DE2036105A1 - Gas liquefaction process - Google Patents

Description

DR. KURT-RUDOLF ElKENBERG

j ^ PATENT ADVOCATE

• HANNOVCH · SCHACKtTRASSI 1 · TtLEPON «0811)« 140 ·· 'KALEL PATENTION HANNOVER

Institute of Gas i'eohnology 246/45

Gas liquefaction process

The invention relates to improved methods for liquefying gases.

The method according to the invention-is-in-particular suitable for the liquefaction of natural gas * äae mostly aue. Methane is made up of »heavier hydrocarbons such as ethane, propane, butane and the like can contain. However, from the following description it follows

10 08 US /

suggest that the inventive method for liquefying a large range of normally gaseous Substances can be used * in-which the in this System, coolant components used accordingly to be selected.

It is generally known ₉ that the transition from the gaseous state to the state is about 1/600 of its volume atai:

the natural gas in the liquefied Zmstan 'and stored kana _a Aue this liehe Anstreagiiögea uBttsaoraaea W2? d @ a _ö to TerfaJiren aur ^v ¥ erflissigöag from latßE'gae to vax? fe

ame me® &"ϊ㧮η ₀ Bsrso siae feasiert on lonely

tension canoe «v? ob @ i ei © Yes

the i'efflperatur 8IgIIt ₉ "to @ia moist <whereby the condensed® part fob d © m teoekeasa ßaariiekstand are separated kanoo The last ©!? © ¹ kaaa den and with additional gas daroö, the expaasioassystem Daa compressed gas [email protected] usually with a coolant ₉ um & i® I @ apr © i 'and the Gaa
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step

The other main type of gas liquefaction system is a cascade system that is based on use of heat exchangers, which are continuous are arranged to reduce the temperature of the gas to a liquefaction temperature. At this tempe-. rature turns all gas into a liquid state

■ convicted. Heat exchange for cooling is generally carried out while the gas is under one slightly higher pressure than atmospheric pressure, with the phase transition under a higher and easier accessible temperature level occurs. Bas compressed and liquefied gas is then brought to a lower pressure suitable for storage and transportation is. During the pressure reduction, some of the liquid evaporates as a gas with an accompanying reduction the temperature.

The selection of the cascade circuit or an expansion circuit for the liquefaction depends on a number of Paktoren such as & βτ composition of the gas, the energy requirements, which for the liquefaction arrangement available .stehenden room, die.Kosten the raw material, the type of the liquefaction plant and the like .

j. The inventive method corresponds to from Principle of a cascade system, however, there are essential

109 813 3

There are improvements over the classic cascade circuit or over the newer: >., so-called combined cascade circuit, which uses only one compressor. In the case of the lower system, the coolant components such as propane, ethane and butane are kept separate as individual components or flows in the cooling circuit of the system and in storage. Consequently, this system requires a substantial expenditure of energy for condensing this KUhlmittelkomponenten _f in order to maintain the effectiveness of the system. According to the present! Invention, the coolant components are mixed with one another and, after compression, according to one embodiment of the invention, mixed with the natural gas in the process stream «Then the coolant components are separated into individual streams with essentially pure components, which are fed to the system as liquid streams« According to a second embodiment of the In accordance with the invention, the coolant components are separated into individual streams with different mixtures of the components. The cooling takes place by successive evaporation of the cooled, liquid component streams into a gas stream, which after the evaporation of the individual, cooled, liquid component streams (pure or mixed) into it, forms the mixed coolant component stream and is returned to the compressor. With this arrangement, only a single stage compressor is required, and the required compression energy is approximately 40 # lower than that

109808/1358

2 O 3610

Compression energy required for a classic cascade cycle necessary is"

The method according to the invention can be used both for the initial liquefaction of natural gas the feeding, storage or transport and reliquefaction of itfaturgasdampf used that evaporate during storage. Basically, in the cascade and in the included Cascade system the vaporized gas and the purge gas either released to the atmosphere, compressed in a second compressor or used as fuel. When it's let out to the atmosphere or used as fuel, the stored gas can have an excess of heavy hydrocarbons and not be suitable for general distribution. If it is in a wide Compressor compressed and returned to memory t, both the system and the energy costs become higher. With the system of the present Invention, the vaporized gas and the purge gas can be recycled and combined with the feed stream and so fed back to the storage tanks, so that no additional systems are required and the concentration of the stored gas is kept essentially constant.

109808/1358

Accordingly, it is an object of the present invention to provide an improved liquid fluid sealer for gaseous material
Aim, an improved fluidity

liquefaction or reliquefaction by natural gas. watch.

! Another object is an improved Daria ₉

; To indicate the liquefaction system _f that simple. in its

j construction and economical and effective in its

: Working method is.

It is also another goal to provide an improved liquefaction system. in which the coolant components a compressor as a mixed stream, which after compression is divided into individual streams which enter the system as fluid currents »

Still another object is to provide an improved liquefaction system in which essentially less compression energy than necessary with similar systems is. , ....

Other objects and features of the invention are partly obvious and will be for the other part below to be discribed"

, The invention includes! Steps and relationships Steps in the Hinbliok on dlo are explained in a playful way.

