CN212151624U - Nitrogen recycling system - Google Patents

Abstract

The utility model is suitable for a gaseous recycle technical field provides a nitrogen gas recovery cyclic utilization system. The nitrogen recycling system comprises a gas classification transportation module, a gas mixing and collecting module, a compression and pressurization module, a condensation and separation module and a pressure reduction and reuse module. The utility model provides a nitrogen recovery cyclic utilization system, realize carrying out gas classification and transportation earlier with the waste nitrogen of different pressures through setting up gas classification transportation module, it realizes carrying out gas mixing collection to the waste nitrogen of different pressures to set up gas mixing collection module, it realizes compressing pressure boost and condensation separation to the mixed waste gas after mixing to set up compression pressure boost module and condensation separation module, realize the pressure reduction separation through setting up step-down retrieval and utilization module at last and obtain high-pressure gas and low-pressure gas, finally realize the cyclic recycle of the waste nitrogen of multiple different pressures in one set of system, practice thrift the cost of recovery.

Description

Nitrogen recycling system

Technical Field

The utility model belongs to the technical field of gas recovery utilizes, more specifically say, relate to a nitrogen gas recovery cyclic utilization system.

Background

In pharmaceutical and chemical industries, nitrogen is used in places containing solvents and having explosion hazards, and in the fields of hot drying gas, protective gas, material pressing gas, pressure filtration gas, back blowing gas and the like. The used nitrogen waste gas contains organic solvent, so that direct discharge is not allowed, the cost of the nitrogen is 0.8-1.0 yuan/Nm 3, and the production cost is increased due to the direct discharge of a large amount of nitrogen. For this purpose, the nitrogen is recycled.

At present, a common nitrogen recycling process mainly adopts a condensation dehumidification mode, a recycling system only recycles nitrogen with the same pressure, if nitrogen with different pressures needs to be recycled, two sets of circulating systems need to be built to respectively treat nitrogen with two pressures, and the recycling cost is extremely high.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a nitrogen gas recovery cyclic utilization system aims at solving current cyclic utilization system and can not carry out simultaneous cyclic utilization's technical problem to the solvent-containing gas of two kinds of pressure.

In order to achieve the above object, the utility model adopts the technical scheme that a nitrogen gas recycling system is provided, include:

the gas classification and transportation module is used for separately conveying the classified high-pressure waste gas and low-pressure waste gas;

the gas mixing and collecting module is used for mixing and collecting the high-pressure waste gas and the low-pressure waste gas;

the compression and pressurization module is used for carrying out compression and pressurization treatment on the mixed waste gas mixed and collected by the gas mixing and collecting module;

the condensation separation module is used for condensing the mixed waste gas pressurized by the compression pressurization module to separate gas in the mixed waste gas from a solvent; and

and the pressure reduction recycling module is used for reducing pressure and separating the gas separated by the condensation separation module into high-pressure gas and low-pressure gas, and conveying the high-pressure gas and the low-pressure gas to flow into high-pressure gas equipment and low-pressure gas equipment respectively.

Further, the gas classification module comprises:

the two ends of the high-pressure mixed gas conveying channel are respectively communicated with a high-pressure gas device and the gas mixing and collecting module;

the two ends of the low-pressure mixed gas conveying channel are respectively communicated with a low-pressure gas device and the gas mixing and collecting module;

the first condenser is connected in series with the high-pressure mixed gas conveying channel and is used for cooling the high-pressure mixed gas; and

and the first gas-liquid separator is connected in series with the high-pressure mixed gas conveying channel, is positioned behind the first condenser and is used for performing primary separation operation of gas and solvent on the high-pressure mixed gas.

Further, the gas classification module further comprises a pressure compensation gas conveying channel and a first pressure regulating valve connected in series to the pressure compensation gas conveying channel, the pressure compensation gas conveying channel is communicated with the high-pressure mixed gas conveying channel, and the first pressure regulating valve controls the gas pressure in the pressure compensation gas conveying channel by receiving the gas outlet pressure information of the gas mixing and collecting module.

Further, the gas mixture collection module includes an injector having an injector first inlet, an injector second inlet, and an injector outlet, the injector first inlet and the injector second inlet respectively communicating with the low pressure mixed gas delivery passage and the high pressure mixed gas delivery passage, the injector outlet communicating with the compression and pressurization module.

Further, the condensation separation module comprises a second condenser used for condensing the pressurized mixed gas and a second gas-liquid separator used for separating gas and liquid of the mixed gas cooled by the second condenser, and a gas outlet of the second gas-liquid separator is communicated with the pressure reduction recycling module.

Further, the compression and pressurization module comprises a compressor, the compressor is a liquid ring compressor, the compressor is provided with a low-pressure air inlet, a high-pressure air outlet and a solvent inlet, the low-pressure air inlet is communicated with the gas mixing and collecting module, the high-pressure air outlet is communicated with the second condenser, and the solvent inlet is communicated with a liquid outlet of the second gas-liquid separator.

