JPH0250156B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION This invention relates to fluid catalytic cracking of hydrocarbons. More specifically, the present invention provides a standpipe reactor in which:
The present invention relates to an improved method for dispersing a liquid hydrocarbon feed in a stream of heated catalyst particles to promote catalysis between the hot catalyst particle surfaces and finely divided liquid droplets. A particular object of the present invention is to enable the finely divided hydrocarbon liquid droplets to come into direct contact with the hot catalyst particle surface, rather than contacting the liquid surface on the catalyst or the gas emanating from the liquid. be. Such contact between the droplets and the hot catalyst is facilitated by arranging at least one mist-generating hydrocarbon spray nozzle for discharge into the standpipe reactor. According to the invention, this misting nozzle has a pivot or centrifugal chamber.
This chamber is directly adjacent to a full flow area orifice having a diameter substantially less than the diameter and area of the swirl chamber or the hydrocarbon liquid supply line connected thereto. at least one pair of vanes having a pitch of at least 20° with respect to the axis of said supply line and chamber, causing a swirl or centrifugal rotation to the liquid entering the chamber, except that the diameter of the orifice is small; There should be nothing blocking the flow,
It is thereby desirable to convert the entire feed into a mist and feed it to the standpipe reactor. Desirably, the area of the orifice is substantially equal to the area of flow through the vane. A plurality of such nozzles are arranged at equal intervals around the circumference of the standpipe reactor and are recessed from the catalyst flow area to protect the nozzles from erosion and direct heating by the thermal catalyst. desirable. However, this recessed arrangement within the wall of a standpipe reactor does not allow for the flow of fluid from the orifice into the catalyst stream, or to disperse the flow into finely divided liquid particles to produce the desired mist. It is only effective when the formation is not obstructed by walls. Such finely divided droplets are more rapidly vaporized from liquid to gas by direct contact with the heated catalyst particles, so that the gap between the gas and the catalyst surface is smaller than in the pyrolysis of hydrocarbons. Contact reaction takes precedence. Since the catalyst-hydrocarbon interaction, especially when using a catalyst containing zeolite, is primarily a gas phase cracking process, such a catalytic reaction preferentially yields hydrocarbon products in the intermediate boiling range. In contrast, the reaction between liquid hydrocarbons and catalysts is primarily thermal decomposition, with gas and coke production being predominant. Thus, economically attractive intermediate (boiling) range hydrocarbons - pentane and higher molecular weight liquids - are produced. Also, the small droplets of the feed are more completely vaporized and catalytically converted,
A significant increase in the amount of "coke" formed on the spent catalyst due to the small amount of liquid remaining on the catalyst particles when separated from the overhead vapor after removal from the standpipe reactor. The yield of desired hydrocarbons is increased without any BACKGROUND OF THE INVENTION PRIOR ART Fluid catalytic cracking of heavy petroleum fractions is one of the major refining processes for converting crude oil or partially refined petroleum into useful products, such as fuel for internal combustion engines and heating oil. Fluid catalytic cracking (commonly known as "FCC") involves converting high molecular weight hydrocarbon liquids into finely divided solids at high temperatures in a standpipe or transfer line reactor. Contact with catalyst particles. The reactor is usually in the form of a standpipe, and the contact time of the materials is on the order of a few seconds, such as 1 to 10 seconds, and generally less than about 3 seconds. In order to optimize the production of gasoline and mid-boiling fractions, the contact time must be shortened in this way. By appropriate selection of temperature and recirculation time, the catalytic reaction is "quenched", minimizing the production of the economically undesirable end products methane and carbon of this type of reaction, and reducing the production of the desired products. The production of gasoline and mid-boiling point oil is highest.
