CN116496814A - Method for producing light aromatic hydrocarbon by catalytic cracking - Google Patents
Method for producing light aromatic hydrocarbon by catalytic cracking Download PDFInfo
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- CN116496814A CN116496814A CN202210054106.4A CN202210054106A CN116496814A CN 116496814 A CN116496814 A CN 116496814A CN 202210054106 A CN202210054106 A CN 202210054106A CN 116496814 A CN116496814 A CN 116496814A
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- 238000004523 catalytic cracking Methods 0.000 title claims abstract description 173
- 150000004945 aromatic hydrocarbons Chemical class 0.000 title claims abstract description 84
- 238000004519 manufacturing process Methods 0.000 title abstract description 11
- 239000003921 oil Substances 0.000 claims abstract description 109
- 125000003118 aryl group Chemical group 0.000 claims abstract description 104
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 67
- 239000003054 catalyst Substances 0.000 claims abstract description 64
- 238000006243 chemical reaction Methods 0.000 claims abstract description 61
- 238000000605 extraction Methods 0.000 claims abstract description 37
- 238000000926 separation method Methods 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 28
- 239000010724 circulating oil Substances 0.000 claims abstract description 17
- 239000000295 fuel oil Substances 0.000 claims abstract description 16
- 230000009471 action Effects 0.000 claims abstract description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 57
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 51
- 239000007789 gas Substances 0.000 claims description 33
- 239000001257 hydrogen Substances 0.000 claims description 18
- 229910052739 hydrogen Inorganic materials 0.000 claims description 18
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 17
- 230000008569 process Effects 0.000 claims description 17
- 239000008096 xylene Substances 0.000 claims description 17
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 15
- 125000005575 polycyclic aromatic hydrocarbon group Chemical group 0.000 claims description 10
- 239000002904 solvent Substances 0.000 claims description 9
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims description 9
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 8
- 230000003197 catalytic effect Effects 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 4
- LCEDQNDDFOCWGG-UHFFFAOYSA-N morpholine-4-carbaldehyde Chemical compound O=CN1CCOCC1 LCEDQNDDFOCWGG-UHFFFAOYSA-N 0.000 claims description 4
- 238000005899 aromatization reaction Methods 0.000 claims description 2
- 239000003245 coal Substances 0.000 claims description 2
- 238000002407 reforming Methods 0.000 claims description 2
- 239000003079 shale oil Substances 0.000 claims description 2
- 238000004230 steam cracking Methods 0.000 claims description 2
- 239000000047 product Substances 0.000 description 45
- 239000000203 mixture Substances 0.000 description 22
- 239000002283 diesel fuel Substances 0.000 description 19
- 238000004821 distillation Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- -1 bicyclic aromatic hydrocarbons Chemical class 0.000 description 10
- 239000003502 gasoline Substances 0.000 description 7
- 229930195733 hydrocarbon Natural products 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000007795 chemical reaction product Substances 0.000 description 6
- 150000001924 cycloalkanes Chemical class 0.000 description 6
- 238000004817 gas chromatography Methods 0.000 description 6
- 150000002430 hydrocarbons Chemical class 0.000 description 6
- 239000000571 coke Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000004064 recycling Methods 0.000 description 5
- FYGHSUNMUKGBRK-UHFFFAOYSA-N 1,2,3-trimethylbenzene Chemical compound CC1=CC=CC(C)=C1C FYGHSUNMUKGBRK-UHFFFAOYSA-N 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 description 4
- 239000012263 liquid product Substances 0.000 description 4
- UOHMMEJUHBCKEE-UHFFFAOYSA-N prehnitene Chemical compound CC1=CC=C(C)C(C)=C1C UOHMMEJUHBCKEE-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000004587 chromatography analysis Methods 0.000 description 3
- 238000006482 condensation reaction Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 239000003546 flue gas Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002808 molecular sieve Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000012188 paraffin wax Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 3
- 238000006276 transfer reaction Methods 0.000 description 3
- YBYIRNPNPLQARY-UHFFFAOYSA-N 1H-indene Chemical compound C1=CC=C2CC=CC2=C1 YBYIRNPNPLQARY-UHFFFAOYSA-N 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical compound C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- YNPNZTXNASCQKK-UHFFFAOYSA-N phenanthrene Chemical compound C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000011959 amorphous silica alumina Substances 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 239000004305 biphenyl Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000004517 catalytic hydrocracking Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- RMBPEFMHABBEKP-UHFFFAOYSA-N fluorene Chemical compound C1=CC=C2C3=C[CH]C=CC3=CC2=C1 RMBPEFMHABBEKP-UHFFFAOYSA-N 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- NIHNNTQXNPWCJQ-UHFFFAOYSA-N o-biphenylenemethane Natural products C1=CC=C2CC3=CC=CC=C3C2=C1 NIHNNTQXNPWCJQ-UHFFFAOYSA-N 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 125000003367 polycyclic group Chemical group 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G69/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process
- C10G69/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process plural serial stages only
- C10G69/04—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process plural serial stages only including at least one step of catalytic cracking in the absence of hydrogen
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The application relates to a method for producing light aromatic hydrocarbon by catalytic cracking, which comprises the following steps: introducing raw oil into a hydrotreating unit, carrying out hydrogenation reaction under the action of a hydrogenation catalyst, introducing the obtained hydrogenation component into a catalytic cracking unit, and contacting and reacting with the catalytic cracking catalyst in a catalytic cracking reactor of the catalytic cracking unit; introducing the reaction oil gas generated by the catalytic cracking unit into a product separation unit for separation to respectively obtain cracked gas, light aromatic fraction, heavy aromatic fraction, circulating oil fraction and heavy oil fraction; introducing the heavy aromatic fraction into the catalytic cracking unit, and contacting and reacting with a catalytic cracking catalyst in the catalytic cracking reactor; and introducing the light aromatic fraction into an aromatic extraction unit for extraction to obtain C6-C8 light aromatic and raffinate oil respectively. The method of the invention converts C9+ arene rich in the heavy arene fraction into C6-C8 arene, thereby improving the yield of light arene.
Description
Technical Field
The invention relates to the field of petrochemical industry, in particular to a method for producing light aromatic hydrocarbon by catalytic cracking.