Further, the condensation separation module further comprises a third gas-liquid separator, wherein an air inlet of the third gas-liquid separator is communicated with the high-pressure air outlet, an air outlet of the third gas-liquid separator is communicated with the second condenser, a liquid inlet of the third gas-liquid separator is communicated with a liquid outlet of the second gas-liquid separator, and a liquid outlet of the third gas-liquid separator is communicated with a liquid inlet of the solvent;

the third gas-liquid separator is also provided with an overflow pipeline, the third gas-liquid separator and the compressor form a communicating vessel structure, and the liquid level of the solvent in the third gas-liquid separator is as high as the liquid level of the solvent in the compressor.

Further, the condensation separation module further comprises a heat exchanger, the heat exchanger comprises a heat exchange box body and a heat pipe provided with working liquid, the heat exchange box body is provided with a condensation cavity and an evaporation cavity which are not communicated with each other, the heat pipe comprises a condensation section and an evaporation section communicated with the condensation section, the condensation section is arranged in the condensation cavity, the evaporation section is arranged in the evaporation cavity, the evaporation cavity is communicated with an air outlet of the third gas-liquid separator and the second condenser respectively, and the condensation cavity is communicated with the second gas-liquid separator and the pressure reduction recycling module respectively;

the working liquid flows from the evaporation section to the condensation section in the heat pipe, the pressurized mixed gas is cooled in the evaporation cavity, and the gas separated by the second gas-liquid separator is heated in the condensation cavity.

Further, the depressurization recycling module comprises:

the two ends of the high-pressure gas returning channel are respectively communicated with the high-pressure gas equipment and the condensation separation module;

the two ends of the low-pressure gas return channel are respectively communicated with the low-pressure gas equipment and the condensation separation module;

the first pressure reducing valve is connected in series in the high-pressure gas returning channel and is used for reducing the pressure of the gas separated by the condensation separation module into high-pressure gas; and

and the second pressure reducing valve is connected in the low-pressure gas returning channel in series and used for reducing the pressure of the gas separated by the condensation separation module into low-pressure gas.

The utility model provides a nitrogen recovery cyclic utilization system, compared with the prior art, realize carrying out gas classification and transportation earlier with the waste nitrogen of different pressures through setting up gas classification transportation module, it realizes carrying out gas mixing collection to the waste nitrogen of different pressures to set up gas mixing collection module, it realizes compressing pressure boost and condensation separation to the mixed waste gas after mixing to set up compression pressure boost module and condensation separation module, realize the step-down separation through setting up step-down retrieval and utilization module at last and obtain high-pressure gas and low-pressure gas, finally realize the cyclic recycle of the waste nitrogen of multiple different pressures on one set of system, practice thrift the cost of recovery.

Drawings

Fig. 1 is a schematic diagram of a nitrogen recycling system provided in an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating the connection of the gas classification module, the gas mixture collection module and the compression pressurization module of FIG. 1;

FIG. 3 is a schematic diagram illustrating the connection between the compression and pressurization module and the condensation separation module in FIG. 1;

FIG. 4 is a schematic diagram of the heat exchanger of FIG. 3;

fig. 5 is a process flow diagram of the nitrogen recycling system provided by the embodiment of the present invention.

In the figure: 1. a high pressure mixed gas delivery passage; 2. a low pressure mixed gas delivery passage; 3. a pressure compensating gas delivery passage; 4. a first pressure regulating valve; 5. a first condenser; 6. a first gas-liquid separator; 7. an ejector; 8. a compressor; 9. a second condenser; 10. a second gas-liquid separator; 11. a heat exchanger; 1101. a heat pipe; 11011. a condensing section; 11012. an evaporation section; 1102. a heat exchange box body; 12. a third gas-liquid separator; 13. an overflow line; 14. a U-shaped pipeline; 15. a high-pressure gas return passage; 16. a low-pressure gas return passage; 17. a first pressure reducing valve; 18. a second pressure reducing valve; 19. a first trap; 20. a first check valve; 21. a second check valve; 22. a third condenser; 23. a second trap; 24. high-pressure gas utilization equipment; 25. low-pressure gas utilization equipment; 26. a compensating pressure limiting valve.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It should be noted that the terms "length," "width," "height," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," "tail," and the like, are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and for simplicity in description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.

It is also noted that, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," "disposed," and the like are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Further, "plurality" or "a plurality" means two or more unless specifically limited otherwise.

In order to better explain the nitrogen recycling system provided by the embodiment of the utility model, the process flow is explained first. Fig. 5 shows a flow chart of the gas recycling process, and the process is detailed as follows:

and S100, carrying out gas classification transportation, namely classifying the high-pressure mixed gas generated by the high-pressure gas equipment and the low-pressure mixed gas generated by the low-pressure gas equipment into high-pressure waste gas and low-pressure waste gas. The high-pressure mixed gas and the low-pressure mixed gas are nitrogen mixed gas (nitrogen waste gas) rich in the same solvent.

When high-pressure and low-pressure waste gas share one collecting pipe, firstly, high-pressure waste gas can be mixed into low-pressure waste gas, and material mixing process accidents can happen; secondly, low-pressure waste gas can not enter the high-pressure waste gas pipe, so that gas is blocked, and low-pressure gas equipment cannot be normally used. Therefore, the waste gas with two pressures needs to be classified, transported and collected according to the pressure (namely, pressure) and humidity.

And S200, mixing and collecting gas, namely mixing the high-pressure waste gas and the low-pressure waste gas treated in the step S100 (by using a certain device) to obtain mixed waste gas, realizing the balance of the waste gas with two pressures on speed and pressure, and ensuring the uniform gas flow in the next step during compression and pressurization. In the step, the mixed waste gas can not cause the problems of air holding, abnormal use of low-pressure equipment and the like.

