aqueous solutions may be mixed and introduced into the first reactor, or each monomer aqueous solution may be individually introduced into the first reactor. .

  By the way, the gas-liquid mixed state in the first reactor is an important factor determining the reactivity of the first polymerization reaction. In order to stably generate free radicals by the reaction of hydrogen sulfite and oxygen, it is preferable to create a dispersed flow state in which fine bubbles are dispersed in the liquid and to improve the contact efficiency of the gas and liquid.

  When a static mixer is used as the first reactor, the flow rate of the mixture of the monomer aqueous solution and the hydrogen sulfite aqueous solution in the static mixer is in a dispersed flow state within a range that does not result in an unstable fluid state that pulsates. From the viewpoint of forming the thickness, it is preferably 0.5 m / s or more, and more preferably 1.0 m / s or more. From the same viewpoint, the flow rate of the oxygen-containing gas in the static mixer is preferably 1.0 m / s or more, and more preferably 3.0 m / s or more. These flow rates can be adjusted, for example, by the minimum cross-sectional area of the portion through which the reaction fluid passes in the static mixer.

  When a jet nozzle is used as the first reactor, the flow rate of the mixed solution of the monomer aqueous solution and the hydrogen sulfite aqueous solution in the jet nozzle is preferably 1.0 m / s or more from the viewpoint of forming a dispersed flow state. More preferably, it is set to 0.0 m / s or more. From the same viewpoint, the flow rate of the oxygen-containing gas in the jet nozzle is preferably 5 m / s or more, and more preferably 10 m / s or more. These flow rates can be adjusted by, for example, the minimum cross-sectional area of the portion through which the reaction fluid passes in the jet nozzle.

  When a pipe stirrer is used as the first reactor, it is preferable to control the rotational speed of the stirring blade and the driving force thereof so that the bubble diameter is 1000 μm or less.

  Ratio of the volume of the oxygen-containing gas in the standard state (273 K, 101.3 kPa) to the total volume of the monomer aqueous solution and the bisulfite aqueous solution introduced into the first reactor (value obtained by dividing the volume of the oxygen-containing gas by the volume of the mixed solution) (Hereinafter referred to as “liquid-gas ratio”) depends on the type of the first reactor, but usually produces a dispersed flow state and increases the solubility of the oxygen-containing gas in the aqueous monomer solution and the aqueous bisulfite solution. Further, from the viewpoint of performing a polymerization reaction with high initiator efficiency, it is preferably controlled to be 1 or more, and more preferably 4 or more. On the other hand, the liquid gas ratio is preferably controlled to be 300 or less from the viewpoint of reducing the pressure loss in the first reactor and stabilizing the flow state and stabilizing the molecular weight of the resulting polymer. It is more preferable to control to be as follows. From these viewpoints, the liquid gas ratio is preferably controlled to be 1 to 300, and more preferably 4 to 200.

  The residence time of the reaction fluid in the first reactor is preferably 0.05 seconds or more, more preferably 0.1 seconds or more from the viewpoint of performing a start reaction with high start efficiency. On the other hand, even in the case of a very fast redox initiation reaction, it is preferably 30 seconds or less, preferably 10 seconds or less, from the viewpoint of suppressing temperature rise due to polymerization heat and pressure loss of the first reactor. It is more preferable. From these viewpoints, the residence time is preferably 0.05 to 30 seconds, and more preferably 0.1 to 10 seconds.

  The reaction temperature in the first polymerization reaction step is preferably set to 80 ° C. or less from the viewpoint of suppressing the molecular chain branching and hue deterioration of the polymer and suppressing the formation of the reaction adduct. More preferably. On the other hand, the reaction temperature is preferably 5 ° C. or higher from the viewpoint of handling the resulting reaction fluid as a polymer aqueous solution. From these viewpoints, the reaction temperature is preferably 5 to 80 ° C, and more preferably 5 to 60 ° C. Examples of the method for controlling the reaction temperature include a method for selecting polymerization reaction conditions in the first reactor, a method for controlling the polymerization rate, a method for removing polymerization heat by a temperature control mechanism, and the like.

  Examples of the temperature control mechanism include general heat exchangers such as a double tube heat exchanger, a multi-tube heat exchanger, and a spiral heat exchanger.

  The polymerization rate in the first polymerization reaction step is preferably controlled to be 30% or more and 35% or more from the viewpoint of performing an initiation reaction with high initiation efficiency and suppressing the amount of reaction adduct produced. More preferably, the control is performed. On the other hand, the polymerization rate is preferably controlled to be 90% or less from the viewpoint of reducing the apparatus cost and the amount of oxygen-containing gas used and obtaining a polymer having a constant quality, and is 80% or less. It is more preferable to control so that it becomes. From these viewpoints, the polymerization rate is preferably controlled to be 30 to 90%, and is preferably controlled to be 35 to 80%. Examples of factors that control the polymerization rate include residence time in the first reactor, reaction temperature, liquid gas ratio, and amount of bisulfite.

