CN101191068A - A kind of hydrocarbon oil cracking method - Google Patents

Abstract

A hydrocarbon oil cracking method comprises that in a riser reactor including a plurality of reaction zones, under cracking reaction conditions, the hydrocarbon oil raw material and the cracking catalyst are contacted and reacted in each reaction zone, and the catalyst and the reaction product are separated to obtain cracking product and spent catalyst, regenerating at least part of the spent catalyst to obtain a semi-regenerated catalyst and a regenerated catalyst, wherein the plurality of reaction zones includes at least one central reaction zone and at least one upper reaction zone, the upper reaction zone being located above the central reaction zone ; In the middle reaction zone, introduce inferior heavy raw material and semi-regenerated catalyst, make inferior heavy raw material and semi-regenerated catalyst contact; In the upper reaction zone, introduce heavy raw material and regenerated catalyst, make heavy raw material and regenerated catalyst contact. At least one of the residual carbon content, nickel and vanadium content, asphaltene content and basic nitrogen content of the inferior heavy raw material is higher than the heavy raw material. The method can optimize hydrocarbon oil cracking conditions and improve product distribution.

Description

A kind of hydrocarbon oil cracking method

technical field

The invention relates to a method for cracking hydrocarbon oil.

Background technique

Catalytic cracking is one of the important means of petroleum secondary processing, which is used to produce gasoline, diesel, liquefied petroleum gas, etc. from heavy crude oil. Modern catalytic cracking processes use molecular sieve catalysts and the reaction/regeneration process is continuous. The raw oil is atomized with water vapor and sprayed into the riser reactor, where it contacts with the high-temperature catalyst (550-700°C) from the regenerator, and then undergoes cracking reaction. The residence time of the oil and gas generated by the cracking reaction in the riser reactor is very short, generally only a few seconds. The reaction product leaving the riser reactor is separated from entrained catalyst in a settler, and then goes to a fractionation column for product separation. The catalyst with coke (called spent catalyst) falls from the settler into the stripping section below, and the oil gas adsorbed on the catalyst is evaporated in the stripping section. After being stripped, the spent catalyst enters the regenerator, and in the regenerator, the carbon deposit generated by the reaction on the catalyst is burned off, so that the activity of the catalyst can be restored. The regenerated catalyst is recycled.

In the early days of catalytic cracking, vacuum distillate oil was used as raw material. As crude oil became heavier and inferior, and the demand for light oil products increased, the sources of raw materials for catalytic cracking processing also expanded, such as blending vacuum residue and thermal oil. Processed products such as coking wax oil, visbreaking distillate oil, and the proportion of slag doping is also increasing, the properties of catalytic cracking raw materials are deteriorating, resulting in increased coke formation in catalytic reactions, a corresponding increase in regeneration temperature, increased thermal cracking reactions, and dry gas production. The rate and coke yield increase, and the product distribution becomes worse. At the same time, under the heating condition of the regenerator, too high temperature will accelerate the deactivation of the molecular sieve catalyst, so the temperature of the regenerator should be properly controlled.

In order to improve the contact environment between catalytic cracking catalysts and raw materials, CN1114676C and CN1114677C disclose a regeneration catalyst cooling and cooling method for optimizing the operation of the reaction system in the heavy oil catalytic cracking process. Mixing in the pre-lift section of the tube or riser reactor creates a "three-high" operating condition of high regeneration temperature, high catalyst-to-oil weight ratio (that is, the ratio of catalyst to feedstock oil), and high feedstock preheating temperature, which can improve The slagging ratio of the device can increase the conversion rate and light oil yield, and improve product distribution, but the high regeneration temperature of this method is not conducive to maintaining the activity of the catalyst. US5451313 developed the mixing technology of the spent catalyst and the regenerated catalyst, and US6059958 developed the mixing technology of the regenerated catalyst and the cooled regenerated catalyst.

CN1340593A discloses a catalytic cracking oil agent contact method. An oil agent distributor is arranged between the pre-lift medium inlet inside the riser reactor and the main raw material inlet, and the lower part of the riser reactor is divided into parallel to the axial direction. 2-4 reaction zones, and corresponding catalyst inlets and pre-upgrading raw material nozzles are set in each reaction zone; high-temperature regenerated agent from the regenerator, cooled semi-regenerated agent and/or spent agent from the stripping section Enter different reaction zones respectively; the pre-modified raw materials are injected into one, two or three reaction zones, contact and react with the catalyst in the reaction zone; the reacted stream and the catalyst not participating in the reaction in other reaction zones Go up the riser reactor in their respective reaction zones, meet at the outlet of the oil agent distributor, contact and react with the main raw material that has been atomized by steam; separate the reaction products, and carry out gas stripping and regeneration of the raw agent, so that The above-mentioned oil agent contact process is carried out cyclically. In this method, raw materials with different properties enter each reaction zone to contact with catalysts with different temperatures and carbon contents for modification, which plays a pretreatment role for heavy raw materials and can improve product distribution. But the liquid yield of this method is low.

