US1999437A - Method of coking heavy fluent hydrocarbons - Google Patents

Description

April 30, 1935. c. w. ANDREWS ET Al. 1,999,437

' METHOD oF COKING HEAVY FLUENT HYDRocARBoNs Filed June 24, 1932 2 Sheets-Sheet l April 30, 1935.

c. w. ANDREWS ET AL METHOD OF COKING HEAVY FLUENT HYDROCARBONS 2 Sheets-Sheet 2 Filed June 24, 1952 @w r r mn e BE NQ NE@ @ai @y @1m www r ,QFSD mi@ wnmiwf ngi EN A @ESOWUG SED. @5.5% .H SO Q L, l NWO E@ s www wwwa om mw lm/ |11 l/v a d\u E DLD. CR mm E38@ L ,V N y WU@ @bl @I MOH bll. @Q 8H dus@ E SG i- Il U/ ,h B LWQCQNUVQ I x: @n Eff :msm WE@ Patented Apr. 3o, 1935 METHOD COKING HEAVY FLUENT HYDROCARBONS Charles W. Andrews, Chicago, Ill., and Roy S.

Petersen, San Antonio, Tex., assignors to Brassert-Tidewater Development Corporation, Chicago, Ill., a corporation of Delaware l f Application June 24, 1932, serial No. 619,086

2 Claims.

This invention relates to a new and improved method of treating hydrocarbons. More specifically the invention relates to the coking of the non-volatile residues of petroleum hydrocarbons.

5 The invention'further involves the cracking of volatile portions of the hydrocarbons.

It is an object of the present invention to provide a new and improved method for the treatment of hydrocarbons and more particularly to the coking of petroleum hydrocarbons and the cracking oi volatile constituents. oi' the material being treated.

It is also an object to provide a method capable of being carried out at substantially atmospheric pressures. l

It is an additional object to provide a method in which the solid residue may be recovered as a hard, dense coke of low volatile content;

It is a further object to provide a method whereby heat from intermediate stages of the process may be utilized for the purpose of topping the charging stock.

A further object is to separately preheat the charging stock and the recycle bottoms from the bubble tower whereby temperatures most suitable for the cracking of the two stocks may be maintained and thereafter discharging the streams into the coking ovens.

It is also an object of thev invention, where under certain vapor phase. conditions the carbon formed may notl have suflicient liquid to form salable coke in the oven, to use the incoming charging stock either directly or through the cleaning tower to supply the necessary amount of liquid to properly bind the carbon particles into coke during the coking operation.

It is a further object to assist in coking charging stock by means of heat carried into the oven bythe recycled condensate.

Other and further objects will appear as the description proceeds.

The assistance in coking charging stocks by means of the heat carried into the oven by the recycled condensate, is of great importance as many charging stocks will be found which cannot be satisfactorily preheated to a high enough temperature to permit of rapid coking and cracking in the oven. Byour method we not only have the heat supplied through the floor of the oven,

but also an additional supply of heat in the recycled condensate which has been heated to a temperature of at least .900 F. to 1000" F. and preferably higher, for heating, cracking vand coking the incoming charging stock. It will be understood that if the recycled condensate is at liquid phase temperatures further Acracking and coking will go on in the oven; if, however, it is heated to substantially vapor phase temperatures whereby gas, cracked vapors and carbon are formed, only a portion of the carbon will remain 5 in the oven on account of the velocity of the gases carrying it forward into the cleaning tower.

It is thereforefa part of this invention to remove this carbon from the vapors as far as feasible and return it to the coking chamber. We 10 `do this by either using bottom condensate or charging stock as cleaning media, these streams being returned to the oven. Where charging stock is used as the cleaning medium it will be partiallyA reduced in the operation. In forming 15 coke under these conditions much, if not all of the carbon from the bottom condensate will become a part of the coke formed from the charging stock. The quality of the coke formed in the oven will, to a large extent be governed by the 20 amount of heavy hydrocarbons in the return to the coke ovens from the cleaning tower.

