US3003928A - Fractionating apparatus - Google Patents

Description

Oct. 10, 1961 R. R. PROCTOR ,0

FRACTIONATING APPARATUS Filed NOV. 13, 1956 2 Sheets-Sheet 1 RECORDING ELECTRONIC CONTROL AMPLIFIER CONT 'I5YOLLER STIIITI ON INTEGRATOR ""I I I C'ONTROL VA LVE REFLUX coogam our 7 c oourve con. c o0 1 ANT IN LE FRACTIONATION TOWER PREHgATER I I0 FEED 8 H REBOILER I a I L 9 FIG. I

PI5VEUMATIC CONTROL LER FLASH i EVAPORATOR 20 i I I 2: i 22 I CONTROLLER I I g'g INVENTOR.

27 TO STORAGE RONALD R. PROCTOR FIG. 2

ATTORNEY Oct. 10, 1961 Filed Nov. 13, 1956 R. R. PROCTO FRACTIONATING APPARATUS 2 Sheets-Sheet 2 ABSORPTION TOWER INLET 4o PNEUMATIC OPERATOR 3 REBOILER J 6 ga ner 4: kss I, 42

,ZCONTROLLER 52 og Te-cron i TU: r35 g; TO STRIPPER FIG. 5 v l i s4 59 L I v I r i 7 I ABSORPTION I i gowsn g 3 J 77 I 1 i l I 53 55 i 76 ns'rscron 4 72 i 62 I 75 L I EXTRACTION s3 TOWER 56 79 J 57 FIG. 4 71 INVENTOR.

RONALD R. PROCTOR 74 %M/W/ FIG. 5 I

ATTORNEY United States. Patent 0.

Ohio

Filed Nov. 13, 1956, Ser. No. 621,808 6 Claims. (Cl. 202-40) This invention relates to methods and apparatus for controlling processes involving separation of compounds and fractions differing from each other in physical and/ or chemical characteristics and is more particularly directed to methods and apparatus for fractionating hydrocarhens and for removing impurities from hydrocarbon compounds and mixtures.

In conventional-type operations, such as fractionation with heat and/or pressure to separate hydrocarbons of different boiling ranges; solvent extraction to separate hydrocarbons of difierent chemical structure, as, for example, separation of aromatics from paraffinic hydrocarbons; selective adsorption involving the use of an adsorptive material such as silica gel to separate aromatic from non-aromatic hydrocarbons and one aromatic hydrocarbon from another; and extraction of petroleum distillates for the removal of mercaptans from the distillate by means of aqueous and/or alcoholic alkali solution, it is desirable to control the operation to obtain maximum efficiency in removing the undesirable material or in separating the fractions from each other.

I have discovered that accurate control of processes of the type set forth above can be achieved by incorporating in the liquid material to be processed a small amount of a radioactive substance that has a physical characteristic sufficiently similar to one of the components or fractions to be separated that it will pass through the process with and be present in said fraction or component. The degree of separation eifected is a function of the particular characteristic common to both the component and the radioactive material. By placing a suitable radioactivity detector or counter in the stream of the component or fraction separated, or immediately adjacent to the line through which the component or fraction is withdrawn, a change in concentration of the radioactive substance will produce a change in the signal which the counter will transmit through a suitable amplifier system to operate valves placed in appropriate lines to modify conditions of operations in order to obtain optimum results. For example, in the case of fractional distillation, the radioactive substances may be a compound having a boiling point approximately the same as that of the component which it is desired to distill 01f, or which has a boiling point approximately the same as that of the lower or upper limit of a fraction which it is desired to remove. In the case of selective adsorption or absorption, the radioactive material may have a separation coemcient the same as, or close to, that of the component to be separated. In the case of extraction of an undesirable substance, such as mercaptan, the radioactive material may be one which has an extraction coefiicient approximating that of the mercaptan to be removed, or it may be the identical mercaptan containing radioactive carbon or sulfur.

It is an object of this invention to provide methods and apparatus for controlling operations involving the separation of liquid or gaseous mixtures into separate fractions.

It is another object of the invention to provide methods and apparatus for controlling operations involving the removal of an impurity from a liquid or gaseous mixture.