CN1088246A discloses a catalytic cracking method for high-nitrogen feedstock oil. In this method, high-quality feedstock oil is injected from the bottom of the reactor and contacted with fresh regenerated catalyst under suitable conditions. The high-nitrogen feedstock oil is injected from a certain part in the middle of the reactor , contact with the catalyst with carbon that rises along the reactor after cracking high-quality raw oil, and then through separation, fractionation, stripping, regeneration, the specific operation steps are as follows: (1) make the hydrogen content higher than 11% by weight, nitrogen content Less than 2500ppm (weight) or basic nitrogen content less than 1000ppm (weight) high-quality raw material oil is injected from the bottom of the riser reactor, and comes into contact with the high-temperature regenerated catalyst from the regenerator, and the catalyst mixture of oil gas and deposited coke generated by the cracking reaction flows along the riser The reactor moves upwards, the amount of high-quality raw material oil added accounts for 20-95% by weight of the total feed amount, operating conditions: temperature 450-600°C, agent-oil weight ratio 4-30, pressure 0.1-0.5MPa, oil gas The contact time with the catalyst is 0.2-15 seconds; (2) the high-nitrogen feed oil with a nitrogen content greater than 2000ppm (weight) or a basic nitrogen content greater than 1000ppm (weight) is removed from the 1/4-3/4 of the bottom of the riser reactor Injection at the position where it is in contact with the mixture of oil gas and carbon catalyst moving upwards, the addition of the high-nitrogen feedstock oil accounts for 5-80% by weight of the total feed amount, operating conditions: temperature 450-600 ° C, agent oil weight Ratio 2-20, pressure 0.1-0.5MPa, oil gas and catalyst contact time 0.1-15 seconds; (3) The mixture of total oil gas and carbon catalyst generated from step (2) enters the separator to effectively separate catalyst and oil gas Components; (4) The oil and gas separated from step (3) enters a fractionation tower, and the low molecular weight components and unreacted raw oil are fractionated, wherein heavy oil and/or clarified oil can be recycled into step (1) or step (2 ) back to refining. (5) the band carbon catalyst separated from step (3) enters the stripper, removes entrainment and hydrocarbons adsorbed on the band carbon catalyst with the stripping gas comprising water vapor; (6) strips from step (5) The final deactivated catalyst enters the regenerator for coke regeneration, and the regenerated catalyst circulates to step (1) to contact with high-quality raw material oil. The process has a lower liquid yield and a higher dry gas and coke yield.

Contents of the invention

The purpose of the present invention is to provide a hydrocarbon oil cracking method with higher liquid yield and lower yield of dry gas and coke in order to overcome the shortcomings of low liquid yield and high yield of dry gas and coke in the existing hydrocarbon oil cracking method .

The invention provides a method for contacting a catalytic cracking oil agent. The method comprises that in a riser reactor including a plurality of reaction zones, under cracking reaction conditions, the hydrocarbon oil raw material and the cracking catalyst are contacted and reacted in each reaction zone, Separating the catalyst from the reaction product to obtain cracked products and spent catalyst, regenerating at least part of the spent catalyst to obtain semi-regenerated catalyst and regenerated catalyst, wherein the plurality of reaction zones includes at least one middle reaction zone and at least one upper reaction zone zone, the upper reaction zone is located above the middle reaction zone; in the middle reaction zone, the inferior heavy raw material and semi-regenerated catalyst are introduced to contact the inferior heavy raw material and the semi-regenerated catalyst; in the upper reaction zone, the heavy The raw material and the regenerated catalyst are used to contact the heavy raw material with the regenerated catalyst; at least one of the carbon residue content, the content of metal nickel and vanadium, the asphaltene content and the basic nitrogen content of the inferior heavy raw material is higher than that of the heavy raw material. quality raw materials.

The catalytic cracking oil agent contact method provided by the invention has the following advantages:

1. In the present invention, the riser reactor is divided into multiple reaction zones, and heavy and inferior raw materials and heavy raw materials are contacted with semi-regenerated catalysts and regenerated catalysts in different reaction zones of the riser reactor to react respectively, thereby optimizing the reaction environment, and obviously The yield of liquid products is increased, and the yield of dry gas and coke is reduced. For example, compared with the prior art of not carrying out partition feeding and adding different catalysts, the yield of liquefied gas is increased by 0.89% by weight, wherein the content of propylene is increased by 0.85% by weight, the yield of diesel oil is increased by 1.37% by weight, The yield of liquefied gas+C5+gasoline+diesel increased by 1.61% by weight, the yield of dry gas decreased by 0.76% by weight, and the yield of coke decreased by 0.92% by weight.

2. In the middle reaction zone, the introduced semi-regenerated catalyst and inferior heavy raw material contact and react in this reaction zone, and the basic nitrogen, asphaltenes and heavy metals in the inferior heavy raw material are adsorbed, and at the same time due to the semi-regenerated catalyst The activity is weak, thus avoiding the increase of coke yield caused by violent reaction, which is beneficial to optimize the quality of the product and reduce the coke yield. At the same time, since the adsorption process is an endothermic process, the temperature of the reactant stream can be lowered, so when the reactant stream rises to the upper reaction zone and contacts the high-temperature regenerated catalyst, the temperature of the catalyst can be lowered, thereby reducing the temperature of the cracking reaction, thereby reducing The yields of dry gas and coke were determined.

The present invention also preferably adds a lower reaction zone, in which the light raw material is contacted with a spent catalyst or a semi-regenerated catalyst to modify the light raw material, which can reduce the sulfur content and olefin content in the light raw material, And can increase the yield of propylene. For example, compared with the prior art without light feedstock upgrading, the sulfur content of gasoline is reduced by 0.016% by weight, the content of olefins is reduced by 5% by volume, the content of aromatics is increased by 3.8% by volume, and the content of isoparaffins is increased up to 12.3% by volume.

