The two differential energy-conservation liquefying plants of decompressor in natural gas transmission main line double loop
Technical field
The utility model relates to the natural gas transport technical field, the two differential energy-conservation liquefying plants of decompressor in particularly a kind of natural gas transmission main line double loop.
Background technology
Natural gas is a kind of gaseous state fossil fuel of mainly being made up of methane.It mainly is present in oil field and gas field, also has a small amount of from the coal seam.Do not have waste residue, waste water behind the combustion of natural gas and produce, compare coal, the oil equal energy source has safe in utilization, advantages such as calorific value is high, cleaning.
Natural gas has become the important energy source of Chinese Economy Development at present owing to its distinctive advantage, and domestic natural gas transmission trunk line pressure is 8.0-10.0Mpa, and after reducing pressure in the defeated station of trunk line each minute along the line, general post-decompression pressure is about 4.0Mpa.Handing over gas to give in this process of pipeline of user, pressure reduction has often wasted on the valve of regulator.The pressure reduction that has reaches 3.0-6.0Mpa, can obtain the liquefied fraction more than 10% through constant entropy expansion; The pressure reduction that has has only 1.5-3.0Mpa, and it is low to import and export pressure ratio, and less than 2.5, if adopt general single decompressor constant entropy expansion technology, liquefied fraction is lower.
Therefore, how importing and exporting under the low situation of pressure ratio, improving liquefied fraction, is the technical problem that those skilled in the art need to be resolved hurrily.
The utility model content
In view of this, the utility model provides a kind of natural gas transmission main line double loop two differential energy-conservation liquefying plants of decompressor, importing and exporting under the low situation of pressure ratio, improves liquefied fraction.
For realizing above-mentioned purpose, the utility model provides following technical scheme:
The two differential energy-conservation liquefying plants of decompressor in a kind of natural gas transmission main line double loop are used for the natural gas transmission main line, comprise being used for the pressure piping that is communicated with main pressure piping, and are used for the low pressure pipeline that is communicated with the natural valve of user station, also comprise:
Be communicated with said pressure piping and said low pressure pipeline respectively, and first order expander system that is in parallel and second level expander system;
The liquified natural gas stocking system parallelly connected with said second level expander system.
Preferably, in the two differential energy-conservation liquefying plants of decompressor in above-mentioned natural gas transmission main line double loop, also comprise the chopped-off head clarifier that is arranged between said first order expander system and second level expander system and the said pressure piping.
Preferably, in the two differential energy-conservation liquefying plants of decompressor in above-mentioned natural gas transmission main line double loop, said first order expander system comprises hot junction booster expansion turbine, main heat exchanger and crosses cold heat exchanger;
The expanding end import of said hot junction booster expansion turbine is connected with the outlet of said chopped-off head clarifier through said first internal pipeline;
The expanding end outlet of said hot junction booster expansion turbine links to each other with said main heat exchanger through second internal pipeline, and said main heat exchanger links to each other with the pressurized end import of said hot junction booster expansion turbine through the 3rd internal pipeline;
The pressurized end outlet of said hot junction booster expansion turbine links to each other with said low pressure pipeline through pipeline.
Preferably; In the two differential energy-conservation liquefying plants of decompressor in above-mentioned natural gas transmission main line double loop; Said second level expander system comprises cold junction booster expansion turbine, compressor and secondary stage purified device, and said secondary stage purified device is connected with said chopped-off head clarifier;
The outlet of said secondary stage purified device is through linking to each other with said main heat exchanger, and said main heat exchanger links to each other with the said cold heat exchanger of crossing through the 4th internal pipeline, and the said cold heat exchanger of crossing links to each other with the expanding end import of said cold junction booster expansion turbine;
The expanding end outlet of said cold junction booster expansion turbine links to each other with the said cold heat exchanger of crossing through the 5th internal pipeline, and the said cold heat exchanger of crossing links to each other with said main heat exchanger through pipeline;
Said main heat exchanger links to each other with the pressurized end import of said cold junction booster expansion turbine through pipeline;
The pressurized end outlet of said cold junction booster expansion turbine links to each other with said compressor through pipeline, and said compressor is connected with said low pressure pipeline.
Preferably, in the two differential energy-conservation liquefying plants of decompressor in above-mentioned natural gas transmission main line double loop, said liquified natural gas stocking system comprises gas-liquid separator and LNG tank;
Said main heat exchanger links to each other with the said cold heat exchanger of crossing through pipeline, and the said cold heat exchanger of crossing is connected with said gas-liquid separator through pipeline;
The gas outlet end of said gas-liquid separator links to each other with the expanding end outlet of said cold junction booster expansion turbine through internal pipeline, and the liquid outlet end of said gas-liquid separator is connected with said LNG tank.
