US2609332A

US2609332A - Hydrocarbon conversion

Info

Publication number: US2609332A
Application number: US46167A
Authority: US
Inventors: Vernon O Bowles; August H Schutte
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1948-08-25
Filing date: 1948-08-25
Publication date: 1952-09-02
Anticipated expiration: 1969-09-02

Description

P 1952 v. o. BOWLES ET AL 2,609,332

HYDROCARBON CONVERSION Filed Aug. 25, 1948 E'levator Calciner ATT Y the: reaction zone. I

Patented Sept. 2, 1952 ration of- Delaware A;pplicat;ion.August 25,1948;SerialNo;46,-167 l "JIhis invention relates. toranlimprovedlniethod of. producingcoke-andis more particularly a con- ;tinuation-in-part vof our "application Serial ,No.

Idond-Lin". favor. or -app1icatiorl!.'Serial No; .3174? BClMms. (cocoa-14) fi1e'd'January'22, "1948, now Patent Nofasersse.

In accordance with ourprior invention, we have 'disclosedl-a newmethod of lproducingl'oke'.byithe 7 continuous conversion .'of {lh.eav'y hydrocarbons such as residues'iwhi'ch arethebypro'ducts of ,crude' oil'dist'illatiomor,tars which are vbio-Prodrappliedjto'andcarried by: the coke particles during the continuous movement of the column downwardly, and when these conditionsiare' met there is no adherence between particles ofisufficient extentto interfere with 'thei'free flowing -character of the' column. j p

"Our invention has also utilized the technique of avoiding the} addition :Of heatjto thecoking operation except inthe introduction of the? preheated oilcharge and thecokepa'rtifcles so that maximum temperature is at the'topof the'reactionzone-and so that there Will -be no tendency of 'the vapors' to condense asthey move upwardly andflareremoved. There is also no dilutionirom products of a combustion as -air is excluded from fliInxour Vprior applications it was "contemplated that the reheating would :be accomplishedtby introducing air into a sealed'reheating zone with a partial combustion of'some of the coke andthe substantially complete vfreeing-of the volatiles contained therein. While it was found that such operation resulted in a highly dense and superior form.of coke, it has. now u beenfound that .more efi'ective andamore economical control can-be accomplished when onlythe removed netproduct is so'calcined. T V p v .The present invention hasfor its principal "object,tthe productionof high quality calcined coke'of dense nature containing substantially no asha'nd' having a low' volatile" content.

A further object of the invention is to'provide an improved method of calcining coke in a con- 'tinuous contact coking unit whereby substantial heat economiesare obtained by the handling of "dry coke-at elevated'temperatures.

. "$32 Y a i. Itlisan I additional. object r th ,inve'ntionffto proi'r'iide' improved .apparatusfi for controllingnlthe size of the column'particles and more'efficie'ntly reheating said particles in a l continuous Lcontact ieo in umt, o i 1 E L Fiirther objects and advantages .ofjour' invenlt io'n will appear from the following description of Ta"preferre'd"form of, embodiment thereotut'akenlin connection .with'fthe attached-"drawing which" is al 'rdiagr'ammatic elevational' view of the. essential parts are contin ous contact coking. unitfor'the production of calcined coke. I a p In accordance with apreferrd form .oftembodimentfo'f our invention,"the reactor generally indijcated "at H! is a suitable sealed vessel through jwhichcoke is continuously fed through the inlet 12! and is passed downwardly solely by'igravity over thedistributing b'aifie I 4,1'adjacent' which'jthe liquid hydrocarbon charge introduced a't 1'6 is'disr ted by. the'distributo'r'"elements rs, T'The e11 "preferably heated tea-suitable 1 minimum temiperature, as inheater' I'5, whichai'dsin its partial ivaporizationl in contact with the companions. "Ihesecolumnar"flowing particles are maintained at atmo'derate temperature to accomplish a vaporization or; a desired" portion of the, char-gel and the r man-on "ofai'dry jcoke coating jjon'i th ticl'e's" as ftheymovedownwardly tothe outle f'Thisoutlevmayf'have asteam seal-lineill'; v

jj ItfiSOll'r experiencethatiairee flowingfgravity 'paclgedi'mass can" successfully 'car'r'yj and co vent to dry cokeand '"vapors' up "to j about 5 its iv-eight of hydrocarbons "of '"jthe fresidualjgt .pe, *wherethediscrete cokepa'rticles vary in 'sizefro'm -As th'e contact particles move-through thereactor' 1 9; uniform flow' isnecessary-which may Joe accomplishedby 'fiow "c'o'ntrol plates2Z "of any well known type. 'Uni'form' flow assureyeven- :ness' of charge distribution and uni'formresidence time, it being known that the viscosity of the charge at the elevated temperature is about one tenth that of water. As the coating or particle growth thus is of the order of only 0.001 inch per pass, it will be apparent that repeated passage through the reactor is contemplated. This is accomplished by discharging the coatedparticles through outlet control valve 23 into elevator inlet 24, and. with any coke make-up from line 24a, into a suitable elevator 25 which carries the particles to the elevator outlet 26.

