CN1258581C - Upgrading method and system for catalytic gasoline to reduce olefins and increase octane number - Google Patents

Abstract

The present invention relates to a modification method and a system thereof for reducing the olefin content and enhancing the octane value of catalytic gasoline. In the method, an auxiliary lifting pipe reactor with an independent sedimentation and steam stripping system is additionally arranged in a reaction-regeneration system of a heavy oil catalytic cracking device; catalytic modification reaction is carried out to full fractions or heavy fractions of catalytic cracking gasoline by establishing a secondary condensing system at the tower top of a fractionating tower; modified oil gas enters a single oil gas system for carrying out the separation of modified products for reducing the olefin content and enhancing the octane value. The technology can reduce the olefin content of catalytic cracking gasoline below 35(V)%, enhances research octane values by 3 units and satisfies environment protection requirements.

Description

Upgrading method and system for catalytic gasoline to reduce olefins and increase octane number

Technical field :

The invention discloses a catalytic conversion upgrading method and system for reducing the olefin content of catalytic cracking gasoline and increasing its octane number, which belongs to the catalytic conversion process method of petroleum hydrocarbons and relates to the field of petrochemical industry.

Background technology :

In recent years, the environmental protection regulations of various countries in the world have put forward increasingly strict requirements on the quality of gasoline and diesel, especially the requirements on the olefin content, sulfur content and benzene content of gasoline have become more and more stringent. Therefore, the requirements from environmental protection have become the main driving force to promote the further development of various refining technologies, and the more traditional catalytic cracking technology is the first to bear the brunt.

The conventional catalytic cracking reaction process mainly includes the following steps: (1) The fresh raw oil is mixed with the recycled oil after heat exchange, injected from the nozzle at the lower part of the riser reactor, and mixed with the high-temperature regenerated catalyst from the regenerator in the riser reactor. Contact, then vaporize and react. The residence time of the oil and gas in the riser is very short, generally after a few seconds, it enters the settler, and the entrained catalyst is separated by the cyclone separator, and then leaves the reactor to the subsequent fractionation system. (2) The catalyst with coke, that is, the catalyst to be used, falls into the stripping section below from the settler; the stripping section is equipped with multi-layer herringbone baffles and superheated steam is introduced at the bottom, and the pores of the catalyst to be used and The oil and gas between the catalyst particles are replaced by water vapor and returned to the settler; the stripped raw catalyst enters the regenerator through the raw inclined pipe. (3) The main function of the regenerator is to burn off the carbon deposits generated by the reaction on the catalyst, so that the activity of the catalyst can be restored; the air for regeneration is supplied by the main fan, and the air enters the catalyst dense-phase bed through the distribution plate under the regenerator layer; the regenerated catalyst, that is, the regenerated catalyst, falls into the overflow pipe and is sent back to the reactor for recycling through the regenerated inclined pipe; after the entrained catalyst is separated from the regenerated flue gas by the cyclone separator, part of the energy is recovered by the smoke machine system into the atmosphere.

At present, my country's motor gasoline is still dominated by catalytic cracking gasoline, and the data show that my country's catalytic cracking gasoline accounts for as much as 90% of the finished gasoline. The volume fraction of olefins in catalytically cracked gasoline is 45% to 60%, far exceeding the gasoline standard of the new formula. Although this kind of gasoline has a high octane number, it has poor thermal stability and is easy to form colloids; after burning, it will also increase the amount of toxic substances such as active hydrocarbons and polyenes in emissions. In addition, with the continuous heavy and inferior quality of catalytic cracking raw oil, the sulfur content and nitrogen content in gasoline products are also increasing; after combustion, the emissions of SO _x and NO _x will increase, which will seriously pollute the environment.