© in one or more such other steps © »This is done at ¹

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Further details of the invention are provided below
described in more detail with reference to the drawings in exemplary embodiments. In the drawings shows:

Fig. 1 shows an embodiment of the invention
illustrative flow diagram,

Fig. 2 and 3 parts of flow diagrams,

represent modifications of the invention,

Fig. 4 shows a second embodiment of the
Invention flow diagram and

5 shows part of a flow diagram,

this is a modification of the design
according to Fig. 4 represents.

According to FIG. 1, a natural gas stream 56 is under a high pressure and at a temperature which is achieved by water cooling
is reachable, entered into the system. This natural gas stream is preferably fed to a methane separator 21 of a stripper, in which it is combined with a condensed, mixed - ■ coolant stream 55, which, as will be explained in more detail below ^;

109808/1358

is described, νοίί a multi-stage compressor 30 is derived. As an alternative to this, the natural gas stream 36, if it consists essentially of pure methane, can be entered directly at the inlet of a heat exchanger 10, as indicated by the flow curve 26. In the example shown, it is assumed that both the natural gas stream 36 as well as the condensed, mixed coolant stream 55 under a pressure of 42 <, 2 kg / cm .a. stands and has a temperature of 21.1 ⁰ C "However, if desired, different pressures and temperatures can be used and the system modified accordingly."

The stripper 20 can be of the conventional type used for fractional distillation, using some hydrocarbons in a total cyclic reflux with heat dissipation in the. Rüeklsiifteosiclesisor each lolonn® ■ and a heat supply in the Aufkociier each column "In the example shown, the various columns of the stripper 20 consist of the methane separator 21, an ethane separator 22 ₉ a propane separator 23s" a butane separator 24 and a pentane separator 25? where, jsdes the separator has a return condenser 68 and a reboiler 69 »

The methane separator '21 brushes the! © than from the condensed, mixed. Coolant flow 55 and the natural gas flow 36 aTb _r so that © in im

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substantially pure, liquid methane stream 40 for the liquefaction cycle is delivered. Most of the heavy constituents in the natural gas stream are from the return stream 62 of the heavy components added, with the cooling capacity for the condensation of the essentially pure, liquid methane stream 40 is reduced in the liquefaction cycle.

The methane stream 40 is cooled progressively in the liquefaction cycle within the heat exchanger 10 to 17 in such a manner that it has -157 ⁰ C a pressure of about 42.2 kg / cm a »and a temperature as it exits from the heat exchanger 17th This is described in more detail later. It can then be entered under pressure into a storage tank, but it is preferably expanded by a throttle valve 41 to a storage pressure which is usually close to atmospheric pressure and, in the example shown, 1.05 kg / cm a. is assumed, and divided into a liquid stream 42, which is fed into the storage tank 18, and a gaseous methane stream 43. Both streams have a temperature of approximately -162 ⁰ O.

The gaseous methane stream 43 is combined with the liquid ethane stream 58 described below, whereupon these two streams with the mixed coolant stream are combined by each of the heat exchangers 10 to

036105

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passes tufenkompressör the Increase xfird fed 50 ₀ Latter-end "all © individual Kühlmittilkomponenten be combined with the current 50 ^ before ai @ st the Sfetestufenkompressor 30 fed _β Jtemsufolge i © r Btroa 50 is referred to as mixed Kühlmitteleteoia 50". The gaseous Methanation 43 acts as a carrier for the individual coolant components; which are _{absorbed 9} by being evaporated in the mixed coolant flow 50 Ii ine the coolant flow 50 thus acts as an effective working medium for the heat exchanger System® "As a result, it is necessary for a pertinent mode of operation - & Systems that a gaseous methane flow is coupled and combined with the mixed coolant flow 50", This gaseous methane flow can be conducted in a otseiibeiotaiefeones manner, or alternatively, it came about ? j®äo © h ataoh by coupling the evaporating component from the storage tank 18 with the mixed coolant channel © !! stia © Amfgatxs © rfüllo Έβ understands you for that

dee methane in de
-can·

231 ©
I.
, the heat exchangers 1

■ run reaches j, where "b © i © ia run. © ia IButasÄrsislaiäf

is "everyone iies © ^ Ateühlix ¹ liquid chair-aid compoa.

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this circuit is designed in such a way that it lowers the temperature of the liquid methane stream 40 in the area where it can operate with the greatest efficiency.

