DE2055229A1 - Natural gas fractionation - into low and high nitrogen fractions - Google Patents

Natural gas fractionation - into low and high nitrogen fractions

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Publication number
DE2055229A1
DE2055229A1 DE19702055229 DE2055229A DE2055229A1 DE 2055229 A1 DE2055229 A1 DE 2055229A1 DE 19702055229 DE19702055229 DE 19702055229 DE 2055229 A DE2055229 A DE 2055229A DE 2055229 A1 DE2055229 A1 DE 2055229A1
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Germany
Prior art keywords
column
nitrogen
natural gas
pressure
rich
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Pending
Application number
DE19702055229
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German (de)
Inventor
Friedrich DipL-Ing. 6000 Bergen-Enkheim; Tanz Heiner Dipl.-Ing. 6451 Dörnigheim Juncker
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Messer Griesheim GmbH
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Messer Griesheim GmbH
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Priority claimed from DE2022954A external-priority patent/DE2022954C3/en
Application filed by Messer Griesheim GmbH filed Critical Messer Griesheim GmbH
Priority to DE19702055229 priority Critical patent/DE2055229A1/en
Publication of DE2055229A1 publication Critical patent/DE2055229A1/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0257—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of nitrogen
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/40—Features relating to the provision of boil-up in the bottom of a column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
    • F25J2205/04—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum in the feed line, i.e. upstream of the fractionation step
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/60—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being hydrocarbons or a mixture of hydrocarbons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/60—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being (a mixture of) hydrocarbons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
    • F25J2240/12—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream the fluid being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/02—Recycle of a stream in general, e.g. a by-pass stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/02—Internal refrigeration with liquid vaporising loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/04—Internal refrigeration with work-producing gas expansion loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/88—Quasi-closed internal refrigeration or heat pump cycle, if not otherwise provided

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Analytical Chemistry (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

Low and high nitrogen fractions are produced in single-stage column distillation, the reflux required being produced by free expansion of the major part of the high-nitrogen fraction and evaporation of a circulating medium, as in the parent patent. The cooling effect produced by evaporating the circulating medium is applied to the column head, while that produced by expanding the high-nitrogen fraction is applied below the column head at a higher temp.

Description

Verfahren zur Zerlegung von stickstoffhaltigem Erdgas Die Erfindung betrifft ein Verfahren zur Zerlegung von stickstoffhaltigem Erdgas in eine stickstoffarme und in eine stickstoffreiche Fraktion durch einstufige Destillation in einer Kolonne nach Prtentanmeldung P 20 22 954.3.Method for the decomposition of nitrogenous natural gas The invention relates to a method for breaking down nitrogen-containing natural gas into a nitrogen-poor one and into a nitrogen-rich fraction by single-stage distillation in a column after registration P 20 22 954.3.

Nach dem Verfahren der Hauptanmeldung wird der für die Destillation erforderliche Rücklauf durch arbeitsleistende Entspannung zumindest des größten Teils der stickstoffreichen Fraktion und durch Verdampfen eines Kreislaufmediums erzeugt.The procedure of the main application is used for distillation required return through work-performing relaxation at least the greatest Part of the nitrogen-rich fraction and by evaporation of a circulating medium generated.

Es muß dabei entweder die bei der Entspannung der stickstoffreichen Franktion encstehende Kälte oder die Kreislaufkälte am Kolonnenkopf, also am Kältesten Teile der Kolonne angeboten werden. Die restliche Kälte kann auf einem höheren Temperaturniveau an andererstolle der Kolonne angeboten erden. Im Hauptpatent sind zwei Ausführungsbeispiele beschrieben, bei dem die Kreislauflçtlte auf höheren Temperaturniveau im mittleren Teil der Kolonne angeboten wird.It must either be used in the relaxation of the nitrogen-rich Fraction of the cold or the circulatory cold at the top of the column, i.e. the coldest Parts of the column are offered. The remaining cold can be at a higher temperature level offered at other stalls of the column. There are two exemplary embodiments in the main patent described in which the circulating oil at a higher temperature level in the middle Part of the column is offered.

