A kind of rectification type self-stacking gas liquefaction system
Technical field
The present invention relates to a kind of gas liquefaction system, relate in particular to a kind of rectification type self-stacking gas liquefaction system.
Background technology
In extensive natural gas liquefaction engineering, the mix refrigerant self-stacking gas liquefaction system has substituted classical superposition type gas liquefaction system, is widely used.But; Because these traditional mixing refrigerant gas liquefaction systems have adopted 2~5 grades equilibrium separation fractional condensation process, the treatment situation of lubricating oil has obtained very big improvement, becomes complicated but the structure of circulation is corresponding; Running is to the adaptability variation of source of the gas and environment temperature, and is restive.Particularly concerning small-sized and minitype gas liquefying plant, equipment simply is very important decisive factor, and above-mentioned traditional liquefaction system can not adapt to the miniaturization and the microminiaturization of gas liquefaction system.
Application number is the rectification type mix refrigerant deep refrigerating device that the patent documentation of CN02110664.9 proposes; The a plurality of gas-liquid separators that rectifier unit replaces repeatedly fractional condensation to circulate have been adopted; The oil that can realize repeatedly fractional condensation circulation separates effect, and has higher cycle efficieny.But said system is only applicable to the occasion of general refrigeration to be used, and complicated integral structure, and in addition, above-mentioned refrigeration system is not considered the water equivalent ratio between cold-producing medium and the liquefied gas, and heat transfer temperature difference is big in the running, and thermal losses is big.
Summary of the invention
The invention provides a kind of rectification type self-stacking gas liquefaction system, this liquefaction system is simple in structure, reliable and system's liquefaction efficiency is high, and thermal losses is little, and use cost is low.
A kind of rectification type self-stacking gas liquefaction system comprises compressor, condenser, rectifier unit and unstripped gas liquefaction loop; Described compressor discharging opening links to each other with the condenser charging aperture; Charging aperture links to each other in the discharging opening of described condenser and the rectifier unit still; Described rectifier unit comprises rectifying column and the cat head heat exchanger that is communicated with rectifying column rectifying section top; The discharging opening at cat head heat exchanger top links to each other with unstripped gas liquefaction loop; Unstripped gas passes described unstripped gas liquefaction loop and obtains final liquiefied product, second heat exchanger package that described unstripped gas liquefaction loop comprises first heat exchanger package be made up of first heat exchanger, second heat exchanger, be made up of the 3rd heat exchanger and be located at first heat exchanger package and second heat exchanger package between the first throttle valve;
Be equipped with a refrigerant tubing and unstripped gas liquefaction pipeline in described first heat exchanger and second heat exchanger, be equipped with some chargings that are communicated with inner chamber or discharging port on the outer wall; Be provided with a unstripped gas liquefaction pipeline in described the 3rd heat exchanger, outer wall is provided with some chargings that are communicated with inner chamber or discharging port; Be provided with cooling pipe in the described cat head heat exchanger;
The discharging opening at described cat head heat exchanger top links to each other with the entrance point of the refrigerant tubing of first heat exchanger; The port of export of the refrigerant tubing of described first heat exchanger links to each other with the refrigerant tubing entrance point of second heat exchanger; The charging aperture of described first throttle element links to each other with the refrigerant tubing port of export of second heat exchanger, and discharging opening is communicated with the charging port at the 3rd heat exchanger top; The discharging port of described the 3rd heat exchanger bottom is communicated with the charging port of second heat exchanger bottom, with realization pre-cooled to refrigerant tubing inner refrigerant and unstripped gas; The discharging port at the described second heat exchanger top is communicated with the interior cooling pipe entrance point of cat head heat exchanger; The cooling pipe port of export of described cat head heat exchanger is communicated with the compressor air suction mouth, realizes the circularly cooling of cold-producing medium;
Second discharging opening of described cat head heat exchanger bottom is communicated with the charging port of the outer wall of first heat exchanger, second heat exchanger and the 3rd heat exchanger respectively through three bypass line, is respectively equipped with a restricting element on the described branch road;
Liquid outlet is communicated with the charging port of first heat exchanger, second heat exchanger and the 3rd heat exchanger outer wall respectively through three bypass line at the bottom of the described rectifying Tata, is respectively equipped with a restricting element on the described branch road;
The discharging port at the described first heat exchanger top is communicated with the compressor air suction mouth, realizes the cold-producing medium circularly cooling in first heat exchanger cavity.