Specifically speaking, the ethane circuit comprises the liquid ethane stream 58 which passes through each of the heat exchangers 10 to 17 from the ethane separator 22 of the stripper 20. When passing through this heat exchanger, the pressure of the ethane stream 58 is essentially at a constant pressure of 42.2 kg / cm a. held, whereby it progressively in the individual heat exchangers to -17.8 ⁰ C, -45.6 ⁰ O ₁ -56.7 ⁰ C, -73.7 ⁰ C, -95.6 ⁰ C, -107 ° 0, -118 ⁰ G and -157 ⁰ C is cooled. After leaving the heat exchanger 17, the cooled, liquid ethane stream is passed through the throttle valve 67 to a pressure of 1.05 kg / cm a. and a 'temperature of -159 ⁰ G relaxed and combined with the gaseous methane stream 43. As already described, both of these streams are combined with the mixed coolant stream 50 before they enter the heat exchanger 17. The heat of evaporation of the cooled, liquid methane is absorbed into the mixed coolant stream 50 during evaporation. When the latter is heated from -159 ⁰ O to -118 ⁰ G in the heat exchanger 17, and causes the cooling in the heat exchanger 17. Sin part of the cold, liquid ethane stream 58 is coupled to the outlets of the heat exchangers 14 »15 and 16 with the mixed coolant stream 50 and combined. The cold, liquid ethane stream 58 at the outlet of the heat exchanger 14

109808/1353

has a pressure of 42.2 kg / cm a · and a temperature of -95 »6 ⁰ C, with the part of this flow, which is coupled to the mixed coolant flow 50, through the throttle

valve 70 to a pressure of 1.05 kg / cm a. is relaxed. This cold liquid Äthanstrom which is combined with the mixed refrigerant stream 50, "causes 14" if it is vaporized into the mixed refrigerant stream and warmed from ⁰ -95.6 -73.3 C to ⁰ C ₉ Similarly, the cooling of the heat exchanger the parts of the cold, liquid ethane stream which emerge from the outlets of the heat exchangers 15 and 16 are released through the throttle valves 71 and 72 to a pressure of 1.05 kg / cm a., before they are combined with the mixed coolant stream 50 The cooling of these heat exchangers 15 and 16 is brought about by the evaporation of the cold, liquid stream of ithane, with this changing from -107 ⁰ to -95> 6 ⁰ and from 118 ⁰ to -107 ⁰ in these heat exchangers 15 and 16 heated.

The propane circuit comprises the liquid propane stream 59 which, from the propane separator 23 of the scraper, only passes through the heat exchangers 10 to 13; The liquid ■ propane stream 59 is progressively cooled in these heat exchangers 10 to 13 to -17.8 ⁰ G, -45.6 ⁰ G, -56.7 ⁰ G and -73.3 ⁰ O, while its pressure is essentially constant at

"42.2 kg / cm a. Is held» This cooled, liquid propane stream 59 with a temperature τοπ -73 »3 ⁰ O. is through

the throttle valve 74 to a pressure of 1.05 kg / cm a. ent tension and. combined with the mixed coolant stream-50. As in the pail of the stream of ethane 58, this causes a chilled one liquid propane stream 59 the cooling in the heat exchanger

1-098-0-8 / 4-358

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I when it evaporates in the mixed coolant stream 50 and warms up from -73.3 ⁰ O to ^{-56.7 0} O.

The butane circuit comprises the liquid butane stream 60, which only passes through the first three heat exchangers 10 to 12 from the butane separator 24. This liquid butane stream is progressively in the individual heat exchangers 10 down to ⁰ C -17.8, -45.6 and ⁰ O - ⁰ O 56.7 cooled. The pressure will

, again essentially constant at 42.2 kg / cm a. held.

A {part of the butane stream 60 is at the outlet of the heat exchanger 11 combined with the mixed coolant stream 50,

■ after he has passed through the throttle valve 75 to 1.05 kg / cm a. is relaxed. The remainder of the butane stream 60 is with the

! mixed coolant flow, combined after it has passed the heat exchanger 12 and through the throttle valve 76 to 1.05 kg / cm a. is relaxed. The cooling for the heat exchangers 11 and 12 is brought about by this expanded butane stream when it evaporates in the mixed coolant stream 50 and increases from -45.6 ⁰ O to -17.8 ⁰ O and from ^{-56.7 0} C in the process. 45 »6 ⁰ O in the heat exchangers 11 and

; warmed up. ■

ι The remaining cooling cycle is the pentane cycle. With him an essentially pure, liquid one becomes

Pentane stream 61 at a pressure of 42.2 kg / cm a. and a temperature of 2t, 1 ⁰ O passed from the pentane separator 25 through the heat exchanger 10. When passing the heat exchanger 10, the liquid © pentane stream 61 is on

s -17.8 ° 0 and then cooled through the throttle valve 77 1.05 kg / cm a. relaxed and with the mixed coolant flow 50 united. This cooled pentane stream is in

j evaporated 50 the mixed refrigerant stream and effected at a heating -17.8 ⁰ O ⁰ to 21.1 C, the cooling of the heat exchanger 10 degrees.

10080 & / 1

-14.

Of the . Pentane separator 25 can be made upon request also suitable for generating a hexane-Iefeeostromes be. A product stream made up of heavy components from the bottom of the pentane separator 25 is the return = current 62 of the heavy a Bestaadteil® These heavy constituents are diverted by means of the 63 to a cooler 64, following the aie through the line 65 to the top of the first column separator 21 of the stripper "20", Di © These heavy constituents dissolve with the maturation gas flow 36 and the mixed coolant flow. 55 off the multi-stage compreso.r 30. Darsufhia are all ^ these Stream again in the eagerness of breath separated.

