JPS6337156B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for fluid catalytic cracking of petroleum products that does not substantially contain distillation residues. Fluid catalytic cracking is a process in which petroleum-based hydrocarbons are cracked by contacting them with a catalyst to yield desirable products, mostly gasoline, liquefied petroleum gas, alkylation feedstock, and middle distillate mixtures. Light oil is usually used as the feedstock for fluid catalytic cracking. The term "light oil" here refers to heavy gas oil from atmospheric distillation equipment, distillate oil such as vacuum gas oil from vacuum distillation equipment, and residual oil obtained by removing distillate oil by vacuum or atmospheric distillation. Refers to residual oil from which the asphaltene component has been removed by solvent deasphalting, thermal decomposition, or hydrorefining, or which has been hydrorefined as necessary, and has a boiling point range of 220° to 600°C. It has a specific gravity of about 0.8 to 1.0. In recent years, produced crude oil has tended to become heavier, while demand for hydrocarbon oils with a boiling point fraction below light oil has increased relatively due to environmental issues and ease of use. There is an increasing demand for feedstocks to be processed. In order to cope with the above-mentioned heavier crude oil and increased demand for cracking raw materials, it has become necessary to increase the yield of cracked raw materials, that is, to use more of the heavier fractions as cracking raw materials. Specifically, there is a need for methods to increase the yield of distillate oil in vacuum distillation and to increase the yield of deasphalted oil in solvent deasphalting that removes heavy fractions from distillation residue oil. . On the other hand, it is known that such a heavier cracked feedstock oil is accompanied by an increase in the concentration of metal compounds contained in the feedstock oil. It is desirable not to mix the distillation residue fraction into such a heavy feedstock oil and therefore the feedstock oil supplied to the catalytic cracking unit. It contains components that can be converted into light oil through decomposition, and their use is desirable from the standpoint of effective resource utilization. The residual oil fraction contains high molecular weight resinous materials, asphaltenes, and relatively low molecular weight propane,
It is a mixture of hydrocarbon components that can be extracted with light hydrocarbons such as butane or pentane, and the residual oil fraction is usually treated with the above-mentioned light hydrocarbon solvent to precipitate resinous and asphaltene components.
Methods are being used to extract other components. This kind of purification method is called solvent deasphalting method, and since heavy metal compounds are contained more in the resinous and asphaltene components of the raffinate, the amount of metal compounds in the extract is low, and decomposition is difficult. It becomes possible to use it as a raw material. However, such extracted oil contains more metal compounds than distilled gas oil obtained by distillation, and its range of use is restricted, and the rate of contamination with cracked feedstock oil must be regulated or the residue Regulations such as limiting the yield when extracting from oil are necessary. When these heavy petroleum products are subjected to fluid catalytic cracking, a phenomenon in which iron, nickel, vanadium, and copper contained in the feedstock oil is deposited on the catalyst is particularly noticeable. Normally crude oil contains 1-100ppm iron, 5-500ppm
of nickel, 5-1500ppm vanadium, 0.1-
Contains 10ppm copper. In addition, petroleum feedstocks tend to contain dissolved iron in the equipment upon contact with transport, storage and processing equipment, so the iron content in the feedstock is much greater than the above values. Since these metals tend to remain undistilled during processing, the residual oil contains two to four times or more metals than the raw crude oil. For example, distillation residues can contain as much as 1000 to 2000 ppm vanadium. These metals usually exist as organometallic compounds including polyphyllin ring structures, and when they come into contact with the catalyst at high temperatures, they decompose, and the metals adhere and accumulate on the catalyst. These metals not only reduce the activity of the catalyst but also reduce the selectivity of the catalyst.