The present invention adopts the unstrpped gas that will liquefy to get into successively in three heat exchangers in unstripped gas liquefaction loop; The highly pressurised liquid of the heterogeneity that utilization is drawn from rectifier unit bottom and top; According to the feed gas composition characteristics; Feed after the throttling respectively in three heat exchangers in unstripped gas liquefaction loop, change, come to cool off piecemeal unstripped gas with the water equivalent in the optimization of matching unstripped gas cooling liquefaction process; Reduce the heat transfer temperature difference between the interior mix refrigerant of three different temperatures section heat exchangers and mix refrigerant and the liquefied gas, thereby reduce the unit liquefaction merit of gas liquefaction system.
Described first heat exchanger package or second heat exchanger package can increase or reduce the wherein quantity of heat exchanger according to actual needs.
For further strengthening the thorough cooling of unstripped gas; In the optimized technical scheme; The port of export of unstripped gas liquefaction pipeline is positioned at the top of the 3rd heat exchanger in described the 3rd heat exchanger; Entrance point is positioned at the bottom of the 3rd heat exchanger, this moment the 3rd heat exchanger in unstripped gas with through the reverse contact heat-exchanging of the cooled cold-producing medium of first throttle element throttling, improved heat exchanger effectiveness.
For guaranteeing the stability of whole liquefaction system, realize the comprehensive utilization of the energy simultaneously, in the optimized technical scheme, can on the fluid pipeline at the bottom of the described rectifying Tata, one or more devices for drying and filtering be set, to realize the dry of kettle base solution and to filter; Heat exchanger at the bottom of one or more stills also can be set simultaneously, be convenient to precooling treatment kettle base solution; When the number of device for drying and filtering of selecting and heat exchanger was one, liquid outlet linked to each other with heat exchanger at the bottom of device for drying and filtering and the still at first successively at the bottom of the described rectifying Tata, and then links to each other with described three bypass line; Described device for drying and filtering charging aperture is communicated with liquid outlet at the bottom of the rectifying Tata, and discharging opening links to each other with the entrance point of one of them pipeline in the heat exchanger at the bottom of the still, and the port of export of this pipeline links to each other with described three bypass line; The entrance point of another pipeline is communicated with in the described cat head heat exchanger cooling pipe port of export and the heat exchanger at the bottom of the still, and the port of export of this pipeline is communicated with the compressor air suction mouth, be used for the higher boiling cold-producing medium at the bottom of the tower is carried out pre-cooled, with the comprehensive utilization of realization energy; The entrance point of two pipelines at the bottom of the described still in the heat exchanger is located at the both sides of heat exchanger at the bottom of the still respectively, is convenient to realize countercurrent flow; The setting of heat exchanger at the bottom of the still can utilize the cooling agent of discharging in the cat head heat exchanger cooling pipe that kettle base solution is carried out precooling.
Heat exchanger, first heat exchanger, second heat exchanger or the 3rd heat exchanger can be selected conventional immersion, fountain, shell and tube, bushing type or plate type heat exchanger for use at the bottom of described condenser, the still.The pipeline that connects according to actual needs, selection is fit to the heat exchanger of model and structure.
Cold-producing medium in the described liquefaction system can be selected binary or the above mixed non-azeotropic refrigerant of binary for use.The common component of forming mixed non-azeotropic refrigerant mainly contains: the halide of nitrogen, inert gas, carbon hydro carbons, hydrocarbon, carbon dioxide etc.Described restricting element can be selected manual throttle valve common on the market, automatic throttle or capillary for use; Restricting element.Described rectifying column can be selected conventional packed tower or plate column for use.