During this short reaction time, a hydrocarbon feed, often in the form of vacuum gas oil, cycle oil, etc., with an initial temperature of about 149-427°C is sprayed onto the catalyst having a temperature of about 593-760°C. be done. As already mentioned, the present invention relates to a system for uniformly misting such a feed onto a thermal catalyst. Generally, the mixture is fluidized by steam and hydrocarbon gas resulting from a hydrocarbon feed that vaporizes on contact with a thermal catalyst. The reaction of the mixture is one with essentially instantaneous generation of large volumes of gaseous hydrocarbons. A mixture of hydrocarbon vapors and catalyst flows from the standpipe into a separation tank. In the separation tank, the used catalyst is separated primarily by gravity and inertia forces acting on the catalyst and returned to the regenerator through a stripper section in a downward direction. Fluidizing steam also generally flows upward through the falling catalyst and serves to strip hydrocarbon vapors from the spent catalyst. By flowing oxygen through the bed of spent catalyst in the regenerator, the coke consisting primarily of carbon on the spent catalyst is combusted to obtain heat for the process. The regenerated and heated catalyst is then recycled to the standpipe reactor. The desired product, hydrocarbon vapor, is recovered overhead. Typically, this recovery is accomplished using one or more cyclonic separators with the plenum chamber connected to a common pipe and plumbed directly to the distillation column. The vapor stream from the cyclonic separator extracts any residual or entrained catalyst fines. This catalyst fine powder is collected while passing through a dipleg connected to a stripper at the bottom or lower part of the separation tank and returned to the regenerator. A particular problem in the initial generation of hydrocarbon vapors may be that if the hydrocarbon liquid is injected into the reactor riser and does not come into direct contact with the catalyst, thermal cracking reactions will predominate over catalytic reactions. Such pyrolysis tends to produce end products consisting of methane and coke. That is, the hydrocarbons in the feed are completely converted to gas and coke rather than intermediate boiling hydrocarbon fractions. Further thermal decomposition occurs due to long-term contact between the unvaporized liquid hydrocarbon and the catalyst after it has been fed into the separation tank, and the final reaction mentioned above is particularly likely to occur at high rates. Further, since such catalytic cracking is originally a gas phase reaction, it is an essential condition that the hydrocarbon vapor comes into contact with the catalyst. It has been proposed in the past to use a nozzle for mist formation or fine liquid adaptation in a standpipe reactor, but
Generally, such fine dispersions are obtained by using water vapor or other vaporizing substances, in which case a two-phase fluid system is formed. A problem with such two-phase fluids is that the pressure drop as they pass through the spray nozzle is greater than with either fluid phase alone. Since the pressure drop across the nozzle when the nozzle dimensions and feed flow rate are constant has a significant effect on the size of the droplet formed by the nozzle,
This pressure drop is significant. It is of course also undesirable to add additional steam to the hydrocarbon feed. This added water vapor must be recovered in the overhead distillation column and generally creates "sour" water disposal problems. This is because oxides of sulfur, nitrogen and carbon in the recovered hydrocarbon vapors combine with water to form acids. Despite these problems, steam has been used until now because it lowers the partial pressure of the hydrocarbons and thus reduces the resistance to vaporization of the feed stream by the catalyst. be. U.S. Pat. No. 3,152,065 to Sharp et al.
No. 3,812,029 to Snyder, No. 3,654,140 to Griffel et al., and No. 3,071,540 to McMahon et al. 1 illustrates a feed nozzle for a fluidized catalytic cracking system that injects cocurrently with the feed. These patents disclose the advantage of using a steam "shroud" around a nozzle located directly within the standpipe reactor to atomize the hydrocarbon feed into the catalyst stream. . According to Schaap et al., the water vapor is swirled by helical vanes around a straight flow pipe for hydrocarbon liquids opening into the mixing chamber before discharging the mixture through an orifice to form a hydrocarbon feed. This is promoting the creation of mist. This nozzle is located within the catalyst stream. Sharp et al. also teach an alternative method of mixing and discharging a mixture by exchanging liquid and gas streams through concentric nozzles, with water vapor flowing through the center and liquid swirling around the water vapor. Snyder discloses that the hydrocarbon feed flows through surrounding water nozzles that co-currently cool the feed nozzle to prevent coking and to separate the water and feed. Disperse the mixture into fine droplets. Glitzfel et al. disclose utilizing a ventilate in the feed line that acts as a nozzle disposed within a standpipe reactor for the combined flow of steam and hydrocarbon feed. Alternatively, Snyder et al. discloses the use of a helical member within the hydrocarbon feed nozzle itself and the use of an ambient flow of water vapor to disperse the fluidized hydrocarbon feed into small droplets. In the arrangement disclosed by McMahon et al., steam and hydrocarbon liquid are fed cocurrently through the nozzle arrangement. This is similar to the device disclosed by Snyder in which water and hydrocarbon liquid are fed co-currently. A concentric nozzle is located at the center of the standpipe reactor, and an annular stream of catalyst particles surrounds the nozzle. Bartholic US Patent No.
