JPS585392A - Fluidized catalytic cracking process of hydrocarbon supplying raw material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for fluid catalytic cracking of a hydrocarbon feedstock in a reactor system that includes an interconnected cracking zone and a regeneration zone.

Fluid catalytic cracking has long been considered one of the major gasoline production methods in the refining industry. Typically, the feedstock used is a distillate, such as gas oil, and the operating conditions are such that the gas oil feedstock has a relatively high conversion rate to allow maximum yield of gasoline. has been selected against. The cracking of gas oil to gasoline is well understood and the limits placed on the feedstock gas oil are well defined. The main limitations currently placed on gas oil feedstocks are the amount of carbon or "coke" precursors and the amount of metal compounds included in the feedstock.

These coke formers or precursors, which are typically high molecular weight linear annular hydrocarbons, are primarily a function of the crude feed type and boiling range of the material.

Results obtained by Conradson or Ramsbottom carbon residue analysis indicate the approximate extent of the coking tendency of these compounds and feedstocks. Typically, the amount of these compounds in the gas oil feedstock is determined by the Conradson method.
It is desirable to limit it to % by weight or less.

The reason is that if the coke precursor compounds in the gas oil are allowed to increase, more coke can deposit on the catalyst in the hydrocarbon reaction zone than is required for the heat balance of the process. Because it will be. The temperature in the regeneration zone at which the coke is oxidized to CO and/or still CO2 is
The temperature may rise too high and the catalyst particle temperature may rise to such a temperature that the catalyst structure is damaged or destroyed resulting in loss of activity.

The second major limitation imposed on gas oil is the presence of organic nickel (Ni)-containing compounds, organic vanadium (V) in gas oil.
This is the content of contained compounds and organic iron (Fe) containing compounds. These compounds, commonly called "porphyrins", distill out in the high boiling fraction of vacuum gas oil. Additionally, inorganic metal compounds may also be present. Typically, the metal content is expressed in ppm by weight as defined by the formula NE=Ni+0,3XV2, where the Kel weight is 0. Should be limited to less than ≠. The circulating catalyst absorbs the metals almost completely and its performance decreases. These metals in an active state on the catalyst can reduce the yield of the main gasoline product, promote various dehydrogenation reactions, and produce large amounts of hydrogen and coke. This leads to a large increase in the volume of unwanted gas, leading to rapid overloading of the gas compressor and gas recovery equipment.

Residual oil such as whole crude oil
'? or atmosphere crude oil
In addition to being difficult if not impossible to completely vaporize, the residual oil also contains higher amounts of "coke" precursors (residues) than typical gas oils. (measured by Conradson or Ramsbottom carbon residues) and large amounts of metallic Ni,
It is clear that it contains V and Fe. Despite the potential processing difficulties posed by the presence of such contaminants, refiners are encouraged by the frugality of crude oil supplies to move beyond the relatively clean nature of distillates such as gas oil. ,
Attempts have been made to expand the nature of the feedstock charged to fluid catalytic cracking processes. To increase feedstock availability to meet gasoline and fuel oil demands, high boiling point feedstocks, previously considered minimal or unsuitable due to such contaminants, are increasingly being considered. It is becoming more and more common.

The reaction conditions for fluid catalytic cracking are typically in the temperature range l
1-50°C, pressure range from atmospheric to absolute par, catalyst to oil ratio less than 7. The catalyst-to-oil ratio is the quotient of the catalyst circulation rate and the hydrocarbon oil feed rate (expressed in the same mass units).

In a fluid catalytic cracking unit, heat must be removed at a controllable rate from the regeneration zone where the carbon deposits are burned and the spent catalyst is regenerated by an oxygen-containing gas such as air to maintain equilibrium cracking conditions. Yes: because the regeneration heat added to the catalyst is transferred to the fresh oil feed to the cracking reactor. Still, continuous heat removal is necessary to prevent excessive regeneration temperature levels that tend to sinter and deactivate the catalyst due to surface area reduction.

