KR20130025384A - Process and apparatus for increasing weight of olefins - Google Patents

Abstract

Processes and apparatus are provided for converting FCC olefins to heavier compounds. The heavy compound is more easily separated from unreacted paraffin. Heavy compounds can be recycled to the FCC unit or shipped to a separate FCC unit. Suitable conversion zones are oligomerization and aromatic alkylation zones.

Description

PROCESS AND APPARATUS FOR INCREASING WEIGHT OF OLEFINS}

A claim of priority

This application claims priority to US Application 12 / 751,623 and US Application 12 / 751,658, filed March 31, 2010.

Field of technology

The present invention relates to a process and apparatus for converting olefins mixed with paraffins to higher molecular weight compounds which are readily separated from unconverted paraffins.

Fluid catalytic cracking (FCC) is a catalytic hydrocarbon conversion process achieved by contacting a heavier hydrocarbon with catalytic particulate material in a fluidization reaction zone. Unlike hydrocracking, catalytic cracking reactions are carried out in the absence of hydrogen or in the absence of significant amounts of hydrogen. As the decomposition reaction proceeds, a significant amount of high carbonaceous material (called coke) is deposited on the catalyst to produce coking or spent spent catalyst. The vapor lighter product is separated from the spent catalyst in the reactor vessel. The spent catalyst is stripped under an inert gas such as steam, thus allowing the trapped hydrocarbonaceous gas to be stripped from the spent catalyst. The high temperature regeneration operation with oxygen in the regeneration zone burns coke from the waste catalyst (pre stripped). From this process various products (including gasoline products and / or light products such as propylene and / or ethylene) can be obtained.

In this process, a single reactor or dual reactors can be used. Although additional capital expense may be incurred by using a dual reactor apparatus, one reactor may be operated at custom conditions to maximize products such as light olefins (including propylene and / or ethylene).

It may be efficient to maximize the yield of the product of one reactor. In addition, there may be a need to maximize the production of product from one reactor that can be recycled to another reactor to produce the desired product, such as propylene.

The decomposition of C ₄ -C ₇ olefins yields high yields of propylene. Recycling the C ₄ -C ₇ -rich stream to the FCC reactor can be used to further increase the production of propylene. However, this recycling leads to the concentration of refractory paraffins in the recycle stream and requires an effective clarification or high recycle flow rate. There is no simple way to separate olefins from paraffins in a wide range of breakpoints.

Oligomerization of olefins on heterogeneous catalysts with heavy olefins for automotive fuels is a known technique. Also known are techniques for alkylating olefins with paraffins on homogeneous acid catalysts to make automotive fuels. It is also known to alkylate benzene and other aromatic components and olefins typically on heterogeneous catalysts to make petrochemical feedstocks comprising detergent precursors.

There is a need to easily separate olefins from paraffins in the product stream.

Summary of the Invention

In one exemplary embodiment, the present invention involves the process of converting olefins to heavy compounds. C ₄ olefins and paraffins and C ₅ - C ₇ olefins and passed through a paraffin in a conversion zone aromatic and C ₅ - by alkylation of C ₇ olefins, C ₅ - C ₇ a greater C ₅ olefins molecular weight - C _7-derived compound And C ₄ olefins to C ₄ derived compounds having higher molecular weight. C ₄ derived compounds are separated from C ₄ olefins and paraffins, and C ₅ -C ₇ derived compounds are separated from C ₅ -C ₇ olefins and paraffins. Finally, C ₄ derived compounds and C ₅ -C ₇ derived compounds are fed to the FCC reactor.

In further exemplary embodiments, the present invention involves the process of converting olefins to heavy compounds. C ₅ - C ₇ is converted to the compound derived from - C ₇ olefins and by passing a first stream of the paraffin in the first zone C ₅ - C ₇ a larger molecular weight C ₅ olefins. A second stream of C ₄ olefins and paraffins is passed through the second zone to convert the C ₄ olefins to higher molecular weight C ₄ derived compounds. C ₄ derived compounds are separated from C ₄ olefins and paraffins, and C ₅ -C ₇ derived compounds are separated from C ₅ -C ₇ olefins and paraffins. Finally, C ₄ derived compounds and C ₅ -C ₇ derived compounds are fed to the FCC reactor.

In further exemplary embodiments, the present invention involves the process of converting olefins to heavy compounds.

The cracking catalyst is contacted with the hydrocarbon stream to crack the hydrocarbon into cracked product hydrocarbons with low molecular weight and accumulate coke on the cracking catalyst to provide a caulked cracking catalyst. The coked cracking catalyst is separated from the cracked product. Coke on the coked cracking catalyst is burned with oxygen to regenerate the cracking catalyst. The cracked product is separated in the main fractionation column. At least a portion of the overhead stream from the fractional column is compressed to provide a compressed overhead stream. The liquid stream is separated from the compressed overhead stream and at least some of the liquid stream is depropaneized to provide a C ₄ -C ₇ stream of paraffins and olefins. C ₄ - C ₇ stream of olefins and paraffins C ₄ - is supplied to the switch to be switched to C _7-derived compounds zone - C ₇ a larger molecular weight C ₄ olefins.