No. 4,097,243 discloses a hydrocarbon feed distribution system in which a central nozzle and a plurality of peripheral diverging nozzles are fed by a diverging conical header. The feed distribution device or header is located in the center of the standpipe reactor with the catalyst stream surrounding the nozzle. U.S. Patent No. for Flyback
No. 3,848,811 discloses a fluid delivery nozzle for injecting a hydrocarbon feed into a standpipe reactor in a plurality of separate concentric streams. A plurality of circumferentially spaced holes extend outwardly relative to the direction of flow through the nozzle and act as a pair of frusto-conical members aligned exactly in the direction of flow. One of the frusto-conical members has an additional opening so that the feed is generally sprayed from a number of nozzles all outwardly and upwardly into the standpipe. The nozzle is located in the center of the standpipe reactor and comes into contact with the catalyst flowing down onto the nozzle, and the water vapor comes into contact with the catalyst around the nozzle as it flows upward. SUMMARY OF THE INVENTION As specifically distinguished from the nozzle for supplying hydrocarbon fluid to a standpipe described in the aforementioned patent specifications,
A particular object of the present invention is to reduce the substantial amount of the hydrocarbon feed through the nozzle without two-phase pressure drop, co-current passage through the nozzle with steam or water, or multiple flow paths. All hydrodynamic energy is used within a single flow path to ensure that the feed stream is dispersed into small mist-sized droplets. Such droplet liquid dimensions provide an almost instantaneous vaporization of the liquid hydrocarbon droplets by the hot catalyst particles in the standpipe, so that mainly middle distillate, That is, a gas phase catalytic reaction takes place in which a hydrocarbon liquid with a low boiling point is preferentially obtained. In accordance with the present invention, it has been discovered that a single feed stream can be misted by directing the liquid stream through deflection vanes into a single full flow centrifugal or helical acceleration chamber. At the end of the chamber is an orifice which feeds the liquid hydrocarbon directly into the catalyst stream in the standpipe reactor and which has a diameter substantially smaller than that of the chamber. are doing. Such a centrifugal chamber and orifice arrangement is particularly effective in dispersing the hydrocarbon feed into small mist-sized droplets. To further enhance the diffusion and spray angle of the misted particles into the catalyst, the area of the orifice opening is substantially equal to the opening area of the vane throat where the spiral flow is formed.
Both said openings have a substantially smaller area than the respective cross-sectional area of the feed flow line and the centrifugal or helical acceleration chamber supplying such liquid flow. A vane member that rotates the feed stream in a helical or centrifugal manner before ejecting it from a narrow-area orifice is placed at a shallow angle to the flow axis.
angle), thereby minimizing the pressure drop that occurs in the supply line and across the orifice. In a preferred form, the cylindrical or helical swirl chamber and outlet orifice are arranged in the axial direction of the hydrocarbon feed line, thereby minimizing the pressure drop of the fluid flowing through the nozzle. The orifice exit throat should be substantially shorter than the length of the centrifugal swirl chamber.
