US3057168A - Rectification of liquid mixtures boiling at low temperatures - Google Patents

Rectification of liquid mixtures boiling at low temperatures Download PDF

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US3057168A
US3057168A US684359A US68435957A US3057168A US 3057168 A US3057168 A US 3057168A US 684359 A US684359 A US 684359A US 68435957 A US68435957 A US 68435957A US 3057168 A US3057168 A US 3057168A
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column
liquid
foot
head
columns
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Becker Rudolf
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Linde GmbH
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Gesellschaft fuer Lindes Eismaschinen AG
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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
    • F25J3/0252—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 hydrogen
    • 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
    • F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
    • 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
    • F25J3/0238—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 2 carbon atoms 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
    • F25J3/04—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 for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04351—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams 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
    • 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
    • F25J3/04—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 for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04363—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of oxygen
    • 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
    • F25J3/04—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 for air
    • F25J3/04436—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 for air using at least a triple pressure main column system
    • F25J3/04454—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 for air using at least a triple pressure main column system a main column system not otherwise provided, e.g. serially coupling of columns or more than three pressure levels
    • 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
    • F25J2200/08—Processes or apparatus using separation by rectification in a triple 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
    • F25J2200/50—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
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F25J2200/54—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column in the low pressure column of a double 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
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/12—Refinery or petrochemical off-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
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/62—Ethane or ethylene
    • 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
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/20—Boiler-condenser with multiple exchanger cores in parallel or with multiple re-boiling or condensing streams