Background
In recent years, with the reduction of the demand of automotive diesel in China year by year, the reduction of the yield of the diesel and the reduction of the diesel-to-gasoline ratio are the problems which are urgently needed to be solved by refineries in the current and future time. The diesel oil related to the oil refinery mainly comprises straight-run diesel oil, catalytic cracking light cycle oil, coked diesel oil, thermal cracking diesel oil, hydrocracking diesel oil, aromatized diesel oil and the like, wherein the catalytic cracking light cycle oil is one of important products of a catalytic cracking device, and has the defects of high density, high aromatic hydrocarbon content, low cetane number and the like, so that the requirements of the diesel oil standard for vehicles are difficult to be met even through hydro-upgrading. Light aromatic hydrocarbons such as benzene, toluene and xylene are very important chemical raw materials, can be used for producing chemical products such as styrene, terephthalic acid (PTA), dimethyl terephthalate (DMT) and the like, and have the advantages of increasing the demand quantity year by year and broad market prospect. As the diesel oil contains a large amount of polycyclic aromatic hydrocarbons such as the bicyclic aromatic hydrocarbons, if the polycyclic aromatic hydrocarbons can be converted into light aromatic hydrocarbons through a reasonable processing process, the light cycle oil yield of a catalytic cracking device can be reduced, and high-value chemical raw materials can be produced.
US4585545 discloses a method for producing gasoline rich in aromatic hydrocarbons, which comprises the steps of hydrotreating a whole fraction of catalytically cracked light cycle oil, and then removing the obtained hydrogenated diesel oil for catalytic cracking to produce gasoline rich in monocyclic aromatic hydrocarbons.
CN110551526a discloses a method for processing catalytic cracking light cycle oil, which comprises the following steps: (1) Contacting the catalytic cracking light cycle oil with a hydrotreating catalyst and hydrotreating to obtain hydrogenated light cycle oil; (2) Sending the obtained hydrogenated light cycle oil and hydrogen-containing gas into a catalytic cracking reactor to contact with a catalytic cracking catalyst and perform catalytic cracking reaction to obtain a reaction product and a spent catalyst; (3) Feeding the obtained spent catalyst into a regenerator for regeneration, and feeding the obtained regenerated catalyst into a catalytic cracking reactor as the catalytic cracking catalyst; (4) And separating the obtained reaction product to obtain a dry gas product, a liquefied gas product, a gasoline product, a light cycle oil product and a heavy oil product. The processing method of the invention has the advantages of high yield of the aromatic hydrocarbon-rich gasoline, low coke generation and good raw material utilization rate.
CN103923698A discloses a catalytic conversion method for producing aromatic compounds, in the method, inferior heavy cycle oil and residual oil are subjected to hydrotreating reaction in the presence of hydrogen and hydrogenation catalyst, and reaction products are separated to obtain gas, naphtha, hydrogenated diesel oil and hydrogenated residual oil; the hydrogenated diesel oil enters a catalytic cracking device to carry out cracking reaction in the presence of a catalytic cracking catalyst, and the reaction products are separated to obtain dry gas, liquefied gas, catalytic gasoline rich in benzene, toluene and xylene, catalytic light diesel oil, distillate with the distillation range of 250-450 ℃ and slurry oil; wherein the distillate with the distillation range of 250-450 ℃ is sent to a residual oil hydrotreater for recycling. The method fully utilizes the residual oil hydrogenation condition to saturate the aromatic ring in the inferior heavy cycle oil to the greatest extent, thereby maximizing the production of benzene, toluene and xylene in the catalytic cracking of the hydrogenated diesel oil.
At present, the light cycle oil is subjected to catalytic cracking after being subjected to hydrotreatment, so that the double-ring aromatic hydrocarbon in the light cycle oil can be converted into light aromatic hydrocarbon, but the yield of the light aromatic hydrocarbon in the prior art is low as a whole.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a catalytic conversion method for producing light aromatic hydrocarbon by catalytic cracking, which returns heavy aromatic hydrocarbon fraction rich in C9+ aromatic hydrocarbon to a catalytic cracking reactor for secondary conversion, and returns circulating oil fraction to a hydrotreating unit for recycling, thereby improving the yield of light aromatic hydrocarbon such as benzene, toluene and xylene.
The application provides a method for producing light aromatic hydrocarbon by catalytic cracking, which comprises the following steps:
s1, introducing raw oil into a hydrotreating unit, carrying out hydrogenation reaction under the action of a hydrogenation catalyst, introducing the obtained hydrogenation component into a catalytic cracking unit, and contacting and reacting with the catalytic cracking catalyst in a catalytic cracking reactor of the catalytic cracking unit;
s2, introducing the reaction oil gas generated by the catalytic cracking unit into a product separation unit for separation to respectively obtain cracked gas, light aromatic fraction, heavy aromatic fraction, circulating oil fraction and heavy oil fraction;
s3, introducing the heavy aromatic fraction into the catalytic cracking unit, and enabling the heavy aromatic fraction to contact with a catalytic cracking catalyst in the catalytic cracking reactor and react;
s4, introducing the light aromatic fraction into an aromatic extraction unit for extraction to obtain C6-C8 light aromatic and raffinate oil respectively.
In one embodiment, the heavy aromatic fraction and the hydrogenation component are fed at different locations in the catalytic cracking reactor, with a heavy aromatic fraction feed inlet located below a hydrogenation component feed inlet.
In one embodiment, the height of the heavy aromatic fraction feed inlet from the bottom of the catalytic cracking reactor is 0 to 1/3, preferably 0 to 1/5, more preferably 0 to 1/10 of the total height of the catalytic cracking reactor; the height of the hydrogenation component feed inlet from the bottom of the catalytic cracking reactor is 1/3-2/3, preferably 1/3-1/2, more preferably 1/3-2/5 of the total height of the catalytic cracking reactor.
In one embodiment, the raffinate oil is also introduced to the catalytic cracking unit.
In one embodiment, the light aromatic fraction and the heavy aromatic fraction are cut at a point of 150 to 190 ℃, preferably 160 to 180 ℃; the cutting point of the heavy aromatic fraction and the circulating oil fraction is 200-270 ℃, preferably 230-260 ℃; the cutting point of the cycle oil fraction and the heavy oil fraction is 340 to 370 ℃, preferably 350 to 360 ℃.
In one embodiment, the content of C6-C8 aromatics in the light aromatic fraction is not less than 40 wt%, preferably not less than 50 wt%; the content of c9+ aromatic hydrocarbons in the heavy aromatic fraction is not less than 50 wt%, preferably not less than 70 wt%.
