Pipeline pressurizing and heating reaction device for unsaturated polyester synthesis

Abstract

The utility model discloses a pipeline pressurizing and heating reaction device for unsaturated polyester synthesis, which comprises a reaction kettle, a plate heat exchanger and a tubular heat exchanger, the plate heat exchanger is communicated with the reaction kettle and is connected with a steam inlet pipe, and a cold side is communicated with a material pipeline; the reaction kettle bottom valve is connected with the circulating pump which is connected with the tubular heat exchanger, and the tubular heat exchanger is connected with the reaction kettle through a circulating pipe; the shell-and-tube heat exchanger is connected with a conduction oil inlet-outlet pipe. The plate type heat exchanger and the tubular heat exchanger are matched with the pipeline outside the kettle to form a heating and pressurizing system outside the kettle, so that the effects of pressurizing and increasing the heat exchange area are achieved, and the reaction kettle does not need to be transformed. Dihydric alcohol is heated by a plate heat exchanger and then enters a reaction kettle, then liquid maleic anhydride and liquid phthalic anhydride are pumped into the reaction kettle, and unsaturated polyester is obtained after pressurization, heating and reaction are performed in a tubular heat exchanger and a pipeline for a period of time through circulation equipment outside the kettle, so that the heating time and the synthesis reaction time in the unsaturated polyester synthesis process can be shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production, in particular to a pipeline pressurized heating reaction device which can be used for synthesizing unsaturated polyester. Background Art

[0002] The unsaturated polyester synthesis process usually adopts the direct melt polycondensation method, that is, diols, dibasic acids or acid anhydrides and other reactants are put into the polycondensation kettle, and the temperature is raised to 190-220℃ under the protection of inert gas to react and generate polyester. Then put it into the dilution kettle containing diluent and inhibitor and mix it evenly to obtain viscous liquid unsaturated polyester resin.

[0003] With the continuous improvement of the unsaturated polyester synthesis process, the synthesis process using liquid anhydride instead of solid anhydride is widely used. The reaction using liquid anhydride is generally carried out under normal pressure. After the liquid anhydride (liquid maleic anhydride melting point 52.8°C, liquid phthalic anhydride melting point 131°C) is injected into the reactor and mixed with diol at room temperature, the liquid anhydride is prone to cooling and crystallization. After the reaction temperature rises, it needs to be dissolved again. This process cannot reasonably utilize the hot melting state of the liquid anhydride in the reaction process, and the reactors currently used in production are all normal pressure reactors. If a pressurized reaction is required, the equipment needs to be converted into a pressure reactor, which will involve many transformation costs and safety issues. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a pipeline pressurized heating reaction device for unsaturated polyester synthesis, which is simple in structure, realizes pressurization and heating through a pipeline outside the kettle, and plays a role of rapid heating and accelerated reaction.

[0005] In order to solve the above technical problems, the utility model adopts the following technical scheme: a pipeline pressurized heating reaction device for unsaturated polyester synthesis, comprising a reactor, the reactor is connected to a plate heat exchanger through a delivery pipe, and is connected to a shell and tube heat exchanger through a circulation pipe; the plate heat exchanger has a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet, the cold side outlet is connected to the delivery pipe, the delivery pipe is connected to the material inlet of the reactor, the hot side inlet is connected to a steam inlet pipe, and the hot side outlet is connected to a drain pipe; the shell and tube heat exchanger is connected to a heat transfer oil inlet pipe and a heat transfer oil outlet pipe, the feed port of the shell and tube heat exchanger is connected to a circulating rotor pump, the circulating rotor pump is connected to the discharge pipe of the reactor, and the discharge port of the shell and tube heat exchanger is connected to the reactor through a circulation pipe; the plate heat exchanger cooperates with the steam inlet pipe to form an external kettle heating structure, and the shell and tube heat exchanger cooperates with the circulating rotor pump and the circulation pipe to form an external kettle heating and pressurization structure.

[0006] Furthermore, a steam regulating valve is provided on the steam inlet pipe of the plate heat exchanger, and a steam trap is provided on the drain pipe.

[0007] Furthermore, a mass flow meter is provided on the pipeline connected to the cold side inlet of the plate heat exchanger, a temperature transmitter is provided on the delivery pipe connected to the cold side outlet, and a pressure transmitter is provided on the steam inlet pipe.

[0008] Furthermore, a temperature transmitter, a pressure transmitter and a pressure regulating valve are arranged on the circulation pipe, and the circulation pipe is led to below the liquid level of the reactor.

[0009] Furthermore, a discharge pipe is arranged at the bottom of the reaction kettle, and a bottom valve is arranged on the discharge pipe.

[0010] Furthermore, a stirring mechanism is provided on the reactor, the stirring mechanism is connected to a stirring motor, and the stirring motor is installed on the top of the reactor.

[0011] Preferably, the reactor is a normal pressure reactor made of stainless steel; the plate heat exchanger is a heat exchanger made of stainless steel with a temperature resistance of more than 200°C; and the shell and tube heat exchanger is a heat exchanger made of stainless steel with a temperature resistance of more than 250°C.

