Tail gas treatment system of dibutyl phthalate synthesis process

Abstract

The utility model belongs to the technical field of waste gas treatment, and particularly relates to a tail gas treatment system for a dibutyl phthalate synthesis process. Comprising a vacuum condenser, a vacuum buffer tank, a vacuum unit, a vacuum system liquid storage tank, a tail gas condenser, a vacuum tail gas absorption tank and an incinerator which are sequentially connected, and an inlet of the vacuum condenser is respectively connected with a non-condensable gas pipeline of a dealcoholization second condenser and a vacuum gas pipeline of a neutralization kettle; the waste gas condenser, the waste gas buffer tank and the waste gas fan are sequentially connected, an inlet of the waste gas condenser is connected with an esterification system waste gas pipeline and a dealcoholization system tail gas pipeline, and an outlet of the waste gas fan is connected to the incinerator; and the inlet of the waste gas buffer tank is respectively connected with an esterification system non-condensable gas pipeline and a finished product tank waste gas pipeline. By adopting a process route combining fractional condensation and absorption, the emission concentration of harmful substances in the tail gas can be effectively reduced. Meanwhile, the multi-procedure tail gas treatment process is integrated through modular design, equipment redundancy is reduced, and energy consumption is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of waste gas treatment, and in particular relates to a tail gas treatment system for a process of synthesizing dibutyl phthalate. Background Art

[0002] In the synthesis process of dibutyl phthalate (DBP), the esterification reaction and subsequent dealcoholization, neutralization and other processes will produce a large amount of non-condensable gas and waste gas containing organic matter. Traditional treatment methods usually use a single condensation or simple absorption device, which has problems such as low treatment efficiency, serious waste of resources, and poor system operation stability. For example, the direct discharge of uncondensed butanol, phthalic anhydride and other organic substances is easy to cause environmental pollution, and the recyclable materials in the condensate lack effective separation methods, resulting in raw material loss. In addition, the tail gas of different processes in the prior art needs to be treated independently, the equipment is redundant and the energy consumption is high, the condensation system lacks temperature stratification control, and high-boiling point substances are easy to be vaporized again, further reducing the treatment effect. Although some existing devices have tried to improve the purification effect through activated carbon adsorption and other methods, it is still difficult to adapt to the treatment requirements of multi-component tail gas in the dibutyl phthalate process. Therefore, the development of an integrated treatment system that can efficiently purify multi-source tail gas and adapt to complex working conditions has become a technical problem that needs to be solved in this field. Utility Model Content

[0003] In view of the above shortcomings in the prior art, the purpose of the utility model is to provide a tail gas treatment system for the process of synthesizing dibutyl phthalate, which can effectively remove organic matter with different boiling points and greatly reduce the emission concentration of harmful substances in the tail gas by adopting a process route combining graded condensation and absorption. At the same time, the multi-process tail gas treatment process is integrated through modular design, which reduces equipment redundancy, reduces energy consumption, realizes the recovery of raw materials such as butanol, and reduces the waste of resources.

[0004] The utility model is realized by adopting the following technical solutions:

[0005] The tail gas treatment system of the process for synthesizing dibutyl phthalate comprises a vacuum condenser, a vacuum buffer tank, a vacuum unit, a vacuum system liquid storage tank, a tail gas condenser, a vacuum tail gas absorption tank and an incinerator which are connected in sequence, wherein the inlet of the vacuum condenser is respectively connected to the non-condensable gas pipeline of the second condenser for dealcoholization and the vacuum gas pipeline of the neutralization kettle, and the inlet of the vacuum tail gas absorption tank is also connected to the tail gas pipeline of the drying tank; the system also comprises a waste gas condenser, a waste gas buffer tank and a waste gas fan which are connected in sequence, wherein the inlet of the waste gas condenser is respectively connected to the waste gas pipeline of the esterification system and the tail gas pipeline of the dealcoholization system, and the outlet of the waste gas fan is connected to the incinerator; and the inlet of the waste gas buffer tank is also respectively connected to the non-condensable gas pipeline of the esterification system and the waste gas pipeline of the finished product tank.

[0006] The bottom liquid outlet of the vacuum buffer tank is connected to the alcohol recovery sedimentation tank via a vacuum liquid collecting pump.

[0007] A softened water replenishment pipeline is arranged on the top of the vacuum system liquid storage tank, and a liquid outlet at the bottom is connected to a neutralization wastewater tank through a pipeline.