  The viscosity of the reaction fluid obtained in the first polymerization reaction step creates a dispersed flow state in which fine bubbles are dispersed in the liquid in order to stably generate free radicals by the reaction between bisulfite and oxygen. From the viewpoint of increasing the contact efficiency, it is preferably controlled to be 700 mPa · s or less at 20 ° C., and more preferably 400 mPa · s or less. Within such a viscosity range, the absorption efficiency of the oxygen-containing gas into the mixed solution becomes high, the molecular weight can be controlled even with a small amount of initiator, and the formation of reaction adducts can be suppressed. The control of the viscosity of the reaction fluid obtained in the first polymerization reaction step is the control of the polymerization rate. Therefore, the factors controlling it are, for example, residence time in the first reactor, reaction temperature, liquid gas ratio, Examples include the amount of bisulfite.

  The reaction fluid in which the monomer from the first reactor is polymerized is a gas-liquid mixed fluid containing unreacted monomer, and is sent to the second polymerization reaction step via a pipe. In addition, before sending to a 2nd polymerization reaction process, you may make a reaction fluid pass through a heat exchanger, a storage tank, a gas-liquid separation apparatus, etc.

<Second polymerization reaction step>
In the second polymerization reaction step, the reaction fluid containing the unreacted monomer obtained in the first polymerization reaction step is introduced into the second reactor to further polymerize the unreacted monomer.

  Examples of the second reactor include a flow mixer installed in a pipe, a stirred tank reactor, a flow mixer installed in a loop pipe, a bubble column for contacting and mixing gas and liquid, and the like. Examples thereof include a gas-liquid reactor capable of performing a gas-liquid mixing operation.

  Examples of the flow mixer include a static mixer such as a static mixer and an orifice mixer; a jet nozzle such as an ejector; and a pipe stirrer such as a line mixer.

  Examples of the stirred tank reactor include a stirred tank that performs gas-liquid mixing by an impeller, a nozzle jet, a ventilation operation, and the like.

  In the second polymerization reaction step, it is preferable to supply a new oxygen-containing gas to the reaction fluid before being introduced into the second reactor within a range in which the pressure loss of the facility is allowed. Thereby, the polymerization rate can be increased by suppressing the decrease in the absorption rate of the oxygen-containing gas due to the increase in the viscosity of the reaction fluid.

  The oxygen-containing gas may additionally contain gaseous raw material monomers and the like.

  The oxygen concentration of the oxygen-containing gas is preferably 10% by volume or more, more preferably 15% by volume or more from the viewpoint of reactivity.

  As a method for supplying the oxygen-containing gas to the reaction fluid before being introduced into the second reactor, for example, an oxygen-containing gas is connected to a pipe through which the reaction fluid flows from an oxygen-containing gas supply pipe connected to the pipe. The method etc. which supply are mentioned.

  Examples of the oxygen-containing gas supply device include a compressor and a blower facility. From the viewpoint of stabilizing the reaction, it is preferable to supply the oxygen-containing gas while maintaining the gas pressure at a constant pressure and also maintaining the gas supply amount per unit time at a constant volume.

  The reaction temperature in this second polymerization reaction step is preferably 80 ° C. or less, and preferably 60 ° C. or less from the viewpoint of suppressing the molecular chain branching and hue deterioration of the polymer and suppressing the formation of the reaction adduct. More preferably. On the other hand, the reaction temperature is preferably 5 ° C. or higher from the viewpoint of handling the resulting reaction fluid as a polymer aqueous solution. From these viewpoints, the reaction temperature is preferably 5 to 80 ° C., more preferably 5 to 60 degrees. Examples of the method for controlling the reaction temperature include a method for selecting a polymerization reaction condition in the second reactor, a method for controlling a polymerization rate, a method for removing polymerization heat by a temperature control mechanism, and the like.

  Examples of the temperature control mechanism include general heat exchangers such as a double-tube heat exchanger, a multi-tube heat exchanger, and a spiral heat exchanger; a jacket and a coil attached to a stirring tank, and the like. .

  The reaction fluid in which the monomer from the second reactor is further polymerized is a gas-liquid mixed fluid, and is sent to a gas-liquid separation mechanism via a pipe.

  Examples of the gas-liquid separation mechanism include a cyclone, a falling film type gas-liquid separation tower, and a gas separation tank having an exhaust valve. A heat exchanger for condensing water vapor in the discharged gas may be installed in the gas discharge portion of the gas-liquid separation mechanism as necessary. In the case of a gas separation tank, it is preferable that a stirrer is attached in order to perform cooling or prevent the monomer concentration from locally increasing.

  In the second polymerization reaction step, it is preferable to continue the reaction until the polymerization rate reaches 95% or more from the viewpoint of improving the quality of the polymer to be produced.

<Product recovery>
The reaction fluid of the aqueous solution that has passed through the first and second polymerization reaction steps is recovered.

  The recovered reaction fluid containing a carboxylic acid polymer as a product is more preferably subjected to an aging operation for reducing unreacted monomers in a product receiving tank or the like from the viewpoint of further increasing the polymerization rate. The content of the unreacted monomer in the reaction fluid is preferably 1.0% by mass or less, and 0.5% by mass or less in a 40% by mass aqueous solution of the polymer from the viewpoint of improving quality and yield. It is more preferable that The content of the reaction adduct is preferably 2.0% by mass or less and 40% by mass or less in a 40% by mass aqueous solution of the polymer from the viewpoint of improving quality and yield. More preferred.

