CN219889340U - A nitrogen gas replacement system for gas station emergency evacuation - Google Patents

Abstract

The utility model relates to the technical field of emergency repair of gas transmission stations, and discloses a nitrogen replacement system for emergency emptying of a gas transmission station, wherein an emergency emptying pipeline of the gas transmission station comprises a high-pressure pipeline, a medium-pressure pipeline and a low-pressure pipeline, the emergency emptying pipeline comprises a compressor and a nitrogen generating device, the compressor is connected with the nitrogen generating device, the nitrogen generating device is connected with a nitrogen replacement pipe, and the nitrogen replacement pipe is connected with the high-pressure pipeline, the medium-pressure pipeline and the low-pressure pipeline; the nitrogen generating device comprises a freeze dryer, a molecular sieve filter and a nitrogen purity detector which are sequentially connected, so that the problems of complex nitrogen source supply operation and untimely supply when each pipeline of the gas transmission station is subjected to nitrogen replacement under the condition of emergency emptying of the existing gas transmission station are solved.

Description

A nitrogen gas replacement system for gas station emergency evacuation

Technical Field

The utility model relates to the technical field of emergency repair of gas transmission stations, in particular to a nitrogen replacement system for emergency emptying of a gas transmission station.

Background

The gas transmission station is a variety of operation stations which are built for pipeline transportation of natural gas or petroleum associated gas, the gas transmission station supplies fuel to vehicles and branch pipelines in the form of compressed natural gas, the gas in the natural gas pipeline is generally subjected to pre-purification treatment to remove sulfur and water in the gas, the pressure is compressed from 0.1-1.0 Mpa to 25.0Mpa by a compressor unit, and finally the gas is transported by a gas selling machine for vehicle gas transmission or injection into the branch pipelines.

When an emergency occurs in the gas station, the gas station needs to be immediately disconnected from the upstream pipeline and the downstream pipeline, and meanwhile, the emptying valve is opened, so that the accident source is timely salvaged after the natural gas in the pipeline of the gas station is emptied, the safety of the gas station is ensured, and meanwhile, after the natural gas in the gas station is emptied, nitrogen replacement is carried out on each pipeline in the station by utilizing inert gas nitrogen, so that the natural gas is completely emptied, the fire operation standard is achieved, and safety accidents such as explosion and the like caused by the natural gas during emergency repair are avoided.

At present, most of nitrogen replacement after emergency emptying of a gas transmission station adopts a mode of using a nitrogen cylinder to connect a pipeline and releasing nitrogen in the nitrogen cylinder to replace the nitrogen, however, the capacity of the nitrogen cylinder is limited, the number of the nitrogen cylinders required for carrying out one-time nitrogen replacement is large for the emergency emptying pipeline of the gas transmission station, and the nitrogen cylinders are required to be manually reconnected when each bottle of nitrogen replacement is used up, so that the rush-repair operation time is greatly increased; the large-scale domestic liquid nitrogen transport vehicle is not enough to match the emergency emptying requirements of all large gas transmission stations at present, and the liquid nitrogen vaporizer is large in volume and inconvenient to transport, and is difficult to arrive at the site in time for operation when the gas transmission stations need emergency emptying.

Disclosure of Invention

The utility model aims to provide a nitrogen replacement system for emergency emptying of a gas transmission station, which aims to solve the problems of complicated nitrogen source supply operation and untimely supply when each pipeline of the gas transmission station is subjected to nitrogen replacement under the condition of emergency emptying of the existing gas transmission station.

In order to achieve the above purpose, the utility model adopts the following technical scheme: the nitrogen replacement system comprises a high-pressure pipeline, a medium-pressure pipeline and a low-pressure pipeline, wherein the high-pressure pipeline, the medium-pressure pipeline and the low-pressure pipeline are arranged in the emergency emptying pipeline of the gas transmission station; the nitrogen generating device comprises a freeze dryer, a molecular sieve filter and a nitrogen purity detector which are connected in sequence.