Hydrofining is an effective measure to solve the above problems. Through hydrofining, the catalytic upgrading of oil products can be realized under hydrogen pressure, so as to achieve the purpose of desulfurization, denitrogenation, olefin saturation and aromatic saturation, so as to improve the quality of oil products and meet the requirements of Environmental requirements. However, at present, most of the domestic oil refining enterprises either lack the means of hydrofining, or the processing capacity of hydrofining is insufficient or the hydrogen source is lacking. Therefore, it is unrealistic to improve the quality of FCC gasoline, which accounts for 90% of commercial gasoline, through hydrofining, and hydrofining will bring about the loss of gasoline octane number. Other research reports mainly focus on reducing the olefin content of FCC gasoline, such as light gasoline etherification, FCC gasoline desulfurization and olefin reduction, FCC gasoline hydroisomerization aromatization, and FCC gasoline hydrodesulfurization-reforming etc. These methods and technologies are either complicated in process and large in investment, and it is still very difficult for many refineries to adopt them, or the process technology is immature and has not been industrialized.

Invention content :

The main purpose of the present invention is to provide a method and system for improving the octane number of catalytic gasoline by reducing olefins, so as to reduce the olefin content of catalytically cracked gasoline and increase the octane number of gasoline;

Another object of the present invention is to provide a method and system for catalytically reducing olefins in gasoline to increase octane number, simplify and improve the process for catalytic cracking gasoline to reduce olefins, reduce process costs, and facilitate industrialization.

The purpose of the present invention is achieved by the following methods:

A method for improving the octane number by catalytically reducing olefins in gasoline, which at least includes the following steps:

Step 1: The whole distillate or heavy distillate of naphtha enters the auxiliary upgrading riser reactor from the bottom together with water vapor, and contacts, gasifies, mixes and reacts with the high-temperature regenerant from the regenerator of the original catalytic cracking unit;

Step 2: Oil gas, water vapor and catalyst pass through the auxiliary upgrading riser reactor to the outlet of the upgrading riser reactor, and the upgraded oil gas and catalyst are separated by a high-efficiency gas-solid rapid separation device;

Step 3: The separated upgraded oil and gas enters the simple separation system to separate the rich gas and modified gasoline.

The concrete conditions of described catalytic reforming reaction are as follows:

The reaction temperature is 350-550°C;

The preheating temperature of gasoline raw material is 40-200°C;

The weight ratio of catalyst to oil is 2-20;

The catalyst activity is 55-65;

The reaction time is 2.0～10.0s;

The reaction pressure is 0.1-0.4Mpa.

The heavy fraction of the naphtha is obtained by the secondary condensation system. While obtaining the heavy fraction of catalytic cracking naphtha, the obtained naphtha light fraction can also be further upgraded.

During the upgrading process of catalytic cracking gasoline, the catalyst separated from the upgraded oil and gas enters the newly established simple settler and stripping section, and then enters the original regenerator.

For the upgrading of the whole distillate of naphtha, the gas-enriched gasoline is separated and directly enters the absorption stabilization system; for the upgrading of the heavy distillate of naphtha, the gas-enriched gasoline is mixed with the light distillate of naphtha and then enters the absorption stabilization system system.

The catalyst used in the upgrading reaction is the catalyst of the original heavy oil catalytic cracking unit, including at least amorphous silica-alumina catalyst or molecular sieve catalyst.

A upgrading system for catalytic gasoline to reduce olefins and increase octane number, which at least includes adding an auxiliary riser reaction system with an independent settling stripping system to the reaction-regeneration system of a heavy oil catalytic cracking unit, and a upgrading system connected to it. Oil and gas separation system; among them, the auxiliary riser reaction system is used for catalytic upgrading of FCC gasoline, and the upgraded oil and gas separation system is used for separating upgraded gasoline and rich gas.

The heavy oil catalytic cracking unit also includes a secondary condensing system established on the conventional condensing and cooling system at the top of the original fractionation tower, which is used to obtain the heavy fraction of naphtha, and can also obtain the whole fraction of naphtha.

The auxiliary riser reaction system is composed of a high-temperature regenerated catalyst flow inclined pipe drawn from the regenerator of the original heavy oil catalytic cracking unit and a riser reactor; the outlet part of the riser reactor enters the settling stripping system , The outlet is equipped with a high-efficiency gas-solid rapid separation device.