Es wurde nun gefunden, daß man das Verfahren nach der Patentanmeldung P 20 22 954.) weiter verbessern kann, wenn gemäß der Erfindung die durch Verdampfen des Kreislaufmediums entstehende Kilte am Kolonnenkopf und die durch Entspannen der stickstoffreichen Fraktion entEtehende Kälte unterhalb des Kolonnenkopfes auf einem höheren Temperaturniveau zur Erzeugung von Rücklauf dient.It has now been found that one can use the method according to the patent application P 20 22 954.) can improve further if according to the invention by evaporation of the circulating medium at the top of the column and the pressure caused by expansion the nitrogen-rich fraction is exposed to the cold below the top of the column a higher temperature level is used to generate return.

Die Verbesserung besteht vor allem darin, daß die Rektifikation mit einem geringeren Energiebedarf durchgeführt werden kann.The improvement consists mainly in the fact that the rectification with can be carried out with a lower energy requirement.

Infolgedessen l:ßt sich der Kreislaufdruck wesentlich senken.As a result, the circuit pressure can be reduced significantly.

Es ist möglich, den Kreislaufdruck gleich dem Kolonnendruck zu machen. Wenri man einen offenen Kreislauf verwendet, kann als Kreislaufmedium ohne weitere Druckerhöhung direkt ein Teil der äbgezogeneri Sumpfflüssigkeit dienen. Wenn der Stickstoffgehalt im Erdgas genügend hoch ist, reicht die bei der Entspannung der stickstoffreichen Fraktion freiwerdende Energie aus, den Kreisaufverdichter ohne Zusatz von Fremdenergie anzutreiben. Durch die bei der arbeitsleiEtenden Entspannung der stickstoffreiclien Fraktion freiwerdende Kälte kann der Rücklauf auch auf die Art erzeugt werden, daß mit ihr ein Teil strom des Rohgases verflüssigt wird und oberhalb der Aufgabestelle des anderen Teilstromes in die Kolonne geleitet wird.It is possible to make the circuit pressure equal to the column pressure. If an open circuit is used, it can be used as a circulating medium without any further Part of the withdrawn sump liquid is used to directly increase the pressure. If the The nitrogen content in the natural gas is high enough, which is sufficient for the relaxation of the nitrogen-rich fraction from the energy released, the circular compressor without To drive the addition of external energy. Through the relaxation during work The cold released from the nitrogen-rich fraction can also be fed back to the Kind be generated that with her part of the stream of the raw gas is liquefied and is passed into the column above the point of application of the other substream.

Man kann das Rohgas auch durch Entspannen teilweise verflüssigert und den verflüssigten Anteil an tiefer Stelle in die Kolonne leiten, während der gasförmig gebliebene Anteil durch die bei der arbeitsleistenden Entspannung der stickstoffreichen Fraktion freiwerdende Kälte verflüssigt wird und an höherer Stelle in die Kolonne geleitet wird.The raw gas can also be partially liquefied by letting down the pressure and direct the liquefied fraction deeper into the column, during the Part remaining gaseous due to the relaxation of the work-performing nitrogen-rich fraction released cold is liquefied and at a higher point is passed into the column.

Zwei Ausführungsbeispiele der Erfindung sollen anhand der beigefügten Zeichnungen erläutert werden.Two embodiments of the invention should be based on the attached Drawings are explained.

Es zeigen: Fig. 1 eine Ausführung des erfindungsgemäßen Verfahrens, bei der die durch die arbeitsleistende Entspannung der stickstoffreichen Fraktion freiwerdende Kälte direkt in der Kolonne angeboten wird, Fig. 2 eine Ausführung, bei der die durch die arbeitsleistende Entspannung der stickstoffreichen Fraktion freiwerdende Kälte dazu dient, einen Teil des Rohgases zu verflüssigen.1 shows an embodiment of the method according to the invention, in which the work-performing relaxation of the nitrogen-rich fraction released cold is offered directly in the column, Fig. 2 shows an embodiment, in which the work-performing relaxation of the nitrogen-rich fraction The cold released serves to liquefy part of the raw gas.

Als Bezugsziffern wurden die Bezugsziffern der Hauptanmeldung verwendet, soweit es sich um identische Teile handelt.The reference numbers of the main application were used as reference numbers, as far as the parts are identical.