It is still another object of this invention to provide methods and apparatus for utilizing radioactive tracers in radioactive material used. use compounds containing radioactive iodine 131 because it emits gamma rays which are easily detectable and has a favorable half-life, namely, 8 days, which permits "ice the separation and purification of liquid and gaseous mixtures.

Still another object of the invention is to provide a simple and accurate method for controlling processes such as fractionation, selective adsorption and absorption, and purification of liquid and gaseous materials through the use of radioactive substances possessing a physical characteristic such that the efiiciency of such fractionation or purification is a function thereof and, therefore, it can be used to control the particular operation involved.

Other objects of the invention will become apparent from the following description and drawings, of which FIGURE 1 is a diagrammatic illustration of apparatus in accordance with my invention for carrying out conventional fractionation of hydrocarbons or other solutions; FIGURE 2 is a diagrammatic illustration of apparatus in accordance with my invention for separating natural gasoline from natural gas; FIGURE 3 is a diagrammatic illustration of apparatus in accordance with my invention for de-ethanizing natural gasoline by absorption; FIGURE 4 is a diagrammatic illustration of apparatus in accordance with my invention for separating hydroformate obtained by catalytic hydroforming of a narrow-cut, straight-run naphtha into a parafiinic and an aromatic fraction by adsorption; and FIGURE 5 is a diagrammatic illustration of apparatus in accordance with my invention for removing mercaptans from gasoline by extraction with a caustic soda-methanol solution.

In accordance with my invention, a compound containing radioactive iodine, phosphorus, sulfur, carbon, or other radioactive isotope, preferably a gamma ray emitter, is proportioned into the feed charged to the unit in which it is to be processed. A number of compounds containing radioactive carbon, sulfur, phosphorus and iodine are now available and others can be readily prepared. A list of such radioactive compounds can be found in the booklet Baker and Adamson Radiochemicals, published 1955 by General Chemical Division of Allied Chemical & Dye Corporation, 40 Rector Street, New York 6, New York. Among the radioactive chemicals listed are ethyl mercaptan containing sulfur 35, benzene containing carbon 14, iodopentane containing iodine 131, and methane containing carbon 14. In accordance with my invention, I prefer to use compoundsw-hich emit gamma rays since, as pointed out in the aforesaid pamphlet, alpha and beta rays are not as penetrating and therefor require the detector to be placed directly in the stream of material to be controlled. Since it is possible to detect as. low as one-millionth part or less of a radioactive material, it is necessary only to use low concentrations of the radioactive substance, as, for example, between .0001 and .00l% by weight of the total charge. It will be apparent that greater or lesser amounts may be used as a tracer and the amount will depend upon the specific activity and half-life of the particular Where possible, I prefer to suflicient time for storage before use and allows for rapid decontamination of the product stream in which it is present. 7

Where the. tracer is used to control a fractionation operation involving the use of -heat, a radioactive compoint substantially equal to the lower orupper limit of a desired fraction. It is preferable to choose radioactive materials which will not form azeotropes with any component of the feed stream. For example, where it 'is desired to fractionate a hydrocarbon mixture contain- .fractionating tower.

ing 0., through C paraflin hydrocarbons, so that C and lighter hydrocarbons are taken overhead, radioactive iodopentane can be used as the control material since it has a boiling point of 156 C., which is close to the boiling point of nonane, the highest boiling compound which it is desired to distill off. In an operation in which it is desired to separate methane from natural gas or gasoline, methane or ethane containing carbon 14 can be used as the control ingredient. In an operation where it is desired to de-ethanize natural gas, ethane containing carbon 14 can be used as the control material. In an operation involving the separation of aromatics from a hydrocarbon mixture containing aromatics, naphthenes and parafiins, benzene containing carbon 14 can be used as the control material. In an operation where it is desired to extract mercaptans from gasoline, ethyl or butyl mercaptan containing sulfur 35 can be used as the control material. When radioactive materials which emit gamma rays are used, detection may be by suitable means placed adjacent to the exterior of the pipe through which the controlled stream leaves the separator. However, when materials which emit only beta radiation, such as carbon 14 and sulfur 35, are used, suitable detection is attained by inserting the detector into the controlled stream or into a sample portion of the stream.

