USRE21265E - William h - Google Patents

Description

NOV. 14, 1939. w H, SHIFFLER ET AL Re. 21,265

PROCESS FOR PRODUCING ALUMINUM CHLORIDE Original Filed May 23, 1928 Reissued Nov. 14, 1939 UNITED STATES PATENT OFFICE PROCESS FOR PRODUCING ALUMINUM HLORIDE tion of Delaware Original No. 1,887,566, dated November 15, 1932, Serial No. 279,949, May 23, 1928. Application for reissue March 20, 1937, Serial No. 132,183

6 Claims.

This invention relates to the production of aluminum chloride or other metallic halide by heating carbonaceous material containing aluminum compounds or other metallic compounds in contact with chlorine gas and in the presence of oxygen.

For purposes of illustration, the process of our invention will be described as relating to the production of aluminum chloride, although it may be also used in the manufacture of other metallic halides. Aluminum chloride is generally manufactured by contacting a mechanical mixture of alumina and carbon at high temperatures with chlorine. Naturally occurring ores, such as bauxite, may be used as the source of alumina and powdered coal or coke or asphalt may supply the carbon for the reaction.

A method and apparatus for producing metallic chlorides from finely divided mixtures of carbonaceous material and metallic compounds has been invented by John Kuhl and William H. Shiffier and is disclosed in a copending application for patent. The present invention relates to a similar process but is primarily directed to the treatment of coked mixtures of alumina and carbon in comparatively large lumps and discloses a means for producing aluminum chloride (or other metallic halide) more efficiently and economically than other methods and devices in current use. The efficiency and economy of the process is due largely to continuous operation and to the fact that dilute chlorine gases, such as are produced from the Well known Deacon process which provides a concentration generally too low for eflicient chlorination, may be employed.

An object of this invention is to disclose a continuous process for the production of aluminum chloride from an alumina-containing coke.

Another object of the invention is to disclose a continuous process of chlorinating alumina-carbon mixtures with dilute chlorine gases in the presence of heat,

Another object is to provide a process of treating coke in the form of granules or lumps in counter-current flow to heated gases comprising mixtures of air and chlorine to produce aluminum chloride in suitable form for use as a treating agent for mineral oils.

A still further object of this invention is to provide a method of chlorinating alumina-carbon mixtures in an eiiicient and economical manner.

Other objects, results and advantages of our process will become apparent from the following detailed description thereof. For illustrative purposes, one preferred form of apparatus for carrying out this invention is also shown and the advantages resulting from the particular character and arrangement of elements and the apparatus will also become apparent from the subsequent description.

The appended drawing referred to hereinafter E illustrates one form of apparatus diagrammatically, the invention not lying in specific details of construction, but in the general arrangement and combination of elements, the details of con- L struction being within the skill of the engineering and mechanical arts.

The raw material upon which the process or method of this invention may be carried out, may

be any coke or carbonaceous material containing ing what is termed a "coke containing alumina,

which is a macroscopically homogeneous intimate mixture of carbon and alumina.

It has been discovered that any alumina-coke of the above described character may be efiiciently and economically chlorinated and treated for the recovery of valuable products by passing the coke through a retort counter-current to the flow of highly heated gases containing chlorine.

For example, the coke containing alumina may f be charged into the top of a vertical retort and a bed of coke made within the retort while highly heated gases (such as air or air and producer gas) containing chlorine are introduced at the bottom of the retort so that aluminum chloride is produced during the passage of the gases through the mass.

Aluminum chloride thus produced is in the form of vapor, and as such is carried from the top of the retort to suitable recovery means, while the spent coke or ash is withdrawn from the bottom either intermittently or continuously The vaporized aluminum chloride together with other gases of the reaction may be scrubbed with oil to condense and absorb the aluminum chloride in the form of a suspension or tar which is suitable for use as a treating agent for mineral oil. The use of oil in condensing and absorbing aluminum chloride is particularly efiicacious in the treatment of the dilute product resulting from the process of this invention.

The method provides for the contact of partially reacted and preheated mixture of carbon and alumina (coke containing alumina) with chlorine and air at relatively high temperatures of the latter, thereby allowing the chlorinating reaction to take place progressively and insures a substantially complete conversion of all alumina present in the coke into aluminum chloride.

A novel means of continuously maintaining the required temperature of reaction is also provided, so that none of the carbon in the alumina coke will be utilized in generating the heat, if this saving of carbon in said coke is desired.

The invention hereinbefore described may be more fully understood by reference to the attached drawing which, as has been stated before, illustrates one form of apparatus which may be used in carrying out the broad aspects of our invention.

In the drawing, I represents a vertical, internally heated retort of suitable height and size and lined interiorly with a suitable refractory material. The retort I is provided with a feeding device 2 for introducing alumina coke of any desired description into the retort.