The beneficial effect of this scheme is: the nitrogen generating device is connected with a high-pressure pipeline, a medium-pressure pipeline and a low-pressure pipeline in the gas transmission station, when nitrogen replacement is needed, the nitrogen generating device is started to directly purify nitrogen in air and directly send the purified nitrogen into each pipeline for nitrogen replacement, and the problems that in the prior art, the operation of supplying the nitrogen gas cylinder is complicated, the emergency repair time is influenced after emergency emptying, the emergency repair time is influenced due to the fact that the nitrogen supply is not timely in a liquid nitrogen vaporization mode are solved;

1. the nitrogen generating device obtains nitrogen from air, and the conditions that the nitrogen is not supplied enough and the nitrogen replacement is interrupted and needs to come again because the supply of nitrogen sources is insufficient in the nitrogen replacement process are avoided, so that the natural gas emergency emptying and rush repair operation requirements of the gas transmission station are further met;

2. the nitrogen purity detector in the nitrogen generating device monitors the purity of the output nitrogen so as to ensure that the system can reach the safety standard of the fire operation after nitrogen replacement;

3. the nitrogen generation device is arranged in a gas transmission field, when an emergency occurs, the nitrogen preparation operation can be started in the process of natural gas emptying, the nitrogen replacement can be performed at the first time of the nitrogen replacement, and the rush repair time is saved.

Preferably, the nitrogen generating device further comprises an air buffer tank and a nitrogen buffer tank, wherein the air buffer tank is arranged in front of the freeze dryer, the nitrogen buffer tank is arranged behind the molecular sieve filter, and the nitrogen purity detector is connected to the nitrogen buffer tank; a first filter is arranged between the freeze dryer and the air buffer tank, and a second filter is arranged between the freeze dryer and the molecular sieve filter.

The beneficial effect of this scheme is: filtering out impurities and water by a filter to improve the purity of the prepared nitrogen; the nitrogen is temporarily stored in the buffer tank between the nitrogen entering the gas transmission station, so that the stability of gas flow during the operation of the whole system is ensured, and the safety is ensured.

Preferably, the nitrogen generating device further comprises a thermometer and a pressure gauge, and the thermometer and the pressure gauge are sequentially connected behind the nitrogen buffer tank.

The beneficial effect of this scheme is: the thermometer and the pressure gauge can ensure that the temperature range of nitrogen output is between 5 and 55 ℃ and the pressure range of output is between 0.15 and 0.2MPa, so as to avoid the conditions of pipeline deformation and the like and ensure the stable output of nitrogen.

Preferably, the system further comprises a natural gas storage tank, wherein the natural gas storage tank is connected with the low-pressure pipeline, the compressor is a gas compressor, and the natural gas storage tank is connected with the gas compressor.

The beneficial effect of this scheme is: a part of natural gas to be emptied is input into the gas compressor, power is supplied to the gas compressor, the cost required by the operation of the nitrogen replacement system is reduced, a part of natural gas to be emptied is consumed, the time required by the whole gas transmission station for emptying the natural gas can be shortened, the rush repair time can be further shortened, and the requirement of emergency rush repair is met; the natural gas storage tank is arranged, so that the flow speed of the natural gas before entering the gas compressor becomes stable, the safety of the system in operation is ensured, and the natural gas stored in the natural gas storage tank can continuously provide power for the gas compressor after the natural gas is exhausted.

Preferably, a pressure reducing valve is arranged between the low-pressure pipeline and the natural gas storage tank.

The beneficial effect of this scheme is: the natural gas output by the low-pressure pipeline is subjected to depressurization treatment by the pressure valve so as to ensure the normal use of the gas compressor.

Preferably, the nitrogen replacement pipe is provided with a shut-off valve and a one-way valve.

The beneficial effect of this scheme is: the check valve can avoid the condition that nitrogen flows back due to the gradual increase of nitrogen in each pipeline in the gas transmission station in the nitrogen replacement process.

Preferably, the one-way valve is positioned at one end of the nitrogen replacement pipe near the high pressure pipe, the medium pressure pipe and the low pressure pipe.

The beneficial effect of this scheme is: the one-way valve is positioned at one end of the nitrogen replacement pipe, which is close to the high-pressure pipeline, the medium-pressure pipeline and the low-pressure pipeline, so that the path of nitrogen during backflow can be reduced, and the nitrogen can flow out to the outlet more smoothly, thereby improving the nitrogen replacement efficiency and shortening the nitrogen replacement time.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present utility model;

FIG. 2 is a schematic diagram of a nitrogen generating device according to the present utility model.

Detailed Description

The following is a further detailed description of the embodiments:

reference numerals in the drawings of the specification include: high-pressure piping 1, high-pressure relief valve 11, medium-pressure piping 2, medium-pressure relief valve 21, low-pressure piping 3, low-pressure relief valve 31, relief pipe 4, compressor 5, intake pipe 51, pressure regulating valve 52, natural gas tank 53, first valve 54, second valve 55, nitrogen generator 6, nitrogen replacement pipe 61, check valve 62, shut-off valve 63, air buffer tank 601, first filter 602, freeze dryer 603, second filter 604, molecular sieve filter 605, nitrogen buffer tank 606, nitrogen purity detector 607, pressure regulating valve 608, thermometer 609, pressure gauge 610, exhaust gas exhaust pipe 611.

