CN209431758U - A kind of LNG factory drives recycling and reusing system of dropping a hint - Google Patents

Abstract

The utility model belongs to area of natural gas liquefaction, it drives to drop a hint recycling and reusing system more particularly to a kind of LNG factory, the gas pipeline of purification system is connect with ice chest, ice chest is connect by control valve with flash tank, the liquid outlet of flash tank connects LNG storage tank, and gas vent connection four-way is divided into three branches.The first branch installs blow valve；Second branch is connect with fuel gas using system, and heat exchanger and control valve are successively installed；Third bypass line is connect with regeneration gas pipe network, successively installs heat exchanger and control valve.When being driven using the utility model, the natural gas of early period is incorporated to regeneration gas pipe network after heating and recycles no longer directly by emptying of releasing flare；It makes full use of purified natural gas as heat source and Returning utilization, does not introduce new heat source to reduce energy consumption；Flow system is optimized, be used as fuel gas for natural gas or is incorporated to a variety of emptying measures of regeneration gas network collocation, has greatly ensured that system can be steadily safely operated.

Description

A kind of LNG factory drives recycling and reusing system of dropping a hint

Technical field

The utility model belongs to area of natural gas liquefaction, and in particular to a kind of LNG factory drives recycling and reusing of dropping a hint System.

Background technique

It is found through investigation, in the LNG factory of the prior art, in liquefaction system start-of-run, most LNG works There is the phenomenon that natural gas vent in driving process in factory.LNG liquefaction system includes ice chest, flash tank；It liquefies in LNG factory In system startup procedure, firstly, gas phase cryogen is gradually introducing ice chest, when the temperature after ice chest J-T valve reaches -60 DEG C, need Branch emptying natural gas is set from the pipeline after flash tank, makes the natural gas flow in ice chest to help ice chest gradually to establish temperature Gradient.It as ice chest cooling capacity increases, according to the temperature after J-T valve, needs to be gradually increased natural gas vent, to reach cold and hot flat Weighing apparatus, when the inlet temperature of flash tank reaches -140 DEG C or so, can just close natural gas vent valve.It drives successfully normal raw Postpartum, the hydrogen and portion of natural gas flashed off in flash tank do fuel gas after heat exchanger heats.It is put according to multiple driving The statistics of sky amount, natural gas vent amount is about 20000Nm in LNG factory liquefaction system startup procedure³Left and right causes a large amount of Energy waste and driving cost increase.

Therefore, it is necessary to improve liquefaction system, the emptying amount that LNG factory liquefaction system is driven is reduced.

Utility model content

The utility model aim is: in view of the above problems, providing a kind of LNG factory and drives to drop a hint recycling again Using process system, when solving the driving of existing LNG factory liquefaction system, the excessive problem of natural gas vent amount optimizes simultaneously Liquefaction system reduces energy waste on the whole, reduces driving cost.

Technical scheme of the utility model is as follows:

A kind of LNG factory drives recycling and reusing system of dropping a hint, and the gas pipeline and ice chest entrance of purification system connect It connects, ice chest outlet is connect by the first control valve with flash tank, and the liquid outlet of flash tank connects LNG storage tank, and gas vent connects Connect four-way；In other three bypass lines of the four-way, the first branch installs the first blow valve；Second branch and fuel gas benefit It is connected with system, First Heat Exchanger, the second control valve is successively installed；Third bypass line is connect with regeneration gas pipe network, is successively pacified Fill the second heat exchanger, third control valve.

Further, it includes A import, B import, the outlet A and the outlet B, the purification system that the ice chest, which is two-part ice chest, The gas pipeline of system is connect with A import leads to the outlet A, and the outlet A is other to be connected to the first knockout drum, the gas vent of the first knockout drum It is connect with ice chest B import and leads to the outlet B, the outlet B is connect by the first control valve with flash tank, the liquid outlet of the first knockout drum It is connect with heavy hydrocarbon storage tank.

Further, the thermal source inlet of the First Heat Exchanger and the gas pipeline of purification system connect, and described first Piping connection between the thermal source outlet of heat exchanger and the import and ice chest of the first knockout drum.Using purified natural gas as Heat source takes full advantage of existing raw material, while converging after exchanging heat with the condensed natural gas phase in one section of front end, makes full use of and drops Low energy consumption.

Further, the natural gas tube of branch and purification system is provided between second heat exchanger and regeneration gas pipe network Road connection.The natural gas of purification system has part to may be incorporated into regeneration gas pipe network.

Further, setting emptying branch is equipped with the second blow valve between the First Heat Exchanger and the second control valve, In system operation, when the gas flow as fuel gas after flash distillation is excessive, the emptying of the second blow valve may be selected.

