Compressed nitrogen comprehensive utilization device and method for bisphenol A production post-treatment

Abstract

The invention provides a compressed nitrogen comprehensive utilization device for bisphenol A production post-treatment. The compressed nitrogen comprehensive utilization device comprises a vortex tube group and a washing tower, the vortex tube group is provided with a compressed nitrogen inlet, a hot nitrogen outlet and a cold nitrogen outlet; and the washing tower is communicated with the cold nitrogen outlet. The low-load refrigerant is obtained only through the vortex tube and original compressed nitrogen in bisphenol A production aftertreatment, the heat removal requirement of the washing tower in the compressed nitrogen comprehensive utilization device for bisphenol A production aftertreatment can be met, the problem that in the prior art, a series of freezing water supply and water return pipelines and valve pipe fittings need to be arranged is solved, and the refrigeration effect is good. According to the low-load heat removal device, introduction of new public engineering chilled water is avoided, the refrigerant introduction cost is reduced, the construction cost and the management cost are greatly reduced, and the low-load heat removal device can be widely used for low-load heat removal equipment which does not have circulating cooling water and needs refrigerants. In addition, the used vortex tube is a stable and reliable static equipment structure, and driving energy consumption does not need to be newly increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of bisphenol A production, and specifically relates to a device for comprehensive utilization of compressed nitrogen for post-production treatment of bisphenol A. In addition, the present invention also relates to a method for comprehensive utilization of compressed nitrogen for post-production treatment of bisphenol A. Background Art

[0002] Bisphenol A, also known as 2,2-bis(4-hydroxyphenyl)propane, is one of the most widely used industrial compounds. It is mainly used to produce a variety of polymer materials such as polycarbonate, epoxy resin, polysulfone resin, polyphenylene ether resin, unsaturated polyester resin, etc. It can also be used to produce fine chemical products such as plasticizers, flame retardants, antioxidants, heat stabilizers, rubber antioxidants, pesticides, coatings, etc. After the reactants synthesize bisphenol A through chemical reactions, a series of post-treatments are required, including washing and purifying the tail gas. In the chemical industry, washing towers are often used to wash and purify production tail gas. The production tail gas is sent to the bottom of the washing tower and flows upward, and the washing absorbent flows downward from the top of the tower. The two are countercurrently contacted on the packing or tower plate structure, and the target chemical substance is dissolved into the washing absorbent by using its solubility in the washing absorbent, completing the process of removing phenol and methyl mercaptan from the production tail gas.

[0003] In industry, excess scrubbing absorbent is generally used, and a pump is used to lift the scrubbing absorbent from the bottom of the tower to the top of the scrubbing tower for recycling. On the one hand, the scrubbing absorption process is usually an exothermic process in thermodynamics, and on the other hand, the processed production exhaust gas often has a certain temperature, so the temperature of the scrubbing absorbent will rise after multiple cycles. For most scrubbing absorbents, the increase in temperature will reduce the scrubbing absorption effect. Therefore, in some scrubbing tower application scenarios, a heat exchanger is required to remove heat from the scrubbing absorbent.

[0004] For washing absorbents using temperatures of 30-35°C or below, when the processed production tail gas itself has a certain temperature (such as 40-50°C), if its temperature is to be controlled to be stable, the use of conventional circulating cooling water (33-43°C) can no longer meet the temperature difference requirements. At this time, chilled water (7°C or lower) is generally used to remove heat. However, during the washing and absorption process, the absorbent obtains limited heat, that is, the corresponding heat removal load is generally not high. For example, the washing tower in the bisphenol A post-treatment device does not have a high demand for chilled water. Normal use of circulating cooling water can meet the heat removal requirements of process heat exchange, and the amount used is not large. However, the production device and post-treatment device of bisphenol A do not involve circulating cooling water. Even if a small amount of circulating cooling water is configured for its washing tower, a series of chilled water supply, return water pipes and valve fittings need to be configured in the device boundary area corridor, which greatly increases the construction cost and management cost.

[0005] In view of this, it has become an urgent problem for technical personnel in this field to develop a method that can meet the heat removal requirements of the washing tower in the bisphenol A post-treatment device without the need to configure a series of refrigerated water supply and return pipes and valve fittings. Summary of the invention

[0006] The purpose of the present invention is to solve the difficulties existing in the above-mentioned prior art, and provides a device for comprehensive utilization of compressed nitrogen for post-production treatment of bisphenol A. The cooling inner coil in the washing tower is connected to the cold nitrogen outlet of the vortex tube, and the original compressed nitrogen in the post-production treatment of bisphenol A is introduced into the vortex tube. The cold and hot gas separation effect of the vortex tube is used to obtain a low-load refrigerant, which can not only meet the heat removal demand of the washing tower in the bisphenol A post-treatment device, but also solve the problem of the need to configure a series of refrigerated water supply, return water pipelines and valve fittings in the prior art.