In one embodiment, the present invention includes a device for converting an olefin into a higher molecular weight compound to make an FCC feed. The apparatus includes a process fractionation column for separating an overhead stream comprising a C ₃ -rich overhead stream from a C ₅ -rich bottoms stream. The aromatic alkylation reactor communicates with the bottom line of the process fractionation column to alkylate the aromatics and olefins in the C ₅ -rich bottoms stream. The product column is in communication with the aromatic alkylation reactor to separate the alkylaromatics from the unreacted compound from the C ₅ -rich bottoms stream. Finally, the FCC reactor is in communication with the bottom line of the product column.

In a further embodiment, the present invention includes an apparatus for converting olefins to heavy compounds to make FCC feeds. The apparatus includes a process fractionation column for separating an overhead stream comprising a C ₃ -rich overhead stream from a C ₅ -rich bottoms stream. The first conversion zone communicates with the bottom line of the process fractionation column to convert C ₅ -C ₇ olefins to higher molecular weight C ₅ -C ₇ derived compounds. The second conversion zone communicates with the overhead line of the process fractionation column to convert C ₄ olefins to higher molecular weight C ₄ derived compounds. The product splitter column is in communication with the first conversion zone to separate the C ₅ -C ₇ derived compound from the unreacted compound. Finally, the FCC reactor communicates with the bottom line of the product splitter column.

In a further embodiment, the present invention includes a device for converting FCC olefins to heavy compounds. The apparatus includes a fluid catalytic cracking reactor comprising a cracking catalyst that is contacted with a hydrocarbon stream to crack the hydrocarbon into a cracked product hydrocarbon having a low molecular weight and accumulate coke on the cracking catalyst. The catalyst regenerator burns the coke on the coked cracking catalyst with oxygen to regenerate the cracking catalyst. The main fractionation column is in communication with a fluid catalytic cracking reactor to separate the cracked product. The compressor communicates with the overhead line of the fractional column to compress at least a portion of the overhead stream from the fractional column. The receiver is in communication with the compressor to separate the liquid stream from the compressed overhead stream. The process fractionation column is in communication with a receiver for depropaneizing at least a portion of the liquid stream. The conversion zone communicates with the process fractionation column to convert C ₄ -C ₇ olefins to higher molecular weight C ₄ -C ₇ derived compounds.

Additional features and effects of the present invention will appear in the description, the drawings, and the claims.

1 is a schematic representation of an FCC unit and an FCC product recovery zone.
2 is a schematic representation of an alternative FCC unit and FCC product recovery zone.
3 is a schematic diagram of a further alternative FCC unit and FCC product recovery zone.
4 is a schematic of an oligomerization conversion zone.
5 is an alternative schematic of an aromatic alkylation conversion zone.

Justice

The term "communication" means that the material flow is operatively made between the listed components.

The term "downstream communication" means that at least a portion of the material flowing from the subject in the downstream stream can operatively flow to the communicating object.

The term "upstream communication" means that at least a portion of the material flowing from the subject in the upstream stream can be operatively flowed to the communicating object.

The term "column" means a distillation column or columns for separating one or more different volatile components that may have a reboiler at the bottom and a condenser at the top. Unless otherwise specified, each column has a condenser disposed at the top of the column to condense a portion of the overhead stream to the top of the column, and a column bottom to evaporate a portion of the bottom stream back to the column bottom. It has a reboiler disposed in. The feed to the column may be preheated. The upper pressure is the overhead vapor pressure at the outlet of the column. The bottom temperature is the temperature of the liquid bottom outlet. The top line and the bottom line refer to the net line from the bottom stream column to the column of reflux or reheat.

As used herein, "rich-rich stream" means that the stream exiting the separation vessel has a greater concentration of its components than the feed fed to the separation vessel.

As used herein, “lean stream” means that the stream exiting the separation vessel has a lower concentration of its constituents than the feed fed to the separation vessel.

DETAILED DESCRIPTION OF THE INVENTION

A simple process has been devised that separates olefins from paraffins from an FCC product stream comprising C ₄ and heavy products, preferably C ₄ -C ₇ products, and recycles the olefins to the main FCC reactor or a separate FCC reactor. The FCC product recovery zone may have one main fractionation column and one gas plant. The present invention includes reaction zones in which olefins are converted to different species that can be easily separated from inert paraffins. The converted and separated olefin derived products can be recycled back to the main FCC reactor or a separate FCC reactor.

Referring to FIG. 1, where like reference numerals designate like components, FIG. 1 generally shows a refining composite 6 comprising an FCC unit zone 10 and a product recovery zone 90. The FCC unit section 10 includes a reactor 12 and a catalyst regenerator 14. Modifications of the process typically include decomposition reaction temperatures of 400 ° C. to 600 ° C. and catalyst regeneration temperatures of 500 ° C. to 900 ° C. Both cutting and regeneration takes place below absolute pressure 506 kPa (72.5 psia).

