Blending pre-esterification equipment and method for polyester polyol production

Abstract

The invention provides blending pre-esterification equipment and a blending pre-esterification method for polyester polyol production. The equipment comprises a barrel, wherein the barrel is provided with a raw material axial inlet, a raw material and protective gas tangential inlet, a gas phase outlet and a product outlet. The method comprises the following steps: enabling one or a combination of more of polycarboxylic acid and derivatives thereof, one part of polyhydric alcohol and a catalyst to enter blending pre-esterification equipment through a raw material axial inlet, enabling the other part of polyhydric alcohol to enter the blending pre-esterification equipment through a raw material tangential inlet, and enabling protective gas to enter the blending pre-esterification equipment; the raw materials are mixed in the equipment and subjected to esterification or transesterification reaction to obtain a pre-esterification product or a pre-transesterification product. According to the present invention, the blending process and the pre-esterification process are completed in the same device, such that the material blending effect at the pre-esterification stage during the polyester polyol production process can be improved, and the device investment and the process energy consumption can be reduced.

Description

Technical Field

[0001] The invention relates to a blending pre-esterification device and a method for producing polyester polyols, belonging to the technical field of polyester polyol production. Background Art

[0002] Polyester polyols are usually made from organic dicarboxylic acids (or anhydrides, esters) and diols (or polyols) through esterification (or transesterification), polycondensation, etc. Polyester polyols are one of the main raw materials for biodegradable plastics, engineering plastics and other materials. They are widely used in food packaging, fibers, films and other fields, and have broad market prospects.

[0003] At present, the traditional polyester polyol production process is mostly intermittent production process. Although intermittent production is flexible and can easily switch between multiple brands, its product quality fluctuates greatly, and the mass transfer and heat transfer process is limited, the device utilization rate is low, and the energy loss caused by repeated temperature rise and fall is large. The continuous synthesis of polyester polyols has the advantages of stable product quality, high degree of automation, short reaction time, and low energy and labor costs for producing unit quality products.

[0004] CN102532500A discloses a method and a device for continuously synthesizing polyester polyols. In this method, the raw materials are first fluidized and then reacted, and a circulating pump is used to circulate the reaction liquid in the reactor, so that continuous production can be achieved. However, this technology uses a pump circulation method to enhance mixing, which has high energy consumption; in addition, the raw material fluidization process and the reaction process are carried out in different equipment, and the equipment investment is high.

[0005] CN107987265 discloses a continuous preparation method of polyester polyols. The method includes a continuous preparation process of polyester polyols in three reaction stages: esterification, flash evaporation, and polycondensation. Compared with the traditional intermittent process, the method reduces the proportion of raw material polyols in the reaction solution, reduces the loss of polyols, increases the reaction temperature, shortens the reaction time, and makes the reaction conditions and product quality more stable. However, the method does not optimize the raw material mixing stage, and the process still has room for improvement in continuous production.

[0006] CN102432846A discloses a two-stage continuous production polyester polyol reaction device. The technology adopts a two-stage reaction device, and the residence time is uniform and controllable, the degree of automation is high, and it has good heat transfer and mass transfer efficiency. CN102585191A discloses a tower reactor with higher integration. The technology designs a multi-stage bubbling tower reactor, through the esterification (or transesterification) reaction and polycondensation reaction of polycarboxylic acid (or polycarboxylic acid derivative) and polyol (or polyol derivative) in the presence of a catalyst, polyester polyol is prepared, the reaction raw materials overflow from top to bottom, the protective gas, the small molecule steam produced by the reaction and the vaporized polyol are converged step by step from bottom to top through the bubbling air pipe, and the system is discharged from the top of the reactor. However, there is a certain dead zone in the inner tray of the kettle of these two technologies, and the bubbling air pipe is not easy to clean, and it is necessary to rely on violent bubbling to achieve mass transfer enhancement and self-cleaning.

[0007] Therefore, developing a blending pre-esterification device and method for the production of polyester polyols is still one of the problems to be solved urgently in the art. Summary of the invention

[0008] In order to solve the above technical problems, the purpose of the present invention is to provide a blending pre-esterification device and method for the production of polyester polyols. The technical solution of the present invention enables the blending process and the pre-esterification process to be completed in the same device, which can improve the material blending effect in the pre-esterification stage in the production process of polyester polyols and reduce equipment investment and process energy consumption.

[0009] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a blending pre-esterification equipment for the production of polyester polyols, the equipment comprising: a cylinder, the cylinder is provided with an axial inlet for raw materials, a tangential inlet for raw materials and protective gas, a gas phase outlet, and a product outlet; the tangential inlet for raw materials and protective gas is arranged on the side wall of the cylinder and is tangent to the side wall of the cylinder; the tangential inlet for raw materials and protective gas has an outer tube and an inner tube, the inner tube serves as the tangential inlet for protective gas, and the annular area between the outer tube and the inner tube serves as the tangential inlet for raw materials.