Bei dem Ausführungsbeispiele nach Fig. 1 tritt das zu behandelnde Erdgas über Leitung 1 in die Anlage i. Im Wärmeaustauscher 2 wird es gegen zurückströmende Stoffströme abgekühlt und beheizt dann im Verdampfer 3 den Sumpf der Kolonne 4. Danach wird es im Drosselventile 7 auf den Kolonnendruck entspannt unc in die Kolonne 4 geleitet. Durch Leitung 8 Wird vom Kolonnenkopf eine stikstoffreiche Fraktion abgezogen, die Je nachdem, wie weit man die Rektifikation treibt, auch reiner Stickstoff sein kann. Die e stickstoffreiche Fraktion durchläuft den Wä.rmeaustauscher 9 und wird in der Turbine 10 einstufig entspannt, wobei sie sich abkühlt. Die entstandene Kälte dient im Wärmeaustauscher 11, deX etwa in der Mitte der Kolonne 4 angeordnet ist, dazu, einen Teil des für die Destillation erforderlichen Rücklauf zu erzeugen. Ihre restliche Kälte gibt die stickstoffreiche Fraktion und in den Wärmeaustauschern 5 und 2 ab, wonach sie über die Leitung 32 die Anlage verläßt. Die stickstoffarme Fraktion, die Je nachdem, wie weit man die Rektifikation treibt, auch nahezu reines Methan sein kann, wird über Leitung 20 flüssig vom Fuß der Kolonne 4 abgezogen. D&r größte Teil des Sumpfproduktes gelangt dann durch Leitung; 33 zur Pumpe 21, in der es auf höheren Druck verdichtet wird, z.B. auf den Druck des eintretenden Erdgases von über 35 atü. Nach Kälteabgabe im Wärmeaustauscher 2 verläßt es die Anlage über Leitung )4.In the exemplary embodiment according to FIG. 1, that to be treated occurs Natural gas via line 1 into the plant i. In the heat exchanger 2 it is against backflow Material flows are cooled and then heated in the evaporator 3, the bottom of the column 4. It is then released in the throttle valve 7 to the column pressure and into the column 4 headed. A fraction rich in nitrogen is obtained from the top of the column through line 8 deducted, depending on how far you go the rectification, also pure nitrogen can be. The nitrogen-rich fraction passes through the heat exchanger 9 and is expanded in one stage in the turbine 10, where it cools down. The resulting Cold is used in the heat exchanger 11, deX arranged approximately in the middle of the column 4 is to generate part of the reflux required for the distillation. Your remaining cold gives the nitrogen-rich fraction and in the heat exchangers 5 and 2, after which it leaves the system via line 32. The low nitrogen Fraction that, depending on how far you go with the rectification, also almost pure Methane can be, is withdrawn in liquid form from the foot of the column 4 via line 20. The major part of the bottom product then passes through the line; 33 to the pump 21, in which it is compressed to a higher pressure, e.g. to the pressure of the entering Natural gas of over 35 atm. After the release of cold in the heat exchanger 2, it leaves the System via line) 4.

Ein Teilstrom des Sumpfproduktes wird über Leitung 35 abgezweigt und in den Wärmeaustauschern 5 und 9 tiefgekühlt. Dieser Teilstrom dient als offener Kreislauf zur Rücklauferzeugung im Kopf der Kolonne 4. Er wird im Entspannungsventil 25 vom Kolonnendruck, etwa 30 atü, auf ca. 2 ata entspannt. Er verdampft im Wärmeaustauscher 26, wodurch # Rücklauf für die Rektifizierkolonne 4 erzeugt wird. Durch Leitung 56 gelangt die annähernd drucklose stickstoffarme Fraktion in die Wärmeaustauscher 9 und 5, in denen sie sich gegen die abzukühlende flüssige Sumpffraktion erwärmt. Im Wärmeaustauscher 37 wird das Kreislaufmedium auf Umgebungstemperatur gebracht und anschließend im Kompressor 22 wieder auf Kolonnendruck verdichtet. Nach !)urchlaufen des Wasserkühlers 25 und des Wärmeaustauschers 5 gelangt das Kreislaufmedium schließlich als Dampfauftrieb @urück in die Kolonne 4. Der Kompressor 22 kann selbstver.'t?ndlich auch kalt eingesetzt werden. Ferner kann er durch Fremdenergie zusätzlich antrieben werden, falls der Stickstoffgehalt im Erdgas nur gering ist. Die Entspannung der stickstoffreichen Fraktion kann auch mehrstufig durchgeführt werden. Selbstverstcrindlich kann der Kreislauf auch geschlossen ausgeführt werden und unter einem anderen Druck als dem Kolonnendruck betrieben werden. Dies ist besonders dann empfehlenswert, wenn man als Sumpfprodukt ein möglichst reines Methan erhalten will, welches nicht durch andere Beimengungen verunreinigt sein soll.A substream of the bottom product is branched off via line 35 and frozen in the heat exchangers 5 and 9. This partial flow serves as an open one Circuit for generating reflux in the head of column 4. It is in the expansion valve 25 from the column pressure, about 30 atü, relaxed to about 2 ata. It evaporates in the heat exchanger 26, whereby # reflux for rectification column 4 is generated. By line 56, the almost pressureless, low-nitrogen fraction enters the heat exchanger 9 and 5, in which it warms up against the liquid bottom fraction to be cooled. In the heat exchanger 37, the circulating medium is brought to ambient temperature and then compressed again to column pressure in the compressor 22. After!) Run through of the water cooler 25 and the heat exchanger 5, the circulating medium finally arrives back into the column 4 as steam buoyancy. The compressor 22 can of course can also be used cold. It can also be powered by external energy if the nitrogen content in the natural gas is only low. The relaxation of the nitrogen-rich fraction can also be carried out in several stages. Of course the circuit can also be run closed and under a different pressure operated as the column pressure. This is particularly recommended if you want to get the purest possible methane as the bottom product, which is not should be contaminated by other admixtures.