1 shows a conventional FCC reactor 12 in which a crude oil stream or heavy hydrocarbon feed from distributor 16 is contacted with a regenerated cracking catalyst coming from regenerated catalyst standpipe 18. The contact may occur in a narrow riser 20 extending upwards from the bottom of the reaction vessel 22. Contact of the feed with the catalyst is fluidized by gas from fluidization line 24. In one embodiment, the heat from the catalyst evaporates the hydrocarbon feed or oil, which is then conveyed through the reaction vessel 22 to the riser 20, so that the hydrocarbon feed is light in the presence of the catalyst. Decomposes into hydrocarbon products. Unavoidable side reactions occur in riser 20 that produce coke accumulated on catalysts of low catalytic activity. The cracked light hydrocarbon product is then separated from the coked cracking catalyst using a circulating separator comprising one or two stages of circulator 28 and first separator 26 in the reaction vessel 22. The gaseous cracked product is discharged from the reaction vessel 22 to the line 32 via the product outlet 31 to the downstream product recovery zone 90. Spent or caulked catalyst requires regeneration for further use. The coked cracking catalyst separated from the gaseous product hydrocarbons enters stripping zone 34 where the stream is injected through a nozzle to purge residual hydrocarbon vapors. After the stripping process, the caulked catalyst is transferred to the catalyst regenerator 14 through spent catalyst catalyst standpipe 36. An optional spent catalyst pipe 56 carries the spent catalyst from the stripping zone 34 at a rate controlled by the regulating valve to the riser reactor 12 through the spent catalyst inlet.

Figure 1 shows a catalyst regenerator 14 known as a combustor. However, other types of players are also appropriate. In the catalyst regenerator 14, a gas stream comprising oxygen, such as air, is introduced to contact the coked catalyst through the air distributor 38. Coke is burned from the coked catalyst to provide regenerated catalyst and flue gas. In order to provide energy for the endothermic cracking reaction that occurs in the riser reactor 20, a catalytic amount of heat is applied to the catalyst in the catalyst regeneration process. Along the combustor riser 40 disposed in the catalyst regenerator 14, the catalyst and air flow together upwards, and after regeneration are initially separated by filling through the termination device 42. Further recovery of the regenerated catalyst and flue gas exiting the termination device 42 is achieved by using first and second stage separator cyclones 44, 46 disposed in the catalyst regenerator 14, respectively. While the relatively light flue gas in the catalyst is sequentially discharged from the cyclones 44 and 46, the catalyst separated from the flue gas is distributed through the deep legs in the cyclones 44 and 46 and in the flue gas line 48. It is discharged from the regeneration vessel 14 through the flue gas outlet 47. The regenerated catalyst is transported to the riser 20 through the regenerated catalyst catalyst standpipe 18. As a result of the coke burning, the flue gas vapor exiting the catalyst regenerator 14 in line 48 contains CO, CO ₂ , N ₂ and H ₂ O together with other small amounts. The hot flue gas exits the catalyst regenerator 14 through flue gas outlet 47 in line 48 for further processing.

The FCC product recovery zone 90 communicates downstream with the product outlet 31 via line 32. In product recovery zone 90, the gaseous FCC product in line 32 is in direct communication with the lower zone of FCC main fractionation column 92. The main fractionation column 92 also communicates downstream with the product outlet 31. Multiple fractions of FCC product are from the heavy naphtha stream in line 96, light cycle oil (LCO) in line 95 taken from outlet 95a, heavy cycle oil in line 94 Oil, HCO) stream, may be taken separately from the main column containing heavy slurry oil from the bottoms in line 93. Any or all of the streams in lines 93-96 may be cooled and pumped back to the main fractionation column 92, typically to cool the main column at a higher position. Gasoline and gaseous light hydrocarbons are removed from the main fractionation column 92 above line 97 and condensed before entering the main column receiver 99. The main column receiver 99 is in downstream communication with the product outlet 31.

The aqueous stream is removed from the boot in the receiver 99. In addition, the hard naphtha stream condensed while the overhead stream is removed in line 102 is also removed in the bottom of line 101. A portion of line 101 is again refluxed near the top of main fractionation column 92, which is in communication with main column receiver 99 in the upstream stream. The overhead stream of line 102 contains a gaseous light hydrocarbon that may comprise a diluted ethylene stream. Streams of lines 101 and 102 enter gas recovery zone 120 of product recovery zone 90.

Although gas recovery zone 120 is shown to be an absorption based system, any gas recovery system can be used, including a cold box system. In order to sufficiently separate the light gas components, the gaseous stream of line 102 is condensed in condenser 104. One or more compression stages may be used, and in order to produce a condensed first FCC product stream, the gaseous overhead stream of line 102 may vary from 1.2 MPa to 3.4 MPa (gauge) (180-500 psig). Condensation, typically double stage condensation and appropriate triple stage condensation are used.

