AU2010214861A1 - Method for removing nitrogen - Google Patents

Method for removing nitrogen Download PDF

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Publication number
AU2010214861A1
AU2010214861A1 AU2010214861A AU2010214861A AU2010214861A1 AU 2010214861 A1 AU2010214861 A1 AU 2010214861A1 AU 2010214861 A AU2010214861 A AU 2010214861A AU 2010214861 A AU2010214861 A AU 2010214861A AU 2010214861 A1 AU2010214861 A1 AU 2010214861A1
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AU
Australia
Prior art keywords
fraction
nitrogen
methane
feed
rich
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
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AU2010214861A
Inventor
Heinz Bauer
Daniel Garthe
Rainer Sapper
Georg Schopfer
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Linde GmbH
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Linde GmbH
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Filing date
Publication date
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Publication of AU2010214861A1 publication Critical patent/AU2010214861A1/en
Abandoned 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
    • F25J3/0204—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
    • 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
    • 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
    • F25J2200/04—Processes or apparatus using separation by rectification in a dual pressure main column system
    • F25J2200/06—Processes or apparatus using separation by rectification in a dual pressure main column system in a classical double column flow-sheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure 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
    • F25J2200/72—Refluxing the column with at least a part of the totally 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/78—Refluxing the column with a liquid stream originating from an upstream or downstream fractionator 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
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/04—Mixing or blending of fluids with the feed 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/42—Processes or apparatus involving steps for increasing the pressure of gaseous process streams 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
    • 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
    • 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
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream 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
    • F25J2280/00—Control of the process or apparatus
    • F25J2280/20—Control for stopping, deriming or defrosting after an emergency shut-down of the installation or for back up system

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

Abstract

The invention relates to a method for removing a nitrogen-rich fraction from a feed fraction which substantially contains nitrogen and hydrocarbons, wherein the feed fraction is subjected to separation into a nitrogen-rich and a methane-rich fraction by rectification. According to the invention and during an interruption of the feed of the feed fraction, the nitrogen-rich fraction (4'') and the methane-rich fraction (5'') are compressed at least temporarily and are jointly fed to the method as a feed fraction, whereby the compression of the nitrogen-rich (4'') and the methane-rich fraction (5'') can be carried out in a separate and/or joint manner.