[0012] The utility model forms an external heating and pressurizing system by using a plate heat exchanger and a tube heat exchanger in conjunction with a pipeline outside the reactor, which plays a role in increasing pressure and heat exchange area, and does not require the reactor itself to be modified. The diol is heated by the plate heat exchanger and then enters the reactor, and then liquid maleic anhydride and liquid phthalic anhydride are injected, and then the reactor is circulated through the external circulation equipment, and the tube heat exchanger and pipeline are pressurized and heated, and the unsaturated polyester is obtained after a period of reaction, thereby reducing the heating time and synthesis reaction time in the synthesis process of the unsaturated polyester. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the utility model.

[0014] In the figure, 1 is a reactor, 11 is a stirring mechanism, 12 is a stirring motor, 13 is a discharge pipe, 2 is a plate heat exchanger, 21 is a hot side inlet, 22 is a cold side outlet, 23 is a hot side outlet, 24 is a cold side inlet, 3 is a delivery pipe, 31 is a temperature transmitter, 4 is a shell and tube heat exchanger, 41 is a heat transfer oil inlet pipe, 42 is a heat transfer oil outlet pipe, 5 is a circulating rotor pump, 6 is a circulating pipe, 61 is a temperature transmitter, 62 is a pressure transmitter, 7 is a steam inlet pipe, 71 is a pressure transmitter, 8 is a drain pipe, and 9 is a mass flow meter. DETAILED DESCRIPTION

[0015] In this embodiment, refer to Figure 1The pipeline pressurized heating reaction device for unsaturated polyester synthesis includes a reactor 1, which is connected to a plate heat exchanger 2 through a delivery pipe 3 and a shell-and-tube heat exchanger 4 through a circulation pipe 6; the plate heat exchanger 2 has a cold side inlet 24, a cold side outlet 22, a hot side inlet 21 and a hot side outlet 23, wherein the cold side outlet 22 is connected to the delivery pipe 3, the delivery pipe 3 is connected to the material inlet at the top of the reactor 1, the hot side inlet 21 is connected to a steam inlet pipe 7, and the hot side outlet 23 is connected to a drain pipe 8; the shell-and-tube heat exchanger 4 is connected to a heat transfer oil inlet pipe 41 and a heat transfer oil outlet pipe 42, which are used to input and output heat transfer oil so as to achieve heating and cooling. The feed port of the shell and tube heat exchanger 4 is connected to a circulating rotor pump 5, which is connected to the discharge pipe 13 of the reactor 1. The discharge port of the shell and tube heat exchanger 4 is connected to the reactor 1 from the top through the circulating pipe 6. The plate heat exchanger 2 cooperates with the steam inlet pipe 7 to form an external heating structure, and the shell and tube heat exchanger 4 cooperates with the circulating rotor pump 5 and the circulating pipe 6 to form an external heating and pressurizing structure.

[0016] A steam regulating valve (not shown) is provided on the steam inlet pipe 7 of the plate heat exchanger 2 , and a steam trap (not shown) is provided on the drain pipe 8 .

[0017] A mass flow meter 9 is provided on the pipeline connected to the cold side inlet 24 of the plate heat exchanger 2, and diol is input through the cold side inlet 24; a temperature transmitter 31 is provided on the delivery pipe 3 connected to the cold side outlet 22, and a pressure transmitter 71 is provided on the steam inlet pipe 7. A temperature transmitter 61, a pressure transmitter 62 and a pressure regulating valve (not shown) are provided on the circulation pipe 6, and the circulation pipe 6 is connected to the reactor 1 below the liquid level.

[0018] The discharge pipe 13 is arranged at the bottom of the reaction kettle 1 , and a bottom valve (not shown) is arranged on the discharge pipe 13 .

[0019] The reactor 1 is provided with a stirring mechanism 11 , the stirring mechanism 11 is connected to a stirring motor 12 , and the stirring motor 12 is installed on the top of the reactor 1 .

[0020] Reactor 1 is a normal pressure reactor made of stainless steel; plate heat exchanger 2 is a heat exchanger made of stainless steel with a temperature resistance of more than 200°C; tube heat exchanger 4 is a heat exchanger made of stainless steel with a temperature resistance of more than 250°C. Plate heat exchanger 2 is a heat exchanger made of 304 stainless steel with a temperature resistance of more than 200°C, with a heat exchange area of ​​16.5㎡. The circulating rotor pump is made of 304 stainless steel, with a flow rate of 18m 3 / h, material viscosity 100-1000CP, 1.6MPa, 250℃. The shell and tube heat exchanger 3 is a heat exchanger made of 304 stainless steel with a temperature resistance of more than 250℃, and the heat exchange area is 20㎡. The reactor 1 is a 6㎡ atmospheric pressure reactor made of 316 stainless steel. The material of each pipeline is 304 stainless steel DN50, with a pressure resistance of 1.6mPa.

