US2309112A - Production of fuel oils - Google Patents

Description

Jan. 26, 1943. E. J. HOUDRY ETAL.

PRODUCTION OF FUEL OILS Filed Feb. 16, 1959 5 R O T N E V m ATTORN EY EUBENELLHDUDRY ALBERT ILFETERKIN BY ,Qtd,

Patented Jan. 26, 1943 UNITED STATES PATENT OFFICE PRODUCTION GF FUEL OILS Eugene J. Houdry, Ardmore, and Albert G. Peterkin, Bryn Mawr, Pa., assignors to Hendry Proeess Corporation, Wilmington, Del., a corporation of Delaware .Application February 16, 1939, Serial No. 256,710

claims. (ci. 19e-5o) v This invention has to do with the conversion of very heavy and often almost worthless residual materials into more readily saleable or useful forms.

Among the materials to be treated are the great quantitiesrof tarry or heavy bottoms in crude oils as well as the residues from renery operations on petroleum, from the destructive distillation of carbonaceous deposits, etc. Such materials have only a limited sale for such uses asroong compounds, road oils, and the like.l

Coking operations are utilized to consume much of the -tarry material but the yields of gasoline 875 F. with the preferential range from 810 to are low and dimculties and delays are involved due to the frequent shut-downs which are necessary for the removal of the large deposits of coke. If the residues are to be disposed of directly as low grade fuel oil, they must be blended with very considerable quantities of light fuel oils or gas oils (which command a good price) in order to meet even bunker C speciiications. Another expedient is to subject residual material to a thermal viscosity breaking operation which is considerably milder in character than the previously mentioned coking operations, the purpose being to convert the heavy charge so far as possible into gas oil for'subsequent cracking and coking operations, but such viscosity breaking producesabout of gasoline of very low grade and octane rating as well as a lcorresponding or equivalent quantity of gas. Still another expedient is to prepare a vapor phase cracking charge-from such residual material by a contact vaporizing operation which consists in spraying the tar in heated condition and mixed with steam or other suitable gases or vaporsl upon hot highly porous inert contact material and letting the hydrocarbons gradually distill ofi', but this operation calls' for large quantities of steam or the like which must subsequently be removed and in addition lays down coky and resinous deposits in an uneven manner on and within the contact mass, thereby complicating the problem of regenerating the latter.

One object of the.,-invention is to improve known methods of disposing of very heavy hy.-

drocarbon -residues including those which are solid at room temperature. Another object is to devise a simple and economical way of converting heavy residues so as to meet fuel oil specilications. Another object is to provide suitable apparatus for eil'ecting the above objects. Still 850 F. Feed rates may vary anywhere from 11/2 1 (one and one-half volumes oi liquid charge per hour per volume of contact mass) to 10:1.

Suillcient pressure is utilized to keep all of the charge and most of the products of the reaction in liquid phase, as up to '150 lbs. per sq. in. Usually, the pressure need not exceed 500 lbs. per sq. in.; and, in many instances, lbs. per sq. in. is sufllcient. Y The operating conditions for each type of charge are adjusted so as to produce as little naphtha and gas as possible. 'I'he quantity of naphtha recovered in flashing the product to flash speciiications is normally not over 5% by volume of the charge and, injmost instances, it can be held to 2% or even less. Residues from asphaltic base crudes usually require somewhat higher temperature and/or lower feed rates than the residues from parafflnic or mixed base crudes.

The contact material will require regeneration from time to time to removefthe coky, resinous and other solid or semi-solid deposits which accumulate in the pores during the operation, hence for continuous operation two or more con# tainers or converters are utilized, so that at least one converter maybe on stream while the other or others are in regeneration. Any suitable form of regeneration may be utilized, burning being the most effective, with purging operations before and after by a vaporous medium or by vacuum and with occasional ilushing with a solvent after the burning operation, if desired. As

a preliminary step to regeneration, it is usually advantageous to lsend through-the converter a quantity of lighter` hydrocarbon material, such as a gas oil, for example, in :an amount substantially equal to the volume of the contact mass, to wash out of theconverter the heavier charge. Such washing material is preferably sent through the converter under the pressure of the operation, the pressure then being released to permit the gas oil 4or other lighter hydrocarbon material to vaporize and leave the converter. This step is not only important in preventing loss of charging material, but the wash oils may be incorporated directly with the products of the operation to make such adjustment as may be necessary to meet the desired fuel oil specifica,- tions. The quantity of lighter material needed for this purpose is readily determined during the usual laboratory tests which precede plant operations.

