A polypropylene VOCs treatment and environmental protection recycling system

Abstract

The invention relates to the technical field of tail gas recovery and treatment, and in particular to an environmentally friendly recovery system for polypropylene VOCs treatment, comprising a flash evaporation replacement tail gas recovery system and a hopper activator nitrogen pressure delivery system, wherein the flash evaporation replacement tail gas recovery system comprises a bag filter, a vacuum compressor unit, a water vapor separation tank, a precondenser, a drying tower, a gas tail gas dehydration tower, a gas cabinet oxygen content analyzer, a gas oxygen content analyzer, a propylene recovery gas cabinet, a first connecting pipe, a second connecting pipe, a first exhaust cabinet switching valve and a first row of gas switching valves, and the hopper activator nitrogen pressure delivery system comprises a nitrogen buffer device and a nitrogen buffer tank, wherein the input end of the nitrogen buffer device is connected to the nitrogen tank, the output end of the nitrogen buffer device is connected to the nitrogen buffer tank, and the output end of the nitrogen buffer tank is connected to a nitrogen pipe network, so that propylene can be recovered, the enterprise cost is reduced, the enterprise economic efficiency is increased, the VOCs discharge is prevented, and the environmental protection is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas recovery and treatment, and in particular to a polypropylene VOCs treatment and environmentally friendly recovery system. Background Art

[0002] In the small-scale batch polypropylene production process, the polypropylene powder after the polymerization kettle reaction is sprayed into the flash kettle, and the propylene gas contained in the powder is directly discharged into the atmosphere after vacuuming and nitrogen replacement in the flash kettle. In addition, the activator added to the polymerization kettle reaction has excessive residual pressure due to the residual propylene in the activator hopper during the feeding process. The internal pressure of the hopper needs to be diluted by a kerosene tank and discharged into the atmosphere to reduce the internal residual pressure. Then, nitrogen presses the activator into the activator hopper, which will also cause VOCs emissions.

[0003] Unorganized emissions not only cause propylene loss but also lead to environmental pollution. In recent years, with the reduction of profit margins and national environmental protection requirements, flash kettle replacement tail gas recovery has begun to attract attention in the industry. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a polypropylene VOCs treatment and environmental protection recovery system which can recycle propylene, reduce enterprise costs, increase enterprise economic efficiency, prevent VOCs efflux, and improve environmental protection.

[0006] (II) Technical solution

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a polypropylene VOCs treatment and environmental protection recovery system, comprising a flash replacement tail gas recovery system and a hopper activator nitrogen pressure delivery system, the flash replacement tail gas recovery system comprising a bag filter, a vacuum compressor unit, a water vapor separation tank, a pre-condenser, a drying tower, a gas tail gas dehydration tower, a gas cabinet oxygen content analyzer, a gas oxygen content analyzer and a propylene recovery gas cabinet, the input end of the bag filter is connected to the discharge tail gas of the flash kettle and the vacuum pump, the output end of the bag filter is connected to the input end of the vacuum compressor unit, the input end of the water vapor separation tank is connected to the output end of the vacuum compressor unit, and the output end of the water vapor separation tank is provided with a first connecting pipe and a second connecting pipe, and the first connecting pipe and the second connecting pipe are respectively connected to the pre-condenser. The input end of the condenser is connected to the input end of the gas tail gas dehydration tower, and the first exhaust cabinet switching valve and the first row of gas switching valves are respectively arranged on the first connecting pipe and the second connecting pipe. The input end and output end of the drying tower are respectively connected to the output end of the pre-condenser and the input end of the gas cabinet oxygen content analyzer. The output end of the gas cabinet oxygen content analyzer is connected to the propylene recovery gas cabinet, the input end of the gas oxygen content analyzer is connected to the output end of the gas tail gas dehydration tower, and the output end of the gas oxygen content analyzer is connected to the gas system; the hopper activator nitrogen pressure delivery system includes a nitrogen buffer device and a nitrogen buffer tank. The input end of the nitrogen buffer device is connected to the nitrogen tank, the output end of the nitrogen buffer device is connected to the nitrogen buffer tank, and the output end of the nitrogen buffer tank is connected to the nitrogen pipeline network.