-We have shown somewhat diagrammatically certain preferred embodiments of apparatus adapted for carrying out our invention in the ac- 25 companying drawings, in Which- Figure 1 is a 'diagrammatic layout of apparatus, shown in elevation and partly in section, and flow sheet showing one preferred form;

Figure 2 is a fragmentary elevationshowing a 30,

" connection with the coke oven charging and overhead otake.

Referring first to the form shown in Figure 1, the apparatus includes the pipe still I I, coke ovens I2, cleaning tower I3, bubble tower Il and gas 40 separator I5. The charging stock line I6 is provided with the branch II controlled by valve I8, this branch leading to the coke oven. The Y.line I6 is also provided with the branch I9 controlled by valve 20 leading to an intermediate portion of the cleaning tower I3. The vapor line 22 leads from the top of the oven I2 to a lower point in the cleaning tower I3. The line 23 leads from the top of the cleaning tower" I3 to 50 an intermediate portion .of the bubble tower Il, this line -carrying the vapors from the cleaning tower to the bubble tower.

The line 24 leads through condenser 25 to an intermediate portion of the gas: separator I5. 55,

T'e line 23 for. carrying gas from the gas separator is provided-with the branch 21 which may lead to any suitable gas holding or using ap- 'paratus (not shownl.. The line 23 is also provided with the branch 23 which, in turn, is provided-with branches 23 and 33 leading to the heating `ues o! the coke oven, and with the branch 3| leading to the combustion chamber of the pipe still II.

Gasoline from the gas separator I 3 may be drawn of! through line 32 by pump 33. This line 32 communicates with the gasoline draw-oi! line 34 controlled by valve 33. The line 32 also is connected to the gasoline redux line 33 controlled by valve 31. This line 33 leads into an upper portion of the bubble tower I4.

A distillate take-oil line 33 controlled by valve l33 leads of! from an intermediate portion 'of the bubble tower I4. 'I'he bottom distillates from the bubble tower I4 are drawn of! through line 43 by pump 4|. This line 43 communicates through valve 42 with the pipe still feed line 43. It also communicates through valve 44 with the reflux line 43. This line 43 has a branch 43 controlled by valve 41 leading into the top of the cleaning tower I3. It also has a secondbranch 43 controlled by valve 43 leading into a lower portion of the cleaning tower I3. The line 33 leads from the lower portion of the cleaning tower I3, being adapted to draw oii the heavy distillate. This linel 33 includes the pump 5I and leads through valve 32 into the top of the coke oven I2. The bottom oi' the cleaning tower I3 is shown as provided with a lock 33 through which any heavy sludge or settlings in the bottom may be periodically removed, and the pump 3| is so placed as to handle the heavy sludge aswell as the heavy distillate through line 33.4

'I'he pipe still feed line 43 connects to the radilant and convection sections 34 and 33 ofthe pipe still. The pipe 33 leads from the end of the pipe still coils tothe coke oven, being controlled by valve 31. The cleaning tower I3 and bubble tower I4 have been shown as containing bailles or trays to assist in contact between the gases and liquids. 'I'he details of construction of these elef ments of the apparatus form no part of the present invention and any types of cleaning, refluxing and tractionating equipment may be used without departing from ourinvention.

In Figure 2 a modiiied form of connection to the pipe still 33 has been shown. The gas oil or condensate is handled through the gas o il line which connects to the radiant section 32 and a convection section 33. These sections may be connected in the form of construction shown in Figure l in a manner similar to sections 34 and 33 of pipe still II. In addition a second convection section 34 is provided for use in heating the charging stockwhere that stock does not come from prior treatment apparatus at a temperature adequate for the present treatment. This convection section 34 could be connected in charging stock line I 3 oi.' the form shown in Figure l.