Heavy hydrocarbon feedstocks, such as atmospheric residue (atmo
spheri-c residues), vacuum residues (
During the catalytic cracking of vacuum residues, and heavy crude oils, more carbon is deposited on the catalyst particles than in the case of cracking feedstocks such as gas oil. The problem of heat removal becomes even worse when the spent catalyst from catalytic cracking of such heavy hydrocarbon feeds is regenerated by combustion with oxygen-containing gas in a regeneration zone: since in this way This is because more heat than is used is released in the regenerator.

By introducing a more active zeolite-based cracking catalyst,
The above-mentioned problems regarding the heat balance, especially at maximum yield conditions, are becoming more critical: since maximum product yields are now achieved with low coke formation and the heat balance is This is because they are being disturbed again. To avoid excessive cracking of the feedstock, it is necessary to reduce the severity of cracking when using more selective and active zeolite-based cracking catalysts. The severity of decomposition is usually determined using the "severity parameter".
C10
is commonly referred to as the catalyst-to-oil ratio. All rates are given in mass units, usually tons/day. Reducing intensity can be accomplished in several ways. One way to reduce the severity of decomposition is to reduce the catalyst circulation rate C. However, this results in an increase in the temperature of the catalyst in the regeneration zone: since the reduced amount of catalyst provides the necessary heat for the endothermic cracking reaction, the same amount of coke in the exothermic regeneration reaction The amount released is σ
This is because they must absorb the same amount of heat. As already acknowledged, excessive regenerator temperatures can spoil the catalyst and even damage the regenerator itself due to the resulting high catalyst particle temperatures. Therefore, further reduction in the severity of decomposition will be inhibited by maximizing the regeneration temperature.

On the other hand, increasing the oil feed rate O is carried out by direct contact with the regenerated high-temperature catalyst and also by mixing the feedstock, which usually takes place in a so-called lift pot and a so-called riser zone. This will cause problems regarding vaporization. Since the high temperature regenerated catalyst coming from the regeneration zone is used to provide the necessary heat for the feedstock vaporization reservoir, lowering the catalyst-to-oil ratio typically reduces the temperature of the regeneration zone and the vaporization of the feedstock. may have an adverse effect on Particularly with the heavy hydrocarbon feedstocks mentioned above, this poses a problem as insufficient vaporization of the feedstock leads to increased coke formation in the cracking zone. Although some coke production is required in fluid catalytic cracking processes due to the desired heat in the feed vaporization reservoir, excessive coke production results in catalyst temperatures that are too high during regeneration.

Another possible way to reduce the severity of decomposition is, for example, by reducing the amount of reactor catalyst remaining.
By decreasing t 1nventory ),
The goal is to increase the space velocity Sv (ie, oil feed rate/reactor catalyst residual amount). However, this presents the same problems discussed above with respect to reducing the catalyst to oil ratio. In addition, the reactor take-off chamber
There is a limit to lowering the catalyst residual level due to the need to maintain an upper level of the fluidized bed above the w-off (5 tandpipe).

In catalytic cracking reactor systems, it is naturally desirable to regenerate the catalyst particles as completely as possible and to utilize all of the heat released by completely burning off the coke deposits. However, in practice 'combustion is often incomplete: the carbon burns to carbon monoxide in the regeneration zone. The carbon oxide is then oxidized to carbon dioxide in a separate flue gas combustor combined with a waste heat daisy to recover the chemicals and sensible heat present in the flue gas. The reason for this complex mechanism is that complete combustion in the direct regeneration zone releases a large amount of heat and
This is because it will damage the catalyst and/or the regenerator material. While performing so-called "complete CO-combustion",
If it were possible to keep the temperature of the regeneration zone below 723°C, which is the upper limit normally accepted, this would represent a great simplification of the catalytic cracking process. Unfortunately,
Most of the heavier feedstocks currently in use are
Complete CO combustion is not possible with these feedstocks as it creates too many coke deposits on the catalyst.