The modified oil-gas separation system is as follows: the top of the simple washing separation tower is connected to the condensing cooler, and the bottom of the tower is connected to the heat exchanger for removing superheated washing medium.

The desuperheated scrubbing medium in the simple scrubbing and separating tower is recycled oil or heavy diesel oil.

The technical advantages of the present invention are: since the modified gasoline enters a separate separation system and then exits the device without being mixed with the catalytically cracked gasoline in the main riser, the olefin content of the naphtha whole fraction or heavy fraction returned to the modified riser That is, the olefin content of the whole distillate or heavy distillate of naphtha coming out of the main riser, that is, the initial reaction concentration of gasoline olefins in the modified riser is relatively high, so that the required process conditions will be relatively mild, and the reforming will not be over-reacted. The components in the reforming riser reactor are circulated many times, the loss in the reforming process will be reduced, and the amount of gasoline that needs to be reformed will also be reduced.

Description of drawings :

Fig. 1 is a schematic diagram of the basic principles of the present invention;

Fig. 2 is the general flowchart of the present invention.

Specific implementation methods :

The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:

As shown in Figure 2, the operation of the original catalytic cracking reaction system remains unchanged, that is, the raw material 1 enters the main riser 2 from the bottom together with water vapor, and reacts with the high-temperature regenerant 5 stripped by the water vapor 4 from the regenerator 3 The temperature is 460-530°C, the preheating temperature of heavy oil raw material is 160-250°C, the weight ratio of catalyst to oil is 5-8, the catalyst activity is 50-65, the reaction time is 2.5-3.0s, and the reaction pressure is 0.1-0.4Mpa Contact, gasification, mixing and reaction under the condition, oil gas, water vapor and catalyst pass through the main riser reactor 2 together, and the main riser reactor outlet is separated by the high-efficiency gas-solid rapid separation device 6 and the settler top rotation 7. The reaction oil gas and the catalyst are separated, and the catalyst enters the stripping section 9 through the settler 8, and enters the original regenerator 3 after being stripped. The main reaction oil gas 10 leaves the settler 8 and enters the main fractionation tower for separation of rich gas, naphtha light fraction, naphtha heavy fraction, diesel oil, re-refined oil and oil slurry.

The process of separating the heavy fraction (with a cut point of 60-80°C) from the crude gasoline by the secondary condensation system at the top of the fractionating tower is briefly described as follows: the crude gasoline and the rich gas 27 come out from the top of the fractionating tower 28, and are condensed and cooled by the condenser 29 After reaching 50-60°C, it enters the separation tank 30 to separate oil, water and gas, and the condensed water 31 is drawn out of the separation tank 30 by the condensed water pump 32 . The condensed liquid product is the naphtha heavy fraction 33, which is extracted from the separation tank 30 through the naphtha heavy fraction pump 34, part of which is used as the top reflux 35 of the fractionating tower 28, and the other part 36 is further cooled to 40° C. through the cooler 37. If the whole fraction of naphtha is modified, at this moment valve 50 is opened, and valve 51 is closed, and naphtha heavy fraction 36 and naphtha light fraction 47 are mixed into naphtha full fraction 49 (i.e. 11) and enter the newly-established in the present invention The auxiliary riser reactor 12 for upgrading is used for upgrading; if the naphtha heavy fraction is upgraded, at this moment valve 51 is opened, valve 50 is closed, and the naphtha heavy fraction 48 (i.e. 11) can directly enter the newly-added reactor of the present invention. The reforming is carried out with the auxiliary riser reactor 12. At this time, the light gasoline 47 can be directly mixed with the reformed gasoline 25 from the newly added reforming oil-gas separation system of the present invention and enter the absorption stabilization system, or it can be carried out first. For example, after modification such as light gasoline etherification, isomerization aromatization, etc., it is mixed with the modified gasoline 25 from the newly added modified oil-gas separation system of the present invention and then enters the absorption stabilization system. The uncondensed oil and gas 38 coming out of the separation tank 30 is condensed and cooled to 40° C. by the condenser 39 and then enters the separation tank 40 for separation of oil, water and gas. The uncondensed oil and gas coming out of the separation tank 40 is rich gas 43 and enters the rich gas compressor. The condensate oil 44 separated from the separation tank between pneumatic machines is returned to the separation tank 40 . The liquid product condensed in the separation tank 40 is light gasoline 45. After being extracted by the light gasoline pump 46, it is either mixed with the heavy fraction of naphtha 36 to form a full-distillation naphtha 49 for reforming, or enters the follow-up system to mix with reformed gasoline 25 .

