KR20110101214A - Apparatus for regenerating catalyst - Google Patents

Abstract

The present invention discloses a catalyst distributor and process for rolling catalyst over a regenerator vessel. The nozzles, arranged angularly with respect to the header of the distributor, evenly spread over the entire cross section of the catalyst bed.

Description

Catalytic Regeneration Unit {APPARATUS FOR REGENERATING CATALYST}

FIELD OF THE INVENTION The field of the present invention relates to the distribution of catalysts in catalyst regenerator vessels.

Fluid catalytic cracking (FCC) is a hydrocarbon conversion process achieved by contacting a catalyst consisting of finely divided particulate material with a hydrocarbon in a fluidization reaction zone. In its catalytic cracking the reaction is carried out in the absence of significantly added hydrogen or in the absence of hydrogen consumption, as opposed to hydrocracking. As the decomposition reaction proceeds, a significant amount of higher carbon material called coke is deposited on the catalyst. The hot regeneration operation in the regenerator zone burns coke from the catalyst. The coke containing catalyst, referred to herein as a coking catalyst, is continuously removed from the reaction zone and exchanged for essentially a coke free catalyst derived from the regeneration zone. Fluidization of catalyst particles by various gas streams allows for catalyst transport between the reaction zone and the regeneration zone.

The general purpose of this configuration is to maximize product yield from the reactor while minimizing operating and equipment costs. Optimization of feedstock conversion generally requires the complete removal of coke from the catalyst. Such essential complete removal of coke from the catalyst is often referred to as complete regeneration. Complete regeneration produces a catalyst having coke below 0.1 wt%, preferably below 0.05 wt%. To obtain full regeneration, the catalyst must be in contact with oxygen for a residence time sufficient to allow complete combustion.

Conventional regenerators typically include a vessel holding as a vessel a combustion gas distributor for supplying air or other oxygen containing gas to the coking catalyst inlet, the regenerated catalyst outlet and a layer of catalyst present in the vessel. The cyclone separator removes the catalyst entrained in the flue gas before it is discharged from the regenerator vessel.

There are several types of catalyst regenerators currently in use. Conventional bubbling layer regenerators typically have only one chamber in which air is bubbled through the dense catalyst layer. Coking catalyst is added and regenerated catalyst is withdrawn from the same dense catalyst bed. Relatively few catalysts are entrained in the combustion gases exiting the dense bed. The two-stage bubbling layer holds two chambers. Coking catalyst is added to the dense bed in the first chamber and partially regenerated by air. The partially regenerated catalyst is transported to the dense bed in the second chamber and is completely regenerated by air. This fully regenerated catalyst is discharged from the second chamber.

Complete catalyst regeneration can be performed in a dilution phase rapid fluidized combustion regenerator. Coking catalyst is added to the bottom chamber and transported upwards by air under rapid fluidization flow conditions while at the same time the catalyst is fully regenerated. This regenerated catalyst is separated from the flue gas by the primary separator as it enters the upper chamber, and the regenerated catalyst and the flue gas are removed from the upper chamber. US 4,197,189 and US 4,336,160 teach no vertical tube combustion zones in which rapid fluidization flow conditions are maintained to perform complete combustion in the catalyst bed collected from the top of the riser without the need for further combustion.

Nitrogen oxides (NO _X ) are generally present in the regenerator flue gas, but should be minimized due to environmental issues. The production of NO _X is undesirable because it reacts with volatile organic chemicals and sunlight to form ozone. Regulated NO _X emissions generally include nitrogen monoxide (NO) and nitrogen dioxide (NO ₂ ), but FCC processes may also produce N ₂ O. In FCC regenerators, NO _X is produced almost entirely by oxidation of nitrogen compounds that originate from the FCC feedstock and accumulate in the coking catalyst. Under FCC regenerator operating conditions, there is a slight NO _x production associated with oxidation of N ₂ from air combustion. Small excess air in regenerators is often used by refiners to keep NO _x emissions low.

After burn is a phenomenon that occurs when the hot flue gas separated from the regenerated catalyst contains carbon monoxide, which is burned with carbon dioxide. A catalyst that no longer acts as a heat sink can absorb its heat, bringing the ambient equipment to higher temperatures and possibly forming an atmosphere that promotes the production of nitrogen oxides. Incomplete combustion to carbon dioxide can result from poor fluidization or aeration of the coking catalyst in the regenerator vessel, or poor distribution of the coking catalyst into the regenerator vessel.

In order to avoid afterburning, many refiners use expensive platinum added to the FCC catalyst to promote complete combustion with carbon dioxide before separating the flue gas from the catalyst at the low excess air rate required to control NO _x to a low level. And carbon monoxide promoters (CO promoters). While low excess oxygen rates reduce NO _X , the simultaneous use of CO promoters often needed for post combustion can further compensate for the benefits of low excess oxygen rates. The CO promoter reduces CO emissions but increases NO _X emissions in the regenerator flue gas.

On the other hand, many refiners use high levels of CO promoter and high levels of excess oxygen, especially when operated at high throughput, to accelerate combustion and reduce post combustion in the regenerator. This practice can increase NO _x to 10 times or less of 10-30 ppm possible when the platinum CO promoter is not used and the excess oxygen rate is controlled to 0.5 volume percent or less.

The improved method was to prevent the production of afterburns and nitrogen oxides. Complete mixing of catalyst and combustion gases in the regenerator promotes more uniform temperature and catalyst activity which promotes more efficient combustion of coke from the catalyst.

