US2398818A - Apparatus for separating gases and the like - Google Patents

Description

April 23, 1946. N. c. TURNER 3, APPARATUS FOR SEPARATING GASES AND THE LIKE Original Filed Novw15, 1940' able heating means therefor.

heating and cooling.

Patented Apr. 23, 1946- Nelson Turner, Tulsa, Okla.

Original application. November 13, 1940, Serial No.

' 1941, Serial No. 401,583

7 Claims. (CL 183-45) This invention relates to apparatus for sepa rating gases, vapors or liquids,- particularly light hydrocarbon gases or vapors such as ordinarily occur in natural gas, the apparatus hereinafter described being particularly intended for laboratory analysis, although it may also be utilized for industrial gas fractionation. The present application is a division of an application Serial No. 365,415, filed November 13, 1940.

In accordance with the method invention de-.

Divided and this application July 9,

3, the heat being applied locally be inning at the large end of the column.

Mercury from a movable reservoir 6 is introduced part-way into the heated zone of the column, to bring it to the boiling point, and its vapors are employed to clean the adsorbent charcoal of the adsorbed gases. As the adsorbent in the lower zones is freed of gases, the heater and scribed in said co-pending application, the use of liquid air or other low temperature cooling medium is dispensed with. Said method invention employs a substance capable of adsorbing the gases which are to be separated and means for driving the pure gas fractions from said adsorbing material in the sequence in which they are released by fractional distillation.

The present invention provides apparatus for obtaining sharper separation between the individual components of the gas than was possible heretofore. It also provides a much more rapid mercury reservoir 6 are raised to a fresh portion of the packing to successively drive off the gases in succeeding zones. The heater 5 and the mercury container '6 are movable simultaneously.

The mercury container 6 is connected by a flexible conduit 6 to the bottom of the fractionat ng column I. Valved connections .6 and 6' of Fig. 3 are provided, one for admission of samples and the other for the purpose of flushing-out the sampling lines.

As shown'in the drawing, the fractionating columnis generally mounted vertically with its larger end at the bottom. It may, however, be

analysis which in some instances may be completed in about one-fifth of the time required by the low temperature fractionating method.

The invention will become more apparent from a consideration of the accompanying drawing in which like reference characters designate like parts and in which:

Fig. 1 isa diagrammatic view of apparatus for separating gases embodying the principles of this invention;

Fig. 2 a side elevational view partially in section of a fractionation column; and

Fig. 3 a view diagrammatically illustrating a portion of the fractionating column and adjust- With reference to Figs. 1'to 3 inclusive of the drawings, the numeral l designates a as fracticnating column having progressively reducing cross-sectional areas forming chambers of such proportionthat the internal cross-sectional area at the outlet end 2 is only a small percentage of the internal cross-sectional area of chamber 3 at the inlet or entrance end of the column. The column may be provided with fins 4 'for rapid The fractionating column I is filled with an adsorbing material such as activated cocoanut shell charcoal Ia, Fig. 3, and a heating means such as an electrical heater 5 is provided to drive the gases out of the adsorbent material. Heater 5 is movable vertically of the column, it being shown in the extreme bottom position in Fig. 1, and moved slightly upward in the position of Fig.

placed ina reclining position or oriented in any other way for special uses in adapting the column to unusual problems.

A by-pass tube 1, Fig. 1, may be connected into the column at some point along its length to indicate during sampling the progress of the heavier constituents of the mixture being adsorbed. The by-pass tube is provided with avalve 8 so that the gases may be forced to leave the column through the small outlet end 2, controlled by valve 9, from which the gases pass to the separator I [0 of a condenser l3. The separator is provided with an inlet II to refill the column with hydrogen. or other gas during preparation for sampling. A liquid collector I2 is provided beneath the separator II] to collect and measure any condensate which may form in the separator or in the condenser. The fractionated gases enter the condenser l3 from separator l0 and by a capillary tube l4 pass to a junction l5 which is connected to the low pressure side of an adjustable manometer l6, Fig. 1, and from which the gas flows to avolumeter ll through a thermal conductivity cell l8 and a temperature equalizing coil 20.