Description

1 Description Method for removing nitrogen The invention relates to a process for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, wherein the feed fraction is 5 separated by rectification a nitrogen-rich fraction and a methane-rich fraction. A process of the type in question for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons is explained below with reference to the process shown in Figure 1. 10 The feed fraction containing essentially nitrogen and hydrocarbons and which originates, for example, from an upstream LNG plant, is introduced via line 1. It preferably has a pressure of greater than 25 bar and was subjected, optionally to a pretreatment such as sulphur removal, carbon dioxide removal, drying etc. In the heat 15 exchanger El it is cooled and partially condensed against process streams which will be considered in more detail hereinafter. Via line 1' the partially condensed feed fraction is subsequently fed to a preseparation column T1. This preseparation column T1 forms, together with the low-pressure column T2, a 20 double column T1/T2. The separation columns T1 and T2 are thermally coupled via the condenser/reboiler E3. From the bottom phase of the preseparation column T1, via line 2 a hydrocarbon-rich liquid fraction is taken off, subcooled in the heat exchanger E2 against process 25 streams, which will be considered in more detail hereinafter, and subsequently fed via line 2' and expansion valve a to the low-pressure column T2 in the upper region. Via line 3, a liquid nitrogen-rich fraction is taken off from the upper region of the preseparation column T1. A substream of this fraction is added via line 3' as reflux to 30 the preseparation column T1. The nitrogen-rich fraction taken off via line 3 is subcooled in the heat exchanger E2 and fed via the line 3" and expansion valve b to the low pressure column T2 above the feed-in point of the above-described methane-rich fraction.
' \.0 I I L.F 4 IV VUUU I0 2 Via line 4, a nitrogen-rich gas fraction is taken off at the top of the low-pressure column T2. The methane content thereof is typically less than 1% by volume. In the heat exchangers E2 and El the nitrogen-rich fraction is subsequently warmed and optionally 5 superheated before it is taken off via line 4" and released into the atmosphere or optionally fed to another use. Via line 5, a methane-rich liquid fraction is taken off from the bottom phase of the low pressure column T2, which liquid fraction, in addition to methane, contains the higher 10 hydrocarbons contained in the feed fraction. The nitrogen content thereof is typically less than 5% by volume. The methane-rich fraction is pumped by means of the pump P to a pressure as high as possible - this is customarily between 5 and 15 bar. In the heat exchanger E2, the methane-rich liquid fraction is warmed and optionally partially vaporized. Via line 5' it is subsequently fed to the heat exchanger El and in this 15 completely vaporized and superheated against the feed fraction which is to be cooled. By means of the compressor V, the methane-rich fraction is subsequently compressed to the desired delivery pressure which generally corresponds to the pressure of the feed gas fraction in the line 1, and taken off from the process via line 5". 20 Processes of the type in question for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons are implemented in what are termed nitrogen rejection units (NRUs). Separating off nitrogen from nitrogen/hydrocarbon mixtures is always carried out when an elevated nitrogen content 25 impedes the intended use of the nitrogen/hydrocarbon mixture. For instance, a nitrogen content of greater than 5 mol%, for example, exceeds typical specifications of natural gas pipelines in which the nitrogen/hydrocarbon mixture is transported. Gas turbines can also only be operated up to a certain nitrogen content in the combustion gas. 30 Such NRUs are generally similar to an air fractionator having a double column, such as described, for example, with reference to Figure 1, constructed as a central process unit and generally arranged in what is termed a cold box. In the case of large plant capacities, generally a plurality of cold boxes arranged in parallel are used. 35 Depending on the field of use, the availability of an NRU can be of great importance.
3 An obstacle to high availability is the long time period which is required in order to restart the process after a relatively long-lasting outage of the feed fraction (NRU feed gas) containing essentially nitrogen and hydrocarbons. Outages of the NRU feed gas can occur, depending on the upstream processes or plants, several times per year, for 5 example due to the outage of an upstream NRU-feed gas compressor or an upstream LNG/NGL plant. In this context, a distinction must be made between restarting from the warm state (warm start-up) and the cold state (cold restart). The warm start-up is comparatively 10 time-consuming, since all of the equipment must again be cooled to cryogenic temperatures and the liquid levels in the process must be built up. A cold restart after comparatively short outages of the NRU feed gas - these are taken to mean outage times between 1 and 24 h, wherein these depend on the ambient conditions, the size of the cold box, the type of construction and mass of the heat exchangers and also the 15 strategy for cold restart (with/without liquids from the process) - from the cold state, can, in contrast, be carried out relatively quickly. During a stoppage of the NRU, owing to unavoidable insulation losses, warming of the separation column(s) and also the heat exchangers, lines, etc., can occur. After a 20 certain warming time which is determined by the plant size and the ambient conditions, a cold restart is no longer possible. The reason for this is the inevitably occurring impermissible mechanical stresses which occur when the (partially) warmed heat exchangers are charged with cold liquids or gases from the process. In such a case the NRU must therefore be warmed to ambient temperature before a warm start-up can be 25 carried out. In the case of longer outages of the NRU feed gas which can be caused by plant faults or maintenance work, the NRU must therefore be completely warmed before a time consuming warm start-up can be carried out. This procedure can last, in some 30 circumstances, longer than one week. This long warm start-up time is lost as production time and can therefore lead to considerable financial losses. This is the case, in particular, when the NRU is integrated into other plants, the production of which is dependent on the functionality of the NRU; those which may be mentioned by way of example are LNG plants having a combustion gas treatment for gas turbines by 35 the NRU.