Summary of the Invention

The inventors have discovered an apparatus and process for distributing coking catalyst to a regenerator vessel, leading the catalyst in the catalyst bed of the regenerator to equilibrate the temperature in the catalyst bed. More uniform temperatures in the dense bed promote more uniform exposure of the coking catalyst to oxygen, resulting in higher regeneration efficiency. The regeneration is also more predictable and thus more predictable and therefore controllable for complete combustion with carbon dioxide without the need for a CO promoter to prevent post combustion. Without the post combustion and CO promoters, less nitrous oxide is generated in the flue gas.

The catalyst distributor includes a header having a long axis and an annular nozzle in communication with the header. The nozzle defines an acute angle with the long axis and angularly discharges the catalyst from the header into the regenerator vessel. In an embodiment, the bottom of the nozzle is disposed at the bottom quarter of the header. In an embodiment, the nozzle discharges the catalyst horizontally. In a further embodiment, the catalyst distributor is submerged in the catalyst bed.

Brief description of the drawings

1 is a schematic front view of an FCC unit incorporating the catalyst distributor of the present invention.

2 is a plan view of the regenerator vessel of FIG. 1 showing a catalyst distributor of the present invention.

3 is an enlarged partial side view of the catalyst distributor of the present invention.

4 is a schematic front view of an alternative FCC unit incorporating a further embodiment of the catalyst distributor of the present invention.

5 is a schematic front view of an alternative FCC unit incorporating a further embodiment of the catalyst distributor of the present invention.

6 is a radar plot of the catalyst distribution provided by the present invention.

Detailed description of the invention

Although other uses are contemplated, the process and apparatus of the present invention may be implemented in an FCC unit. 1 shows an FCC unit comprising a reactor section 10 and a regenerator vessel 50. The regenerated catalyst conduit 12 moves the regenerated catalyst from the regenerator vessel 50 to the vertical tube 20 of the reactor section 10 at a rate controlled by the control valve 14. Fluidization media, such as steam derived from nozzle 16, is upwardly passed through vertical tube 20 at a relatively high density until a plurality of feed injection nozzles 18 intersect a flow stream of catalyst particles to inject a hydrocarbon feed. Transport the regenerated catalyst. The catalyst contacts the hydrocarbon feed to produce a smaller cracked hydrocarbon product and simultaneously deposits coke on the catalyst to produce a coking catalyst.

Conventional FCC feedstocks or high boiling hydrocarbon feedstocks are suitable feeds. The most common of such conventional feedstocks is “vacuum gas oil” (VGO), which is a hydrocarbon material having a boiling point range of 343 to 552 ° C. (650 to 1025 ° F.) produced by reduced pressure fractionation of atmospheric residues. to be. Such fractions are generally low in coke precursors and heavy metal contamination that may act to contaminate the catalyst. Heavy hydrocarbon feedstocks to which the present invention may be applied include bottom heavy oil derived from crude oil, heavy bitumen crude oil, shale oil, tar sand extract, deasphalted residue, products derived from coal liquefaction, atmospheric pressure and reduced pressure crude oil. The heavy feedstock in the present invention also includes a mixture of the above hydrocarbons, and the foregoing list is not exhaustive.

The resulting mixture continues upwardly through the vertical tube 20 such that a plurality of diengaing arms 22 tangentially and horizontally direct the mixture of gas and catalyst from the top of the vertical tube 20 to the port 24. The discharge into the separation vessel 26 through) leads to the top of which gas separation from the catalyst is carried out. The transport conduit 28 separates the coking catalyst from the hydrocarbon vapor stream by conveying hydrocarbon vapor, including stripped hydrocarbon, stripping medium, and entrained catalyst, to one or more cyclones 30 in the reactor vessel 32. Done. Reactor vessel 32 at least partially contains a separation vessel 26, which separation vessel 26 is considered part of the reactor vessel 32. Collection chamber 34 in reactor vessel 34 accumulates a hydrocarbon vapor stream separated from cyclone 30 for passage to outlet nozzle 36 and eventually to a fractional distillation recovery zone (not shown). The dipleg 38 discharges the catalyst from the cyclone 30 into the lower portion of the reactor vessel 32, thereby confining a port 42 within the wall of the separation vessel 26 to adsorb or entrain the hydrocarbon adsorbed with the catalyst. ) Is passed into the stripping section 40 of the reactor vessel 32 crossed. The catalyst separated in the separation vessel 26 is passed directly into the stripping section 40. Stripping section 40 contains baffles 43 and 44 or other device that facilitates mixing between the stripping gas and the catalyst. The stripping gas enters the bottom of the stripping section 40 and reaches one or more distributors 46 through conduits. The coking catalyst leaves stripping section 40 of reactor vessel 32 through reactor catalyst conduit 48 and passes through regenerator vessel 50 at a rate controlled by control valve 52. The coking catalyst derived from reactor vessel 32 contains carbon in an amount of 0.2 to 2% by weight, usually present in the form of coke. Although the coke consists mainly of carbon, it may contain from 3 to 12% by weight of sulfur and other materials as well as hydrogen.