The method provided by the present invention can also appropriately change the operating conditions of each reaction zone by increasing or decreasing the number of a certain reaction zone according to the demand, such as adjusting the reaction temperature, the weight ratio of the agent to oil and the reaction time, etc., to obtain different purpose product. For example, by increasing the number of the middle reaction zone and the upper reaction zone, the temperature of the middle reaction zone and the upper reaction zone can be increased to increase the production of liquefied gas and gasoline; the production of liquefied gas can be reduced by reducing the temperature of the middle reaction zone and the upper reaction zone , producing the most gasoline and/or diesel.

Description of drawings

Fig. 1 is a schematic structural diagram of a riser reactor reaction system for catalytic cracking in the present invention.

Detailed ways

The catalytic cracking method provided by the present invention comprises, in a riser reactor including a plurality of reaction zones, under cracking reaction conditions, contacting and reacting the hydrocarbon oil raw material and the cracking catalyst in each reaction zone, separating the catalyst and the reaction product, Obtain the cracked product and spent catalyst, regenerate at least part of the spent catalyst to obtain semi-regenerated catalyst and regenerated catalyst, wherein the plurality of reaction zones include at least one middle reaction zone and at least one upper reaction zone, and the upper reaction zone is located in the middle Above the reaction zone; In the middle reaction zone, introduce inferior heavy raw material and semi-regenerated catalyst, make inferior heavy raw material and semi-regenerated catalyst contact; In the described upper reaction zone, introduce heavy raw material and regenerated catalyst, make heavy The low-quality raw material is in contact with the regenerated catalyst; at least one of the carbon residue content, nickel and vanadium content, asphaltene content and basic nitrogen content of the poor-quality heavy raw material is higher than that of the heavy raw material.

In a preferred embodiment of the present invention, the number of the middle reaction zone and the number of the upper reaction zone is one each.

In the method provided by the invention, the volume ratio of the middle reaction zone and the upper reaction zone can be arbitrary, as long as such two reaction zones are included and the aforementioned raw materials and catalysts are introduced into the corresponding reaction zones, the present invention can be achieved Purpose. Preferably, the volume ratio of the middle reaction zone to the upper reaction zone is 1: 2-10, and the diameters of each reaction zone of the riser reactor can be the same or different. When the diameters of each reaction zone of the riser reactor are the same At the same time, the height ratio of the middle reaction zone to the upper reaction zone is the volume ratio. Therefore, when the diameters of each reaction zone of the riser reactor are the same, the height ratio of the middle reaction zone to the upper reaction zone is preferably 1: 2-10 .

In the method provided by the present invention, the cracking reaction conditions in each reaction zone can be conventional cracking conditions, preferably, in the middle reaction zone, the cracking conditions include the contact temperature of inferior heavy raw material and semi-regenerated catalyst The temperature is 400-650°C, preferably 450-550°C, the contact pressure is 130-450 kPa, preferably 200-400 kPa, the weight ratio of semi-regenerated catalyst to inferior heavy raw material is 2-15:1, preferably 3 -10:1, the weight hourly space velocity of inferior heavy raw materials is 1-120 hours ^-1 , preferably 2-80 hours ^-1 , the weight ratio of pre-lift medium to inferior heavy raw materials is 0.01-0.1:1, preferably 0.03- 0.08:1; in the upper reaction zone, the contact temperature between the heavy raw material and the regenerated catalyst is 400-650°C, preferably 500-600°C, and the contact pressure is 130-450 kPa, preferably 150-250 kPa, the heavy The agent-oil weight ratio of the raw material to the regenerated catalyst is 2-15:1, preferably 3-10:1, the weight hourly space velocity of the heavy raw material is 1-120 hours ^-1 , preferably 2-60 hours ^-1 , the pre-lifting medium and The weight ratio of heavy raw materials is 0.01-0.1:1, preferably 0.03-0.08:1.

The conditions in the outlet zone of the riser reactor are conventional conditions, these conditions include a temperature of 460-590°C, preferably 470-550°C, and a contact time of 0.1-1 second, preferably 0.1-0.8 second. Conditions in the exit zone of a riser reactor are well known to those skilled in the art.

At least one of the residual carbon content, nickel and vanadium content, asphaltene content or basic nitrogen content of the inferior heavy raw material is higher than that of the heavy raw material. Preferably, one or more of the residual carbon content, metal nickel and vanadium content, asphaltene content and basic nitrogen content of the inferior heavy raw material meet the following conditions: the residual carbon content is greater than 5% by weight, Preferably 6-15 wt%, the content of metallic nickel and vanadium is greater than 5 wtppm, preferably 7-20 wtppm, the content of asphaltene is greater than 1 wt%, preferably 3-10 wt%, the content of basic nitrogen is greater than 800ppm, preferably 1000 -2000ppm.

Preferably, one or more of the heavy raw material's carbon residue content, metal nickel and vanadium content, asphaltene content or basic nitrogen content meets the following conditions: the carbon residue content is less than 5% by weight, preferably Less than 3% by weight, the content of metallic nickel and vanadium is less than 5% by weight, preferably less than 3% by weight, the content of asphaltene is less than 1% by weight, preferably less than 0.8% by weight, and the content of basic nitrogen is less than 800ppm, preferably less than 500ppm.