[0007] The present invention is achieved through the following technical solutions:

[0008] One of the purposes of the present invention is to provide a device for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, comprising:

[0009] A vortex tube group is provided with a compressed nitrogen inlet, a hot nitrogen outlet and a cold nitrogen outlet;

[0010] A washing tower is connected to the cold nitrogen outlet.

[0011] In a preferred embodiment of the present invention, the device further comprises a bisphenol A stripping tower, which is connected to a hot nitrogen outlet and a cold nitrogen outlet; a steam heater is provided at the inlet of the bisphenol A stripping tower.

[0012] In a preferred embodiment of the present invention, the device further comprises a bisphenol A stripping tower, and the bisphenol A stripping tower is connected to the hot nitrogen outlet.

[0013] In a preferred embodiment of the present invention, the device further comprises a granulation system, and the granulation system is connected to the hot nitrogen outlet and the cold nitrogen outlet.

[0014] In a preferred embodiment of the present invention, the device further comprises a granulation system, and the granulation system is connected to the cold nitrogen outlet.

[0015] In a preferred embodiment of the present invention, the device further comprises an oxygen-containing tail gas dilution system, and the oxygen-containing tail gas dilution system is connected to the hot nitrogen outlet and the cold nitrogen outlet.

[0016] In a preferred embodiment of the present invention, the device further comprises an oxygen-containing tail gas dilution system, and the oxygen-containing tail gas dilution system is connected to the cold nitrogen outlet.

[0017] In a preferred embodiment of the present invention, a control valve is provided at the hot nitrogen outlet.

[0018] The second object of the present invention is to provide a method for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, comprising:

[0019] S1: introducing compressed nitrogen into the vortex tube group to separate cold nitrogen and hot nitrogen;

[0020] S2: passing cold nitrogen into the scrubbing tower;

[0021] S3: The hot nitrogen and the cold nitrogen after heat exchange are mixed, respectively introduced into the granulation system and the oxygen-containing tail gas dilution system, and then introduced into the bisphenol A stripping tower after heating.

[0022] In a preferred embodiment of the present invention, comprising

[0023] S1: introducing compressed nitrogen into the vortex tube group to separate cold nitrogen and hot nitrogen;

[0024] S2: passing cold nitrogen into the scrubbing tower;

[0025] S3: Pass the hot nitrogen into the bisphenol A stripping tower; pass the cold nitrogen after heat exchange into the granulation system and the oxygen-containing tail gas dilution system respectively.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention only utilizes the vortex tube and the original compressed nitrogen in the post-processing of bisphenol A production to obtain low-load refrigerant, which can not only meet the heat removal demand of the washing tower in the comprehensive utilization device of compressed nitrogen for post-processing of bisphenol A production, but also solve the problem of the need to configure a series of refrigerated water supply, return water pipelines and valve pipes in the prior art, avoiding the introduction of new public engineering refrigerated water, not only reducing the cost of introducing refrigerant, but also greatly reducing the construction cost and management cost, and can be widely used in equipment without circulating cooling water and requiring refrigerant for low-load heat removal. In addition, the vortex tube used is a stable and reliable static equipment structure, and no additional driving energy consumption is required.

[0028] 2. Although the compressed nitrogen after heat exchange in the present invention loses some pressure, it can still be passed into the bisphenol A stripping tower, granulation system, and oxygen-containing tail gas dilution system for use. Furthermore, after the cold nitrogen and hot nitrogen after heat exchange are combined, the temperature is higher than the original compressed nitrogen, which can save the energy consumption of the steam heater at the inlet pipeline of the bisphenol A stripping tower, reducing the energy consumption cost. Furthermore, the hot nitrogen is directly passed into the bisphenol A stripping tower, which can save the steam heater at the inlet of the original bisphenol A stripping tower, further reducing the equipment cost and energy consumption cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a structural diagram of one embodiment of the device for comprehensive utilization of compressed nitrogen for post-treatment of bisphenol A production of the present invention;

[0030] Figure 2 It is a structural diagram of a washing tower, a vortex tube group and a washing absorbent circulating pump in the device for comprehensive utilization of compressed nitrogen for post-treatment of bisphenol A production of the present invention;