The high pressure side of manometer I6 is connected to separating chamber In by tubing [9; butthere is no gas flow through l9 because of the liquid seal in the manometer. 'The'gases pass through the thermal conductivity cell l8, then through atemperature equalizing coil 20,

which is connected to the top of the volumeter H. The thermal conductivity cell i8, coil 20 and the volumeter ll may be immersed in a constant temperature bath contained in a tank 2|;

shown in Fig. 1; or gases may be withdrawn from outlet 22, Fig. 1.

The operation of the above-described gas fractionating apparatus and method is briefly as follows.

Column 1 is charged with the activated charcoal I or other adsorbing medium, and the gas to be sampled is conducted to the bottom of the column through the connection 6 The gases are adsorbed by the charcoal I and when the column I is filled, as indicated by a change in thermal conductivity of efliuent gas, the valve oi? the connection 6 is shut-ofi.

The bypass valve 8 may be opened during sampling to indicate the progress of the heavier constituents of the mixture being adsorbed. The sample is drawn on through the by-pass I until a slight change in the composition of the eiiluent gas indicates that the heavier components of the mixture have penetrated the packing to the point at which the by-pass begins. The sampling is then discontinued and distillation of the sample is commenced, with the by-pass valve 8 closed and valve 9 open.

Mercury reservoir 6 is then raised enough to introduce mercury into the entrance end 3 of the column, and heater is energized and the gas fractions are driven from the adsorbing charcoal material of the heated portion of the column into the upper sections of the column.

As the body of the adsorbed components is driven up through the adsorbent the tendency of the heavier components to remain behind is sufll-- ciently pronounced to cause the individual com ponents to separate into layers, each layer consisting of substantially pure component. As the various components are driven through the adsorbent bed by the action of the heater, the stratum between any two adjacent components,

which contains substantial quantities of bothcomponents, finally reaches a limited minimum thickness dependent upon the relative adsorption characteristics of the two components. In order that the volume of mixed gases in this stratum may be reduced to a negligible value in comparison to the volume of pure components above and below it, the cross-section of the adsorbent bed at the outlet end of the column is substantially less than the cross-section at the charging end. Since the thickness of the stratum of mixed components is independent of the diam-. eter of the cross-sectional area of the adsorbent bed, the volume of adsorbed components in this stratum will decrease in direct proportion to the cross-sectional area, resulting in an extremely sharp separation of the individual components as they are delivered from thetop of the column.

The separated gases pass out of the column through the condenser l3 and separator, and flow through the capillary tube It, past connection block l5 0! the manometer l8, and to the 2,898,818 a gas outlet 22 extends from the volumeter, as

The volumeter measures the total volume 01' gas passing out of the column during the time between consecutive changes in comp'osition. From a record of the volumes of the various fractions as measured and the temperature and barometric pressures, the volume percentage of the various components may be calculated. The outlet connection 22- provides for the collection of isolated fractions in their purified state. I

.After completion of distillation of a sample, the column is prepared for the next run by lowering the mercury reservoir and heater to their initial positions at the bottom of the column. While the mercur is being lowered, somegas such as air or hydrogen is allowed to enter the column through the connection II, The use of hydrogen rather than air is helpful in the analysis of natural gases and other similar samples since it is readily displaced and permits the sampling to proceed at a greater rate. In cases where these gases might interfere with the analysis of the sample, the column may be sealed during the lowering of the mercury reservoir andthe sample admitted to the evacuated column. An especially constructed column in which the mercury reservoir could be lowered approximately one meter below the sample inlet connection would be necessary for use of this vacuum technique.

By means of the reduction in area of the column the bulk of the adsorption of gases is made to occur near the entrance end and a long chamber is provided substantially free of thej heavier components of gas mixture for refractionation and further purification of the iractions as they approach the outlet end. The mercury entering the bottom of the column not only drives the adsorbed gases out 01 the adsorbent but also seals the adsorbent material during distillation so that readsorption of gases from another portion of the column cannot take place during the distillation.