  The weight average molecular weight of the carboxylic acid polymer in the recovered reaction fluid is preferably 1000 to 100,000 from the viewpoint of enhancing dispersibility and adsorptivity, and the polymer is a builder for detergent, a dispersant, a scale inhibitor, etc. In the case of using for, it is preferably 2000-30000. Further, the dispersion index (Mw / Mn) obtained by dividing the weight average molecular weight by the number average molecular weight is preferably 7 or less, and more preferably 5 or less.

  The solid content of the recovered reaction fluid is preferably 20% by mass or more from the viewpoint of improving productivity.

  The recovered reaction fluid may be subjected to post-treatment such as solid content adjustment, pH adjustment, deodorization treatment, and decolorization treatment.

<Pressurization of reaction fluid>
In the method for producing a carboxylic acid polymer of the present embodiment, a gas-liquid two-phase flow reaction fluid containing an oxygen-containing gas flowing through a predetermined pipe portion is pressurized in the first and second polymerization reaction steps. In this way, since the reaction fluid flowing through the predetermined pipe portion is pressurized, the reaction fluid is closer to the bubble flow state than the slag flow state, thereby suppressing the vibration of the pipe portion.

  The piping portion that pressurizes the reaction fluid is a piping portion that communicates with at least an open tube end through which a gas-liquid two-phase flow reaction fluid containing a gas containing oxygen flows. The “pipe portion communicating with the opened tube end” is a tube portion that communicates with the opened tube end and the other tube end is coupled to a member such as a mixer or a heat exchanger. Note that the pressurization of the reaction fluid is preferably performed not only in the above-described pipe portion but also in other pipes, and is performed in all pipes through which the gas-liquid two-phase flow containing oxygen-containing gas flows. Is more preferable. In particular, when the reaction fluid is pressurized before the second polymerization reaction step, the dissolved concentration of oxygen in the reaction fluid increases, thereby promoting the polymerization reaction in the second polymerization reaction step.

  Examples of the method (pressurizing means) for pressurizing the reaction fluid include a method of adjusting the flow rate of the reaction fluid by providing a control valve at the pipe end of the pipe portion.

  The pressurized pressure of the reaction fluid is preferably 0.05 MPa or more, and more preferably 0.1 MPa or more.

  Since vibration of the piping is significant when the liquid gas ratio of the flowing reaction fluid is 0.1 to 100, the vibration suppressing effect is particularly remarkable in the range of the liquid gas ratio.

  Next, each of the apparatus structures 1-3 for implementing the manufacturing method of the carboxylic acid-type polymer of this embodiment is demonstrated.

(Device configuration 1)
FIG. 1 shows a polymerization reaction apparatus A according to apparatus configuration 1.

  The polymerization reaction apparatus A includes a first polymerization unit 10 and a second polymerization unit 20.

  The first polymerization unit 10 includes a first main body pipe 12 extending from a monomer aqueous solution supply source and having a first flow mixer (first reactor) 11 interposed therebetween. A metering pump (not shown) is interposed near the monomer aqueous solution supply source of the first main body pipe 12.

  A bisulfite supply pipe 13 extending from a bisulfite supply source (bisulfite aqueous solution supply source) is connected to the first main body pipe 12 upstream of the first flow mixer 11. In addition, a metering pump (not shown) is provided in the heavy supply pipe 13.

  A first air supply pipe 14 extending from a compressor (oxygen-containing gas supply source) is connected to the upstream side of the connection portion of the heavy metal supply pipe 13 in the first main body pipe 12.

  The 2nd superposition | polymerization part 20 is equipped with the 2nd main body piping 22 connected to the 1st main body piping 12, and the 2nd flow-type mixer (2nd reactor) 21 and the heat exchanger 23 were interposed in order. Yes. Note that the second flow mixer 21 may have a configuration in which a plurality of second flow mixers 21 are provided in series in terms of increasing the polymerization rate.

  A second air supply pipe 24 extending from the compressor is connected to the second main body pipe 22 upstream of the second flow mixer 21.

  A control valve 30 (pressurizing means) is provided at the pipe end of the second main body pipe 22, and a product receiving tank 40 is provided below the pipe end. In addition, a pressure gauge P is provided in the second main body piping 22 in the immediate vicinity of the upstream side of the control valve 30.

  The control valve 30 and the pressure gauge P are connected to a control unit (not shown), and pressurize so that the pressure of the reaction fluid flowing through the pipe portion on the downstream side of the heat exchanger 23 in the second main body pipe 22 becomes a predetermined pressure. It is the structure which performs control.