Examples

An embodiment is substantially as shown in figures 1-2 and a nitrogen substitution system for emergency venting of a gas transfer station as shown in figure 1 includes a compressor 5 and a nitrogen generating device 6. Emergency emptying of a gas station includes three situations: high-pressure pipeline 1 is emptied, medium-pressure pipeline 2 is emptied and low-pressure pipeline 3 is emptied, wherein high-pressure pipeline 1 is usually emptied by a natural gas pressurizing compressor outlet for a gas transmission station, medium-pressure pipeline 2 is usually emptied by an in-out ESD trigger, an in-out filter is salvaged, a receiving and transmitting pipe cleaner is emptied, and low-pressure pipeline 3 is usually emptied by pollution discharge. When the emergency condition of the gas transmission station needs to be examined and repaired, the upstream gas transmission pipe and the downstream gas transmission pipe connected with the gas transmission station are cut off in time, then after the natural gas in all pipelines including high pressure, medium pressure and low pressure in the gas transmission station is exhausted in an emergency mode, the pipelines are replaced by nitrogen, and the residual natural gas is discharged, so that the requirement of fire operation is met, and secondary accidents are avoided. Because of the emergency emptying, the time is required to be shortened in the steps of natural gas emptying and nitrogen replacement, and the situations of interruption of nitrogen replacement, heavy head and the like are avoided.

As shown in fig. 1, a high-pressure pipeline 1, a medium-pressure pipeline 2 and a low-pressure pipeline 3 in the gas transmission station are all connected with a vertical blow-down pipe 4, the blow-down pipe 4 is an essential component of the gas transmission station, and is used as a safety measure for realizing the natural gas blow-down operation of the gas transmission station under various conditions, and the specific connection mode of the blow-down pipe 4 is as follows: the vent pipe 4 is connected with a vent main pipeline in a sealing way through a three-way connecting valve, the high-pressure pipeline 1, the medium-pressure pipeline 2 and the low-pressure pipeline 3 are communicated with the vent main pipeline in a sealing way in a parallel way, and the vent main pipeline is a stainless steel high-pressure seamless pipe and can bear gas with the pressure of more than 25.0 MPa. The high-pressure pipeline 1 and the blow-down pipe 4 are provided with a high-pressure blow-down valve 11, the medium-pressure pipeline 2 and the blow-down pipe 4 are provided with a medium-pressure blow-down valve 21, and the low-pressure pipeline 3 and the blow-down pipe 4 are provided with a low-pressure blow-down valve 31.

The air outlet end of the compressor 5 is connected with a nitrogen generating device 6. When the compressor 5 works, external air can be sucked into the compressor 5 to be compressed and pressurized, pressurized air is input into the nitrogen generating device 6 to be manufactured by nitrogen, the nitrogen generating device 6 is connected with the nitrogen replacing pipe 61, one end of the nitrogen replacing pipe 61, which is close to the gas transmission station, is provided with three branch pipes, and the three branch pipes are respectively communicated with the high-pressure pipeline 1, the medium-pressure pipeline 2 and the low-pressure pipeline 3 so as to simultaneously replace nitrogen for each pipe in the gas transmission station, thereby improving the nitrogen replacing efficiency and shortening the replacing time. The nitrogen replacement pipe 61 is provided with a cut-off valve 63 and a one-way valve 62, and the one-way valve 62 can avoid the condition that nitrogen flows back due to the gradual increase of nitrogen in each pipeline in the gas transmission station in the nitrogen replacement process; as shown in fig. 1, the check valve 62 is located at one end of the nitrogen replacement pipe 61 near the three branch pipes, so as to reduce the path of nitrogen during reflux, and make the nitrogen flow out to the outlet more smoothly, thereby improving the nitrogen replacement efficiency and shortening the nitrogen replacement time; the shutoff valve 63 was opened to introduce nitrogen gas prepared in the nitrogen gas generating apparatus 6 into each pipe of the gas transfer station, and nitrogen gas substitution was performed.