Regenerator vessel 50 may be a bubbling layer type of the ashing machine as shown in FIG. 1. However, other regenerator vessels and other flow conditions may be suitable for the present invention. Reactor catalyst conduit 48 having an inlet 48a in downstream communication with reactor vessel 32 may supply coking catalyst to regenerator riser 54 such that air or other oxygen-containing combustion gases are fed into riser gas line 52a. May be added through the outlet of the combustion gas line 55. It is also contemplated that other lift gas may be used to raise the coking catalyst over regenerator riser 54. In the embodiment of FIG. 1, the coking catalyst descends the reactor catalyst conduit 38, leading to a bight in communication with the regenerator vertical pipe 54. The coking catalyst is bent around by the lift as it is lifted by the lift gas derived from the vertical tube gas line 55a having an outlet in upstream communication with the regenerator vertical tube 54. The coking catalyst then travels over regenerator riser 54 and enters regenerator vessel 50 through coking catalyst inlet 56. The coking catalyst has a catalyst distributor 60 having an inlet 64 in downstream communication with a catalyst inlet 56 and an outlet from a vertical gas line 55a for dispensing the coking catalyst to the regenerator vessel 50. Is delivered. Regenerator riser 54 may be terminated at top head 62. Regenerator riser 54 is a portion of reactor catalyst conduit 48 disposed immediately below catalyst dispenser 60 while directly upstream of catalyst distributor 60. Inlet 64 to header 66, which may include a longitudinal pipe, may be disposed below top head 62. Additionally, header 66 may be perpendicular to player riser 54. The catalyst distributor 60 includes one or more, preferably a plurality of nozzles 68 in communication with the header for discharging the catalyst into the regenerator vessel 50. In certain embodiments, the catalyst distributor 60 discharges the coking catalyst below the top surface of the dense catalyst layer 58, and the catalyst distributor 60 is preferably submerged in its dense catalyst layer below its top surface. . In addition, the catalyst distributor 60 is disposed in an eccentric position in the reactor vessel 50 and radially discharges the catalyst from the distributor into the dense catalyst layer 58 across the entire cross section of the dense catalyst layer 58. . The combustion gas in the regenerator riser 54 helps to release the catalyst from the catalyst distributor 60 into the bed and also provides the oxygen needed for the combustion requirements.

Oxygen-containing combustion gas, typically air, originating from the combustion gas line 55 is primarily delivered to the regenerator vessel 50 by the combustion gas distributor 80 below the catalyst distributor 60. In any embodiment, the combustion gas distributor 80 distributes most of the combustion gas to the regenerator vessel 50 and is supplied by the combustion gas line 55b from the combustion gas line 55 regulated by a control valve. The flutes 82 in the flue gas distributor 80 are arranged such that the flue gas is evenly released over the entire cross section of the regenerator vessel 50. Oxygen in the combustion gas is contacted with the coking catalyst to burn carbon thick deposits from the catalyst to regenerate the catalyst and generate flue gas. The catalyst may be entrained with the flue gas rising in the regenerator vessel 50. Therefore, the catalyst entrained in the flue gas enters the cyclone separators 86 and 88 for centrifugally separating the flue gas from heavier catalyst particles. The catalyst particles fall into the deep legs 87 and 89 and flow back into the dense catalyst layer 58. The cleaned flue gas rises from the cyclone separators 86 and 88 to the plenum 90 through the conduit and exits through the flue gas outlet 92. The regenerated catalyst exits the dense catalyst layer 58 through the regenerated catalyst outlet 96 in the regenerator vessel 50. The regenerated catalyst conduit 12 in downstream communication with the regenerated catalyst outlet 96 delivers the regenerated catalyst back to the reactor riser 20 at a rate controlled by the control valve 14.

Combustion gases such as air may be used to raise the coking catalyst over regenerator riser 54, which may allow regeneration in regenerator riser 54. The combustion gas leading to regenerator riser 54 may be 10-20% by weight of the combustion gas leading to regenerator vessel 50. If the air is combustion gas, typically 12-15 kg (lbs) of air per kg (lb) of coke fed on the catalyst leading to the regenerator are required. The temperature of the regenerator vessel 50 is 500 to 900 ° C, usually 600 to 750 ° C. The pressure in regenerator vessel 50 is preferably 173 to 414 kPa (gauge) (25 to 60 psig). The supercritical velocity of the combustion gases is typically below 1.2 m / s (4.2 ft / s) and the density of the dense bed is typically greater than 320 kg / m ³ (20 lb / ft ³ ), depending on the nature of the catalyst.

2 shows a plan view of the catalyst distributor 60 over the air distributor 80 and its flutes 82. The header 66 defines an longitudinal axis L and an angular nozzle 68a in downstream communication with the header 66. This angled nozzle 68a defines an acute angle α with the longitudinal axis L of the header 66. In other words, the longitudinal axis defined by the angular nozzle 68a defines an acute angle α with this longitudinal axis L. The angular nozzle 68a discharges the catalyst into the regenerator vessel 50 at an acute angle α with respect to the longitudinal axis L. As shown in FIG. In certain embodiments, the plurality of nozzles 68a-68d, each in downstream communication with the header 66, have an axis that defines an acute angle with the longitudinal axis L. The nozzles 68b-68d define acute angles β, γ, and δ, respectively, with the longitudinal axis L of the header 66. In other words, the longitudinal axes a-d defined by the nozzles 68a-68d define an acute angle with the longitudinal axis L. FIG. The plurality of nozzles 68a-68d discharge the catalyst into the regenerator vessel 50 at an acute angle with the longitudinal axis L. FIG. The proximal nozzle 68e is perpendicular to the longitudinal axis L. As shown in FIG. Similarly, the proximal nozzle 68f is perpendicular to the longitudinal axis L. FIG. In other words, the longitudinal axes e and f respectively define the perpendicular angles ε and ξ to the longitudinal axis L by the nozzles 68e and 68f. The nozzles 68a, 68b and 68f are on one side of the header 66 and the nozzles 68c, 68d and 68e are on the opposite side of the header 66. The nozzles opposed to each other may have the same length and may define the same angle with the longitudinal axis (L). In certain embodiments, the angled nozzles on the same side of the header 66 define angles α and β and γ and δ, respectively, that are different, with the longitudinal axis L. The catalyst distributor may include a distal nozzle 68g on the outer end 70 of the header 66 that defines the longitudinal axis g aligned with the longitudinal axis L. FIG.