And step S300, compressing and pressurizing, specifically, compressing and pressurizing the mixed exhaust gas mixed in the step S200.

The pressurization method for treating the waste gas containing the low-boiling-point solvent has better effect than the normal pressure: the recycling of the waste gas containing the organic solvent firstly requires the removal of the solvent, but when the solvent is removed by normal-pressure low-temperature condensation, the effect of removing the high-boiling-point solvent can be achieved; the effect of removing the low boiling point solvent is poor, and the effect of removing the solvent can be improved by adopting pressure condensation.

Taking waste nitrogen from pharmaceutical factories as an example (acetone is taken as an example as a solvent in nitrogen), for example, when the partial pressure of acetone gas in the waste nitrogen is 5160pa, the liquid can be separated out only by cooling to-10 ℃ at normal pressure, and the liquid is compressed to 0.5MPa (gauge pressure) and the partial pressure of acetone gas is 30960pa at 6 times of the compression. At this point, cooling to 25 ℃ allowed the liquid to precipitate. Conversely, when the pressure is reduced to 0.5MPa (gauge pressure) and the temperature is cooled to-2 ℃ (with liquid separated out), the saturated partial pressure of the acetone gas is 8000pa, and when the pressure is reduced to 0.3MPa (gauge pressure), the pressure is equivalent to expansion by 1.5 times, the saturated partial pressure of the acetone gas is 5333pa, which is equivalent to cooling to nearly-10 ℃; when the pressure was reduced to normal pressure, the pressure was expanded by 6 times, and the saturated partial pressure of acetone gas was 1333pa, which corresponds to cooling to-30 ℃ or lower. It can be seen that the removal of the low boiling point solvent from the off-gas by pressure condensation is better.

And S400, condensing, separating and dehumidifying, namely condensing the pressurized mixed waste gas in the step S300 to separate the gas in the mixed waste gas from the solvent. In the step, the gas and the solvent in the mixed waste gas are separated and respectively collected, so that the effect of nitrogen dehumidification is achieved.

And S500, depressurizing for recycling, namely depressurizing the separated gas, separating the gas into two gases, namely high-pressure gas and low-pressure gas, and enabling the high-pressure gas and the low-pressure gas to respectively flow back into the high-pressure gas utilization equipment and the low-pressure gas utilization equipment. So far, the recycling of the waste gas with two different pressures is completed.

This gaseous recovery cyclic utilization technology, compared with the prior art, carry out gas classification earlier through the waste nitrogen gas with different pressures, carry out gas mixture collection again, later carry out compression pressure boost and condensation separation dehumidification to the mixed waste gas after mixing, thereby gas and solvent separation in the mixed waste gas, at last the gas after separating the solvent obtains high-pressure gas and low-pressure gas through the pressure reduction separation again, realize the cyclic recovery utilization of the waste gas of multiple different pressures, the waste nitrogen gas cyclic utilization demand of different pressures is handled simultaneously for sharing one set of system provides the technology and guides, the implementation that makes the waste nitrogen gas cyclic utilization of different pressures becomes possible.

As a specific implementation manner of the process applied to the nitrogen recycling system provided by the present invention, the gas classification of step S100 further includes the following operations: carry out preliminary cooling and gas-liquid separation to high-pressure waste gas, obtain the dry waste gas of high pressure after preliminary decompression, dehumidification, this operation is located and classifies the useless nitrogen pressure force, divide into high-pressure waste gas and low pressure waste gas to after separately carrying high-pressure waste gas and low pressure waste gas, actually carry out preliminary cooling and gas-liquid separation to high-pressure waste gas and also can think to going on in carrying high-pressure waste gas. Carry out primary cooling and gas-liquid separation (being the primary separation of gas and solvent) to high-pressure waste gas, can step down high-pressure waste gas and reduce humidity, the reinforcing removes the solvent effect, and subsequent step S200 gas mixture is collected and is just mixed the high-pressure waste gas and the low pressure waste gas after preliminary decompression, dehumidification, can effectively reduce the solvent gas partial pressure of the gas mixture of two kinds of gas mixtures like this to do benefit to the mixture of two kinds of different pressure gases.

As a specific embodiment of the process applied to the nitrogen recycling system, the step S300 of compressing and pressurizing further includes the following operations: the solvent condensed and separated in step S400 is used to cool the mixed gas mixed in the gas mixture collection in step S200. It should be understood that the cooling operation should be performed in synchronization with the operation of "compressing and pressurizing the mixed exhaust gas", that is, the cooling operation should be performed while compressing and pressurizing the mixed exhaust gas.

The compression and pressurization process is a heating process, a common compressor is adopted, the exhaust temperature is generally high (up to 70-80 ℃), the waste nitrogen contains a large amount of low-boiling-point solvent, and high-temperature and high-pressure exhaust has great potential safety hazard. Therefore, a liquid ring compressor is adopted for pressurization operation, and cooling fluid is introduced into the liquid ring compressor to compress and pressurize the side for cooling. But the cooling fluid cannot be a gas nor other liquid because the mixed exhaust gas may be flushed with more impurities. In order to introduce the solvent condensed and separated in the step S400, the solvent has the same component as that of the solvent in the mixed waste gas, so that no more waste gas is brought, and meanwhile, the solvent cooled and separated in the step S400 has lower temperature, so that the mixed gas in the liquid ring compressor can be cooled, and the exhaust temperature is controlled within 30 ℃ (lower than the boiling point of the solvent), so that the safe operation of the compressor is ensured.