The compressor 5 is a gas compressor 5, as shown in fig. 1, an air inlet pipe 51 is arranged between an air inlet end of the compressor 5 and the low-pressure pipeline 3 for communication, and a specific connection mode of the air inlet pipe 51 is as follows: an exhaust connection port is reserved on the low-pressure pipeline 3 in advance, and in operation, the air inlet end of the compressor 5 is connected with the air outlet end of the air inlet pipe 51 through a flange, and then the air inlet end of the air inlet pipe 51 is connected with the air outlet connection port on the low-pressure pipeline 3 through a flange. The gas inlet pipe 51 is provided with a first valve 54, a pressure reducing valve, a natural gas storage tank 53 and a second valve 55, when the gas transmission station needs to be subjected to emergency emptying, part of natural gas to be emptied passes through the gas inlet pipe 51, is subjected to pressure reducing treatment by the pressure reducing valve, and is input into the gas compressor 5 to provide power for the gas compressor 5; the gas compressor 5 not only reduces the cost required by the nitrogen replacement system in operation, and consumes a part of natural gas to be emptied, but also shortens the time required by the whole gas transmission station to empty the natural gas, and can further shorten the rush repair time and meet the requirement of emergency rush repair. The natural gas storage tank 53 is arranged, so that the flow speed of the natural gas before entering the gas compressor 5 can be stabilized, the safety of the system in operation is ensured, and the natural gas stored in the natural gas storage tank 53 can continuously provide power for the operation of the gas compressor 5 after the natural gas is exhausted.

The nitrogen generating device 6 is installed in a region of the gas station facing away from the blow-down pipe 4, and as shown in fig. 2, an air buffer tank 601, a first filter 602, a freeze dryer 603, a second filter 604, a molecular sieve filter 605, a waste gas exhaust pipe 611, a nitrogen buffer tank 606, a nitrogen purity detector 607, a pressure regulating valve 52, a thermometer 609 and a pressure gauge 610 are connected in this order from left to right inside the nitrogen generating device 6 through pipes. The air buffer tank 601 is communicated with the air outlet end of the compressor 5 through a pipeline, when nitrogen is prepared, the compressor 5 compresses and pressurizes external air, the compressed air is temporarily stored in the air buffer tank 601 first so that the flow speed of the compressed air is stable, the compressed air is filtered by the first filter 602 to remove impurities and moisture, then enters the freeze dryer 603, the freeze dryer 603 cools the compressed air to 2-10 ℃, the dew point temperature of the moisture is reduced, the moisture in the air is condensed, and the moisture in the air is removed again, so that the purity of the finally output nitrogen is improved; then, the dehumidified and dried low-temperature compressed air enters a molecular sieve filter 605, and the molecular sieve filter 605 selectively adsorbs and blocks impurity molecules in the air and only passes through nitrogen by utilizing the characteristic that the molecular sieve has great difference on adsorption quantity of oxygen atoms and nitrogen atoms in a certain time, so that the aim of purifying and obtaining nitrogen in the air in high purity is fulfilled; the waste gas such as oxygen in the air is discharged from the waste exhaust pipe, nitrogen enters the nitrogen buffer tank 606 for temporary storage after passing through the molecular sieve filter 605, the stability of gas flow during operation of the whole nitrogen generating device 6 is ensured again, the nitrogen purity detector 607 detects the purity of the nitrogen in the nitrogen buffer tank 606, and when the concentration of the nitrogen is detected to be more than or equal to 99.9%, the cut-off valve 63 can be opened to replace the nitrogen in the gas transmission station.

And, on the valve at the end that high-pressure pipeline 1, middling pressure pipeline 2 and low pressure pipeline 3 kept away from nitrogen gas displacement tube 61 to and all be equipped with oxygen content detector on the blowdown total pipe, in the in-process that carries out nitrogen gas displacement, the valve at pipeline end is opened, and oxygen content detector detects the content of oxygen in the effluent gas in real time, and when all oxygen content detectors detected that the oxygen content in the effluent gas is less than 2%, indicate that nitrogen gas displacement is accomplished promptly, and the operational environment in the gas transmission station has reached construction fire safety standard. In addition, the thermometer 609 and the pressure gauge 610 can ensure that the temperature range of nitrogen output is between 5 and 55 ℃ and the pressure range of output is between 0.15 and 0.2MPa, so as to avoid the conditions of pipeline deformation and the like and ensure the stable output of nitrogen. The nitrogen in the air is purified by the nitrogen generating device 6 and then directly used by the nitrogen replacing tube 61, so that the problems of low nitrogen replacing efficiency and prolonged rush repair time caused by complex operation in a mode of continuously replacing a nitrogen bottle and providing a nitrogen source can be solved; meanwhile, the problems that nitrogen replacement is invalid and needs to be restarted and the nitrogen replacement efficiency is reduced due to the fact that the nitrogen source is unstable in supply and the nitrogen replacement operation is interrupted can be avoided.