By doing so, substantially all of the hydrodynamic energy in the flowing fluid is converted into dispersion or misting of small droplets. The large opening area through the swivel vanes and exit orifice is also advantageous over prior art nozzle designs. This is because the larger area reduces nozzle blockage problems, especially for nozzles recessed into the walls of standpipe reactors, and avoids abrasion and direct heating of the hot catalyst flowing above it. This is because the mist or dispersed flow pattern of the feed delivered from the orifice is not disturbed. In a preferred form of the invention,
A plurality of nozzles are distributed at equal intervals around the transition section of the standpipe reactor where the catalyst stream changes to a mixture of catalyst and hydrocarbon material. Objects and advantages of the present invention other than those stated above include:
It will become clear from the following detailed description with reference to the drawings, which form an integral part of the present specification. Preferred Embodiments of the Invention The drawings, particularly FIG. 1, show a fluid catalytic cracking apparatus to which the present invention is applied. The system generally consists of a standpipe reactor 10 in which heated catalyst supplied from a regenerator 12 is reacted with liquid hydrocarbons. The catalyst flows from regenerator 12 through U-tube 14 to standpipe reactor 10 . The catalyst is partially fluidized within the U-tube 14 by gas, preferably steam, supplied by a series of nozzle rings 13 along the length of the U-tube. The catalyst fed by gravity from the intake port 15 in the regenerator 12 is entrained by water vapor and partially fluidized, and is then transferred to the standpipe reactor 10.
transported to. A flow of hydrocarbon liquid is supplied to standpipe reactor 10 by line 21 under control by valve 22 . As shown in FIG. 2, line 21 leads to a ring of supply nozzles 20 connected to an annular header 23. As shown in FIG. Catalyst particle diameter is 20~120μ
Because of the degree of It is important to have a droplet size that is accurate. The above conditions are essential since the gas phase contact reaction time to produce the desired low boiling range liquid by contact between the thermal catalyst particles and the hydrocarbon droplets is on the order of 1 to 10 seconds. . Reaction times of 1 to 3 seconds, and often about 1 second, are often adequate for droplet contact reactions that produce intermediate boiling hydrocarbons rather than gas or coke. The virtually instantaneous reaction of the small misted hydrocarbon droplets with the heated catalyst particles generates a large volume of hydrocarbon vapor that first fluidizes the mixture into a standpipe. It is carried upward toward the type reactor 10 and immediately discharged and separated in the separation tank 24. The reacted hydrocarbon and catalyst are disclosed in Co-pending U.S. Patent Application No. 238,380 (Feb. 26, 1981);
No. (dated December 29, 1982) and No. 363946 (dated December 29, 1982)
(dated March 31, 2013) in the upper part of tank 24 by the method described in each specification. The general structure and arrangement of a suitable fluid catalytic cracking system to which the present invention may be applied, and in particular the misting feed nozzle that is the subject matter of the present invention, are disclosed herein. It should be referred to as part of the As described in the foregoing specifications, the catalyst is discharged or discharged from the standpipe reactor 10 and separated from the steam by the effects of inertia and gravity.
The spent catalyst is collected in a strip section 32 attached to or in the lower part of the vessel 24. The generated vapor is collected at the top and condensed in a distillation column (not shown). The catalyst recovered in the separation process contains a certain amount of residual hydrocarbons deposited on the spent catalyst in the form of coke, which is carbon in nature. The spent catalyst containing such carbon or coke is returned to the regenerator 12 via the stripper element 32. Removal of residual hydrocarbon vapors from the spent catalyst is carried out in line 34.
This is done within the stripper 32 by supplying water vapor from the lower end of the stripper 32 through a supply nozzle. Stripper 32 typically includes a plurality of baffles or channels (not shown) to increase the residence time of the spent catalyst. Steam is introduced through a series of nozzle tubes 36 along the return U-tube 38 to aid in the passage of the catalyst back to the regenerator 12. Regeneration of the spent catalyst is accomplished by adding oxygen through line 40 to combust and oxidize the spent catalyst supported on grid 42. This imparts heat to the catalyst circulating in the system, and the heated catalyst is transferred to the intake port 5.
from bed 47 back to standpipe reactor 10 through.
The resulting off-gas from burning the coke exits the regenerator 12 through a cyclone and flue pipe (not shown). As previously mentioned, the present invention is directed to vaporizing the liquid hydrocarbon feed in the standpipe reactor 10 as quickly as possible so that the reaction mixture is
Relating to a method of proceeding with the essential reaction between the vaporized gas phase hydrocarbons and the catalyst during passage through the standpipe reactor 10 within an allotted time of 10 seconds, most preferably 1 to 3 seconds. It is. With such short reaction times, it is essential that all of the liquid feed be converted to gas virtually instantaneously to achieve the necessary catalyst-gas phase reaction.