The form of construction shown in Figure 3 includes the pipe still or heater 1I, coke oven 12, cleaning tower 13, condenser 14, gas separator 13 and gas oil accumulating drum 13. The chargingstockv line 11 is provided with the branch 13 controlled by valve 13, this branch leading to the lower section of the cleaning tower 13. This line 11 is also provided with the branch 33 controlled by valve 3| leading into the top of the coke oven 12.

The towerl 13 is provided with the gas oil orv -of the gas separator 13.

condensate draw-oi! passage 3| which leads into the top of the gas oil accumulating drum 13. This passage 3| is made of such size as to serve both as a draw-oil for the condensate and to permit vapors from the drum 13 to return to the tower 13.

The draw-oi! line 32 at the bottom of drum 13 is provided with the pump 33 and with the line 34 which leads to the junction 33. The junction 33 is connected inA one direction to the pipe still coil 33. The other end or this coil 33 is connected to the line 31 which leads into the top oi'- .the coxe oven 12 through valve 33. The lower end of the pipe still coil 33 is also connected through line 33 and valve 33. to the bottom of the tower 13. 'I'he'draw-o 3| at thebottom ot tower 13 is provided with pump 32 adapted to force the material through line 33 and past valve 34 into the topof the'coke oven 12. f

The Junction 33 on line 34 has a second connection to the line 33, which discharges through valve 33 into the passage 31 leading from stand.

`the plate 33 to denefthe passage area for the overhead products from the coke oven.

'I'he line |33 carries the overhead products from tower 13 through condenser 14 tol an intermediate portion of the gas separator 13. 'Ihe gases leave the gas separator through pipe I 34 and they pass through branch- |33 controlled by valve |33 to the burners in thecombustion passages in the coke oventhrough lines |31 and |33. "Ihe line |33 leads to the burner in the combustion space of the pipe still 1I.

'A water drain ||3 is provided at the bottom The gasoline line leads from the side of the gas separator 13, this line being provided with the pump I I2. The dis 'charge side of the pump |I2 leads through line I|3 to any suitable gasoline holding or using apparatus (not shown). The line |I4 controlled by valve II 3 is adapted to carry reux gasoline to the top of the cleaning tower 13.

Referring now-to the form of construction shown in Figure 4, the coke oven |23 has a charging and cleaning chamber |2I connected to'the top of the oven by passage |22. The charging stock line |23 enters the upper portion of the chamber I 2|. 'I'his chamber |2I is provided with the bubble trays or equivalent contact means 24. The line |25 controlled by valve |23 leads into the lower portion o1' the chamber I2I, this line being adapted to introduce the highly heated condensate from further stages in the process.

The'vapor line |21 leads from the top oi' the chamber |2I and is adapted to carry the overhead products to any desired i'ractionating or other apparatus (not shown) for further treatment of the products.

The form of construction shown in Figure 4 may be substituted in the form shown in Figcontact chamber I2I may be substituted for the lower section of the cleaning tower 13.

In the operation of the apparatus as shown in Figure l to carry out our improved method of treatment charging stocks which usually are either gas oils, bottoms from oil topping operations or residues from oil cracking may be at suilicient temperatures as the result of previous operations to make preheating unnecessary. If not already at a suillcient temperature,- preheating is desirable to a point usually in excess of 800 F. -This preheating can be carried on either in a separate preheater or, as shown in Figure 2, in the convection section of a regular pipe still in which the radiant sections are being used to heat the recycle condensates from the bubble tower. The heating of the recycle stock may however be carried on in any suitable type of still separate from the charging stock heater. This step is an important element in our invention as it is lwell known that residues cannot be heated to as high a temperature as recycle condensates such as gas oils which are returned from the bubble tower. In a preferred method of operation we carry the temperature of the charging stock vbetween 800 F. and 900 F. whereas the temperature of the recycled condensate would normally be at least approximately 900 F. and would preferably be from 1000 F. to 1100 F. or even higher if necessary to secure the desired amount of vapor phase cracking.