As a specific embodiment of the process applied to the nitrogen recycling system, the nitrogen recycling system further comprises the steps before the step S500 of depressurization and recycling and after the step S400 of condensation and separation:

in step S410, the temperature of the gas is raised, specifically, the gas condensed and separated in step S400 is subjected to a temperature raising operation. Because the gas temperature after the condensation and separation in the step S400 is low, and the gas is required to be at normal temperature or high temperature in most cases, the gas after the condensation, separation and dehumidification in the step S400 needs to be heated and then decompressed for reuse, so that the relative humidity in the supplied gas is reduced, and the drying and moisture absorption capacity of the nitrogen is recovered.

Optionally, the step S410 of heating the gas is to heat the gas after the condensation, separation and dehumidification by using the compression heat generated in the step S300 of compression and pressurization.

Referring to fig. 1 to fig. 4, the nitrogen recycling system provided by the present invention is now described, which is used to process nitrogen with different pressures at the same time, and the gas recycling process in the above embodiment is applied, or the gas recycling process in the above embodiment needs to be implemented by the nitrogen recycling system provided by the embodiment of the present invention.

The embodiment of the utility model provides a nitrogen gas recovery cyclic utilization system includes gas classification transportation module, gas mixture collection module, compression pressure boost module, condensation separation module and step-down retrieval and utilization module.

The gas classification and transportation module is used for classifying the pressing force of the high-pressure mixed gas and the low-pressure mixed gas, and dividing the high-pressure mixed gas and the low-pressure mixed gas into high-pressure waste gas and low-pressure waste gas to be respectively conveyed. The gas classification transportation module specifically implements the operation of gas classification transportation in step S100.

And the gas mixing and collecting module is used for mixing and collecting the high-pressure waste gas and the low-pressure waste gas. The gas mixing and collecting module specifically realizes the operation of gas mixing and collecting in the step S200.

And the compression and pressurization module is used for compressing and pressurizing the mixed waste gas mixed and collected by the gas mixing and collecting module. The compression and pressurization module specifically realizes the operation of compression and pressurization in the step S300.

And the condensation separation module is used for condensing the mixed waste gas pressurized by the compression pressurization module so as to separate the gas in the mixed waste gas from the solvent. The condensation and separation module implements the condensation, separation, and dehumidification operation of step 400.

And the pressure reduction recycling module is used for reducing pressure and separating the gas separated by the condensation separation module into high-pressure gas and low-pressure gas, and conveying the high-pressure gas and the low-pressure gas to flow into high-pressure gas equipment and low-pressure gas equipment respectively. The step-down recycling module specifically realizes the step-down recycling operation in the step 500.

The embodiment of the utility model provides a nitrogen gas recovery cyclic utilization system, compared with the prior art, realize carrying out gas classification and transportation earlier with the waste nitrogen gas of different pressures through setting up gas classification transportation module, it realizes carrying out gas mixing collection to the waste nitrogen gas of different pressures to set up gas mixing collection module, it realizes compressing pressure boost and condensation separation to the mixed waste gas after mixing to set up compression pressure boost module and condensation separation module, realize the step-down separation through setting up step-down retrieval and utilization module at last and obtain high-pressure gas and low-pressure gas, finally realize the cyclic recycle of the waste nitrogen gas of multiple different pressures on one set of system, practice thrift the cost of recovery.

Referring to fig. 1 and fig. 2, as a specific embodiment of the nitrogen recycling system provided by the present invention, the gas classification transportation module includes: a high-pressure mixed gas conveying passage 1, a low-pressure mixed gas conveying passage 2, a first condenser 5 and a first gas-liquid separator 6.

The two ends of the high-pressure mixed gas conveying channel 1 are respectively communicated with a high-pressure gas device and a gas mixing and collecting module; two ends of the low-pressure mixed gas conveying channel 2 are respectively communicated with the low-pressure gas equipment and the gas mixing and collecting module. The high-pressure mixed gas conveying channel 1 and the low-pressure mixed gas conveying channel 2 are used for conveying the classified high-pressure mixed gas and low-pressure mixed gas respectively.

The first condenser 5 is connected in series in the high-pressure mixed gas conveying channel 1 and is used for cooling the high-pressure mixed gas firstly; the first gas-liquid separator 6 is also connected in series to the high-pressure mixed gas delivery passage 1 and located after the first condenser 5 in the flow direction of the high-pressure mixed gas, and is used for performing a preliminary separation operation of gas and solvent on the high-pressure mixed gas. The operation steps of cooling the high-pressure wet waste gas and separating gas from liquid to obtain depressurized dry waste gas are realized in the first condenser 5 and the first gas-liquid separator 6.