[0010] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, the barrel is a cylindrical barrel.

[0011] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, cylinder covers are respectively provided at the upper end and the lower end of the cylinder.

[0012] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, the raw material axial inlet is arranged at the bottom of the cylinder; and the gas phase outlet is arranged at the top of the cylinder.

[0013] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, the product outlet is arranged on the side wall of the cylinder and is located above the tangential inlet of the raw material and the protective gas.

[0014] In the above-mentioned blending pre-esterification equipment for producing polyester polyols, preferably, the number of the raw material and protective gas tangential inlets is multiple, and the multiple raw material and protective gas tangential inlets are evenly distributed on the side wall of the cylinder along the circumferential direction. More preferably, the number of the raw material and protective gas tangential inlets is 3 to 8.

[0015] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, the tangential inlet of the raw material and the protective gas is located in the same plane as the cross section of the cylinder or has a certain inclination angle with the plane where the cross section of the cylinder is located. More preferably, the tangential inlet of the raw material and the protective gas is arranged tangentially and obliquely upward on the side wall of the cylinder along the feeding and gas inlet directions, and the angle with the horizontal direction of the cross section of the cylinder is 15 to 85°.

[0016] In the above-mentioned blending pre-esterification equipment for the production of polyester polyols, preferably, the diameter ratio of the outer tube and the inner tube of the tangential inlet of the raw material and the protective gas is (1.5-10):1.

[0017] According to a specific embodiment of the present invention, preferably, the above-mentioned blending pre-esterification equipment for the production of polyester polyols further comprises: a raw material axial feed distributor, the raw material axial feed distributor comprises a distribution plate and a plurality of distribution pipes distributed on the distribution plate, the distribution plate is mounted on the inner wall of the cylinder, and the plurality of distribution pipes are parallel to the axial direction of the cylinder. More preferably, the raw material axial feed distributor is arranged below the tangential inlet of the raw material and the protective gas. More preferably, the plurality of distribution pipes can be fed independently.

[0018] According to a specific embodiment of the present invention, preferably, the above-mentioned blending pre-esterification equipment for the production of polyester polyols further comprises: a static mixer, which is installed on the inner wall of the cylinder. More preferably, the static mixer is arranged above the tangential inlet of the raw material and the protective gas and below the product outlet. The static mixer can be a conventional static mixer in the art, and the present invention does not specifically limit its structure.

[0019] In the above-mentioned co-blending pre-esterification equipment for producing polyester polyols, preferably, the raw material axial inlet is used to allow one or a combination of polycarboxylic acids and their derivatives, a part of polyols and catalysts to enter the co-blending pre-esterification equipment; the raw material tangential inlet is used to allow another part of polyols to enter the co-blending pre-esterification equipment. The derivatives of polycarboxylic acids may include anhydrides and / or esters formed by polycarboxylic acids.

[0020] A second aspect of the present invention provides a blending pre-esterification method for producing polyester polyols, the method using the above-mentioned blending pre-esterification equipment for producing polyester polyols, the method comprising the following steps:

[0021] One or a combination of polycarboxylic acids and their derivatives, a part of polyols and catalysts are allowed to enter the blending pre-esterification device through the raw material axial inlet, another part of polyols are allowed to enter the blending pre-esterification device through the raw material tangential inlet, and the protective gas is allowed to enter the blending pre-esterification device through the protective gas tangential inlet. The raw materials are mixed in the blending pre-esterification device and undergo esterification or ester exchange reaction. The generated by-products and gaseous substances in the reaction system are discharged through the gas phase outlet, and the generated pre-esterification products or pre-ester exchange products are discharged through the product outlet.

[0022] In the above method, the by-products generated mainly include water and / or tetrahydrofuran, etc., and the gas phase substances in the reaction system mainly include polyols and protective gas, etc.

[0023] According to a specific embodiment of the present invention, preferably, the method further comprises: after another part of the polyol enters the blending pre-esterification device through the raw material tangential inlet, it is mixed with the reaction raw material entering the blending pre-esterification device through the raw material axial inlet through a static mixer.

[0024] In the above method, preferably, the derivative of the polycarboxylic acid may include anhydrides and / or esters formed from the polycarboxylic acid.