4 The object of the present invention is to specify a process of the type in question for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons which avoids the above-described disadvantages. 5 For achieving this object, a process of the type in question is proposed for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, which is characterized in that, during an interruption of the supply of the feed fraction, at least temporarily, the nitrogen-rich fraction and the methane-rich 10 fraction are compressed and jointly supplied to the process as feed fraction, wherein the compression of the nitrogen-rich fraction and the methane-rich fraction can be performed separately and/or jointly. In principle, 3 alternative procedures can be achieved thereby: 15 - mixing the two fractions and subsequent joint compression - separate compression of both fractions and subsequent mixing of the two fractions - separate compression of both fractions, mixing and subsequent joint compression of both fractions 20 Further advantageous embodiments of the process according to the invention for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons which are subjects of the dependent claims are characterized in that 25 - if at least one compressor (methane compressor) which compressses the methane-rich fraction in standard operation to the desired delivery pressure is provided, the nitrogen-rich fraction and the methane-rich fraction are compressed by means of the methane compressor, 30 - if the feed fraction, upstream of the supply into the process, is compressed by means of at least one compressor (feed compressor), the nitrogen-rich fraction and the methane-rich fraction are compressed by means of the feed compressor, and 35 I I/ Il-I J4.J IV'IVVVVJ'J~ I 5 - the nitrogen-rich fraction and/or the methane-rich fraction are compressed using a compressor which is without function in standard operation. According to the invention, during an interruption of the supply of the feed fraction, the 5 nitrogen-rich fraction and the methane-rich fraction are then no longer delivered by the NRU, but are compressed, mixed and supplied to the NRU as substitute feed fraction. The NRU and the process of the type in question can therefore be operated virtually completely in a closed circuit. In principle, certain losses of feed gas must be expected owing to leaks and also pressure-limiting flare controllers. In order to compensate for 10 these losses, a controlled make up stream which is mixed from nitrogen and methane is provided. The process according to the invention for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons and also other 15 advantageous embodiments of the same which are subjects of the dependent claims may be described in more detail hereinafter with reference to the exemplary embodiments shown in Figure 2. The exemplary embodiment shown in Figure 2 differs from that shown in Figure 1 only 20 by the two lines 6 and 7 and also the valves c to f. For implementing the above-described circuit operation, the delivery of the nitrogen rich fraction 4" is interrupted by closing the valve c and the nitrogen-rich fraction, instead, with valve d open is added via the line 6 to the methane-rich fraction. The 25 mixed fractions are compressed in the compressor V to the desired and/or required plant pressure and subsequently, with valve f open - the methane delivery valve e is closed - supplied via the lines 7 and 1 again to the fractionation process. Should a compressor V as shown in Figures 1 and 2 not be provided, a compressor 30 suitable for the circuit operation would be supplied which then would be used exclusively for compressing the two fractions during an interruption of the supply of the feed fraction. If an NRU is integrated in an LNG plant, generally compression of the feed fraction to 35 be supplied to the NRU is provided. The compressor provided therefor can then be 6 used in the procedure according to the invention for compressing the nitrogen-rich fraction and the methane-rich fraction which are combined upstream of the compressor. This advantageous embodiment of the process according to the invention is especially advantageous when a methane compressor V as shown in Figures 1 and 5 2 is not provided. The above-described embodiment, in addition, has the advantage that the feed gas compressor - in LNG plants this is what is termed the end flash gas compressor draws in at ambient pressure. This means that the operating pressure of the low 10 pressure column need not be increased, which, compared with compression of the circulated fractions in the circuit by means of the methane compressor, leads to a smaller effect on the operation of the NRU. Thus, for example, the nitrogen-rich fraction and also the methane-rich fraction taken off from the process continue to meet the product requirements of standard operation, which is not possible when the pressure of 15 the low-pressure column is increased. This fact shortens the transition time between the "interruption operation" and standard operation. By means of the procedure according to the invention, even after relatively long interruptions in the supply of the NRU feed gas, a rapid resumption of standard 20 operation can now be achieved, since the operation of the separation process in the closed circuit is maintained and warming the process or the NRU are thereby avoided. The increased expenditure in terms of apparatus and processing required for the process according to the invention are comparatively small, and so the advantages 25 achieved by the process according to the invention certainly justify this increased expenditure.