Referring to fig. 1 and 2, as a specific implementation manner of the nitrogen recycling system provided by the present invention, the gas mixing and collecting module includes an injector 7, the injector 7 has a first inlet of the injector, a second inlet of the injector, and an outlet of the injector, the first inlet of the injector and the second inlet of the injector are respectively conducted with the low-pressure mixed gas conveying passage 2 and the high-pressure mixed gas conveying passage 1, and the outlet of the injector is conducted with the compression and pressurization module. The ejector 7 can be an ejector pump in the prior art, can realize the mixing of high-pressure gas and low-pressure gas, avoids the mutual influence of high pressure and low pressure, realizes the balance of the speed and pressure of mixed gas, and ensures the uniformity of gas flow entering the compressor; the ejector has a supercharging effect on low-pressure gas, and the working efficiency of the compressor is improved.

Referring to fig. 1 and 2, as a specific embodiment of the nitrogen recycling system provided by the present invention, a first check valve 20 and a second check valve 21 are respectively disposed on the low-pressure mixed gas conveying passage 2 and the high-pressure mixed gas conveying passage 1 to prevent backflow of the gas when the exhaust gas is mixed.

Please refer to fig. 1 and fig. 3, as a specific embodiment of the nitrogen recycling system provided by the present invention, the condensation separation module includes a second condenser 9 for condensing the pressurized mixed gas and a second gas-liquid separator 10 for separating gas and liquid from the mixed gas cooled by the second condenser 9, and the gas outlet of the second gas-liquid separator 10 is communicated with the pressure reduction recycling module. The air inlet of the second gas-liquid separator 10 is communicated with the air outlet of the second condenser 9.

As a specific implementation mode of the nitrogen recovery and cyclic utilization system, the second condenser 9 adopts the split plate shell type heat exchanger, and nitrogen gas walks the shell side, and the pressure drop is less than or equal to 2kpa (is shell and tube heat exchanger 1/20), and equipment area is little, the removable easy maintenance in later stage.

Please refer to fig. 1, fig. 2 and fig. 3, as the utility model provides a nitrogen gas recovery cyclic utilization system's a specific implementation, compression and pressurization module includes compressor 8, compressor 8 has the low pressure air inlet, high pressure gas outlet and solvent inlet, the low pressure air inlet communicates with gas mixture collection module (specifically is the sprayer export), high pressure gas outlet communicates with second condenser 9, the solvent inlet communicates with second vapour and liquid separator 10's liquid outlet, the low temperature separation solvent that second vapour and liquid separator 10 collected can flow into in the compressor 8 to cooling to the mist in the compressor 8. The hardware and connection relationship provided by this embodiment can realize the operation of "cooling the mixed gas after mixing by using the solvent after condensation and separation".

As a specific implementation manner of the nitrogen recycling system, the compressor 8 is a liquid ring compressor, and it can use the same solvent as the compressor cooling liquid, and control the exhaust temperature within 30 ℃ (lower than the boiling point of the solvent), thereby ensuring the safe operation of the compressor 8. In addition, the liquid ring compressor is adopted for pressurization, and the exhaust temperature is controlled to be within 35 ℃ (lower than the boiling point of the solvent) and is safer than other types of compressors (the exhaust temperature is as high as 70-80 ℃).

Referring to fig. 1, fig. 3 and fig. 4, as a specific embodiment of the nitrogen recycling system provided by the present invention, the condensation separation module further includes a heat exchanger 11, and the heat exchanger 11 includes a heat exchange box 1102 and a heat pipe 1101 provided with a working fluid. The heat exchange box body 1102 is internally provided with a condensation cavity and an evaporation cavity which are not communicated with each other, the heat exchange tube 1101 comprises a condensation section 11011 and an evaporation section 11012 communicated with the condensation section 11011, the condensation section 11011 is arranged in the condensation cavity, and the evaporation section 11012 is arranged in the evaporation cavity.

The evaporation cavity is respectively communicated with the compression pressurization module (specifically, a high-pressure air outlet or an air outlet of the third gas-liquid separator 12) and an air inlet of the second condenser 9, and the condensation cavity is respectively communicated with an air outlet of the second gas-liquid separator 10 and the pressure reduction recycling module. The working liquid flows from the evaporation section 11012 to the condensation section 11011 in the cavity of the heat pipe 1101, so that the pressurized mixed gas is cooled in the evaporation cavity, and the gas separated by the second gas-liquid separator 10 is heated in the condensation cavity. Heat pipe 1101 is the prior art, and has a wick structure in its material, when one end (i.e., evaporation section 11012) of heat pipe 1101 is heated, the working fluid evaporates and vaporizes, the vapor flows to the other end under a slight pressure difference to release heat and condense into liquid, and the liquid flows back to evaporation section 11012 along the porous material (i.e., wick structure) by the action of capillary force. This cycle is repeated, and heat is transferred from one end of the heat pipe 1101 to the other end.

The heat exchanger 11 can perform the operation of "heating the gas and performing the heating operation on the separated gas". The working liquid evaporates and absorbs heat in the evaporation section 11012 and enters the condensation section 11011 to release heat and condense under the pushing of small pressure difference, and the consumption of cooling water and steam can be reduced simultaneously under the condition of not consuming external power in the heat exchanger 11, so that the aim of reducing the production cost is fulfilled. Working liquid in a heat pipe 1101 of the heat exchanger 11 is taken as a heat exchange medium to participate in twice heat exchange, so that the cold quantity (mainly the second condenser 9) and the heat quantity (mainly the refrigerant in the heat exchanger 11) input of the whole system are saved.