[0025] In the present invention, polycarboxylic acids and their derivatives and polyols can all be raw materials for preparing polyester polyols conventionally used in the art. Among them, the derivatives of polycarboxylic acids can include anhydrides and / or esters formed by polycarboxylic acids, such as but not limited to terephthalic acid, succinic acid, dimethyl terephthalate, dimethyl succinate, succinic anhydride, etc., and the present invention does not specifically limit them.

[0026] In the above method, preferably, the mass ratio of the polyol entering the device through the raw material axial inlet to the polyol entering the device through the raw material tangential inlet is 1:(0.2-5).

[0027] In the above method, preferably, the molar ratio of the combination of one or more of the polycarboxylic acids and their derivatives to the polyol is 1:(0.6-4). It should be noted that the molar ratio is the molar ratio of the combination of one or more of the polycarboxylic acids and their derivatives to the total amount of the polyol added axially and tangentially.

[0028] In the above method, preferably, the catalyst is dispersed in the reactant or solvent and then enters the blending pre-esterification device through the raw material axial inlet. It can be understood by those skilled in the art that the reactant includes one or more combinations of polycarboxylic acids and their derivatives, and polyols. The solvent can be a conventional solvent in the art.

[0029] In the above method, preferably, the catalyst comprises one or a combination of catalysts selected from the group consisting of titanium, tin, antimony, zirconium and bismuth. More preferably, the catalyst comprises one or a combination of tetraisopropyl titanate, tetrabutyl titanate, titanium composite catalyst, dibutyltin dilaurate, stannous octoate and bismuth laurate.

[0030] In the above method, preferably, the amount of the catalyst used is 5 to 7000 ppm, more preferably 20 to 2000 ppm, based on the mass of one or a combination of several of the polycarboxylic acids and their derivatives.

[0031] In the above method, preferably, the protective gas includes nitrogen or the like.

[0032] In the above method, preferably, the temperature of the blending pre-esterification equipment is 100-260°C, more preferably 130-230°C, and further preferably 150-230°C.

[0033] In the above method, preferably, the pressure of the blending pre-esterification equipment is 10 to 101.325 kPa, more preferably 30 to 101.325 kPa, and further preferably 50 to 101.325 kPa.

[0034] According to a specific embodiment of the present invention, the raw materials are blended and pre-esterified or pre-esterified under the conditions of 100-260°C (preferably 130-230°C, more preferably 150-230°C) and 10-101.325kPa (preferably 30-101.325kPa, more preferably 50-101.325kPa) to obtain a pre-esterified product or a pre-esterified product. Preferably, the esterification rate or esterification rate of the pre-esterified product or the pre-esterified product is 80% or more. The pre-esterified product or the pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0035] The present invention provides a blending pre-esterification device and method for the production of polyester polyols. The technical solution of the present invention enables the blending process and the pre-esterification process to be completed in the same device, which can improve the material blending effect in the pre-esterification stage in the production process of polyester polyols, and can reduce equipment investment and process energy consumption. The present invention integrates the blending unit and the pre-esterification unit in the production process of polyester polyols, optimizes energy coupling, improves mass transfer and heat transfer efficiency, can realize continuous production of polyester polyols, and improves the preparation efficiency of pre-esterification products or pre-esterification products of polyester polyols.

[0036] The technical solution of the present invention has at least the following beneficial effects:

[0037] 1. The raw material blending process and the pre-esterification process are completed in the same equipment, and the continuous non-stirring operation is adopted, which reduces the equipment investment and operation time, reduces the process energy consumption, and improves the processing efficiency.

[0038] 2. The blending pre-esterification equipment adopts a combination of axial feeding and tangential feeding. The tangential inlet is located in the same plane as the cross section of the cylinder or has a certain inclination angle with the plane where the cross section of the cylinder is located, which is beneficial to improve the mixing effect of the materials and promote the esterification reaction.

[0039] 3. The tangential inlet of raw materials and protective gas has an outer tube and an inner tube. The inner tube serves as the tangential inlet of protective gas, and the outer tube serves as the tangential inlet of raw materials, which can enhance the mixing mass transfer process and regulate the pressure of the blending pre-esterification equipment.

[0040] 4. By adjusting the ratio of polycarboxylic acid or its derivatives to polyol in tangential feeding and axial feeding, the esterification rate can be easily regulated.

[0041] 5. The flow rate of the raw materials and protective gas near the tangential inlet of the blending pre-esterification equipment for the production of polyester polyols of the present invention is relatively large. It is preferred to set a local static mixer here to enhance the mixing effect while avoiding blockages caused by excessive accumulation of materials as much as possible.

[0042] In summary, the blending pre-esterification equipment and method for polyester polyol production provided by the present invention have the advantages of continuous production, no mechanical stirring, high mixing efficiency, low energy consumption, stable product quality, and easy application in large-scale production of polyester polyols. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure of a blending pre-esterification device for producing polyester polyols provided by some specific embodiments of the present invention.