During the course of the Yerflttssigan the cooling coolant flow © mittelstroa 5 stands and urprüo

i®v is' lfssgl ®i © h. with

I eisehea Kaslsi

! energy eiee

p vi® "b® *

with a pressure of 1.05 kg / cm a. and a temperature of 21.1 ° C. The mixed coolant flow 50 is in the multistage compressor 30, which comprises the compressor stages 31 to 34, to a Dr ¹ UOk of 42.2 kg / cm a. compressed and condensed in water-cooled condensers 35 between the individual compressor stages. The compressed, mixed coolant stream 55 from the multistage compressor 30 is fed to the top of the first column or to the top of the methane separator 21 of the stripper 20, in which it is separated in the manner described. ■

The composition of the liquid methane stream 42 supplied to the storage tank 18 can be regulated by removing the amounts of heavy constituents that are condensed in the heat exchangers 10, 11 and 12. These separated liquids are coupled to the mixed coolant stream 50 from the methane stream 40 by lines 45 to 47. There are throttle valves in the lines 45 and 46; and 52 { the flow in line 47 is expanded through the throttle valve • 76) to throttle these heavy, fluid

■

, sigen components to a pressure of approximately 1.05 kg / cm a. j provided. Remove these three streams effectively everything propane, butane, pentane and heavier hydrocarbons, all of the methane stream 40, although the total ^amount: NEN these heavy components in allgemcL is very low.

When the ethane component of the liquid methane stream 42 is lowered below the level of the methane flow 40: if the heat exchanger 14 is to be used, as shown in FIG.

109808/1358

shown, divided into two separate heat exchangers 14 and 14 '. The first heat exchanger 14 cools then the methane stream 40 from -73.3 ° C. to -81.7 ° C. A liquid stream 27 rich in ethane can then be separated off .be, whereupon the methane stream 40 is then cooled to -95f6 ° C in the second heat exchanger 14 ' * This ethane-rich liquid flow 27 can also be combined with the 1thane flow 58, before the latter enters the heat exchanger 15 « whereby cooling to the lowest possible temperature is achieved.

If helium is to be recovered from methane stream 40, a high pressure separator is used (not shown) between the outlet of the heat exchanger 17 and the throttle valve 41 are provided. The gas separated in this heat exchanger contains everything in that Matsrgasstrom 36 available helium »This helium can can only be obtained as a very valuable by-product with this type of cycle.

When the natural gas stream 36 is rich in heavy hydrocarbons such as ethane, propane, jutane. . and the like «. is, a product stream of these valuable liquids can be withdrawn from the individual coolant _{component streams 58 to 61 f} if the inventory of each of these components is higher than it is necessary for the liquefaction system.

109-808 / 1-358

- Changes in the composition can be similar of the natural gas stream 36 the necessary amount each of the individual coolant components in the cooling circuit change, these changes within the cycle through recovery of the component can be carried out from the natural gas stream.

As previously indicated, the vaporized gas from the storage tank 18 can return to the storage tank after having passed through the cooling system is. The gas stream .28 becomes with the gaseous methane stream 43 combined and then fed to the mixed coolant flow and in the manner described through the cooling circuit led * As a result, no additional compressors are necessary and the concentration of the stored gas remains relatively constant.

Pigf 3 shows a further modification that can be used in the liquefaction cycle described to produce supercooled, liquid natural gas, natural gas in slushy or natural gas in a solid state. This modification provides for the use of an additional heat exchanger 19 and separators. The coolant composition is also changed here by providing nitrogen, helium and / or hydrogen and hydrocarbons. The condensed feed stream 40 from the heat exchanger 17 exits as stream 80, which is a mixture of gas. and there is liquid. This stream 30 becomes in this

109808 / 13Si

= 18 «

Pall fed to a separator 81. The gas stream 82 coming from the separator 81 contains most of the nitrogen and helium of the feed stream 40 and is further cooled in the heat exchanger 19. » The liquid flow coming from the separator 81 is also further cooled in the heat exchanger 19, then expanded to feeder pressure through the throttle valve 84 and fed to the supply duct 18 «. The liquid stream 85 can be either a supercooled liquid or a mixture of liquid or solid natural gas exist, so matsehförmige Koaeieteaz possess any dissolved gas which is liberated in the final flash _t "can be used wardens, umd.nen pressure over the Speieherflüseigkeit wherein excess SSAS recycled through the 19 86 Uird _$ vq ®B then vereiaigt with the coolant flow 50

82 tiisä using ias Ifeosselt®Bfe ils

83 on an Iteuek v @ n I ₀ 05 feg- / eiao sötspaaat unä daaaeh Eiat @ s ^j lrilJil-fees ₀ liquid mead 89 aias_ the storage tank 18 g & g @ £ ügt _e Di® ¥ @ räaisp £ ößgäi @ ses cooled , liquid! © tiisss 89 in 'den nitrogen or Stiskstoff-WaesQretoff ^ ßassti ¹ © ® 82 tewirfet the cooling in äea terffitasstausehtE Ϊ9ο Di® Iteigsi. '«Ygi des

The nitrogen and the helium or the nitrogen and the hydrogen run back into the feed stream 40 and can be separated again in the separator 81 " The selection of the separation temperature depends on the special mixture that is used and Bioh refers to a phenomenon called reverse solubility is known that occurs with hydrogen and helium at low temperatures As it approaches its point of strength, the amount of helium or hydrogen that can be dissolved instead decreases to get bigger like normal, and it is possible already a complete separation especially at temperatures below -157 ° C.