[0008] Preferably, an exhaust cabinet delivery pipeline is provided between the gas cabinet oxygen content analyzer and the propylene recovery gas cabinet, and a second exhaust cabinet switching valve is provided on the exhaust cabinet delivery pipeline. The exhaust cabinet delivery pipeline is connected to a gas cabinet exhaust pipeline, and a gas cabinet exhaust switching valve is provided on the gas cabinet exhaust pipeline.

[0009] Preferably, the gas system includes a fuel gas delivery pipeline, a gas delivery pipeline, and a mixer. The input end of the gas delivery pipeline is connected to the output end of the gas oxygen content analyzer, the output end of the gas delivery pipeline is provided with a mixer, and a second row of gas switching valves and a gas flow controller are provided on the gas delivery pipeline. The gas delivery pipeline is connected to a gas exhaust pipeline, and a gas exhaust switching valve is provided on the gas exhaust pipeline. The output end of the fuel gas delivery pipeline is connected to the mixer, and a fuel gas distribution flowmeter, a fuel gas distribution regulating valve and a fuel gas distribution flow controller are provided on the fuel gas delivery pipe. The output end of the mixer is connected to the gas network, and a gas network pressure controller is provided at the output end of the mixer.

[0010] Preferably, the vacuum compressor unit may also be a piston vacuum compressor, in which case the water vapor separation tank and the drying tower may be removed.

[0011] (III) Beneficial effects

[0012] Compared with the prior art, the present invention provides a polypropylene VOCs treatment and environmental protection recycling system, which has the following beneficial effects:

[0013] 1. The polypropylene VOCs treatment and environmental protection recovery system, after the flash kettle spraying is completed, the tail gas rich in propylene passes through the bag filter to remove the residual polypropylene dust in the gas, and then is transported to the water vapor separation tank for gas-water separation after the vacuum compressor unit boosts the pressure, and then enters the pre-condenser to remove free water after the exhaust cabinet switching valve is opened, and then enters the drying tower to remove the moisture in the propylene gas by the desiccant filled inside to control it below 100ppm, and then enters the propylene recovery gas cabinet to recover propylene after passing the gas cabinet oxygen content analyzer test; the propylene content of the flash kettle decreases after nitrogen replacement, and the tail gas with no recovery value passes through the bag filter to remove the residual polypropylene dust in the gas, and then is boosted by the vacuum compressor unit and separated by the water vapor separation tank, and the gas exhaust switching valve is opened to enter the gas tail gas dehydration tower to remove free water, and then is discharged into the gas system after passing the gas oxygen content analyzer test, so as to realize the automatic switching control of the recovered gas and the discharged gas, reduce the polypropylene processing loss rate, and prevent VOCs from being discharged;

[0014] 2. The polypropylene VOCs treatment and environmentally friendly recycling system uses 2.0MPa high-pressure nitrogen or 16MPa high-pressure nitrogen from a bottle group, which is reduced to 1.0MPa by a nitrogen pressure reducing device and then enters the nitrogen pipeline to directly pressurize the activator. The activator hopper realizes fully enclosed environmentally friendly filling without external emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the flash replacement tail gas recovery system of the present invention;

[0016] Figure 2 It is a structural schematic diagram of the nitrogen pressure delivery system for the hopper activator of the present invention;