The condensed light vapor hydrocarbon stream in line 106 may be joined with the streams in lines 107 and 108, cooled and sent to high pressure receiver 110. The aqueous stream from the receiver 110 goes to the main column receiver 99. In the high pressure receiver, the stream on the condensed vapor in the overhead line 112 is separated from the liquid stream in the bottom line 124. From the overhead of the high pressure receiver 110, the gaseous hydrocarbon stream of the line 112 proceeds to the end of the lower first absorption column 114. In the first absorption column 114, the gaseous hydrocarbon stream is in communication with the main column receiver 99 (the upper end of the first absorption column 114) of the C ₃ + hydrocarbons and C ₂ -hydrocarbons in the bottom of the line 101. Contact with unstable gasoline), which causes separation. The separation is further enhanced by supplying stable gasoline from line 35 to the supply point of the bottom line 101. The first absorption column 114 communicates downstream with the overhead line 102 of the main column receiver via the bottom line 101 and the lines 106, 112 of the main column receiver 99. Liquid in line 107 ₃ + C-rich bottom stream prior to cooling, returned to the line 106. The first off gas stream of line 116 from the first absorption column 114 is in direct communication with the low end of the second absorption column 118. The second absorption column is in downstream communication with the first absorption column 114. The LCO circulating stream in line 121, which is redirected from line 95 to the second absorption column 118, is the most of the C ₅ + material and some C ₃ -C ₄ Absorb the substance. The second absorption column 118 is in downstream communication with the main fractionation column 92 and the first absorption column 114. The L ₃ rich in C 3+ material from the second absorption column in the bottom line 119 is returned to the main fractionation column 92 via a circulating pump-around for line 95. The main fractionation column 92 communicates downstream with the second absorption column via the bottom line 119. The overhead of the second absorption column 118 comprising a dry gas consisting mainly of C ₂ -hydrocarbons with hydrogen sulfide, ammonia, carbon dioxide and hydrogen can be removed in the second offgas stream of line 122, the process May proceed further. Both absorption columns 114, 118 do not have a condenser or reboiler, but a circulating reflux circuit can be applied.

Liquid from the high pressure receiver in line 124 is sent to stripper column 126 for fractionation. The stripper column 126 is in downstream communication with the receiver 110 via the bottom line 124. Most of C ₂ − is removed within the overhead of stripper column 126 and returned to line 106 via overhead line 108. In one aspect, the liquid bottoms stream from the stripper column 126 is sent to the fractionation column 13 process via line 128. Stripper column 126 does not have a condenser, but receives a cooled liquid feed from line 124.

Process fractionation column 130 separates the C ₃ -rich overhead stream of line 132 from the C _5- , C ₆ -and / or C ₇ -rich bottom streams of line 134. The overhead stream in the overhead line 132 coming from the process fractionation column 130 is C ₃ Olefins and paraffins, preferably C ₃ and C ₄ Olefins and paraffins. The bottoms stream in the bottom line 134 is C ₅ olefins and paraffins, preferably C _{5 ,} C ₆ and / or C ₇ (indicated here as C ₅ -C ₇ olefins and paraffins). Olefins and paraffins. In addition, the bottoms stream in line 134 contains heavy naphtha components as well as C ₅ + naphthenes and C ₆ + aromatics.

In order to make light olefins further, C ₄ -C ₇ olefins are sent to the FCC reactor 12 or to a separate FCC reactor (not shown). However, recycling the C ₄ -C ₇ streams of paraffins and olefins to the FCC reactor 12 results in the formation of inert paraffins. It is difficult to separate paraffins from all carbon number olefins in the naphtha range. The present invention proposes a process for converting an olefin to a heavy compound so that the olefin can be easily separated from the unconverted light paraffin.

In one embodiment, a mixed stream of C ₃ and / or C ₄ olefins and paraffins in overhead line 132 may be sent to LPG splitter column 140. LPG splitter column 140 communicates downstream with overhead line 132 of process fractionation column 130. A stream of separated C ₃ olefins and paraffins in overhead line 142 of LPG splitter column 140 may be subjected to additional processing to recover propylene. The bottoms stream of C ₄ olefins and paraffins may be separated in the bottoms line 144.

Bottom line 134 in a portion of the stabilized gasoline is line 135 in can be recycled to the top (top) of the first absorption column above the injection point of the line (101, 112) in order to improve the recovery of C ₃ + have. In one embodiment, the net bottoms stream 136 from the debutulization column may be fractionated in the naphtha splitter column 150. C ₆ +, C ₇ + or more, preferably C ₈ + heavy naphtha streams may be recovered in the bottom line 152 for further processing and / or storage. In addition to naphthenes and aromatics, an overhead stream comprising C ₅ , C ₅ -C ₆ or more, preferably C ₅ -C ₇ olefins and paraffins, is provided in line 154.

In one embodiment, C ₅ -C ₇ The overhead stream 154 comprising olefins C ₅ -C _{7 in} downstream communication with overhead line 154 of naphtha splitter column 150 and bottom line 134 of process fractionation column 130. It may be supplied to a first diverting zone 160, which may include a diverting zone. Any, some or all of the C ₅ -C ₇ olefins can be converted to higher C ₅ -C ₇ -derived compounds in the first conversion zone. Suitable reactions that may be performed in the first conversion zone 160 may include oligomerization or aromatic alkylation. The first product, which may include C ₅ -C ₇ -derived products, exits the first conversion zone in line 162.