Definitions

  • the invention relates to a process and devices for the rectification of liquid mixtures boiling at low temperatures.
  • liquid mixtures are formed when gas mixtures are compressed, cooled, and condensed in order to be decomposed into their components.
  • the gas mixtures can be cooled to condensation temperature in various Ways. The necessary procedural steps are not explained here but are assumed to be known.
  • the condensation temperature is somewhat above the evaporation temperature because of the thermal resistance of the condenser-evaporator, but this difierence will here be disregarded.
  • a condenser-evaporator on whose condenser side nitrogen condenses and on whose evaporator side oxygen evaporates.
  • the heat of condensation of the nitrogen is thus transferred from the head of the lower column under higher pressure into the foot of the upper column under lower pressure for the evaporation of the oxygen boiling there.
  • the liquid high in oxygen collecting in the foot of the second column is partly evaporated in an evaporator-condenser which is located within the first column between head and foot, while the remainder of this liquid is expanded to the pressure of the last column, completely evaporated in the head of the second column, and then suppied to the third column between head and foot according to its composition.
  • This known three-column arrangement actually consititutes a double column which consists of two columns connected in series and with a third column connected in parallel.
  • the evaporator-condenser disposed between head and foot of the first column has an unfavorable eifect on the rectification in that column since it noticeably disturbs the equilibrium adjustment between liquid and vapor phase.
  • n any column except the serially last column and n+1 represents the serially next succeeding column thereto.
  • n any column except the serially last column and n+1 represents the serially next succeeding column thereto.
  • the number of columns is limited by the fact that in each preceding column an exactly defined higher pressure must prevail than in the following. In the limit case, however, the critical pressure may be selected as maximum pressure. Also it must be noted that for ideal mixtures-that is, in most cases in question for gas decomposition-the concentration differences between liquid and vapor phase at constant temperature decrease with increasing pressure. Generally, therefore, a greater reflux is required at higher pressure than at lower pressure.
  • the last stage or stages may, of course, be carried out under reduced pressure, that is, under vacuum, so as to be able to utilize fully the advantages of the rectification according to the invention.
  • n denotes a whole number from a-l to 1, both inclusive
  • the foot of the first column must be heated and the head of the last (ath) column must be cooled.
  • This may be achieved in known manner with a heat pump cycle.
  • the gas mixture cooled to condensation temperature may in known manner be liquefied in the foot of the first column, whereby heat is supplied there.
  • Enough reflux liquid is available for cooling the head of the last column when sufiicient amounts of liquefied heat product can be tapped from a sufficient number of columns. If the number of columns is large enough, a heat pump cycle may be dispensed with. This advantage is extremely important, because every heat pump cycle causes considerable losses of cold.
  • the gas flowing into the head of the nth column can be condensed there, whereupon a portion of the resulting condensate is returned into this column as reflux.
  • the lower boiling component A collects as pure primary product in the head of the nth column
  • the other portion of the condensate is expanded to the pressure of the ath (last) column and charged on the head thereof as reflux. It serves there at the same time for cooling.
  • the other portion of the condensate is expanded to the pressure of the (n+1)th column and is supplied to it between head and foot according to its composition, in order to be further decomposed there.
  • the procedure is, similarly as is already known for the double column, to condense a refrigerant in the foot of the first column, then expanding it and evaporating it in the head of the last column, whereupon in counter-current with itself it is warmed, compressed, subsequently cooled, and returned to the foot of the first column.
  • the refrigerant may flow in a closed cycle; it must be selected suitably as to its thermal properties.
  • the (lower boiling) decomposition product collecting in the head of the last column may be used as refrigerant.
  • the (higher boiling) decomposition product collecting in the foot of the first column may be advantageous to use as refrigerant the (higher boiling) decomposition product collecting in the foot of the first column.
  • the choice of refrigerant depends not only on its thermal properties, but also for example on 5% whether it can be compressed without trouble in dryrunning compressors, for it should not be contaminated by lubricants or moisture.
  • the gas flowing into the head of the nth column is tapped, condensed at least in part in the foot of the (n+1)th column, subsequently expanded to the pressure of the (n+l)th column and charged on the head thereof as reflux, while a portion of the gas flowing into the head of the last column is tapped, warmed in counter-current with itself, compressed, cooled again, finally condensed in the foot of the first column, then expanded and charged onto the head of this column.
  • This procedure is advantageous when the individual columns are arranged not in superposition but side by side and a liquid pump is to be avoided and when the lower boiling component A is obtained as pure primary product. For then no reflux can be obtained for this column in the head of the nth column.
  • the gas flowing into the head of the nth column can be condensed only in the foot of the (n+1)th column and be used in this column as reflux.
  • reflux is obtained from gas which flows into the head of the last column and which has been condensed after compression in the foot of the first column.