In any embodiment, the smallest angle that the nozzles 68a-68g define with the longitudinal axis L is continuous as the nozzle is located further away from the inlet 64 and closer to the outer end 70. Decreases. The nozzle discharges the catalyst as an angle to the longitudinal axis L at a continuously decreasing angle as the distance from the inlet end increases. This allows the nozzle to radially release the catalyst at the same position across the entire cross section of the layer from the eccentric position in the regenerator vessel 50. Additionally, in any embodiment, the lengths of the nozzles 68a-68f on both sides of the header 66 are continuous as the nozzles are located further away from the inlet 64 and closer to the outer end 70. To increase. The catalyst distributor 60 is disposed in one quadrant of the regenerator vessel 50, and the longitudinal axis L may intersect the cross-sectional center C of the regenerator vessel 50. FIG. 2 also shows the opposite position of the outlet 96 relative to the dispenser 60 in which the outlet 96 is arranged in the quadrant opposite to the quadrant containing the distributor 60.

3 provides an enlarged partial front view of a catalyst distributor 60 with a header 66 defining a height H. FIG. The bottom part 72a of the nozzle 68a is arrange | positioned at the bottom part which is 1/4 of the height H of the header 66. As shown in FIG. In certain embodiments, bottom portion 72a is defined as the lowest point of the inner circumference of nozzle 68a. The positioning of the nozzle 68a relative to the header 66 does not guarantee catalyst stagnate at the header 66. The nozzle 68a also has a height h. In certain embodiments, at least 50% of the height h of the nozzle 68a is disposed at 50% or less of the height H of the header 66. 3 also illustrates in some embodiments that the longitudinal axis defined by the nozzle 68a is horizontal. In certain embodiments, the longitudinal axis L of the header 66 is also horizontal. In further embodiments, the bottoms 72a-72f of all nozzles 68a-68f are disposed at the bottom which is one quarter of the height H of the header 66, but only the nozzles 68a, 68b and Only 68f) is shown in FIG. 3. In certain embodiments, bottoms 72a-72f are defined as the lowest point of the inner circumference of the nozzles 68a-68f. In any embodiment, all the nozzles 68a-68f have a height h, and at least 50% of the height h of the nozzles 68a-68f is no more than 50% of the height H of the header 66. Is placed on. In further embodiments, the longitudinal axis defined by all nozzles 68a-68f is horizontal, but only nozzles 68a, 68b and 68f are shown in FIG. 3. Aligned distal nozzle 68g is also shown in FIG. 3. The distal nozzle 68g also has an axis g that is horizontal and aligned with the longitudinal axis L. FIG. Horizontal nozzles 68a-68g discharge the catalyst horizontally from the header 66.

4 shows any embodiment of a regenerator vessel 50 ′ which is a combustor type of regenerator, the combustor type of hybrid turbulent bed-rapid fluidization in a high efficiency regenerator vessel 50 ′ to completely regenerate the coking catalyst. Conditions (hybrid turbulent bed-fast fluidized conditions) can be used. Elements of FIG. 4 having the same configuration as in FIG. 1 have the same reference numerals as in FIG. Elements of FIG. 4 that have different configurations than the corresponding elements in FIG. 1 have the same reference numerals but are denoted by the prime symbol ('). The construction and operation of the reaction section 10 in FIG. 4 is basically the same as in FIG. 1, and the foregoing description is incorporated by reference in the embodiment of FIG. 4. However, reactor catalyst conduit 48'is in communication with catalyst distributor 60 '. Inlet 48a of reactor catalyst conduit 48 ′ is in communication with reactor vessel 32. A predominant portion of the reactor catalyst conduit 48 'is disposed above the catalyst distributor 48'. Fluidizing gas, which may be combustion gas, is provided by fluidizing gas line 55a 'to propel the coking catalyst through catalyst distributor 60'. However, the fluidizing gas derived from fluidizing gas line 55a 'requires a relatively smaller amount than in the embodiment of FIG. 1, which is of the reactor catalyst conduit 48' directly upstream of catalyst distributor 60 '. This is because gravity assists in transporting the coking catalyst in the reactor catalyst conduit 48 'because the portion is disposed above the catalyst distributor 60'. The coking catalyst regulated by the control valve 52 descends the reactor catalyst conduit 48 'and enters the lower chamber or first chamber 102 of the combustor regenerator vessel 50' via the catalyst inlet 56 '. .