[0044] Figure 2It is a schematic diagram of the structure of a blending pre-esterification device for producing polyester polyols provided in some other specific embodiments of the present invention.

[0045] Figure 3 yes Figure 2 AA cross-section diagram of the blending pre-esterification equipment used for polyester polyol production.

[0046] Description of Figure Numbers:

[0047] 1- cylinder; 2- axial inlet of raw materials; 3- tangential inlet of raw materials and protective gas; 4- gas phase outlet; 5- product outlet; 6- axial feed distributor of raw materials; 7- static mixer;

[0048] 301- tangential inlet for protective gas; 302- tangential inlet for raw materials;

[0049] 601-distribution plate; 602-distribution pipe. DETAILED DESCRIPTION

[0050] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0051] Example 1

[0052] This embodiment provides a blending pre-esterification device for the production of polyester polyols.

[0053] like Figure 1 As shown, the equipment includes: a cylinder 1, the cylinder 1 is provided with an axial inlet 2 for raw materials, a tangential inlet 3 for raw materials and protective gas, a gas phase outlet 4, a product outlet 5, and a raw material axial feed distributor 6; the axial inlet 2 for raw materials is arranged at the bottom of the cylinder 1; the tangential inlet 3 for raw materials and protective gas is arranged on the side wall of the cylinder 1 and is tangent to the side wall of the cylinder 1; the gas phase outlet 4 is arranged at the top of the cylinder 1; the product outlet 5 is arranged on the side wall of the cylinder 1; the product outlet 5 is arranged above the tangential inlet 3 for raw materials and protective gas; the tangential inlet 3 for raw materials and protective gas has an outer tube and an inner tube, the inner tube serves as the tangential inlet 301 for protective gas, and the annular area between the outer tube and the inner tube serves as the tangential inlet 302 for raw materials.

[0054] The cylinder body 1 is a cylindrical cylinder body. The upper end and the lower end of the cylinder body 1 are respectively provided with cylinder covers.

[0055] The number of the raw material and protective gas tangential inlets 3 is five, and the five raw material and protective gas tangential inlets 3 are evenly distributed on the side wall of the cylinder 1 along the circumferential direction.

[0056] The raw material and protective gas tangential inlet 3 is arranged tangentially and upwardly on the side wall of the cylinder 1 along the feeding and gas inlet directions, and the angle between the raw material and protective gas tangential inlet 3 and the horizontal direction of the cross section of the cylinder 1 is 45°.

[0057] The diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for the raw material and the protective gas is 5:1.

[0058] The raw material axial feed distributor 6 includes a distribution plate 601 and a plurality of distribution pipes 602 distributed on the distribution plate 601. The distribution plate 601 is installed on the inner wall of the cylinder 1, and the plurality of distribution pipes 602 are parallel to the axial direction of the cylinder 1. The raw material axial feed distributor 6 is arranged below the raw material and protective gas tangential inlet 3. The plurality of distribution pipes 602 can be fed independently.

[0059] This embodiment also provides a blending pre-esterification method for the production of polyester polyols, which adopts the above-mentioned blending pre-esterification equipment for the production of polyester polyols.

[0060] The method comprises the following steps:

[0061] Succinic acid, 1,4-butanediol and a catalyst are passed through a raw material axial inlet 2 and a raw material axial feed distributor 6 to enter a blending pre-esterification device; 1,4-butanediol is passed through a raw material tangential inlet 302 to enter the blending pre-esterification device; and nitrogen is passed through a protective gas tangential inlet 301 to enter the blending pre-esterification device; succinic acid, 1,4-butanediol and a catalyst are mixed in the blending pre-esterification device and an esterification reaction is carried out; the temperature of the blending pre-esterification device is 170° C. and the pressure is 101.325 kPa; the generated by-products and gaseous substances in the reaction system are discharged through a gas phase outlet 4; and the generated pre-esterification product is discharged through a product outlet 5.

[0062] The generated by-products mainly include water and / or tetrahydrofuran, and the gaseous substances in the reaction system mainly include 1,4-butanediol and nitrogen.

[0063] The mass ratio of 1,4-butanediol entering the device through the raw material axial inlet 2 to 1,4-butanediol entering the device through the raw material tangential inlet 302 is 1:1.

[0064] The molar ratio of succinic acid to the total amount of 1,4-butanediol is 1:1.2.

[0065] The feed amount of 1,4-butanediol at the five raw material tangential inlets 302 is the same. The feed amount of nitrogen at the five protective gas tangential inlets 301 is the same.