  In the first polymerization unit 10, the polymerization reaction apparatus A supplies the sodium hydrogen sulfite aqueous solution and the air from the first air supply pipe 14 to the first main body pipe 12 for supplying the monomer aqueous solution from the deuterium supply pipe 13, respectively. Then, the reaction fluids are allowed to flow through the first flow mixer 11 to advance the polymerization reaction of the monomers (first polymerization reaction step), and the reaction fluid containing unreacted monomers is continuously fed to the second polymerization unit 20. In the second polymerization section 20, air is supplied from the second air supply pipe 24 to the reaction fluid containing unreacted monomers that circulates through the second main body pipe 22, and these reaction fluids are mixed in the second circulation type mixing. The polymerization reaction of the unreacted monomer proceeds by flowing through the vessel 21 (second polymerization reaction step), and the reaction fluid flowing through the second flow mixer 21 is heated by the heat exchanger 23 with the polymerization heat. Continuously recovering a product receiving vessel 40 after removal.

  At this time, the pipe part on the upstream side and the pipe part on the downstream side of the first flow-type mixer 11 of the first main body pipe 12, and the upstream side of the second flow-type mixer 21 of the second main body pipe 22. In the piping part, the piping part between the second flow mixer 21 and the heat exchanger 23, and the entire piping part downstream of the heat exchanger 23, the gas-liquid two-phase flow containing the oxygen-containing gas is generated. The reaction fluid flows.

  In this polymerization reaction apparatus A, the reaction fluid is pressurized in all the pipes through which the gas-liquid two-phase reaction fluid containing the oxygen-containing gas flows.

(Device configuration 2)
FIG. 2 shows a polymerization reaction apparatus A according to apparatus configuration 2. 1 are denoted by the same reference numerals as those in FIG.

  The polymerization reaction apparatus A includes a first polymerization unit 10 and a second polymerization unit 20.

  The first polymerization unit 10 includes a first main body pipe 12 extending from a monomer aqueous solution supply source and having a first flow mixer (first reactor) 11 interposed therebetween. A metering pump (not shown) is interposed near the monomer aqueous solution supply source of the first main body pipe 12.

  A bisulfite supply pipe 13 extending from a bisulfite supply source (bisulfite aqueous solution supply source) is connected to the first main body pipe 12 upstream of the first flow mixer 11. In addition, a metering pump (not shown) is provided in the heavy supply pipe 13.

  A first air supply pipe 14 extending from a compressor (oxygen-containing gas supply source) is connected to the upstream side of the connection portion of the heavy metal supply pipe 13 in the first main body pipe 12. For example, a sintered glass or a perforated plate is preferably provided in the air supply unit in order to reduce the bubble diameter to 1000 μm or less and increase the contact efficiency of the gas and liquid.

  A control valve 30 (pressurizing means) is provided at the pipe end of the first main body pipe 12. Further, a pressure gauge P is provided in the first main body pipe 12 in the immediate vicinity of the upstream side of the control valve 30.

  The control valve 30 and the pressure gauge P are connected to a control unit (not shown) so that the pressure of the reaction fluid flowing through the pipe portion on the downstream side of the first flow mixer 11 in the first main body pipe 12 becomes a predetermined pressure. The pressure control is performed.

  The second polymerization section 20 includes a stirred tank reactor (second reactor) 25 to which the first main body pipe 12 is connected. The stirred tank reactor 25 includes a stirrer 25a and a temperature adjustment jacket 25b, and an exhaust port 25c is formed.

  A second air supply pipe 24 extending from the compressor is connected to the bottom of the stirred tank reactor 25.

  In the first polymerization unit 10, the polymerization reaction apparatus A supplies the sodium hydrogen sulfite aqueous solution and the air from the first air supply pipe 14 to the first main body pipe 12 for supplying the monomer aqueous solution from the deuterium supply pipe 13, respectively. Then, the reaction fluid containing the unreacted monomer is passed through the first polymerization mixer 11 by allowing the reaction fluid to flow through the first flow mixer 11 (first polymerization reaction step). In the second polymerization section 20, air is supplied from the second air supply pipe 24 to the reaction fluid containing the unreacted monomer recovered in the stirring tank reactor 25 in the second polymerization section 20, and the temperature adjustment jacket 25 b is used. The polymerization reaction of the unreacted monomer proceeds by adjusting the temperature and stirring with the stirrer 25a (second polymerization reaction step).

  At this time, a gas-liquid two-phase flow reaction fluid containing an oxygen-containing gas flows through the pipe portion on the upstream side and the pipe portion on the downstream side of the first flow mixer 11 of the first main body pipe 12.

  In the pipe portion of the first main body pipe 12 on the downstream side of the first flow-type mixer 11, the pipe portion communicates with the opened pipe end, but the reaction fluid is provided with a control valve 30. The flow rate is limited by the pressure.

(Device configuration 3)
FIG. 3 shows a polymerization reaction apparatus A according to apparatus configuration 3. 1 are denoted by the same reference numerals as those in FIG.

  The polymerization reaction apparatus A includes a first polymerization unit 10 and a second polymerization unit 20.

  The first polymerization unit 10 includes a first main body pipe 12 extending from a monomer aqueous solution supply source and having a first flow mixer (first reactor) 11 interposed therebetween. A metering pump (not shown) is interposed near the monomer aqueous solution supply source of the first main body pipe 12.

  A bisulfite supply pipe 13 extending from a bisulfite supply source (bisulfite aqueous solution supply source) is connected to the first main body pipe 12 upstream of the first flow mixer 11. In addition, a metering pump (not shown) is provided in the heavy supply pipe 13.