Such reactions decompose heavy hydrocarbon molecules into intermediate-boiling hydrocarbons. To achieve such rapid gasification, the flow pattern of the liquid feed into the fluidized catalyst stream must be such that the droplet size and distribution are consistent at the flow rate and pressure at the appropriate application scale. Must be uniform. Also, nozzles that create flows with such patterns can become clogged (due to coke formation from hot hydrocarbons flowing through the nozzle),
It must be able to be used for long periods of time without mechanical wear (due to the abrasive action of the fluidized catalyst particles). Although it has previously been proposed to use steam or water as the primary dispersant fluid to atomize hydrocarbon feed streams, in accordance with the present invention, steam is added. We have found that excellent results can be obtained even without it. In the present invention, a nozzle with a single swirling chamber is used. The chamber is located between a full-flow liquid supply line and a reduced area orifice formed at the outlet end of the swirl chamber to act as a helical or centrifugal acceleration compartment. For this purpose, the third
As shown, the diameter of the swirl chamber 51 is substantially the same as the full inner diameter of the flow nozzle 20.
The nozzle 20 does not protrude into the flow path of the standpipe reactor 10 in the transition section 17 but is connected to the wall 11 and the insulation-abrasion layer 1.
It is desirable that it is recessed by the thickness of 9. As can be seen, this allows the liquid flow through the orifice 54 to remain undispersed and at full flow until a dispersion pattern within the catalyst flow path in the transition section 17 is established. The pitch of the vanes 53 and the chamber 5 relative to the diameter and depth or length of the orifice 54
The dimensions and length of 1 are selected such that the angle of dispersion from the nozzle 20 is adjusted so that the dispersion pattern produces appropriately sized droplets and dispersion occurs at some distance from the orifice. With this method,
The nozzle, including the orifice end, is recessed into the side wall of the reactor standpipe so that the small droplets do not come into contact with the side wall of the standpipe reactor 10, so that the catalyst flowing through the standpipe reactor 10 come into contact with. It is also important to utilize substantially all of the hydrodynamic energy from the hydrocarbon feed through the nozzle 20 to impart a swirling or centrifugal effect to the feed. By doing so, a straight cylindrical flow with substantially the same diameter as the orifice is established for a short distance, such as 1.27-5 cm, and then a wide-angle cone of small droplets is formed, as shown schematically in Figure 3. The desired pattern is that the spray has a complete distribution of said flow. In order to obtain such a flow pattern, a pair of deflection vanes 53 are disposed at an angle and intersecting the axis of the flow from the nozzle 20, as shown in FIGS. 3 and 4. Vanes 53, which cause the flowing liquid to rotate or spiral, create such a pattern.
These vanes connect the supply line and the chamber 51
It has a pitch of 15° to 45° with respect to the axis of Preferably, the pitch angle is between 25° and 35°, most preferably about 30°. This angle of the vanes 53 allows the sum of the two flow areas to be substantially equal to the flow area of the exit orifice 54. This allows the full pressure of the supply line to be applied to the rotation of the flow within the chamber 51, and then the liquid can be discharged in the desired pattern. As shown, the swirl or centrifugal action is transverse to the flow direction and circular, resulting in a complete rotation by the entire flow through the nozzle before exiting the narrowed throat of the orifice 54. . Although the orifice 54 is shown as a single circular or cylindrical opening, the opening may have a variety of other shapes, such as the cylindrical surface 55 of the end wall 56.
It may be a sawtooth notch inside. As shown, the length of surface 55 need only be sufficient to form a solid flow over a short distance from orifice 54. Such a distance allows the nozzle to be recessed into the sidewall of the standpipe reactor 10, including the corrosion-resistant coating, without any interference with the formation of a wide-angle conical dispersion pattern. In practice, the angle A at the tip of such a conical or parabolic region should exceed 90°, preferably the third
As shown in the figure, it is approximately 120°. As shown in FIG. 2, the nozzles 20 can be distributed at equal intervals around the circumference of the standpipe reactor 10. The number of nozzles varies depending on the diameter of the standpipe and the flow rate of the catalyst through it, but can range from one or two to many, for example six as shown in Figure 2, or twelve.