The inferior heavy raw material can be one of coker wax oil (distillation range is 350-500°C), atmospheric residue (distillation range> 350°C), vacuum residue (distillation range> 500°C) or several. The basic nitrogen content of coking wax oil is relatively high, generally greater than 1000ppm (weight), and the content of metal nickel, vanadium, asphaltenes and residual carbon in atmospheric residue oil and vacuum residue oil is relatively high, and the hydrogen content is low, such as Daqing The carbon residue content of the vacuum residue is 8% by weight, the asphaltene content is 0.6% by weight, and the nickel metal content is 8.8ppm (weight). Preferably, the heavy raw material is a hydrocarbon oil with better quality than the inferior heavy raw material, and one or more of its carbon residue content, metallic nickel content, metallic vanadium content, asphaltene content and basic nitrogen content are low The inferior heavy raw material can be straight run wax oil (distillation range is 250-350°C), vacuum gas oil (distillation range is 350-500°C), hydrocracking tail oil (distillation range is 250-450°C) °C), solvent deasphalted oil (distillation range > 350 °C) or hydrorefined oil (distillation range > 350 °C).

In a preferred embodiment of the present invention, the multiple reaction zones also include at least one lower reaction zone, the lower reaction zone is located below the middle reaction zone, and in the lower reaction zone, light raw materials and spent catalyst or Semi-regenerated catalysts, where light feedstocks are contacted with spent or semi-regenerated catalysts.

According to the method provided by the present invention, the reactor includes a plurality of reaction zones, and the number of the reaction zones can be increased or decreased according to different needs, and the number of the reaction zones is preferably 2-5, more preferably 3 , namely a lower reaction zone, a middle reaction zone and an upper reaction zone.

In the method provided by the invention, the volume ratio of the middle reaction zone and the lower reaction zone can be arbitrary, as long as such two reaction zones are included and the aforementioned raw materials and catalysts are introduced into the corresponding reaction zones, the present invention can be achieved. Purpose. Preferably, the volume ratio of the middle reaction zone to the lower reaction zone is 1:0.5-2. The diameters of the middle reaction zone and the lower reaction zone of the riser reactor can be the same or different. When the diameters of the middle reaction zone and the lower reaction zone are the same, the height ratio of the middle reaction zone to the lower reaction zone is the volume ratio. Therefore, when the diameters of the middle reaction zone and the lower reaction zone of the riser reactor are the same, the height ratio of the middle reaction zone to the lower reaction zone is 1:0.5-2.

In the present invention, in the lower reaction zone provided at the lower part of the above-mentioned riser reactor, the light raw material is contacted with the spent catalyst or the semi-regenerated catalyst to upgrade the light raw material. Upgrading the light raw material can reduce the sulfur content and olefin content in the light raw material, and can increase the yield of propylene.

In a preferred embodiment provided by the present invention, the cracking reaction conditions in the lower reaction zone are conventional cracking conditions. The contact temperature of the semi-regenerated catalyst and the light raw material is 300-600°C, preferably 350-500°C, the contact pressure is 200-500 kPa, preferably 250-400 kPa, the spent catalyst or the cooled semi-regenerated catalyst from the catalyst cooler The weight ratio of catalyst to light raw material to oil is 2-15:1, preferably 3-10:1, the weight hourly space velocity of light raw material is 1-120 h ^-1 , preferably 4-50 h ^-1 , the pre-lifting medium The weight ratio to light raw material is 0.005-0.1:1, preferably 0.01-0.05:1.

In the present invention, the light raw material is a hydrocarbon raw material with a distillation range of 20-250°C, such as one or more of coking gasoline, straight-run gasoline, catalytic gasoline, thermally cracked gasoline, and reformed raffinate.

In the above method of the present invention, the pre-lift medium can be various pre-lift mediums well known to those skilled in the art, such as one or more of steam, refinery dry gas, light alkanes, and light olefins. The role of the pre-lift medium is to accelerate the rise of the catalyst to form a catalyst plug flow with uniform density at the bottom of the riser reactor. The amount of pre-lift medium used is known to those skilled in the art. Generally, the amount of pre-lift medium is 1-30% by weight, preferably 2-15% by weight, of the total amount of hydrocarbon oil.

The cracking catalyst in the present invention can be various cracking catalysts, such as amorphous silica-alumina cracking catalyst or zeolite-containing cracking catalyst, and the composition of the cracking catalyst is well known to those skilled in the art. For example, the zeolite-containing cracking catalyst generally contains one or more molecular sieves containing or not containing rare earth elements, refractory inorganic oxides, and optionally clay, the content of molecular sieves, refractory inorganic oxides and clay is Known to those skilled in the art.

The molecular sieve containing or not containing rare earth elements can be various zeolites and/or non-zeolite molecular sieves used as active components of cracking catalysts, such as Y-type zeolite containing or not containing rare earth elements, ultrafine zeolite containing or not containing rare earth elements One or more of stable Y-type zeolite, high-silica zeolite with five-membered ring structure, beta zeolite, mordenite, and omega zeolite, and high-silica zeolite with five-membered ring structure can be ZSM-5 zeolite and/or ZRP Zeolite.

The heat-resistant inorganic oxides are well known to those skilled in the art, such as one or more selected from alumina, silicon oxide, amorphous silica-alumina, zirconia, titanium oxide, boron oxide, and alkaline earth metal oxides .

Described clay is well known to those skilled in the art, as can be selected from kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, saponite, cumulated clay, sepiolite, attapulgite, hydrotalcite , One or more of bentonite.