In one embodiment, the reaction temperature of the hydrotreating unit is 350-450 ℃, the hydrogen partial pressure is 5-15 MPa, and the volume space velocity is 2-15 h -1 Hydrogen oil volume ratio of 400-1600 Nm 3 /m 3 。
In one embodiment, the polycyclic aromatic hydrocarbon content of the hydrogenation component is no greater than 25 wt%, preferably no greater than 15 wt%.
In one embodiment, the reaction temperature of the catalytic cracking reactor is 500-700 ℃, preferably 550-650 ℃, the mass ratio of the catalyst to the oil is 1-60, preferably 4-20, the oil-gas residence time is 0.2-10 s, preferably 0.5-7 s, and the reaction pressure (gauge pressure) is 0-0.2 MPa, preferably 0-0.15 MPa.
In one embodiment, the aromatic hydrocarbon extraction unit has a top temperature of 80 to 100 ℃, preferably 85 to 95 ℃, a bottom temperature of 170 to 190 ℃, preferably 175 to 185 ℃, and a pressure (gauge pressure) of 0.2 to 0.6MPa, preferably 0.4 to 0.55MPa.
In one embodiment, the extraction solvent used in the aromatic hydrocarbon extraction unit is one or more of sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, and formylmorpholine.
In one embodiment, the aromatic hydrocarbon extraction unit produces a C6 to C8 light aromatic hydrocarbon having a sum of benzene, toluene and xylene content of not less than 95 wt%, preferably not less than 98 wt%.
In one embodiment, the cycle oil fraction is also introduced into the hydroprocessing unit for hydrogenation; and/or the number of the groups of groups,
and introducing heavy aromatic hydrocarbon fractions generated by other devices into the catalytic cracking reactor for reaction, wherein the other devices comprise one or more of a steam cracking device, a catalytic cracking device, a hydrogenation device, a reforming device and an aromatization device.
In one embodiment, the raw oil is one or more of straight-run diesel oil, catalytic cracking light cycle oil, coker diesel oil, thermal cracking diesel oil, aromatizer diesel oil, direct coal liquefaction diesel oil and shale oil diesel oil.
Firstly, raw oil, particularly catalytic cracking light cycle oil rich in polycyclic aromatic hydrocarbon, is subjected to hydrotreatment, is converted into hydrogenation components rich in monocyclic aromatic hydrocarbon, and then is subjected to contact reaction with a catalytic cracking catalyst to be converted into light aromatic hydrocarbon such as benzene, toluene and xylene; the heavy aromatic fraction rich in C9+ aromatic hydrocarbon in the catalytic cracking reaction product is returned to the catalytic cracking reactor for continuous reaction, and is fed at the lower part of the hydrogenation component, so that on one hand, the C9+ aromatic hydrocarbon can be converted into light aromatic hydrocarbon such as benzene, toluene and xylene, and on the other hand, the activity of the catalyst can be reduced, the hydrogenation component can inhibit hydrogen transfer and condensation reaction when contacting with the catalyst, and the yield of the light aromatic hydrocarbon is improved; in addition, the circulating oil fraction rich in polycyclic aromatic hydrocarbon in the catalytic cracking product is returned to the hydrotreating unit for recycling, so that the utilization rate of the raw materials is further improved.
Drawings
FIG. 1 shows a schematic flow diagram of one embodiment of the present invention.
Detailed Description
The present application is further described in detail below by way of the accompanying drawings and examples. The features and advantages of the present application will become more apparent from the description.
The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
In addition, the technical features described below in the different embodiments of the present application may be combined with each other as long as they do not collide with each other.
The method provided by the present invention will be further described with reference to fig. 1, it being understood that the embodiments described herein are for purposes of illustration and explanation only, and are not intended to limit the present invention.
In the present invention, any matters or matters not mentioned are directly applicable to those known in the art without modification except for those explicitly stated. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or ideas thus formed are all considered as part of the original disclosure or original description of the present invention, and should not be considered as new matters not disclosed or contemplated herein unless such combination would obviously be unreasonable to one skilled in the art.
All of the features disclosed in this invention may be combined in any combination which is understood to be disclosed or described in this invention unless the combination is obviously unreasonable by those skilled in the art. The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The application provides a method for producing light aromatic hydrocarbon by catalytic cracking, which comprises the following steps:
s1, introducing raw oil into a hydrotreating unit, carrying out hydrogenation reaction under the action of a hydrogenation catalyst, introducing the obtained hydrogenation component into a catalytic cracking unit, and contacting and reacting with the catalytic cracking catalyst in a catalytic cracking reactor of the catalytic cracking unit;
s2, introducing the reaction oil gas generated by the catalytic cracking unit into a product separation unit for separation to respectively obtain cracked gas, light aromatic fraction, heavy aromatic fraction, circulating oil fraction and heavy oil fraction;
s3, introducing the heavy aromatic fraction into the catalytic cracking unit, and enabling the heavy aromatic fraction to contact with a catalytic cracking catalyst in the catalytic cracking reactor and react;
s4, introducing the light aromatic fraction into an aromatic extraction unit for extraction to obtain C6-C8 light aromatic and raffinate oil respectively.
The method of the present application is further described below in conjunction with fig. 1.
In this application, light aromatic hydrocarbon refers to C6-C8 aromatic hydrocarbon including benzene, toluene, xylene, etc. "polycyclic aromatic hydrocarbon" refers to aromatic hydrocarbons containing two or more benzene rings, and includes non-condensed ring type aromatic hydrocarbons such as biphenyl, and polycyclic substituted aliphatic hydrocarbons, and condensed ring type aromatic hydrocarbons such as naphthalene, anthracene, phenanthrene, indene, fluorene, acenaphthene, hydrocarbon derivatives thereof, and the like. "monocyclic aromatic hydrocarbon" means an aromatic hydrocarbon containing one benzene ring, such as benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, and the like. "C9+ aromatic hydrocarbon" means an aromatic hydrocarbon having 9 or more carbon atoms, such as trimethylbenzene, tetramethylbenzene, etc.
The process provided by the present invention can be carried out by a production apparatus as described in fig. 1, which comprises at least a hydrotreating unit 2, a catalytic cracking unit 3, a product separation unit 4 and an aromatic hydrocarbon extraction unit 5.