[0066] The catalyst used in this embodiment is tetrabutyl titanate, and its dosage is 5000ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification device through the raw material axial inlet 2.

[0067] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 78%. The esterification rate is calculated as follows: the molar amount of the polycarboxylic acid or its derivative participating in the reaction ÷ the molar amount of the polycarboxylic acid or its derivative that can react theoretically × 100%. The pre-esterified product can subsequently enter the esterification reactor for deep esterification.

[0068] Example 2

[0069] This embodiment provides a blending pre-esterification device for the production of polyester polyols.

[0070] like Figure 2 and Figure 3 As shown, the equipment includes: a cylinder 1, the cylinder 1 is provided with an axial inlet 2 for raw materials, a tangential inlet 3 for raw materials and protective gas, a gas phase outlet 4, a product outlet 5, a raw material axial feed distributor 6, and a static mixer 7; the axial inlet 2 for raw materials is arranged at the bottom of the cylinder 1; the tangential inlet 3 for raw materials and protective gas is arranged on the side wall of the cylinder 1 and is tangent to the side wall of the cylinder 1; the gas phase outlet 4 is arranged at the top of the cylinder 1; the product outlet 5 is arranged on the side wall of the cylinder 1; the product outlet 5 is arranged above the tangential inlet 3 for raw materials and protective gas; the tangential inlet 3 for raw materials and protective gas has an outer tube and an inner tube, the inner tube serves as the tangential inlet 301 for protective gas, and the annular area between the outer tube and the inner tube serves as the tangential inlet 302 for raw materials.

[0071] The cylinder body 1 is a cylindrical cylinder body. The upper end and the lower end of the cylinder body 1 are respectively provided with cylinder covers.

[0072] The number of the raw material and protective gas tangential inlets 3 is five, and the five raw material and protective gas tangential inlets 3 are evenly distributed on the side wall of the cylinder 1 along the circumferential direction.

[0073] The raw material and protective gas tangential inlet 3 is arranged tangentially and upwardly on the side wall of the cylinder 1 along the feeding and gas inlet directions, and the angle between the raw material and protective gas tangential inlet 3 and the horizontal direction of the cross section of the cylinder 1 is 60°.

[0074] The diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for the raw material and the protective gas is 3.5:1.

[0075] The raw material axial feed distributor 6 includes a distribution plate 601 and a plurality of distribution pipes 602 distributed on the distribution plate 601. The distribution plate 601 is installed on the inner wall of the cylinder 1, and the plurality of distribution pipes 602 are parallel to the axial direction of the cylinder 1. The raw material axial feed distributor 6 is arranged below the raw material and protective gas tangential inlet 3. The plurality of distribution pipes 602 can be fed independently.

[0076] The static mixer 7 is installed on the inner wall of the cylinder 1. The static mixer 7 is arranged above the tangential inlet 3 for raw materials and protective gas and below the product outlet 5. The static mixer 7 can be a conventional static mixer in the art, and the present invention does not specifically limit its structure.

[0077] This embodiment also provides a blending pre-esterification method for the production of polyester polyols, which adopts the above-mentioned blending pre-esterification equipment for the production of polyester polyols.

[0078] The method comprises the following steps:

[0079] Succinic acid, 1,4-butanediol and a catalyst are passed through a raw material axial inlet 2 and a raw material axial feed distributor 6 to enter a blending pre-esterification device; 1,4-butanediol is passed through a raw material tangential inlet 302 to enter the blending pre-esterification device, and is mixed with a reaction raw material that enters the blending pre-esterification device through the raw material axial inlet 2 via a static mixer 7; and nitrogen is passed through a protective gas tangential inlet 301 to enter the blending pre-esterification device; succinic acid, 1,4-butanediol and a catalyst are mixed in the blending pre-esterification device and an esterification reaction is carried out; the temperature of the blending pre-esterification device is 170° C. and the pressure is 101.325 kPa; the generated by-products and gaseous substances in the reaction system are discharged through a gas phase outlet 4; and the generated pre-esterification product is discharged through a product outlet 5.

[0080] The generated by-products mainly include water and / or tetrahydrofuran, and the gaseous substances in the reaction system mainly include 1,4-butanediol and nitrogen.

[0081] The mass ratio of 1,4-butanediol entering the device through the raw material axial inlet 2 to 1,4-butanediol entering the device through the raw material tangential inlet 302 is 1:1.

[0082] The molar ratio of succinic acid to the total amount of 1,4-butanediol is 1:1.2.

[0083] The feed amount of 1,4-butanediol at the five raw material tangential inlets 302 is the same. The feed amount of nitrogen at the five protective gas tangential inlets 301 is the same.