[0021] The reactor 1 is provided with a heating coil and a heating jacket, and is provided with a temperature transmitter, a bimetallic temperature dial thermometer, a pressure transmitter and a bimetallic dial pressure gauge, a manhole and a manhole cover, and is equipped with a vertical condenser and a horizontal condenser.

[0022] The steps of the synthesis reaction process are as follows:

[0023] 1) introducing protective gas into the reactor 1;

[0024] 2) The diol is input into the plate heat exchanger 2 and heated to 120°C, and the plate heat exchanger 2 is passed through a steam heat source to raise the temperature to 180°C and the pressure to 1.0 MPa;

[0025] 3) The diol heated by the plate heat exchanger 2 is input into the reactor 1, and then the stirring mechanism 11 of the reactor 1 is turned on to inject liquid phthalic anhydride (liquid temperature 140°C), other powdered materials (if any) and liquid maleic anhydride (liquid temperature 70°C); because the reaction is extremely intense when injecting liquid maleic anhydride, it is necessary to control the head temperature not to exceed 105°C and the alcohol run-off. If the formula has a relatively large amount of liquid maleic anhydride, the liquid maleic anhydride can be added dropwise to avoid an overly intense reaction that is difficult to control.

[0026] 4) Turn on the external circulation mode, use the circulating rotor pump 5 to provide power to input the material into the tube-in-tube heat exchanger 4 through the discharge pipe 13 of the reactor 1 for heating, and control the pressure in the pipeline to 0.3 MPa, and then circulate it back to below the liquid level of the reactor 1 through the circulation pipe 6; heat transfer oil with a temperature of not less than 230° C. is introduced into the tube-in-tube heat exchanger 4 for heating;

[0027] 5) The reaction temperature is maintained at 200-220°C until the reaction is fully completed;

[0028] 6) The cooling process is continued, and the external circulation cooling is continued until the pot is put into the pot. During the cooling process, the heat transfer oil is changed to normal temperature cold oil to realize the external circulation cooling.

[0029] The specific data of the production results are shown in Tables 1 and 2 below:

[0030] Table 1: Conventional orthophthalic resin synthesis test data

[0031]

[0032] Table 2: Synthesis test data of terephthalate resin

[0033]

[0034] The test results in the table above show that the synthesis reaction time of the orthophthalic resin LY-191C is shortened by 2 hours, a shortening ratio of 14.81%; the synthesis reaction time of the para-phenylene resin LY-M8200 is shortened by 6.5 hours, a shortening ratio of 22.81%. It can significantly shorten the reaction time of the synthesis of orthophthalic and para-phenylene unsaturated polyester resins and improve production efficiency.

[0035] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A pipeline pressurized heating reaction device for unsaturated polyester synthesis, comprising a reaction kettle, characterized in that: The reactor is connected to a plate heat exchanger through a delivery pipe, and is connected to a shell-and-tube heat exchanger through a circulation pipe; the plate heat exchanger has a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet, the cold side outlet is connected to the delivery pipe, the delivery pipe is connected to the material inlet of the reactor, the hot side inlet is connected to a steam inlet pipe, and the hot side outlet is connected to a drain pipe; the shell-and-tube heat exchanger is connected to a heat transfer oil inlet pipe and a heat transfer oil outlet pipe, the feed port of the shell-and-tube heat exchanger is connected to a circulating rotor pump, the circulating rotor pump is connected to the discharge pipe of the reactor, and the discharge port of the shell-and-tube heat exchanger is connected to the reactor through a circulation pipe; the plate heat exchanger cooperates with the steam inlet pipe to form an external kettle heating structure, and the shell-and-tube heat exchanger cooperates with the circulating rotor pump and the circulation pipe to form an external kettle heating and pressurization structure.

2. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: A steam regulating valve is provided on the steam inlet pipe of the plate heat exchanger, and a steam trap is provided on the drain pipe.

3. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: A mass flow meter is provided on the pipeline connected to the cold side inlet of the plate heat exchanger, a temperature transmitter is provided on the delivery pipe connected to the cold side outlet, and a pressure transmitter is provided on the steam inlet pipe.

4. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: A temperature transmitter, a pressure transmitter and a pressure regulating valve are arranged on the circulation pipe, and the circulation pipe leads to below the liquid level of the reactor.

5. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: The discharge pipe is arranged at the bottom of the reaction kettle, and a bottom valve is arranged on the discharge pipe.

6. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: The reactor is provided with a stirring mechanism, the stirring mechanism is connected with a stirring motor, and the stirring motor is installed on the top of the reactor.

7. The pipeline pressurized heating reaction device for unsaturated polyester synthesis according to claim 1, characterized in that: The reaction kettle is a normal pressure kettle made of stainless steel; the plate heat exchanger is a heat exchanger made of stainless steel with a temperature resistance of more than 200°C; the shell and tube heat exchanger is a heat exchanger made of stainless steel with a temperature resistance of more than 250°C.

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