The bottoms stream of C ₄ olefins and paraffins in the bottoms line 144 communicates downstream with the overheads line 132 of the LPG splitter column 140 and the overhead lines 132 of the process fractionation column 130. Shipped at 170. The second diverting zone may be a C ₄ diverting zone. C ₄ olefins can be converted to higher molecular weight C ₄ -derived compounds in the second conversion zone. Suitable reactions that may be performed in the second conversion zone 170 may include oligomerization or aromatic alkylation. The second product, which may include the C ₄ -derived product, exits the first conversion zone in line 172. The same process or different processes may be performed in each of the first and second transition zones 160, 170. In FIG. 1, the first diverting effluent in line 162 joins the second diverting effluent in line 172 and enters stabilization column 180. The two lines 162 and 172 may be separated or joined to enter the stabilization column 180. Additionally, where steam may enter the column 180 of the liquid feed, which may or may not be injected into line 162, the stream in line 172 may be cooled and separated. The stabilization column 180 may be in downstream communication with the first and second transition zones 160, 170.

Three streams can be fractionated and removed from the stabilization column 180. The overhead gas stream in line 182 that includes C ₃ -material that can be recovered enters the gas plant or is sent to fuel gas. The side cut stream of C ₄ paraffin in line 184 may be recovered or subjected to further processing in the LPG treatment zone or oligomerization zone (described herein). The bottoms stream in line 186 containing heavy C ₄ and C ₅ -C ₇ derived compounds proceeds to product splitter column 190.

The product splitter column is in downstream communication with the bottom line 186 from each of the first and second conversion zones 160, 170 and stabilization column 180, which are oligomerization or alkylation reactors. Alternatively, line 162 may not enter stabilization column 180, but bypasses product splitter column 190 when line 172 enters the stabilization column separately. The product splitter column can provide two streams. C ₅ -C ₇ in line 192 withdrawn for further processing Overhead streams containing unconverted material may be recovered for use in alkylation processes, described below, or for further treatment in a naphtha hydrotreater, such as via a gasoline pool, to remove sulfur. Can be. Some or all of the bottoms stream in line 194 comprising higher molecular weight C ₄ and C ₅ -C ₇ derived compounds such as alkylaromatics or oligomers may be recycled to the feed of FCC reactor 12. Although a recycle stream in line 194 enters line 16 with the first feed, it may enter riser 20 at another location. According to one aspect, the FCC reactor 12 communicates downstream with the bottom line 194 of the product splitter 190. The bottom fraction in line 194 may be returned to the FCC reactor 12 or to a different FCC reactor for further decomposition to improve the yield of light olefins.

2 shows an alternative embodiment to FIG. 1. In FIG. 2, only one transition zone 160 ′ is shown. Components which are different from the components of FIG. 1 but which are shown in corresponding FIG. 2 are indicated by reference numerals together with the prime sign '. All other components of FIG. 2 are identical to FIG. 1.

In one aspect, the liquid bottoms stream in line 128 from stripper column 126 that includes a portion of the liquid stream in bottoms line 124 is sent to process fractionation column 130 ′. Process fractionation column 130 ′ communicates downstream with stripping column 126 via bottom line 128. Process fractionation column 130 ′ may include a depropanification column that separates the C ₃ -rich overhead stream in line 132 from the C ₄ -rich and / or C ₅ -rich bottoms stream in line 134 ′. Can be. The bottoms stream in line 134 '(including olefins and paraffins, referred to herein as C ₄ -C ₇ streams) C _{4 ,} C _{5 ,} C ₆ And / or C ₇ , while the overhead stream in line 132 ′ from the process fractionation column may comprise a C ₃ product comprising olefins and paraffins. In addition, the bottoms stream in line 134 ′ may include heavy naphtha components as well as C ₅ + naphthenes and C ₆ + aromatics.

A portion of naphtha in a bottom line 134 'may be recycled in line 135 to the first absorption column above the injection point of the line (101, 112) to enhance the recovery of C ₃ +. In one embodiment, the net bottoms stream 136 from the depropaneation column may be fractionated in the naphtha splitter column 15. C ₅ +, C ₆ +, C ₇ + or preferably C ₈ + heavy naphtha streams may be recovered in the bottom line 152 for further processing and / or storage. An overhead stream comprising naphthenes and aromatics, as well as C ₄ , C ₄ -C ₅ , C ₄ -C ₆ or more, preferably C ₄ -C ₇ olefins and paraffins, is provided in line 154 '. do.

In one embodiment, overhead stream 154 ′ is downstream in communication with bottom line 134 ′ of process fractionation column 130 ′ and may comprise a first divert zone 160 that may include a C ₄ -C ₇ diverge zone. ') Can be supplied. Any, some or all of the C ₄ -C ₇ olefins can be converted to higher C ₄ -C ₇ derived compounds in the first conversion zone. Suitable reactions that may be performed in the first conversion zone 160 ′ may include oligomerization or aromatic alkylation. The first product, which may include the C ₄ -C ₇ -derived product, is discharged in the first conversion zone in line 162 ′ and enters stabilization column 180. And, as in FIG. 1, proceeds to the C ₄ -C ₇ -derived product in the FCC reactor.

3 shows an alternative embodiment of FIGS. 1 and 2. In FIG. 3, only one transition zone 160 ″ is shown. Components different from those of FIG. 1 but corresponding to those shown in FIG. 3 are indicated by reference numerals together with the prime sign ''. All other components of FIG. 3 are identical to FIG. 1.