The present invention compared with prior art can realize following beneficial effect:
(1) structure of liquefaction system is greatly simplified, and is reliable good.Utilize rectifier unit to replace 2~5 grades of separation processes of conventional hybrid refrigerant gas liquefaction system; Make the structure of liquefaction system greatly simplify; Can the lubricating oil of the cold-producing medium that enters into low-pressure section be removed effectively simultaneously, guarantee the reliability service of liquefaction system.
(2) can improve the thermodynamic efficiency of liquefaction system.Different according to water equivalent characteristic distributions in the variety classes unstripped gas liquefaction process and flow; The flow of highly pressurised liquid mix refrigerant that can be through regulating two bursts of heterogeneities of drawing from rectifier unit bottom and top; And they are at the hybrid position of three heat exchangers of gas liquefaction system; Optimize the water equivalent proportioning between the interior mix refrigerant of heat exchanger and mix refrigerant and the liquefied gas; Can reduce the heat transfer temperature difference of three different temperatures section heat exchangers, thereby reduce the unit liquefaction merit of gas liquefaction system.
Description of drawings
Fig. 1 is the structural representation of first kind of embodiment of rectification type self-stacking gas liquefaction system of the present invention;
Fig. 2 is the structural representation of second kind of embodiment of rectification type self-stacking gas liquefaction system of the present invention.
The specific embodiment
Embodiment 1
Shown in accompanying drawing 1; A kind of rectification type self-stacking gas liquefaction system comprises compressor 1, condenser 2, rectifier unit 3, first heat exchanger 6, second heat exchanger 7, the 3rd heat exchanger 8, first throttle element 9, second restricting element 10, the 3rd restricting element 11, the 4th restricting element 12, the 5th restricting element 13, the 6th restricting element 14, the 7th restricting element 15.Rectifier unit 3 comprises rectifying column and the cat head heat exchanger that is communicated with rectifying column rectifying section top.Be equipped with a refrigerant tubing and unstripped gas liquefaction pipeline in first heat exchanger 6 and second heat exchanger 7, be equipped with some chargings that are communicated with inner chamber or discharging port on the outer wall.Be provided with a unstripped gas liquefaction pipeline in the 3rd heat exchanger 8, outer wall is provided with some charging ports that are communicated with inner chamber or discharging port; Be provided with cooling pipe in the cat head heat exchanger.
The discharging opening 1b of compressor 1 links to each other with the charging aperture 2a of condenser 2; Charging aperture 3a links to each other in the discharging opening 2b of condenser 2 and the tower of the rectifying column of rectifier unit 3, and liquid outlet 3b links to each other with the charging aperture 13a of the 5th restricting element 13, the charging aperture 14a of the 6th restricting element 14, the charging aperture 15a of the 7th restricting element 15 respectively at the bottom of the rectifying Tata of rectifier unit 3.
The discharging opening 3e at the cat head heat exchanger top of rectifier unit 3 links to each other with the entrance point 6a of the refrigerant tubing of first heat exchanger 6; The second discharging opening 3f of the cat head heat exchanger bottom of rectifier unit 3 links to each other with the charging aperture 10a of second restricting element 10, the charging aperture 11a of the 3rd restricting element 11 and the charging aperture 12a of the 4th restricting element 12 respectively.