The number may be greater than ~15. As shown in the figure, the angle of the nozzle axis is between 20° and 70° with respect to the standpipe reactor axis, and more preferably between 30° and 50°, thereby controlling the flow of the catalyst-hydrocarbon mixture. Make it easier to disperse liquid particles in the direction. In the present invention, although the entire feed is intended to be a hydrocarbon liquid, the feed liquid is Direct addition of water vapor is also contemplated. however,
It is essential that such a water vapor and hydrocarbon mixture is allowed to settle before the fluid is introduced into the nozzle 20 and that the mixture is rotated together within the chamber 51 and discharged from the orifice 54. By doing so, the pressure drop during passage through the nozzle is minimized so that the mixture does not significantly reduce its full flow under the highest effective hydrodynamic pressure and after the flow from orifice 54 has dispersed. , can be turned into small droplets with the desired particle size. In this way, the desired mist is formed in the standpipe, so that such droplets that come into contact with the heated catalyst particles are immediately and completely vaporized. As previously mentioned, the use of steam for the initial reaction of the hydrocarbon fluid with the catalyst is generally undesirable in fluid catalytic cracking. This is because, along with the steam recovered in tank 24, water vapor must pass through the top of the column and be treated with the condensed hydrocarbon products. Such condensation creates "sour" water treatment problems, but
This is because the water-soluble substances of the condensate, especially oxides of sulfur, nitrogen and carbon, lead to problems in disposing of acidic water. Additionally, the need to recover and dispose of the "sour water" in the condensate directly reduces the efficiency of the conversion process and increases the operating costs of the system. In the present invention, 538-760°C, preferably about
It is contemplated that the catalyst particles will be heated to a temperature of 649-704°C. Although the system of the present invention produces almost instantaneous mist and vaporization at higher temperatures, such as up to 1500°C, there are still no commercial contact field systems capable of operating at such high temperatures. Not common. Nevertheless, the present invention is particularly suited for such high temperature operations because the full flow of hydrocarbon fluid that would normally be subjected to coking conditions is protected within the nozzle. be. In order to keep the flow rate through the nozzle high, coking should be particularly avoided in this way. Therefore, the conventional workaround for coking by using a shroud of steam in the ambient atmosphere, or vice versa, is to reduce the hydrocarbon feed to small droplets in the form of a mist. This is solved by the nozzle operation of the present invention which disperses Typical catalysts in new types of fluid catalytic cracking processes consist of a combination of crystalline and amorphous materials, such as molecular sieves. The main components of this type of decomposable catalyst are silica and alumina.
Contains alumina in a weight ratio of 10-60%.
Rare earth elements in various combinations can also be included. Silica-magnesia and other mixed oxide catalysts can also be used. The catalyst used is
It may include particles having a wide range of free settling velocities. Commercially available catalyst powder for cracking is 60-90% by weight in the range of 20-120μ.
It has a particle size distribution of A particular advantage of fluid catalytic cracking is that a wide variety of hydrocarbon feedstocks can be purified in this type of process. These raw materials include straight-run petroleum distillates,
Included are petroleum kettle residues, deasphalted oils, hydrocarbon oils and mixtures thereof. Other petroleum hydrocarbon fractions, ie, those with boiling points of 316° C. and above, can be advantageously converted to lower boiling point, more valuable hydrocarbon products. In such reactions, the feedstock temperature is generally from ambient to 175°C or 205°C. Although it is possible to vaporize the feed before discharging it into the stream of regenerated hot catalyst particles flowing through the standpipe reactor, it is economically advantageous to bring the hydrocarbons into contact with the hot catalyst. It is preferable to vaporize mainly by Although a wide range of catalyst to oil feed weight ratios may be used, catalyst to oil feed weight ratios ranging from about 2:1 to about
20:1 and hydrocarbon-catalyst contact time from 1 to about 10
A contact time of 1 to 3 seconds is preferred, and a contact time of 1 to 3 seconds is most preferred. Reasons why the arrangement of a cylindrical swirling chamber and an orifice having a smaller diameter and shorter throat than the chamber is so effective in vaporizing the feed in the desired pattern. cannot be completely understood. However, the misting action by the nozzle has a low degree of pressure drop, and while passing through the passage of the rotary vane, which has a flow area approximately equal to the area of the orifice,
It is envisaged that this is achieved by changing the fluid from axial flow to annular or centrifugal flow. Thus, the entire spray delivered from the swirling chamber through a relatively short orifice rapidly forms a short cylindrical flow section, known in hydraulics as a vena contracta, which spreads out into a large conical section. be. This pattern is not only effective for the catalyst to rapidly convert the feed from suitably sized small droplets to gas, but most importantly, it allows the nozzle to be recessed into the sidewall of the standpipe. This also makes it possible to prevent catalyst wear and direct heating of the nozzle by the hot catalyst.