Preferably, in the two differential energy-conservation liquefying plants of decompressor in above-mentioned natural gas transmission main line double loop, the pressurized end outlet of said hot junction booster expansion turbine and the pressurized end exit of said cold junction booster expansion turbine are equipped with the supercharger aftercooler.
Based on above-mentioned setting, the two differential energy-conservation liquefying plants of decompressor in the natural gas transmission main line double loop that the utility model provides through adopting the constant entropy Refrigeration Technique of the two decompressors of parallel connection, can be converted into cold energy to the pressure of natural gas.Realize transforming the liquefaction of part natural gas in the pipeline out liquefied natural gas product (accounting for more than 10% of pipe natural gas conveying capacity) and to store through the liquified natural gas stocking system, this technology for recovery pressure can, turn waste into wealth.The liquefied natural gas that stores can be used as commodity, also can store to be used for natural gas trunk line and pipeline network of fuel gas in city peak regulation.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
The system diagram of the two differential energy-conservation liquefying plants of decompressor in the natural gas transmission main line double loop that Fig. 1 provides for the utility model embodiment;
The system diagram of the natural gas transmission main line that Fig. 2 provides for the utility model embodiment.
The specific embodiment
The utility model discloses the two differential energy-conservation liquefying plants of decompressor in a kind of natural gas transmission main line double loop,, improve liquefied fraction importing and exporting under the low situation of pressure ratio.
To combine the accompanying drawing among the utility model embodiment below, the technical scheme among the utility model embodiment is carried out clear, intactly description, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.
See also Fig. 1 and Fig. 2, the system diagram of the two differential energy-conservation liquefying plants of decompressor in the natural gas transmission main line double loop that Fig. 1 provides for the utility model embodiment; The system diagram of the natural gas transmission main line that Fig. 2 provides for the utility model embodiment.
The two differential energy-conservation liquefying plants of decompressor in the natural gas transmission main line double loop that the utility model embodiment provides; Be used for the natural gas transmission main line; Comprise and be used for the pressure piping 10 that is communicated with main pressure piping 12; And being used for the low pressure pipeline 11 that is communicated with the natural valve of user station 14, focusing on of the utility model also comprises first order expander system, second level expander system and liquified natural gas stocking system.Main pressure piping 12 is natural gas transmission trunk lines, and pressure is 8.0-10.0Mpa, and low pressure pipeline 11 is connecting the natural valve of user station 14, and pressure is 4.0Mpa.
Wherein, first order expander system and second level expander system are in parallel, and are communicated with pressure piping 10 and low pressure pipeline 11 respectively, and the liquified natural gas stocking system is parallelly connected with second level expander system.
The two differential energy-conservation liquefying plants of decompressor in the natural gas transmission main line double loop that the utility model provides through adopting the constant entropy Refrigeration Technique of the two decompressors of parallel connection, can be converted into cold energy to the pressure of natural gas.Realize transforming the liquefaction of part natural gas in the pipeline out liquefied natural gas product (accounting for more than 10% of pipe natural gas conveying capacity) and to store through the liquified natural gas stocking system, this technology for recovery pressure can, turn waste into wealth.The liquefied natural gas that stores can be used as commodity, also can store to be used for natural gas trunk line and pipeline network of fuel gas in city peak regulation.
In order further to optimize technique scheme; The utility model embodiment also can comprise the chopped-off head clarifier 8 that is arranged between first order expander system and second level expander system and the pressure piping 10, and chopped-off head clarifier 8 is used for removing the moisture and the benzene of natural gas.
In the present embodiment, first order expander system comprises hot junction booster expansion turbine 6, main heat exchanger 2 and crosses cold heat exchanger 3.Wherein, the expanding end import of hot junction booster expansion turbine 6 is connected with the outlet of chopped-off head clarifier 8 through first internal pipeline 91.The expanding end outlet of hot junction booster expansion turbine 6 links to each other with main heat exchanger 2 through second internal pipeline 92, and main heat exchanger 2 links to each other with the pressurized end import of hot junction booster expansion turbine 6 through the 3rd internal pipeline 93.The pressurized end outlet of hot junction booster expansion turbine 6 links to each other with low pressure pipeline 11 through pipeline.