A catalyst distributor 60 'having a catalyst inlet 56' and an inlet 64 'in downstream communication with an outlet from fluidized gas line 55a' is provided with a lower chamber 20 of combustor regenerator vessel 50 '. To the coking catalyst. Inlet 64 ′ communicates with header 66, which may define a longitudinal axis. Additionally, the header 66 may be angled directly upstream of the reactor catalyst conduit 48 '. The catalyst distributor 60 'includes one or more, preferably a plurality of nozzles 68 in communication with the header 66 for discharging the catalyst into the lower chamber 102 of the regenerator vessel 50'. In any embodiment, the catalyst distributor 60 'discharges the coking catalyst below the top surface of the dense catalyst layer 58', and the catalyst distributor 60 'is immersed in its dense catalyst layer below its top surface. It is desirable to have. In addition, the catalyst distributor 60 'is disposed in an eccentric position in the combustor regenerator vessel 50' and crosses the entire cross section of the dense catalyst layer 58 'from the distributor into the dense catalyst layer 58'. Is emitted radially. The fluidizing gas derived from the fluidizing gas line 95 'helps eject the catalyst from the catalyst distributor 60' into the bed. If the fluidizing gas contains oxygen to provide oxygen for combustion requirements, the fluidizing gas line 55a may be a branch derived from the combustion gas line 55 '. The header 66 and nozzle 68 of the catalyst distributor 60 'are configured as described with respect to FIGS.

The combustion gas distributor 80 ′ distributes gas from the distributor gas line 55b ′ to the lower chamber 102. Combustion gas line 55 'may supply distributor gas line 55b'. Combustion gas is brought into contact with the coking catalyst entering from the catalyst distributor 60 ′ and the catalyst is heated at supercritical velocity of the combustion gas in the lower chamber 102, which is at least 1.1 m / s (3.5 ft / s) under rapid fluidization flow conditions. Raise up. In certain embodiments, the flow conditions in the lower chamber 102 are at a catalyst density of 48 to 320 kg / m ³ (3 to 20 lbs / ft ³ ) and of 1.1 to 2.2 m / s (3.5 to 7 ft / s). Supercritical gas velocity. In any of the embodiments. In order to accelerate the combustion of the coke in the lower chamber 102, the hot regenerated catalyst from the dense catalyst layer 59 in the upper or second chamber 104 is subjected to an external recycle catalyst conduit 108 regulated by the control valve 106. May be recycled into the lower chamber 102 via. The hot regenerated catalyst enters the inlet of the recycle catalyst conduit 108 in downstream communication with the upper chamber 104. The outlet end of the recycle catalyst conduit may be communicated upstream with the catalyst distributor 110 in the lower chamber 102. Although described differently here, it is contemplated that the recycle catalyst may be added to the lower chamber 102 without using the catalyst distributor 110. In addition, although recycle catalyst may be added to lower chamber 102 using catalyst distributor 110, coking catalyst in reactor catalyst conduit 48 may be added without distributor 60 ′. The hot regenerated catalyst may enter the lower chamber 102 through a second catalyst distributor, which may be disposed at a higher height than the catalyst distributor 60 '. Catalyst distributors 60 'and 110 are preferably disposed on opposite sides of regenerator vessel 50'. Recirculation of the regenerated catalyst is accomplished by mixing the high temperature catalyst derived from the dense catalyst layer 59 with the relatively cold coking catalyst derived from the reactor catalyst conduit 48 ′ entering the lower chamber 102. 102) raises the overall temperature of the catalyst and gas mixture. The predominant portion of the recycle catalyst conduit 108 and the portion of the recycle catalyst conduit 108 immediately upstream of the distributor 110 are disposed above the catalyst distributor 110.

Catalyst distributor 110 having a catalyst inlet 116 and an inlet 114 in downstream communication with an outlet derived from recycle gas line 55c delivers the recycled regenerated catalyst to the lower chamber 102 of the combustor regenerator vessel 50 '. ) If the recycle gas contains oxygen, the gas may be a branch derived from the combustion gas line 55. Inlet 114 communicates with header 66, which may include a longitudinal axis. Additionally, the header 66 may be angled directly upstream of the recycle catalyst conduit 108. Catalyst distributor 110 includes one or more, preferably a plurality of nozzles 68 in communication with header 66 for dispensing catalyst into combustor regenerator vessel 50 '. In any embodiment, the catalyst distributor 110 discharges the coking catalyst below the top surface of the dense catalyst layer 58 ', and the catalyst distributor 110 is submerged in its dense catalyst layer below its top surface. desirable. In addition, the catalyst distributor 110 is disposed in an eccentric position in the lower chamber 102 of the combustor regenerator vessel 50 'and preferably from the distributor across the entire cross section of the dense catalyst layer 58'. Is blown radially into its dense catalyst layer 58 '. The recycle gas derived from the catalyst distributor 110 helps to eject the catalyst from the catalyst distributor 110 into the bed and also provides oxygen for the combustion conditions. Header 66 and nozzle 68 of catalyst distributor 110 are configured as described with respect to FIGS.

In the lower chamber 102 the mixture of catalyst and combustion gas rises through the frustoconical transition section 116 to the riser section 118 of the transport of the lower chamber 102. The riser section defines the tube and extends upwardly from the lower chamber 102. The mixture of catalyst and gas is at a higher supercritical gas velocity than in the lower chamber 102 due to the reduced cross-sectional area of the vertical tube section 118 relative to the cross-sectional area of the lower chamber 102 below the transition section 116. Move. Thus, their supercritical gas velocities generally exceed 2.2 m / s (7 ft / s). Vertical tube section 118 has a lower catalyst density that is 80 kg / m ³ (5 lb / ft ³ ) or less.