  • the liquid collecting in the foot of the nth column is tapped, expanded to the pressure of the (n+l)th column, evaporated in the head of the nth column, and subsequently supplied to the foot of the (n+l)th column, while a portion of the liquid evaporated in the head of the last column is warmed in counter-current with itself, compressed, again cooled, and finally supplied to the foot of the first column.
  • Th gaseous primary product still containing B that is, one consisting mainly of A, which flows into the head of the nth column, is expanded to the pressure of the (n+1)th column and supplied to it at a point corresponding to its composition, in order to be decomposed further. Heat is supplied to the foot of the first column by the compressed portion of the higher-boiling decomposition product B returned from the last column.
  • the rectification according to the invention is suitable in particular for liquid mixtures boiling close to the absolute zero point which contain a component to be recovered in very low concentration. Especially advantageous is the separation of mixture of hydrogen, deuterium hydride, and deuterium, in particular the two first named.
  • the new rectification process is, of course, suitable also for the decomposition of other, possibly multicomponent liquid mixtures.
  • An example is the mixture ethane-ethylene-acetylene, to mention onl one.
  • a device for the rectification, where the gas flowing into the head of the nth column is also condensed there, whereupon a portion of the resulting condensate is returned into these columns as reflux, is characterized in that at least three columns are arranged in superposition, and between the nth and the (n+l)th column a condenser-evaporator is located which belongs at the same time to the head of the nth and the foot of the (n+l)th column. If a closed refrigerant cycle is used with this arrangement, there must be in the foot of the first column a refrigerant condenser and in the head of the first column a refrigerant evaporator.
  • a device for the rectification according to which the lower-boiling gas A flowing into the head of the nth column is tapped as pure primary product and condensed in the foot of the (n+1)th column consists in its characteristic parts of at least three columns disposed side by side, a line for gaseous decomposition product leading from the head of the nth column to a condenser in the foot of the (n+1)th column, while from the lead of the last column a line leads to a compressor and thence to a condenser in the foot of the first column.
  • FIG. 1 is a diagrammatic representation of one form of apparatus, for use in carrying out the process of the invention, wherein three columns are superposed and wherein the crude gaseous mixture to be separated is passed through a heat-exchange coil in the sump of the serially first column before being introduced into said serially first column;
  • FIG. 1a is a diagrammatic fragmentary modification of FIG. 1, according to which the crude gaseous mixture to be separated is directly introduced into the serially firs-t column;
  • FIGS. 2, 3 and 4 show slight modifications of the apparatus of FIG. 1.
  • the columns according to FIGURES 1 and 2 are so operated that the lower boiling component A flows as pure primary product into the heads of the columns, while the higher boiling component B collects as impure primary product, that is, still containing A, in the feet of the columns.
  • component A serves as refrigerant for the heat pump cycle, in FIGURE 2, component B.
  • the columns according to FIGURES 3 and 4 are so operated that B collects as pure primary product in the column feet, while A contaminated with B flows as impure primary product into the column heads.
  • component A serves as refrigerant for the heat pump cycle, in FIGURE 3, component B.
  • the heat pump cycle may be omitted if the number of columns is made large enough.
  • Columns 1 to 6 may be equipped for example with sieve or hell bottoms or also with filling material.
  • the highest pressure prevails; in columns 2 and 5, a medium pressure; and in columns 3 and 6, the lowest.
  • the pressure ditferences existing between two columns are so adjusted, that is, the columns are so operated that the heat-transmitting primary product reaching the head of the preceding column, e.g. 1 or 4, condenses there at almost the same temperature as the primary product collecting in the foot of the following column, e.g. 2 or 5.
  • the heat of condensation of the respective head primary product is transmitted to the foot primary products in FIGURES 1 to 4 by means of the condenser-evaporator 11 and 12.
  • the counter-current heat exchanger 7, and the compressor 8 form parts of a heat pump cycle, in which a pure decomposition product, either A or B, serves as refrigerant.
  • the refrigerant is heated in counter current with itself, compressed in compressor 8, cooled again in 7, in order to be subsequently liquefied.
  • the gas mixture cooled to close to the condensation temperature enters column 1, or 4, in which highest pressure prevails, while the pure decomposition products leave the last column 3, or 6, in which lowest pressure prevails, at A and B.
  • the gas mixture A, B is supplied at so high a compression that it condenses in the condenser 19, in heat exchange with sump liquid contained in the foot of column 1, or 4, this sump liquid being evaporated at the same time.
  • the liquefied mixture A, B is then expanded in valve 21 to the pressure of column 1, or 4, and conveyed to it at a point between head and foot corresponding to its composition.
  • FIGURE la a modification is represented which can be employed in all arrangements shown in FIGURES 1 to 4.
  • the gas mixture A, B is there conveyed to column 1 directly, that is, unliquefied.
  • mixture A, B consists predominantly of the lower boiling component A. It is then advisable to proceed according to FIGURES 1 and 2.