Referring to Figure 1 and Figure 2, naphtha 11 or naphtha is separated from the heavy fraction 11 (cut point is 60-80°C) by the secondary condensation system at the top of the fractionating tower, and enters the auxiliary upgrading riser from the bottom together with water vapor The reactor 12, and the high-temperature regenerant 14 raised by the steam 13 from the regenerator 3 of the original catalytic cracking unit have a reaction temperature of 350-550°C, a gasoline raw material preheating temperature of 40-200°C, and a catalyst-to-oil weight ratio of 2 ～20, the catalyst activity is 55～65, the reaction time is 2.0～10.0s, and the reaction pressure is 0.1～0.4Mpa, contact, gasify, mix and react, and the oil gas, water vapor and catalyst will be upgraded through auxiliary modification From the tube reactor 12 to the outlet of the reforming riser reactor, a high-efficiency gas-solid rapid separation device 15 separates the reformed oil and gas from the catalyst. The catalyst enters the new settler 16 and the stripping section 17, and enters the original regenerator 3 after stripping. The upgraded oil and gas 18 leave the settler 16 and enter the upgraded oil and gas separation system consisting of a washing separation tower 19, a condensing cooler 20, an oil and gas separation tank 21, a heat exchanger 22 for removing superheated washing medium, and a circulating pump 23, and separate the rich gas 24 and reformed gasoline 25. If the whole fraction of catalytic cracked naphtha is modified, the modified gasoline 25 can directly enter the absorption stabilization system; 47 (this part can also be modified, such as etherification, isomerization aromatization, etc.) and then enter the absorption stabilization system after mixing. At the bottom of the washing separation tower 19, the desuperheated scrubbing medium heat exchanger 22 and circulation pump 23 desuperheat the overheated modified oil gas and wash the catalyst powder. 26 is the desuperheated scrubbing medium carrying a small amount of modified heavy components, which can be recycled Refined oil or heavy diesel oil.

The catalyst used in the present invention can be any catalyst suitable for the catalytic cracking process, that is, the catalytic cracking gasoline upgrading reaction is realized by the catalyst of the original heavy oil catalytic cracking unit. For example, an amorphous silica-alumina catalyst or a molecular sieve catalyst; wherein, the active component of the molecular sieve catalyst is selected from Y-type or HY-type zeolite containing or not containing rare earth and/or phosphorus, ultrastable zeolite containing or not containing rare earth and/or phosphorus One or more of Y-type zeolite, ZSM-5 series zeolite or silica zeolite with five-membered ring structure, beta zeolite, ferrierite.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent replacements of the technical solutions without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the scope of the claims of the present invention.

Claims (9)

