US2482137A - Process and apparatus for converting hydrocarbons - Google Patents

Description

Sept. 20, 1949. A. H. SCHUTTE PROCESS AND APPARATUS FOR CONVERTING HYDROGARBONS 2 Sheets-Sheet 1 Filed Feb. 13, 1945 f eed INVENTOR. w/yJk/zl/he S 20, 1949, A. H. SCHUTTE PROCESS AND APPARATUS FOR CONVERTING HYDROCARBONS Filed Feb. 15, 1945 2 Sheets-Sheet 2 Sakai/a INVENTOR.

ATTORNEY Paten Sept 1949 PROCESS AND APPARATUS FOR CON- VERTING HYDROCARBON S August Henry Schutte, Hastings on Hudson, N. Y.,

assignor to The Lummus Company,

New York,

N. Y., a corporation of Delaware Application February 13, 1945, Serial N 0. 577,707

12 Claims.

This invention relates to hydrocarbon conversion and, in particular, to the formation of coke concurrently with the vaporization and cracking of heavy hydrocarbons such as bottoms and hydrocarbon residuals wherein the coke formed in the aforesaid reaction is deposited in the pores of the discrete particles of a free-flowing nonagglomerating solid phase bed moving continuously, by gravity alone, through a reactor or reactionzone wherein the reaction is accomplished or carried out.

It is an object of this invention to provide a new and improved method for securing the deposit of coke as aforesaid to the optimum degree without occurrence of bed agglomeration, and new and improved reactor structures for the accomplishment of the aforesaid method.

It is a further object of this invention to provide such a process wherein the production of undesirable products is minimized and wherein the valuable products are obtained in readily recoverable form.

These and other objects and advantages of this invention will hereinafter appear from the following description taken with the drawing.

In the drawing:

Fig. 1 is a view in elevation, and partly broken away, of a reactor constructed according to this invention for accomplishment of the method thereof;

Fig. 2 is a view, in elevation, of a modified reactor embodying multiple feed and coking zones for carrying out the method of this invention; and

Fig. 3 is a section taken substantially on the plane indicated by the line 3-3 in Fig. 1.

Heretofore, the disposition of heavy hydrocarbon by-products of cracking, distillation, and like operations, comprising bottoms, tars, and the like, has represented a major operating problem in the petroleum industry. While it has been recognized that the conversion of a part of these by-products into coke, along with the formation of useful and valuable convertible products would solve this problem, at least to a large degree, all

former attempts have resulted in the use of ex-,

pensive, complicated and cumbersome mechanisms difiicult to service and of relatively low efiiciency. According to this invention the use of coking drums, mechanical conveyors, grates and other like coke deposit receiving mechanisms is totally obviated.

The heavy hydrocarbon feed is spread or distributed on the moving particles of a solid phase or compact, free flowing gravity bed made up of discrete porous solid particles, the pores of the particles receiving substantially all ofthe coke deposit whereby lumping, agglomeration or sticking together of the bed particles is obviated. This sticking is avoided by limiting the spread density of the feed upon the particles in such manner that that portion of the feed which does not flash off or evaporate upon contact with the hot bed particles (the sensible heat of which furnishes the coking heat or a major portion thereof) does not exceed in volume the pore volume of the discrete bed particles.

Thus, upon spreading the feed upon the bed particles a part thereof is flashed off or evaporated upon contact with the hot bed particles and withdrawn as useful vapors which may be taken off, for further processing, to any suitable station. The remainder of the feed which does not flash off or evaporate is taken up or received by the pores of the particles substantially entirely whereby formation of sticky films between the discrete bed particles sufllcient in depth or thickness to destroy the free flowing properties of the bed is totally obviated.

No oxygen or oxygen containing gases or vapors are present at any point in this reaction. Therefore, no oxidation can occur and there is no flue gas and no other combustion products to be concerned with in the reaction described or in the recovery and/or processing of the vaporous products taken out by the vapor outlet. The presence of such oxygen containing vapors or gases along with flue gas, heretofore almost universally present in attempts at bed coking of residual liquid hydrocarbons, has precluded adequate tempera ture control in the coking reaction zone and rendered difllcult the recovery and/or processing of the vaporous products of the coking reaction.