In the present invention, the hydrotreating unit 2 is used to hydrotreat the material in the hydrotreating unit 2 to convert the material into a hydrogenation component 204 rich in monocyclic aromatic hydrocarbon. As shown in fig. 1, the material in the hydroprocessing unit 2 may include a feedstock 101 and a cycle oil fraction 409 from the product separation unit 4, and the cycle oil fraction 409 from the product separation unit 4 may be recycled back to the hydroprocessing unit 2, improving the yield of product light aromatics. The hydrogenation reactor of the hydrotreating unit 2 may be a fixed bed reactor, and a plurality of hydrogenation reactors may be arranged in series or in parallel in order to increase the throughput of the hydrotreating unit.
In one embodiment, the reaction temperature of the hydrotreating unit 2 is 350-450 ℃, the hydrogen partial pressure is 5-15 MPa, and the volume space velocity is 2-15 h -1 Hydrogen oil volume ratio of 400-1600 Nm 3 /m 3 . The hydrogenation catalyst comprises an active component and a carrier, wherein the active component is selected from a group VIB metal, a group VIII non-noble metal or a mixture of two metals, and the carrier is selected from one or a mixture of more of alumina, silica and amorphous silica-alumina. The content of polycyclic aromatic hydrocarbon in the hydrotreated component 204 is not more than 25 wt%, preferably not more than 15 wt%.
In the present invention, the catalytic cracking unit 3 includes a catalytic cracking reactor and a regenerator (not shown), the hydrogenation component 204 and the catalytic cracking catalyst react in contact in the catalytic cracking reactor, the generated oil mixture is separated by a separating device, the generated reaction oil gas 305 is introduced into the product separating unit 4, the spent catalyst is introduced into the regenerator for regeneration after being stripped, and the regenerated catalytic cracking catalyst is returned to the reactor for recycling.
The catalytic cracking reactor of the catalytic cracking unit 3 may use various reactors commonly used in the art, and may be selected from, for example, one or more types of combination of fixed bed reactors, moving bed reactors, fluidized bed reactors, riser reactors, preferably riser reactors selected from one of equal-diameter riser reactors and variable-diameter riser reactors.
In this application, the heavy aromatic fraction 408 from the product separation unit 4 is also introduced into the catalytic cracking unit 3 where it contacts and reacts with the catalytic cracking catalyst. The heavy aromatics fraction 408 contains c9+ aromatics, which are recycled directly back to the catalytic cracking reactor of catalytic cracking unit 3 for catalytic cracking reactions. The present application specifically distinguishes the products separated by the product separation unit 4, and respectively obtains a light aromatic fraction 407, a heavy aromatic fraction 408 and a circulating oil fraction 409, and adopts different treatment modes for the three different fractions: the light aromatic fraction 407 is directly subjected to extraction treatment to obtain a target product C6-C8 light aromatic; the heavy aromatic fraction 408 is directly recycled to the catalytic cracking unit 3 for catalytic cracking reaction; while the cycle oil fraction 409 is recycled back to the hydroprocessing unit 2 for hydroprocessing. The treatment mode can not only improve the yield of target products C6-C8 light aromatic hydrocarbon, but also reduce the load of a hydrotreating unit, reduce the hydrogen consumption and the like.
As shown in fig. 1, in one embodiment, the catalytic cracking reactor may be provided with a heavy aromatic fraction feed inlet 301 and a hydrogenation component feed inlet 303, which are provided at different positions of the catalytic cracking reactor, and the heavy aromatic fraction feed inlet 301 and the hydrogenation component feed inlet 303 are sequentially provided from bottom to top. As shown in fig. 1, heavy aromatic fraction feed port 301 is used to feed heavy aromatic fraction 408 and hydrogenation component feed port 303 is used to feed hydrogenation component 204 from hydrotreating unit 2. In one embodiment, the height of the heavy aromatic fraction feed inlet 301 from the bottom of the catalytic cracking reactor is 0 to 1/3, preferably 0 to 1/5, more preferably 0 to 1/10 of the total height of the catalytic cracking reactor; the height of the hydrogenation component feed inlet 303 from the bottom of the catalytic cracking reactor is 1/3 to 2/3, preferably 1/3 to 1/2, more preferably 1/3 to 2/5 of the total height of the catalytic cracking reactor. By adopting the feeding mode, the heavy aromatic fraction 408 can be contacted with the high-temperature regenerated catalyst, so that a small amount of carbon deposit is generated on the regenerated catalyst, and the activity of the regenerated catalyst is reduced, thereby inhibiting the occurrence of hydrogen transfer and condensation reaction when the hydrogenation component is contacted with the catalyst, facilitating the hydrogenation component to be converted into C6-C8 light aromatic hydrocarbons more, and improving the yield of the C6-C8 light aromatic hydrocarbons.
In one embodiment, the raffinate 512 may also be introduced into the catalytic cracking unit 3 for catalytic cracking reactions. In one embodiment, the raffinate oil 512 and the heavy aromatic fraction 408 may be introduced together into the catalytic cracking unit 3 after being mixed for catalytic cracking reaction. The feed position of the mixed fraction may be the above heavy aromatic fraction feed port 301, which is also located below the hydrogenation component feed port 303 in the catalytic cracking reactor, and the height from the bottom of the catalytic cracking reactor is 0 to 1/3, preferably 0 to 1/5, more preferably 0 to 1/10 of the total height of the catalytic cracking reactor.
In addition, in one embodiment, the heavy aromatic fraction produced by other devices including one or more of a steam cracker, a catalytic cracker, a hydrotreater, a reformer, and an aromatizer may be introduced into the catalytic cracking reactor of the catalytic cracking unit 3 for reaction.
The reaction temperature of the catalytic cracking reactor in the catalytic cracking unit 3 is 500-700 ℃, preferably 550-650 ℃, the mass ratio of catalyst to oil is 1-60, preferably 4-20, the residence time of oil gas is 0.2-10 s, preferably 0.5-7 s, and the reaction pressure (gauge pressure) is 0-0.2 MPa, preferably 0-0.15 MPa. The catalytic cracking catalyst comprises 15-60 wt% of cracking active components, 15-90 wt% of matrix and 0-20 wt% of binder, wherein the cracking active components are selected from one or a mixture of a plurality of unmodified, phosphorus-modified, rare earth-modified or phosphorus-and-rare earth-modified Y molecular sieves, beta molecular sieves and ZSM-5 molecular sieves. The catalytic cracking catalyst has an activity of not less than 65, preferably not less than 68.