[0031] Figure 3 It is a structural diagram of another embodiment of the device for comprehensive utilization of compressed nitrogen for post-treatment of bisphenol A production of the present invention;

[0032] In the figure, 1-washing tower; 2-washing absorbent circulation pump; 3-vortex tube group; 4-cooling inner coil; 5-bisphenol A stripping tower; 6-granulation system; 7-oxygen-containing tail gas dilution system; 8-steam heater. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0034] like Figure 1 As shown, the present invention provides a device for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, comprising a vortex tube group 3, a washing tower 1, a bisphenol A stripping tower 5, a granulation system 6, and an oxygen-containing tail gas dilution system 7. Figure 2 The structure diagram of the washing tower 1, the vortex tube group 3 and the washing absorbent circulation pump 2 in the device for comprehensive utilization of compressed nitrogen for post-treatment of bisphenol A production is shown. Figure 2 As shown, a washing absorbent circulation pump 2 is provided outside the washing tower 1. The production tail gas is fed from the bottom of the washing tower 1 and moves upward to the top of the washing tower 1. Specifically, there is a washing absorbent at the bottom of the washing tower 1, which is pumped to the top of the washing tower 1 by the washing absorbent circulation pump 2, dispersed and flows downward to the bottom of the tower to complete the absorption of the production tail gas, and the washed tail gas is discharged from the top of the washing tower 1.

[0035] Wherein, a cooling inner coil 4 is provided in the washing absorbent liquid phase space in the tower kettle of the washing tower 1, and the inlet of the cooling inner coil 4 is connected to the vortex tube group 3 provided outside the washing tower 1. The vortex tube group 3 is provided with an inlet and two outlets, the inlet is a compressed nitrogen inlet, and the two outlets are respectively a cold nitrogen outlet and a hot nitrogen outlet. The compressed nitrogen inlet is connected to a public engineering pipeline originating from a bisphenol A production system through a pipeline, and the public engineering pipeline contains compressed nitrogen. After the compressed nitrogen enters the vortex tube group 3 from the compressed nitrogen inlet, it rotates and flows to the hot nitrogen outlet of the vortex tube group 3, a part of the high-temperature nitrogen moves to the hot nitrogen outlet, and the remaining low-temperature nitrogen is blocked, and then rotates in the opposite direction at the same speed, and flows to the cold nitrogen outlet of the vortex tube group 3. In this process, the low-temperature nitrogen and the high-temperature nitrogen undergo heat exchange, the inner annular airflow becomes very cold, and moves in the opposite direction to the cold nitrogen outlet of the vortex tube group 3, and the outer annular airflow becomes very hot, and moves to the hot nitrogen outlet of the vortex tube group 3.

[0036] In a preferred embodiment of the present invention, a control valve is provided at the hot nitrogen outlet. By adjusting the opening of the control valve, the ratio of hot nitrogen to cold nitrogen is adjusted, and the temperature of hot nitrogen and cold nitrogen is controlled. That is, the temperature of hot nitrogen and cold nitrogen can be controlled by adjusting the opening of the control valve. For example, when the required temperature of cold nitrogen is low, the opening of the control valve can be reduced, so that the gas output of hot nitrogen is small, the temperature of hot nitrogen is further increased, and the temperature of cold nitrogen is further reduced; when the required temperature of cold nitrogen is high, the opening of the control valve can be increased, so that the gas output of hot nitrogen is large, the temperature of hot nitrogen is further reduced, and the temperature of cold nitrogen is further increased.

[0037] In this embodiment, after the compressed nitrogen passes through the vortex tube group 3, the cold and hot gas separation effect of the vortex tube is utilized to adiabatically separate a portion of the cold nitrogen gas whose temperature is reduced to -10 to -20°C and a stream of hot nitrogen gas at 100 to 120°C. It should be noted that the temperatures of the cold nitrogen gas and the hot nitrogen gas in this embodiment are required by the process of the present invention and do not constitute a limitation of the present invention. The technicians can adjust the temperatures of the cold nitrogen gas and the hot nitrogen gas according to the actual process requirements.

[0038] The inlet of the cooling inner coil 4 is connected to the vortex tube group 3 provided outside the washing tower 1, specifically connected to the cold nitrogen outlet in the vortex tube group 3. Cold nitrogen at -10 to -20°C is passed into the cooling inner coil 4 to remove heat and cool the washing absorbent in the bottom of the washing tower 1. The cold nitrogen after heat exchange takes away the heat of the washing agent in the bottom of the washing tower 1.