Claims (4)

1. Process for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, wherein the feed fraction is separated by rectification a nitrogen-rich fraction and a methane-rich fraction, characterized in 5 that, during an interruption of the supply of the feed fraction, at least temporarily, the nitrogen-rich fraction (4") and the methane-rich fraction (5") are compressed and jointly supplied to the process as feed fraction, wherein the compression of the nitrogen-rich fraction (4") and the methane-rich fraction (5") can be performed separately and/or jointly. 10
2. Process according to Claim 1, wherein at least one compressor (methane compressor) which compresses the methane-rich fraction in standard operation to the desired delivery pressure is provided, characterized in that the nitrogen-rich 15 fraction (4") and the methane-rich fraction (5") are compressed by means of the methane compressor (V).
3. Process according to Claim 1 or 2, wherein the feed fraction, upstream of the supply into the process, is compressed by means of at least one compressor (feed 20 compressor), characterized in that the nitrogen-rich fraction (4") and the methane rich fraction (5") are compressed by means of the feed compressor.
4. Process according to any one of the preceding Claims 1 to 3, characterized in that the nitrogen-rich fraction (4") and/or the methane-rich fraction (5") are compressed 25 using a compressor which is without function in standard operation.
AU2010214861A 2009-02-19 2010-02-02 Method for removing nitrogen Abandoned AU2010214861A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102009009477A DE102009009477A1 (en) 2009-02-19 2009-02-19 Process for separating nitrogen
DE102009009477.6 2009-02-19
PCT/EP2010/000613 WO2010094396A2 (en) 2009-02-19 2010-02-02 Method for removing nitrogen

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AU2010214861A1 true AU2010214861A1 (en) 2011-08-18

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US (1) US20120017640A1 (en)
AU (1) AU2010214861A1 (en)
DE (1) DE102009009477A1 (en)
MX (1) MX2011008233A (en)
NO (1) NO20111247A1 (en)
RU (1) RU2011138229A (en)
WO (1) WO2010094396A2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3012211B1 (en) * 2013-10-18 2018-11-02 L'air Liquide,Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude PROCESS FOR DEAZATING NATURAL GAS WITH OR WITHOUT RECOVERING HELIUM
FR3013818A1 (en) * 2013-11-25 2015-05-29 Air Liquide CRYOGENIC DISTILLATION AIR SEPARATION APPARATUS AND METHOD FOR COLD HOLDING SUCH APPARATUS
FR3034427B1 (en) * 2015-04-01 2020-01-03 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude NATURAL GAS DEAZOTATION PROCESS
FR3110223A1 (en) * 2020-05-15 2021-11-19 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for extracting nitrogen from a stream of natural gas or bio-methane

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19919932A1 (en) * 1999-04-30 2000-11-02 Linde Ag Process for obtaining a pure methane fraction
DE10121339A1 (en) * 2001-05-02 2002-11-07 Linde Ag Process for separating nitrogen from a nitrogen-containing hydrocarbon fraction
FR2825119B1 (en) * 2001-05-23 2003-07-25 Air Liquide METHOD AND INSTALLATION FOR SUPPLYING AN AIR SEPARATION UNIT USING A GAS TURBINE
US7484385B2 (en) * 2003-01-16 2009-02-03 Lummus Technology Inc. Multiple reflux stream hydrocarbon recovery process
FR2904869B1 (en) * 2006-08-09 2008-11-07 Air Liquide UNIT AND METHOD FOR DEAZATING NATURAL GAS

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US20120017640A1 (en) 2012-01-26
RU2011138229A (en) 2013-03-27
WO2010094396A3 (en) 2013-04-18
WO2010094396A2 (en) 2010-08-26
NO20111247A1 (en) 2011-09-14
MX2011008233A (en) 2011-08-17
DE102009009477A1 (en) 2010-08-26

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