As the feed rapidly expands into finely divided particles in a wide-angle conical pattern, contact between the hot droplets and the hot catalyst results in highly turbulent flow due to the production of large amounts of hydrocarbon vapor. A gas flow occurs. The flow from the nozzle orifice joins into the catalyst stream at a point where the area becomes large due to the transition from the U-shaped pipe 14 to the standpipe reactor 10, and the flow of the catalyst becomes somewhat slow. is desirable. The transition section 17 provides a region of increased cross-sectional area to aid in rapid acceleration of the feed-catalyst mixture by the steam generated from the reaction of the hydrocarbon with the high-temperature catalyst. It is not completely understood why the desired hydrocarbon expands so rapidly and more completely as a gas. However, there are commercial fluid catalytic cracking systems that use conventional nozzles that are not engineered to obtain a misted spray, and fluid catalytic cracking systems that use nozzles for vaporizing the feed according to the present invention. The comparison is particularly moving. Such changes in the yield of hydrocarbon fluids obtained from the improved hydrocracking system are shown in the following table.

Table: By using the nozzle according to the invention, hydrocarbons with a carbon number _of 4 or less, such as butane, propane or ethane, are significantly reduced while It will be clear from Table 1 that the hydrocarbons increase substantially. It is also heavier and has a boiling point of 343, indicating an increase in coke or coking of the catalyst.
It can be seen that the amount of hydrocarbons produced at ℃+ is also decreasing. Based on the above comparison and assuming full operation of a commercial plant, the increase in value of the desired product obtained using the nozzle arrangement according to the invention is:
Valued at a rate of 25 cents per ^gallon , this yields a profit of $2500 per day. For one year, the net gain in value of the product is 750,000
~$900,000/year. Although only a few aspects of the invention have been described,
It will be apparent to those skilled in the art that various changes and modifications can be made to the present invention based on the principles of operation and structure disclosed above without departing from the spirit of the invention. All such changes and modifications that fall within the scope of the following claims are intended to be included within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a front view of the lower part of a fluid catalytic cracking system to which the feed nozzle system of the present invention is applied, in which a standpipe reactor to which heated catalyst is supplied from a regenerator and a used catalyst are separated. A return line flowing from the tank back to the regenerator is schematically shown. FIG. 2 is a cross-sectional view in the direction of arrows 2--2 of FIG. 1, showing the arrangement of a plurality of supply nozzles constructed in accordance with the present invention. Such a mechanism directs the hydrocarbon feed from a circular header to a plurality of misting nozzles distributed around the standpipe reactor. FIG. 3 is a cross-sectional view of one of the nozzles shown in FIG. 2 in the direction of arrows 3-3. This nozzle is constructed in accordance with the present invention to ensure that a full flow of hydrocarbons is delivered as a mist into the standpipe reactor from within the sidewall of the fluidized catalyst stream line. FIG. 4 is a sectional view taken in the direction of arrows 4 to 4 in FIG. 3, particularly showing the blade member. These vane members, when the hydrocarbon feed enters,
The feed stream is subjected to centrifugal or helical motion and is directed directly to the catalyst through a reduced diameter orifice at the tip of the nozzle. In the figure, 10... Standpipe reactor, 12... Catalyst regeneration device, 13 and 36... Nozzle ring, 14 and 38... U-shaped tube, 15... Regenerated catalyst intake port, 17
...Transition part, 20...Raw material supply nozzle, 23...