Fig. 2 zeigt. eine Abwandlung des Verfahrens von Fig. 1. Das Erdgas in Leitung 1 wird nach Durchlaufen des Verdamprers 3 im Drosselventil 7'zunächst auf einen Druck, der gleich oder höher ist als der Kolonnendruck, entspannt, wobei es sich zum Teil verflüssigt. Im Abscheider )8 wird die flüssige Phase von der gasförmigen Phase abgetrennt. Die flüssige Phase gelangt durch Leitung 59 und Ventil 40 auf verhältnismäßig hohen Temperaturniveau in die Kolonne 4. Die gasförmige Phase, die bereits etwas an Stickstoff angereichert ist, gelangt durch Leitung 41 in den Wärmeaustauscher 42. Hier wird sie durch Kälte verflüssigt, die bei der arbeitsleistenden Entspannung der stickstoffreichen Fraktion in der Turbine entsteht. Uber Ventil 45 gelangt die Flüssigkeit auf verhältnismäßig tiefen Temperaturniveau in die Kolonne 4. Sie bildet dort einen Teil des für die Destillation erforderlichen Rücklauf.Fig. 2 shows. a modification of the process of FIG. 1. The natural gas in line 1 after passing through the evaporator 3 in the throttle valve 7 ' to a pressure which is equal to or higher than the column pressure, where it partially liquefies. In the separator) 8 the liquid phase is separated from the gaseous Phase separated. The liquid phase passes through line 59 and valve 40 relatively high temperature level in the column 4. The gaseous phase, the is already somewhat enriched in nitrogen, passes through line 41 into the heat exchanger 42. Here it is liquefied by the cold, that of relaxation during work the nitrogen-rich fraction is produced in the turbine. Via valve 45 the Liquid at a relatively low temperature level in the column 4. It forms there part of the reflux required for the distillation.

Die zuletzt beschriebene Verfahrensweise kann auch abgewandelt werden, indem das Erdgas nach Durchlaufen des Verdampfers 3 entspannt wird, ohne das es sich verflüssigt. Danach wird es aufgeteilt, ein Teil strom gelangt direkt in die Kolonne 4, der andere Teilstrom wird durch die bei der arbeitsleistenden Entspannung der stickstoffreichen Frakticn entstehende Kälte verflüssigt und im oberen Teil der Kolonne als Rücklauf aufgegeben.The procedure described last can also be modified will, in that the natural gas is expanded after passing through the evaporator 3 without it liquefies. It is then split up, and part of the current flows directly into the Column 4, the other substream is through the work-performing expansion The cold resulting from the nitrogen-rich fraction is liquefied and in the upper part abandoned the column as reflux.