[0017] Markings in the attached figure: 1. Bag filter; 2. Vacuum compressor unit; 3. Water vapor separation tank; 4. Pre-condenser; 5. Drying tower; 6. Gas tail gas dehydration tower; 7. Gas cabinet oxygen content analyzer; 8. Gas oxygen content analyzer; 9. Propylene recovery gas cabinet; 10. First exhaust cabinet switching valve; 11. First row of gas switching valve; 12. Nitrogen buffer equipment; 13. Nitrogen buffer tank; 14. Exhaust cabinet delivery pipeline; 15. Second exhaust cabinet switching valve; 16. Gas cabinet emptying pipeline; 17. Gas cabinet emptying switching valve; 18. Fuel gas delivery pipeline; 19. Gas delivery pipeline; 20. Mixer; 21. Second row of gas switching valve; 22. Gas flow controller; 23. Gas emptying pipeline; 24. Gas emptying switching valve; 25. Flow meter for distribution; 26. Fuel gas regulating valve for distribution; 27. Fuel gas distribution flow controller; 28. Gas network pressure controller. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-2The present invention provides a polypropylene VOCs treatment and environmentally friendly recovery system, comprising a flash replacement tail gas recovery system and a hopper activator nitrogen pressure delivery system, wherein the flash replacement tail gas recovery system comprises a bag filter 1, a vacuum compressor unit 2, a water vapor separation tank 3, a precondenser 4, a drying tower 5, a gas tail gas dehydration tower 6, a gas cabinet oxygen content analyzer 7, a gas oxygen content analyzer 8 and a propylene recovery gas cabinet 9, wherein the input end of the bag filter 1 is connected to the discharge tail gas of the flash kettle and the vacuum pump, the output end of the bag filter 1 is connected to the input end of the vacuum compressor unit 2, the input end of the water vapor separation tank 3 is connected to the output end of the vacuum compressor unit 2, and the output end of the water vapor separation tank 3 is provided with a first connecting pipe and The second connecting pipe, the first connecting pipe and the second connecting pipe are respectively connected to the input end of the precondenser 4 and the input end of the gas tail gas dehydration tower 6, and the first exhaust cabinet switching valve 10 and the first row of gas switching valves 11 are respectively arranged on the first connecting pipe and the second connecting pipe, the input end and the output end of the drying tower 5 are respectively connected to the output end of the precondenser 4 and the input end of the gas cabinet oxygen content analyzer 7, the output end of the gas cabinet oxygen content analyzer 7 is connected to the propylene recovery gas cabinet 9, the input end of the gas oxygen content analyzer 8 is connected to the output end of the gas tail gas dehydration tower 6, and the output end of the gas oxygen content analyzer 8 is connected to the gas system. After the flash kettle spraying is completed, the tail gas rich in propylene is dehydrated through the bag filter 1. The residual polypropylene dust in the gas is removed, and then the vacuum compressor unit 2 is pressurized and transported to the water vapor separation tank 3 for gas-water separation. After the exhaust cabinet switching valve is opened, it enters the pre-condenser 4 to remove free water, and then enters the drying tower 5 where the desiccant filled inside removes the moisture in the propylene gas and controls it below 100ppm. After passing the test of the gas cabinet oxygen content analyzer 7, it enters the propylene recovery gas cabinet 9 to recover propylene; the flash kettle is filled with nitrogen for replacement, and the propylene content decreases. The tail gas with no recovery value passes through the bag filter 1 to remove the residual polypropylene dust in the gas, and then after the vacuum compressor unit 2 is pressurized, the gas and water are separated by the water vapor separation tank 3. After the gas exhaust switching valve is opened, it enters the gas tail gas dehydration tower 6 to remove free After being separated from the water and tested by the gas oxygen content analyzer 8 and qualified, it is discharged into the gas system to realize automatic switching control between the recovered gas and the discharged gas, reduce the loss rate of polypropylene processing, and prevent VOCs from being discharged; the hopper activator nitrogen pressure delivery system includes a nitrogen buffer device 12 and a nitrogen buffer tank 13, the input end of the nitrogen buffer device 12 is connected to the nitrogen tank, the output end of the nitrogen buffer device 12 is connected to the nitrogen buffer tank 13, the output end of the nitrogen buffer tank 13 is connected to the nitrogen pipeline network, and the high-pressure nitrogen of 2.0MPa or the high-pressure nitrogen of 16MPa in the bottle group is reduced to 1.0MPa by the pressure reducing nitrogen device and then enters the nitrogen pipeline network to directly pressure-deliver the activator, and the activator hopper realizes a fully enclosed and environmentally friendly filling without external discharge.