We prefer to use the charging stock in the cleaning tower for the rst cleaning, although it may be discharged directly to the ovens through valve I8, if desired. 'Ihe vapors passingoff the coke ovens through line 22 carry with them entrained coke particles and tar globules or polymers which it is very desirable to remove before reaching the bubble tower. Where the charging stock does this satisfactorily, no further cleaning is necessary; otherwise gas oil from the bottom of the bubble tower passing through valve 41 will be used to further clean the vapors and remove as far as possible any objectionable matter.

'I'he redux to the top of the cleaning tower I3 through valve 4l also has the function of regulating the temperatures of the gases and vapors passing over to the fractionating or bubble tower I4. If the charging stock through line I9 and valve 20 functions, it will assist in cleaning the ascending vapors.

Different charging stocks will require different temperatures at the top of the cleaning tower and it is our purpose to maintain these at as high a temperature as is desirable, usually above 600 F., by maintaining the temperatures in the column. In some cases the charging stock will be at suflicient temperature to actually increase the temperature of the above vapors while in other cases it may be necessary to bring the vapors from the ovens at a higher temperature for the same purpose. We have provided inlets for gas oil through valve 49 should lower temperatures be required or it not be desirableto use charging stock in the cleaning tower.

The vapors pass over through line 23 to bubble tower Il. 'I'his tower may be of any conventional form and has for its purpose the production of suitable end point gasoline as an overhead and of gas oil suitable for further high temperature cracking or other disposition as a bottom condensate. We have shown a distillate side takeoi 38 which has for its usual purpose the balancing of the operations so that no undue amount of distillate will build up `in the condensate returning to the pipe still as -the distillate usually requires a diierent temperature for cracking from that of the vregular bottom condensates. Obviously distillate may be removed for other uses if so desired.

It is a feature of this invention to increase the temperatures in the coke ovens by preheating the condensate bottoms passing through line 43 in the pipe still II to as high temperatures as may be carried under good operating conditions. In some cases temperatures may be high enough to vaporize practically all the oil passing through the still rather than heating the oil in the liquid phase. Valve 51 would be used to control these operations as well as cutting off the oven from the supply.

Preferably the oven inlet through valve 51 connected with the pipe still is at the opposite end from the vapor outlet so that full advantage may be taken of the volume of the oven for the completion of the cracking reaction. The return from the cleaning tower through valve 52 and the direct Jcharge through line I1 and valve I8 are also located at the same end as the connection through valve 51.

In operating the form of apparatus installation shown in Figure 3, part or all of the hot condensate is returned to the bottomof the cleaning tower. 'Ihis tower may be a combination cleaning and bubble tower as shown in the drawings, this being accomplished by a dividing plate which enables the drawing oif of the condensate of a desired specification, at the same time allowing the heavier tars and coke particles to fall to the bottom where they may be removed by the pump, and forced back into the oven for further treatment. In this case the charging stock is also used as a cleaning medium for the lower section of the tower, with an auxiliary supply of condensate from the gas oil accumulator drum should it be needed for better fractionation, or the condensate may be used in place of charging stock as a cleaning medium.

We haveindicated a standpipe in which a spray of condensate or charging stock is used to cool the vapors coming from the ovens and at the same time check the objectionable deposits in the line. The line |30 controlled by valve I3I connects the charging stock line I8 with the line 95 leading into the standpipe 98. By use of this line the charging stock may be mixed with condensate through line in going into the standpipe or the charging stock may also be used through the line I30 and discharge into the standpipe.

At the lower end of the standpipe is a diaphragm and an adjustable oil seal below it.` The level of the oil seal may be raised or lowered by the valve IIJI being opened or closed or maintained in an intermediate position automatically if desired. In this way suction on the oven may be regulated to whatever extent desired.