In accordance with our invention, we prefer to pass all of the contact particles into a classifier generally indicated at 28 which may be of' any suitable type and which will discharge a uniform quantity of coke of desired size through line 34 for return to the system. Fines may be removed at 30 and the larger size particles removed as net product through line 32. If found desirable, some of this net product from line 32 may be passed through a crusher 33 and returned to the coke make-up line 24a for recycling. t

Although the reaction is both exothermicand endothermic and nearly balanced in reactor in 'where the conversion is to dry coke, there is some heat loss by radiation and otherwise, and the particles which are to be returnedto the reactor 4 the reheater 35 to the stack 43. It is of course understood that appropriate waste heat recovery means may also be used to aid in the cooling of the products of combustion.

In accordance with our present disclosure, we have efiectively segregated the reheating and reaction zones and provided for the passage of the contact particle material through the elevator 25 While said material is in its coolest condition. The reduction in temperature at this point decreases the elevator operation cost. Furthermore only the net coke removed through the line 60 is calcined, with some economy in H] are conveniently passed through the reheater 35. This is a separate sealed chamber connected with the classifier 28 through the inlet line 34. The upper partof the reheater 35 is provided with a series of radiant heat burners, generally indicated at 38, which are supplied by manifolds 40 with fuel gas from line 4| and air from line '42; The continuously changing surface layer formed by the cokeparticles as they enter the reheater 35 is thus continuously brought up to .the desired temperature. Products of combustion flowdownwardly and are discharged to. stack line 43 from vapor collecting channel 44. The reheated coke particles then pass through seal pipe 45, having steam purge line 46, to the inlet 12 to the reactor ID, as previously mentioned. We have found that the continuous, and repeated-passage of coke particles through the reheater and the reactor tends to create a highly dense, non-porous coke which appears to, be radically different from the ordinary porous coal coke or petroleum coke known to the industry. Tofurther improve the qualities of the coke productwe find it desirable to pass it.,;through the calciner 48 and subject it to controlled. calcining with air introduced at 49.-- This novel product, which possesses great utility as a heat exchange medium and for metallurgical purposes, is described more fully and claimed in our copending application, Serial No. 46,168 filed August 25, .1948.

,Thehcoke normally leaving the classifier 28 through the outlet 32 is already in ahighly heated condition, the temperature of which may range from 900. to 1,000 E, is substantially all of a size, and is, of course, completely free of any liquid. In the calciner 48 it is possible to rapidly bring the coke particles up to.-a temperature of, 2,000 F. and the products of the combustion may be carried through the line 50 to the, upper partof the reheater 35. r r

In view of the fact that the products of combustion leave the calciner 48 at approximately 2,000 F. they can be effectively used for reheat- .ing of the bed particles before they enter the reactor H]. In addition, the combustion gases .are substantially cooled in their passage through operation, thereby avoiding the need of high temperature operations in connection with all of the coke.

A typical unit for converting 18 A. P. 1. Mid Continent reduced crude at the rate of 4500 bbl. per day, and producing major yields of dry coke will circulate from 200 to 300 tons per hour of contact material and the reactor may be approximately 16' in diameter with a 28' bed andthe reheater may be approximately 16' in diameter and have a 14' column, With equilibrium coke the solids feed is from 9 to 15 times the oil feed by weight.

v Inasmuch as calcining is largely for the purpose of removing volatile material, and only high temperatures are required, this may be accomplished either by combustion or by radiation from a suitable heatfsource It is to be understood that either type may be used as conditions require. It isof course also possibleto remove partially calcined coke directly from the system if the extra treatment is not required,v

While we have shown and described a preferred form of embodiment of our ,invention we are aware that modifications maybe rnadethe'reto andwe therefore desire a broad interpretation of our invention within the scope and spirit ofv the carbons in liquid phase, converting the spreadcharge into solid dry coke adhering to the coke particles of said bed and vaporous lighter hydrocarbons, removingfsaid vaporous hydrocarbons from said reaction space, recycling a'substantially uniform quantity of said coke particles having solid dry adhered coke to a reheating space sealed off from said reaction space, continuously removing a net coke product corresponding in amount to the cokeproduced in the reaction space, calcining said net product coke in the presence of an oxygen containing gas, introducing ,theprodnets of combustionfrom the calcining step into the reheating space to reheat th recycled. coke particles therein, exposing the. coke particles as they are'fed into thereheating space to the heating effect of radiant heat burners, collecting and removing the products of combustion from the reheating space, and passing the reheated coke flow of products of combustion from the reheating space to the reaction space.

In a continuous contact method of converting heavy hydrocarbon oils into coke and lighter hydrocarbons which comprises continuously and repeatedly passing a column of gravity packed preheated coke particles through a sealed reaction space solely by gravity, introducing a heavy hydrocarbon oil charge largely in liquid phase into the upper part of said coke column while so controlling the rate of movement of the column, the rate of feed of the charge per unit of column volume, the temperature of the entering coke particles and the distance through which the column moves before leaving the reaction space that the adhering liquid carried by the column particles will be converted to lighter hydrocarbon vapors and a dry, non-adherent coke coating on the particles, removing said lighter hydrocarbon vapors from the reaction space, discharging said coke coated particles from the reaction space, reheating and returning a substantially uniform quantity of coke particles to the reaction space, continuously removing a net coke product substantially equivalent to the amount produced by the conversion, subjecting the net coke product thus removed to a calcining operation in the presence of a gas, whereby the net coke product is raised to a substantially higher temperature than that in the reaction space, and cooling the gas from the calcining operation by contact with the said coke particles returning to the reaction space.