From the foregoing, it can be seen that the operation of a heat-balanced fluid catalytic cracking unit is constrained by several interacting operating conditions and that little flexibility remains for changing the feedstock and/or catalyst. It is clear that this has not been done. It is desirable to operate the process to produce an optimum amount of middle distillate or an optimum amount of gasoline according to market demands, so the maximum regenerator temperature, the minimum regenerator temperature, the capacity of the equipment used, the catalyst There is a clear need for an improved fluid catalytic cracking process that does not restrict operational flexibility due to the total heat balance requirements of the process as determined by parameters such as activity of the feedstock, coking tendency of the feedstock, etc.

It is therefore intended to provide a method for fluid catalytic cracking of hydrocarbon oils, and more particularly for treating more difficult to crack and/or more coking feedstocks. Such feedstocks include "residues" (r
residual oils, which include heavy residual oils such as tar, asphalt (bitumen), asphaltones, resin fractions, etc.
The residual oil may be a whole crude oil, an atmospheric prefixed crude oil, or even a residual oil fraction (having a boiling point higher than about 370°C to 00°C that remains after vacuum column distillation). However, more unusual feedstocks are also included, such as propane and butane deasphalted oils, extractives and pyrolyzed and flashed distillates. Usually, the average carbon residue (petroleum product test) is the Conradone carbon residue (the Co
nradson Carbon Re5ide of
Petroleurn Product test,
ASTM designation D/g 9
Feedstocks and/or feedstock mixtures having a nickel equivalent (as defined above)/≠ppm of less than 2% by weight (determined by A 3 )) can be treated according to the method according to the invention. It is intended to process a wide range of feedstocks, and the use of a wide range of catalysts is also contemplated. Conventional cracking catalysts may be used, such as natural or synthetic clay-based, polymer or silica-alumina-based amorphous catalysts, but usually crystalline catalysts complexed with siliceous matrices such as silica-alumina, silica gel, etc. The use of preferably more active and/or more selective cracking catalysts comprising polyaluminosilicates or iron silicate zeolades is contemplated. The process of the invention is therefore characterized by a very wide variation in feedstock, catalyst and product, with the result that the activity/selectivity of a particular catalyst composition is conveniently expressed by its zeolite content.

The zeolite content is determined, for example, by French Patent Specification No. 1! ,
It may be conveniently determined as described in No. 330.7j6. The zeolite-containing catalyst preferably comprises:
Zeolites, especially natural or synthetic alkali metal aluminosilicate zeolites, such as type It contains 7 to 20% of The zeolite content is preferably between / and 10% by weight, based on the total catalyst composition, since application of too much zeolite leads to excessive decomposition, ie excessive gas formation.

Therefore, the object of the present invention is a method for fluid catalytic cracking of hydrocarbon feedstocks, in particular heavy residue hydrocarbon feedstocks, in which the heat balance of the reactor system, as defined below, The object of the present invention is to provide a method that does not rely exclusively on heat transfer by.

A further object is to provide a method which makes it possible to obtain optimal yields of gasoline or middle distillates, depending on market demand, from heavy hydrocarbon feedstocks, in particular by applying catalysts based on zeolites. The goal is to provide the following.

Yet another object is to provide a fluid catalytic cracking process that can be operated with complete c'o combustion when regenerating spent coke-containing catalysts.

The general object of the present invention is to increase the operational flexibility of the process, regardless of the type of feedstock being treated or the type of catalyst used.

These objectives are achieved by removing heat from the bed of regenerated catalyst by indirect heat exchange with the fresh hydrocarbon feedstock to be processed to maintain the regeneration zone temperature below 723'C. achieved according to.