The one in Pig. 5 circuit shown can also be modified in that the throttle valve 84 the flow to a selected lower pressure of, for example, 21.1 kg / cm a. relaxed, and that one Outflow line 100 and another throttle valve 10V is provided. The outflow line 100 is before the connection of the throttle valve 101 to the outlet of the throttle valve 84 connected so that nitrogen, hydrogen or helium and methane gases at the lower pressure for others Purposes can escape if so desired. The throttle valve 101 then relaxes the flow except for Memory pressure before ei? is passed into the storage tank 18.

Ibt Pig. Figure 4 is an apparatus formed in accordance with another preferred embodiment of the invention shown for the liquefaction of natural gas. This again-

109808/1358

given system requires essentially the same cooling energy as the previously described system, his simplified and reduced fractionation arrangement however, it offers significant economic advantages.

In this system there is the natural gas flow supplied 125 consists essentially of pure methane and is supplied to the system under a high pressure and temperature which can be achieved by water cooling, supplied. The pressure and temperature are, for example, 42.2 kg / cm a. and 21.1 ° C. This natural gas flow becomes progressive in the heat exchangers 130 to 135 in such a manner cooled so that it is approximately .under a pressure of 42.2 g / cm a. and with a temperature of 21.1 ° C on the heat exchanger 135 exits. This is described in detail below. The natural gas flow can then be fed into a storage tank under pressure 136 must be entered. However, it is preferably depressurized to an accumulator pressure by a throttle valve 137 which is usually close to atmospheric pressure, and in the example shown at 1.05 kg / cm a. lie β) 11. He is then also in a stream of liquid 138, which is entered into the storage tank 136, and -in / a gas stream 139 separated. Both of these streams are at a temperature of approximately -162 ° G. This gas stream 139 is combined with a gas stream 140, which is used as fuel to drive the turbines (not shown) of the Multi-stage compressor 141 is used.

The fractionation arrangement of this system has been greatly simplified compared to the scraper 20 in the system shown in FIG. this

is evident from the following description. The mixed refrigerant stream 160 is fed from the multistage compressor 141 to a still 142 at a pressure of 42/2 kg / cm a. forwarded. At the top of the distillation apparatus 142, a steam stream 161 consisting predominantly of methane and ethane is generated at a pressure of 42.2 kg / cm a. and a temperature of approximately 6.67 ° C and fed to the heat exchanger 131. After exiting the heat exchanger, the steam stream 161 has a temperature of approximately -14.4 ° C. Here, a stream 162 of methane and Δthane in a ratio of approximately 3 t 1 is stripped off and returned to the top of the still 142 by means of a pump 163 The remainder of the stream 161, which now consists of equal parts of ethane and methane, then passes through the heat exchangers 132 to 135 and on leaving the heat exchanger 135 still has essentially the same pressure of 42.2 kg / cm a., but has cooled to a temperature of -157 ° C. The stream 161 is now expanded to a pressure of 1.05 kg / cm a »and a temperature of -162 ° C by means of the throttle valve 164 and combined with the coolant stream 160, which is fed to the multistage compressor through the heat exchangers 135 to 130» Stream 161 is a gaseous stream, which consists essentially of equal amounts of methane and ethane and, like the previously described gaseous methane stream 43, serves as a carrier for the individual mixed coolant streams, as already described above * This gaseous stream also sees a gaseous stream, which ensures the effectiveness of the heat exchangers of the system. '

The bottom of the still 142 is made up primarily of ithan and is passed as a stream 166 through a heater 147 '. After exiting the heater 147 ", part of the stream 166 is fed back into the still 142 via the line 167. The remainder of the stream 166 consists mainly of ethane and butane a Draals vm 42.2 kg / one e · as stream X68 a Deetillitrappswat W

The vapors leaving the head of the still 145 are fed in a stream 16 to a cooler 150, in which part of the stream condenses and as stream 170 2SUrUeIi: into the still 143 runs to the permanent rope of the Stroraea Feesteht present aias is as current 171 through the heat accumulator 130 conducts, .in deoeii qt

from the heat exchanger 134, a temperature won -95 "6 ° 0 _e besitzt® This cooled © © ₉ now liquid stream is duroh the throttle valve 189 to a entspanat" DsiiQk tob X ₅ Q§ kg / cm a., and the g @ mis © ht @ s KÜhlmittelsteo® 160 united «The heat of evaporation © of the cooled liquid stream 171 is absorbed fob the mixed coolant stream- '160 during evaporation,) if a @ g letistere.; Voa-95t6 <to -62.2 ° C. in the heat exchanger ¹ 134 is heated and supplies the cooling line of this heat exchanger * 1? 4 ·

The bottom of the still 143 consists predominantly of pentane and Ärtaia sad becomes eis Steoa 175 äurotl · i @ o ^; Heat exchanger 148 routed to Eia i'til d®e S1 to the still 14]
The remaining leftovers will
a print of 432
"68.4 ° 0. corresponding -