Please refer to fig. 1 and fig. 3, as a specific embodiment of the nitrogen recycling system provided by the present invention, the condensation separation module further includes a third gas-liquid separator 12, an air inlet of the third gas-liquid separator 12 is communicated with the high pressure air outlet, an air outlet of the third gas-liquid separator 12 is communicated with the second condenser 10 (or the evaporation cavity of the heat exchanger 11), a liquid inlet of the third gas-liquid separator 12 is communicated with a liquid outlet of the second gas-liquid separator 10, and a liquid outlet of the third gas-liquid separator 12 is communicated with the solvent liquid inlet.

The third gas-liquid separator 12 is further provided with an overflow pipeline 13, a second drain valve 23 is arranged in the overflow pipeline 13, the third gas-liquid separator and (the inner cavity of) the compressor 8 form a communicating vessel structure, and the liquid level of the solvent in the third gas-liquid separator 12 is equal to the liquid level of the solvent in the compressor 8 in height. By adopting the structure, the liquid level of the solvent in the third gas-liquid separator 12 and the liquid level of the solvent in the compressor are always equal in height, and the liquid shortage phenomenon of the compressor 8 is avoided by means of a physical means rather than an electronic sensor, so that the structure is more reliable. The exhaust gas from the compressor 8 entering the third gas-liquid separator 12 contains a large amount of solvent to ensure that the liquid level does not drop, and the excess solvent is discharged through the overflow line 13 of the third gas-liquid separator 12 without a high liquid level.

Referring to fig. 1 and 3, as a specific embodiment of the nitrogen recycling system provided by the present invention, a third condenser 22 is disposed between the liquid outlet of the third gas-liquid separator 12 and the solvent inlet of the compressor 8, so as to further cool the solvent flowing into the compressor 8.

Referring to fig. 1 and fig. 3, as a specific embodiment of the nitrogen recycling system provided by the present invention, a liquid inlet of the third gas-liquid separator 12 is communicated with a liquid outlet of the second gas-liquid separator 10 through a U-shaped pipeline 14, so as to increase the gas-liquid separation effect; on the other hand, the short circuit of the air flow can be avoided through the liquid seal.

Referring to fig. 1, as a specific implementation manner of the nitrogen recycling system provided by the present invention, the pressure-reducing recycling module includes: a high-pressure gas return passage 15, a low-pressure gas return passage 16, a first pressure reducing valve 17, and a second pressure reducing valve 18.

Wherein, two ends of the high-pressure gas returning channel 15 are respectively communicated with the high-pressure gas equipment and the condensation separation module; two ends of the low-pressure gas returning channel 16 are respectively communicated with low-pressure gas equipment and the condensation separation module; the first pressure reducing valve 17 is connected in series in the high-pressure gas returning channel 15 and is used for reducing the pressure of the gas separated by the condensation separation module into high-pressure gas; and the second pressure reducing valve 18 is connected in series in the low-pressure gas return channel 16 and is used for reducing the pressure of the gas separated by the condensation separation module into low-pressure gas.

As a specific implementation way of the nitrogen gas recycling system, in order to realize the multi-operating mode automatic control design of this system, the embodiment of the utility model provides a nitrogen gas recycling system still includes control module, control module and 8 electric connection of compressor to control opening of compressor 8 and stop.

Referring to fig. 1 and 2, as a specific embodiment of the nitrogen recycling system provided by the present invention, the gas classification module further includes a pressure compensation gas conveying channel 3 and a first pressure regulating valve 4 connected in series to the pressure compensation gas conveying channel 3, one end of the pressure compensation gas conveying channel 3 is communicated with the high-pressure gas source, the other end of the pressure compensation gas conveying channel 3 is communicated with the high-pressure mixed gas conveying channel 1, the first pressure regulating valve 4 can be a gas pressure reducing valve structure, and the first pressure regulating valve 4 is actuated by receiving a signal of the control module.

As a specific implementation manner of the nitrogen gas recycling system, the low pressure air inlet of compressor 8 is equipped with first pressure sensor, first pressure sensor and control module electric connection, and first pressure sensor can the pressure of real time monitoring low pressure air inlet, and when the pressure of the low pressure air inlet of compressor 8 was less than certain pressure value, control module will accuse control compressor 8 and shut down to avoid the evacuation operation to damage compressor 8.

The high pressure gas outlet of compressor 8 is equipped with second pressure sensor, and second pressure sensor and control module electric connection, the pressure of second pressure sensor high pressure gas outlet can real time monitoring, and when the pressure of the high pressure gas outlet of compressor 8 was greater than certain pressure value, control module will control compressor 8 and shut down.

As a specific embodiment of the nitrogen recycling system provided by the present invention, the insufficient flow of the solvent circulation fluid of the compressor 8 is a main cause of damage to the compressor 8, and in order to avoid flow break or adverse inlet/outlet (i.e. the pressure of the high pressure gas outlet is lower than that of the low pressure gas inlet, which causes no working fluid in the compressor cavity), a flow sensor is specially installed on the pipeline between the compressor 8 and the third condenser 22, so as to monitor the solvent inflow flow of the solvent inlet of the compressor 8; a level sensor for monitoring the solvent level in the third gas-liquid separator 12 is also installed in the third gas-liquid separator 12 to monitor the liquid level in the third gas-liquid separator 12 (i.e., to monitor the solvent liquid level in the compressor 8). The liquid level sensor and the flow sensor are respectively electrically connected with the control module.