The specific implementation process is as follows: when an emergency situation occurs in the gas transmission station and natural gas needs to be exhausted urgently, the gas inlet pipe 51 is communicated with the low-pressure pipeline 3 in the gas transmission station, then the high-pressure exhausting valve 11, the medium-pressure exhausting valve 21 and the low-pressure exhausting valve 31 are sequentially opened, and natural gas in the high-pressure pipeline 1, the medium-pressure pipeline 2 and the low-pressure pipeline 3 is exhausted through the exhausting pipe 4; meanwhile, in the process, part of natural gas in the low-pressure pipeline 3 passes through the gas inlet pipe 51, is depressurized by the depressurization valve and is temporarily stored in the natural gas storage tank 53.

When the natural gas discharged from the blow-down pipe 4 is slow and the blow-down is about to end, starting the gas compressor 5 and the nitrogen generating device 6 to start working, and when the nitrogen purity detector 607 detects that the purity of the nitrogen in the nitrogen buffer tank 606 reaches 99.9%, opening the cut-off valve 63, inputting the nitrogen into the high-pressure pipeline 1, the medium-pressure pipeline 2 and the low-pressure pipeline 3 through the nitrogen replacement pipe 61, and starting nitrogen replacement; when all oxygen content detectors in the system detect that the content of oxygen in the discharged replacement gas is less than 2%, the nitrogen replacement is finished, and the working environment in the gas transmission station reaches the construction fire safety standard.

Through installing one set of nitrogen generating device 6 in the gas transmission station, under the condition that the gas transmission station needs the natural gas of blowing out, carry out urgent repair, directly connect relevant device, starting drive can be with in the air continuous nitrogen gas high purity preparation obtains the back directly lets in each pipeline in the gas transmission station in, has improved the efficiency of nitrogen replacement, has reduced the complexity of operation to can also ensure the stable output of nitrogen, satisfy the operation requirement of salvaging.

The foregoing is merely exemplary of the present utility model, and specific technical solutions and/or features that are well known in the art have not been described in detail herein. It should be noted that, for those skilled in the art, several variations and modifications can be made without departing from the technical solution of the present utility model, and these should also be regarded as the protection scope of the present utility model, which does not affect the effect of the implementation of the present utility model and the practical applicability of the patent. The protection scope of the present utility model is subject to the content of the claims, and the description of the specific embodiments and the like in the specification can be used for explaining the content of the claims.

Claims (7)

1. A nitrogen gas replacement system for gas station emergency vent, gas station emergency vent pipeline includes high pressure pipeline, middling pressure pipeline and low pressure pipeline, its characterized in that: the device comprises a compressor and a nitrogen generating device, wherein the compressor is connected with the nitrogen generating device, the nitrogen generating device is connected with a nitrogen replacement pipe, and the nitrogen replacement pipe is connected with a high-pressure pipeline, a medium-pressure pipeline and a low-pressure pipeline; the nitrogen generating device comprises a freeze dryer, a molecular sieve filter and a nitrogen purity detector which are connected in sequence.

2. A nitrogen replacement system for emergency venting of a gas station as defined in claim 1, wherein: the nitrogen generating device further comprises an air buffer tank and a nitrogen buffer tank, wherein the air buffer tank is arranged in front of the freeze dryer, the nitrogen buffer tank is arranged behind the molecular sieve filter, and the nitrogen purity detector is connected to the nitrogen buffer tank; a first filter is arranged between the freeze dryer and the air buffer tank, and a second filter is arranged between the freeze dryer and the molecular sieve filter.

3. A nitrogen replacement system for emergency venting of a gas station as claimed in claim 2, wherein: the nitrogen generating device further comprises a thermometer and a pressure gauge, and the thermometer and the pressure gauge are sequentially connected behind the nitrogen buffer tank.

4. A nitrogen replacement system for emergency venting of a gas station according to claim 3, wherein: the natural gas storage tank is connected with the low-pressure pipeline, the compressor is a gas compressor, and the natural gas storage tank is connected with the gas compressor.

5. A nitrogen replacement system for emergency venting of a gas station as defined in claim 4 wherein: a pressure reducing valve is arranged between the low-pressure pipeline and the natural gas storage tank.

6. A nitrogen replacement system for emergency venting of a gas station as defined in claim 1, wherein: the nitrogen replacement pipe is provided with a cut-off valve and a one-way valve.

7. A nitrogen replacement system for emergency venting of a gas station as defined in claim 6 wherein: the one-way valve is positioned at one end of the nitrogen replacement pipe close to the high-pressure pipeline, the medium-pressure pipeline and the low-pressure pipeline.