1, a kind of upgrading method that catalytic gasoline reduces olefin and improves octane number, it is characterized in that: it comprises the following steps at least: Step 1: The whole distillate or heavy distillate of naphtha enters the auxiliary upgrading riser reactor from the bottom together with water vapor, contacts, gasifies, mixes and reacts with the high-temperature regenerant from the regenerator of the original catalytic cracking unit, and the The auxiliary upgrading riser reactor is composed of a high-temperature regenerated catalyst stream inclined pipe drawn from the regenerator of the original heavy oil catalytic cracking unit and a riser reactor; the outlet part of the riser reactor enters the settling stripping system , the outlet is provided with a high-efficiency gas-solid rapid separation device; the specific conditions of the reaction are as follows: The reaction temperature is 350-550°C; The preheating temperature of gasoline raw material is 40-200°C; The weight ratio of catalyst to oil is 2-20; The catalyst activity is 55-65; The reaction time is 2.0～10.0s; The reaction pressure is 0.1-0.4Mpa; Step 2: Oil gas, water vapor and catalyst pass through the auxiliary upgrading riser reactor to the outlet of the upgrading riser reactor, and the upgraded oil gas and catalyst are separated by a high-efficiency gas-solid rapid separation device; Step 3: The separated modified oil and gas enters a simple separation system to separate rich gas and modified gasoline. The simple separation system is: the top of the simple washing separation tower is connected to a condensing cooler, and the bottom of the tower is exchanged with the desuperheated washing medium. Heater connected. 2. A method for upgrading gasoline by catalytically reducing olefins and increasing octane number according to claim 1, characterized in that: the heavy fraction of naphtha is obtained by a secondary condensing system. While obtaining the heavy fraction of catalytic cracking naphtha, the obtained naphtha light fraction is also further improved. 3. A method for upgrading catalytic gasoline to reduce olefins and increase octane number according to claim 1, characterized in that: during the upgrading process of catalytic cracked gasoline, the catalyst separated from the upgraded oil and gas enters the newly established simple settler And the stripping section enters the original regenerator. 4. A method for upgrading catalytic gasoline to reduce olefins and increase octane number according to claim 1, characterized in that: for upgrading the whole distillate of naphtha, the separated gas-rich modified gasoline directly enters the absorption and stabilization system ; For the upgrading of the heavy fraction of naphtha, the gas-rich modified gasoline is separated and mixed with the light fraction of naphtha and then enters the absorption stabilization system. 5. A method for upgrading catalytic gasoline to reduce olefins and increase octane number according to claim 1, characterized in that: the catalyst used in the upgrading reaction is the catalyst of the original heavy oil catalytic cracking unit, at least including Shaped silica-alumina catalyst or molecular sieve catalyst. 6. A upgrading system for catalytic gasoline to reduce olefins and increase octane number, characterized in that it at least includes, in the reaction-regeneration system of the heavy oil catalytic cracking unit, adding an auxiliary riser reaction system with an independent settling stripping system, And the upgraded oil-gas separation system connected with it; wherein, the auxiliary riser reaction system is composed of a high-temperature regenerated catalyst stream inclined pipe drawn from the regenerator of the original heavy oil catalytic cracking unit and a riser reactor; The outlet part of the tube reactor enters the settling stripping system, and the outlet is equipped with a high-efficiency gas-solid rapid separation device. The auxiliary riser reaction system is used for catalytic upgrading of catalytically cracked gasoline; the modified oil-gas separation system is: simple washing and separation The top of the tower is connected to a condensing cooler, and the bottom of the tower is connected to a heat exchanger for removing superheated scrubbing medium. This modified oil-gas separation system is used to separate modified gasoline and rich gas. 7. A upgrading system for catalytically reducing olefins in gasoline and increasing octane number according to claim 6, characterized in that: the specific conditions of the catalytic upgrading reaction are as follows: The reaction temperature is 350-550°C; The preheating temperature of gasoline raw material is 40-200°C; The weight ratio of catalyst to oil is 2-20; The catalyst activity is 55-65; The reaction time is 2.0～10.0s; The reaction pressure is 0.1-0.4Mpa. 8. A upgrading system for catalytic gasoline to reduce olefins and increase octane number according to claim 6, characterized in that: the heavy oil catalytic cracking unit also includes a conventional condensing cooling system on the top of the original fractionation tower The established secondary condensation system is used to obtain the heavy fraction of naphtha or the whole fraction of naphtha. 9. The upgrading system for catalytic gasoline to reduce olefins and increase octane number according to claim 6, characterized in that: the desuperheated washing medium in the simple washing and separating tower is recycled oil or heavy diesel oil.

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