When the liquid level in the third gas-liquid separator 12 is lower than the set height value or the flow sensor detects that the flow is smaller than the set flow value, the control module controls the compressor 8 to stop.

As a specific implementation manner of the nitrogen recovery cyclic utilization system, first relief pressure valve 17, second relief pressure valve 18 and first air-vent valve 4 are automatically controlled pneumatic type relief pressure valve structure, and it can be convenient for adjust outlet pressure, first relief pressure valve 17, second relief pressure valve 18 and first air-vent valve 4 respectively with control module electric connection, the control module of being convenient for carries out each valve outlet pressure's adjustment control.

As a specific implementation manner of the nitrogen recycling system, the adjusting function of the control module before the compressor 8 is shut down is added to the control function of the compressor, and the shut down is avoided as much as possible by pre-adjustment. In the aforementioned "low-flow shutdown of the compressor working fluid", the solvent flow rate is mainly determined by the pressure difference between the low-pressure inlet and the high-pressure outlet of the compressor, and when the inlet-outlet pressure difference (i.e., the pressure difference between the low-pressure inlet and the high-pressure outlet) is low, the low flow rate is caused. Therefore, when the low-flow alarm shutdown is designed, a measure for pre-adjusting the pressure difference between the inlet and the outlet needs to be designed to avoid the shutdown as much as possible:

firstly, the start and stop of the first pressure regulating valve 4 are controlled by an inlet-outlet pressure difference signal, and when the inlet-outlet pressure difference is smaller than a certain value, the control module gives a signal to the first pressure regulating valve 4 to enable the first pressure regulating valve 4 to act. Meanwhile, the pressure compensation gas conveying channel 3 is also connected with a compensation pressure limiting valve 26 in series, and the compensation pressure limiting valve 26 is designed to control the highest pressure of the nitrogen supplement because the opening of the first pressure regulating valve 4 is too large or the inlet pressure is high, and the working fluid is stopped at low flow rate when the pressure difference between the inlet and the outlet is too small. The compensating pressure limiting valve 26 is a valve for controlling the highest gas pressure in the pipeline, and can be an overflow valve or the like.

Secondly, when the gas consumption is too large and the pressure of the gas end is reduced too much under special working conditions such as cleaning gas equipment, if the first pressure reducing valve 17 or the second pressure reducing valve 18 is continuously opened, the pressure of the high-pressure gas outlet of the compressor 8 is inevitably too low (the pressure difference of the inlet and the outlet is too small, the pressure of the high-pressure gas outlet is lower than the pressure of the low-pressure gas inlet under extreme conditions, so that the counter pressure difference occurs, and no working fluid flows into the compressor 8). Generally, when the pressure of the gas end is reduced a lot, the first pressure reducing valve 17 or the second pressure reducing valve 18 is opened first according to the normal self-control program design to ensure that the gas equipment is used, but the pressure of the high-pressure gas outlet of the compressor 8 is reduced along with the pressure after the first pressure reducing valve 17 or the second pressure reducing valve 18 is opened, if the opening degree is not limited, the pressure difference of the inlet and the outlet of the compressor 8 is too small after the opening degree is increased to a certain opening degree. The pressure difference between the inlet and the outlet of the compressor 8 is the power for the circulation of the cooling liquid of the compressor, and the compressor 8 can be damaged due to the insufficient circulation amount of the cooling liquid of the compressor caused by too small pressure difference.

When the abnormal condition occurs, the use of the gas using equipment is ensured to be moved back to the second position, the compressor 8 is ensured not to be damaged and to be lifted to the first position, the opening degree of the first reducing valve 17 or the second reducing valve 18 is limited at the moment, when the abnormal condition occurs, the gas using equipment is actually in an abnormal production state, and the production loss is generally not caused by limiting the opening degree of the first reducing valve 17 or the second reducing valve 18. Limiting the maximum opening degree of the second reducing valve 18 when the gas used by the low-pressure gas using equipment 25 is abnormal (judged by a flow meter); the opening degree of the first pressure reducing valve 17 is restricted when the gas usage of the high-pressure gas usage equipment 24 is abnormal (determined by the flow meter).

Two control strategies need to be specifically designed to avoid the condition that the pressure difference between the inlet and the outlet of the compressor 8 is too small:

A. a lowest value of the pressure difference between the inlet and the outlet is set in a control strategy, and reverse regulation is adopted under the condition that the pressure difference between the inlet and the outlet is close to or equal to the lowest value, namely, the pressure of gas equipment for inlet gas is not ensured, and only the pressure of a high-pressure gas outlet of the compressor 8 is ensured (so that the pressure difference between the inlet and the outlet is ensured to avoid shutdown). In this case, the first pressure reducing valve 17 or the second pressure reducing valve 18 is closed even if the pressure of the gas-consuming equipment is lowered.