Furthermore, the vapors produced by the invention herein described contain gasoline fractions formed by short-time high temperature contact and therefore have a far higher octane number than gasoline fractions produced by conventional coking methods employing long-time, low temperature soaking as in "drum coking and the like.

Experiments show the octane number improvement to be on the order of ten (10) to fifteen (15).

Referring to the drawing in detail, and with reference particularly to Figs. 1 and 3, the reactor is generally designated I 0 and is shown, for purposes of illustration, as comprising a tank-like elongated enclosure having a cylindrical wall I l and frusto-conical end portions contheir pores to any suitable tinuing therefrom and designated I2 and I4, respectively. Leading into the top frusto-conical end portion I2 is the inlet I through which the I heatedsmrous bed particles are fed, as hereinafter described, to form a free flowing gravity bed within the pores of the discrete particles 'of 'steadying the spreaders or distributors 28 and which coke is deposited, as hereinafter described. A suitable outlet I8 extends from the lower frusto-conicai end portion I4 and termnates in the delivery duct or outlet ll which delivers the bed particles, with coke deposits in collection station. The lower end of the reactor I8 is provided with suitable known means (not shown) for controlling the rate of feed or passage of bed particles uniformly through the reactor III.

Leading into the frusto-conical end portion I2 adjacent its junction with the inlet I5 is a sealing steam inlet I8- through which sealing steam is applied to the interior of the reactor I8 to prevent the passage of cracked vapors and the like upwardly through the bed material and out.

the inlet I5. A similar sealing steam inlet I9 is provided at the junction of the frusto-conical end portion I4 and the outlet I6 to prevent the passage of vaporous products downwardly out of the reactor I8 with the bed particles and coke deposits issuing from the outlet I'I. As shown, the interiors of the frusto-conical end portions I2 and I4 are lined with insulation 28 and similar insulation 2! is provided in the interior of the outer shell of the cylindrical portion of the reactor I0, being arranged between the metallic outer shell of that portion and a generally cylindrical interior metallic lining 22. Suitable clips 23 are provided for supporting the inner lining! 22 and the wall or baffle 24, as shown in Figs. 1 and 3.

At its upper terminus, the metallic liner 22, which prevents abrasion of the walls by the downwardly passing bed material, terminates at the wall or baflle 24 provided with a plurality of apertures 25 opening into down pipes or conduits 26 which extend into the hydrocarbon feed and vapor release space or conversion zone below the wall or baflle 24 and provide substantially uniform distribution of the bed material fed through the baffle 24. The vapor outlet 21 extends from the feed and vapor release space on the interior of the reactor I8 immediately below the wall or ,bafiie 24 to any suitable collecting station to which it is desired to convey the vaporous products of the reaction occurring within the reactor Ill.

The feed spreading mechanism comprises a' plurality of perforate pipe-like conduits 28, all connected with a common header 29, the said header having one end thereof closed by a plate 38, and the other end of the header 28 being connected to any suitable source of heavy hydrocarbons comprising the feed material desired to be spread in the pores of the bed material through the perforations of the feed distributors or spreaders 28, these conduits or spreaders 28 being preferably closed at the ends remote from the header 29.

In order to clean or service the feed distributors, or spreaders 28, for instance by cleaning the apertures thereof, the assembly comprising the header 29 and attached conduits or spreaders 28 is removable axially of the conduits 28 as a unit from the, interior of the reactor, the feed spreaders or distributors 28 having plates 3| welded thereto in suitable location and each plate being adapted to engage the outer flange of a addingstrength and rigidity to the wall 24.

As shown in Fig. 3, the spreaders or distributors 28 are preferably located between adjacent transverse rows of apertures and depending downpipes 26. This provides a free space for hydrocarbon-feedand-vapor release immediately beneath'the bafiieor wall 24 which collects the vaporous products of the reaction occurring when the hydrocarbon feed material is contacted with the hot porous moving bed particles issuing from the downpipes 28, as shown in Fig. l. The feed spreaders Or distributors are located within this space and the heavy hydrocarbon material comprising the feed is allowed to pass from the apertures in the spreaders or distributors 28 in relatively fine streams (as distinguished from atomizing sprays) to the particles which are moving down as flowing piles over and within the frusto-conical portions of the bed (i. e., the cones of repose) immediately adjoining the bed material in the interior of the downpipes 26,

-whereby the feed is applied to the discrete bed particles when they are undergoing movement in the aforesaid cones of repose or flowing piles.

