Disqualified bisphenol A cracking system

Abstract

The technical problem to be solved by the utility model is to provide the disqualified bisphenol A cracking system, disqualified bisphenol A is cracked into phenol and byproducts through a cracking agent, and the phenol generated after cracking is recycled again through a subsequent phenol recovery tower, so that the production and operation cost of bisphenol A can be effectively reduced, and the production efficiency is improved. The device comprises a cracking agent storage tank, a cracking reactor, a phenol recovery tower, a phenol recovery cooler and a phenol recovery storage tank, a feeding pipeline is arranged on the cracking reactor, the bottom of the cracking reactor is sequentially communicated with a cracking pump and a first circulating pipeline, and a discharging opening of the first circulating pipeline is communicated with the top of the cracking reactor; the side wall of the first circulating pipeline is communicated with a feed port of a phenol recovery tower through a discharge control valve matched with a pipeline, and a discharge port of the phenol recovery tower is sequentially communicated with a phenol recovery cooler and a phenol recovery storage tank.

Description

Technical Field

[0001] This utility model relates to the field of bisphenol A production, and in particular to a substandard bisphenol A cracking system. Background Technology

[0002] The production of bisphenol A (BPA) generates several byproducts, including impurities such as 2-4-bisphenol A (BPA) and immiscible bisphenol A (IMB). These substandard BPAs are produced by side reactions during BPA production, and if they are not removed from the system, they will seriously affect the quality of subsequent products. Separating these substandard BPAs during production and treating them as impurities only increases the cost of BPA production.

[0003] If substandard bisphenol A could be processed to extract the valuable products for reuse in bisphenol A production, production and operating costs could be effectively reduced. However, current extraction technology is not mature and the extraction effect is poor. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a pyrolysis system for substandard bisphenol A, which uses a pyrolysis agent to pyrolyze substandard bisphenol A into phenol and byproducts, and then uses a subsequent phenol recovery tower to recover and reuse the phenol produced after pyrolysis, which can effectively reduce the production and operating costs of bisphenol A.

[0005] This utility model is achieved through the following technical solution:

[0006] A substandard bisphenol A cracking system includes a cracking agent storage tank, a cracking reactor, a phenol recovery tower, a phenol recovery cooler, and a phenol recovery storage tank;

[0007] The pyrolysis reactor is equipped with a feed pipe, which has two branches. One branch connects to the outlet of the pyrolysis agent storage tank, and the other branch connects to the outlet of the unqualified bisphenol A solution in the production system.

[0008] The bottom of the pyrolysis reactor is connected in sequence to a pyrolysis pump and a first circulation pipe, and the outlet of the first circulation pipe is connected to the top of the pyrolysis reactor.

[0009] The first circulation pipeline is connected to the inlet of the phenol recovery tower via a discharge control valve on its side wall. The outlet of the phenol recovery tower is connected in sequence to the phenol recovery cooler and the phenol recovery storage tank.

[0010] Furthermore, the outer wall of the pyrolysis reactor is provided with a jacketed cavity, and steam is circulated into the jacketed cavity for heating.

[0011] Furthermore, the temperature inside the pyrolysis reactor is 185-195℃ and the pressure is 0.01-0.04 MPa.

[0012] Furthermore, the bottom of the phenol recovery tower is sequentially connected to a bottom pump, a second circulation pipeline, a heater, and the side wall of the phenol recovery tower.

[0013] Furthermore, the heater is equipped with a heat exchange coil, and steam is circulated through the heat exchange coil for heat tracing.

[0014] Furthermore, a delivery pump and a cracking agent flow meter are installed on the branch line between the outlet of the cracking agent storage tank and the feed pipe.

[0015] A method for preparing phenol by pyrolysis of substandard bisphenol A, comprising the following steps: (The method utilizes a substandard bisphenol A pyrolysis system to prepare phenol.)

[0016] S01. The cracking agent in the cracking agent storage tank and the unqualified bisphenol A solution produced by the production system are transported to the feed pipeline;

[0017] SO2, the cracking agent and the substandard bisphenol A are mixed in the feed pipe and then enter the cracking reactor together. The temperature of the cracking reactor is controlled at 185-195℃ and the pressure is controlled at 0.01-0.04Mpa.

[0018] S03. When the liquid level in the pyrolysis reactor reaches the required level, the pyrolysis pump is turned on for circulating pyrolysis. When the content of unqualified bisphenol A in the pyrolysis material is reduced to the required level after sampling and analysis, the discharge control valve of the pyrolysis reactor is turned on to transport the pyrolysis material to the phenol recovery tower.