Accordingly, the present invention provides a method for fluid catalytic cracking of a hydrocarbon feedstock in a reactor system including at least a cracking zone and a regeneration zone in communication with each other, the hydrocarbon feedstock being exposed to a high temperature cracking catalyst in the cracking zone. so that at least a portion of the feedstock is vaporized under cracking conditions in the temperature range ≠2j°C to 0°C, the pressure range atmospheric pressure to ≠bar absolute, and a catalyst-to-oil ratio of less than 7 and subsequently The spent catalyst containing coke deposits is decomposed into boiling hydrocarbon products and the low boiling hydrocarbon products are then separated and recovered from the spent catalyst while the oxygen-containing gas is passed through the catalyst bed. The coke deposits are passed through a regeneration zone where the coke deposits are oxidized with the production of heat, the catalyst is recovered and heated, and the hot regenerated catalyst is then returned to the cracking zone. In a process for fluid catalytic cracking of a hydrogen feedstock, the temperature of the regeneration zone is increased by removing heat from a bed of catalyst that is being regenerated by indirect heat exchange with fresh hydrocarbon feedstock. ; the feedstock is then heated to a temperature of at least 200°C, after which the feedstock is introduced into a cracking zone and in direct contact with the hot regenerated catalyst and vaporized at a temperature above 200°C. The present invention relates to a method for fluid catalytic cracking of the hydrocarbon feedstock, characterized in that the hydrocarbon feedstock is subjected to fluid catalytic cracking.

The main advantage of the process according to the invention is that the heat balance is no longer dependent on the catalyst circulation and only on the heat transfer from the regeneration zone to the cracking zone.
It is about becoming independent. The possibility of extracting heat from the circulating catalyst by preheating the feedstock in the regeneration zone has been proposed, which is then fed to the endothermic cracking reaction. Thus, the method of the present invention allows greater flexibility in decomposition severity without exceeding regeneration zone temperature limitations. Vaporization by contacting the preheated feedstock with the hot catalyst occurs substantially quickly, thus minimizing the amount of liquid hydrocarbons in the pores of the catalyst. Liquid hydrocarbons remaining in the pores of the catalyst are a major source of excessive coke deposits when using heavy feedstocks.

It is known per se to extract the heat generated during catalyst regeneration: for example by indirect heat exchange in the bed of the catalyst with water or steam fed to coils, for example several interconnected tubes, and high-pressure steam. It is known to generate 1~
However, in such devices heat is irreversibly extracted from the reactor system. In the present invention, such heat generated is used in the reactor system by reheating the feedstock to be processed in the same system.

The components of the cracking process according to the invention are typically comprised of lower molecular weight, lower boiling point compounds than those found in the initial feedstock. These products have particular use as feedstreams for the production of petrochemicals, polymers, gasoline and alkylates. The cracking method uses middle distillates, i.e. kerosene and gas oil (approximate boiling range of each / lO~3
00°C and 7gθ to 370°C) and for maximum production of gasoline and naphtha in the boiling range of about 30-200°C, but some gaseous compounds such as lower olefins always occurs.

It is possible to perform indirect heat exchange between the beds of regenerated catalyst with fresh hydrocarbon feed in several ways. For example, it is possible to circulate the heat exchange fluid through heat exchange tubes located in the regeneration zone and then through a heat exchanger into which the feedstock is also directed.

However, this solution requires considerable investment and is usually not preferred. Typically, indirect heat exchange of the regenerated catalyst with fresh hydrocarbon feedstock is accomplished by passing the feed through seven or more heat exchange tubes located in a bed of catalyst to be regenerated. will be carried out.

The presence of tubes in the fluidized bed (occupying about 20% of the floor area)
Surprisingly, it has been found that the air bubbles in the bed have a further positive influence on the size of the bubbles and the distribution of the bubbles. The horizontal tube breaks up the bubble growth by breaking up the rising bubbles into a large number of smaller bubbles, which leads to an increase in the mass transfer coefficient from the air to the catalyst particles: i.e. more coke. can be burned with the same throughput of air.

The dimensions and thickness of such tubes, as well as the type of material to be used, will be apparent to those skilled in the art of designing heat exchange equipment for oil processing industry reservoirs.

While during normal operation, the average temperature of the feedstock rises to temperatures above 200°C, rate regulation of the feedstock in the heat exchange tubes and heat transfer within the hydrocarbon feedstock may cause the feedstock temperature to rise anywhere I found out that it prevents it from going too high. The maximum film temperature at the inner tube surface, about ≠ 00 °C, still occurs, but such a temperature does not slow down the appreciable thermal decomposition of the hydrocarbons: because the heat is immediately transferred to the bulk oil. This is because the temperature will drop as a result.