[0084] The catalyst used in this embodiment is tetrabutyl titanate, and its dosage is 5000ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification device through the raw material axial inlet 2.

[0085] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 85%. The esterification rate is calculated as follows: the molar amount of the polycarboxylic acid or its derivative participating in the reaction ÷ the molar amount of the polycarboxylic acid or its derivative that can react theoretically × 100%. The pre-esterified product can subsequently enter the esterification reactor for deep esterification.

[0086] Example 3

[0087] This embodiment provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 45°; the diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for raw materials and protective gas is 1.7:1.

[0088] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that the temperature of the blending pre-esterification equipment is 160°C and the pressure is 20 kPa.

[0089] The pre-esterified product was taken out at the product outlet 5, and after testing, it was found that the esterification rate of the pre-esterified product was 81%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0090] Example 4

[0091] This embodiment provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 30°; the diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for raw materials and protective gas is 10:1.

[0092] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that the temperature of the blending pre-esterification equipment is 200°C and the pressure is 90 kPa.

[0093] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 85%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0094] Example 5

[0095] This embodiment provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 80°; the diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for raw materials and protective gas is 8.5:1.

[0096] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that the temperature of the blending pre-esterification equipment is 210°C and the pressure is 60 kPa.

[0097] The pre-esterified product was taken out at the product outlet 5, and after testing, it was found that the esterification rate of the pre-esterified product was 87%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0098] Example 6

[0099] This embodiment provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 50°; the diameter ratio of the outer tube and the inner tube of the tangential inlet 3 for raw materials and protective gas is 6.8:1.

[0100] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that: the raw materials used are succinic acid, ethylene glycol and a catalyst, the mass ratio of ethylene glycol entering the equipment through the raw material axial inlet 2 to the ethylene glycol entering the equipment through the raw material tangential inlet 302 is 1:5, the molar ratio of succinic acid to the total amount of ethylene glycol is 1:1.2, the catalyst used is tetra-n-butyl titanate, the amount of which is 2000ppm of the mass of succinic acid, and the catalyst is dispersed in ethylene glycol and then enters the blending pre-esterification equipment through the raw material axial inlet 2; the temperature of the blending pre-esterification equipment is 150°C and the pressure is 30kPa.

[0101] The pre-esterified product was taken out at the product outlet 5, and after testing, it was found that the esterification rate of the pre-esterified product was 83%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0102] Example 7

[0103] This embodiment provides a blending pre-esterification device for producing polyester polyols. The device is basically the same as the device provided in Example 2, except that the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 15°.

[0104] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that: the mass ratio of 1,4-butanediol entering the equipment through the raw material axial inlet 2 to 1,4-butanediol entering the equipment through the raw material tangential inlet 302 is 1:0.2; the molar ratio of succinic acid to the total amount of 1,4-butanediol is 1:0.6; the catalyst used is tetra-n-butyl titanate, and its amount is 5ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification equipment through the raw material axial inlet 2; the temperature of the blending pre-esterification equipment is 260°C and the pressure is 10kPa.

[0105] The pre-esterified product was taken out at the product outlet 5, and after testing, it was found that the esterification rate of the pre-esterified product was 81%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0106] Example 8

[0107] This embodiment provides a blending pre-esterification device for producing polyester polyols. The device is basically the same as the device provided in Example 2, except that the angle between the tangential inlet 3 for raw materials and protective gas and the horizontal direction of the cross section of the cylinder 1 is 85°.

[0108] This embodiment also provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this embodiment. The method is basically the same as the method provided in Example 2, except that: the mass ratio of 1,4-butanediol entering the equipment through the raw material axial inlet 2 to 1,4-butanediol entering the equipment through the raw material tangential inlet 302 is 1:5; the molar ratio of succinic acid to the total amount of 1,4-butanediol is 1:4; the catalyst used is tetra-n-butyl titanate, and its amount is 7000ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification equipment through the raw material axial inlet 2; the temperature of the blending pre-esterification equipment is 100°C and the pressure is 101.325kPa.

[0109] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 70%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0110] Example 9

[0111] This embodiment provides a blending pre-esterification method for the production of polyester polyols. The method is carried out using the blending pre-esterification equipment provided in Example 2. The method is basically the same as the method provided in Example 2, except that: the catalyst used is tetra-n-butyl titanate, the amount of which is 20 ppm of the mass of succinic acid, and the catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification equipment through the raw material axial inlet 2; the temperature of the blending pre-esterification equipment is 130°C and the pressure is 101.325 kPa.

[0112] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 73%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0113] Example 10

[0114] This embodiment provides a blending pre-esterification method for producing polyester polyols. The method is carried out using the blending pre-esterification equipment provided in Example 2. The method is basically the same as the method provided in Example 2, except that the temperature of the blending pre-esterification equipment is 230°C and the pressure is 50 kPa.