In the present invention, the product separation unit 4 is used to separate the reaction oil gas 305 from the catalytic cracking unit 3 into various products. The product separation unit 4 generally adopts rectification separation, and can be in the forms of a plate tower, a floating valve tower, a packing tower and the like, and the separation requirement is met by setting reasonable theoretical plate numbers and tower diameters. The reaction oil gas 305 generated by the catalytic cracking unit 3 can be separated into a cracked gas 406, a light aromatic fraction 407, a heavy aromatic fraction 408, a cycle oil fraction 409, and a heavy oil fraction 410 by the product separation unit 4. The light aromatic fraction 407 and the heavy aromatic fraction 408 have a cut point of 150 to 190 ℃, preferably 160 to 180 ℃. The cutting point of the heavy aromatic fraction 408 and the cycle oil fraction 409 is 200 to 270 ℃, preferably 230 to 260 ℃. The cutting point of the cycle oil fraction 409 and the heavy oil fraction 410 is 340 to 370 ℃, preferably 350 to 360 ℃.
In one embodiment, the content of C6-C8 aromatics in the light aromatic fraction 407 is not less than 40 wt%, preferably not less than 50 wt%. The content of c9+ aromatics in the heavy aromatics fraction 408 is not less than 50 wt%, preferably not less than 70 wt%. As described above, the heavy aromatic fraction 408 is introduced into the catalytic cracking unit 3 to continue the reaction, and the cycle oil fraction 409 is introduced into the hydrotreating unit 2 to perform the hydrogenation reaction.
In the present invention, the aromatic hydrocarbon extraction unit 5 is used for C6 to C8 aromatic hydrocarbons in the light aromatic hydrocarbon fraction 407. The aromatic hydrocarbon extraction unit 5 may employ an extraction column having a column top temperature of 80 to 100 ℃, preferably 85 to 95 ℃, a column bottom temperature of 170 to 190 ℃, preferably 175 to 185 ℃, and a pressure (gauge pressure) of 0.2 to 0.6MPa, preferably 0.4 to 0.55MPa. The extraction solvent used in the aromatic hydrocarbon extraction unit 5 may be one or more of sulfolane, N-methylpyrrolidone, dimethyl sulfoxide and formyl morpholine. The sum of benzene, toluene and xylene content in the C6-C8 aromatic 511 obtained by the aromatic extraction unit 5 is not less than 95% by weight, preferably not less than 98% by weight. As previously described, the resulting raffinate 512 may be introduced into the catalytic cracking unit 3 to continue the catalytic cracking reaction. The raffinate oil 512 may also be used as a gasoline blending component.
In the present invention, the catalytic cracking light cycleAfter the oil 101 is preheated to 150-250 ℃, the oil is sprayed into a hydrogenation reactor of a hydrogenation treatment unit 2 through a nozzle, and the oil and a hydrogenation catalyst react at the temperature of 350-450 ℃, the hydrogen partial pressure of 5-15 MPa and the volume space velocity of 2-15 h -1 Hydrogen oil volume ratio of 400-1600 Nm 3 /m 3 The obtained hydrogenation component 204 is introduced into a hydrogenation component feed inlet 303 of a catalytic cracking reactor in a catalytic cracking unit 3, sprayed into the catalytic cracking reactor through a nozzle, and is contacted and reacted with a catalytic cracking catalyst from the bottom of the catalytic cracking reactor at a reaction temperature of 500-700 ℃, preferably 550-650 ℃, a catalyst-to-oil mass ratio of 1-60, preferably 4-20, an oil-gas residence time of 0.2-10 s, preferably 0.5-7 s, and a reaction pressure (gauge pressure) of 0-0.2 MPa, preferably 0-0.15 MPa, and the generated reaction oil gas 305 is introduced into a product separation unit 4 for separation to obtain a cracked gas 406, a light aromatic fraction 407, a heavy aromatic fraction 408, a circulating oil fraction 409 and a heavy oil fraction 410, respectively. Wherein, the light aromatic fraction 407 is introduced into an aromatic extraction unit 5, and is extracted in an extraction tower under the conditions that the tower top temperature is 80-100 ℃, preferably 85-95 ℃, the tower bottom temperature is 170-190 ℃, preferably 175-185 ℃, the pressure is 0.2-0.6 MPa, preferably 0.4-0.55 MPa, and the extraction solvent is one or more of sulfolane, N-methylpyrrolidone, dimethyl sulfoxide and formylmorpholine, and the sum of the contents of benzene, toluene and xylene is not less than 95 wt%, preferably not less than 98 wt% of C6-C8 aromatic 511 and raffinate 512 are obtained by extraction; the heavy aromatic fraction 408 is returned to the heavy aromatic fraction feed inlet 301 on the catalytic cracking reactor, is sprayed into the catalytic cracking reactor through a nozzle, and is contacted and reacted with the catalytic cracking catalyst from the bottom of the catalytic cracking reactor. The heavy aromatic fraction 408 is introduced into the catalytic cracking reactor at a different location than the hydrogenation component 204, wherein the heavy aromatic fraction feed inlet 301 is located below the hydrogenation component feed inlet 301; the cycle oil fraction 409 is introduced into the hydrotreating unit 2 for hydrogenation.
The advantages of the invention include: firstly, raw oil, particularly catalytic cracking light cycle oil rich in polycyclic aromatic hydrocarbon, is subjected to hydrotreatment, is converted into hydrogenation components rich in monocyclic aromatic hydrocarbon, and then is subjected to contact reaction with a catalytic cracking catalyst to be converted into light aromatic hydrocarbon such as benzene, toluene and xylene; the heavy aromatic fraction rich in C9+ aromatic hydrocarbon in the catalytic cracking reaction product is returned to the catalytic cracking reactor for continuous reaction, and is fed at the lower part of the hydrogenation component, so that on one hand, the C9+ aromatic hydrocarbon can be converted into light aromatic hydrocarbon such as benzene, toluene and xylene, and on the other hand, the activity of the catalyst can be reduced, the hydrogenation component can inhibit hydrogen transfer and condensation reaction when contacting with the catalyst, and the yield of the light aromatic hydrocarbon is improved; in addition, the circulating oil fraction rich in polycyclic aromatic hydrocarbon in the catalytic cracking product is returned to the hydrotreating unit for recycling, so that the utilization rate of the raw oil is further improved.
The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.
Reagents, instruments and tests
In the examples and comparative examples of the present invention, the gas product was tested by the petrochemical analysis method RIPP 77-90, the coke content was measured by the petrochemical analysis method RIPP 107-90, and the composition of the organic liquid product was measured by the SH/T0558-1993 method.