It will clearly appear from the above that I have provided an extremely simple reactor for performing the method described above which reactor is of relativelycheap construction, simple, readily, and conveniently serviced since the most .frequently necessary operation of cleaning the spreaders for distributors 28 may be readily achieved by unbolting the plates 3i from the outer flanges of the nozzles 32, sliding the header and attached spreaders or distributors 28 outwardly with respect to the reactor, whereupon the said apertures may be readily and conveniently cleaned or unstopped, whereafter the feed assembly may be restored to the position shown inFig. 3 and bolted in that position by means of the' bolts, connecting the plates 3i and the outer flanges of the nozzles 32.

Ineoper ting the above structure to perform themethod eretofore described, ,bed particles from s" ito-.%"- major dimension in lump, pellea/or. extruded form, are fed-by suitable means (not shown)? into the inlet I5 at from 800 F. to l,30l F-; -introduction temperature, and preferably 'at :from 850 F. to 1050 F. introduction temperature;

The bed particles may comprise any one, or a mixture of more than one, of the class of known inert porous. contact materials including Koppers coke, petroleum coke, Alundum, Carborundum, pumice, crushed fire brick, p0-

rous ceramic particles, or spent crackin catalyst particles or beads." The bed particle porosity is preferably from 5% to 50% by volume, 1. e., for a given unit of gross volume in any one discrete bed particle, from 5% to 50% of that volume would represent pore volume.

The feed comprises such heavy hydrocarbons as bottoms, heavy petroleum residues, and hydrocarbon residuals, especially those resulting from other petroleum refining operations such as cracking, distillation, topping, etc. This feed is injected at from F. to 1,000 E, and preferably at from 700 F. to 900 F. It is spread upon the moving particles as described above, to prevent any part of the feed issuing or streaming the bed material above the vapor outlet 27..

while the sealing steam injected at the lower end of the reactor through the sealing steam inlet l9 displaces .the hydrocarbon vapors in the voids of the bed to prevent vaporous or gaseous products from leaving the reactor with the coke carrying bed particles. The temperature of the lastdescribed bed particles issuing from the reactor is from 800 F. to 1,000 FL, and the coke deposited on the outgoing bed particles represents from /z% to 10% is preferably in weight.

The operating pressure in the converter I is relatively low ranging between 2 lb. p. s. i. and 60 lb. p. s. 1., depending on the pressure required on the product vapors for subsequent processing.

To initiate operation of the structure shown in Fig. 1, porous bed particles of the above described type are fed into the reactor at the above described admission temperature range until the reactor is filled substantially to the degree shown in Fig. 1.

Sealing steam is then admitted through the inlets l8 and I9 and the feed turned on low, and then raised to the range above described and within the above described concept in order that the unfiashed oil will be substantially all taken up in the pores of the discrete bed particles, so that the overflow from these bed particles shall remain low enough to be inconsequential, for prevention of agglomeration in the bed.

In the bed feed zone above the baiiie or wall 24, the particles are dry, with their pores substantially empty and tree or foreign matter, coatings or deposits. These particles are within the temperature range described above. Upon passing downwardly through the downpipes 26 they enter the frusto-conical masses comprising the cones of repose wherein they are in substantial movement. At this time hydrocarbon liquid (supplied by the spreaders 28 in fine streams) is spread upon the moving discrete particles whereupon the unvaporized portion of the feed enters (and is substantially completely received by) the pores of the discrete bed particles.

The vaporized orflashed portion of the hydrocarbon feed which is produced substantially simultaneously upon bed-feed contact is released into the space communicating with the vapor outlet 21 through which it is taken out for collectlon and/or further processing along with the vapors resulting from progressive cracking occurring later during travel of the spread particles downwardly, as described hereinafter.