Claims (1)

A n s p r ü c h e Expectations Verfaren zur Zerlegung von stickstoffaltigem Erdgas in eine stickstoffarme und eine stickstoffreiche Fraktion durch einstufide Destillation in einer Kolonne, wobei der für die Destillation erforderliche Rücklauf durch arbeitsleistende Entspannung zumindest des größten Teils der sttickstoffreichen Fraktion und durch Verdampfen eines Kreislaufmediums erzeugt wird, nach Patentanmeldung P 20 22 9.54.3, dadurch gekennzeichnet, daß die durch Verdampfen des Kreislaufmediums entstehende Kälte a Kolonnenkopf und die durch Entspannen der stickstoffreichen Traktion entstehende Kälte unterhalb des Kolonnenkopfes auf einen höheren Temperaturniveau zur Erzeugung von Rücklauf dient. Process for the decomposition of nitrogen-containing natural gas into a nitrogen-poor one and a nitrogen-rich fraction by single-stage distillation in a column, the reflux required for the distillation by work-performing expansion at least most of the nitrogen-rich fraction and by evaporation a circulating medium is generated, according to patent application P 20 22 9.54.3, thereby characterized in that the cold resulting from evaporation of the circulating medium a top of the column and the resulting from relaxation of the nitrogen-rich traction Cold below the top of the column to a higher temperature level for generation of return serves. 2, Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der höchste Druck des Kreislaufmediums gleich dem Kolonnendruck ist.2, method according to claim 1, characterized in that the highest Pressure of the circulating medium is equal to the column pressure. 3. Verfahren nach anspruch 1 oder 2, dadurch gekennzeichnet, daß das zur Zerlegung bestimmte Erdgas, nachdem es den I'olonnensumpf beheizt hat, auf oinen Druck entspannt wird, der gleich oder größer ist als der Kolonnendruck, wobei es sich zum Teil verflüssigt, wonach der gasförmig gebliebene Teil des Erdgases zumindest weitgehend durch die bei der arbeitsleistenden Entspannung der stickstoffreichen Fraktion entstehende Kälte verflüssigt und als Rücklauf oberhalb der aufgabestelle des zuvor bereits verflüssigten anderen Teils des Erdgases in die Kolonne geleitet wird.3. The method according to claim 1 or 2, characterized in that the natural gas intended for decomposition after it has heated the column sump on oinen Pressure is released, which is equal to or greater than the column pressure, whereby it partially liquefied, after which the gaseous part of the natural gas at least largely due to the relaxation of the nitrogen-rich in the work-performing process The resulting cold fraction is liquefied and used as a return above the feed point the previously liquefied other part of the natural gas passed into the column will. 4. Verfahren nach Anspruch 1 oder 2, dadurch 0'ekennzeichnet, daß das zur Zerlegung bestimmte Erdgas, nachdem as den Kolonnensumpf beheizt hat, auf einen Druck entspannt wird, der gleich oder größer ist als der Kolonnendruck, ohne das eo sich bei dor Rntspannung verflüssigt, wonach es in zwei Teilströme aufgeteil wird, von denen der erste direkt in die Kolonne (4) geleitet wird, während der zweite durch ddie bei der arbeitsleistenden Entspannung der stickstoffreichen Fraktion entstehende Mälte verflüssigt und oberhalb der Aufgabestelle des ersten Teilstromes in die kolonne geleitet wird.4. The method according to claim 1 or 2, characterized in that the natural gas intended for decomposition after it has heated the column bottom a pressure is released, which is equal to or greater than the column pressure, without the eo liquefies when the tension is released, after which it is divided into two partial flows , of which the first is fed directly into the column (4), while the second by the work-related relaxation of the nitrogen-rich The resulting fraction is liquefied and above the feed point of the first Partial stream is passed into the column. 5. Verfahren nach einen der Ansprüche -1 bis 4, dadurch gekennzeichnet, daß der Kreislauf offen ist und als Kreislaufnedium ein Teil der methanreichen Fraktion dient.5. The method according to any one of claims -1 to 4, characterized in that that the cycle is open and a part of the methane-rich fraction as a cycle medium serves. 6. Verfahren nach einen der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß bei ausreickenden Stickstoffgehalt im Erdgas der Kreislaufverdichter ausschlie@lich durch die bei der arbeitsleistenden Entspannung der stickstoffreichen Fraktion frei werdende @nergie angetrieben wird.6. The method according to any one of claims 1 to 5, characterized in that that if the nitrogen content in the natural gas is sufficient, the circulation compressor will only work by releasing the nitrogen-rich fraction during the work-performing relaxation future @nergy is driven.
DE19702055229 1970-05-12 1970-11-10 Natural gas fractionation - into low and high nitrogen fractions Pending DE2055229A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0481497A1 (en) * 1990-10-18 1992-04-22 Praxair Technology, Inc. Separation of nitrogen and methane with residue turboexpansion

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0481497A1 (en) * 1990-10-18 1992-04-22 Praxair Technology, Inc. Separation of nitrogen and methane with residue turboexpansion

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