B. In the control strategy, only when the pressure difference between the inlet and the outlet is larger than the minimum value, the first pressure reducing valve 17 or the second pressure reducing valve 18 is operated in the positive direction, so that the pressure of the inlet equipment is ensured.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims (9)

1. Nitrogen gas recovery cyclic utilization system for handle the nitrogen gas of different pressures simultaneously, its characterized in that includes:

the gas classification and transportation module is used for separately conveying the classified high-pressure waste gas and low-pressure waste gas;

the gas mixing and collecting module is used for mixing and collecting the high-pressure waste gas and the low-pressure waste gas;

the compression and pressurization module is used for carrying out compression and pressurization treatment on the mixed waste gas mixed and collected by the gas mixing and collecting module;

the condensation separation module is used for condensing the mixed waste gas pressurized by the compression pressurization module to separate gas in the mixed waste gas from a solvent; and

and the pressure reduction recycling module is used for reducing pressure and separating the gas separated by the condensation separation module into high-pressure gas and low-pressure gas, and conveying the high-pressure gas and the low-pressure gas to flow into high-pressure gas equipment and low-pressure gas equipment respectively.

2. The nitrogen recovery and recycle system of claim 1, wherein the gas classification module comprises:

the two ends of the high-pressure mixed gas conveying channel are respectively communicated with a high-pressure gas device and the gas mixing and collecting module;

the two ends of the low-pressure mixed gas conveying channel are respectively communicated with a low-pressure gas device and the gas mixing and collecting module;

the first condenser is connected in series with the high-pressure mixed gas conveying channel and is used for cooling the high-pressure mixed gas; and

and the first gas-liquid separator is connected in series with the high-pressure mixed gas conveying channel, is positioned behind the first condenser and is used for performing primary separation operation of gas and solvent on the high-pressure mixed gas.

3. The nitrogen recycling system of claim 2, wherein the gas classification module further comprises a pressure compensation gas delivery channel and a first pressure regulating valve connected in series to the pressure compensation gas delivery channel, the pressure compensation gas delivery channel is in communication with the high-pressure mixed gas delivery channel, and the first pressure regulating valve controls the gas pressure in the pressure compensation gas delivery channel by receiving the outlet gas pressure information of the gas mixture collection module.

4. The nitrogen recycle system of claim 2 wherein the gas mixture collection module comprises an ejector having an ejector first inlet, an ejector second inlet, and an ejector outlet, the ejector first inlet and the ejector second inlet in communication with the low pressure mixed gas delivery passage and the high pressure mixed gas delivery passage, respectively, the ejector outlet in communication with the compression pressurization module.

5. The nitrogen recycling system of any one of claims 1 to 4, wherein the condensation separation module comprises a second condenser for condensing the pressurized mixed gas and a second gas-liquid separator for gas-liquid separating the mixed gas cooled by the second condenser, and a gas outlet of the second gas-liquid separator is communicated with the pressure reduction and reuse module.

6. The nitrogen recycling system of claim 5, wherein the compression and pressurization module comprises a compressor, the compressor is a liquid ring compressor, the compressor has a low pressure gas inlet, a high pressure gas outlet, and a solvent inlet, the low pressure gas inlet is in communication with the gas mixture collection module, the high pressure gas outlet is in communication with the second condenser, and the solvent inlet is in communication with a liquid outlet of the second gas-liquid separator.

7. The nitrogen recycling system of claim 6, wherein the condensation separation module further comprises a third gas-liquid separator, an air inlet of the third gas-liquid separator is communicated with the high-pressure air outlet, an air outlet of the third gas-liquid separator is communicated with the second condenser, an liquid inlet of the third gas-liquid separator is communicated with a liquid outlet of the second gas-liquid separator, and a liquid outlet of the third gas-liquid separator is communicated with the solvent liquid inlet;

the third gas-liquid separator is also provided with an overflow pipeline, the third gas-liquid separator and the compressor form a communicating vessel structure, and the liquid level of the solvent in the third gas-liquid separator is as high as the liquid level of the solvent in the compressor.

8. The nitrogen recycling system of claim 7, wherein the condensation separation module further comprises a heat exchanger, the heat exchanger comprises a heat exchange box body and a heat pipe provided with working fluid, the heat exchange box body is provided with a condensation chamber and an evaporation chamber which are not communicated with each other, the heat pipe comprises a condensation section and an evaporation section communicated with the condensation section, the condensation section is arranged in the condensation chamber, the evaporation section is arranged in the evaporation chamber, the evaporation chamber is communicated with the gas outlet of the third gas-liquid separator and the second condenser respectively, and the condensation chamber is communicated with the second gas-liquid separator and the pressure reduction and reuse module respectively;

the working liquid flows from the evaporation section to the condensation section in the heat pipe, the pressurized mixed gas is cooled in the evaporation cavity, and the gas separated by the second gas-liquid separator is heated in the condensation cavity.

9. The nitrogen recovery and recycle system of any one of claims 1 to 4, wherein the depressurization recycling module comprises:

the two ends of the high-pressure gas returning channel are respectively communicated with the high-pressure gas equipment and the condensation separation module;

the two ends of the low-pressure gas return channel are respectively communicated with the low-pressure gas equipment and the condensation separation module;

the first pressure reducing valve is connected in series in the high-pressure gas returning channel and is used for reducing the pressure of the gas separated by the condensation separation module into high-pressure gas; and

and the second pressure reducing valve is connected in the low-pressure gas returning channel in series and used for reducing the pressure of the gas separated by the condensation separation module into low-pressure gas.

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