As these loaded bed particles pass downwardly by gravity as a column of greater horizontal cross sectional area than the streams through the body of the reactor l0, sufllcient residence time is provided for the coking reaction to proceed to completion or, in other words, for the liquid hydrocarbon load in the pores of the bed particles to be thermally converted or cracked into lighter hydrocarbon vapors which pass up through the bed to the vapor outlet 21 leaving a residue of dry coke deposited in and only partially filling the pores of the discrete bed particles. The particles in this condition pass out of the reactor through the outlet l1.

by weight of the particles, and the neighborhood of by 76 the unflashed feed material in the particle pores The above mentionedresidence time at normal operating temperatures may range from 10 to 30 minutes.

In the reaction described above the prolonged contact of the hydrocarbon feed with the hot porous bed particles results in the production of coke deposits in the pores of the discrete bed particles concurrent with the production of vaporous products resulting directly from the thermal eil'ect of this contact. The vapors taken of! through the vapor outlet 21 comprise vapors of this type (with the exception of a slight amount of sealing steam supplied through the steam inlets l8 and 19), i. e., the light fractions evaporated ofi or flashed off upon initial feed-bed contact and also those vaporous fraction resulting from the progressive cracking occurring during passage of the particles downwardly through the bed below the feed spread zone.

Due to the above described method of operation and to the depth of the bed of porous particles in the coking zone below the feed point an unique and valuable effect is secured because, as the heavy hydrocarbon liquid in the pores of the bed particles is gradually reduced to a coke residue, the vapors evolved are subjected to increasing cracking time in their passage through the bed of particles on their way to the vapor outlet 21. Thus the earlier evolved vapors are not overcracked and the final portions of vapor evolved just before the liquid pore deposit goes to dryness are cracked suillciently to be satisfactorily reduced in boiling range to a condition suitable for further processing. This selective cracking eflect on the vapors evolved by the coking reaction cannot be obtained in methods employing either coking drums or shallow coking zones. Furthermore, at the solids entrance temperatures usually employed, a portion of the hydrocarbon feed vaporizes immediately on contact with the bed particles. This vaporization is more extensive and less destructive than that which could be obtained b conventional means such as fired heaters. Because of the above advantages, it is possible to secure higher yields of valuable vaporous products with less degradation of the charge to undesirable products such as coke and gas.

The above described cycle is continuous, i. e., the amount of bed material fed into the inlet I5 substantially balances the output of the outlet or delivery I! and it is, of course, to be understood that any suitable known means may be provided to maintain this .balance such as the structure shown in co-pending applications of August Henry Schutte et al., S. N. 514,192, filed December 14, 1943, now U. S. Patent 2,390,031, patented November 2'7, 1945, for Hydrocarbon conversion.

A modification of the structure shown in Fig. 1 is illustrated in Fig. 2 wherein the feed means, vapor outlet and walls or bafiles 24 are in multiple, the corresponding reference numerals in Figs. 1 and 2 indicating corresponding parts. This em bodiment of the reactor permits multiple saturation of the porous :bed particles by the heavy unfiashed feed material before the bed material and deposited coke are removed from the outlet or delivery IT. This is particularly advantageous where itis practical to introduce more sensible heat with the bed solids than would be required to carry out the conversion of the unflashed feed material in the particle pores in a single contact. These additional zones are preferably so spaced from each other, that sllfllcient residence time is achieved for substantially complete drying out of Means? and the completion of the coking reaction before the particles are contacted with further unflashed feed material in the succeeding zone. While the illustrative structure of Fig. 2 shows two such zones, it is, of course, to be understood that these zones may be further multiplied where the sensible heat of the bed material upon admission is sufliciently high to ensure the residence of sutflcient sensible heat in the bed material'when it reaches the last aforesaid zone.

1 It is, of course, to be understood that the above description is merely illustrative and in no wise limiting, and that I desire to comprehend within my invention such modifications as are included within the scope of the following claims.

I claim:

1. In a process for conversion of liquid hydrocarbon in the presence of a substantially compact therefrom, a battle dividing we enclosure mm a bed feed zone thereabove and a hydrocarbon of repose of bed material below the baflle with said cones joining at their lower ends and 'form- 7 ing a free vapor collection space between their j sides and the under side of said bailie, a vapor column of moving particle-form solid contact material moving through an upright conversion zone, the method for introduction of contact material and liquid hydrocarbon charge to said conversion zone which comprises: introducing particle-form solid contact material into the upper section of said conversion zone in a plurality of confined streams of downwardly moving particles V delivering onto the surface of said column as a series of flowing piles assuming approximately the angle of repose, and applying a stream of liquid hydrocarbon charge to the discrete bed particles of each stream laterally between the streams and while in their movement as flowing piles.