In order to illustrate the invention and the manner of its use, one concrete embodiment of apparatus for practising the same is indicated somewhat diagrammatically in the single figure of the accompanying drawing. The heavy residual material, heated sumcientlv to be fluid, is forced by pump I, which imposes enough pressure on the charge to retain it and subsequent products in liquid phase condition, as from 100 to 300 pounds per square inch, through a heater coil 2, where its temperature is raised to within the reaction range of approximately '775 to 875 F. 'Ihe rate of feed through coil 2, however, is made sufficiently high, within the range of 11/2z1 to 10:1, with due consideration to the characteristics of the charge, so that thermal cracking is substantially or practically avoided. The heated charge then passes by valved line 3 into the lower manifolding chamber 4 of converter 5, and is forced upwardly through the perforations in lower partition member 6 into and through the large central reaction chamber 1 which is completely lled with a mass M of highly porous solid contact material, in the form of bits, fragments or molded pieces, having little or no catalytic activity. The contact material may be silicious in character and may be formed after the manner disclosed in U. S. Patent No. 1,818,403, issued to Alfred Joseph on August l1, 1931. A similar material which is less inert in character may be prepared by taking about 90 parts of activated clay, such as California Superflltrol, with about l parts of a plasticizing medium such as Argosite (trade name for a high swelling'bentonite) to give strength, and with about 70 parts of material to product porosity, such as corn meal, these parts being-'thoroughly mixed and extruded inte 4 mm. pellets which are then heat treated to produce the desired low degree of catalytic activity, during which treatment the corn meal is burned out to give a high degree of porosity in the pellets. The products of the reaction pass from reaction chamber 1 through perforations in upper partition member 8 into upper manifolding chamber 9, whence they pass by valved branch I 0 into products line Il leading through cooler IIa to a flashing zone provided with flashing equipment of any known or suitable type, such as tower I2. Stripping steam may be sent into the lower part of tower I2 by line I3, this steam escaping with the released naphtha and gas through overhead line I 4, while the fuel oil, preferably adjusted to flash specifications, issues from tower I2 by bottom outlet line I5.

To insure accurate temperature control of contact mass M ln converter 5, a heat exchange and an outer manifold member IIb with which the outer conduits I 6b connect. The heat exchange circuit further consists of a heat exchanger |8 and a pump I9 for circulating the heat exchange medium, which may be a fluid of any suitable or desired type, either gaseous or liquid. With the temperatures for the present operation, liquids such as water, fused salts, mercury, diphenyl, or metals or metallic alloys having low melting points, are most suitable. The heat exchange medium supplies heat to contact mass M, during the on-stream or viscosity breaking operation, to maintain the entire mass at suitable temperature, and extracts heat from the mass during the alternating regenerating period, when the deposit on the mass is burned away to prepare for another on-stream operation.

After a suitable period of operation, the charging of heavy bottoms is interrupted in order to regenerate contact mass M. As a preliminary step to the regeneration, the mass is purged of the charge. This may be effected by sending steam into the case. as through upper valved branch line 20, the dislodged fluid being vented through a lower valved line 2| serving as a drain. However, if the charge to be converted is very heavy, or if the viscosity breaking has not been sufficient to meet fuel oil specifications, it is advantageous to adjust the products by washing out the converter with a lighter hydrocarbon material, such as a gas oil, which may be charged to the converter under the same or similar pressure and temperature conditions. In many insystem is provided, consisting of nested heat exchange units I6 embedded in the contact mass M in symmetrical arrangement throughout the entire reaction zone, each unit consisting of an inner conduit Ilia and an outer conduit I6b which may be provided with fins (not shown). The conduits connect with manifold units I1 in upper manifolding chamber 9, which manifold units comprise an inner manifolding member Ila. supplying inner conduits Ita of nested units I6,