In other words, these metals have the ability to hydrogenate and dehydrogenate, and under the reaction conditions of fluid catalytic cracking, they promote the dehydrogenation reaction of hydrocarbons, resulting in the production of undesirable hydrogen gas and coke. The amount increases;
The yield of preferred LPG, gasoline, and kerosene will decrease. As mentioned above, the problem of accumulation of metals on the catalyst that have a detrimental effect on the reaction is not a very important problem in fluid catalytic cracking of gas oil. This is because gas oil has a low metal content, so the amount of metal deposited on the catalyst is generally small, and the amount of catalyst replacement required is also small. In fact, when the amount of metal in the gas oil used as feedstock in gas oil fluid catalytic cracking is low, such as 1 ppm or less, simply replenishing the amount of fresh catalyst equivalent to the amount of catalyst normally lost from the equipment can Negative effects caused by metal accumulation on the catalyst can be avoided. However, in fluid catalytic cracking of heavy oil with high metal content, the amount of metal accumulated in the circulation system is enormous, so special measures are required to maintain catalyst activity and selectivity. . The usual means for this is to periodically or constantly extract a portion of the catalyst and replace it with fresh or regenerated catalyst (e.g., regenerated by ion exchange or redox methods) to maintain activity at a constant level. However, it is necessary to significantly increase the amount of catalyst extracted, which is very disadvantageous in terms of cost. Therefore, the problem of metal deposition on the catalyst becomes a particularly serious problem in fluid catalytic cracking of heavy oil with a high metal content. The inventors of the present invention have conducted extensive research to solve the above problems, and as a result, have completed a new catalytic cracking method using completely new means that can significantly save the amount of make-up catalyst medium. That is, according to the present invention, solvent-deasphalted atmospheric or vacuum distillation residue oils, hydrorefined products thereof, and mixtures of these deasphalted residue oils and vacuum gas oil, etc. (usually,
A method in which catalytic cracking of nickel and vanadium (containing nickel and vanadium of 1 ppm or more) is carried out in the presence of catalyst particles in a fluidized state, in which a part of the catalyst particles are extracted from the catalyst circulation system, and the extracted catalyst particles are , a high-gradient magnetic separation system in which a ferromagnetic filling is placed in a high magnetic field space with a uniform magnetic field strength of 1000 Gauss or more, and has the ability to magnetize minute particles of ferromagnetic or paramagnetic substances on the surface of this filling. Using a dry method, particle concentration is 0.01 to 100 g/sec, fluid linear velocity is 0.01 to 100 m/sec, and wet method is particle concentration 0.01 to 100 m/sec.
The nickel, vanadium, iron, The above-mentioned method is characterized in that the catalyst particles that have become magnetized due to copper deposition are separated into particles that are magnetized and particles that are not magnetized under the treatment conditions, and that the non-magnetized catalyst particles are recycled. provided. The term "magnetized material" as used herein refers to catalyst particles that are collected by magnetic force on the surface of a packing placed in the magnetic field space of a high-gradient magnetic separator. In addition, non-magnetized substances refer to catalyst particles that are not collected on the surface of the packing and are discharged as they are outside the system of the high gradient magnetic separator. The method of the present invention will be explained in more detail below. The present inventors separated the catalyst extracted from the circulation system during fluid catalytic cracking of heavy petroleum into magnetized and non-magnetized substances using a high-gradient magnetic separator, and separated the extracted catalyst into magnetized and non-magnetized substances. When the catalytic activity of the three substances was evaluated using a fixed bed microreactor, the conversion rate was higher in the order of non-magnetized material>extracted catalyst>magnetized material;
It also has excellent selectivity for LPG, gasoline, and kerosene production, and it was found that there is a significant difference in catalytic ability among these three. Furthermore, when the non-magnetized material was returned to the circulation system, it was found that it could be reused without adversely affecting the conversion selectivity, and that the amount of make-up catalyst could be significantly saved. The present invention was completed based on the above-mentioned novel findings discovered by the inventors. That is, in the method of the present invention, nickel, iron, vanadium, and copper contained in heavy petroleum products are deposited on the catalyst, resulting in a decrease in the conversion rate of the reaction, and the reduction of gasoline and kerosene gas oil fractions in the product. The yield of coke and hydrogen decreases, and the yield of coke and hydrogen increases, causing economic losses.
To prevent problems with equipment operation, when a part of the catalyst flowing in the decomposition equipment is extracted and replaced with new or regenerated catalyst, the extracted catalyst is separated from magnetized substances and non-magnetic substances using a high gradient magnetic separator. By separating the magnetized materials and returning the non-magnetized materials, which still maintain high activity and selectivity, to the cracker for reuse, the increase in coke and hydrogen in the product is suppressed, and the conversion rate of the reaction is reduced. This is a method to save the amount of makeup catalyst while preventing. In the present invention, heavy petroleum refers to heavy petroleum containing no substantial amount of distillation residue such as asphaltenes,
These include atmospheric distillation gas oil, vacuum distillation gas oil, solvent-deasphalted oil, residual oil that has been deasphaltenized by heat treatment or hydrorefining treatment, or mixtures thereof, and those obtained by hydrorefining these. In fluid catalytic cracking, the reaction temperature is 480-550
℃, a pressure of 1 to 3 Kg/cm ² G, a catalyst/oil ratio of 1 to 20, and the catalyst is, for example, a silica-alumina catalyst containing about 15 to 20% by weight of alumina or a silica containing about 5 to 50% of zeolite.・Alumina catalyst, etc. The catalyst usually has a thickness of 1 to 1000 μm, preferably 20 to 200 μm.