The port of export 6b of the refrigerant tubing of first heat exchanger 6 links to each other with the entrance point 7a of the refrigerant tubing of second heat exchanger 7; The unstripped gas liquefaction pipe head 6c of first heat exchanger 6 is the inlet of raw materials treated gas, and the unstripped gas liquefaction pipe outlet 6d of first heat exchanger 6 links to each other with the unstripped gas liquefaction pipe head 7e of second heat exchanger 7; The bottom of first heat exchanger 6 is provided with two charging port 6f and 6g, and one of them charging port 6f links to each other with the discharging opening 10b of second restricting element 10, and another charging port 6g of first heat exchanger, 6 bottoms links to each other with the discharging opening 13b of the 5th restricting element 13; First heat exchanger, 6 tops are provided with a discharging port 6e, and discharging port 6e links to each other with the air entry 1a of compressor 1; Port of export 6b, the 6d of refrigerant tubing in first heat exchanger 6 and unstripped gas liquefaction pipeline all is positioned at a side of first heat exchanger 6, and entrance point 6a, 6c are positioned at the opposite side of first heat exchanger 6.
The port of export 7b of the refrigerant tubing of second heat exchanger 7 links to each other with the charging aperture 9a of first throttle element 9, and the discharging opening 9b of first throttle element 9 links to each other with the charging port 8c on the 3rd heat exchanger 8 tops; The port of export 7f of the unstripped gas liquefaction pipeline of second heat exchanger 7 links to each other with the entrance point 8a of the unstripped gas pipeline of the 3rd heat exchanger 8; Second heat exchanger, 7 one sides are provided with four port 7d, 7g, 7h and 7c; Wherein, discharging port 7d links to each other with the entrance point 3c of cooling pipe in the cat head heat exchanger, and the port of export 3d of cooling pipe links to each other with the air entry 1a of compressor 1 in the cat head heat exchanger; Charging port 7g links to each other with the discharging opening 14b of the 6th restricting element 14; Charging port 7h links to each other with the discharging opening 11b of the 3rd restricting element 11; Charging port 7c links to each other with the discharging port 8d of the 3rd heat exchanger 8 bottoms.The port of export 7b of refrigerant tubing in second heat exchanger 7 and unstripped gas liquefaction pipeline, the bottom that 7f all is positioned at second heat exchanger 7, entrance point 7a, 7e are positioned at the top of second heat exchanger 7.
The unstripped gas liquefied gas pipeline entrance point 8a of the 3rd heat exchanger 8 is positioned at the bottom of the 3rd heat exchanger 8, so that the inner reverse heat transfer of heat exchanger; The 3rd heat exchanger 8 one sides are provided with two charging port 8e and 8f, and wherein charging port 8e links to each other with the discharging opening of the 4th restricting element 12, and charging port 8f links to each other with the discharging opening of the 7th restricting element 15.The entrance point 8a of the unstripped gas pipeline of the 3rd heat exchanger 8 is positioned at the bottom of heat exchanger, and the port of export of unstripped gas pipeline is positioned at the top of heat exchanger, as the outlet of last liquiefied product.
Condenser 2 in the above-mentioned embodiment, cat head heat exchanger, first heat exchanger 6, second heat exchanger 7, the 3rd heat exchanger 8 can be selected common immersion heat exchanger, spray-type heat exchanger, tubular heat exchanger, double pipe heat exchanger or plate type heat exchanger for use.
First throttle element 9 in the above-mentioned embodiment, second restricting element 10, the 3rd restricting element 11, the 4th restricting element 12, the 5th restricting element 13, the 6th restricting element 14 or the 7th restricting element 15 can be selected conventional manual throttle valve, automatic throttle or capillary for use, to play the effect of throttling cooling.
Rectifier unit in the above-mentioned embodiment in rectifier unit and the common refrigerating plant is similar, and its rectifying column can be selected conventional plate distillation column or material filling type rectifying column for use.
Connection between above-mentioned said each parts adopts refrigerant line to connect cryogenic pipe outerwrap thermal-insulating waterproof material.
The used cold-producing medium of liquefaction system is binary or the above mixed non-azeotropic refrigerant of binary.The common component of forming mixed non-azeotropic refrigerant mainly contains: the halide of nitrogen, inert gas, carbon hydro carbons, hydrocarbon, carbon dioxide etc.