The feeding device 2 may be provided with double doors 3 and 4 so that coke may be charged into the retort intermittently or it may be fed continuously by a suitable continuous feeder during the reaction taking place within the retort I, without the escape of vapors therefrom through such coke feeding means.

Highly heated gases are introduced into the lower portion of the retort I and they may be heated by means of a separate carbon monoxide gas producer 5 which is charged with a suitable coke such as a fuel coke of low volatile matter content through a feeding device 6 which may also be provided with double doors I and B. The gas producer may also be provided with double clean out doors such as the doors or valved outlets 9 and III, thereby allowing the removal of ashes intermittently or continuously without the escape of vapors. The gas producer 5 is further provided with an inlet II near the bottom of said producer 5 for chlorine gas and air which are discharged from the producer through an outlet I2, leading into the lower portion of the vertical retort I.

The highly heated gases containing chlorine pass through the bed of the coke containing alumina within the retort I and a reaction takes place, resulting in the formation of aluminum chloride in the form of a vapor. Spent coke and ashes resulting from this reaction may be discharged from the vertical retort I through double outlet or discharge means I3 and I4.

It will be seen that the coke present in the upper portion of the retort I is preheated by the gases and vapors generated in the lower portion of the retort and the highly heated gases introduced into the retort I through the inlet l2 first come in contact with the preheated and partially reacted coke. It will be understood that any other means of heating gases such as air and chlorine may be used and the invention is not to be limited to the generation of heat by a combustion of the coke in a separate gas producer. As a matter of fact, some air may be introduced together with the chlorine and carbon monoxide and other gases into the retort I and the portion of heat of reaction derived from a partial combustion of coke within the retort I.

The desirability of generating heat by partial combustion of coke within the retort I depends somewhat upon the character of the coke being fed to the retort and the proportional quantity of carbon in the coke. For example, if the alumina coke does not contain a large excess of carbon, then it may be desirable to preheat the gases entering the retort in a gas producer as shown.

The aluminum chloride, together with other gases, leaves the retort I through a vapor outlet I5 in the upper portion of the retort I and these mixed gases are then conducted to a downtake pipe IS in which they are brought in contact with a spray of cooling and absorbing oil admitted into the upper portion of the downtake pipe I6 by line I1. This cooling oil serves to condense and wash down a portion of the aluminum chloride present in the gases discharged from the retort I through pipe means I5 and such oil, together with absorbed or condensed aluminum chloride, is discharged into an oil and tar settling chamber I8. By tar is meant a thick rather viscous suspension which is formed by the absorption of aluminum chloride in an oil.

Gases or components not condensed or absorbed by cooling oil in the down-take pipe I6 then pass from the upper portion of the settling chamber I8 upwardly through a scrubbing tower 1 I9 which may be a packed tower as shown in which a large surface area of contact between the gases and a cooling or absorbing medium is provided. The cooling or absorbing medium may be introduced into the upper portion of the tower I9 through line 20 and discharged into the tower by any suitable spray nozzles or the like. Gases or components not absorbed or condensed within the tower I9 then pass out of the system by line 2| to storage or other treating apparatus, as desired, condensed and absorbed products being carried downward into settling chamber I8. Since large volumes of gases containing but a small quantity of aluminum chloride are discharged by the retort, condensation of aluminum chloride on cooled surfaces is impractical since heat transfer is ineffective but absorption of aluminum chloride by means of oils as stated hereinabove is very effective since it produces essentially perfect contact between the gases and the absorbing oil, the gases may be passed in large volume and at high velocity, and this method obviates the use of an intervening solid wall through which heat transfer must take place.

The lower portion of the settling chamber In is provided with an outlet pipe 22 which leads to a pump 23 so that oil containing aluminum chloride may be withdrawn from the lower portion of the settling chamber I8 either intermittently or continuously as desired to storage or for use as a treating agent for mineral oils by various well known aluminum chloride processes, by line 24.

Cooling oil may be introduced into the system by means of line 25 provided with a valve 26. Valves 2'! and 28 are provided so as to regulate the amount of cooling oil being introduced into the down-take pipe I5 and scrubbing tower I9,

respectively. Cooling oil containing substantially 3| may then be returned by line 32 to line H and to the down-take pipe and scrubbing tower.

Excess oil accumulating in the system may be removed therefrom by discharging the oil from the upper portion of the settling chamber l8 by means of line 29 and pump 30 into an outlet line 33, valve 35 being closed and valve 35 in line 33 being open.

The advantages of the above described method and apparatus wll be evident to those skilled in the art. Although a method and apparatus have been described with particular reference to an embodiment shown in the drawing, it is to be understood that invention is not limited thereto, but numerous changes and modifications may be made within the scope of the following claims.