The bottoms stream of C ₄ olefins and paraffins in the bottoms line 144 '' is the bottoms line 144 '' of the LPG splitter column 140 '', the overhead line 132 of the process fractionation column 130, the process fractionation The first transition zone 160 ″ is communicated downstream with the bottom line 134 of column 130 and the overhead line 154 ″ of naphtha splitter column 150. The bottom line 144 ″ may join or separate the overhead line 154 ″ and enter the first diverting zone 160 ″.

A first switching section (160 '') has a first switch that has any, some or all of the C ₄ -C ₇ olefin having a molecular weight in the zone can be converted to the more C ₄ -C ₇ derived from compound C ₄ -C ₇ And a diverting zone. Suitable reactions that may be performed in the first conversion zone 160 ″ may include oligomerization or aromatic alkylation. The first product, which may include the C ₄ -C ₇ -derived product, is discharged in the first conversion zone in line 162 ″ and enters stabilization column 180. And, as in FIG. 1, proceeds to the C ₄ -C ₇ -derived product in the FCC reactor.

The first and / or second conversion zone may comprise the oligomerization reactor 200 illustrated in FIG. 4. The oligomerization reactor 200 may be in downstream communication with the bottom lines 144, 144 ″ of the LPG splitter color 140 of FIGS. 1 and 3. The same or separated oligomerization reactor 200 is the bottom line 134, 134 ′ from the process fractionation column 130 and / or the overhead lines 154, 154 ′ of the naphtha splitter column 150 of FIGS. 1 and 2. ) And downstream communication. In one embodiment, the diolefin in the bottoms stream in lines 144, 144 ″, 154 or 154 ′ undergoes a first reaction with an optional hydrogenation catalyst in the selective hydrogenation zone 206 to not fully saturate with paraffin. And optionally into line 202 to be a saturated diolefin. Suitable conditions for operating the selective hydrogenation process are described, for example, in US Pat. No. 6,166,279 and US Pat. No. 6,075,173. Deposited on a support such as aluminum oxide at a temperature of 20 ° C. to 200 ° C. (68 ° F. to 392 ° F.), a pressure of 689 to 3447 kPa (g) (100 to 500 psig) and a space velocity of 0.5 to 10 hr ⁻¹ . A liquid olefin and paraffin stream in line 202 selected from the group formed from nickel, palladium and platinum formed and comprising at least one metal, and hydrogen in line 208 between 0.5 and 5 (moles of hydrogen / Diolefin moles) such conditions, passing in a molar ratio. Although only one is shown, two or more reaction zones may be used. Each reaction zone may apply recycle of reactor effluent (not shown) to the reactor inlet at a recycle rate of 0 to 20 for the fresh olefination feed stream. The diolefin residue of the process may range from 1 to 100 wppm, depending on the degree of operation.

With diolefins less condensed than line 202, the output from the selective hydrogenation reactor in line 210 (recycle stream effluent in line 216, optional variant in line 214, of FIG. 1 or 2). May be mixed with one, some, or all of the paraffinization dilution in line 212, which may be part of the paraffinization stream in line 184, and then in the oligomerization reactor in line 218 Supplied to 200. In the oligomerization reactor 200, the C ₄ olefins of line 144, the C ₅ -C ₇ olefins of line 154, or the C ₄ -C ₇ olefins of line 154 'or 154''are either oligomerization catalysts. And oligomerization conditions for the production of heavy olefins. The oligomerization reactor is shown as a downstream reactor, but upstream reactors may also be applied.

The operating conditions of the oligomerization process can be catalyzed by olefins and liquids (e.g. SPA) or sulfonated exchange resins (e.g. Amberlyst A-15, A-35, A-16, A-36, Dowex 50 or similar). Pass through onto a fixed layer). Other devices can be used to limit the formation of heavy oligomers. These are the addition of paraffinized dilution of line 212 to the oligomerization reactor when recycling SPA catalyst, recycling of part of the oligomerization reactor effluent of line 216 to oligomerization reactor 200 and when the resin catalyst is used. , Addition of 0.1 to 3.0 mass% of the selective modification in line 214 to the oligomerization reactor. Avoiding the production of heavy olefins is not critical. Thus, one or all streams in lines 212-216 can be omitted.

Preferred operating conditions apply differently when using an SPA catalyst and when using an exchange resin catalyst. When using an SPA catalyst, the preferred temperature is 40 ° C. to 260 ° C., more typically 75 ° C. to 230 ° C., while using an ion exchange resin catalyst, the preferred temperature is 0 ° C. to 200 ° C., more typically 40 ° C. To 150 ° C. When using an SPA catalyst, the preferred pressure is 689 to 8274 kPa (g) (100 to 1200 psig), more typically 1379 to 6895 kPa (g) (200 to 1000 psig), while using an ion exchange resin catalyst In this case, the preferred pressure is 345 to 3447 kPa (g) (50 to 500 psig), more typically 1379 to 2413 kPa (g) (200 to 350 psig). This pressure can be kept below the range, so no additional compressor is required to elevate above the system pressure required by the optional hydrogenation reactor 206. Preferred space velocities are from 0.5 to 5 hr ⁻¹ when operating with SPA catalyst, When operating with an ion exchange resin catalyst, it is 0.3 to 20 hr ⁻¹ , depending on the performance of the oligomerization reactor such as olefin component and type. Other catalysts are also applicable.