[0039] In a preferred embodiment of the present invention, a cold nitrogen pipeline is provided at the outlet of the cooling inner coil 4, and the cold nitrogen after heat exchange enters the cold nitrogen pipeline. A hot nitrogen pipeline is provided at the hot nitrogen outlet of the vortex tube group 3, and the hot nitrogen generated by the vortex tube group 3 enters the hot nitrogen pipeline. The cold nitrogen pipeline and the hot nitrogen pipeline are connected, and both the cold nitrogen and the hot nitrogen enter the combined pipeline. The combined pipeline is respectively connected to the bisphenol A stripping tower 5, the granulation system 6, and the oxygen-containing tail gas dilution system 7 (such as Figure 1 It should be noted that after the cold nitrogen and hot nitrogen in the combined pipeline are mixed, the temperature is about 42-48°C, which is higher than the temperature of the compressed nitrogen in the utility pipeline.

[0040] A steam heater 8 is provided at the nitrogen inlet pipeline of the bisphenol A stripping tower 5, because the bisphenol A stripping tower 5 needs to use a gas of a certain temperature to blow the process medium to remove the light components in the process medium and complete the stripping effect of the stripping tower; specifically, the operating temperature of the bisphenol A stripping tower 5 is greater than 100°C, so the nitrogen needs to be heated at the nitrogen inlet pipeline. The steam heater 8 heats the mixed nitrogen to the required temperature, and then enters the bisphenol A stripping tower 5, so that the nitrogen strips the molten bisphenol A, and then removes the phenol in the bisphenol A product, so as to meet the required specifications of bisphenol A.

[0041] As mentioned above, after the cold nitrogen and hot nitrogen in the combined pipeline are mixed, the temperature is higher than the temperature of the compressed nitrogen in the utility pipeline. This is because the temperature of the cold nitrogen rises when removing heat from the scrubbing absorbent, so the temperature of the nitrogen in the combined pipeline is higher than the temperature of the compressed nitrogen in the utility pipeline. In this case, when the steam heater 8 heats the mixed nitrogen to a preset temperature, the energy consumption is lower than directly heating the compressed nitrogen in the utility pipeline to a preset temperature. In other words, the heat removed from the compressed nitrogen in the scrubbing tower 1 is also used, further reducing the energy consumption cost.

[0042] The nitrogen in the combined pipeline enters the granulation system 6 for cooling and granulation. Specifically, nitrogen granulation is a common practice in the bisphenol A industry. The molten bisphenol A (about 160-180°C) dripping from the top of the tower is cooled and granulated using a cooled gas phase (currently generally nitrogen). The cooled bisphenol A forms spherical particles with a diameter of 1.0-2 mm. It should be noted that the melting point of bisphenol A is between 158 and 169°C.

[0043] The nitrogen in the combined pipeline enters the oxygen-containing tail gas dilution system 7 to serve as an inert gas in the oxygen-containing tail gas dilution system 7. It should be noted that the oxygen-containing tail gas dilution system 7 needs to continuously introduce an inert gas to reduce the oxygen content in the tail gas, especially to avoid excessive oxygen content in the tail gas, thereby avoiding flash explosion downstream of the oxygen-containing tail gas dilution system 7.

[0044] In a more preferred embodiment of the present invention, Figure 3 As shown, a cold nitrogen pipeline is provided at the outlet of the cooling inner coil 4, and the cold nitrogen after heat exchange enters the cold nitrogen pipeline. The cold nitrogen pipeline is respectively connected to the granulation system 6 and the oxygen-containing tail gas dilution system 7. The cold nitrogen enters the granulation system 6 and the oxygen-containing tail gas dilution system 7 respectively, and its functions are the same as those mentioned above, which will not be repeated here. A hot nitrogen pipeline is provided at the hot nitrogen outlet of the vortex tube group 3, and the hot nitrogen generated by the vortex tube group 3 enters the hot nitrogen pipeline. The hot nitrogen pipeline is connected to the bisphenol A stripping tower 5, and the hot nitrogen at 100 to 120°C directly enters the bisphenol A stripping tower 5, and there is no need to set a steam heater 8 at the nitrogen inlet pipeline of the bisphenol A stripping tower 5, which further reduces the equipment cost and energy consumption cost.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment provides a method for comprehensively utilizing a compressed nitrogen comprehensive utilization device for post-treatment of bisphenol A production, which is used for a washing tower 1, a bisphenol A stripping tower 5, a granulation system 6 and an oxygen-containing tail gas dilution system 7.