The mixture of catalyst particles and flue gas enters the upper chamber 104 from the riser section 118. Substantially fully regenerated catalyst may be withdrawn from the top of the riser section 118, but an arrangement in which some regenerated catalyst is withdrawn from the lower chamber 102 is also contemplated. Inflow is performed through a separation device 120 that separates most regenerated catalyst from the flue gas. Initial separation of the catalyst as it exits the riser section 118 minimizes the catalyst loaded on the cyclone separators 122, 124 or other downstream apparatus used to essentially completely remove the catalyst particles from the flue gas, The overall equipment cost is reduced. In any embodiment, the catalyst and gas flowing up in the riser section 118 impinge on the top elliptical cap 126 of the riser section 118 and flow in reverse. The catalyst and gas are then discharged through the downwardly directed opening in the radial separation arm 128 of the separation device 120. Breakdown loss and downward flow reversal of momentum leads to more than 70% by weight of the heavier catalyst falling into the dense catalyst layer 59, with the lighter flue gas and traces of catalyst still entrained there Ascending upward in chamber 104. The separated catalyst falling down is collected in the dense catalyst layer 59. The catalyst density in the dense catalyst layer 59 is typically maintained within the range of 640 to 960 kg / m ³ (40 to 60 lb / ft ³ ).

Fluidized gas line 55d is delivered to dense catalyst bed 59 via fluidized distributor 131. The fluidizing gas may be combustion gas, typically air, and may be a branch derived from the combustion gas line 55. In the combustor regenerator vessel 50 ', complete combustion of the coke is carried out in the bottom chamber 102 and up to approximately 2% by weight of the total gas requirements in the process enters the dense catalyst bed 59 through the fluidization distributor 131. While the remainder is added to the lower chamber 102. In this embodiment, the gas is added to the upper chamber 104 for fluidization purposes, not for combustion purposes, so that the catalyst is fluidly discharged through the catalyst conduits 108 and 12. The combustion gas added via gas lines 55a 'and 55c' corresponds to 10-20% by weight of the gas leading to the combustor regenerator vessel 50 '. If the air is a combustion gas, typically between 13 and 15 kg of air are required per kg (lbs) of coke fed onto the catalyst leading to the regenerator. Combustor regenerator vessel 50 ′ typically has a temperature of 594 to 704 ° C. (1100 to 1300 ° F.) in lower chamber 102 and a temperature of 649 to 760 ° C. (1200 to 1400 ° F.) in upper chamber 104. Has The pressure in both chambers may be 173-414 kPa (gauge) (25-60 psig).

The combination of flu and fluidizing gas and entrained catalyst particles enters one or more separation means, such as cyclone separators 122 and 124, which separate the catalyst from the gas. The relatively catalyst free flue gas is withdrawn from the combustor regenerator vessel 50 'through the exhaust conduit 130, while the recovered catalyst is respectively dense catalyst layer 59 through the dip legs 132 and 134. Is returned to. The catalyst derived from the dense catalyst layer 59 is returned back to the reactor section 10 where the catalyst is in contact with the feed again as the FCC process continues.

FIG. 5 illustrates an embodiment in a regenerator vessel 50 ′ that is a two-stage bubbling bed regenerator, which may be suitable in an FCC unit that handles heavy feeds such as a resin unit. . Elements in FIG. 5 that have the same configuration as in FIG. 1 or 4 have the same reference numerals as in FIG. 1 or 4. In FIG. 5, which have different configurations than the corresponding elements in FIG. 1 or 4, the elements have the same reference numerals, but are denoted by double primes (“). In FIG. 5 the construction and operation of the reactor section 10 is basically The same as in 1, and the foregoing description is incorporated by reference in the embodiment of Fig. 5. A reactor catalyst conduit 48 "having an inlet 48a in downstream communication with reactor vessel 32 is a control valve 52 Feeds the coking catalyst to the regenerator riser 54 "at a rate controlled by the lift gas. The lift gas pushes the catalyst over the regenerator riser. When air or other oxygen-containing combustion gas is used as the lift gas, It can be added from a riser gas line 55 "branching from the combustion gas line 55". The reactor catalyst conduit 48 "is added to the catalyst distributor (" ") in the upper chamber 104" of the regenerator vessel 50 ". Outlet communicating with 60 ”) The fluidizing gas, which may be combustion gas, propels the coking catalyst through a catalyst distributor 60 ". In the embodiment of FIG. 5, the coking catalyst descends the reactor catalyst conduit 48 "to reach the bend in communication with the regenerator vertical tube 54". The coking catalyst is bent around its curve as it is lifted by lift gas derived from a gas line 55a "having an outlet in upstream communication with the regenerator riser 54". The coking catalyst then moves over the regenerator riser 54 "and enters the regenerator vessel 50" via the coking catalyst inlet 56 ". The coking catalyst is also characterized in that the two-stage generator is It is considered to be first introduced into the lower chamber of the two stage regenerator, if designed together. Catalyst distributor 60 having an inlet which can communicate downstream with the outlet from catalyst inlet 56 "and vertical gas line 55a". &Quot;) distributes the coking catalyst to the upper chamber 104 " of the regenerator vessel 50 ". In the embodiment of FIG. 5, the inlet for the catalyst distributor 60 ″ and the catalyst inlet for the regenerator vessel 50 ″ may be adjacent to each other. Regenerator riser 54 "may terminate at normal head portion 62. Regenerator riser 54" is located immediately upstream of catalyst dispenser 60 "and disposed below catalyst dispenser 60". A portion of the reactor catalyst conduit 48 ". The header 66 may include a longitudinal pipe that may be disposed below the top head 62. Additionally, the header 66 may include a regenerator vertical tube 54". Can be perpendicular to. The catalyst distributor 60 "includes one or more, preferably a plurality of nozzles 68 in communication with the header for discharging the catalyst into the upper chamber 104" of the regenerator vessel 50 ".