In the present embodiment, second level expander system comprises cold junction booster expansion turbine 15, compressor 1 and secondary stage purified device 7, and secondary stage purified device 7 is connected with chopped-off head clarifier 8.The outlet of secondary stage purified device 7 is through linking to each other with main heat exchanger 2, and main heat exchanger 2 links to each other with mistake cold heat exchanger 3 through the 4th internal pipeline 94, crosses cold heat exchanger 3 and links to each other with the expanding end import of cold junction booster expansion turbine 15.The outlet of the expanding end of cold junction booster expansion turbine 15 through the 5th internal pipeline 95 with cross cold heat exchanger 3 and link to each other, cross cold heat exchanger 3 and pass through pipeline and link to each other with main heat exchanger 2.Main heat exchanger 2 links to each other with the pressurized end import of cold junction booster expansion turbine 15 through pipeline, and the pressurized end outlet of cold junction booster expansion turbine 15 links to each other with compressor 1 through pipeline, and compressor is connected with low pressure pipeline 11.
In the present embodiment, the liquified natural gas stocking system comprises gas-liquid separator 4 and LNG tank 5.Main heat exchanger 2 links to each other with mistake cold heat exchanger 3 through pipeline, crosses cold heat exchanger 3 and is connected with gas-liquid separator 4 through pipeline.The gas outlet end of gas-liquid separator 4 links to each other with the expanding end outlet of cold junction booster expansion turbine 15 through internal pipeline, and the liquid outlet end of gas-liquid separator 4 is connected with LNG tank 5.
In the utility model one preferred embodiment, the pressurized end exit of outlet of the pressurized end of hot junction booster expansion turbine 6 and cold junction booster expansion turbine 15 is equipped with the supercharger aftercooler.
At first pass through chopped-off head clarifier 8 from the high-pressure natural gas of main pressure piping 12, divide two-way after removing moisture and benzene.
One tunnel air-flow that is used for expanding is cooled to-30 ℃ approximately through secondary stage purified device 7 at main heat exchanger 2, behind hot junction booster expansion turbine 6, is expanded to about 2.5Mpa pressure;-90 ℃, return main heat exchanger 2 re-heats then to normal temperature, get into the pressurized end of hot junction booster expansion turbine 6 then; Be pressurized to about 4.0Mpa; And then be cooled to normal temperature through the supercharger aftercooler, and get into the low pressure pipeline 11 of downstream 4.0Mpa, give the natural valve of user station 14.
Another road is used to liquefy and the air-flow of cold junction booster expansion turbine 15 is removed CO through secondary stage purified device 7
2, cooling in main heat exchanger 2 then, a part was passed through cold heat exchanger 3 cooling backs and was got into cold junction booster expansion turbine 15, was expanded to about 0.4Mpa pressure ,-134 ℃.Another part is crossed cold deutomerite through cold heat exchanger 3 and is flow to 0.4Mpa; Separate through gas-liquid separator 4; Liquefied natural gas gets into LNG tank 5, gas with passed through cold heat exchanger 3 and main heat exchanger 2 re-heats after the gas of cold junction booster expansion turbine 15 expanding ends outlet mixes successively to normal temperature, then after compressor 1 compresses; Return the low pressure pipeline 11 of 4.0Mpa through internal pipeline 9, and then get into the natural valve of user station 14.
In sum, the utlity model has following beneficial effect:
1) the utility model has reclaimed the pressure ability, turns waste into wealth;
2) liquefied natural gas in the LNG tank that transforms out of the utility model can be used as commodity, also can store to be used for natural gas trunk line and city domestic gas pipe network peak regulation;
3) the utility model switch is not at any time lost time, and does not have condition restriction;
4) the utility model does not produce any side effect, and is practical, energy-conserving and environment-protective;
5) the utility model has only 1.5-3.0Mpa with pressure reduction, imports and exports pressure ratio and is increased to more than 10% less than the liquefied rate of 2.5 the differential liquefying plant of natural gas line, has improved the yield of liquefied natural gas.
The natural gas transmission main line that the utility model embodiment provides; The branch defeated station regulator 13 that comprises main pressure piping 12, links to each other with main pressure piping 12 through pipeline and with the natural valve of the user station 14 of dividing the defeated regulator 13 of standing to connect; Focusing on of the utility model; Also comprise and divide defeated station regulator 13 parallelly connected, and the disclosed natural gas transmission main line of the as above embodiment double loop of connect with the natural valve of the user station 14 pair differential energy-conservation liquefying plants of decompressor.
The gas time period at the peak of gas transmission, the pipe natural gas of natural gas transmission main line liquefiable more than 10% that the utility model provides, the post-decompression natural gas of liquefaction does not remove user's natural gas line network, divides defeated station regulator 13 to stop using; In the deficency time period, the utility model reduces the liquefaction amount even stops using, and opens and divides defeated station regulator 13.
Each embodiment adopts the mode of going forward one by one to describe in this specification, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.
To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the utility model.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined General Principle can realize under the situation of spirit that does not break away from the utility model or scope in other embodiments among this paper.Therefore, the utility model will can not be restricted to these embodiment shown in this paper, but will meet and principle disclosed herein and features of novelty the wideest corresponding to scope.