In the examples below, the yield of the product was calculated according to the following formula:
the RIPP petrochemical analysis method used in the present invention is selected from the group consisting of "petrochemical analysis method (RIPP test method)", code Yang Cuiding, scientific Press, 1990.
The hydrogenation catalyst used in the hydrogenation unit comprises a hydrogenation catalyst RN-32V and a hydrogenation protection catalyst RG-1, wherein both catalysts are commercial catalysts and are produced by Qilu division of China petrochemical catalyst company. The catalytic cracking catalyst used in the catalytic cracking unit was produced by ziluta corporation, a petrochemical catalyst company, with a trade designation SLA-1, and its composition and properties are shown in table 1. The extraction solvent used in the aromatic hydrocarbon extraction unit is sulfolane.
TABLE 1 composition and Properties of SLA-1 catalyst
| Catalyst | SLA-1 |
| Chemical composition,% (w) | |
| Al 2 O 3 | 51.50 |
| Na 2 O | 0.15 |
| Specific surface area/(m) 2 ·g -1 ) | 125.0 |
| Pore volume/(cm) 3 ·g -1 ) | 0.3 |
| Particle size distribution,% (w) | |
| 0-20μm | 2.6 |
| 0-40μm | 21.7 |
| 0-80μm | 67.2 |
| 0-105μm | 84.1 |
| ＞105μm | 15.9 |
| Micro-inverse Activity,% (w) | 76 |
TABLE 2 Properties of catalytically cracked light cycle oil
| Project | Catalytic cracking light cycle oil |
| Density (20 ℃ C.)/(kg/m) 3 ) | 996.9 |
| Mass group composition/% | |
| Paraffin hydrocarbons | 1.2 |
| Cycloalkane (CNS) | 0.3 |
| Aromatic hydrocarbons | 98.5 |
| Monocyclic aromatic hydrocarbon | 14.4 |
| Distillation range/. Degree.C | |
| Initial point of distillation | 200 |
| 10％ | 233 |
| 30％ | 246 |
| 50％ | 255 |
| 70％ | 266 |
| 90％ | 299 |
| End point of distillation | 343 |
TABLE 3 composition and Properties of hydrogenated light cycle oil
| Project | Hydrogenated light cycle oil |
| Density (20 ℃ C.)/(kg/m) 3 ) | 910.4 |
| Mass group composition/% | |
| Paraffin hydrocarbons | 12.5 |
| Cycloalkane (CNS) | 19.6 |
| Aromatic hydrocarbons | 67.9 |
| Monocyclic aromatic hydrocarbon | 56.4 |
| Distillation range/. Degree.C | |
| Initial point of distillation | 155 |
| 10％ | 202 |
| 30％ | 226 |
| 50％ | 242 |
| 70％ | 261 |
| 90％ | 300 |
| End point of distillation | 336 |
TABLE 4 composition and Properties of heavy aromatic fractions
| Project | Heavy aromatic fraction |
| Density (20 ℃ C.)/(kg/m) 3 ) | 868.4 |
| Mass group composition/% | |
| Paraffin hydrocarbons | 14.60 |
| Cycloalkane (CNS) | 0.04 |
| Olefins | 0.59 |
| Aromatic hydrocarbons | 84.77 |
| Totals to | 100 |
| Distillation range/. Degree.C | |
| Initial point of distillation | 161 |
| 10％ | 165 |
| 30％ | 167 |
| 50％ | 172 |
| 70％ | 173 |
| 90％ | 179 |
| End point of distillation | 185 |
Example 1
Introducing preheated catalytic cracking light cycle oil into a hydrogenation unit for hydrotreating, introducing the obtained hydrogenated light cycle oil and heavy aromatic fraction into a small fixed fluidized bed reactor, sequentially introducing the heavy aromatic fraction and the hydrogenated light cycle oil from bottom to top into the feed inlets of the two raw materials, wherein the height of the feed inlets of the heavy aromatic fraction from the bottom of the catalytic cracking reactor is 1/10 of the total height of the catalytic cracking reactor, the height of the feed inlets of the hydrogenated light cycle oil from the bottom of the catalytic cracking reactor is 1/3 of the total height of the catalytic cracking reactor, contacting with SLA-1 catalyst therein for reaction, separating the produced oil mixture by a filter, introducing the separated oil gas into a product separation unit, and introducing the obtained cracked gas into a reactorThe composition is analyzed by gas chromatography, and liquid products (light aromatic hydrocarbon fraction, heavy aromatic hydrocarbon fraction, circulating oil fraction and heavy oil fraction) are collected and analyzed by gas chromatography for distillation range and hydrocarbon composition, wherein the heavy aromatic hydrocarbon fraction is circulated back to the fluidized bed reactor, and the light aromatic hydrocarbon fraction is extracted by taking sulfolane as an extraction solvent to obtain a light aromatic hydrocarbon component. The catalyst after the reaction is regenerated by oxygen, and CO in the regenerated flue gas is analyzed by chromatography 2 To calculate the yield of coke. The yields of the respective products were obtained by calculation. The properties of the light cycle oil obtained by the hydrotreatment unit and the heavy aromatic fraction obtained by the product separation unit are shown in tables 2, 3 and 4, respectively. The reaction conditions and results are shown in Table 5.
Example 2
The procedure of example 1 was followed, except that the reaction temperature of catalytic cracking was 590 ℃. The reaction conditions and results are shown in Table 5.
Comparative example 1
Introducing preheated catalytic cracking light cycle oil into a hydrogenation unit for hydrotreating, introducing the obtained hydrogenated light cycle oil into a small fixed fluidized bed reactor, wherein the height of a feed inlet of the hydrogenated light cycle oil from the bottom of the catalytic cracking reactor is 1/3 of the total height of the catalytic cracking reactor, contacting with an SLA-1 catalyst in the catalytic cracking reactor for reaction, separating the produced oil-gas mixture through a filter, introducing the separated oil gas into a product separation unit, analyzing the composition of the obtained cracked gas through gas chromatography, collecting liquid products (light aromatic hydrocarbon fraction, heavy aromatic hydrocarbon fraction, circulating oil fraction and heavy oil fraction), analyzing the distillation range and hydrocarbon composition through gas chromatography, and extracting the obtained light aromatic hydrocarbon fraction by using sulfolane as an extraction solvent to obtain light aromatic components. The catalyst after the reaction is regenerated by oxygen, and CO in the regenerated flue gas is analyzed by chromatography 2 To calculate the yield of coke. The yields of the respective products were obtained by calculation. The reaction conditions and results are shown in Table 5.