The initial temperature of the feedstock to be treated in the catalytic cracking unit, ie before preheating according to the invention, depends on its source and the degree of cooling it undergoes during its production. In refineries it is normal practice to minimize heat losses and therefore the cracked feedstock, for example the residue of an atmospheric distillation unit or a vacuum reduction unit, is preferably passed through an insulated line as soon as it is obtained. transported to the fluid contact unit. The (initial) feedstock temperature is then around 200°C or 250°C. The same applies to other feedstocks such as gas oil, deasphalted oil, etc.

Sometimes a charge preheater (char
ge-preheaters) would have to be used: for example, the initial temperature of the feedstock may be so low that even when preheated according to the invention the feedstock will be vaporized by direct contact with the hot fresh regenerated catalyst. This is when the temperature is not reached. On the other hand, sometimes a charno cooler will have to be used: for example when the feedstock is difficult to decompose and produces a high degree of nicoke, which leads to too high a temperature of the catalyst particles. Preheating the charge material is expensive, and precooling the charge material, apart from being labor intensive, reduces vaporization of the feed material on contact with the hot catalyst. As mentioned above, poor vaporization results in increased coke formation and reduced product yield. Therefore, hydrocarbon feedstocks with very high coke-forming properties, which were not amenable to catalytic cracking according to conventional methods of the art, can be cracked according to the present invention by preheating the charge in a regeneration zone. .

According to a preferred embodiment of the process of the invention, the fresh hydrocarbon feedstock prior to indirect heat exchange with the regenerated catalyst will have a temperature of at least gθ°C and as high as 2jO°C. . Preferably, the new feedstock is in the range 2j
It is heated by the heat exchange to a temperature of O to t;as°C. 2
A feedstock of 0-130°C is said to be relatively low temperature, /! ;0~. A feedstock of 2jO<0>C is said to be relatively hot. The fresh feedstock is heated according to the method of the invention, preferably to a temperature range 32j-≠00°C.

Temperatures in the range 3jO~≠00°C should not be maintained for long periods of time: because thermal decomposition can then begin. However, this danger is fed directly to the reaction zone.

As previously mentioned, it is desirable but often impossible to perform fluid catalytic cracking with complete CO combustion. This is particularly difficult when attempting to process heavy coking feedstocks in reactor systems designed for light feedstocks such as gas oil.

The method of the present invention, in which heat is extracted from the regeneration zone, makes it possible to operate with complete CO calcination using a wide range of feedstocks. Therefore, the present invention oxidizes the coke deposited on the spent catalyst to complete carbon dioxide and increases the temperature of the regeneration zone to 72! ; Also relates to methods of keeping the temperature below ℃.

The temperature 7.23°C can be considered an upper limit for the temperature of the regeneration zone, but ';/2! It is clear that it is safe to operate at temperatures below 0.degree. C., for example keeping the upper limit at 700.degree. On the other hand, make sure that the temperature of the playback zone is not too low, for example, below 10℃.
In this case, the combustion of the coke deposits is too slow, and furthermore, the catalyst does not reach a sufficiently high temperature to vaporize the charge material in the cracking zone.

It is within the scope of this invention to cool a portion of the preheated feedstock by indirect heat exchange with a suitable cooling medium, such as water, to remove excess heat that cannot be stored in the reactor system. This may be the case with very high coke-forming feedstocks, especially when the present invention is operated with complete CO combustion during spent catalyst regeneration. In such a case, the temperature is 72! ; since a large amount of heat will have to be extracted from the catalyst bed to prevent temperatures from rising above 10°F, at least a portion of the preheated hydrocarbon feedstock may be removed by indirect heat exchange with a cooling medium such as water. Again it would have to be cooled externally.

The heat thus contained in the cooling medium can be used in other units of the refinery in which the catalytic cracking unit is located. That is, in a particular example of the process of the invention, at least a portion of the feedstock after being heated by indirect heat exchange with the catalyst to be regenerated is removed outside the regeneration zone by indirect heat exchange with the cooling medium. cooled down.

The feedstock thus preheated and further partially recooled may be fed directly to the reaction zone, and if only a portion of the feedstock is recooled, it may be mixed with other parts of the feedstock. not recooled after.