[0008] The bottom liquid outlet of the vacuum tail gas absorption tank is connected to the neutralization wastewater tank through a pipeline.

[0009] The bottom of the vacuum system liquid storage tank is also connected to the inlet of the vacuum system liquid cooler through a pipeline, the outlet of the vacuum system liquid cooler is connected to the working fluid inlet of the vacuum unit through a pipeline, and the outlet of the vacuum unit is refluxed to the vacuum system liquid storage tank through a pipeline, forming a closed-loop cooling circuit.

[0010] The vacuum condenser, tail gas condenser, waste gas condenser and vacuum system liquid cooler are respectively connected with a circulating water inlet pipeline and a circulating water return pipeline.

[0011] The tail gas treatment system of the process for synthesizing dibutyl phthalate has the following working principle:

[0012] The non-condensable gas from the second condenser of the dealcoholization and the vacuum gas from the neutralization kettle are respectively introduced into the vacuum condenser through the non-condensable gas pipeline of the second condenser of the dealcoholization and the vacuum gas pipeline of the neutralization kettle for preliminary condensation. The condensed gas-liquid mixture enters the vacuum buffer tank through the pipeline for gas-liquid separation. The separated waste liquid flows out from the liquid outlet at the bottom of the vacuum buffer tank and is transported to the alcohol recovery sedimentation tank by the vacuum liquid collecting pump. The separated non-condensable gas enters the vacuum unit through the pipeline and is then transported to the vacuum system liquid storage tank through the pipeline for further dissolution. As the amount of dissolved non-condensable gas increases, the liquid level of the vacuum system liquid storage tank continues to rise, and part of the waste liquid is discharged from the liquid outlet at the bottom of the vacuum system liquid storage tank to the neutralization wastewater tank to maintain the liquid level of the vacuum system liquid storage tank. The undissolved non-condensable gas enters the tail gas condenser through the pipeline from the top of the vacuum system liquid storage tank for secondary condensation, and then enters the vacuum tail gas absorption tank through the pipeline for deep absorption. The exhaust gas from the drying tank is merged into the vacuum exhaust gas absorption tank through the exhaust gas pipeline of the drying tank. The residual gas after absorption is merged into the exhaust gas fan outlet through the pipeline and finally transported to the incinerator for incineration. The absorption liquid of the vacuum exhaust gas absorption tank is discharged from the liquid outlet at the bottom to the neutralization wastewater tank.

[0013] The water in the vacuum system liquid storage tank needs to be replaced regularly, and softened water enters the tank through the softened water replenishment pipeline located at the top of the vacuum system liquid storage tank. As the tail gas is continuously absorbed, the water temperature in the vacuum system liquid storage tank continues to rise. The liquid in the tank enters the vacuum system liquid cooler through the pipeline to cool down, and then flows through the vacuum unit back to the vacuum system liquid storage tank, forming a closed-loop cooling circuit to ensure the constant system temperature.

[0014] The waste gas from the esterification system and the tail gas from the dealcoholization system enter the waste gas condenser through the esterification system waste gas pipeline and the dealcoholization system tail gas pipeline respectively. After cooling and condensation, the waste gas merges with the waste gas from the esterification system non-condensable gas pipeline and the finished product tank waste gas pipeline respectively and enters the waste gas buffer tank. After being pressurized by the waste gas fan, it is finally transported to the incinerator for incineration.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0016] (1) The tail gas treatment system of the process for synthesizing dibutyl phthalate described in the utility model deeply treats the tail gas generated by esterification, dealcoholization, neutralization and other links through an integrated process of multi-stage condensation, absorption and incineration. It adopts a vacuum and exhaust gas dual-line treatment mode, is compatible with exhaust gases from different sources, and uses closed-loop cooling and liquid level automatic adjustment technology to ensure stable operation of the system and avoid the risk of downtime caused by temperature fluctuations or abnormal liquid levels. The exhaust gas is treated in a closed manner throughout the process, which effectively reduces the corrosion of acidic gases to the pipeline. At the same time, residual organic matter and harmful components are completely decomposed through incineration, significantly reducing pollutant emissions and meeting environmental protection requirements;

[0017] (2) The tail gas treatment system of the process for synthesizing dibutyl phthalate described in the utility model realizes efficient material recovery through multi-stage condensation, dissolution and sedimentation separation of recyclable components such as butanol in the tail gas, thereby reducing the waste of raw materials. The wastewater from the vacuum system liquid storage tank and the vacuum tail gas absorption tank is directed to the neutralization wastewater tank for centralized treatment, realizing the recycling of resources and improving the economic efficiency of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the tail gas treatment system of the process for synthesizing dibutyl phthalate described in the utility model;