[0047] A kind of tail gas in the production process of bisphenol A has a temperature of 40-50℃, and its main components are nitrogen, phenol, methyl mercaptan, etc. Phenol and methyl mercaptan are soluble in desalted water at room temperature. Therefore, desalted water at room temperature is used as a washing absorbent to wash and purify it. The phenol and methyl mercaptan absorbed by the washing absorbent can be returned to the device for separation and reuse.

[0048] The washing tower 1 is a packed tower, and the washing absorbent is controlled at 20-30°C in the tower kettle, so it is impossible to use 33°C circulating cooling water to remove heat, and a refrigerant with a temperature of at least 15°C or lower is required for heat removal.

[0049] Since all devices in the bisphenol A production process do not use chilled water below 15°C, and the heat required to remove the washing tower 1 during the absorption process is only 5-10kw, the amount of chilled water used is very small, and it is very uneconomical to set up chilled water supply and return pipe gallery pipelines for this chilled water. At the same time, considering that the bisphenol A production system requires 2000-4000Nm 3 The nitrogen is used for stripping, cooling granulation and dilution of oxygen-containing tail gas, and the pressure requirement is not high. Therefore, the design uses the 0.7MPaG low-pressure nitrogen at room temperature to pass through the vortex tube group 3 to generate hot nitrogen and cold nitrogen. After passing through the vortex tube group 3, the compressed nitrogen pressure is lost to 0.1-0.2MPaG, and an adiabatic isenthalpic change is performed to obtain a cold nitrogen of -10--20℃ and a hot nitrogen of 100-120℃.

[0050] Cold nitrogen is introduced into the cooling inner coil 4 in the kettle of the washing tower 1 as a refrigerant to remove heat from the washing absorbent in the kettle of the washing tower 1. After the cold nitrogen is removed from the heat, it is heated to 15-25°C and mixed with the hot nitrogen at 100-120°C to form 0.1-0.2MpaG low-pressure nitrogen at 42-48°C. It is transported to the bisphenol A stripping tower 5, the granulation system 6, and the oxygen-containing tail gas dilution system 7 through the combined pipeline for reuse.

[0051] The whole process does not consume external energy such as electric energy. Through the cold and hot gas separation effect of the vortex tube group 3, part of the nitrogen pressure is sacrificed to form a low-temperature refrigerant and remove the heat of the washing absorbent. At the same time, since the bisphenol A stripping tower 5 needs to heat the nitrogen, the removed heat is also used to a certain extent, further reducing the energy cost. With low equipment investment, the heat removal of the washing tower 1 is completed without additional energy consumption or even saving energy consumption.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0054] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A device for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, Features: include: A vortex tube group is provided with a compressed nitrogen inlet, a hot nitrogen outlet and a cold nitrogen outlet; A washing tower is connected to the cold nitrogen outlet.

2. The device according to claim 1, Features: The device also includes a bisphenol A stripping tower, which is connected to a hot nitrogen outlet and a cold nitrogen outlet; a steam heater is provided at the inlet of the bisphenol A stripping tower.

3. The device according to claim 1, Features: The device further comprises a bisphenol A stripping tower, which is connected to a hot nitrogen outlet.

4. The device according to claim 2 or 3, Features: The device further comprises a granulation system, which is connected to the hot nitrogen outlet and the cold nitrogen outlet.

5. The device according to claim 2 or 3, Features: The device further comprises a granulation system, which is connected to the cold nitrogen outlet.

6. The device according to claim 2 or 3, Features: The device also includes an oxygen-containing tail gas dilution system, which is connected to the hot nitrogen outlet and the cold nitrogen outlet.

7. The device according to claim 2 or 3, Features: The device also includes an oxygen-containing tail gas dilution system, and the oxygen-containing tail gas dilution system is connected to the cold nitrogen outlet.

8. The device according to claim 1, Features: A control valve is provided at the hot nitrogen outlet.

9. A method for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, Features: include S1: introducing compressed nitrogen into the vortex tube group to separate cold nitrogen and hot nitrogen; S2: passing cold nitrogen into the scrubbing tower; S3: The hot nitrogen and the cold nitrogen after heat exchange are mixed, respectively introduced into the granulation system and the oxygen-containing tail gas dilution system, and then introduced into the bisphenol A stripping tower after heating.

10. A method for comprehensive utilization of compressed nitrogen for post-processing of bisphenol A production, Features: include S1: introducing compressed nitrogen into the vortex tube group to separate cold nitrogen and hot nitrogen; S2: passing cold nitrogen into the scrubbing tower; S3: Pass the hot nitrogen into the bisphenol A stripping tower; pass the cold nitrogen after heat exchange into the granulation system and the oxygen-containing tail gas dilution system respectively.

Images