Further, it is provided with emptying branch between second heat exchanger and regeneration gas pipe network and third emptying is installed Valve, when system start-up, and put regeneration gas pipe network gas flow it is excessive when, can be vented by third air defense valve.

Further, the thermal source inlet of second heat exchanger is connected with the one section outlet of refrigerant compressor, thermal source outlet Connect the second knockout drum.Cryogen provides cold source into ice chest after compressor boosts for natural gas liquefaction in the prior art, compresses Machine one section outlet is 120 degree without the temperature of water cooling, can be used as the heat source of the second heat exchanger, while the cryogen after cooling down can be with Reduce the energy consumption of latter step water cooling.

Further, the gas pipeline of purification system is connect with the recycling and reusing system again after the filter.

As the above scheme is adopted, compared with prior art, the utility model has the following beneficial effects: it is practical new using this When the liquefaction system of type is driven, the emptying natural gas for early period of driving passes through heating no longer directly by emptying of releasing flare After be incorporated to regeneration gas pipe network, before returning to dewatering system by the regeneration air compressor of rear end；Make full use of purified natural gas As heat source and Returning utilization, not introducing new heat source reduces energy consumption；Flow system is optimized, so that entire liquefaction system It is more reasonable to run, and is used as fuel gas for natural gas or is incorporated to a variety of emptying measures of regeneration gas network collocation, more Ensured that system can be steadily safely operated.

Detailed description of the invention

Fig. 1 is the process system schematic diagram of the utility model.

Marked in the figure: the first control valve of 1-, the first blow valve of 2-, the second control valve of 3-, 4- third control valve, 5- the 4th are controlled Valve processed, the 5th control valve of 6-, the second blow valve of 7-, 8- third blow valve, the 6th control valve of 9-, F-1 are filter, E-1 is cold Case, V-1 are the first knockout drum, V-2 is flash tank, E-2 is First Heat Exchanger, E-3 is the second heat exchanger, V-3 is the second separation Tank.

Specific embodiment

In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation Example, the present invention will be further described in detail.It should be appreciated that specific embodiment described herein is only used to explain The utility model is not used to limit the utility model.

The recycling and reusing system of dropping a hint as shown in Figure 1, a kind of LNG factory drives, the gas pipeline warp of purification system It crosses after filter F -1 and three branches is divided by threeway, wherein one connect with the A import of ice chest E-1, the outlet A of ice chest E-1 Side is connected to the first knockout drum V-1, and the gas vent of the first knockout drum V-1 is connect with the B import of ice chest E-1 leads to the outlet B, and B goes out Mouth is connect by the first control valve 1 with flash tank V-2, and the liquid outlet of the first knockout drum V-1 is connect with heavy hydrocarbon storage tank.Flash tank The liquid outlet of V-2 connects LNG storage tank, and gas vent connects four-way；In other three bypass lines of the four-way, first Road is installed by the first blow valve 2；Second branch is connect with fuel gas using system, and First Heat Exchanger E-2, the second control are successively installed Valve 3；Third bypass line is connect with regeneration gas pipe network, successively installs the second heat exchanger E-3, third control valve 4.

Article 2 branch of the gas pipeline of the purification system after filter F -1 is by being equipped with the 4th control The pipeline of valve 5 is connect with the heat source import of First Heat Exchanger E-2, and the thermal source outlet of the First Heat Exchanger E-2 is separated with first Piping connection between the import and ice chest E-1 of tank V-1.

Article 3 branch of the gas pipeline of the purification system after filter F -1 by the 5th control valve 6 with Piping connection between second heat exchanger E-3 and regeneration gas pipe network.

Further, setting emptying branch is equipped with the second emptying between the First Heat Exchanger E-2 and the second control valve 3 Valve 7.

Further, emptying branch is provided between the second heat exchanger E-3 and regeneration gas pipe network third is installed to put Empty valve 8.

Further, the one section outlet of the refrigerant compressor passes through the heat source of the 6th control valve 9 and the second heat exchanger E-3 Entrance is connected, and thermal source outlet connects the second knockout drum V-3.

The liquefaction system driving operational process of the utility model is as follows: being in Guangyuan LNG factory regeneration gas flow 4400Nm³/ h or so, before liquefaction system is driven, regeneration gas system has been operated normally, net by 6 control section of the 5th control valve Natural gas after change enters regeneration gas pipe network.When liquefaction system is driven, as cryogen introduces ice chest E-1, control thermal medium is Purified natural gas flow crosses ice chest E-1, and purified natural gas cools by first segment to -30 DEG C to -40 DEG C, laggard Enter the first knockout drum V-1, liquid is that heavy hydrocarbon enters heavy hydrocarbon storage tank, and gas is again introduced into ice chest E-1 and is cooled to -160 DEG C.Open the One control valve 1 and third control valve 4 allow natural gas to be incorporated to regeneration gas pipe network, meanwhile, the aperture of the 5th control valve 6 is controlled, is guaranteed Regeneration gas flow not excess.In addition, also can control the first blow valve 2 to carry out partially draining when gas discharge is excessive.