We claim:

1. The method of chlorinating coke containing alumina to produce aluminum chloride, comprising: carbonizing a mixture of alumina and a fluid pitchy substance whereby a macroscopically homogeneous coke comprising an intimate mixture of carbon and alumina is formed; forming a bed of such coke containing alumina in a vertical retort; maintaining the said bed in the retort by introducing such coke into the upper portion of the retort and discharging ash and spent coke from the bottom portion of the retort; continuously introducing into the bottom of the retort a dilute chlorine gas mixture including air, the proportion of air in the mixture being suflicient to maintain a reaction temperature within said bed but containing a ratio of oxygen to nitrogen no higher than that which exists in air; continuously discharging gases and vaporized products of reaction from the upper portion of the retort; and continuously removing condensible products including aluminum chloride from the discharged gases by contact with oil.

2. The method of chlcrinating coke contain ing alumina comprising, forming a macroscopically homogeneous coke containing alumina by mixing alumina and a pitchy substance and carboniaing the mixture, forming and maintaining a bed of said coke in a vertical retort, introducing said coke containing alumina into the upper portion of said retort, forming a mixture of gases containing chlorine by continuously passing air and chlorine through a separate bed of coke, heating said gases to a reaction temperature by combustion of coke in said separate bed, introducing the heated dilute chlorine gas mixture including air into the lower portion of the vertical retort, said heated gas mixture containing oxygen in no higher proportion than that which exists in air, passing the heated gases upwardly through the bed of coke containing alumina in said retort, and discharging gases and vaporized products of reaction from said retort.

3. A method of chlorinating coke containing alumina to produce aluminum chloride, com prising carbonizing a mixture of alumina and a fluid pitchy substance whereby a macroscopically homogeneous coke comprising an intimate mixture of carbon and alumina is formed; forming a bed of such macroscopically homogeneous coke containing alumina in a vertical retort introducing such coke containing alumina into the top of said retort, discharging spent coke and ash from the bottom of said retort, passing a dilute mixture of chlorine and air through a separate retort containing coke, heating the dilute chlorine gas mixture by combustion of coke within said separate retort, discharging heated gases containing chlorine and air from said separate retort into the lower portion of the vertical retort, the proportion of air in the mixture being suiiicicnt to maintain a reaction temperature within said bed but containing a ratio of oxygen to nitrogen no higher than that which exists in air, passing the heated gases upwardly through the bed of coke containing alumina in said retort, and discharging gases and vaporized products ol reaction from said retort.

i. A method of chlorinating coke containing alunilina comprising, forming a bed of macroscopically homogeneous coke containing alumina derived by carbonizing a mixture of alumina and asphalt in a vertical retort, introducing such colic containing alumina into the top of said retort, discharging spent coke from the bottom or said retort, passing a dilute chlorine gas mixture including air into the lower portion of the vertical retort and upwardly through the bed of coke containing alumina in said retort, said gas mixture passed into the retort containing oxygen in no higher proportion than that which exists in air and discharging gases and vaporized products of reaction from said retort, and continuously condensing aluminum chloride from the dilute gases discharged from the retort by contact with oil.

5. A method of chlorinating coke containing alumina to produce aluminum chloride comprising, iorming a bed of macroscopically homogeneous coke containing alumina derived by carbonizing a mixture of alumina and asphalt in a vertical retort, intioduoing such coke containing alumina into the top oi said retort, discharging spent coke from the bottom of said retort, passing a dilute chlorine gas mixture including air into the lower portion of the vertical retort and upwardly through the bed of coke containng alumina in said retort, said gas mixture passed into the retort containing oxygen in no higher proportion than that which exists in air, discharging gases and vaporized products of reaction from said retort, and continuously condensing condensible products from the dilute gases discharged from said retort by contact with oil.

6. A method of chlorinating coke containing alumina to produce aluminum chloride, comprising introducing a macroscopically homogeneous coke derived by carbonizing a mixture of alumina and asphalt and comprising an in timate mixture of carbon and alumina into a reaction chamber, maintaining a bed of said coke in said reaction chamber, continuously introducing into the bottom of the chamber dilute chlorine gas mixture including air, the proportion of air in the mixture being sufiicient to maintain reaction temperature in said reaction chamber but containing oxygen in no higher proportion than that which exists in air, passing said gases through the bed of coke in said chamber, continuously discharging gases and vaporized products of reaction from the upper portion of said chamber, discharging ash and spent coke from the bottom portion of said chamber, and continuously removing condensible aluminum chloride from the gases and vaporized products of reaction by contact with oil.

WILLIAM H. SHIFFLER. WARD P. ANDERSON.

CERTIFICATE OF CORRECTION.

Iovember 11 1959 WILLIAM H. SHIFFLER, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 27, claim 11, after the word "from" insert the upper portion of; and that the said Letters Patent should be read with this correction Reissue To. 21 ,265.

therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 50th day of January, A. D. 19b0- Henry Van Arsdaie,

(Seal) Acting Commissioner of Patents.

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