[0019] S04. Heat the material in the phenol recovery tower and control the temperature of the material in the phenol recovery tower to be no lower than the boiling point of phenol, 181°C. The vaporized phenol is separated at the top of the phenol recovery tower and then cooled by the phenol recovery cooler. The cooled phenol solution is stored in the phenol recovery storage tank and used as a raw material for the production of bisphenol A.

[0020] Furthermore, in step S01, the pyrolysis agent and the substandard bisphenol A solution are fed into the feed pipe at a ratio of 4.45 to 5:1.

[0021] Furthermore, in step S04, the vaporized phenol is cooled by a cooling medium at 45°C when it passes through the phenol recovery cooler.

[0022] Furthermore, the pyrolysis agent is selected as dodecylbenzenesulfonic acid.

[0023] The beneficial effects achieved by this utility model compared with the prior art are as follows:

[0024] 1. The non-conforming bisphenol A cracking system described in this utility model cracks non-conforming bisphenol A into phenol and byproducts in the cracking reactor. The phenol produced after cracking is then recovered and reused through a subsequent phenol recovery tower, which can effectively reduce the production and operating costs of bisphenol A. Furthermore, the cracking recovery can effectively reduce the yield of byproducts and reduce the processing load of subsequent systems.

[0025] 2. The outer wall of the pyrolysis reactor is equipped with a jacketed cavity, in which steam is circulated for heating, thereby effectively controlling the temperature inside the pyrolysis reactor and ensuring pyrolysis efficiency.

[0026] 3. By using the bottom pump and heater of the recovery tower, the material in the phenol recovery tower can be circulated and heated, and the temperature of the material in the phenol recovery tower can be controlled to be no lower than the boiling point of phenol, 181℃, thereby accelerating the vaporization of phenol and improving the collection efficiency of phenol. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the non-conforming bisphenol A pyrolysis system described in this utility model;

[0028] In the diagram: 1. Cracking agent storage tank, 2. Cracking reactor, 3. Phenol recovery tower, 4. Phenol recovery cooler, 5. Phenol recovery storage tank, 6. Feed pipe, 7. Transfer pump, 8. Cracking pump, 9. First circulation pipe, 10. Discharge control valve, 11. Recovery tower bottom pump, 12. Second circulation pipe, 13. Heater. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] In the description of this utility model, it should be understood that the terms "front," "rear," "upper," "lower," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The utility model will be further described below with reference to the accompanying drawings and embodiments.

[0031] like Figure 1 As shown in the figure, this embodiment discloses a non-conforming bisphenol A cracking system, which mainly includes a cracking agent storage tank 1, a cracking reactor 2, a phenol recovery tower 3, a phenol recovery cooler 4, and a phenol recovery storage tank 5;

[0032] A feed pipe 6 is installed at the top of the pyrolysis reactor 2. Two branches are connected to the feed pipe 6: one branch connects to the outlet of the pyrolysis agent storage tank 1, and the other branch connects to the outlet of the substandard bisphenol A solution in the production system. A transfer pump 7 and a pyrolysis agent flow meter are also installed on the branch between the outlet of the pyrolysis agent storage tank 1 and the feed pipe 6. A substandard bisphenol A flow meter is also installed on the branch connecting to the outlet of the substandard bisphenol A solution in the production system. The pyrolysis ratio can be adjusted by controlling the flow rate.

[0033] Since bisphenol A has a melting point of 181℃, the pyrolysis reactor 2 is jacketed. A jacket cavity is installed on the outer wall of the pyrolysis reactor 2, and 2.0 MPa steam is circulated in the jacket cavity for heating to prevent material condensation inside the pyrolysis reactor 2. Temperature points, level gauges, and pressure points are installed on the pyrolysis reactor 2 to monitor the equipment's operating status. At the bottom of the pyrolysis reactor 2, a pyrolysis pump 8 and a first circulation pipe 9 are connected in sequence. The outlet of the first circulation pipe is connected to the top of the pyrolysis reactor 2. The side wall of the first circulation pipe 9 is connected to the inlet of the phenol recovery tower 3 via a discharge control valve 10.

[0034] At the bottom of the phenol recovery tower 3, a bottom pump 11, a second circulation pipe 12, a heater 13, and the side wall of the phenol recovery tower 3 are connected in sequence. A heat exchange coil is installed inside the heater, through which steam is circulated for heating. Under the action of the bottom pump 11, the material inside the phenol recovery tower 3 circulates through the heater for heating, thereby vaporizing and evaporating the phenol. The outlet at the top of the phenol recovery tower 3 is connected in sequence to a phenol recovery cooler 4 and a phenol recovery storage tank 5, thereby cooling and recovering the vaporized phenol.