In order to more particularly point out the invention, reference is made to the drawings. In FIGURE 1 the numeral 1 indicates a line through which fresh feed, such as straight-run naphtha containing C through C paraffin hydrocarbons, is charged to preheater 2 where it is heated to the desired temperature for fractionation, namely, about 200 C. The preheated feed passes through line 4 into the lower portion of fractionation tower 5 where it separates into liquid and vapor fractions. The vapors pass upwardly through the tower and condensate passes downwardly. The temperature at the top of the tower is controlled by cooling coil 6 through which cooling liquid, such as water, is circulated. The temperature of the coil is maintained at a level to condense those hydrocarbons heavier than nonane. The vapor fraction containing the C to C hydrocarbons passes overhead through line 7 and is taken 01f as product through a suitable condenser and receiver. The residual material is withdrawn from the bottom of the tower 5 through line 8 and recycled through reboiler 9. Vapor is returned to the tower through line 10 and the C -C stream is withdrawn from the bottom of the tower through line 11. Detector 12, such as an Ohmart radiation cell, gamma scintillation detector or Geiger tube, is placed immediately adjacent to line 7, and is connected through a suitable electric circuit to amplifier-integrator 13, recording control station 14, and electric controller 15. Detector 12 is set so that when the intensity of the gamma rays emitted from the product passing through line 7 reaches a predetermined level, it will cause electronic controller 15 to operate electro-pneumatic valve positioner 16 which in turn will partially or completely open valve 17 to increase the flow of cooling liquid through coil 6. Likewise, as the intensity of the rays impinging on the detector decreases, it will cause the circuit to close valve 17 sufiiciently to cut down the amount of coolant liquid to the point required to raise the top temperature of the fractionating tower sufiiciently high to allow the C to C fraction to pass overhead. i

Radioactive iodopentane is proportioned into the feed material through line 18 in an amount sufficient to give an adequate radioactivity level in stream 7. It will be apparent that the control valve can be set to open and close to the proper degree in accordance with the intensity of the rays impinging on the detector by correlating the various intensity levels of radioactivity with stream analyses, or with temperatures at the top of the Any suitable instruments may be used in the circuit connecting the detector with the valve positioner. For example, the recording control station may be an American Electronic Recording Control Station Type 161, the electronic controller may be an American Electronic Controller Type 163, and the electropneumatic valve positioner may be an American Type 132C. Descriptions of these instruments can be found in Manning, Maxwell & Moore Catalogue 164.