They are microparticles with a particle size of m. The yield and properties of each product produced by the catalytic cracking method vary depending on the composition of the feed oil, the type of catalyst, and differences in reaction conditions, but as a general range, the yield of the main product, gasoline, is 40 to 60 vol%. , decomposition gas is 15~
25vol%, cracked light oil 20~40vol%, coke 3~
It is 8wt%. In the fluid catalytic cracking referred to here, the hydrocarbon raw material described above is brought into continuous contact with the catalyst kept in a fluidized state under the temperature and pressure conditions described above. This contact may be carried out in the bed of the catalyst, or by so-called riser cracking, in which the catalyst particles and the raw material rise together in a tube. The mixture of reactants, unreacted raw materials, and catalyst thus catalyzed is generally fed into a stripping zone and
Most of the hydrocarbons such as products and unreacted products are removed. The catalyst loaded with carbonaceous and some heavy hydrocarbons is continuously removed from the stripping zone and sent to the regeneration zone. In the regeneration zone (regeneration tower), the carbonaceous catalyst is subjected to oxidation treatment. In this regeneration zone as well, the catalyst is maintained in a fluidized state and is subjected to combustion treatment at a temperature of 560 to 650°C using normal air. The catalyst that has undergone this oxidation treatment is a regenerated catalyst, in which carbonaceous substances and hydrocarbons deposited on the catalyst have been reduced. This regenerated catalyst is continuously recycled to the reaction zone. In the fluidized catalytic cracking of heavy petroleum products containing distillation residues of the present invention, a part of the fluidized catalyst circulating between the reaction tower and the regeneration tower is removed from the stripper outlet, the regeneration tower exit, or other equipment that may interfere with the operation of the equipment. Pull it out from a suitable place. In this case, it may be extracted continuously or discontinuously at regular intervals as long as it does not adversely affect the product. The removed catalyst may be treated as is or before being subjected to a high gradient magnetic separator. The high gradient magnetic separator is a ferromagnetic packing placed in a homogeneous high magnetic field space, and a ferromagnetic packing is placed around the packing.
By generating a magnetic field gradient as high as ×10 ³ to 20,000 × 10 ³ Gauss/cm, ferromagnetic or paramagnetic microparticles are magnetized on the surface of the filling, and the weak paramagnetism of non-magnetized objects is It is a magnetic separator designed to be able to separate microparticles or diamagnetic microparticles. As the above-mentioned ferromagnetic filler, an aggregate of fine ferromagnetic wires such as steel wool or steel net having a diameter of 1 to 1000 .mu.m is usually used. An example of a high gradient magnetic separator is the high gradient magnetic separator produced and sold by SALA of Sweden. On the other hand, drum-type magnetic separators, which have traditionally been used to separate relatively large ferromagnetic particles in magnetic beneficiation of iron ore, have a magnetic field strength of approximately 500 Gauss and a magnetic field gradient of approximately 500 Gauss/cm. Therefore, the magnetic field strength and magnetic field gradient of the high-gradient magnetic separator referred to in the present invention are significantly smaller than that of the high-gradient magnetic separator. Although it can remove powder, it cannot be used to separate catalysts containing deposited metals used in fluid catalytic cracking of heavy petroleum products. Methods for processing solid particles using high gradient magnetic separators include dry methods using air, nitrogen, steam, and mixtures thereof as carrier fluids, and wet methods using water or other liquids as carrier fluids. In the present invention, either a dry method or a wet method may be used. Process variables when operating a high gradient magnetic separator typically include magnetic field strength, magnetic field gradient, linear velocity, particle concentration, processing temperature, catalyst particle size, type, state and amount of deposited metal, and desired separation level. , the optimum values of process variables vary greatly depending on the selectivity of separation. Magnetic field strength is the strength of the magnetic field in the space where the filling is placed, and is usually 1000 ~ for both dry and wet methods.
20,000 Gauss or more is used. The magnetic field gradient is the amount of change in the strength of the magnetic field that occurs around the filling, and can be changed by changing the magnetic field strength or by changing the type and diameter of the filling.
In both wet methods, 2000×10 ³ to 20000×10 ³ Gauss/cm is usually used. Particle concentration refers to the concentration of catalyst particles that are subject to magnetic separation in a carrier fluid consisting of gas or liquid, and in dry methods it is usually between 0.01 and 100.