2. In a process for conversion of liquid hydrocarbon in the presence of a substantially compact column of moving particle-form solid contact material moving through an upright conversion zone, the method for introduction of contact material and liquid hydrocarbon charge to Isaidconversion zone which comprises: introducing particle-form solid contact material into the upper section of said conversion zone in a plurality of confined streams of downwardly moving particles delivering onto the surface of said column as a series of flowing piles assuming approximately the angle of repose, and applying a stream of liquid hydrocarbon charge to the discrete bed particles on opposite sides of the flowing piles and while in their movement as flowing piles.

3. The method of converting a charge of heavy liquid hydrocarbons, which comprises passing by gravity alone, a compact column of particle form tact material into the upper end of said conversion zone in a confined stream of appreciably less cross-sectional area than said compact coioutlet communicating with said space for withdrawing vaporous products of the reaction therefrom, and a plurality of feed distributing means projecting into said space for spreading heavy liquid hydrocarbon feed material in streams on the bed material in said masses.

5. A reactor for converting heavy hydrocarbons into vaporous products and coke deposits on discrete solid particles of a solid phase free flowing contact material vertically downward through an i elongated conversion zone, introducing said conumn to form upon release a flowing pile of coni j tact material extending to the upper end of said column and defining a vapor collection space at the top of said conversion zone, directing streams of heavy liquid hydrocarbon charge into opposite 'sides of the top portion of said flowing pile of contact material adjacent the lower end of said confined stream, and removing the vaporous products of the reaction from said vapor collection space.

4. A reactor for converting heavy hydrocarbons into vaporous products and coke deposits on discrete particles of a solid phase free flowing gravity bed, which comprises an upright enclosure having at its upper end an inlet for incoming bed material and having an outlet at its lower end for delivering bed material and coke deposits gravity bed, which comprises an upright enclosure having at its upper end an inlet for incoming bed material and having an outlet at its lower end for delivering bed material and coke deposits therefrom, a bailie dividing said enclosure into a bed feed zone thereabove and a spreading and coking zone therebelow, means including a plurality of downpipes communicating with both sides of said baflle for distributing bed material passing downwardly therethrough, said downpipes being spaced to form a plurality of generally frusto-conical masses of the flowing bed material therebelow with said masses joined at their lower ends and forming a free vapor collection space between their sides and the under side of said bafiie, a vapor outlet communicating with said space for withdrawing vaporous products of the reaction from said reactor, and a plurality of perforate pipe like feed distributors projecting transversely into said space for spreading heavy hydrocarbon feed material in streams over the bed material in said masses.

6. A reactor for converting heavy hydrocarbons into vaporous products and coke deposits on discrete solid particles of a solid phasefree flowing gravity bed, which comprises an upright enclosure having at its upper end an inlet for incoming bed material and having an outlet at its lower end for delivering bed'material and coke deposits therefrom, a baflle dividing said enclosure into a bed feed zone thereabove anda spreading and coking zone therebelow, means including a plurality of down pipes communicating with both sides of said baflle for distributing bed material passing downwardly therethrough, said downpipes being spaced to form a plurality of generally frusto-conical masses of flowing bed material therebelow with said masses joined at their lower ends and forming a free vapor collection space between their sides and the under side of said baille, a vapor outlet for withdrawing vaporous reaction products from said space, and a plurality of perforate pipe like feed distributors probed material passing downwardly therethrough,

said downpipes being spaced to form a plurality of generally frusto-conical masses of the flowing bed material therebelow with said masses joined at their lower ends and forming a free vapor collecting space between their sides and the under side of each baiiie, a vapor outlet for withdrawing vaporous reaction products from each of said spaces, and a plurality of perforate pipe like feed distributors projecting into each space for spreading heavy hydrocarbon feed material in streams over the bed material in said masses.