  A first air supply pipe 14 extending from a compressor (oxygen-containing gas supply source) is connected to the upstream side of the connection portion of the heavy metal supply pipe 13 in the first main body pipe 12.

  The second polymerization section 20 includes a loop-shaped pipe 26 in which a second flow mixer (second reactor) 21, a heat exchanger 23, a gas-liquid separator 27, and a circulation pump 28 are interposed in order, The first main body pipe 12 is connected between the second flow mixer 21 and the circulation pump 28 of the loop-shaped pipe 26.

  A second air supply pipe 24 extending from the compressor is connected between the connection portion of the first main body pipe 12 and the second flow mixer 21 in the loop pipe 26.

  A recovery pipe 29 extends from between the circulation pump 28 and the connection portion of the first main body pipe 12 in the loop-shaped pipe 26. A product receiving tank 40 is provided below the pipe end of the collection pipe 29.

  A control valve 30 (pressurizing means) is provided in the loop-shaped pipe 26 in the immediate vicinity of the upstream side of the gas-liquid separator 27. In addition, a pressure gauge P is provided in the loop-shaped pipe 26 in the immediate vicinity of the upstream side of the control valve 30.

  The control valve 30 and the pressure gauge P are connected to a control unit (not shown), and the pressure of the reaction fluid flowing through the pipe portion between the heat exchanger 23 and the gas-liquid separator 27 in the loop pipe 26 is a predetermined pressure. Thus, the pressurization control is performed.

  In the first polymerization unit 10, the polymerization reaction apparatus A supplies the sodium hydrogen sulfite aqueous solution and the air from the first air supply pipe 14 to the first main body pipe 12 for supplying the monomer aqueous solution from the deuterium supply pipe 13, respectively. Then, the reaction fluids are allowed to flow through the first flow mixer 11 to advance the polymerization reaction of the monomers (first polymerization reaction step), and the reaction fluid containing unreacted monomers is continuously fed to the second polymerization unit 20. Then, in the second polymerization section 20, air is newly supplied from the second air supply pipe 24 to the reaction fluid while circulating the looped pipe 26 to the reaction fluid by the circulation pump 28, and these reaction fluids are supplied. Is allowed to flow through the second flow mixer 21 to advance the polymerization reaction of the unreacted monomer (second polymerization reaction step), and the reaction flow flows through the second flow mixer 21. Is then cooled by the heat exchanger 23, and then gas-liquid is separated by the gas-liquid separator 27, and the reaction fluid having the same amount as that of the reaction fluid supplied from the first main body pipe 12 is recovered via the circulation pump 28. It is constituted so that it may flow out continuously from and may be collected in product receiving tank 40.

  The supply amount of the reaction fluid from the first polymerization unit 10 to the second polymerization unit 20, and hence the product recovery amount from the second polymerization unit 20, is the flow rate of the reaction fluid circulating through the looped pipe 26 from the viewpoint of productivity. It is preferable to set it as 3.3 mass% or more of this, On the other hand, it is preferable to set it as 50 mass% or less from a viewpoint of controlling molecular weight or raising a polymerization rate. From these viewpoints, the supply amount of the reaction fluid to the loop-like pipe 26 and the recovery amount of the reaction fluid from the loop-like pipe 26 are preferably 3.3 to 50% by mass. Further, the average residence time of the reaction fluid in the looped pipe 26 is preferably 1 minute or more from the viewpoint of increasing the polymerization rate, while it is preferably 120 minutes or less from the viewpoint of reducing productivity and equipment. preferable. From these viewpoints, the average residence time of the reaction fluid in the looped pipe 26 is preferably 1 to 120 minutes.

  At this time, the pipe portion on the upstream side of the first flow mixer 11 and the pipe portion on the downstream side of the first main body pipe 12, and the second on the upstream side of the second flow mixer 21 of the loop pipe 26. 1 Piping portion from the connection portion of the main body piping 12 to the second flow mixer 21, a piping portion between the second flow mixer 21 and the heat exchanger 23, and the heat exchanger 23 and the gas-liquid separator 27 The gas-liquid two-phase flow reaction fluid containing the oxygen-containing gas flows in the pipe portion between the two.

  In the pipe portion between the heat exchanger 23 and the gas-liquid separator 27 of the loop-like pipe 26, the pipe portion communicates with a pipe end opened in the gas-liquid separator 27, but the reaction fluid is controlled by a control valve. By providing 30, the flow rate is limited and the pressure is increased.

  Note that in the pipe portion from the downstream side of the gas-liquid separator 27 in the loop-shaped pipe 26 to the connection portion of the second air supply pipe 24, the gas-liquid separator 27 separates the oxygen-containing gas and the reaction fluid containing only liquid. Therefore, it does not become a big factor to vibrate the piping.

(Test evaluation equipment)
FIG. 4 shows the polymerization reactor A used for the test evaluation. 1 are denoted by the same reference numerals as those in FIG.

  The polymerization reaction apparatus A includes a first polymerization unit 10 and a second polymerization unit 20.