The spent catalyst described herein is the catalyst that is stripped by the stripping section after the completion of the catalytic cracking reaction, and the carbon content of the spent catalyst is about 0.8-1.2% by weight. A semi-regenerated catalyst is an incompletely regenerated catalyst, which refers to a regenerated catalyst with a carbon content of about 0.16-0.48% by weight, such as a catalyst obtained from a first-stage regenerator in a two-stage regenerator. A regenerated catalyst is a fully regenerated catalyst having a carbon content of about 0.01-0.05% by weight, such as catalyst obtained from a second stage regenerator in a two stage regenerator.

Methods for obtaining semi-regenerated catalysts and regenerated catalysts are known to those skilled in the art. For example, the two-stage regeneration system disclosed in CN1221022A can be used for regeneration. The system includes two regenerators arranged overlappingly. The flow sequence of the regeneration method is that the first regenerator is at the upper part, and the second regenerator is at the lower part. The two regenerators are connected as a whole with a low-pressure drop distribution plate to maintain The operating pressure and operating temperature required by the two regenerators will burn the coke-deposited catalyst to meet the requirements for catalyst activity recovery; the flue gas from the second regenerator enters the first regenerator through a low-pressure drop distribution plate to ensure The dense-phase bed of the first regenerator is fluidized; the first regenerator supplies air through the main air pipe and distributes it with a distribution ring; the two-stage regeneration has only one flue and a double-action slide valve or butterfly valve, that is, only one stage of regeneration produces The flue gas is discharged from the flue.

In this patent, the specific process engineering and operating conditions of the overlapping two-stage regeneration of heavy oil fluidized catalytic cracking are as follows: from the inclined tube of the raw catalyst to the riser reactor, the processed carbon containing 4-10 wt% The raw catalyst with a carbon content of 0.8-1.2% by weight is fed into the upper part of the first-stage regenerator, and the lower part of the first-stage regenerator is fed with oxygen-containing gas (generally air) as The combustion gas is used for charring, and the flue gas containing 5-7 vol% of excess oxygen discharged from the second-stage regenerator enters the bottom of the first-stage regenerator through the distribution plate, and is used as combustion gas for charring. The first-stage regenerator flue gas containing excess oxygen of 0-0.4 vol% is discharged from the flue of the first-stage regenerator and sent to the carbon monoxide boiler. The temperature in the first-stage regenerator is 660-690°C, and the top pressure is 140-260 kPa (gauge pressure). The scorched amount of the device is 60-80% by weight, and the hydrogen is almost completely burned off. The semi-regenerated catalyst is obtained in the lower part of the first-stage regenerator, and the semi-regenerated catalyst is sent to the lower part of the second-stage regenerator from the inclined pipe of the semi-regenerated agent. A large stream of oxygen-containing gas (usually air) is sent from the oxygen-containing gas pipeline to the bottom of the second-stage regenerator, and is fluidized and burnt through the gas distributor. The flue gas is sent to the first-stage regenerator through the distribution plate to be used as a combustion gas for regenerating charred. The pressure drop across the distribution plate is 0.9-3 kPa. The temperature inside the second stage regenerator is 660-760°C, and the top pressure is 170-290 kPa (gauge pressure). The amount of coke on the catalyst burned off by the second-stage regenerator is 40-20% by weight. When the regeneration heat of the first stage and the second stage is unbalanced, a part of the semi-regenerated catalyst is discharged from the lower part of the first stage regenerator, and sent to the external heat collector through the pipeline for heat extraction. The pressure-regulating gas (usually air) is sent from the gas supply pipe to the lower part of the external heat extractor, the cooled semi-regenerated catalyst is sent to the second-stage regenerator through the pipeline, and the pressure-regulating gas escapes into the first-stage regenerator through the pipeline. The regenerated catalyst in the second-stage regenerator has a carbon content of 0.01-0.05% by weight, and is sent to the riser reactor through the inclined tube of the regenerated catalyst for use in catalytic cracking reaction.

According to the first preferred embodiment of the present invention: the preheated inferior heavy raw material enters the middle reaction zone through the atomizing nozzle, contacts with the cooling semi-regenerated catalyst from the catalyst cooler, and the inferior heavy raw material is adsorbed and reacted, and then Under the action of the pre-lifting medium, it rises along the riser reactor, mixes with the high-temperature catalyst from the regenerator entering the upper reaction zone and the preheated heavy raw material, and contacts and reacts. The reaction from the middle reaction zone and the upper reaction zone The stream continues to rise along the riser reactor, enters the settler after reaching the outlet of the riser reactor, separates the catalyst and the reaction product, and the catalyst is stripped by the stripper to obtain the unborn catalyst, and the semi-regenerated catalyst and To regenerate the catalyst, recycle part of the unused catalyst, part of the semi-regenerated catalyst and the regenerated catalyst, and the reaction product enters the subsequent product separation equipment.

According to the second preferred embodiment of the present invention: the preheated light raw material enters the lower reaction zone through the atomizing nozzle, and contacts with the waiting catalyst or semi-regenerated catalyst from the stripper, and the light raw material is carried out through adsorption and reaction. Upgrading, the reactant flow rises along the riser reactor under the action of the pre-lifting medium, and mixes with the preheated inferior heavy raw material and semi-regenerated catalyst entering the middle reaction zone through the atomizing nozzle, and the inferior heavy raw material and semi-regenerated catalyst The catalyst contacts and reacts, and the reactant flow continues to rise along the riser reactor to mix, contact and react with the high-temperature catalyst and heavy raw materials from the regenerator, and the reactant flow from the lower reaction zone, middle reaction zone and upper reaction zone continues to rise The tube reactor rises and enters the settler after reaching the outlet of the riser reactor to separate the catalyst and the reaction product. The catalyst is stripped by the stripper to obtain the raw catalyst, and the semi-regenerated catalyst and the regenerated catalyst are obtained according to the method of the above-mentioned patent CN1221022A. The spent catalyst, partially regenerated catalyst and regenerated catalyst are recycled, and the reaction product enters the subsequent product separation equipment.