8. A reactor for converting heavy hydrocarbons into vaporous products and coke deposits on discrete solid particles of a solid phase free flowing gravity bed, which comprises an upright enclosure having at its upper end an inlet for incoming bed material and having an outlet at its lower end for delivering bed material and coke deposits therefrom, a plurality of baflles dividing said enclosure into a bed feed zone and a series of spreading and cokin zones, means including a plurality of down pipes communicating with both sides of each baifle for distributing bed material passing downwardly therethrough, said downpipes being spaced to form a plurality of flowing cones of repose of bed material therebelow with said cones joined at their lower ends and forming a free vapor collection space between their sides and the under side of each bafile, a plurality of vapor outlets for separately withdrawing vaporous reaction products from said spaces, and a plurality of perforate pipe like feed distributors projecting into each space for spreading heavy hydrocarbon feed material in streams on the particles of bed material in said cones, said perforate feed distributors being removable for cleaning the perforations thereof.

9. A reactor for converting heavy liquid hydrocarbons into vaporous products and coke deposits on discrete particles of granular material forming a gravity-packed free-flowing bed which comprises an upright enclosure having an inlet at its upper end for incoming bed material and having an outlet at its lower end for delivering bed material and coke deposits therefrom, a baiile dividing said enclosure into a bed feed zone thereabove and a hydrocarbon spreading and coking zone therebelow, said baflle having a plurality of conduits communicating with both sides of the baffle for distributing bed material passing downwardly therethrough, said conduits restricting the flow of bed material and thereby forming a plurality of flowing piles of bed material below the baflie with said piles joining at their lower ends and forming a free vapor collection space between their sides and the under side of said bailie, a vapor outlet communicating with said space for withdrawing vaporous products of the reaction therefrom, and a plurality of feed distributing means projecting into said hydrocarbon spreading and coking zone for spreading heavy liquid hydrocarbon feed material in streams on the bed particles while undergoing movement in said piles.

10. A reactor for converting heavy liquid hydrocarbons into vaporous products and coke deposits on discrete particles of granular material forming a gravity-packed free-flowing bed which comprises an upright enclosure having an inlet at its upper end for incoming bed material and having an outlet at its lower end for delivering bed material and coke deposits therefrom, a bailie dividing said enclosure into a bed feed zone thereabove and a hydrocarbon spreading and coking zone therebelow, said bafile having a plurality of openings communicating with both sides of the baille for distributing bed material passing downwardly therethrough, said openings restricting the flow of bed material and thereby forming a plurality of flowing piles of bed material below the bailie with said piles Joining at their lower ends to form the bed, a plurality of hydrocarbon feed distributing means projecting into said hydrocarbon spreading and coking zone for spreading heavy liquid hydrocarbon feed material in streams on the bed particles while undergoing movement to said bed, and a vapor outlet communicating with said hydrocarbon spreading and coking zone for products of the reaction.

11. The reactor as claimed in claim 10 in which the hydrocarbon feed distributing means are mounted below the baflle and between the openings forming flowing piles of bed material.

12. A reactor for converting heavy liquid hydrocarbons into vaporous products and coke deposits on discrete particles of granular material forming a gravity-packed free-flowing bed which comprises an upright enclosure having an inlet at its upper end for incoming bed material and having an outlet at its lower end for delivering Y bed material and coke deposits therefrom, a

coking zone therebelow, said bafile dividing said enclosure into a bed feed zone thereabove and a hydrocarbon spreading and baflle having a. plurality of conduits communicating with both sides of the baille for distributing bed material passing downwardly therethrough, said conduits restricting the flow of bed material and thereby forming a plurality of flowing piles of bed material below the baflle with said piles joining at their lower ends to form the bed, a plurality of hydrocarbon feed distributing means projecting into said hydrocarbon spreading and coking zone under the bailie and between the conduits thereof for spreading heavy liquid hydrocarbon feed material in streams on the bed particles while undergoing movement to said bed, whereby the liquid hydrocarbon is fed at points out of the paths of the moving particles, and a vapor outlet communicating with said hydrocarbon spreading and coking zone for withdrawing the vaporous products of the reaction.

AUGUST HENRY SCHU'I'IE.

REFERENCES CITED The following references are of record in the withdrawing the vaporous

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