3. The method as claimed in claim 2, including the steps of classifying the dry coke coated particles discharged from the reaction space and removing the larger size particles as the net coke product supplied to the calcining operation.

4. The method as claimed in claim 3, including the step of bypassing a part of the removed larger size particles through a crushing operation to the reheating operation.

5. In a closed system for the continuous conversion of heavy residual oils into coke and lighter hydrocarbons by application of said oils to a gravity packed downwardly moving column of preheated coke particles, the combination comprising an upright reactor vessel having a particle inlet at its upper end and a particle outlet at its lower end, means for feeding heavy residual oil into the upper portion of the reactor vessel, means for withdrawing lighter hydrocarbons from the reactor vessel adjacent the oil feeding position, means for controlling the passage of coke particle through said particle outlet, an upright particle reheater chamber, said reheater chamber having a particle outlet at its lower end connected directly with the particle inlet of the reactor vessel, particle transfer. conduit means extending between the particle outlet of the reactor vessel and the inlet of the particle reheater chamber, a product particle drawoif line in said transfer conduit means, a coke particle calciner bustion thus supplied.

6. In a closed system for the continuous conversion of heavy residual oils into coke and lighter hydrocarbons byapplication of said oils to a downwardly moving column of preheated coke particles, the combination comprising a vertical reactor Vessel having an inlet at its upper end and an outlet at its lower end, means for feeding heavy residual oil into the upper portion of the reactor vessel, means for withdrawing lighter hydrocarbons from the reaction vessel adjacent the feeding position, valve means for controlling the passage of coke particles through said outlet, a vertical reheater chamber, said reheater chamher having an outlet at its lower end connected with the inlet of the reactor vessel, a particle classifier receiving all the coke particles discharged from the reactor vessel, said classifier being positioned above said reheater chamber and adapted to separate the coke particles passing from the reactor vessel into several sizes, a first line for feeding particles of a desired size from the classi fier into the upper end of the reheater chamber, a second line for discharging particles of another size from the classifier for removal a product, a coke particle crusher, a valved line connected to the second line and including said crusher for recycling any desired portion of said particles of another size from the classifier to a point between the outlet of the reactor vessel and the inlet to the reheater chamber, whereby the particles thus recycled may be reduced to a suitable size for re-introduction to the system, a coke particle calciner of the combustion type connected in said second line beyond said valved line, and. a third line for leading the hot gas produced in the calciner to the reheater chamber.

VERNON O. BOWLES. AUGUST H. SCHUTTE.

REFERENCES CITED The following references are of record in the file of this patent: V

UNITED STATES PATENTS

Claims

5. IN A CLOSED SYSTEM FOR THE CONTINUOUS CONVERSION OF HEAVY RESIDUAL OILS INTO COKE AND LIGHTER HYDROCARBONS BY APPLICATION OF SAID OILS TO A GRAVITY PACKED DOWNWARDLY MOVING COLUMN OF PREHEATED COKE PARTICLES, THE COMBINATION COMPRISING AN UPRIGHT REACTOR VESSEL HAVING A PARTICLE INLET AT ITS UPPER END AND A PARTICLE OUTLET AT ITS LOWER END, MEANS FOR FEEDING HEAVY RESIDUAL OIL INTO THE UPPER PORTION OF THE REACTOR VESSEL, MEANS FOR WITHDRAWING LIGHTER HYDROCARBONS FROM THE REACTOR VESSEL ADJACENT THE OIL FEEDING POSITION, MEANS FOR CONTROLLING THE PASSAGE OF COKE PARTICLES THROUGH SAID PARTICLE OUTLET, AN UPRIGHT PARTICLE REHEATER CHAMBER, SAID REHEATER CHAMBER HAVING A PARTICLE OUTLET AT ITS LOER END CONNECTED DIRECTLY WITH THE PARTICLE INLET OF THE REACTOR VESSEL, PARTICLE TRANSFER CONDUIT MEANS EXTENDING BETWEEN THE PARTICLE OUTLET OF THE REACTOR VESSEL AND THE INLET OF THE PARTICLE REHEATER CHAMBER, A PRODUCT PARTICLE DRAWOFF LINE IN SAID TRANSFER CONDIUT MEANS, A COKE PARTICLE CALCINER OF THE COMBUSTION TYPE CONNECTED IN SAID PARTICLE DRAWOFF LINE, AND ANOTHER LINE CARRYING THE PRODEND OF THE PARTICLE REHEATER CHAMBER, SAID REHEATER CHAMBER BEING PROVIDED WITH MEANS BELOW SAID UPPER END FOR REMOVING THE PRODUCTS OF COMBUSTION THUS SUPPLIED.