[0019] In the figure: 1. vacuum condenser; 2. vacuum buffer tank; 3. vacuum unit; 4. vacuum system liquid storage tank; 5. tail gas condenser; 6. vacuum tail gas absorption tank; 7. incinerator; 8. non-condensable gas pipeline of the second condenser of dealcoholization; 9. vacuum gas pipeline of neutralization kettle; 10. tail gas pipeline of blow-drying tank; 11. waste gas condenser; 12. waste gas buffer tank; 13. waste gas fan; 14. esterification system waste gas pipeline; 15. dealcoholization system tail gas pipeline; 16. esterification system non-condensable gas pipeline; 17. finished product tank waste gas pipeline; 18. vacuum liquid collecting pump; 19. alcohol recovery sedimentation tank; 20. softened water replenishment pipeline; 21. neutralization waste water tank; 22. vacuum system liquid cooler; 23. circulating water inlet pipeline; 24. circulating water return pipeline. DETAILED DESCRIPTION

[0020] In order to make the purpose and technical solution of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings.

[0021] Example 1

[0022] like Figure 1 As shown, the tail gas treatment system of the process for synthesizing dibutyl phthalate comprises a vacuum condenser 1, a vacuum buffer tank 2, a vacuum unit 3, a vacuum system liquid storage tank 4, a tail gas condenser 5, a vacuum tail gas absorption tank 6 and an incinerator 7 connected in sequence, wherein the inlet of the vacuum condenser 1 is respectively connected to a dealcoholization second condenser non-condensable gas pipeline 8 and a neutralization kettle vacuum gas pipeline 9, and the inlet of the vacuum tail gas absorption tank 6 is also connected to a blow-drying tank tail gas pipeline 10; further comprising a waste gas condenser 11, a waste gas buffer tank 12 and a waste gas fan 13 connected in sequence, wherein the inlet of the waste gas condenser 11 is respectively connected to an esterification system waste gas pipeline 14 and a dealcoholization system tail gas pipeline 15, and the outlet of the waste gas fan 13 is connected to the incinerator 7; the inlet of the waste gas buffer tank 12 is also respectively connected to an esterification system non-condensable gas pipeline 16 and a finished product tank waste gas pipeline 17.

[0023] The bottom liquid outlet of the vacuum buffer tank 2 is connected to the alcohol recovery sedimentation tank 19 via a vacuum liquid collecting pump 18 .

[0024] A softened water replenishment pipeline 20 is provided on the top of the vacuum system liquid storage tank 4, and a liquid outlet at the bottom is connected to a neutralization wastewater tank 21 through a pipeline.

[0025] The bottom liquid outlet of the vacuum tail gas absorption tank 6 is connected to the neutralization wastewater tank 21 through a pipeline.

[0026] The bottom of the vacuum system liquid storage tank 4 is also connected to the inlet of the vacuum system liquid cooler 22 through a pipeline, the outlet of the vacuum system liquid cooler 22 is connected to the working fluid inlet of the vacuum unit 3 through a pipeline, and the outlet of the vacuum unit 3 is refluxed to the vacuum system liquid storage tank 4 through a pipeline, forming a closed-loop cooling circuit.

[0027] The vacuum condenser 1, tail gas condenser 5, waste gas condenser 11 and vacuum system liquid cooler 22 are respectively connected with a circulating water inlet pipeline 23 and a circulating water return pipeline 24.

[0028] When working, the specific steps are as follows:

[0029] The non-condensable gas from the second condenser of the dealcoholization and the vacuum gas from the neutralization kettle are respectively introduced into the vacuum condenser 1 through corresponding pipelines for preliminary condensation. The condensed gas-liquid mixture is transported to the vacuum buffer tank 2, and the gas-liquid separation is completed in the tank. The separated waste liquid is discharged from the bottom liquid outlet of the vacuum buffer tank 2, and is transported to the recovery alcohol sedimentation tank 19 through the vacuum liquid collecting pump 18 to recover useful materials; the non-condensable gas enters the vacuum unit 3 for pressurization, and is then transported to the vacuum system liquid storage tank 4 for dissolution treatment. During the dissolution process, in order to maintain the liquid level balance, the excess waste liquid is discharged to the neutralization wastewater tank 21 through the bottom pipeline. The undissolved gas continues to enter the tail gas condenser 5 from the top of the vacuum system liquid storage tank 4 for secondary condensation, and then is transported to the vacuum tail gas absorption tank 6 for deep absorption. The tail gas generated by the drying tank is merged into the vacuum tail gas absorption tank 6 through the pipeline, and the residual gas after absorption merges with the gas in the outlet pipeline of the exhaust gas fan 13, and finally enters the incinerator 7 for incineration. The absorption liquid in the vacuum tail gas absorption tank 6 is discharged to the neutralization wastewater tank 21 through the bottom pipeline to complete liquid recovery.