The oligomerization reactor product is discarded from the effluent line 220 of the oligomerization reactor 200. Some of the oligomerization reactor effluent may be recycled to the oligomerization reactor via recycle line 216 to control the calorific value. The second portion of the oligomerization reactor product passes through process line 222 to flash drum 226 where an unreacted vapor stream and an oligomerization product-rich liquid stream are fed. Unreacted steam stream exits flash drum 226 for further processing via steam line 228. A portion of the vapor stream in line 228 may be recycled to line oligomerization reactor 200 via line 230 after condensation and compression. The sufficiently oligomerized product stream in line 232 is removed from the bottom of the flash drum 226. A purge in line 234 to remove paraffin from the unreacted vapor stream in line 228 joins line 232 to feed line 236, which becomes line 162, 162 'or 172. do.

In yet another embodiment, the first and / or second conversion zone can be an aromatic alkylation reactor 300 as shown in FIG. 5. The aromatic alkylation reactor 300 may be in downstream communication with the bottom lines 144, 144 ″ of the LPG splitter column 140 of FIGS. 1 and 3. The same or separate aromatic alkylation reactor 300 is the bottom line 134, 134 ′ coming from the process fractionation column 130, 130 ′ and / or the overhead lines of the naphtha splitter column 150 of FIGS. 1 and 2. 154, 154 ') and downstream communication. In one embodiment, the bottom stream of diolefins or overhead lines 154, 154 ′ in lines 144, 144 ″ may be provided with an optional hydrogenation zone for selectively saturating the diolefins without they being fully saturated with paraffins. The optional hydrogenation catalyst in 306 is sent to line 302 for a first reaction. Suitable conditions for operating the selective hydrogenation process are described in FIG. 4. Hydrogen is passed from line 308 to reactor 306.

A stream comprising olefins and paraffins from the selective hydrogenation reactor 306 in line 31 is injected into the alkylation reactor 300. In one aspect, a dryer (not shown) in line 310 may be used to remove water that may affect the catalyst and to lower the concentration. Other boundary layers can also be considered to eliminate the toxicity of the catalyst. Although the alkyl conversion reaction takes place in the alkylation reactor 300, the alkylation reaction is very effective. The alkylation reactor is shown as an upstream reactor for the aromatic stream, but downstream reactors are also applicable. The stream in line 310 of olefins and paraffins enters each of several lines 312 into the pre-bed spaces prior to entering the catalyst beds 332, 334 and 335 into the alkylation reactor 300. Injection via 314 and 316. Catalyst layers 332, 334 and 336 contain alkylation catalysts for alkyl acid aromatics and olefins for preparing alkylbenzenes. The aromatic feed stream in line 340 is initially mixed with olefins and paraffins from line 316 in pre-bed space 326 and fed to alkylation reactor 300, which together enters catalyst bed 336. The aromatic feed stream in line 340 may be introduced in downstream communication with line 192 of FIGS. 1, 2 or 3, or preferably as part of an external stream derived from pyrolysis gasoline from a steam cracking unit after hydrotreating. . Other aromatic stream feedstocks may also be considered.

Effluent from catalyst bed 336 is mixed with fresh olefins and paraffins from line 314 in pre-bed space 324 and enters catalyst bed 334 together. Effluent from catalyst bed 334 is mixed with fresh olefins and paraffins from line 312 in pre-bed space 322 and enters catalyst bed 332 together. The process is repeated in number of layers of alkylation reactor 300. Although only three catalyst beds are shown in alkylation reactor 300, more or less layers and additional reactors are applicable. The alkylation effluent of the alkylation reactor 300 is conveyed to effluent line 342. Heat exchanger 344 may cool the exhaust in line 342 to an ideal temperature. Although not shown, the alkylation reactor effluent stream may be depressurized through the pressure regulating valve or at atmospheric pressure as it passes through the pump. Effluent line 342 carrying the alkylated product and unreacted paraffin may be line 162, 162 ′, 162 ″ or 172.

Benzene is the most important representative compound of alkylable aromatic compounds used as alkylation substrate in line 340. The aromatic feed stream may comprise 5 to 99.9 mole percent benzene. More generally the aromatic compound may be selected from the group consisting of benzene, naphthalene, anthracene, phenanthracene and substituted derivatives thereof. The most important class of substituents based on the aromatic nucleus of an alkylable aromatic compound are the mono- or poly-alkyl components containing 1 to 20 carbon atoms. Other important substituents are the hydroxyl component and the alkoxy component (the alkyl group contains 1 to 20 carbon atoms).

Various types of catalysts can be used in the alkylation reaction zone. Preferred catalysts for use in the present invention are zeolite catalysts. The catalyst of the present invention can typically be used in combination with a refractory inorganic oxide binder. Preferred binders are alumina or silica. Suitable zeolites include beta zeolites, ZSM-5, PSH-3, MCM-22, MCM-36, MCM-49, and MCM-56. Beta zeolites are disclosed in US Pat. No. 5,723,710. Preferred alkylation catalyst is UZM-8. FAU structures and catalysts applied are suitable. The zeolite may be present in an amount of at least 50% by weight of the catalyst, more preferably at least 60% by weight of the catalyst. However, when zeolites are provided on laminated spheres or reinforced surfaces, much lower zeolite concentrations are needed.