[0115] The pre-esterified product is taken out at the product outlet 5, and after testing, it is found that the esterification rate of the pre-esterified product is 93%. The pre-esterified product can subsequently enter the esterification reaction kettle for deep esterification.

[0116] Comparative Example 1

[0117] This comparative example provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: no raw material tangential inlet is provided, only a raw material axial inlet and a protective gas tangential inlet are provided, and the diameter of the protective gas tangential inlet is the same as the inner tube diameter of the raw material and the protective gas tangential inlet 3 in Example 2; the number of the protective gas tangential inlets is 5, and the 5 protective gas tangential inlets are evenly distributed on the side wall of the cylinder along the circumferential direction; the protective gas tangential inlet is arranged tangentially and inclined upward on the side wall of the cylinder along the air intake direction, and the angle with the horizontal direction of the cross section of the cylinder is 60°; and no static mixer is provided.

[0118] This comparative example also provides a blending pre-esterification method for producing polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this comparative example.

[0119] The method comprises the following steps:

[0120] Succinic acid, 1,4-butanediol and a catalyst are passed through an axial raw material inlet and an axial raw material feed distributor to enter a blending pre-esterification device; and nitrogen is passed through five protective gas tangential inlets to enter the blending pre-esterification device; succinic acid, 1,4-butanediol and a catalyst are mixed in the blending pre-esterification device and an esterification reaction is carried out; the temperature of the blending pre-esterification device is 170° C. and the pressure is 101.325 kPa; the generated by-products and gaseous substances in the reaction system are discharged through a gas phase outlet, and the generated pre-esterification product is discharged through a product outlet.

[0121] The generated by-products mainly include water and / or tetrahydrofuran, and the gaseous substances in the reaction system mainly include 1,4-butanediol and nitrogen.

[0122] The molar ratio of succinic acid to 1,4-butanediol is 1:1.2.

[0123] The nitrogen intake rate at the five protective gas tangential inlets is the same.

[0124] The catalyst used is tetrabutyl titanate, and the amount used is 5000ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification equipment through the raw material axial inlet.

[0125] The pre-esterified product was taken out at the product outlet, and after testing, it was found that the esterification rate of the pre-esterified product was 71%.

[0126] Comparative Example 2

[0127] This comparative example provides a blending pre-esterification device for the production of polyester polyols. The device is basically the same as the device provided in Example 2, except that: instead of providing a raw material and protective gas tangential inlet 3 having an outer tube and an inner tube, three raw material tangential inlets and three protective gas tangential inlets are provided respectively, which are evenly distributed on the side wall of the cylinder along the circumferential direction, and the raw material tangential inlet and the protective gas tangential inlet are alternately arranged adjacent to each other; the diameter of the raw material tangential inlet and the diameter of the protective gas tangential inlet are the same as the inner tube diameter of the raw material and protective gas tangential inlet 3 in Example 2; the raw material tangential inlet and the protective gas tangential inlet are arranged tangentially and upwardly on the side wall of the cylinder along the feeding and gas inlet directions, respectively, and the angle with the horizontal direction of the cross section of the cylinder is 60°.

[0128] This comparative example also provides a blending pre-esterification method for producing polyester polyols. The method is carried out using the blending pre-esterification equipment provided in this comparative example.

[0129] The method comprises the following steps:

[0130] The succinic acid, 1,4-butanediol and catalyst are passed through the raw material axial inlet and the raw material axial feed distributor to enter the blending pre-esterification device; the 1,4-butanediol is passed through three raw material tangential inlets to enter the blending pre-esterification device, and is mixed with the reaction raw materials entering the blending pre-esterification device through the raw material axial inlet through a static mixer; and the nitrogen is passed through three protective gas tangential inlets to enter the blending pre-esterification device; the succinic acid, 1,4-butanediol and catalyst are mixed in the blending pre-esterification device and an esterification reaction is carried out. The temperature of the blending pre-esterification device is 170° C. and the pressure is 101.325 kPa. The generated by-products and gaseous substances in the reaction system are discharged through a gas phase outlet, and the generated pre-esterification product is discharged through a product outlet.

[0131] The generated by-products mainly include water and / or tetrahydrofuran, and the gaseous substances in the reaction system mainly include 1,4-butanediol and nitrogen.

[0132] The mass ratio of 1,4-butanediol entering the device through the axial inlet of the raw material to 1,4-butanediol entering the device through the tangential inlet of the raw material is 1:1.

[0133] The molar ratio of succinic acid to the total amount of 1,4-butanediol is 1:1.2.