  • the mixture A, B is conveyed to column 1 at a point between head and foot corresponding to its composition in liquid form (FIGURES 1 and 2) after expansion in valve 21 or in gaseous form (FIGURE 1a), whereupon it is decomposed into pure gas A and impure liquid B.
  • the pure A is liquefied in the condenser-evaporator 11 and returns in part to column 1 as reflux.
  • the remaining liquid A is tapped from column 1, expanded in valve 22 to the pressure of the (last) column 3, combined with a portion of the pure A liquefied in condenser-evaporator 12, and expanded in valve 23, and charged on the head of column 3 as reflux.
  • the pure decomposition product A flows otf through the line marked A.
  • the liquid collecting in the foot of column 1, still containing A but already enriched in B, is expanded in valve 24 to the pressure of column 2, and conveyed to it at a point corresponding to its composition, in order to be there decomposed further into .pure gaseous A and liquid still more enriched in B.
  • the liquid collecting in the foot of column 2 and strongly enriched in B is evaporated by means of the gaseous A condensing in the head of column 1 in the condenser-evaporator 11.
  • From the foot of column 2 liquid is continuously expanded over valve '25 to the pressure of column 3 and conveyed to it at a suitable point, in order there to be decomposed into pure A and B.
  • the pure product B leaves column 3, through the line marked B.
  • the amounts of material to be converted in the individual columns decrease from column to column.
  • pure A serves as refrigerant, which is tapped at 60 through valve 26, compressed in compressor '8, liquefied in condenser 20, and charged in valve 27 on the head of column 3, together with pure A from columns 1 and 2 as reflux.
  • pure B serves as refrigerant, which is tapped through valve 28 in liquid form from the foot of column 3.
  • a portion is branched off as product B through valve 26, and the other portion is compressed in compressor 8.
  • the refrigerant B is then liquefied in condenser 20, the liquid in the foot of column 1 being evaporated at the same time. After expansion in valve 27 it passes into evaporator 10, on whose exterior pure A condenses as reflux for column 3, and thence returns to 61.
  • the gas mixture to be decomposed consists predominantly of the higher boiling component B, it is advisable to proceed according to FIGURES 3 and 4.
  • the mixture A, B is conveyed to column 1 at a suitable point after expansion in valve 21 in liquid form (FIGURES 3 and 4), whereupon it is decomposed into impure gas A, which still contains B, and pure liquid B.
  • the impure A is liquefied in the condenser-evaporator 11 and in part passes back into column 1, as reflux.
  • the residual liquid impure A is expanded in valve 29 to the pressure of column 2 and conveyed to it at a suitable point. It is decomposed in column 2, into still impure, but more concentrated A, and pure liquid B.
  • the impure A condenses in condenser-evaporator 12; a portion is used as reflux in column 2, the remainder is sent through valve 30 into column 3, in order there to be decomposed into the pure end products A and B.
  • the pure liquid B which collects in the foot of column 1, is expanded in valve 31 to such a low pressure below that prevailing in column 3, that it evaporates in evaporator 10, at a temperature at which pure A in column 3 can condense on the exterior of evaporator 10.
  • the resulting liquid A serves as reflux in column 3.
  • the head of each column can be cooled to a temperature below the temperature of the foot.
  • pure A serves as refrigerant in a heat pump cycle consisting of counterflow device 7, compressor 8, condenser 20, and valve 34.
  • the refrigerant A is branched 011 at 62 through valve 26 from the decomposition product A.
  • the liquid B present in the foot of column 1, is evaporated by means of the heat of condensation released in condenser 20.
  • the liquid refrigerant expanded in valve 34 is charged directly on the head of the (last) column 3 as reflux.
  • pure B serves as refrigerant in the heat pump cycle.
  • This refrigerant is branched ofi at 63 through valve 26, and after warming up, compression, and again cooling in 51 and 52 it is conveyed to the foot of column 1, in gaseous form; It there liquefies giving off heat in exchange with the liquid running down in column 1 (reflux) and passes through valve 31 into evaporator 10.
  • Hydrogen contains 0.03% by volume of deuterium hydride. 90% of this deuterium hydride is to be separated and a mixture containing HD is to be obtained, from which deuterium hydride of desired purity can then be produced in a further rectification column known in itself.
  • the desired product containing 5% HD collects, which is obtained in gaseous form at B; it consists of 27 cu. m./ h. of a mixture containing 1.35 cu. m./h. HD. From this mixture containing 5% HD there are then obtained in a rectification column not shown 1.42 cu. m./h. of a mixture containing HD, which are to be regarded as crude product.
  • the heat flow resistance in the evaporator-condensers 11 and 12 causes a temperature diiference of less than 0.1 K. between the liquid condensing in the head of column 1, respectively 2, and the liquid evaporating in the foot of column 2, respectively 3. Sinceas has been mentioned-the amount of hydrogen to be conducted in the heat pump cycle is much lower in the three-column arrangement than with the use of a single column, more than 30% of energy can be economized.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
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  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Separation By Low-Temperature Treatments (AREA)
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258930A (en) * 1961-02-23 1966-07-05 Linde Eismasch Ag Process and apparatus for separating gaseous mixtures by low-temperature rectification
US3264830A (en) * 1963-08-09 1966-08-09 Air Reduction Separation of the elements of air
US3269131A (en) * 1956-10-18 1966-08-30 Linde Eismasch Ag Rectification of liquid mixtures boiling at low temperatures
US4414007A (en) * 1981-08-31 1983-11-08 United States Steel Corporation Process for separation of gas mixture

