Method and system for treating catalytic cracking reaction product and use thereof

Patent metadata

Field	Value
Publication number	US-12168755-B2
Application number	US-202017755489-A
Country	US
Kind code	B2
Filing date	Aug 4, 2020
Priority date	Oct 30, 2019
Publication date	Dec 17, 2024
Grant date	Dec 17, 2024

Abstract

In a method and system for treating a catalytic cracking gasoline, a catalytic cracking process, or a plant employs a fluidized reactor to carry out hydrodealkylation treatment on a catalytic cracking oil gas or catalytic cracking gasoline, so that heavy aromatics present therein can be efficiently converted into light olefins and light aromatics. The method and system can improve the yield of light olefins, allow a long-period stable operation, relieve the contradiction between supply and demand of light aromatics, and solve the problem of high content of heavy aromatics that have low value and are difficult to be utilized in aromatics present in oil gas from catalytic cracking units.

First claim

The invention claimed is:

1. A method for treating a catalytic cracking product, comprising the steps of:
feeding a first feed into a catalytic cracking reactor for catalytic cracking reaction in presence of a catalytic cracking catalyst to produce the catalytic cracking product;
carrying out a first fractionation on the catalytic cracking product to obtain a heavy gasoline and a light gasoline, wherein the light gasoline has an initial boiling point of about 20-40° C. and a final boiling point of about 80-100° C., the heavy gasoline has an initial boiling point of about 80-100° C. and a final boiling point of about 200-250° C.;
carrying out a second fractionation on a second feed to obtain a heavy fraction of gasoline and a middle fraction of gasoline, wherein the middle fraction of gasoline comprises C6-C8 light aromatics, has an initial boiling point of about 80-100° C., and a final boiling point of about 120-150° C., and the heavy fraction of gasoline comprises C9+ aromatics, has an initial boiling point of about 120-150° C., and a final boiling point of about 200-250° C.;
carrying out an aromatics extraction on the middle fraction of gasoline to obtain BTX aromatics and an aromatic raffinate oil;
sending the heavy fraction of gasoline to a fluidized reactor for dealkylation in the presence of hydrogen and a dealkylation catalyst to obtain a dealkylated liquid product and a spent dealkylation catalyst; and
wherein the first feed comprises a hydrocarbon-containing feedstock oil, the light gasoline and the aromatic raffinate oil, and
wherein the second feed comprises the heavy gasoline and the dealkylated liquid product,
wherein the catalytic cracking product comprises a catalytic cracking oil gas, and a catalytic cracking gasoline.

2. The method according to claim 1 , wherein the dealkylation is carried out at a temperature of about 250-700° C., a pressure (gauge pressure) of about 0-6 MPa, a weight hourly space velocity of about 0.1-120 h −1 or a reaction time of about 0.1-40 seconds, and a hydrogen/hydrocarbon molar ratio of about 1-14.

3. The method according to claim 1 , wherein the dealkylation catalyst comprises a carrier and an active metal component supported on the carrier, wherein the active metal component is present in an amount of about 0.01-50 wt. %, based on the total weight of the dealkylation catalyst,
wherein, based on the total weight of the carrier, the carrier comprises: about 1-80 wt % of zeolite, about 5-99 wt % of inorganic oxide, and about 0-70 wt % of clay;
wherein the zeolite comprises a mesoporous zeolite, a macroporous zeolite, or a combination thereof;
wherein the inorganic oxide is one or more selected from silica, alumina, zirconia, titania and amorphous silica-alumina; the clay is one or more selected from kaolin, montmorillonite, diatomite, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite, and
wherein the active metal component is one or more selected from rare earth metals and transition metals.

4. The method according to claim 3 , wherein the mesoporous zeolite is one or more selected from ZSM zeolites and ZRP zeolites, and the macroporous zeolite is one or more selected from β zeolites, REY zeolites, REHY zeolites, ultrastable Y zeolites and high silica Y zeolites.

5. The method according to claim 3 , wherein, based on the total weight of the zeolite, the mesoporous zeolite is present in an amount of about 0-100 wt %, and the macroporous zeolite is present in an amount of about 0-100 wt %.