For ease of understanding, we can be divided into refrigerant loop and liquefied gas loop with above-mentioned rectification type self-stacking gas liquefaction system, below are detailed workflows:
In the refrigerant loop, mix refrigerant is cooled to the high-pressure fluid of gas-liquid two-phase through condenser 2 after compressor 1 pressurization, then flow in the still of rectifier unit 3.Wherein, the gaseous state mix refrigerant through the rectifying section of rectifier unit 3, carries out heat, matter exchange with the defluent phegma in rectifier unit 3 tops from bottom to top; High boiling component and lubricating oil and a small amount of low boiling component are condensed a part that becomes phegma; Most of low boiling component be main gaseous state mix refrigerant through rectifier unit 3 heat exchange of top part devices, flow out from the discharging opening 3e at the top of heat exchange of top part device.Successively through first heat exchanger 6 and second heat exchanger 7; Then get into first throttle element 9 throttlings cooling; Get into the 3rd heat exchanger 8 cooling fluid gasifications subsequently, backflow successively then, return the air entry of compressor 1 through second heat exchanger 7 and rectifier unit 3 heat exchange of top part device re-heats.
With middle boiling point component is second discharging opening 3f direct entering second restricting element 10 or three restricting element 11 or four restricting element 12 of master's liquid mix refrigerant from cat head heat exchanger bottom.Through regulating the aperture of second restricting element 10, the 3rd restricting element 11 and the 4th restricting element 12; Can to realize middle boiling point component be main mix refrigerant gets into first heat exchanger 6, second heat exchanger 7 and the 3rd heat exchanger 8 with any suitable ratio, to satisfy the water equivalent coupling requirement of these three heat exchangers.
Being main liquid mix refrigerant with the high boiling component at the bottom of the rectifying Tata, liquid outlet 3b flows into the 5th restricting element 13 or the 6th restricting element 14 or the 7th restricting element 15 respectively.Through regulating the aperture of the 5th restricting element 13 or the 6th restricting element 14 or the 7th restricting element 15; Can to realize high boiling component be main mix refrigerant gets into first heat exchanger 6, second heat exchanger 7 and the 3rd heat exchanger 8 with any suitable ratio, to satisfy the water equivalent coupling requirement of these three heat exchangers.
In the liquefied gas loop; Unstripped gas after purified treatment gets into liquefaction system from the unstripped gas liquefaction pipe head 6c of first heat exchanger 6; Successively through the liquefaction that is cooled of first heat exchanger 6, second heat exchanger 7 and the 3rd heat exchanger 8, liquiefied product is sent to the liquid gas stocking system from the unstripped gas liquefaction pipe outlet 8b of the 3rd heat exchanger 8 at last and preserves.
Embodiment 2
And embodiment 1 difference only is heat exchanger 5 at the bottom of being provided with device for drying and filtering 4 and still between rectifier bottoms and the 5th restricting element 13 or the 6th restricting element 14 or the 7th restricting element 15.Wherein, Liquid outlet 3b links to each other with the charging aperture 4a of device for drying and filtering 4 earlier at the bottom of the rectifying Tata of rectifier unit 3; The discharging opening 4b of device for drying and filtering 4 links to each other with the entrance point 5a of one of them pipeline in the heat exchanger at the bottom of the still 5, and the port of export 5b of this pipeline links to each other with the charging aperture of described the 5th restricting element 13 or the 6th restricting element 14 or the 7th restricting element 15 respectively; The entrance point 5c of heat exchanger 5 interior another pipelines links to each other at the bottom of the still, and the port of export 5d of this pipeline is communicated with compressor 1 air entry 1a; Entrance point 5a, the 5c of two pipelines at the bottom of the still in the heat exchanger 5 is located at the both sides of heat exchanger 5 at the bottom of the still respectively, guarantees material reverse flow in two pipelines, the raising cooling effectiveness.
According to the needs of different occasions, the number of heat exchanger can be adjusted in first heat exchanger package or second heat exchanger package, to satisfy the needs of actual cooling condition.