  The first polymerization section 10 extends from the monomer aqueous solution supply source, and the first flow mixer 11 (orifice plate type static mixer manufactured by Fujikin Co., Ltd., trade name: Dispersion, model: 125D, number of plates: 5 pairs -10 sheets)) is provided. The first main body pipe 12 is provided. A metering pump (not shown) is interposed near the monomer aqueous solution supply source of the first main body pipe 12.

  A bisulfite supply pipe 13 extending from a bisulfite supply source (bisulfite aqueous solution supply source) is connected to the first main body pipe 12 upstream of the first flow mixer 11. In addition, a metering pump (not shown) is provided in the heavy supply pipe 13.

  A first air supply pipe 14 extending from a compressor (oxygen-containing gas supply source) is connected to the upstream side of the connection portion of the heavy metal supply pipe 13 in the first main body pipe 12.

  A pressure gauge P is interposed downstream of the first flow mixer 11 in the first main body pipe 12.

The second overlapping portions 20, and a capacitor stirring tank 25 of 3m ³ 'having an agitator 25a and a heating jacket, a loop-shaped pipe 26 provided so as to connect its bottom and top, a. A recovery tube 29 extends from the agitation tank 25 ′.

In the loop-shaped pipe 26, in order from the bottom side of the stirring tank 25 ', a circulation pump 28, a second flow mixer 21 (a grid plate type static mixer manufactured by Fujikin Co., Ltd., trade name: Mixing-kun, Model: 100M type, the number of plates: 5 sets to 10 sheets)), and a spiral heat exchanger 23 having a heat transfer area of 145 m ² , and a control valve 30 at the connection to the upper part of the stirring tank 25 ′. Is provided. Further, a pressure gauge P is provided in the immediate vicinity of the upstream side of the control valve 30 of the loop-shaped pipe 26.

  A second air supply pipe 24 extending from the compressor is connected between the circulation pump 28 of the loop-shaped pipe 26 and the second flow mixer 21.

  A temperature sensor (not shown) is provided in the vicinity of the downstream side of the heat exchanger 23 in the loop-shaped pipe 26.

  The pressure gauge P and the control valve 30 are respectively connected to a control unit (not shown), and the pressure of the reaction fluid flowing through the pipe portion between the heat exchanger 23 and the stirring tank 25 ′ in the loop-like pipe 26 is a predetermined pressure. In this way, the control valve 30 is controlled. The temperature sensor is also connected to the control unit, and is configured to control the heat exchanger 23 so that the temperature of the reaction fluid flowing through the loop-shaped pipe 26 becomes the set temperature.

  The first main body pipe 12 of the first superposition unit 10 is connected between the circulation pump 28 in the loop-like pipe 26 of the second superposition unit 20 and the connection part of the second air supply pipe 24.

  In the first polymerization unit 10, the polymerization reaction apparatus A supplies the sodium hydrogen sulfite aqueous solution and the air from the first air supply pipe 14 to the first main body pipe 12 for supplying the monomer aqueous solution from the deuterium supply pipe 13, respectively. Then, the reaction fluids are allowed to flow through the first flow mixer 11 to advance the polymerization reaction of the monomers (first polymerization reaction step), and the reaction fluid containing unreacted monomers is continuously fed to the second polymerization unit 20. In the second polymerization section 20, while circulating the looped pipe 26 to the reaction fluid by the circulation pump 28, air is newly supplied to the reaction fluid as needed from the second air supply pipe 24, The reaction fluid is allowed to flow through the second flow mixer 21 to advance the polymerization reaction of the unreacted monomer (second polymerization reaction step), and the second flow mixer 21 is passed through. The reaction fluid was cooled by heat exchanger 23, and is configured to recover the agitating tank 25 '.

  At this time, the pipe portion on the upstream side of the first flow mixer 11 and the pipe portion on the downstream side of the first main body pipe 12, and the second on the upstream side of the second flow mixer 21 of the loop pipe 26. 1 Piping portion from the connecting portion of the main body pipe 12 to the second flow mixer 21, a pipe portion between the second flow mixer 21 and the heat exchanger 23, and a pipe downstream of the heat exchanger 23 A gas-liquid two-phase flow reaction fluid containing air flows through the entire piping of the portion.

  In the pipe portion on the downstream side of the heat exchanger 23 of the loop-like pipe 26, the pipe portion communicates with the pipe end opened in the stirring tank 25 ′, but the reaction fluid is provided with a control valve 30. Thus, the flow rate is limited and the pressure is increased.

  In this polymerization reaction apparatus A, the reaction fluid is pressurized in all the piping through which the gas-liquid two-phase flow reaction fluid containing air flows.

(Polymer polymerization)
Polymers were polymerized according to the following Examples 1 and 2 and Comparative Examples. Detailed conditions are also shown in Table 1.