It is operated at a particle concentration of g/g/g. Wet processes are usually operated at particle concentrations of 0.01 to 1000 g/g/. Processing temperature refers to the temperature of the catalyst particles that are subject to magnetic separation, and more precisely, it refers to the temperature of iron, nickel, vanadium, and copper deposited on the catalyst particles. The treatment temperature is preferably below the Curie temperature of these metals, and usually room temperature is used. In addition, by changing the linear velocity of the fluid as it passes through the magnetic field, it is possible to greatly change the separation level and separation selectivity.When high selectivity is required, the linear velocity can be increased. drive. In the dry method, a linear velocity of 0.01 to 100 m/sec is usually used. Usually 0.01 to 10000 in wet method
A linear velocity of m/hr is used. The high gradient magnetic separator may be integrated into the fluid catalytic cracker line or may be operated in batches without integration. The extracted catalyst is separated by a high-gradient magnetic separator into magnetized catalyst particles, which have large amounts of iron, nickel, vanadium, and copper deposited, and non-magnetized catalyst particles, which do not have large amounts of these metals deposited. Although it is divided into magnetic materials, the weight ratio of magnetized materials to non-magnetized materials is usually 1:100 to 100:1, and may range from 1:1000 to 1000:1 in some cases. Preferably, the separation is within a range of 1:10 to 10:1. The amount of metal deposited on magnetized catalyst particles depends on the type of catalyst used in the fluid catalytic cracking reaction, the intended product,
Although it varies greatly depending on the reaction conditions, etc., it is usually in the range of 0.05 to 20 wt%, preferably 0.1 to 5 wt% in terms of nickel equivalent. Note that the nickel equivalent referred to here is a value expressed by the following formula. Nickel equivalent = [Ni] + 0.25 x [V] + 0.1 x [Fe]
+0.1×[Cu] ([Ni], [V], [Fe], and [Cu] represent the concentration of nickel, vanadium, iron, and copper, respectively. The amount of metal deposited in the non-magnetized material after separation is compared Since it still has high activity and selectivity, it is returned to the circulation system for reuse.In this case, make up a new or regenerated catalyst equal to the separated and removed magnetized material to reduce the amount of catalyst in the circulation system. It is usually done to prevent the fluid balance from being disrupted and the catalyst activity to decrease by keeping the same amount as before extraction.The catalyst is introduced into the circulation system at the regeneration tower inlet, regeneration tower exit transfer line, or other heat source. A location is selected that will not affect the balance or flow balance.Next, the magnetized material after magnetic separation can be discarded or
The deposited metal may be reused after being removed from the catalyst by methods such as ion exchange, chlorination, sulfidation, CO conversion, oxidation, and reduction. In the case of regeneration, the regenerator may be connected to the high gradient magnetic separator and integrated into the line, or it may be separated and operated in batches. Example 1 Using a silica-alumina fluid catalytic cracking catalyst containing approximately 5 wt% of zeolite, a part of the circulating catalyst was replaced with a new catalyst using a fluid catalytic cracking pilot device, and the solvent from the vacuum residue was removed from the deasphalted oil and distilled under reduced pressure. Catalytic cracking was carried out using the mixed oil with gas oil as the raw material. The extracted catalyst is treated with a high-gradient magnetic separator, separated into equal amounts of magnetized and non-magnetized materials, and subjected to metal analysis and fixed bed analysis for the extracted catalyst, magnetized materials, and non-magnetized materials. Activity evaluation was performed using a microreactor. These results are shown in Table 1. The non-magnetized material has values close to those of the new catalyst in terms of conversion rate, carbon production rate (CPF), and hydrogen generation amount (H ₂ /CH ₄ vol ratio), and has sufficient activity and selectivity to withstand reuse. You can see that it is retained.