[0020] The present invention discloses a polypropylene VOCs treatment and environmental protection recovery system, wherein an exhaust cabinet delivery pipeline 14 is connected between the gas cabinet oxygen content analyzer 7 and the propylene recovery gas cabinet 9, and a second exhaust cabinet switching valve 15 is provided on the exhaust cabinet delivery pipeline 14, and a gas cabinet emptying pipeline 16 is connected to the exhaust cabinet delivery pipeline 14, and a gas cabinet emptying switching valve 17 is provided on the gas cabinet emptying pipeline 16, and the gas system comprises a fuel gas delivery pipeline 18, a gas delivery pipeline 19, and a mixer 20, the input end of the gas delivery pipeline 19 is connected to the output end of the gas oxygen content analyzer 8, the output end of the gas delivery pipeline 19 is connected with the mixer 20, and a second row of gas switching valves 21 and a gas flow controller 22 are provided on the gas delivery pipeline 19, a gas emptying pipeline 23 is connected to the gas delivery pipeline 19, and a gas emptying switching valve 24 is provided on the gas emptying pipeline 23, and the output end of the fuel gas delivery pipeline 18 is connected to the gas delivery pipeline 19. It is connected to the mixer 20, and a fuel gas distribution flow meter 25, a fuel gas distribution regulating valve 26 and a fuel gas distribution flow controller 27 are arranged on the fuel gas transmission pipe. The output end of the mixer 20 is connected to the gas network, and a gas network pressure controller 28 is arranged at the output end of the mixer 20; the fuel gas distribution flow controller adjusts the flow through the fuel gas distribution regulating valve 26 and measures it through the distribution flow meter 25 according to the indication of the gas flow controller 22, and then a certain amount of fuel gas is logically and proportionally distributed as the gas distribution gas and discharged into the mixer 20 together. The gas network pressure controller 27 monitors the gas system pressure. If the pressure exceeds the fixed value, the system control will close the gas emptying switching valve 24 and simultaneously close the fuel gas distribution regulating valve 26. If the above gas oxygen content analyzer 8 detects that the oxygen content in the gas exceeds the standard, the second row gas switching valve 21 and the gas emptying switching valve 24, the second exhaust cabinet switching valve 15 and the gas cabinet emptying switching valve 17 will automatically switch to directly empty.

[0021] In the polypropylene VOCs treatment and environmentally friendly recycling system of the present invention, the vacuum compressor unit 2 can also use a piston vacuum compressor. In this case, the water vapor separation tank 3 and the drying tower 5 can be removed, thereby reducing investment and cost.

[0022] The polypropylene VOCs treatment and environmentally friendly recycling system of the present invention is used. After the flash kettle spraying is completed, the tail gas rich in propylene passes through the bag filter 1 to remove the residual polypropylene dust in the gas, and then is pressurized by the vacuum compressor unit 2 and transported to the water vapor separation tank 3 for gas-water separation. After the exhaust cabinet switching valve is opened, it enters the pre-condenser 4 to remove free water, and then enters the drying tower 5. The desiccant filled inside removes the moisture in the propylene gas and controls it to be below 100ppm, and then is detected by the gas cabinet oxygen content analyzer 7. After passing the test, it enters the propylene recovery gas cabinet 9 to recover propylene; after the flash kettle is filled with nitrogen for replacement, the propylene content decreases, and the tail gas with no recovery value passes through the bag filter 1 to remove the residual polypropylene dust in the gas, and then is pressurized by the vacuum compressor unit 2 and separated by the water vapor separation tank 3. After the gas discharge switching valve is opened, it enters the gas tail gas dehydration tower 6 to remove free water, and then is discharged into the gas system after passing the gas oxygen content analyzer 8. The fuel gas distribution flow controller 27 is based on the instructions of the gas flow controller 22, and after the distribution of fuel gas The material gas regulating valve 26 adjusts the flow rate and after being measured by the combustion flow meter 25, a certain amount of fuel gas is added as the gas combustion gas according to the logic and proportion and discharged into the mixer 20 together. The gas pipe network pressure controller 28 monitors the gas system pressure. If the pressure exceeds the fixed value, the system control will close the gas emptying switching valve 24 and the combustion fuel gas regulating valve 26 at the same time. If the above gas oxygen content analyzer 8 detects that the oxygen content in the gas exceeds the standard, the second row of gas switching valves 21 and the gas emptying switching valve 24, the second exhaust cabinet cut The change valve 15 and the gas cabinet emptying switching valve 17 automatically switch to direct emptying, realizing automatic switching control of the recovered gas and the exhaust gas, reducing the loss rate of polypropylene processing, eliminating the external discharge of VOCs, and realizing fully automatic linkage control with the flash kettle replacement, reducing the configuration of 4 people at the flash replacement post and reducing personnel costs; high-pressure nitrogen 2.0MPa or bottle group high-pressure nitrogen 16MPa is reduced to 1.0MPa by the nitrogen pressure reducing equipment and then enters the nitrogen pipeline network to directly pressurize the activator, and the activator feeding hopper realizes fully enclosed and environmentally friendly filling without external emissions.