<Example 1>
In the 1st superposition | polymerization part 10, 38 mass% sodium acrylate aqueous solution (20 degreeC, pH = 6.3, neutralization degree: 95 mol%) is 3684L / from the 1st main body piping 12 with respect to the 1st flow-type mixer 11. FIG. It is supplied at a flow rate of hr, a 35 mass% aqueous sodium hydrogen sulfite solution (3.0 mol% to acrylic acid) is supplied from the deuterium supply pipe 13 at a flow rate of 125 L / hr, and air is supplied from the first air supply pipe 14 to 38 Nm ^3. / Hr (liquid / gas ratio G / L = 10) was supplied, and these reaction fluids were circulated through the first flow mixer 11. The pressure of the reaction fluid exiting from the first flow mixer 11 was 0.4 MPa.

In the second polymerization unit 20, the reaction fluid supplied from the first polymerization unit 10 is stirred in the stirring tank 25 ′, and the circulation pump 28 is operated to circulate the loop-shaped pipe 26 in the reaction fluid. Was repeatedly circulated through the second flow mixer 21. At this time, the control valve 30 was controlled so that the pressure of the reaction fluid flowing through the pipe portion on the downstream side of the heat exchanger 23 of the loop-like pipe 26 was 0.15 MPa (valve opening 9%). In addition, with respect to the reaction fluid in the loop-shaped pipe 26, the air from the second air supply pipe 24 is 25 Nm ³ / hr (the liquid of the reaction fluid that circulates in the pipe portion downstream from the heat exchanger 23 of the loop-shaped pipe 26. The gas flow rate was G / L = 1.6). Furthermore, the heat exchanger 23 was controlled so that the temperature of the reaction fluid was 30 ° C. The flow rate of the reaction fluid in the loop-shaped pipe 26 was 40 m ³ / hr, and the residence time of the reaction fluid in the loop polymerization portion was 40 minutes.

<Example 2>
In the second polymerization section 20, the polymer was polymerized in the same manner as in Example 1 except that the air was not supplied from the second air supply pipe 24. It should be noted that the pressure of the reaction fluid exiting from the first flow mixer 11 is 0.4 MPa, and the liquid-gas ratio G / L of the reaction fluid flowing through the pipe portion downstream of the heat exchanger 23 of the loop pipe 26 is 0.5. The valve opening was 10%, and the flow rate of the reaction fluid in the loop-shaped pipe 26 was 56 m ³ / hr.

<Comparative example>
The polymer was polymerized in the same manner as in Example 1 except that the control valve 30 was not controlled and the downstream side of the second flow mixer 21 was an open system. Note that the pressure of the reaction fluid exiting from the first flow mixer 11 is 0.3 MPa, and the liquid-gas ratio G / L of the reaction fluid flowing through the pipe portion downstream of the heat exchanger 23 of the loop-like pipe 26 is 1.1. The valve opening was 100%, and the flow rate of the reaction fluid in the loop-shaped pipe 26 was 56 m ³ / hr.

(Test evaluation method)
In each of Examples 1 and 2 and the comparative example, vibrations in the vicinity of the connection portion of the first main body pipe 12 with the loop-shaped pipe 26 and in the vicinity of the heat exchanger 23 of the loop-shaped pipe 26 were measured. Further, the residual monomer amount and the polymerization rate were determined for the reaction fluid sampled at each of the outlet of the first polymerization part 10 and the outlet of the second polymerization part 20.

<Piping vibration>
The x direction, the y direction, and the z direction are determined for each point in the vicinity of the connection portion of the first main body pipe 12 with the looped pipe 26 and in the vicinity of the heat exchanger 23 of the looped pipe 26. The amplitude value of the vibration in each direction was measured.

<Residual monomer amount>
For each reaction fluid, HPLC (high performance liquid chromatography) was used to determine the concentration of the residual monomer amount in the reaction fluid using a calibration curve of unreacted monomers of known concentration.

  The HPLC measurement conditions were as follows.

Column: manufactured by Tosoh Corporation, trade name: TSK-GEL ODS-80TS
Mobile phase: 0.02 mol / L Aqueous solution adjusted to pH 2.5 by adding phosphoric acid to potassium dihydrogen phosphate Detector: UV detector (wavelength: 210 nm)
Column temperature: 30 ° C
Flow rate: 1.0 mL / min
Sample: Ion exchange water was added to a polymer aqueous solution containing a solid content of 0.8 g, and 10 μL was fractionated from a column prepared to a total liquid volume of 200 mL.

<Polymerization rate>
For each reaction fluid, the polymerization rate was calculated from the amount of unreacted monomer before and after the reaction and the amount of monomer converted to the reaction adduct based on the following equation. The amount of monomer converted to the reaction adduct was determined by HPLC (high performance liquid chromatography).
(Polymerization rate)
= [(Amount of unreacted monomer before reaction)-(Amount of unreacted monomer after reaction)-(Amount of monomer converted to reaction adduct)] / [Amount of unreacted monomer before reaction] x 100
(Test evaluation results)
The test results are shown in Table 2.

<Piping vibration>
According to Table 2, in the vicinity of the connection portion between the first main body pipe 12 and the loop-shaped pipe 26, the pressure of the reaction fluid is 0.4 MPa higher than that of the comparative example in which the pressure of the reaction fluid is 0.3 MPa. It can be seen that in Examples 1 and 2, the amplitude values of vibrations are smaller in any of the x, y, and z directions.