In any embodiment, the catalyst distributor 60 "discharges the coking catalyst below the top surface of the dense catalyst layer 58", and the catalyst distributor 60 "is within its dense catalyst layer below its top surface. In addition, the catalyst distributor 60 " is disposed in an eccentric position in the upper chamber 104 " of the regenerator vessel 50 " and from the distributor across the entire cross section of the dense catalyst bed. The catalyst is radially ejected into the dense catalyst layer 58 ". In the regenerator resin tube 54 the lift gas helps to eject the catalyst from the catalyst distributor 60 into the dense catalyst layer and also provides oxygen for combustion requirements. Header 66 and nozzle 68 of catalyst distributor 60 " are configured as described with respect to FIGS.

Oxygen-containing gas, typically air, derived from the combustion gas line branches 55d ", 55e" of the combustion gas line 55 "regulated by a control valve, each combustion gas under the catalyst distributor 60" Dispensers 200 and 202 are mainly distributed to the upper chamber 104 "of the regenerator vessel 50". In any embodiment, the combustion gas distributors 200, 202 distribute most of the combustion gas to the upper chamber. Oxygen in the combustion gas is contacted with the coking catalyst to burn most of the carbon deposits from the catalyst to regenerate the catalyst and generate flue gas. The catalyst may be entrained by the flue gas rising in the upper chamber 104 ". Therefore, the catalyst entrained in the flue gas enters the cyclone separators 122" and 124 ", thereby increasing the flue from heavier catalyst particles. The gas is centripetally separated. The catalyst particles fall into the deep legs 132 ″ and 134 ″ and flow back into the dense catalyst layer 58 ″. The cleaned flue gas rises from the cyclone distributors 122 "and 124" through the conduit into the plenum 90 "and exits through the flue gas outlet 130. Partially regenerated catalyst is sent to the control valve 106 The dense catalyst layer 58 "leaves the lower chamber 102" through the transport catalyst conduit 108 "regulated by it.

The hot partially regenerated catalyst enters the inlet of the recycle catalyst conduit 108 in downstream communication with the upper chamber 104 ". The outlet end of the transport catalyst conduit 108" is the catalyst distributor 110 in the lower chamber 102 ". ) And the high temperature partially regenerated catalyst enters the lower chamber 102 "via the second catalyst distributor 110. A predominantly upstream portion of the transport catalyst conduit 108 ″ is disposed above the catalyst distributor 110.

Catalyst distributor 110 having catalyst inlet 116 and inlet 114 in downstream communication with recycle gas line 55c ″ distributes the recycled regenerated catalyst to lower chamber 102 " of regenerator vessel 50 ". The inlet 114 is in communication with a header 66, which may include a longitudinal axis. Additionally, the header 66 may be angled directly upstream of the transport catalyst conduit 108 ". The catalyst distributor 110 includes one or more, preferably a plurality of nozzles 68 in communication with the header 66 for discharging the catalyst into the combustor lower chamber 102 "of the regenerator vessel 50". In any embodiment, the catalyst distributor 110 discharges coking catalyst below the top surface of the dense catalyst layer 58 ", and the catalyst distributor 110 is immersed in its seasoned catalyst layer below its top surface. In addition, the catalyst distributor 110 is disposed in an eccentric position in the regenerator vessel 50 "and crosses the catalyst from the distributor into the dense catalyst layer 58" across the entire cross section of the dense catalyst layer. Radially blows in. The gas derived from recycle gas line 55c 'helps eject the catalyst from catalyst distributor 110 into its dense catalyst bed and may also provide oxygen for combustion requirements. Header 66 and nozzle 68 of 110 are configured as in Figures 1-3. Catalyst distributor 110 and catalyst distributor 60 "are on opposite sides of regenerator vessel 50". May exist in

The combustion gas distributor 80 "supplied by the distributor gas line 55b" branched from the combustor gas line 55 "distributes most of the combustion gas to the lower chamber 102". In the combustion gas distributor 80 ", the flue gas 82 is arranged to evenly discharge the combustion gas to the entire cross section of the lower chamber 102" of the regenerator vessel 50 ". Oxygen in the combustion gas is coking catalyst To regenerate the catalyst and generate flue gas by burning most residual carbon deposits from the catalyst. The catalyst may be entrained in the flue gas and rise in the lower chamber 102 "and through the vent 204 May be discharged into the upper chamber 104 ". Partially regenerated catalyst entering the lower chamber 102" is completely regenerated by any combustion gas derived from the catalyst distributor 110 and the combustion gas distributor 80 ". Can be.

The outlet from the regenerated catalyst outlet 96 "and the lower chamber 102" of the regenerator vessel 50 "discharges the complete regenerated catalyst through the regenerated catalyst conduit 12". The regenerated catalyst conduit 12 "in downstream communication with the outlet 96" delivers the regenerated catalyst back to the reactor riser 20 at a rate controlled by the control valve 14.

Combustion gases, such as air, can be used to lift the coking catalyst over regenerator riser 54 ", which can generate regeneration in the regenerator riser. Combustion gas for regenerator riser 54 may be regenerated vessel 50 Can be 10-20% by weight of the combustion gas, if air is the combustion gas, typically air per kg (lb) of coke supplied on the catalyst to the regenerator vessel 50 "in the upper chamber 102". 11-13 kg (lbs) are required. 75 weight percent of all combustion gas requirements are supplied to the upper chamber 104 ". 6-11% by weight from the lower chamber 102 "enters the upper chamber 104" through the vent 204, with 25% by weight of all combustion gas requirements supplied to the lower chamber 102 ". Regenerator vessel 50 "typically has a temperature of 594-760 [deg.] C. (1100-1400 [deg.] F.) in both lower chamber 102 " and upper chamber 104 ". In both chambers, the supercritical velocity of the combustion gases is typically 1.2 m / s (4.2 ft / s) or less, and the density of the dense catalyst bed is typically 320 kg / m ³ (20 lb / ft ³⁾ , depending on the nature of the catalyst. ) In both chambers, the pressure may be 173 to 414 kPa (gauge) (25 to 60 psig).