The preferred catalytic cracking reaction process of the present invention will be described below with reference to FIG. 1 . The two-stage regeneration method of the catalyst has been disclosed in many documents, and the above-mentioned Chinese patent CN1221022A can be referred to here. The preheated light feedstock enters the bottom of the lower reaction zone 1 through the atomizing nozzle 7 of the riser reactor, while the spent catalyst from the stripper and/or the semi-regenerated catalyst from the two-stage regenerator are reacted through the riser The catalyst inlet 4 of the reactor enters the bottom of the lower reaction zone 1, and under the lifting action of the pre-lifting medium entering the bottom of the riser reactor through the pipeline 10, the spent catalyst and/or semi-regenerated catalyst and light raw materials are lifted along the riser The reactor rises and contacts the reaction in the lower reaction zone 1, after which the reactant stream from the lower reaction zone 1 enters the middle reaction zone 2.

The preheated inferior heavy raw material enters the middle reaction zone 2 through the atomization nozzle 8 of the riser reactor, and the semi-regenerated catalyst from the two-stage regenerator enters the middle reaction zone 2 through the catalyst inlet 5 of the riser reactor. The heavy raw material, the semi-regenerated catalyst and the reactant flow from the lower reaction zone 1 are mixed and contacted in the middle reaction zone 2; after that, the reactant flow in the middle reaction zone 2 enters the upper reaction zone 3.

The preheated heavy raw material enters the upper reaction zone 3 through the atomizing nozzle 9 of the riser reactor, while the regenerated catalyst from the two-stage regenerator enters the upper reaction zone 3 through the catalyst inlet 6 of the riser reactor. The raw material, the regenerated catalyst and the reactant flow from the middle reaction zone 2 are mixed and contacted in the upper reaction zone 3. After that, the reactant flow in the upper reaction zone 3 continues to rise along the riser reactor, and enters the sedimentation after reaching the outlet of the riser reactor The catalyst is separated from the catalyst and the reaction product. The catalyst is stripped by the stripper to obtain the unused catalyst. According to the method of the above-mentioned patent CN1221022A, the semi-regenerated catalyst and the regenerated catalyst are obtained, and the unregenerated catalyst, the semi-regenerated catalyst and the regenerated catalyst are recycled. The reaction product Enter the subsequent product separation equipment.

In the above method of the present invention, steam is used for stripping in the stripper, and its function is to replace the oil and gas filled between the catalyst particles and in the pores of the particles, so as to increase the oil product yield. The amount of steam used for stripping is known to those skilled in the art. Generally, the amount of steam used for stripping is 0.1-0.8% by weight, preferably 0.2-0.4% by weight, of the catalyst circulation.

Because the catalyst will be lost after a period of time circulation, therefore, it is necessary to replenish the fresh catalyst regularly or irregularly, and the fresh catalyst is mixed with the regenerated catalyst for use, and the ratio and method of replenishing the fresh catalyst are well known to those skilled in the art .

The present invention will be described in further detail in the form of embodiments in conjunction with the accompanying drawings, but it should not be considered as a limitation to the protection scope of the present invention. In the examples, unless otherwise specified, the heat exchangers used are shell-and-tube heat exchangers, and the regenerators used are two-stage regenerators. The amount of steam used for stripping was about 0.4% by weight of the catalyst circulation. The pre-lift medium is steam.

Example 1

This embodiment adopts a medium-sized riser reactor, which is a cylindrical structure with a total height of 10 meters and a diameter of 25 centimeters, wherein the height ratio of the lower, middle and upper reaction zones is 0.67:1:7.5. The lowermost part of the riser is the pre-lift section.

The raw material oil processed by the device is that the light raw material introduced from the lower reaction zone is catalytic cracking gasoline; the inferior heavy raw material introduced from the middle reaction zone is vacuum residue; the heavy raw material introduced from the upper reaction zone is wax oil ( vacuum gas oil). The feed amount of the catalytic cracking gasoline is 15% by weight of the gas oil, and the feed amount of the vacuum residue is 20% by weight of the gas oil. The properties of various feedstock oils are listed in Table 1. The brand name of the catalyst is LV-23, which is produced by Qilu Catalyst Factory of China Petrochemical Corporation. The catalyst LV-23 is a cracking catalyst containing Y-type zeolite and ultra-stable Y-type zeolite.

Concrete steps are, as shown in Figure 1, the light raw material after preheating enters lower reaction zone 1 through atomizing nozzle 7, and the waiting catalyst from stripper enters lower reaction zone 1 through catalyst inlet 4, and light raw material and When the raw catalyst is contacted, it rises along the riser reactor and enters the middle reaction zone 2 under the action of the pre-lift medium entering the bottom of the riser reactor through the pipeline 10 .