The specific conditions under which the alkylation reaction is carried out depend on the aromatic compounds and olefins used. Since the reaction is carried out at least in part in liquid phase conditions, the reaction pressure is adjusted to maintain at least some olefins in the liquid phase. Olefin feeds in the gas phase are also suitable. For heavy olefins the reaction can be carried out at autogenous pressure. The pressure can be adjusted over a wide range of 101 to 13172 kPa (gauge) (1 to 1900 psig). For practical reasons the pressure is usually in the range of 1379 to 6985 kPa (gauge) (200 to 1000 psig), but typically in the range of 2069 to 4137 kPa (gauge) (300 to 600 psig). Suitable temperature ranges for the olefins and alkylable aromatic compounds in the C ₄ -C ₇ range are from 60 ° C. to 400 ° C., and the most useful temperature ranges are from 90 ° C. to 250 ° C. Reactant is generally adequate mass flow of a liquid hourly space velocity on the yield (liquid hourly space velocity) 0.2 to 50 hr ^-1, especially from 0.5 to 10 hr ^- pass through the alkylation zone to ^one. The ratio of alkylable aromatic compound to olefin should be 1: 1 to 20: 1, with a ratio of 2.0 to 1.0 being preferred.

Without further elaboration, one skilled in the art believes that the present invention may be practiced from the foregoing description. Certain preferred embodiments of the above are to be considered merely illustrative and are not to be construed as limiting the description of the invention in any form.

In the above, unless stated otherwise, all temperatures are in degrees Celsius, and all parts and percentages are parts by weight.

From the above description, those skilled in the art can easily identify the essential characteristics of the present invention, and various changes and modifications can be made to suit various uses and conditions without departing from the spirit and scope of the present invention.

Claims (10)

C ₄ olefins and paraffins and C ₅ Passing C ₇ olefins and paraffins to the conversion zone to convert C ₄ olefins to higher molecular weight C ₄ derived compounds and C ₅ C ₅ olefins alkylated with aromatics to give C ₅ C ₇ olefins with higher molecular weight C ₅ Converting to a C ₇ derived compound;
Separating the C ₄ derived compound from C ₄ olefins and paraffins;
C ₅ C ₅ from C ₇ olefins and paraffins Separating the C ₇ derived compound; And
C ₄ derived compounds and C ₅ Feeding the C ₇ derived compound to the FCC reactor
Method for converting an olefin comprising a heavy compound. The method of claim 1,
The C ₄ olefins and paraffins and the C ₅ The C ₇ olefin and paraffin pass through the same conversion zone. The method of claim 1,
The C ₄ olefins and paraffins and the C ₅ The C ₇ olefins and paraffins are passed through different conversion zones. The method of claim 3,
Wherein the first conversion zone through which the C ₄ olefins and paraffin pass is an oligomerization zone. The method of claim 3,
Wherein said first conversion zone through which said C ₄ olefin and paraffin pass is an aromatic alkylation zone. C ₅ to the first transition zone C ₅ passing through a first stream of C ₇ olefins and paraffins; C ₇ olefins with higher molecular weight C ₅ Converting to a C ₇ derived compound;
A second conversion step of passing the second stream of C ₄ olefins and paraffins in the C ₄ olefin conversion zone with a larger molecular weight compounds derived from C ₄ and to separate the C ₄ compounds derived from C ₄ olefins and paraffins;
C ₅ C ₅ from C ₇ olefins and paraffins -Separating C ₇ derived compounds, C ₄ derived compounds and C ₅ Feeding the C ₇ derived compound to the FCC reactor
Method for converting an olefin comprising a heavy compound. The method according to claim 6,
C ₅ The first conversion zone through which the stream of C ₇ olefins and paraffins passes is selected from one of an aromatic alkylation zone and an oligomerization zone. A process fractionation column for separating an overhead stream comprising a C ₃ -rich overhead stream from a C ₅ -rich bottoms stream;
An aromatic alkylation reactor connected to the bottom line of the process fractionation column for alkylating aromatics and olefins in the C ₅ -rich bottoms stream;
A product column connected to said aromatic alkylation reactor for separating alkylaromatics from unreacted compounds from said C ₅ -rich bottoms stream; And
FCC reactor connected to the bottom line of the product column
A device for converting an olefin to a heavy compound, comprising: producing an FCC feed. 9. The method of claim 8,
And an LPG splitter column coupled to the overhead line of the process fractionation column to separate an LPG overhead stream comprising a C ₃ -rich overhead stream from a C ₄ -rich LPG bottoms stream. A process fractionation column for separating an overhead stream comprising a C ₃ -rich overhead stream from a C ₅ -rich bottoms stream;
A first switching section to switch to C _7-derived compound is associated with a bottom line of the process fractionation column C ₅ - - to C ₇ olefin is larger molecular weight C _5;
A second conversion zone connected with the overhead line of the process fractionation column to convert C ₄ olefins to C ₄ derived compounds having higher molecular weight;
A product splitter column connected to said first conversion zone and for separating a C ₅ -C ₇ derived compound from an unreacted compound; And
FCC reactor connected to the bottom line of the product splitter column
A device for converting an olefin to a heavy compound, comprising: producing an FCC feed.

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