Referring now to FIGURE 2, the numeral 20 indicates a flash evaporator to which liquefied natural gas under pressure is charged through line 21. Methane containing radioactive carbon 14 is proportioned into line 21 through line 22 in an amount suflicient to yield a radioactivity level of about 1000 counts per minute in stream 27. Pressure in flash evaporator 20 is controlled by valve 23 in vapor line 24. Valve 23 in turn is automatically controlled through pneumatic controller 25 operated by control means 26. The de-methanized liquid fraction is withdrawn from evaporator 20 through line 27 to storage. Radioactivity detector or counter 28 is placed in line 27 and is operatively connected through a suitable integrating and amplifying circuit to control means 26. If the methane content of the stream passing through line 27 exceeds a predetermined level, the radioactivity of the stream will increase, causing controller 26 to more completely open valve 23, thereby lowering the pressure in evaporator 20 and allowing more methane to flash oh and be removed overhead. Vice versa, if the radioactivity of the stream falls below the predetermined level, controller 26 will operate to close valve 23 until the operation is properly balanced. Referring to FIGURE 3, the number 30 indicates an absorption tower to which fresh feed as, for example, a stream of natural gas or gasoline, is fed through line 31. Absorption oil, which may be a fraction corresponding to kerosene or light gas oil, is fed to the upper part of the tower through line 32. The etiiuent or unabsorbed gas leaves the top of the tower through line 33 and the rich or fat absorption oil leaves the bottom of the tower through line 34. A portion of the rich oil is continuously withdrawn from the system through line 35 to a stripper (not shown). Another portion of the fat oil is continuously recycled through line 36 to reboiler 37 where it is heated and returned through line 38 to the bottom of the absorption tower 30. Heat is supplied to reboiler 37 by means of a heating fluid circulating through line 39 having inlet 40 and outlet 41. Valve 42 in outlet 41 is controlled by pneumatic operator 43 which in turn is actuated by controller 44 in response to signals received from radioactivity counter or detector 45 placed in line 35. A small amount of ethane containing C is added to line 31 through line 46. The control system for valve 42 is set so that if the intensity of the radioactivity transmitted, detected by detector 45, exceeds a certain level, valve 42 will be caused to open, permitting more heating fluid to pass into reboiler 37, thereby raising the temperature of the portion of the fat oil recycled back to the absorption tower. This will in turn decrease the amount of ethane retained by the oil. Likewise, if the radioactive signal received by detector 45 falls below the predetermined level, it will cause valve 42 to close, thereby reducing the heat input to the stream of fat oil recycled through 'line 38 back to the absorption tower, with the result that more ethane will be retained in the absorption oil and pass out of the system through line 35. Referring to FIGURE 4, the numeral 50 represents an adsorption tower containing a suitable adsorbent, such as silica gel. A feed stock, such as hydroformate, boiling within the range of approximately IOU-400 F., is charged through line 51 controlled by valve 52 into the top of adsorption tower 50. In passing through the adsorption tower, the aromatic hydrocarbons in the feed stock are preferentially adsorbed on the silica gel. The efliuent leaving the bottom of the tower through line 53 will be low in aromatic hydrocarbons and rich in paraffin and naphthenic hydrocarbons. During the adsorption cycle the paraffin-naphthene-rich stream is withdrawn through line 54 controlled by valve 55. During the desorption cycle the aromatic-rich effluent is withdrawn through line 56 controlled by valve 57. Desorbent liquid, such as water, methanol or acetone, is charged to the top of adsorption tower 50 through line 5-8 controlled by valve 59 during the desorption cycle. Benzene containing radioactive carbon 14 is proportioned into the feed stock through line 60. Valves 52, 55, 57 and 59 are operated by pneumatic operators 61, 62, 63 and 64, respectively, which are in turn controlled by controller 65 which in turn receives signals from radioactivity detector 66, preferably located in a slip stream of the efiluent, through a suitable integrating and amplifying circuit. Detector 66 is placed within outlet line 53, and controller 65 is adjusted so that when the radioactivity of the stream passing through line 53 reaches a predetermined intensity, it will close valves 52 and 55 and cause valves 59 and 57 to open. When the radioactive intensity of the stream 53 falls to a predetermined level during desorption, indicating that the aromatics have been sufiiciently desorbed from the silica gel or other adsorbent, the controller automatically closes valves 59 and 57 and opens valves 52 and 55.

In FIGURE 5, the numeral 70 represents an extraction tower for extracting mercap-tans from gasoline. Gasoline containing mercaptans is fed to the lower portion of the tower through line 71 and a caustic soda-methanol solution is fed to the upper portion of the tower through line 72. Treated gasoline is withdrawn from the top of the tower through line 73 and spent treating solution is withdrawn from the bottom of the tower through line 74. Line 72, through which the treating solution is charged to the tower, is controlled by valve 75 actuated by pneumatic operator 76 which is in turn actuated by controller 77. Controller 77 receives signals from radioactivity detector 73 through a suitable integrating and amplifying circuit. The radioactivity detectoris placed within treated product withdrawal line '73. A small amount of butyl mercaptan containing radioactive sulfur -35 is proportioned into line 71 through line 79. The

controller is set so that when the radioactivity of the stream passing through line 73 reaches a predetermined level of intensity, indicating that too much mercaptan is being left in the gasoline stream, valve 75 is caused to open to admit more treating solution tothe treating tower. Likewise, if the intensity drops below the predetermined level, indicating an excessive amount of treating solution going through the tower, valve 75 is caused to close.