The preheated vacuum residue enters the middle reaction zone 2 through the atomizing nozzle 8, and the semi-regenerated catalyst from the two-stage regenerator enters the middle reaction zone 2 through the catalyst inlet 5, and the vacuum residue contacts and reacts with the semi-regenerated catalyst; The reactant flow from the lower and middle reaction zones rises along the riser reactor, and the catalyst inlet 6 of the regenerator enters the high-temperature regenerated catalyst in the upper reaction zone through the catalyst inlet 6 of the riser reactor, and enters the pretreatment catalyst in the upper reaction zone 3 through the atomizing nozzle 9 The heated wax oil contacts and mixes, contacts and reacts with the flow in the lower and middle reaction zones and the regenerated catalyst, and the catalyst and reaction materials from the lower to upper reaction zones continue to rise along the riser reactor and reach the exit of the riser reactor Enter settler, separate catalyzer and reaction product, catalyzer obtains the spent catalyst through stripper stripping, obtains semi-regenerated catalyst and regenerated catalyst according to the method of above-mentioned patent CN1221022A, the spent catalyst (carbon content is 0.8-1.2% by weight ), semi-regenerated catalysts (0.16-0.48% by weight of carbon content) and regenerated catalysts (0.01-0.05% by weight of carbon content) are recycled, and the reaction products enter subsequent product separation equipment.

The specific operating conditions are shown in Table 2, and the distribution of products is shown in Table 3. The quality of gasoline products obtained from the cracking reaction is listed in Table 4.

comparative example

This comparative example adopts the medium-sized riser reactor of the continuous reaction regeneration operation identical with the above-mentioned embodiment, and raw material oil is mixed raw material oil, and this mixed raw material oil is made up of wax oil shown in Table 1, vacuum residual oil, vacuum residual oil The amount is 20% by weight of wax oil.

The specific test steps are as follows: the preheated mixed raw oil enters the lower part of the riser reactor through the atomizing nozzle 8, and contacts, mixes and reacts with the high-temperature regenerated catalyst from the regenerator through the pipeline 5, and the catalyst and the reaction material are in the preheating process. Under the action of the lifting medium, it rises along the riser reactor, enters the settler after reaching the outlet of the riser reactor, and separates the catalyst and the reaction product. The catalyst is stripped by the stripper, the regenerator is burnt, and the catalyst is cooled to obtain a regenerated catalyst ( The carbon content is 0.01-0.05% by weight) for recycling, and the reaction product enters subsequent product separation equipment.

The main operating conditions are shown in Table 2, and the distribution of products is shown in Table 3. The quality of gasoline products obtained by catalytic cracking is shown in Table 4.

As can be seen from the data in Table 3, after adopting the oil agent contact mode of the present invention, the yield of dry gas and coke decreased significantly, and the yield of liquid products (liquefied gas+gasoline+diesel) was significantly improved. Comparing the results in Table 4 also shows that by adopting the method provided by the invention, the content of olefins in gasoline products is also significantly reduced, and the content of aromatics and isoparaffins is greatly increased. Therefore, adopting the method provided by the invention can also greatly improve the quality of gasoline products.

Table 1

wax oil   Vacuum residue   FCC gasoline Density(20℃)/g·cm ^-1 0.8916 0.9813 0.7032 Viscosity(100℃)/ ^mm2 ·sec ^-1 6.312 / / Freezing point/℃ 47 / / Acid value/mg KOH·g ^-1 0.81 / / Basic nitrogen/μg·g ^-1 404 762 / Metal (nickel+vanadium)/ppm by weight 0.6+0.8 10.5+3.5 / Carbon residue/weight% 0.36 10.2 / Sulfur content/wt% 0.45 0.87 0.062 Olefin/wt% / / 47.3 Alkanes/wt% 63.6 34.1 23.7 Aromatics/wt% 29.2 38.2 23.4 Colloid/weight% 7.2 21.3 / Asphaltenes/wt% 0.0 6.4 / Distillation range Initial boiling point/℃ 288 398 34 10 volume% distillation point/℃ 365 446 57 30 volume% distillation point/℃ 416 / 70 50 volume% distillation point/℃ 442 / 91 70 volume% distillation point/℃ 466 / 123 90 volume% distillation point/℃ 518 / 159

Table 2

table 3

Product distribution, weight % Example comparative example dry gas 4.13 4.89 Liquefied gas 13.05 12.16 Among them, propylene 6.73 5.88 C5+ gasoline 47.73 48.38 diesel fuel 19.79 18.42 heavy oil 8.25 8.18 coke 7.05 7.97 Liquefied petroleum gas+C5+gasoline+diesel 80.57 78.96

Table 4

Example comparative example Density(20℃)/g·cm ^-1 0.7126 0.7032 Olefin/vol% 42.3 47.3  N-paraffin/volume% 12.6 23.7  Isoparaffins/w/w% 17.9 5.6 Aromatics/volume% 27.2 23.4 Sulfur content/wt% 0.042 0.058 Distillation range   Initial boiling point/°C 33 34  10 volume% distillation point/℃ 56 57   30 volume% distillation point/℃ 70 70  50 volume% distillation point/℃ 90 91  70 volume% distillation point/℃ 122 123  90 volume% distillation point/℃ 160 159

Claims (14)

1. cracking method for hydrocarbon oil, this method is included in the riser reactor that comprises a plurality of reaction zones, under the cracking reaction condition, with hydrocarbon oil crude material and cracking catalyst in each reaction zone contact reacts, catalyzer is separated with reaction product, obtain crackate and reclaimable catalyst, near small part reclaimable catalyst regeneration, obtain half regenerated catalyst and regenerated catalyst, it is characterized in that, described a plurality of reaction zone comprises at least one central reaction zone (2) and at least one top reaction zone (3), and top reaction zone (3) is positioned on the central reaction zone (2); In described central reaction zone (2), introduce poor heavy raw material and half regenerated catalyst, poor heavy raw material is contacted with half regenerated catalyst; At described top reaction zone (3), introduce heavy feed stock and regenerated catalyst, heavy feed stock is contacted with regenerated catalyst; At least one item in the content of the carbon residue content of described poor heavy raw material, metallic nickel and vanadium, asphalt content and the basic n content is higher than described heavy feed stock.