However, if a certain amount of recirculation is performed, the temperature stability of the feedstock entering the reaction zone and the flexibility of the process increases. Preferably, a portion of the feedstock heated and then cooled as described above is combined with fresh feedstock to be heated by indirect heat exchange with the catalyst to be regenerated.

It has been found that when (some) feedstock is heated and cooled again, it is uneconomical for the feedstock to be cooled to be cooled to a temperature higher than the temperature of the fresh hydrocarbon feedstock: because This is because the feedstock itself can be easily cooled, for example by simply mixing the fresh feedstock and the heated feedstock. therefore,
Preferably, at least a portion of the heated feedstock is cooled to a temperature no higher than the temperature of the feedstock to be heated.

In the latter case, at least a portion of the heated feedstock is
Depending on the particular temperature of the feedstock to be heated, it is preferably cooled to a temperature ranging from gOo to 750°C.

As mentioned above, all or a portion of the heated feedstock will be cooled after being heated in the regeneration zone.

However, for process economics it is preferred to cool between 3 and 10 of the heated feedstock before mixing with fresh feedstock. This amount is determined by the circulation ratio 0.0, where the circulation ratio is defined as the ratio of the recycled feedstock to itself. //:0. ! ; becomes 0.

In some cases, so-called "torch oil" is used in the regeneration zone.
It is advantageous to combust "rch oil".

This oil, in contrast to so-called cycle oils, is part of the reaction products which are very difficult to decompose and are not suitable for recycling with fresh feedstock. It is advantageously used, for example, as heating oil in regeneration zones, especially when optimum yields of middle distillates are aimed at.

The extra heat added is easily transferred to the feedstock according to the method of the invention. The invention therefore also relates to a method in which a hydrocarbon fuel is combusted in a regeneration zone.

The present invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a simplified process diagram of a fluid catalytic cracking reactor system. FIG. 2 is a graph of the effect of feedstock preheating on the regeneration reactor and catalyst-to-oil ratio and is detailed in the Example section.

Described with reference to FIG. 1, the new feedstock is
The feedstock is heated via pipe /7 with regenerator coils /B and heat exchanger /g and led to pipe 3. It is also possible to pass part of the feedstock back through the regenerator coil/B via pipe/7, in which case a more stable temperature of the feedstock in pipe/7 and a fluidized bed/
3, resulting in a more stable temperature. The regenerator coil/O is covered with a fluidized bed/3 of catalyst particles to be regenerated.

In some cases it may be advantageous to provide seven more heat exchangers in the tube/tube before or after the branch 2 in order to cool or heat the fresh feedstock which is too hot or cold.

Particularly when processing very heavy coking feedstocks, it is also possible to install a heat exchanger/g in the recirculation pipes: since (the vaporization of heavy feedstocks in the lift pot This is because the high temperature of the feedstock in tube 3 or /7 has to be combined with a large cooling effect in the regenerator due to the excess coke that is burnt off. The feedstock passes through pipe 3 to a lift pot (1ifpot).
)≠, where the feedstock is contacted with high pressure regenerated catalyst fed through standpipe j. The feedstock vaporizes and passes in an upward plug flow through the standpipe reactor B and into the fluidized bed 7 of reactor G, carrying the catalyst particles with it. The gaseous vaporized liquid decomposition products are removed from the top of the vessel via conduit 7. The conduit is connected to a cyclone (not shown) which removes entrained solid catalyst particles from the gas stream and returns these particles to the fluidized bed 7 via diplegs (not shown). The spent catalyst particles are stripped from the adhering hydrocarbons in a stripper vessel 10 located below the reactor vessel.

The spent catalyst particles that have been removed are then fed to the regenerator vessel/2 via the standpipe//. In this vessel, a fluidized bed /3 of catalyst particles is maintained, usually with oxygen, by a stream of oxygen-containing gas fed via a nozzle tube /≠. The carbon deposits on the catalyst particles are combusted in bed/3, and the regenerated catalyst particles pass through the standpipe j and return to the bottom pot≠. Combustion gases are removed from the top of the regenerator vessel /2 through conduit /j.