A portion of this stream is stripped relaxed and passed as stream 179 through a cooler 151 which cools it to approximately 26.7 G ^0. It is passed from the cooler 151 through the heat exchanger 130. This liquid flow is cooled to -6.67 ° 0 when passing through the heat exchanger 130 'and then by means of the throttle valve 180 to 1.05 kg / cm a. relaxed. After the expansion, the liquid flow is combined with the mixed coolant flow 160. The heat of vaporization of the cooled liquid stream is absorbed during evaporation in the mixed refrigerant stream 160, the latter is heated from -6.67 ⁰ C ^% θ% ^ · ^^ in the heat exchanger 130 and provides the cooling performance of the heat exchanger 130th (^ / v '£ "Γ'' ¹ ^ v

The remainder of the stream 175 is passed through coolers 144-146 in sequence. In the cooler 144 of the stream is cooled to approximately 61.2 G ⁰ and after the exit from the condenser is another current 181, the j consists mainly of butane, stripped and passed through a cooler j 141 ihiauf approximately 26.7 ⁰ C cools. The stream 181 is then passed through the heat exchangers 130 j and 131. After exiting the heat exchanger 131, '181 has the Flüssigkeistsstrom an approximate temperature of -14t4 ⁰ C. This cooled liquid stream 181 is then expanded by means of a throttle valve 182 and combined with the mixed refrigerant stream 160th The heat of evaporation of the cooled stream is again absorbed during evaporation in the mixed coolant stream 160, the

109808/1358

the latter from -14 »4 ⁰ O to -6.67 ' ⁰ C in the heat exchanger 131 is heated. This results in the cooling effect of the heat exchanger 151

Yet another current 184 is stripped from the current 175 after it has passed through the cooler 145 and is cooled to about 48.9 ⁰ C. This stream 184 also consists predominantly of butane, but includes some pentane. and a small amount of propane and hexane. The stream 184 is cooled in a cooler similar to 153 to a temperature of about 26.7 ⁰ C before it is passed through the heat exchanger 130 to 132. As it passes through these heat exchangers, stream 184 is cooled to approximately -40 ° C. Then he is using the throttle valve

185 to a pressure of 1.05 kg / cm a. relaxed and combined with the mixed coolant flow 160. In this Pail the Yerdampfungswärme the cooled Plüssigkeitsstromes during evaporation in the mixed refrigerant stream 160 is also absorbed, which also heated from -40 ⁰ C to ^"0 14.4 C in the heat exchanger 132 and causing its cooling capacity.

The stream 175 is cooled to approximately 26.7 ⁰ O after passing through the radiator 146 -and then passed as stream 186 through heat exchanger 130 "to 133" This current

186 also consists primarily of butane, but includes a significant amount of propane and smaller amounts of it Ethane, pentane and hexane. Haoh the passage through the heat

109808/1358

Exchangers 130 to 133, the stream 186 is ^{cooled to approximately -62.2 0} O and then by means of the throttle valve 187 to a pressure of 1.05 kg / cm a. relaxed and combined with the mixed coolant stream 160. As Lall in the streams 171, 179 '181 and 184, the Ve is r evaporation heat cooled ITüssigkeitsstromes this "in-evaporation in the mixed refrigerant stream 160 is absorbed, whereby the latter of -62.2 ⁰ C to -40 ⁰ O in the heat exchanger 133 is heated and its cooling effect is effected.

The mixed coolant stream 160 has a pressure of after exiting the heat exchanger 130 1.05 kg / cm a. and a temperature of about 21.1 C * The mixed refrigerant flow is then in the multistage compressor 141 to a pressure of 42.2 kg / cm a. compressed. This multi-stage compressor comprises the compressor stages to 193, between which there are condensers 194 for cooling of the coolant flow are with water. The compressed, mixed refrigerant stream 160 is from the multistage compressor 141 passed to the still 142, in which he is in the described way is separated again. For "prevention a destruction of the compressor stage 192 is a branch line 196 intended for wiping off liquid that is in the compressor stages 190 and 191 forms. Likewise is one another secondary line 197 is provided through the liquid is stripped in the mixed coolant stream, whereby destruction of the compressor stage 193 is prevented.

»26«

If the natural gas flow 125 is considered, it can be seen that it successively τοη 21.1 ⁰ G to -6.67 ⁰ Cj, -14.4 ⁰ C, -40 ⁰ C, -62.2 ⁰ O, -95 » 6 ⁰ O and -157 ⁰ G when it passes through the heat exchangers 130 to 155 and is in a heat exchange with the mixed coolant stream 160 «While this gas stream is being cooled, some of the heavier components are hexane, pentaene and butane τοη him abgeatreift ^ as indicated by the currents from 198 to 200, so that is fed substantially pure methane the storage tank 136 * Wi © is stated above, the current 125 of the after exiting the heat exchanger 135 by means of throttle valve 137 relaxes to a lying in the vicinity of the atmospheric pressure Speioherdruck · with the gas "the vaporized gas from the storage tank 136 may, shaped Methanation are combined 139, the combined subsequently to the stream 140 Wi ^ d _5, if di @ s is desired »

The mixed © coolant flow 160 consists of a mixture of methane, ethane "propane., Butane, pentaa and hexane." These components are, however, present in units of mixed component streams 171, 179, 181, 1-84 and 186, as if, as in the general ^{case of 1} _{PIg 6} 1, they are all one stream of essentially pure components ”When using the mixed Component streams instead of the pure component streams and combination with the mixed coolant stSOHj, ' _: each stream rarely being reached
have the greatest effectiveness

! ·: ■ -27-

Economical door parts in view of the simplified
Fractionation arrangement on.