[0030] The water in the vacuum system liquid storage tank 4 needs to be replaced regularly. During the replacement process, softened water is added to the vacuum system liquid storage tank 4 through the top softened water replenishment pipeline 20. During the dissolution process, in order to maintain the temperature of the system stable, the liquid in the vacuum system liquid storage tank 4 enters the vacuum system liquid cooler 22 through the bottom pipeline to cool down. The cooled liquid flows back to the vacuum system liquid storage tank 4 through the vacuum unit 3, forming a closed-loop circulation cooling circuit.

[0031] The waste gas from the esterification system and the tail gas from the dealcoholization system enter the waste gas condenser 11 through the corresponding pipelines for cooling and condensation. The condensed waste gas merges with the waste gas from the esterification system non-condensable gas pipeline 16 and the finished product tank waste gas pipeline 17 and enters the waste gas buffer tank 12 for temporary storage. The waste gas in the waste gas buffer tank 12 is pressurized by the waste gas fan 13 and then transported to the incinerator 7 for high-temperature incineration treatment.

Claims

1. A tail gas treatment system for a process for synthesizing dibutyl phthalate, characterized in that: The invention comprises a vacuum condenser (1), a vacuum buffer tank (2), a vacuum unit (3), a vacuum system liquid storage tank (4), a tail gas condenser (5), a vacuum tail gas absorption tank (6) and an incinerator (7) which are connected in sequence. The inlet of the vacuum condenser (1) is respectively connected to a dealcohol second condenser non-condensable gas pipeline (8) and a neutralization kettle vacuum gas pipeline (9), and the inlet of the vacuum tail gas absorption tank (6) is also connected to a blow-drying tank tail gas pipeline (10). The invention also comprises an exhaust gas condenser (11), an exhaust gas buffer tank (12) and an exhaust gas fan (13) which are connected in sequence. The inlet of the exhaust gas condenser (11) is respectively connected to an esterification system exhaust gas pipeline (14) and a dealcoholization system exhaust gas pipeline (15), and the outlet of the exhaust gas fan (13) is connected to the incinerator (7). The inlet of the exhaust gas buffer tank (12) is also respectively connected to an esterification system non-condensable gas pipeline (16) and a finished product tank exhaust gas pipeline (17).

2. The tail gas treatment system of the process for synthesizing dibutyl phthalate according to claim 1, characterized in that: The bottom liquid outlet of the vacuum buffer tank (2) is connected to the alcohol recovery sedimentation tank (19) via a vacuum liquid collection pump (18).

3. The tail gas treatment system of the process for synthesizing dibutyl phthalate according to claim 1, characterized in that: A softened water replenishment pipeline (20) is provided on the top of the vacuum system liquid storage tank (4), and a liquid outlet at the bottom is connected to a neutralization wastewater tank (21) via a pipeline.

4. The tail gas treatment system of the process for synthesizing dibutyl phthalate according to claim 1, characterized in that: The bottom liquid outlet of the vacuum tail gas absorption tank (6) is connected to the neutralization wastewater tank (21) through a pipeline.

5. The tail gas treatment system of the process for synthesizing dibutyl phthalate according to claim 1, characterized in that: The bottom of the vacuum system liquid storage tank (4) is also connected to the inlet of the vacuum system liquid cooler (22) via a pipeline, the outlet of the vacuum system liquid cooler (22) is connected to the working fluid inlet of the vacuum unit (3) via a pipeline, and the outlet of the vacuum unit (3) flows back to the vacuum system liquid storage tank (4) via the pipeline, thereby forming a closed-loop cooling circuit.

6. The tail gas treatment system for the process for synthesizing dibutyl phthalate according to claim 5, characterized in that: The vacuum condenser (1), tail gas condenser (5), waste gas condenser (11) and vacuum system liquid cooler (22) are respectively connected to a circulating water inlet pipeline (23) and a circulating water return pipeline (24).

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