Comparative example 2
Introducing preheated catalytic cracking light cycle oilIn the small fixed fluidized bed reactor, in addition, heavy aromatic hydrocarbon fraction obtained by separation is introduced into the small fixed fluidized bed reactor, the heavy aromatic hydrocarbon fraction and the catalytic cracking light cycle oil are respectively fed into the feed inlets of the two raw materials from bottom to top in sequence, the height of the feed inlet of the heavy aromatic hydrocarbon fraction from the bottom of the catalytic cracking reactor is 1/10 of the total height of the catalytic cracking reactor, and the height of the feed inlet of the catalytic cracking light cycle oil from the bottom of the catalytic cracking reactor is 1/3 of the total height of the catalytic cracking reactor. All raw materials are contacted with SLA-1 catalyst in a reactor and react, the generated oil solution mixture is separated by a filter, the separated oil gas is introduced into a product separation unit, the obtained cracked gas is analyzed for composition by gas chromatography, liquid products (light aromatic hydrocarbon fraction, heavy aromatic hydrocarbon fraction, circulating oil fraction and heavy oil fraction) are collected and analyzed for distillation range and hydrocarbon composition by gas chromatography, wherein the heavy aromatic hydrocarbon fraction is circulated back to the fluidized bed reactor, and the light aromatic hydrocarbon fraction is extracted by using sulfolane as an extraction solvent to obtain light aromatic hydrocarbon components. The catalyst after the reaction is regenerated by oxygen, and CO in the regenerated flue gas is analyzed by chromatography 2 To calculate the yield of coke. The yields of the respective products were obtained by calculation. The reaction conditions and results are shown in Table 5.
TABLE 5 reaction conditions and results for examples 1-2 and comparative examples 1-2
| Project | Example 1 | Example 2 | Comparative example 1 | Comparative example 2 |
| Hydrotreatment unit | ||||
| Reaction temperature/. Degree.C | 420 | 420 | 420 | |
| Hydrogen partial pressure/MPa | 10 | 10 | 10 | |
| Volume space velocity/h -1 | 10 | 10 | 10 | |
| Hydrogen oil volume ratio/(Nm) 3 /m 3 ) | 1000 | 1000 | 1000 | |
| Catalytic cracking unit | ||||
| Reaction temperature/. Degree.C | 580 | 590 | 580 | 590 |
| Ratio of agent to oil | 8 | 8 | 8 | 8 |
| Airspeed/h -1 | 10 | 10 | 10 | 10 |
| Water-to-oil ratio | 10 | 10 | 10 | 10 |
| Product separation unit | ||||
| Cutting point/. Degree.C | ||||
| Light aromatic fraction and heavy aromatic fraction | 170 | 170 | 170 | 170 |
| Heavy aromatic fraction and cycle oil fraction | 255 | 255 | 255 | 255 |
| Cycle oil fraction and heavy oil fraction | 355 | 355 | 355 | 355 |
| Light aromatic yield/wt% | ||||
| Benzene | 3.24 | 3.35 | 1.85 | 1.81 |
| Toluene (toluene) | 12.51 | 13.11 | 7.59 | 7.91 |
| Xylene (P) | 12.41 | 12.85 | 7.41 | 9.11 |
| Sum of light aromatic hydrocarbons | 28.16 | 29.31 | 16.85 | 18.84 |
Example 3
Introducing preheated catalytic cracking light cycle oil into a fixed bed hydrogenation reactor, contacting with a mixed catalyst of a hydrotreating catalyst RN-32V and a hydrogenation protecting catalyst RG-1, performing hydrogenation reaction, introducing the obtained hydrogenated light cycle oil into a hydrogenation light cycle oil feed port of the catalytic cracking reactor, performing contact reaction with an SLA-1 catalyst from the bottom of the catalytic cracking reactor, introducing the produced reaction oil gas into a separation device for separation to respectively obtain cracked gas, a light aromatic fraction, a heavy aromatic fraction, a circulating oil fraction and a heavy oil fraction, wherein the light aromatic fraction is introduced into an aromatic extraction tower, sulfolane is used as an extraction solvent for extraction, obtaining C6-C8 aromatic hydrocarbons rich in benzene, toluene and xylene and raffinate oil, the heavy aromatic fraction is returned to a heavy aromatic fraction feed port of the catalytic cracking reactor, performing contact reaction with the catalytic cracking catalyst from the bottom of the catalytic cracking reactor, and introducing the circulating oil fraction into the hydrogenation reactor for hydrogenation reaction. Wherein, the height of the heavy aromatic fraction feed inlet from the bottom of the catalytic cracking reactor is 1/5 of the total height of the catalytic cracking reactor, and the height of the light hydrogenated circulating oil feed inlet from the bottom of the catalytic cracking reactor is 1/3 of the total height of the catalytic cracking reactor. The conditions and product yields for each treatment unit are shown in table 6.
Example 4
The process of example 3 was followed except that the heavy aromatic fraction feed inlet was 1/10 of the total catalytic cracking reactor height from the bottom of the catalytic cracking reactor and the hydrogenated light cycle oil feed inlet was 2/5 of the total catalytic cracking reactor height. The conditions and product yields for each treatment unit are shown in table 6.
Comparative example 3
The procedure of example 3 was followed, except that the heavy aromatic fraction obtained in the product separation unit was not returned to the catalytic cracking reactor for further reaction. The conditions and product yields for each treatment unit are shown in table 6.
Comparative example 4
The procedure of example 3 was followed, except that the heavy aromatic fraction obtained in the product separation unit was not returned to the catalytic cracking reactor to continue the reaction, and the cycle oil fraction obtained in the product separation unit was not introduced into the hydrotreating reactor to carry out the hydrogenation reaction. The conditions and product yields for each treatment unit are shown in table 6.
As can be seen from tables 5 and 6, the method and apparatus of the present invention can improve the yield of light aromatic hydrocarbon as compared with the comparative examples.
The present application has been described in connection with the preferred embodiments, but these embodiments are merely exemplary and serve only as illustrations. On the basis of this, many alternatives and improvements can be made to the present application, which fall within the scope of protection of the present application.