The following specific examples will serve further to more particularly point out the invention:

Example I (refer to FIGURE 1) Naphtha, having the following composition:

is continuously charged at a rate of 579 barrels per hour and at a temperature of 335 F., to fractionation tower 5 maintained at a pressure of 15 lb./sq. inch, wherein it p is split into an overhead fraction containing nonane and lighter hydrocarbons, this overhead product being withdrawn through line 7, and a bottoms product containing 6 decane and heavier hydrocarbons. The bottoms product is withdrawn through line 11. Nonane concentration in the overhead product is maintained at about 19 mol percent, within the lower and upper limits of 17 and 20 mol percent, respectively. Tower pressure, feed composition, and feed quantity are maintained constant. Composition of the overhead product is dependent on the amount of coolant flowing through reflux cooling coil 6, this flow being regulated by control valve 17. Iodopentane containing radioactive iodine (I is continuously added through line 18 to the incoming feed stream as it enters tower 5 via line 4. The feed is first preheated in preheater 2. The radioactive iodopentane, which is added at a rate of 1.1 millicuries per barrel of feed, has boiling characteristics similar to those of nonane, and splits between the overhead and bottoms streams in about the same ratio as the nonane. Therefore, when the concentration of nonane in the distillate is at the desired level, of the radioactive iodopentane charged through line 18 passes overhead through line 7. A Geiger counter positioned adjacent to line 7 therefore registers counts per minute. When the nonane concentration in this stream drops below the desired level, namely, to the lower limit of 17 mol percent, the iodopentane content also decreases and the radioactivity level falls to 89 counts per minute. Conversely, when the nonane content rises to the maximum limit, radioactivity increases to counts per minute. The control point on recording control station 14 is therefore set at 100 counts per minute and the proportional band adjusted to cover the range of 90- 105 counts per minute. Thereafter, the fractionator is controlled by the automatic repositioning of flow control valve 17 for reflux cooling water.

is continuously charged to a flash evaporator at a. rate of 951 bbL/hr. and at a pressure of 225 1b./sq. inch. It is desired to produce a demethanized bottoms product having a methane content of 15% by volume, in which case the total bottoms stream has the following composition:

Vol., BbL/hr. Percent C. 16. 6 71 C0 27.0 123 (1 24. 8 113 1-04- 7. 0 32 11-01 10. 6 48 O 6. 1 28 05+ 5. 9 27 C1 8. 1 14 Total 100. 0 456 Since a change in the methane content of this bottoms product is directly proportional to any change in ethane content, it can be controlled by controlling the ethane content. This is done in the fol-lowing manner.

Ethane containing radioactive carbon 14, a beta emitter, isadded to the feed stream as it enters the tower in an amount of about 0.68-0.70 millicurie per barrel of feed. This radioactive material splits between the overhead and bottoms streams in the same ratio as the nonradioactive ethane in the feed. When the methane content of the bottoms stream is at the desired 15% volume level, 26.3% of the ethane in the feed passes overhead, and 73.7% remains in the bottoms. The radioactive ethane also splits in this manner, and a beta-radiation detector placed in the bottoms stream registers 100 counts per minute. This detector transfers impulses through integrating and amplifying instruments to a control instrument which is provided with proportional control. The control instrument in turn repositions the valve in the overhead line so that when the ethane content of the bottoms stream (and also the radioactivity) exceeds the desired level, the valve is opened to lower the pressure in the tower and permit more ethane to pass overhead. This also permits more methane to pass overhead so that the methane content of the bottoms product falls to the proper level. When the radioactivity of the bottoms falls below the control level, the control instrument closes the overhead control valve suiliciently to increase the tower pressure until the desired amount of ethane and methane are retained in the bottoms stream.

Since carbon 14, which emits only beta rays, is used, a radiation detector with a thin window is required, and is mounted within the flowing bottoms stream withdrawal line.