[0134] The feed amount of 1,4-butanediol at the three raw material tangential inlets is the same. The feed amount of nitrogen at the three protective gas tangential inlets is the same.

[0135] The catalyst used is tetrabutyl titanate, and the amount used is 5000ppm of the mass of succinic acid. The catalyst is dispersed in 1,4-butanediol and then enters the blending pre-esterification equipment through the raw material axial inlet.

[0136] The pre-esterified product was taken out at the product outlet 5 and after testing, it was found that the esterification rate of the pre-esterified product was 81%.

Claims

1. A blending pre-esterification device for the production of polyester polyols, the device comprising: A cylinder body is provided with an axial inlet for raw materials, a tangential inlet for raw materials and protective gas, a gas phase outlet, and a product outlet; the tangential inlet for raw materials and protective gas is arranged on the side wall of the cylinder body and is tangential to the side wall of the cylinder body; the tangential inlet for raw materials and protective gas has an outer tube and an inner tube, the inner tube serves as the tangential inlet for protective gas, and the annular area between the outer tube and the inner tube serves as the tangential inlet for raw materials.

2. The blending pre-esterification equipment for polyester polyol production according to claim 1, wherein: The cylinder is a cylindrical cylinder; Preferably, the upper end and the lower end of the cylinder are respectively provided with cylinder covers; Preferably, the raw material axial inlet is arranged at the bottom of the cylinder; the gas phase outlet is arranged at the top of the cylinder; Preferably, the product outlet is arranged on the side wall of the cylinder and is located above the tangential inlet of the raw material and the protective gas.

3. The blending pre-esterification equipment for polyester polyol production according to claim 1, wherein: The number of the raw material and protective gas tangential inlets is multiple, and the multiple raw material and protective gas tangential inlets are evenly distributed on the side wall of the cylinder along the circumferential direction; Preferably, the tangential inlet of the raw material and the protective gas is located in the same plane as the cross section of the cylinder or is inclined at a certain angle to the plane where the cross section of the cylinder is located; Preferably, the raw material and protective gas tangential inlets are arranged tangentially and obliquely upward on the side wall of the cylinder along the feeding and gas inlet directions, and the angle between the inlet and the horizontal direction of the cross section of the cylinder is 15 to 85 degrees.

4. The blending pre-esterification equipment for polyester polyol production according to claim 1, wherein: The diameter ratio of the outer tube and the inner tube of the tangential inlet of the raw material and the protective gas is (1.5-10):

1.

5. The blending pre-esterification equipment for polyester polyol production according to claim 1, wherein: The device further comprises: a raw material axial feed distributor, the raw material axial feed distributor comprises a distribution plate and a plurality of distribution pipes distributed on the distribution plate, the distribution plate is mounted on the inner wall of the cylinder, and the plurality of distribution pipes are parallel to the axial direction of the cylinder; Preferably, the raw material axial feed distributor is arranged below the raw material and protective gas tangential inlet.

6. The blending pre-esterification equipment for polyester polyol production according to claim 1, wherein: The device further comprises: a static mixer, the static mixer being mounted on the inner wall of the cylinder; Preferably, the static mixer is arranged above the tangential inlet of the raw material and the protective gas and below the product outlet.

7. A blending pre-esterification method for producing polyester polyols, the method using the blending pre-esterification equipment for producing polyester polyols according to any one of claims 1 to 6, the method comprising the following steps: One or a combination of polycarboxylic acids and their derivatives, a part of polyols and catalysts are allowed to enter the blending pre-esterification device through the raw material axial inlet, another part of polyols are allowed to enter the blending pre-esterification device through the raw material tangential inlet, and the protective gas is allowed to enter the blending pre-esterification device through the protective gas tangential inlet. The raw materials are mixed in the blending pre-esterification device and undergo esterification or ester exchange reaction. The generated by-products and gaseous substances in the reaction system are discharged through the gas phase outlet, and the generated pre-esterification products or pre-ester exchange products are discharged through the product outlet.

8. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The mass ratio of the polyol entering the device through the raw material axial inlet to the polyol entering the device through the raw material tangential inlet is 1:(0.2-5).

9. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The molar ratio of the combination of one or more of the polycarboxylic acids and their derivatives to the polyol is 1:(0.6-4).

10. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The usage amount of the catalyst is 5 to 7000 ppm of the mass of one or a combination of several of the polycarboxylic acids and their derivatives.

11. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The protective gas includes nitrogen.

12. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The temperature of the blending pre-esterification equipment is 100-260°C.

13. The blending pre-esterification method for producing polyester polyols according to claim 7, wherein: The pressure of the blending pre-esterification equipment is 10 to 101.325 kPa.

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