[0023] In summary, the polypropylene VOCs treatment and environmentally friendly recycling system of the present invention reduces the polypropylene propylene processing loss rate by 2-3kg / tPP; realizes the VOCs unorganized emission treatment through flash replacement and activator feeding hopper tail gas; the transformation on the original equipment has a short process, low investment and quick effect; realizes full-automatic linkage control with flash kettle replacement, reduces the flash replacement post configuration and reduces the personnel cost; realizes DCS automatic control and alarm, has a high degree of automation and good safety; realizes the reduction of propylene processing loss rate and improves economic benefits, solves the unorganized emission of polypropylene VOCs, improves the automation level, reduces the personnel cost, and improves the operation stability and safety.

[0024] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0025] The electrical components mentioned in this article are all connected to an external main controller and 220V mains electricity, and the main controller can be a conventional known device for controlling a computer or the like.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polypropylene VOCs treatment and environmental protection recycling system, characterized in that: The invention comprises a flash replacement tail gas recovery system and a hopper activator nitrogen pressure delivery system, wherein the flash replacement tail gas recovery system comprises a bag filter (1), a vacuum compressor unit (2), a water vapor separation tank (3), a precondenser (4), a drying tower (5), a gas tail gas dehydration tower (6), a gas cabinet oxygen content analyzer (7), a gas oxygen content analyzer (8) and a propylene recovery gas cabinet (9), wherein the input end of the bag filter (1) is connected to the exhaust gas discharged from the flash kettle and the vacuum pump, the output end of the bag filter (1) is connected to the input end of the vacuum compressor unit (2), the input end of the water vapor separation tank (3) is connected to the output end of the vacuum compressor unit (2), and the output end of the water vapor separation tank (3) is provided with a first connecting pipe and a second connecting pipe, wherein the first connecting pipe and the second connecting pipe are respectively connected to the input end of the precondenser (4) and the input end of the gas tail gas dehydration tower (6). , and a first exhaust cabinet switching valve (10) and a first row of gas switching valves (11) are respectively arranged on the first connecting pipe and the second connecting pipe, the input end and the output end of the drying tower (5) are respectively connected to the output end of the pre-condenser (4) and the input end of the gas cabinet oxygen content analyzer (7), the output end of the gas cabinet oxygen content analyzer (7) is connected to the propylene recovery gas cabinet (9), the input end of the gas oxygen content analyzer (8) is connected to the output end of the gas tail gas dehydration tower (6), and the output end of the gas oxygen content analyzer (8) is connected to the gas system; the hopper activator nitrogen pressure delivery system includes a nitrogen buffer device (12) and a nitrogen buffer tank (13), the input end of the nitrogen buffer device (12) is connected to the nitrogen tank, the output end of the nitrogen buffer device (12) is connected to the nitrogen buffer tank (13), and the output end of the nitrogen buffer tank (13) is connected to the nitrogen pipeline network; The gas system comprises a fuel gas delivery pipeline (18), a gas delivery pipeline (19), and a mixer (20); the input end of the gas delivery pipeline (19) is connected to the output end of the gas oxygen content analyzer (8); the output end of the gas delivery pipeline (19) is connected to the mixer (20); a second row of gas switching valves (21) and a gas flow controller (22) are provided on the gas delivery pipeline (19); and a gas exhaust valve (21) is provided on the gas delivery pipeline (19). A pipeline (23) is connected to the gas exhaust pipeline (23), and a gas exhaust switching valve (24) is arranged on the gas exhaust pipeline (23); the output end of the fuel gas delivery pipeline (18) is connected to the mixer (20), and a fuel gas distribution flow meter (25), a fuel gas distribution regulating valve (26) and a fuel gas distribution flow controller (27) are arranged on the fuel gas delivery pipe; the output end of the mixer (20) is connected to the gas pipeline network, and a gas pipeline network pressure controller (28) is arranged at the output end of the mixer (20).

2. A polypropylene VOCs treatment and environmental protection recycling system according to claim 1, characterized in that: An exhaust cabinet delivery pipeline (14) is provided between the gas cabinet oxygen content analyzer (7) and the propylene recovery gas cabinet (9), and a second exhaust cabinet switching valve (15) is provided on the exhaust cabinet delivery pipeline (14). A gas cabinet exhaust pipeline (16) is provided in communication with the exhaust cabinet delivery pipeline (14), and a gas cabinet exhaust switching valve (17) is provided on the gas cabinet exhaust pipeline (16).

3. A polypropylene VOCs treatment and environmental protection recycling system according to claim 2, characterized in that: The vacuum compressor unit (2) uses a piston vacuum compressor, and in this case the water vapor separation tank (3) and the drying tower (5) are removed.

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