In the method according to the invention, the tube 2 is not used, or at least not necessarily necessary. If present as a remnant of a conventional reactor system (when a conventional system is modified to carry out the process of the invention), this may be used for start-up purposes or as a safety relief tube.
) would be advantageous. For this purpose, a valve (not shown) is provided at the connection between the pipes 2 and 2, so that the feedstock can be directed, in whole or in part, into the pipes as desired.

Example: A fluid catalytic cracking unit in a refinery is first operated normally, but with complete CO combustion. However, in this form of operation, the increase in feed temperature is
It is only possible to process feedstocks at low temperatures (in the range 30-g0<0>C), since acceptance of the regenerator temperature results in an unacceptable increase. In the regenerator, high oxygen slip (excess oxygen) must be retained to cool the regeneration bed.

In order to apply the method of the invention, this unit has been modified by providing a preheating coil in the regenerator. Due to the time-determined size and shape of this regenerator, two parallel sets of these coils in series are provided. The coil occupies the cross section of the vessel between the lowest level of the draw-off bin and the top of the manhole. each coil has its own supply inlet and outlet;
Each coil constitutes a self-supporting beam requiring only end supports. Additionally, each coil is configured to extend through the manhole. The selected tube alloy has a maximum reactor temperature of 700°C and a design pressure of
n pressure ), allowing operation at 23 bar absolute. In the design, necessary attention has been paid to thermal expansion. The total length of piping inside the reactor is sufficient to heat the feed to 200° C. to 370° C. at a feed rate of 3000) 77 days.

The reaction conditions and the results of the steps taken are shown in the following table. Two reactor pressures Parr /, 3
/, 3 catalyst to oil ratio ta
Maximum regenerator temperature ℃ 6 O O Initial temperature of feed material CI- and 0 200 Temperature at which feed material enters the funnel C3040370 Regenerator oxygen slip Capacity 43 2 Regenerator air pressure 1/9. ! ; 15 Conradran number mass of feed material 0. G, 2.0
0.4t O,≠Ni equivalent of feed material ppm
O,≠0. 'l-/,'IO,'A catalyst zeolite content 9 mass% 333! r1
The measurements were made as described in French Patent Specification No. 2.330.7 j &.

Obviously, the operational flexibility is increased by carrying out the preheating according to the invention. The table shows three cases according to the invention: /) Feedstocks that produce more coke can be processed.

6. Feedstocks containing many metals can be processed.

3) More active/selective catalysts can be used.

Moreover, less oxygen is used in the regenerator for cooling purposes, and warmer feedstock can be processed, avoiding the need to pre-cool the feedstock.

FIG. 2 shows the effect of preheating the feed material in the regenerator coil/B according to the present invention. Regeneration zone temperature T reg is plotted as a function of catalyst to oil ratio C10.

Clearly, the decrease in catalyst feed rate C is 72! ; results in an increase in T reg that should be kept below °C. However, a reduction in C is necessary to reduce the severity of decomposition, for example when using more active/selective catalysts.

Two cases are shown for a fluid catalytic cracking reactor system according to FIG. Series A is a conventional heat balanced catalytic cracking operation using tube 2 and series B is a regeneration zone 7 without recirculation through tube/7 or heat exchange in exchanger/♂. In accordance with the present invention, the feed material is preheated and the tube is heated at step 2. For all measurements, the feed is introduced into the tube/tube at a temperature of 200<0>C and the reactor/standtube outlet temperature is maintained at 520<0>C. Curve A shows the results of series A heat-balanced operation, and curve B shows the result of series B heat-balanced operation. are doing. Curve B is shifted towards lower C mortality and lower regenerator temperatures so that in the process according to the invention a more selective/active catalyst and/or a more coking-forming feedstock is used.
Maximum regenerator temperature 72! ; It can be used without exceeding ℃.