stances, only a limited amount of such wash oil is needed, as, for example, an amount approximating the volume of contact mass. While such gas oil used for the washing medium can be sent through the pump and heating equipment fox-the normal charge, it is preferable to utilize a separate pump 22 and coil 23, which coil may be in the same heater or still as coil 2, as indicated in the drawing, or in a separate heater. The pressure and temperature conditions are preferably identical or at least similar to the operation with the heavier charge. The heated wash oil then passes by valved branch 24 into and through converter 5, and thence to ash tower I2 in the same manner as the normal charge. The wash oil may be mingled with the charge during .the period in which the latter is being shut off from the converter. Alternatively the gas oil may be introduced at the top of the converter, as by line 20, to displace the contents of the converter through line 2I to pass into products line II before cooler Ila, by suitable cross-over connections (not shown). After this limited washing operation, the pressure in converter 5 is released and the converter is permitted to drain by gravity into a suitable tank or container (not shown) to recover all hydrocarbons which will leave as vapor or as liquid. The converter is then steamed or subjected to vacuum purging, as through line 20, and thereafter a regenerating medium, such as air or other oxygen containing gas, is sent by line 25, preferably in heated condition and under pressure, to effect controlled burning of the deposit on the contact mass M, the fumes escaping through valved branch line 26 from the upper end of the converter. After the burning operation is completed, the converter is again purged by steam or by vacuum, and is ready to be put back on stream for another viscosity breaking operation. From time to time, it may be necessary, as a final stage in the regenerating operation, to utilize inlet line v2l) and drain 2| to eiect solvent washing of the mass M by water, dilute acids. or other media, to extract from the mass salts or other contaminants which cannot be removed by the burning operation, as disclosed, for example, in Patent No. 1,957,649, issued May 8, 1934, to Eugene Houdry. i

While it is possible to operate the process with a. single converter. such as 5, there are obvious advantages in conducting the viscosity breaking operation as a continuous process. To eiect a continuous operation, two or more converters 5 will be necessary, so that one o1- more may be utilized for the viscosity breaking operation while the other or others are in regeneration. To indicate continuous operation, two converters 5 are shown in the drawing, but the second requires no detailed description, since it is a mere duplication of the other. The converters 5 and the various lines will be lagged or J'acketed'to prevent heat losses, but such obvious expedients are not indicated, since they form no part ofthe present invention.

The use of the invention in handling very heavy residual charging material is illustrated bythe following examples:

Example 1 An 8.1% tar bottoms from a mixture of Mid- Continent and East Texas crudes had the following characteristics:

Flash P. M. C. C F 225 Say. U. Vis. at 210 F 734 Pour point, F +110 Gravity, A. P. I 12.6

To bring the above -material to bunker C speciiications, it was found necessary to add 54 parts ditions .to Wash out the converter; the products of the gas oil washing were added to the products of the viscosity breaking operation to give 102 parts of fuel oil of' the following characteristics:

Flash, P. M. C. C 154 Furol viso. at 122 F 159 Pour point, F +25 Gravity, A. P. I 14. 5

There was also produced:

2.1% by volume of naphtha (recovered by ashing -to flash specifications) 1.5% by weight of gas oi 1.12 sp. gr.

0.4% by weight of coky deposit which was burned oilr in the subsequent regenerating opertion.

Hence by employing the viscosity breaking o'peration, there was effected a net saving of 49 parts of gas oil (54 parts without viscosity breaking as comparedr with 5 parts after viscosity breaking) per 100 parts of tar.

The gas oil used for blending purposes was recycle stock from a cracking operation on a blend of East Texas crudes.

Example 2 A 32% tar bottoms from Venezuelan (Lagunillas) crude had the following characteristics:

Say. U. Vis/210 F T-- Too heavy. Pour point Over (+120). Gravity 3.4.

To bring this material to bunker C specifications, 122 parts of gas oil per 100 parts of tar were needed.

The tar without steam or other added material was subjected to the catalytic viscosity breaking operation at 840 F. temperatureand under a pressure of 300 lbs. per sq. in., at a feed rate of 2:1 for a two hour period. Only 31 parts o1 gas oil were then needed per 100 parts of tar to make 125 parts of bunker C fuel oil, a part of this gas 20 oil equivalent to the catalyst volume of lthe converter being charged through the latter under the specified operating conditions to free the contact mass of the heavy charge. The blended fuel oil product had the following characteristics:

Flash, P. M. c. c F. 156 Furo1visc./122 F 147 l Pour point, F +20 Gravity; A. P. I 9.8

There was also produced:

1.6% by volume of 62.0 A. P. I. naphtha (recovered by flashing to ash specifications) 4.6% by weight of gas (1.15 sp. gr.)

2.4% by weight of .coky deposit to be burned of! in the subsequent regeneration of the contact mass.

` By 'using viscosity breaking, a saving of 91 parts of gas oil (122 parts without viscosity 40 breaking as compared with 31 parts after viscosity breaking) was effected. I

From the above, it will be apparent that the present invention provides a simple and economical method of converting substantially worthless heavy residual material into salable fuel oils, without the problem of disposing of large quantities of petroleum coke. By utilizing two or more converters, a continuous operation is effected without any necessity of frequent dismaitling to clean out the reaction chambers, as is required in conventional thermal coking plants. The process operates with a high charging rate, and produces only a relatively small amount of coke which is immediately burned during the alliberated not being wasted, but being directly recoverable in the forms of power, heat and steam. The contact mass filters out sediment, and is highly efiicient as a selective viscosity breaking agent, since so little naphtha, namely, of the or der of A2% by volume, is recovered. The contact mass also localizes the deposition of coke on the contact mass whence it is periodically removed by burning, prevents its deposition and accumulation in pipes, valves and other parts of the equipment, and so enables continuous uninterrupted operation under wide variation of operating conditions. Definite and practical advantages reside in the use of gas oil both as washing medium and as a medium for 'effecting final adjustment of the products 'to fuel oil specifications; its use, however, may be minimized or even entirely avoided by recirculating or recycling a part of the products, or by making a less deep 75 cut when the original charge is prepared.