The hot return distillate preferably is injected tangentially below the level of the oil in the bottom of the cleaning tower 13 in order to keep the body of liquid in constant motion and thus prevent building up of carbon deposits. It will be understood that any free carbon present is sufiiciently low in quantity so that the body remains liquid under the conditions of the method and that the liquid and any entrained carbon are discharged from the cleaning tower 'I3 in a liquid condition.

- Figure 4 shows another method of accomplishing these results. In this case the cleaning tower is placed immediately on top of the oven, the

charging stock being used as a cleaning fluid.

Trays or bubble caps may be used to obtain the by the hotvapors. 'I'he hot condensate ,which is not vaporized will Viiow down into the oven for further treatment together with the charging stock. f

It will be noted that the forms of apparatus shown in Figures l and 3 are actually quite similar in operation and results obtained although they are somewhat different inA appearance. In

f each there are separating and fractionating zones which-are directly connected. In Figure 1 these zones are represented by cleaning tower I3 and bubble tower I4, while in Figure 3 they are represented by the portions below and above the draw oif deck above which the passage 8| is connected, This passage 8l is. in general, the substantial equivalent of line 40 of Figure v1.

The ovens may be supplied in' batteries of any desired number and charging of each oven in the battery continues until a desired depth of coke is' formed in the oven. Feeding is then discontinued on this oven, the coke allowed to dry and then pushed out in the usual way, after which the oven is closed and the cycle starts again.

While we have shown a single pipe still, oven, cleaning tower and bubble tower, it will be understood that with Aa battery of ovens the other elements may be provided in any desired number. One still may serve a plurality of ovens and likewise each oven may have separate cleaning and fractionating apparatus or several ovens or the whole battery may be served by a single set of apparatus for handling the overhead products. The apparatus is shown diagrammatically in the drawings and it will be understood that it may be changed to meet varying conditions and requirements. We therefore contemplate such changes and modications of lboth method and apparatus as come within the spirit and scope of the appended claims.

We claim:

1. The method of coking heavy fluent hydrocarbons which comprises introducing heavy liquid temperature, such as 900 F., than that of the heavy hydrocarbons, whereby heat from the condensate supplies heat to the mixed bottoms in the fractionating means and separates suiilcient form a charging stock largely free from lighter fractions at a temperature above 600 F. and at a concentration of coking constituents sufciently low to effect the discharge of bottoms in a liquid condition, discharging the bottoms into a coking chamber, and heating externally the cokingA chamber to add substantially all the further heat necessary for coking, and producing a hard, dense coke.

2. The method of coking heavy fluent hydrocarbons which comprises introducing heavy liquid hydrocarbons into a separating and fractionating zone, admitting to the separating and fractionating zone an intermediate hydrocarbon condensate into contact with the heavy liquid hydrocarbons, thecondensate being derived from the products of the fractionating zone, heating said condensate before return to the separating and fractionating zone to a materially higher' temperature, such as 900 F., than that of the heavy hydrocarbons, whereby heat from the condensate supplies heat to the mixed bottoms in the separating and fractionating zone and separates suiiicient lighter fractions from the heavy hydrocarbons to form a charging stock largely free from lighter fractions at a temperature above 600 F. and at a concentration of coking constituents suiciently low to effect the discharge of bottoms in a liquid condition, discharging the bottoms into a coking member, heating lighter fractions from the heavy hydrocarbons to externally the coking chamber to add substantially all the further heat necessary for coking, and producing a hard, dense coke, and returning condensate from the overhead from the coking chamber to the initial separating and fractionating zone. f

CHARLES WL ANDREWS. ROY S. PETERSEN.

CERTIFICATE oF CORRECTION.

Patent No. 1,999, 437. April so, 193s.

CHARLES w. ANDREWS, ET AL.

lt is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, second column, line 42, claim 2, for "member' read chamber; and that the said Letters P atent should be read wi th this correction therein that the same may Conform to the record of the case in the Patent Office.

Signed and sealed this- ZSthdaj of June, A. D. 1935.

Bryan M. Battey (Seal) Acting Commissioner of Patents.

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