At the same time, the cryogen inlet that the second heat exchanger E-3 is controlled by the 6th control valve 9, so that being incorporated to regeneration The natural gas temperature of gas pipe network is 20-30 DEG C.The refrigerant temperature of the one section outlet of refrigerant compressor is 120 DEG C or so, due to cold Agent flux is much larger than the gas discharge for being incorporated to regeneration gas pipe network, so, the temperature into the natural gas of regeneration gas pipe network can be with It controls well.When the amount of natural gas that third control valve 4 controls is more than 4400Nm³When/h, the 5th control valve 6 is entirely at this time It closes, excess portion of natural gas can be vented by third blow valve 8.

The First Heat Exchanger E-2 is used as hydrogen-rich hot-air heater, during normal production, the hydrogen flashed off in flash tank V-2 Make fuel gas after First Heat Exchanger E-2 heating with portion of natural gas, heat source is provided by the natural gas of purification system, by the 4th Control valve controls the purified gas discharge as heat source.When the flow for being used as fuel gas is excessive, can be put by second Empty valve 7 reduces flow.As the front end for being incorporated to the first knockout drum V-1 after the purified natural gas cooling of heat source.

Repeatedly driving natural gas vent amount counts Guangyuan LNG factory liquefaction system, and each liquefaction system is driven, and natural gas is put Empty probably 4h or so, on an hourly basis averagely 5000Nm³It calculates, is driven using new process flow system, it is average to put less per hour Empty amount of natural gas is 4000N m³, it is 16000N m that emptying natural gas amount is lacked in each liquefaction system driving in total³, by natural at present 1.65 yuan/Nm of gas unit price³It calculates, each driving expense saves 26400 yuan, removes cold caused by the reflux of E-307 cryogen thermal medium Increased about 3200 yuan of agent power consumption of compressor, each driving expense saves 23200 yuan.By annual 5 calculating of driving, day is saved in year Right gas 80000Nm³, save about 116000 yuan of driving expense in year.

The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this Made any modifications, equivalent replacements, and improvements etc., should be included in the utility model within the spirit and principle of utility model Protection scope within.

Claims (8)

1. The recycling and reusing system of dropping a hint 1. a kind of LNG factory drives, it is characterised in that: the gas pipeline of purification system with it is cold Tank inlet connection, ice chest outlet are connect by the first control valve with flash tank, and the liquid outlet of flash tank connects LNG storage tank, gas Body outlet connection four-way；In other three bypass lines of the four-way, the first branch installs the first blow valve；Second branch with Fuel gas is connected using system, successively installs First Heat Exchanger, the second control valve；Third bypass line and regeneration gas pipe network connect It connects, the second heat exchanger, third control valve is successively installed.
2. 2. recycling and reusing system according to claim 1, it is characterised in that: the ice chest is that two-part ice chest includes A Import, B import, the outlet A and the outlet B, the gas pipeline of the purification system is connect with A import leads to the outlet A, and the outlet A is other It is connected to the first knockout drum, the gas vent of the first knockout drum is connect with ice chest B import leads to the outlet B, and the outlet B passes through the first control Valve is connect with flash tank, and the liquid outlet of the first knockout drum is connect with heavy hydrocarbon storage tank.
3. 3. recycling and reusing system according to claim 1, it is characterised in that: the thermal source inlet of the First Heat Exchanger with The gas pipeline of purification system connects, between the thermal source outlet of the First Heat Exchanger and the import and ice chest of the first knockout drum Piping connection.
4. 4. recycling and reusing system according to claim 1, it is characterised in that: second heat exchanger and regeneration gas pipe network Between be provided with the gas pipeline of branch and purification system and connect.
5. 5. recycling and reusing system according to claim 1-4, it is characterised in that: the First Heat Exchanger and Setting emptying branch is equipped with the second blow valve between two control valves.
6. 6. recycling and reusing system according to claim 5, it is characterised in that: second heat exchanger and regeneration gas pipe network Between be provided with emptying branch third blow valve is installed.
7. 7. recycling and reusing system according to claim 6, it is characterised in that: the thermal source inlet of second heat exchanger with The one section outlet of refrigerant compressor is connected, and thermal source outlet connects the second knockout drum.
8. 8. recycling and reusing system according to claim 7, it is characterised in that: the gas pipeline of purification system passed through It is connect again with the recycling and reusing system after filter.