Ee can also be helium with a j as a by-product

System according to Figure 4 according to the scheme shown in Figure 5;

be won. From this figure it can be seen that j the helium by simply attaching an additional throttle;

valve 202 in series with the throttle valve 137 and attachment j

an outlet line 203 between the two throttle valves,

137 and 202 can be won. . I.

From the above description it can be seen that
the objectives specified in the introduction to the description and in the description of the figures can be achieved, and that
certain changes are possible without affecting the frame! the invention would leave. The drawings should! and the description is only an example and not a limitation
represent the invention.

-Patent claims-

Bm / kä / bö 109808/1358

Claims (18)

Patent claims s ias liquefaction process, ^ is denoted by. Respectively. Gas in a process stream under elevated pressure. Feeding a condensed, mixed coolant component stream under the same elevated pressure as the gas in the process stream, separating the condensed, mixed Coolant component stream to create a plurality of individual, liquid coolant component streams, Cooling each of these individual, liquid coolant component streams, providing a coolant gas stream which approximately the same temperature as the liquefied gas in the process stream, each evaporating of the individual liquid coolant component streams in the coolant gas stream in a heat exchange process the process stream to the gas in the process stream in a cooling the liquid state, compressing and cooling the coolant gas stream after the liquid coolant component streams have evaporated into it in order to remove the condensed, 109808 / -13S8 get mixed coolant component stream. 2. The method according to claim 1, characterized in that the mixed coolant component stream is separated such that a plurality of individual, substantially j pure, liquid coolant component flows arise. j: ■■ - ■ - ■■■ : 3. The method according to claim 1, characterized in that; the mixed coolant component stream thus separated is that a plurality of individual, controlled,; liquid, mixed coolant component flows arise. j 4. The method according to claim 1, characterized in that '■ both the cooling of each of the plurality of individual, liquid refrigerant component streams and the cooling of the gas in the process stream to liquefy it by evaporating the plurality of individual, liquid refrigerant component streams in the Coolant gas flow takes place. 5. The method according to claim 2, characterized in that the gas in the process stream and the condensed, mixed coolant gas stream are mixed with one another and then the mixture is separated such that the majority of the individual, substantially pure, liquid coolant component streams and a feed stream are produced, which is then liquefied. 10980 8/1158 6. The method according to claim 1, characterized in »that 'ί the liquefied gas in the process stream to a lower one Pressure is released so that a liquid gas stream and j a cold, gaseous stream from part of the liquefied j Gas is produced, which evaporates after the expansion, whereby the cold, gaseous flow forms the cooling medium flow. 7. The method according to claim 5 ».dadurc h ^ gek ennzeiohnet _{? Ιι} that the liquefied gas in the process _{stream is expanded to a lower pressure 8} e © that a liquefied gas stream and a cold gaseous stream from a rope of the. Liquefied gas that emerges to represent expansion ,, said cold gaseous stream evaporates the Kühlaitte! forming gas stream, the liquefied gas stream © ine® storage fed-is, and the evaporated gas from äem stored ^ liquefied gas with the cold gaseous stream τβ v & inigt is , ■ 8. The method according to claim 2 _9, characterized in that ^: the gas in the process stream dureh © in® 'saw more! from ■ heat exchangers to convert the gas in the process flow to a liquid state a "bEUküBlea _s a gaseous® »stream of © inem Seil '■ of the liquefied gas in the process stream see below ₈ which evaporates after the expansion» the cold @ ₉ gaseous® stream forms the coolant gas stream ₉ each of the individual ^ - essentially pure, liquid coolant component streams passed through predetermined ones of the plurality of heat exchangers j through which the gas in the process stream passes is directed to the individual, essentially pure ^,! to cool liquid coolant component streams, each of the individual, essentially pure liquid coolant | component flows relaxed to a low pressure and in; the coolant gas flow in a heat exchange process with! the process stream is relaxed in order to cool down both j for liquefaction of the gas in the process stream as j also for the individual, essentially pure, liquid coolant component streams. 9. The method according to claim 8, characterized in that the gas in the process stream and the condensed, mixed Coolant gas stream mixed with one another and then this mixture is separated to produce the majority of the individual, im obtain substantially pure liquid coolant component streams and a feed stream which thereafter liquefies will. 10. The method according to claim 9, characterized in that the gas evaporated from the liquefied, stored gas is combined with the cold, gaseous stream. 