Means other than the electric heater may be employed for driving the gases out, of the ad- I sorbent oi the adsorbed gases. As the adsorbent in this zone is freed of gas, the heater and mercury level are raised to a fresh portion of the packing. The reading obtained is a function of the viscosity and of the density or specific gravity of the gas. When these properties of difierent ases are difierent, a series of characteristic manometer readin s are obtained which are Deculiar to those gases. The device may be calibrated by passing various pure gases through the system and noting the manometer readings obtained.

The unique.construction of the column consisting of consecutive chambers of reduced areas either continuously or in steps, as shown in the drawing, results in the bulk of adsorption of gases occurring near the entrance or enlarged end of the long chamber which is maintained substantially free of the heavier components of the gas mixture for refractionation and further purification of the fractions as they approach the outlet end.

It will be evident to those skilled in the art that the principle of adsorption and expulsion of gases by a fractionating column, as herein disor physical properties of the gases and the instant application is primarily directed to the use of the fractionating column rather than novel features of the control and measuring apparatus,

which is the subject matter of additional applications.

I claim:

1. A fractionating column for separating gases or vapors comprising an elongated chamber, shaped to provide contiguous sectional chambers of reducing cross-sebtional areas from one end to the other, said column being open at its large end and having connections at its smaller end l for gas analysis apparatus and a solid adsorbent material filling said column.

2. A fractionating column for separating gases or vapors comprising an elongated chamber of gradually reducing cross-sectional area open at its large end and having connection at its small end for communication with gas analysis apparatus, said column being filled with a solid gas adsorption material, and heating. means enveloping said column and being adapted to progressively heat the adsorbent material from the large to the smallend of the column.

3. A fractionating column for separating gases or vapors comprising an elongated chamber of reducing cross-sectional area open at its large end and having connection at its small end for communication with gas analysis apparatus, said column being filled with a solid gas adsorption material, heating means enveloping said column movable from the large to the small end of the a column and being adapted. to progressively heat the adsorbent material from the large to the small end of the column, and means for replacing the gases expelled from the adsorbent material with mercury.

4. A fractionating column for separating gases or vapors comprising an elongated chamber of reducing cross-sectional area open at its large end and having connection at its small end for communication with gas analysis apparatus, said column being filled witha solid gas adsorption material, heating means enveloping said column and being adapted to progressively heat the adsorbent material from the large to the small end of the column, and means for replacing the gases expelled from the adsorbent material with mercury, said heating and mercury feeding means being movable-from the large to the small end of the column.

5. A fractionating column for separating gases or vapors comprising a container forming an elongated chamber of gradually reducing cross-sectional area open at its large end and having connection at its small end for communication with gas analysis apparatus, said container having fins on the external wall thereof constituting maximum heat adsorption and radiation areas, the said chamber being filled with gas adsorption material, and meansapplicable through the external wall of said container for applying heat to any selected area of said elongated chamber.

6 A fractionating column shaped to form contiguous communicating spaces of gradually reducing cross-sectional area from one end to the other and filled with an adsorbent material, means for charging the gas at the large end of .the column and for withdrawing gases at the reduced end of the column, the relative diameters and length of the contiguous sections of the column being of such proportion as to separate the components of the gases into stratum or fractions, and means for heating the several sections. of the column successively from the large end to the reduced end of the column to release the sap-- arated'stratum of the gases in a predetermined.

' sequence.

'7.' A fractionating column shaped to form contiguous communicatingspaces of gradually reducing cross-sectional area from one end to the other and filled with an adsorbent material, means i being of such proportion as to separate the components of the gases into stratum or fractions, a heater disposed around the column movable from end to end and means for charging the column with mercury as the gases are expelled from the] adsorbent material, said heater and mercury charging means being movable relative to the column and to each other coacting in relation to expulsion of the gases to heat and seal the adsorbent material.

NELSON C. TURNER.

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