2. method according to claim 1, wherein, the number of described central reaction zone (2) and top reaction zone (3) respectively is one.

3. method according to claim 1 and 2, wherein, described central reaction zone (2) is 1 with the volume ratio of top reaction zone (3): 2-10.

4. method according to claim 1 and 2, wherein, in described central reaction zone (2), described cracking conditions comprise poor heavy raw material and half regenerated catalyst contact temperature be 400-650 ℃, contact pressure be 130-450 kPa, half regenerated catalyst with the agent weight of oil of poor heavy raw material than being 2-15: 1, the weight hourly space velocity of poor heavy raw material is 1-120 hour ^-1, the weight ratio that promotes medium and poor heavy raw material in advance is (0.01-0.1): 1; At described top reaction zone (3), described cracking conditions comprise heavy feed stock and regenerated catalyst contact temperature be 400-650 ℃, contact pressure be 130-450 kPa, heavy feed stock with the agent weight of oil of regenerated catalyst than being 2-15: 1, the weight hourly space velocity of heavy feed stock is 1-120 hour ^-1, the weight ratio that promotes medium and heavy feed stock in advance is (0.01-0.1): 1.

5. method according to claim 4, wherein, in described central reaction zone (2), poor heavy raw material and half regenerated catalyst contact temperature be 450-550 ℃, contact pressure be 200-400 kPa, half regenerated catalyst with the agent weight of oil of poor heavy raw material than being 3-10: 1, the weight hourly space velocity of poor heavy raw material is 2-80 hour ^-1, the weight ratio that promotes medium and poor heavy raw material in advance is (0.03-0.08): 1; At described top reaction zone (3), heavy feed stock and regenerated catalyst contact temperature be 500-600 ℃, contact pressure be 150-250 kPa, heavy feed stock with the agent weight of oil of regenerated catalyst than being 3-10: 1, the weight hourly space velocity of heavy feed stock is 2-60 hour ^-1, the weight ratio that promotes medium and heavy feed stock in advance is (0.03-0.08): 1.

6. according to claim 1,4 or 5 described methods, wherein, one or several in the content of the carbon residue content of described poor heavy raw material, metallic nickel and vanadium, asphalt content or the basic n content meets the following conditions: carbon residue content is more than the 5 weight %, the content of metallic nickel and vanadium is more than 5 ppm by weight, basic n content is more than 800 ppm by weight, and asphalt content is more than the 1 weight %; One or several in the content of the carbon residue content of described heavy feed stock, metallic nickel and vanadium, asphalt content or the basic n content meets the following conditions: carbon residue content is less than 5 weight %, the content of metallic nickel and vanadium is less than 5 ppm by weight, basic n content is less than 800ppm, and asphalt content is less than 1 weight %.

7. method according to claim 6, wherein, described heavy feed stock is selected from one or more in straight-run gas oil, vacuum gas oil, hydrocracking tail oil, hydrofined oil or the solvent-deasphalted oils; Described poor heavy raw material is selected from one or more in wax tailings, long residuum, the vacuum residuum.

8. method according to claim 1 and 2, it is characterized in that, described a plurality of reaction zone also comprises at least one lower reaction zone (1), described lower reaction zone (1) is positioned under the central reaction zone (2), in lower reaction zone (1), introduce lightweight material and reclaimable catalyst or half regenerated catalyst, lightweight material is contacted with reclaimable catalyst or half regenerated catalyst.

9. method according to claim 8, wherein, the number of described lower reaction zone (1) is one.

10. according to Claim 8 or 9 described methods, wherein, described central reaction zone (2) is 1 with the volume ratio of lower reaction zone (1): 0.5-2.

11. method according to claim 8, wherein, in described lower reaction zone (1), described cracking reaction condition be reclaimable catalyst or half regenerated catalyst with lightweight material contact temperature be 300-600 ℃, contact pressure be 200-500 kPa, reclaimable catalyst or half regenerated catalyst with lightweight material agent weight of oil than being 2-15: 1, the weight hourly space velocity of lightweight material is 1-120 hour ^-1, the weight ratio that promotes medium and lightweight material in advance is 0.005-0.1: 1.

12. method according to claim 11, wherein, in described lower reaction zone (1), reclaimable catalyst or half regenerated catalyst and lightweight material contact temperature be 350-500 ℃, contact pressure be 250-400 kPa, reclaimable catalyst or half regenerated catalyst with the agent weight of oil of lightweight material than being 3-10: 1, the weight hourly space velocity of lightweight material is 4-50 hour ^-1, the weight ratio that promotes medium and lightweight material in advance is 0.01-0.05: 1.

13. according to Claim 8,11 or 12 described methods, wherein, described lightweight material is selected from one or more in coker gasoline, straight-run spirit, catalytic gasoline, pressure gasoline or the reforming raffinate oil.

14. method according to claim 1, wherein, described catalyzer is the cracking catalyst that contains zeolite.

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