109808/1358 -52- 11. The method of claim 8, gekennz characterized eichnet "that the individual, substantially pure, liquid coolant component streams are expanded and evaporated in the coolant gas stream at a point of Abkühlkreislaufes to which each of them the greatest efficacy for the desired cooling has. 12. The method according to claim 8 _f, characterized _f that the heavy components are removed from the gas in the process stream, which are condensed in predetermined by the plurality of heat exchangers and are expanded and evaporated into the coolant gas stream. 13 »Method according to claim 1, characterized in that that the composition of the condensed, mixed refrigerant component stream comprises nitrogen and helium, the gas in the process stream at a predetermined The intermediate point of the cooling cycle is relaxed to a lower pressure, the nitrogen and the helium from separating the gas in the process stream after depressurizing the process stream, the gas in the process stream cooled to a lower! temperature becomes the further cooled gas in the process stream is expanded to a reduced pressure and entered into a storage tank from the gas in the process ^ current separate nitrogen and helium is cooled, this further cooled nitrogen and helium is reduced to one Pressure is released, the subcooled, liquid gas from the storage tank with the released nitrogen and helium 109808/13 ^ 8 combined wirdf the resulting Meohung with the refrigerant gas stream in heat exchange with both the and the gas in the process stream, after which the helium and nitrogen is separated from it, is vaporized by the gas in the process stream separate nitrogen and helium, 14. The method according to claim 1, characterized in that the composition of the condensed, mixed coolant component stream comprises nitrogen and hydrogen, the gas in the process stream at a predetermined intermediate point in the cooling cycle ;. a reduced pressure is released, the nitrogen and hydrogen are separated from the gas in the process stream after the depressurization of the process stream, the gas in the process stream is cooled to a lower temperature, the further cooled gas in the process stream is expanded to a reduced pressure is fed into a storage tank, the nitrogen and hydrogen from the gas in the Vjr? - "■■■ β-". Fahrensetrom are separated, the further cooled nitrogen and hydrogen are expanded to a reduced pressure, the supercooled, liquid gas from the storage tank is combined with the expanded nitrogen and hydrogen, the resulting mixture with the coolant gas flow in heat exchange with both the nitrogen and the hydrogen, the is separated from the gas in the process stream, and the latter is evaporated after the nitrogen and hydrogen have been separated , 2Q361Q5 15 · "A method according to spoke 3, daauroh ^ ^ _L gekennzeiohnet that the mixed Kühlmitteletrom is g®tr®aat * controlled by a first and ssweiten ©» !? liquid ₉ g ~ © mixed under high current Be ¹ KLA © ehalten, is cooled the only © controlled, liquid, mixed © power »Vol. then decompressed to a lower pressure * cold to alnen · gaseous stream to eshalt © B ₉ ^ jofoei this cold" gaseous stream to -Xuhlmittelgasetrom forms? the second * controlled liquid "gemischt® St3? ©» is weitezjgetrBnnt * to dne variety of indiVIdEeIIeQ controlled $, liquid, mixed Klihlmittelkoißf®Q8ßt © aBt.r§mea m erhalten- "dereo ₉ each cooled and a © © feig®® B! ^ ia © k expaodiest in άβΏ Kiihlmittelgasaisröm im ¥ äsa® © B®tiifö®oh - old the driving current is spoiled ₉ um di © cooling both for the liquefaction of the Gaaea is ä®m TtEfstegasstgffla as well as for the cooling iadifidsen ier , g © gt®m®gt @ a ₉ flP, ssigen * mixed IiaiHitt © 12s @ ®f ostatiaitsia © · ata cause « 16.! Learned naeä Anspruoh 15s .fiacUa that the sswe & t®, controlled © ₉ flissig® ₉ the i'renQung a "first liquid _f mixed third stetterteBf the relaxed on a dee * Stromes eiaöi second eL © 2> iiIi ¥ £ iE © li © a ₀ proper geaiseiitei! Kühlfflittiilife ^ a © Tbili © t rope 17. The method according to claim 16, characterized in that each of the individual, controlled, liquid, mixed coolant component flows is expanded and evaporated into the coolant gas flow at a point in the cooling circuit at which the desired cooling is achieved. is obtained with the greatest effectiveness. 18. The method according to Anspruoh 1, characterized in that «that the gas in the process stream is a. Passes through a plurality of heat exchangers in order to cool it down to its liquid state, the liquefied gas in the process stream is expanded to a lower pressure in order to obtain a liquefied gas stream for storage and transport purposes. controlled high pressure liquid mixed flow is provided which is expanded to a lower pressure to obtain a cold gaseous flow forming the refrigerant gas flow, each of the individual controlled liquid mixed refrigerant component flows being passed through predetermined ones of the heat exchangers through which the gas in the | drive stream is guided to cool the individual, controlled, ■ mixed, liquid, coolant component streams, each of the individual, controlled, liquid, mixed j coolant component streams is expanded to a lower pressure j and they are in heat exchange with the process ^: stream in the Coolant gas stream are evaporated in order to effect the cooling both for the liquefaction of the gas in the process stream and for the cooling of the individual, j controlled, liquid, mixed coolant component streams au. ι bm / kä / bö 'V! 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