... Header, 24 ... Separation tank, 32 ... Stripper, 51 ... Rotating (centrifugal) chamber, 53 ...
...Blade member, 54...Orifice.

Claims (1)

[Scope of Claims] 1. A fluid catalytic hydrocarbon cracking process in which a heated catalyst is circulated in a standpipe reactor and contacted with a liquid hydrocarbon feed that may or may not contain water or steam; introducing said liquid feed into the standpipe reactor into contact with the heated catalyst flowing therein by imparting centrifugal rotation about the axis of the liquid feed flow ( provided that the centrifugal rotation is imparted by a flow of liquid through a cylindrical chamber provided in at least one conduit feeding the standpipe reactor) and then the standpipe reactor. directing said stream through an orifice located in an opening in a side wall of the reactor, provided that said orifice has a diameter less than the diameter of said chamber and a throat substantially shorter than the length of said chamber; so that the hydrodynamic pressure of the feed flowing through the feed line converts the feed into a cylindrical stream exiting from an orifice in an opening in the reactor sidewall, and then A process for fluid catalytic hydrocarbon cracking, characterized in that, in a tubular reactor, a uniform mist of droplets is dispersed over a uniform conical volume and brought into contact with the heated catalyst particles. 2. The liquid feed is fed from a plurality of uniformly distributed locations around the transition between the catalyst stream and the hydrocarbon-catalyst mixture stream in the standpipe reactor. The fluid catalytic hydrocarbon cracking method according to claim 1. 3. A fluid catalytic hydrocarbon cracking process in which a heated catalyst is circulated in a standpipe reactor and contacted with a liquid hydrocarbon feed, with or without water or steam, in a uniform spray of liquid particles. contacting the hydrocarbon feed with a stream of heated catalyst particles for hydrocarbon cracking, with a centrifugal acceleration chamber between the hydrocarbon fluid feed line and the flow path of the standpipe reactor in the processing system; creating the liquid droplets by positioning a nozzle having a chamber coaxial with the conduit constituting the supply line and formed within the end wall of the chamber and having a smaller diameter than the chamber; an outlet orifice disposed within a sidewall of the reactor standpipe, and a flow path of the orifice having an area substantially less than an area of the chamber; includes at least one pair of vanes between the hydrocarbon supply line and the centrifugal chamber, the total area of the flow path to the vanes being substantially equal to the area of the orifice, such that the fluid feed is in the low boiling range due to its dispersion pattern into a wide-angle conical volume for contact with the heated catalyst as a mist of particles, characterized by being delivered as a solid stream flow through the sidewall. A method as described above, wherein the production of hydrocarbon fluid is high, while the conversion of the hydrocarbon fluid to gas and coke is reduced. 4. In a fluid catalytic hydrocarbon cracking apparatus in which a heated catalyst is circulated in a standpipe reactor and contacted with a liquid hydrocarbon feed with or without water or steam; at least one nozzle arrangement for atomizing a feed of liquid hydrocarbon into the reactor, the nozzle arrangement being recessed within the wall of the standpipe reactor, and the nozzle arrangement being recessed into a wall of the standpipe reactor; The flow axis of said orifice and chamber is controlled by having a swirling chamber between a liquid hydrocarbon supply conduit and an exit orifice from said chamber and having a fixed vane member between said supply line and said chamber. centrifugal rotation is imparted to said liquid, said outlet orifice having a smaller diameter and substantially shorter length than said swirling chamber, and said orifice and said chamber both having a A device as described above, characterized in that it is open to full flow throughout the entire cylindrical volume. 5. The apparatus of claim 4, wherein the plurality of nozzles are distributed substantially uniformly around the transition section of the reactor. 6. Apparatus according to claim 4, wherein said nozzle is arranged at an angle of 20° to 70° with respect to the axis of said standpipe reactor. 7. The device of claim 4, wherein the fixed vane has an angle of 15° to 45° with respect to the axis of the chamber. 8. The device of claim 7, wherein said angle is between 25° and 35°. 9. The apparatus of claim 7, wherein said angle is between 15° and about 30°.