[Brief explanation of the drawing]

FIG. 1 shows a simplified flow diagram of a fluid catalytic cracking reactor system. FIG. 2 graphically illustrates the effect of preheating the feedstock on catalyst-to-oil ratio and regenerator temperature. ≠...Lift pot, B...Vertical pipe reactor, 7...
・Fluidized bed, g... Reactor container, 10... Stripper container, 7.2... Regenerator container, /3... Fluidized bed, /
B...Regenerator coil, 7g...Heat exchanger. Agent's name: Kawahara 1) - Ho

Claims (1)

[Scope of Claims] (1) A method for fluid catalytic cracking of a hydrocarbon feedstock in a reactor system including at least a cracking zone and a regeneration zone that communicate with each other, the hydrocarbon feedstock being heated at a high temperature in the cracking zone. in contact with a decomposition catalyst of
50℃, pressure range from atmospheric pressure to absolute pearl,
vaporizing at least a portion of the feedstock under cracking conditions with a catalyst-to-oil ratio of less than 7 and subsequently cracking into low-boiling hydrocarbon products, and then separating the low-boiling hydrocarbon products from the spent catalyst; The spent catalyst containing coke deposits is simultaneously passed through a regeneration zone where an oxygen-containing gas is passed through the catalyst bed, thus oxidizing the coke deposits with the generation of heat. In a process for fluid catalytic cracking of hydrocarbon feedstocks, the method comprises: recovering and heating the catalyst; and then returning the hot regenerated catalyst to the cracking zone. By removing heat from the bed of catalyst being regenerated, the temperature of the regeneration zone can be reduced to 72! ;'C, thus heating the feedstock to a temperature of at least 200°C, after which the feedstock is introduced into a cracking zone and in direct contact with the hot regenerated catalyst to 200°C.
A method for fluid catalytic cracking of the hydrocarbon feedstock, characterized in that the hydrocarbon feedstock is vaporized at a temperature higher than °C. (2) In the method of paragraph 1 above, the indirect heat exchange between the catalyst to be regenerated and the fresh hydrocarbon feedstock comprises seven or more heat exchangers located in the bed of the catalyst to be regenerated. A method as described above, characterized in that it is carried out by passing a wire feed through a tube. (3) In the method according to item 1 or 2 above,
A method as described above, characterized in that the fresh hydrocarbon feedstock prior to indirect heat exchange with the catalyst to be regenerated has a temperature of at least 0°C and as high as 230°C. (4) In the method according to any one of paragraphs 1 to 3 above, the new feedstock is heated to a temperature of 2
The above method, characterized in that heating is carried out to a temperature in the range of 30 to ≠2j°C. (5) The method according to item 1, wherein the new feedstock is heated to a temperature in the range of 325 to ≠00°C. (6) In the method according to any one of paragraphs 1 to 5 above, the temperature of the regeneration zone is maintained below 7.25°C during complete oxidation of coke deposits on the spent catalyst to carbon dioxide. The method characterized in that: (7) The method according to any one of items 1 to 6 above, wherein the temperature of the reproducing zone is maintained in a range of 70 to 700°C. (8) In the method according to any one of paragraphs 1 to 7 above, at least a portion of the feedstock after being heated by indirect heat exchange with the catalyst to be regenerated is outside the regeneration zone, and is heated by indirect heat exchange with the catalyst to be regenerated. A method as described above, characterized in that the cooling is performed by indirect heat exchange. (9) In the method of paragraph g above, at least a portion of the heated feedstock is cooled and then added to the fresh feedstock to be heated by indirect heat exchange with the catalyst to be regenerated. Said method, characterized in that it is brought together again. α1 A method according to any of paragraphs K or 7 above, characterized in that at least a portion of the heated feedstock is cooled to a temperature no higher than the temperature of the new feedstock to be heated. The said method. Qυ Process according to paragraph 1Q above, characterized in that at least a portion of the heated feedstock is cooled to a temperature in the range gO to /jO°C. α-Bu In the method according to any one of items 7 to 77, the heated feedstock may be heated from //3 to //.
10 is cooled and then mixed with fresh feedstock. 0.13 A method according to any of paragraphs 1 to 72, characterized in that the hydrocarbon fuel is combusted in a regeneration zone.