  Further, in the vicinity of the heat exchanger 23 of the loop-shaped pipe 26, the pipe end of the pipe portion on the downstream side of the heat exchanger 23 of the loop-shaped pipe 26 is set as an open system, and the reaction fluid flowing therethrough is not pressurized. As compared with the comparative example, a control valve 30 is provided at the pipe end portion of the pipe portion on the downstream side of the heat exchanger 23 of the loop-like pipe 26, and control for pressurizing the reaction fluid flowing therethrough to a pressure of 0.15 MPa is performed. It can be seen that the amplitudes of the vibrations in the performed Examples 1 and 2 are smaller in any of the x direction, the y direction, and the z direction.

<Residual monomer amount and polymerization rate>
Compared to the comparative example in which the pipe end of the pipe portion on the downstream side of the heat exchanger 23 of the loop-shaped pipe 26 is an open system and the reaction fluid flowing therethrough is not pressurized, the heat exchanger of the loop-shaped pipe 26 In the second polymerization, Examples 1 and 2 in which a control valve 30 is provided at the pipe end portion of the pipe portion downstream of 23 and control is performed to pressurize the reaction fluid flowing therethrough to a pressure of 0.15 MPa. It can be seen that the amount of residual monomer contained in the reaction fluid finally obtained in part 20 is small and the polymerization rate is high.

  Moreover, the Example 1 which supplied air further in the 2nd superposition | polymerization part 20 finally was obtained in the 2nd superposition | polymerization part 20 rather than the Example 2 which did not supply air in the 2nd superposition | polymerization part 20. It can be seen that the amount of residual monomer contained in the reaction fluid is small and the polymerization rate is high.

  The present invention is useful for a method for producing a carboxylic acid polymer and a polymer production apparatus used therefor.

1 is a schematic view showing a polymerization reaction apparatus of apparatus configuration 1. FIG. It is the schematic which shows the polymerization reaction apparatus of the apparatus structure 2. FIG. It is the schematic which shows the polymerization reaction apparatus of the apparatus structure 3. FIG. It is the schematic which shows the polymerization reaction apparatus used in the Example.

Explanation of symbols

A Polymerization reaction apparatus 10 First polymerization section 11 First flow mixer 20 Second polymerization section 21 Second flow mixer 25 Stirred tank reactor 26 Loop pipe 30 Control valve (pressurizing means)

Claims (8)

Carboxylic acid heavy polymer which introduces a reaction fluid comprising an aqueous solution of a monomer containing α-unsaturated carboxylic acid or a salt thereof, an aqueous solution containing hydrogen sulfite, and a gas containing oxygen into the polymerization reactor to polymerize the monomer. A manufacturing method of coalescence,
Production of a carboxylic acid-based polymer that pressurizes a reaction fluid that circulates at least in a pipe portion that leads to an open pipe end through which a gas-liquid two-phase flow reaction fluid containing an oxygen-containing gas flows Method. (A) a first polymerization reaction step of introducing a reaction fluid into the first reactor to polymerize monomers;
(B) a second polymerization reaction step obtained by introducing the reaction fluid containing the unreacted monomer obtained in the first polymerization reaction step into the second reactor to further polymerize the unreacted monomer;
A process for producing a carboxylic acid polymer according to claim 1, comprising:   The method for producing a carboxylic acid polymer according to claim 1, wherein the reaction fluid flowing through the pipe portion is pressurized to 0.05 MPa or more.   The method for producing a carboxylic acid polymer according to claim 2, wherein in the second polymerization reaction step, a gas containing oxygen is newly supplied to the reaction fluid before being introduced into the second reactor. The second reactor of the second polymerization reaction step, the flow through type mixer which is interposed in the pipe, stirred tank reactors, or consists of a flow through type mixer which is interposed in a loop piping The method for producing a carboxylic acid polymer according to claim 2. 6. The carboxylic acid-based weight according to claim 1, wherein pressurization of the reaction fluid in the pipe portion is performed by adjusting a flow rate of the reaction fluid with a valve provided at a pipe end of the pipe portion. Manufacturing method of coalescence. The method for producing a carboxylic acid polymer according to claim 2, wherein in the first polymerization reaction step, a liquid gas ratio in the first reactor is controlled to 5 to 200. a monomer aqueous solution source for supplying an aqueous solution of a monomer containing an α-unsaturated carboxylic acid or a salt thereof;
An aqueous bisulfite solution source for supplying an aqueous solution containing bisulfite;
An oxygen-containing gas supply source for supplying a gas containing oxygen;
A reaction fluid comprising a monomer aqueous solution from the monomer aqueous solution source, a hydrogen sulfite aqueous solution from the hydrogen sulfite aqueous solution source, and an oxygen-containing gas from the oxygen-containing gas supply source is supplied, and the reaction fluid is mixed. A polymerization reactor for polymerizing the monomer together with,
With
The reaction fluid flows in the gas-liquid two-phase flow including a gas containing oxygen, arranged on the pipe end portion of the pipe section through at least open tube end, pressurize the reaction fluid flowing in the tubing portions And a carboxylic acid polymer production apparatus further comprising a valve for adjusting the flow rate of the reaction fluid .

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