TABLE 6 reaction conditions and results for examples 3-4 and comparative examples 3-4
| Project | Example 3 | Example 4 | Comparative example 3 | Comparative example 4 |
| Hydrotreatment unit | ||||
| Reaction temperature/. Degree.C | 380 | 420 | 380 | 420 |
| Hydrogen partial pressure/MPa | 10 | 12 | 10 | 12 |
| Volume space velocity/h -1 | 8 | 12 | 8 | 12 |
| Hydrogen oil volume ratio/(Nm) 3 /m 3 ) | 600 | 1300 | 600 | 1300 |
| Catalytic cracking unit | ||||
| Reaction temperature/. Degree.C | 580 | 620 | 580 | 620 |
| Mass ratio of agent to oil | 6 | 12 | 10 | 12 |
| Residence time/s | 4 | 6 | 4 | 6 |
| Reaction pressure/MPa | 0.08 | 0.1 | 0.1 | 0.1 |
| Product separation unit | ||||
| Cutting point/. Degree.C | ||||
| Light aromatic fraction and heavy aromatic fraction | 170 | 180 | 170 | 180 |
| Heavy aromatic fraction and cycle oil fraction | 250 | 260 | 250 | 260 |
| Cycle oil fraction and heavy oil fraction | 350 | 360 | 350 | 360 |
| Aromatic hydrocarbon extraction unit | ||||
| Temperature at the top of the column/. Degree.C | 85 | 90 | 85 | 90 |
| Bottom temperature/°c | 175 | 180 | 175 | 180 |
| pressure/MPa | 0.42 | 0.52 | 0.42 | 0.52 |
| Product distribution/% | ||||
| Cracked gas | 18.31 | 19.78 | 17.16 | 18.15 |
| Benzene | 5.33 | 5.42 | 2.01 | 1.69 |
| Toluene (toluene) | 19.42 | 20.33 | 10.85 | 8.78 |
| Xylene (P) | 28.01 | 30.86 | 16.77 | 14.12 |
| Sum of light aromatic hydrocarbons | 52.76 | 56.61 | 29.63 | 24.59 |
Claims (14)
1. A process for producing light aromatic hydrocarbons by catalytic cracking comprising:
s1, introducing raw oil into a hydrotreating unit, carrying out hydrogenation reaction under the action of a hydrogenation catalyst, introducing the obtained hydrogenation component into a catalytic cracking unit, and contacting and reacting with the catalytic cracking catalyst in a catalytic cracking reactor of the catalytic cracking unit;
s2, introducing the reaction oil gas generated by the catalytic cracking unit into a product separation unit for separation to respectively obtain cracked gas, light aromatic fraction, heavy aromatic fraction, circulating oil fraction and heavy oil fraction;
s3, introducing the heavy aromatic fraction into the catalytic cracking unit, and enabling the heavy aromatic fraction to contact with a catalytic cracking catalyst in the catalytic cracking reactor and react;
s4, introducing the light aromatic fraction into an aromatic extraction unit for extraction to obtain C6-C8 light aromatic and raffinate oil respectively.
2. The process of claim 1 wherein the heavy aromatic fraction and the hydrogenation component are fed at different locations in the catalytic cracking reactor with a heavy aromatic fraction feed inlet located below a hydrogenation component feed inlet.
3. The process according to claim 2, wherein the height of the heavy aromatic fraction feed inlet from the bottom of the catalytic cracking reactor is 0 to 1/3, preferably 0 to 1/5, more preferably 0 to 1/10 of the total height of the catalytic cracking reactor; the height of the hydrogenation component feed inlet from the bottom of the catalytic cracking reactor is 1/3 to 2/3, preferably 1/3 to 1/2, more preferably 1/3 to 2/5 of the total height of the catalytic cracking reactor.
4. The process of claim 1, wherein the raffinate oil is also introduced to the catalytic cracking unit.
5. The process according to claim 1, wherein the light aromatic fraction and the heavy aromatic fraction have a cut point of 150-190 ℃, preferably 160-180 ℃; the cutting point of the heavy aromatic fraction and the circulating oil fraction is 200-270 ℃, preferably 230-260 ℃; the cutting point of the cycle oil fraction and the heavy oil fraction is 340 to 370 ℃, preferably 350 to 360 ℃.
6. The process according to claim 1, wherein the content of C6-C8 aromatics in the light aromatic fraction is not less than 40 wt%, preferably not less than 50 wt%; the content of c9+ aromatic hydrocarbons in the heavy aromatic fraction is not less than 50 wt%, preferably not less than 70 wt%.
7. The process according to claim 1, wherein the reaction temperature of the hydrotreating unit is 350 to 450 ℃, the hydrogen partial pressure is 5 to 15MPa, the volume space velocity is 2 to 15h -1 Hydrogen oil volume ratio of 400-1600 Nm 3 /m 3 。
8. The process according to claim 1, wherein the content of polycyclic aromatic hydrocarbons in the hydrogenation component is not more than 25% by weight, preferably not more than 15% by weight.
9. The process according to claim 1, wherein the catalytic cracking reactor has a reaction temperature of 500 to 700 ℃, preferably 550 to 650 ℃, a catalyst to oil mass ratio of 1 to 60, preferably 4 to 20, an oil gas residence time of 0.2 to 10s, preferably 0.5 to 7s, and a reaction pressure (gauge pressure) of 0 to 0.2MPa, preferably 0 to 0.15MPa.
10. The process according to claim 1, wherein the aromatic extraction unit has a top temperature of 80 to 100 ℃, preferably 85 to 95 ℃, a bottom temperature of 170 to 190 ℃, preferably 175 to 185 ℃, and a pressure (gauge pressure) of 0.2 to 0.6MPa, preferably 0.4 to 0.55MPa.
11. The process according to claim 1, wherein the extraction solvent used in the aromatic hydrocarbon extraction unit is one or more of sulfolane, N-methylpyrrolidone, dimethyl sulfoxide and formylmorpholine.
12. The process according to claim 1, wherein the sum of the benzene, toluene and xylene contents of the C6-C8 light aromatics obtained by the aromatics extraction unit is not less than 95 wt%, preferably not less than 98 wt%.
13. The process of claim 1, wherein the cycle oil fraction is also introduced into the hydroprocessing unit for hydrogenation reactions; and/or the number of the groups of groups,
and introducing heavy aromatic hydrocarbon fractions generated by other devices into the catalytic cracking reactor for reaction, wherein the other devices comprise one or more of a steam cracking device, a catalytic cracking device, a hydrogenation device, a reforming device and an aromatization device.
14. The catalytic conversion process of claim 1, wherein the feedstock oil is one or more of straight run diesel, catalytically cracked light cycle oil, coker diesel, thermally cracked diesel, aromatizer diesel, coal direct liquefaction diesel, shale oil diesel.
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