Example 111 (see FIGURE 3) Natural gas having the following composition is charged at a rate of 1,850 M s.c.f./hour to an absorption tower operated under a pressure of 250 p.s.i. at a temperature of approximately 100 F., counter-current to light gm oil at the rate of 850 barrels per hour:

The unabsorbed gas is withdrawn from the top of the tower at a rate of 1,300 M s.c.f./hour, and has the following composition:

Volume percent Methane 61.0

Ethane 28. 8 Propane 8 .8 Isobutane 0.7 Normal butane 0.7

Fat oil is withdrawn from the bottom of the tower at the rate of 1276 barrels per hour, and the material stripped from the absorption oil has the following composition:

B.p.h. Ethane Propane 185 Isobutane 36 Normal butane 109 Isopentane 31 Normal pentane 27 Hexane 22 Heptane and heavier 11 Ethane containing carbon 14 is continuously proportioned into the feed gas in an amount of 0.51 millicurie/ barrel-equivalent of fed. A radiation cell, placed within the withdrawal line for the rich absorption oil is connected through suitable amplification and controlling means, the controller being set so that when the number of counts per minute exceeds the valve is caused to open more and admit more heating fluid to the reboiler, as shown in FIGURE 3. When the number of counts falls below 100/minute, the valve in the heating fluid line to the reboiler moves toward closing to cut down the heat to the reboiler until the predetermined radioactivity intensity is restored.

Example 1V (see FIGURE 4) A liquid product boiling between 100 and 400 F., obtained by catalytic reforming of a straight-run naphtha, and having the following composition by volume:

Percent Aromatics 17 Naphthenes 26 Paraffins 57 with an API gravity of 74.4 and a sulfur content of 0.091% by weight, is charged at the rate of 500 barrels per hour to the top of a cylindrical adsorption tower 25 feet high by 10 feet in diameter, containing silica gel for the purpose of separating and purifying aromatics contained therein. Benzene, containing carbon 14, is proportioned into the charge in the amount of 0.5 millicurie per barrel of charge. A stream is withdrawn from the bottom of the tower during the adsorption period of the cycle, constituting 84.2% by volume of the feed. This stream, after separation from accompanying desorbent material, contains 1% of aromatics, 31% naphthenes, and 68% paratfins by volume, and has an API gravity of 58.1 and a sulfur content of 0.010% by weight. When the aromatic content of the effluent stream rises to 20%, determined as described below, feed entry is stopped and a flow of hot (350 F.) strippant, consisting of any paraffinic stock with a boiling range different from that of the feed, is admitted to the top of the tower to strip the adsorbed aromatics from the gel. Simultaneously, eflluent flow is switched from the paraflin-desorbent separation system to the aromatics-desorbent separation system. Benzene, toluene, and xylenes are readily separated from the aromatics-strippant eflluent by distillation, and the paraflinic strippant is recycled. When the aromatics concentration of the efiluent stream drops to 20 volume per cent, strippant flow is stopped, feed is again admitted, and etfluent flow is switched back to the paraifin-desorbent separation system.

The switching of flows during various parts of the cycle is automatically accomplished by adding benzene, containing carbon 14, to the entering feedstock. The benzene is adsorbed in a manner similar to the aromatics contained in the feedstock, and when the aromatics content of the eflluent stream rises to 20 volume percent, a radioactivity of 100 counts per minute is detected by a detector placed in a slip stream of the efiluent. This detected level is amplified and transmitted to a control instrument which repositions flow control valve to stop feed entry, start strippant entry, and transfer efiluent flow to the aromatics recovery section. During the stripping period, the aromatics content of the eflluent stream continues to rise, reaches a maximum, and begins to decrease. When the radioactivity falls to 100 counts per minute, the controller again repositions the flow control valves to .stop the stripping and resume feedstock admission and adsorption. 7

Example V (see FIGURE 5) Cracked gasoline having a boiling range of 100-420 F., a total sulfur content of 0.076% by weight, and a mercaptan sulfur content of 0.031% by Weight is treated in a continuous manner countercurrently with about 100% by volume of a solution consisting of 1 part of caustic soda and 0.4 part of methanol by weight. To the gasoline is continuously added 38.8 millicuries of butyl mercaptan containing radioactive sulfur 35. A sweet gasoline product is obtained containing 0.036% by Weight total sulfur and 0.0004% by weight of mercaptan sulfur. Control is effected by placing a radiation cell within the gasoline outlet line from the top of the treating tower and operatively connecting it through an amplifier-integrator, a recording control station, a controller, and a pneumatic valve positioner, as disclosed in connection with FIGURE 1, to a pneumatically-operated valve located in the fresh caustic-methanol solution inlet line. The controller is set to cause the valve to open wider when the radioactivity level detected exceeds 100 counts, per minute, thereby indicating that the mercaptan content of the gasoline is in excess of the predetermined maximum allowable, and is set to partially close the valve when the number of counts drops below 95 counts/ minute, indicating that the ratio of treating solution to gasoline is too high.