6. The method according to claim 5 , wherein the mesoporous zeolite is present in an amount of from about 50-100 wt %.

7. The method according to claim 5 , wherein the mesoporous zeolite is present in an amount of from about 70-90 wt %.

8. The method according to claim 5 , wherein the macroporous zeolite is present in an amount of from about 0-50 wt %.

9. The method according to claim 5 , wherein the macroporous zeolite is present in an amount of from about 10-30 wt %.

10. The method according to claim 1 , further comprising:
sending the spent dealkylation catalyst to a fluidized bed regenerator for regeneration, and recycling the regenerated dealkylation catalyst to the fluidized reactor.

11. The method according to claim 10 , wherein the fluidized bed regenerator comprises a lock hopper, and the regeneration is carried out by:
sending the spent dealkylation catalyst to the fluidized bed regenerator for regeneration through the lock hopper, and recycling the regenerated dealkylation catalyst to the fluidized reactor through the lock hopper.

12. The method according to claim 11 , wherein the fluidized bed regenerator further comprises a reactor receiver, a regenerator receiver, a regenerator feed tank, and optionally a reducer, and the regeneration is carried out by:
withdrawing the spent dealkylation catalyst from the fluidized reactor, sending the spent dealkylation catalyst to the reactor receiver, and then to the regenerator feed tank through the lock hopper, and then transferring the spent dealkylation catalyst to the fluidized bed regenerator from the regenerator feed tank;
regenerating the spent dealkylation catalyst in the regenerator by coke burning in an oxygen-containing atmosphere to obtain the regenerated dealkylation catalyst; and
withdrawing the regenerated dealkylation catalyst from the fluidized bed regenerator, directly recycling the regenerated dealkylation catalyst to the fluidized reactor for reuse through the regenerator receiver, or recycling the regenerated dealkylation catalyst to the fluidized reactor for reuse after passing through a reducer for reduction.

13. The method according to claim 12 , wherein the method further comprises the step of depressurizing the spent catalyst in the lock hopper and the step of pressurizing the regenerated catalyst.

14. The method according to claim 1 , wherein the dealkylation is carried out at a temperature of about 320-580° C., a pressure of about 0.1-4.5 MPa, a weight hourly space velocity of about 0.5-80 h −1 or a reaction time of about 0.5-30 seconds, and a hydrogen/hydrocarbon molar ratio of about 2-11.

15. The method according to claim 1 , wherein the dealkylation is carried out at a temperature of about 350-550° C., a pressure of about 1-3.5 MPa, a weight hourly space velocity of about 1.5-50 h −1 or a reaction time of about 1-15 seconds, and a hydrogen/hydrocarbon molar ratio of about 3-6.

16. A system for carrying out the method for treating the catalytic cracking product according to claim 1 , comprising the catalytic cracking reactor, a first separation unit, a second separation unit, a dealkylation unit, and an aromatics extraction unit,
wherein the first separation unit comprises a first separator having a first oil gas inlet, a light gasoline outlet, and a heavy gasoline outlet, the first oil gas inlet is in fluid communication with the catalytic cracking reactor, and the light gasoline outlet is in fluid communication with a feedstock inlet of the catalytic cracking reactor;
the second separation unit comprises a distillate splitting column having a second oil gas inlet, an outlet for the middle fraction of gasoline and an outlet for the heavy fraction of gasoline, and the second oil gas inlet is in fluid communication with the heavy gasoline outlet;
the aromatics extraction unit comprises an aromatics extraction and separation device having a third oil gas inlet, a BTX aromatics outlet and an aromatic raffinate oil outlet, the third oil gas inlet is in fluid communication with the outlet for middle fraction of gasoline, and the aromatic raffinate oil out

Assignees

• China Petroleum & Chem Corp
• Sinopec Res Inst Petroleum

Inventors

• Wang Di
• Wei Xiaoli
• Gong Jianhong
• Yu Jingchuan
• Zhang Jiushun

Classifications

• C10G2400/30

  Aromatics · CPC title

• C10G2400/20

  C2-C4 olefins · CPC title

• C10G2300/4081

  Recycling aspects · CPC title

• C10G2300/4018

  Spatial velocity, e.g. LHSV, WHSV · CPC title

• C10G2300/4012

  Pressure · CPC title