Flash, P. M. c. c 380 F.

ternate regenerating operations, the energy thus We claim as our invention:

1. In the conversion of tars and similar residues into commercial fuel oils, the process steps which comprise sending the charge in heated condition and in liquid phase through a reaction chamber containing highly porous silicious contact material of low catalytic activity, maintaining the chamber under suflicient pressure to insure liquid phase operation, holding the contact material at conversion temperature and adjusting the feed rate to produce only'a small quantty of naphtha, after a period of operation substituting for the heavy charge a quantity of lighter hydrocarbons in the gas oil boiling range substantially equivalent to the volume of the contact mass and'sending it through the reaction chamber under the same operating conditions to flush the contact mass as a preparatory step to regenerating the same, limiting the on-stream operation with heavy charge to such a period that the combining of the products of the heavy charge and of the substitute charge meets fuel oil specifications, mingling the products of both charges to form a commercial fuel oil, then freeing the contact material of coky, resinous and other deposits by a regenerating operation, and repeating the above steps.

2. In the conversion of .tars and similar residues into commercial fuel oils through the action of solid porous contact material which has to be freed from time to time of coky and resinous deposits in order that the converting reaction may be continued, the process steps which comprise sending the charge in heated condition and in liquid phase through a reaction chamber containing the porous contact material, maintaining the chamber under a pressure of at least 100 lbs. per sq. in. during the on-stream operation, holding the contact material at a conversion temperature.

and adjusting the -feed rate to produce only a small quantity of naphtha and finally adjusting the products of the reaction to meet fuel oil specifications by substituting for the charge a predetermined quantity of lower boiling oil which is sent through the reaction chamber under the same operating conditions and is added to the aforesaid products, and then regenerating the contact material in preparation for another onstream operation.

3. In the conversion of tars and similar residuessinto commercial fuel oils through the action o-f solid porous contact material, the process which comprises ending the charge at a temperature at least as high as 775 F. in liquid phase and under pressure through a reaction zone lled with the porous contact material at such rate as to produce only a small quantity of naphtha, continuing the feeding of the charge until the reaction is impaired by the deposition of coky, resinous and other contaminants on the contact material, and then prior to regenerating the contact material by oxidation feeding to the reaction zone a limited quantity of oil in the gas oil boiling range to act as a flushing medium, and addlng the resulting hydrocarbons to the products of the on-stream operation to adjust the same to meet mel oil specications;

4. In the conversion of tars and similar residues into commercial fuel oils through the action of solid porous contact material, the process which comprises sending' the charge in heated condition and under suilicient pressure to maintain it in liquid phase through a reaction zone filled with porous but substantially inert contact material and maintained within the temperature range of 810 to 850 F.; adjusting the feed rate with relation to the gravity and other characteristics of the charge so that the reaction produces only a small quantity of naphtha. continuing the feeding of the charge until the reaction is impaired by the deposition of coky. resinous and other contaminants 'on the contact material, then changing the charge to lower gravity hydrocarbons of the gas oil type but maintaining the same operating conditions, limiting the quantity of such lower gravity hydrocarbons to an amount requisite to flush the contact mass as a preparatory step to regenerating the same and to adjust the products of the reaction to fuel oil or Bunker C specifications, and mingling the products of both changes to form a commercial fuel oil.

5. In the conversion of tars and similar residues into commercial fuel oils through the action of solid porouscontact material which has to be freed from time to time of coky and resinous deposits in order ,that the converting reaction may be continued, the process steps which comprise sending the charge in heated condition and in liquid phase through a reaction chamber containing the porous contact material, maintaining the chamber under a pressure of at least 100 lbs. per sq. in. during the on stream operation, holding the contact material at a conversion temperature and adjusting the feed rate to v said first reaction chamber to flash of! the lower boiling oil, regenerating the contact material in said rst reaction chamber by freeing it of coky and resinous deposits, then restoring the feeding EUGENE J. HOUDRY. ALBERT G. PETERKIN.

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