5, the reactor catalyst conduit 48 "is disposed in the reactor catalyst conduit 48" as in FIGS. 1 and 4 except that the reactor catalyst conduit 48 "is disposed at a higher altitude in the upper chamber 104". It provides a reactor section 10 that can be disposed at the lower relative height while maintaining a similar downward angle with respect to

Catalyst distributors 60, 60 ', 60 "and 110 are supported by the ends of the catalyst conduits that are in proactive communication with them. Catalyst distributors 60, 110 are typically stainless steel, such as stainless steel 304. It is coated with a wear resistant lining on both the outside and inside The regenerator may be equipped with one or more catalytic coolers to avoid excessive high temperature regenerator temperatures.

Example  One

The catalyst distributor of the present invention was tested in an FCC regenerator by injecting radioactive sodium-24 liquid at various locations and monitored the progress through the catalyst bed of the regenerator. The sodium isotope was introduced into the regenerator in water soluble form. Once injected, the liquid component was flashed due to the high temperature process temperature, which attached sodium isotopes to the catalyst. The catalyst distribution and flow characteristics were monitored through the detector around the circumference of the regenerator vessel.

6 shows the distribution characteristics of the catalyst in the regenerator in the form of a radar plot. The catalyst distributor was placed at only 240 degrees in the direction of the radial line of the radial line. The catalyst outlet was placed between the center and the outer wall of the regenerator vessel on a radial line at 40 °. Actual catalyst distribution data is shown in smaller diamondoids. The ideal catalyst distribution profile is shown in larger squares for comparison. Scale percentages indicated the relative flow of spent catalyst relative to the specific detector location.

The detector ring showed an ideal distribution-like response around the circumference of the regenerator vessel. As a result, the catalyst distributor of the present invention provided superior catalyst distribution compared to the ideal distribution profile when the catalyst was unevenly exposed to the combustion gas.

Example  2

We compared the actual performance of the FCC regenerator before and after installation of the spent catalyst distributor of the present invention. Regenerator conditions remained the same, with the exception that less CO promoter was used for the catalyst after installation of the catalyst distributor.

The inventors have found that the largest temperature difference across the diameter of the regenerator vessel has decreased from 38 ° C. (100 ° F.) to 4 ° C. (40 ° F.) as a result of installing the catalyst distributor of the present invention. This indicates that less afterburning occurred due to the improved spent catalyst distributor in the regenerator. Similarly, the inventors have found that nitrogen oxide emissions in the flue gas have also been reduced from 80 wppm to 35 wppm after installation of the catalyst distributor of the present invention due to improved catalyst distribution.

Claims (10)

A catalyst regenerator vessel for burning carbon deposits from a catalyst,
A catalyst inlet for supplying a catalyst to the vessel,
A combustion gas line for introducing combustion gas into the vessel,
A catalyst distributor in communication with the catalyst inlet for dispensing the coking catalyst in the vessel, the catalyst distributor including a header having a longitudinal axis and an angular nozzle in communication with the header; Wherein the nozzle defines an acute angle with the longitudinal axis, the nozzle discharging the catalyst into the vessel,
A separator in communication with the regenerator vessel for separating gas from the catalyst,
A flue gas outlet for discharging flue gas from the vessel, and
Regenerated catalyst outlet for discharging regenerated catalyst from the vessel
Catalyst regenerator vessel comprising a. The catalyst regenerator vessel of claim 1 wherein the bottom of the nozzle is disposed at a quarter bottom of the header. The catalyst regenerator vessel of claim 1 wherein the longitudinal axis passing through the nozzle is horizontal. The catalyst regenerator vessel of claim 1 further comprising a plurality of nozzles in communication with the header defining an acute angle with the longitudinal axis, wherein the nozzle discharges catalyst into the vessel. The catalyst regenerator vessel of claim 1 further comprising a proximate nozzzle perpendicular to said longitudinal axis. The catalyst regenerator vessel of claim 1 comprising a distal nozzle aligned with the longitudinal axis. The catalyst regenerator vessel of claim 1 comprising two angled nozzles defining two different angles with said longitudinal axis. The nozzle of claim 1, comprising a plurality of nozzles and the angled nozzle, wherein the header has an inlet and outlet end, the nozzle being continuous as the nozzle is located further away from the inlet and closer to the outlet end. Defining a smallest angle with the longitudinal axis that decreases to. As a method of burning coke from a catalyst,
Delivering the coking catalyst to a catalyst distributor having a header defining a longitudinal axis,
Discharging the catalyst from the catalyst distributor into the regenerator vessel at an acute angle with the longitudinal axis,
Delivering combustion gas to the regenerator vessel to combust coke from the catalyst to produce flue gas and regenerated catalyst,
Separating the flue gas from the regenerated gas,
Draining the regenerated catalyst from the regenerator vessel, and
Draining flue gas from the regenerator vessel
How to include. The method of claim 9, wherein the catalyst distributor discharges the catalyst below the top surface of the catalyst bed.

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