[0035] Based on the aforementioned substandard bisphenol A pyrolysis system, this embodiment also discloses a method for preparing phenol by pyrolysis of qualified bisphenol A, comprising the following steps:

[0036] S01. The pyrolysis agent in the pyrolysis agent storage tank 1 and the unqualified bisphenol A solution produced by the production system are transported to the feed pipe 6 for mixing. The pyrolysis agent and the unqualified bisphenol A solution are added in a ratio of 4.45:1. The pyrolysis rate of unqualified bisphenol A can also be controlled by controlling the addition ratio.

[0037] In this embodiment, dodecylbenzenesulfonic acid is selected as the pyrolysis agent;

[0038] SO2, the cracking agent and the unqualified bisphenol A are mixed in the feed pipe 6 and then enter the cracking reactor 2 together. Since the melting point of bisphenol A is 181℃, the temperature of the cracking reactor 2 is controlled at 185-195℃ and the internal pressure is adjusted to the range of 0.01-0.04Mpa.

[0039] S03. When the liquid level in the cracking reactor 2 reaches the required level, the cracking pump is turned on to allow the material to circulate through the first circulation channel for cracking. The cracking agent dodecylbenzenesulfonic acid cracks the unqualified bisphenol A impurities into phenol and by-products. When the unqualified bisphenol A content in the cracked material is reduced to the required content after sampling and analysis, the discharge control valve of the cracking reactor 2 is turned on to transport the cracked material to the phenol recovery tower 3.

[0040] S04. Start the bottom pump of the recovery tower to circulate the material into the heater, thereby heating the material in the phenol recovery tower 3. Control the temperature of the material in the phenol recovery tower 3 to be no lower than the boiling point of phenol, 181℃. The vaporized phenol is separated at the top of the phenol recovery tower 3 and then cooled by the phenol recovery cooler 4. The phenol recovery cooler 4 uses a 45℃ cooling medium to prevent the phenol from crystallizing and clogging the cooler due to low temperature. The cooled phenol solution is stored in the phenol recovery storage tank 5 and used as a raw material for the production of bisphenol A.

[0041] The non-conforming bisphenol A cracking system described in this invention cracks non-conforming bisphenol A into phenol and byproducts in the cracking reactor 2. The phenol produced after cracking is then recovered and reused in the subsequent phenol recovery tower 3, which can effectively reduce the production and operating costs of bisphenol A. Furthermore, the cracking recovery can effectively reduce the yield of byproducts and reduce the processing load of subsequent systems.

Claims

1. A substandard bisphenol A pyrolysis system, characterized in that, This includes a cracking agent storage tank, a cracking reactor, a phenol recovery tower, a phenol recovery cooler, and a phenol recovery storage tank; The pyrolysis reactor is equipped with a feed pipe, which has two branches. One branch connects to the outlet of the pyrolysis agent storage tank, and the other branch connects to the outlet of the unqualified bisphenol A solution in the production system. The bottom of the pyrolysis reactor is connected in sequence to a pyrolysis pump and a first circulation pipe, and the outlet of the first circulation pipe is connected to the top of the pyrolysis reactor. The first circulation pipeline is connected to the inlet of the phenol recovery tower via a discharge control valve on its side wall. The outlet of the phenol recovery tower is connected in sequence to the phenol recovery cooler and the phenol recovery storage tank.

2. The substandard bisphenol A pyrolysis system according to claim 1, characterized in that, The outer wall of the pyrolysis reactor is provided with a jacketed cavity, and steam is circulated into the jacketed cavity for heating.

3. The substandard bisphenol A pyrolysis system according to claim 2, characterized in that, The temperature inside the pyrolysis reactor is 185-195℃ and the pressure is 0.01-0.04 MPa.

4. The substandard bisphenol A pyrolysis system according to claim 1, characterized in that, The bottom of the phenol recovery tower is sequentially connected to a bottom pump, a second circulation pipeline, a heater, and the side wall of the phenol recovery tower.

5. The substandard bisphenol A pyrolysis system according to claim 4, characterized in that, The heater is equipped with a heat exchange coil, and steam is circulated through the heat exchange coil for heat tracing.

6. The non-conforming bisphenol A pyrolysis system according to any one of claims 1-5, characterized in that, A delivery pump and a cracking agent flow meter are installed on the branch line between the outlet of the cracking agent storage tank and the feed pipe.

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