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3091094A (en) * 1957-07-04 1963-05-28 Linde Eismasch Ag Process of and apparatus for separating gases with cold production by workproducing expansion of low-boiling product
US3260058A (en) * 1962-05-09 1966-07-12 Air Prod & Chem Method and apparatus for separating gaseous mixtures, particularly helium-containing gases
IT1034544B (it) * 1975-03-26 1979-10-10 Siad Procedimento ed impianto per il frazionamento dell aria con colon na a semplice rettifica
US4415345A (en) * 1982-03-26 1983-11-15 Union Carbide Corporation Process to separate nitrogen from natural gas
FR2806755B1 (fr) * 2000-03-21 2002-09-27 Air Liquide Procede et installation de generation d'energie utilisant un appareil de separation d'air
DE10103968A1 (de) * 2001-01-30 2002-08-01 Linde Ag Drei-Säulen-System zur Tieftemperaturzerlegung von Luft

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1945367A (en) * 1931-06-13 1934-01-30 Air Liquide Process for the separation of gaseous mixtures
US2046284A (en) * 1933-05-18 1936-06-30 Union Carbide & Carbon Corp Apparatus for producing oxygen of high purity
US2146197A (en) * 1936-03-14 1939-02-07 Lee S Twomey Method of and apparatus for separating mixed gases and vapors
US2316056A (en) * 1939-08-26 1943-04-06 Baufre William Lane De Method and apparatus for rectifying fluid mixtures
US2645104A (en) * 1951-02-17 1953-07-14 Lummus Co Fractional distillation

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Publication number Priority date Publication date Assignee Title
US1664412A (en) * 1919-08-07 1928-04-03 Linde Air Prod Co Production of helium from natural gas
US2040116A (en) * 1935-06-11 1936-05-12 Air Reduction Method for the separation and recovery of krypton and xenon from gaseous mixtures containing them
US2213338A (en) * 1937-01-02 1940-09-03 Baufre William Lane De Method and apparatus for fractionating gaseous mixtures
BE502428A (de) * 1950-04-24
NL110792C (de) * 1956-10-18

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1945367A (en) * 1931-06-13 1934-01-30 Air Liquide Process for the separation of gaseous mixtures
US2046284A (en) * 1933-05-18 1936-06-30 Union Carbide & Carbon Corp Apparatus for producing oxygen of high purity
US2146197A (en) * 1936-03-14 1939-02-07 Lee S Twomey Method of and apparatus for separating mixed gases and vapors
US2316056A (en) * 1939-08-26 1943-04-06 Baufre William Lane De Method and apparatus for rectifying fluid mixtures
US2645104A (en) * 1951-02-17 1953-07-14 Lummus Co Fractional distillation

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3269131A (en) * 1956-10-18 1966-08-30 Linde Eismasch Ag Rectification of liquid mixtures boiling at low temperatures
US3258930A (en) * 1961-02-23 1966-07-05 Linde Eismasch Ag Process and apparatus for separating gaseous mixtures by low-temperature rectification
US3264830A (en) * 1963-08-09 1966-08-09 Air Reduction Separation of the elements of air
US4414007A (en) * 1981-08-31 1983-11-08 United States Steel Corporation Process for separation of gas mixture

Also Published As

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NL221114A (de)
GB856683A (en) 1960-12-21
BE560818A (de)
US3269131A (en) 1966-08-30
FR1184308A (fr) 1959-07-20
CH367525A (de) 1963-02-28
NL110792C (de)

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