It will be seen, therefore, that by selecting a radioactive compound having a physical characteristic closely related to or the same as a component or fraction which it is desired to separate from a liquid or gaseous material, the operation can be easily and accurately controlled by determining the radioactivity of a stream to be separated from the system at optimum operating conditions and then adjusting the system so as to automatically maintain it at the desired level by the use of a radioactivity detector in conjunction with the necessary elements for integrating, amplifying, and recording, and operating one or more valves in the system.

Although the invention has been described in connection with the fractionation and purification of hydrocarbon mixtures, it is to be understood that it applies also to the fractionation and purification of othermixtures, such as, for example, oxygenated compounds from the Fischer-Tropsch synthesis or the separation of phenol from aromatic hydrocarbons, or the separation of other solvents used in extraction processes. It can likewise be used for such processes as dewaxing by incorporating radioactive carbon in wax in order to determine when the wax in the oil has been removed to the desired level. Other uses of the invention will occur to those skilled in the art.

I claim:

1. Apparatus for automatically and continuously effecting separation of a component of a fluid composition containing at least one other component comprising a separating chamber, a conduit for feeding fluid to said chamber, a conduit for withdrawing a fluid component from said chamber, a radioactive detector adjacent said withdrawal conduit, conduit means operatively connected to said chamber through which is adapted to flow fluid which aifects the operation of said separation, a valve in said conduit means, said valve being operatively connected to said detector so as to be motivated to opening or closing position in accordance with the radioactivity of the fluid passing through the conduit to which said detector is adjacent.

2. Apparatus in accordance with claim 1 in which the separating chamber is a fractionating tower, the detector is adjacent a vapor outlet conduit connected to the top of said tower and the detector controls a valve in a line connected to a reflux cooling coil located in the upper portion of said tower.

3. Apparatus in accordance with claim 1 in which said separating chamber is an evaporator, the detector is located adjacent a withdrawal line connected to the bottom of said evaporator and the valve is in a vapor withdrawal conduit connected to the top of said evaporator.

4. Apparatus in accordance with claim 1 in which the separating chamber is an absorption tower, the detector is adjacent a withdrawal line connected to the bottom of said tower and the valve is in a line circulating heating fluid to a reboiler connected to the bottom of said tower.

5. Apparatus in accordance with claim 1 in which the separating tower is an adsorption tower, the detector is adjacent a withdrawal line connected to the bottom of the tower, the withdrawal line branches into two parts beyond said detector, each branch is valve controlled and the valve in each line is operatively connected to said detector.

6. Apparatus in accordance with claim 1 in which the separating chamber is an extraction tower, the detector is adjacent a conduit connected to the top of the tower and the valve is in a feed line connected to the upper portion of said tower.

References Cited in the file of this patent Bradford: Radioisotopes in Industry, Reinhold Pub. Co., page 89.

Guest: Radiosotopes-Industrial Applications, Pitman Pub. Corp, copyright 1951, pages 94 and 95.

Claims (1)

1. APPARATUS FOR AUTOMATICALLY AND CONTINUOUSLY EFFECTING SEPARATION OF A COMPONENT OF A FLUID COMPOSITION CONTAINING AT LEAST ONE OTHER COMPONENT COMPRISING A SEPARATING CHAMBER, A CONDUIT FOR FEEDING FLUID TO SAID CHAMBER, A CONDUIT FOR WITHDRAWING A FLUID COMPONENT FROM SAID CHAMBER, A RADIOACTIVE DETECTOR ADJACENT SAID WITHDRAWAL CONDUIT, CONDUIT MEANS OPERATIVELY CONNECTED TO SAID CHAMBER THROUGH WHICH IS ADAPTED TO FLOW FLUID

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