[Table] Example 2 Using a silica-alumina fluid catalytic cracking catalyst containing approximately 5 wt% of zeolite, catalytic cracking of solvent-deasphalted oil was performed using a fluid catalytic cracking pilot device while replacing a part of the circulating catalyst with a new catalyst. It was carried out under low conversion operating conditions. In this case, to obtain the products shown in the left column of Table 2, the treated oil 1
Required 1.1 pounds of new catalyst per barrel. Next, a high-gradient magnetic separator is installed in the fluid catalytic cracking pilot equipment, and the extracted catalyst is separated into magnetized and non-magnetized materials by the high-gradient magnetic separator, and the non-magnetized materials are returned to the circulation system for reuse. did. In this case, 0.6 pounds of new catalyst was required per barrel of treated oil to obtain approximately the same product as without the high gradient magnetic separator. Therefore, it can be seen that the amount of make-up catalyst can be greatly reduced by using a high gradient magnetic separator. Note that the pentane extract remaining from Kuwait vacuum was used as the raw material oil. The raw material oil properties are as follows. Specific gravity 0.986 Sulfur content (wt%) 4.70 Residual carbon (wt%) 8.9 Nickel (wt ppm) 12 Vanadium (wt ppm) 28

[Table] Example 3 A fluidized catalytic cracking pilot unit containing 2 kg of silica-alumina type catalytic cracking catalyst was charged with vacuum gas oil obtained from Middle Eastern crude oil 26 days a day, and vacuum residual oil obtained from Middle Eastern crude oil was deasphalted with solvent. 10% of the deasphalted oil obtained by
A catalytic cracking experiment was conducted under normal high conversion operating conditions by supplying 36 times a day of mixed feedstock oil at a rate of 1/day. Note that the above raw material oils were all subjected to hydrodesulfurization treatment before use. The experimental conditions for catalytic cracking were that the reaction temperature was 492°C, the reaction pressure was normal pressure, and the feedstock oil was charged into a fluidized bed cracking reactor at a rate of 1.5 hours per hour and separated, and the cracked products flowing out from the reactor were separated. was cooled and liquefied. The catalyst is continuously extracted from the reactor at a rate of 10 kg per hour, charged into a regenerator to remove carbonaceous substances attached to the catalyst particles, oxidized with air and regenerated, and then continuously returned to the reactor. It was charged and used repeatedly. The properties of the raw material oil used in the experiment were as shown in Table 3.

[Table] After extracting a portion of the catalyst circulating in the equipment from the regenerator at a rate of approximately 150g once a day, 170g
The experiment was conducted continuously for 21 days while replenishing the regenerator with new catalyst. In addition to the catalyst extracted at a rate of 150g per day, a small amount of catalyst was lost from the reactor and regenerator together with decomposition products and regenerator waste gas, but the amount of catalyst retained after 21 days was 2.1Kg. It was confirmed that the replenishment amount and the withdrawal amount were almost in equilibrium. Analysis of the catalyst in the device after 21 days revealed that it contained 252 ppm of nickel, 608 ppm of vanadium,
and contained 120 ppm iron. As a result, if you keep the amount of catalyst in the equipment at 2 kg while replenishing approximately 170 g of new catalyst per day, the degree of catalyst contamination by metals can be reduced to approximately 2 kg.
It turned out that it could be kept at 980ppm. The above experiment was repeated for another 15 days under the same conditions. However, the amount of catalyst was withdrawn four times a day, and 500 g was withdrawn each time, separated by a high-gradient magnetic separator, and about 480 g each time was recovered as non-magnetized material and charged into the apparatus again. Additionally, 100g of new catalyst was supplied to the regenerator once a day. When the catalyst in the device was analyzed for metals after 15 days, it was found to be 232ppm of nickel and 620ppm of vanadium.
It was found that the soil was contaminated with 904 ppm of metals, including 52 ppm of iron and 52 ppm of iron. From the above results, it was confirmed that when the method of the present invention is applied, the weight can be reduced from 170 g when not applied to 100 g. The operating conditions of the high gradient magnetic separator and the analysis results of the catalyst separated as a magnetized substance during operation were as shown in Tables 4 and 5. The product distribution is as shown in Table 6, and almost the same products were obtained with and without catalyst recovery using a high gradient magnetic separator.

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Claims (1)

[Scope of Claims] 1. A method for catalytically cracking solvent-deasphalted normal pressure or vacuum distillation residue oils or deasphalted residue oils containing hydrorefined products thereof in the presence of catalyst particles in a fluidized state. , Some of the catalyst particles are extracted from the catalyst circulation system,
The extracted catalyst particles are placed in a ferromagnetic packing in a high magnetic field space with a uniform magnetic field strength of 1000 Gauss or more, and the packing has the ability to magnetize minute particles of ferromagnetic or paramagnetic material on the surface of the packing. Using a certain high gradient magnetic separator, the particle concentration is 0.01 ~ 0.01 in the dry method.
100g/, fluid linear velocity 0.01-100m/sec, wet type particle concentration 0.01-1000g/, fluid linear velocity 0.01
The nickel, vanadium, iron, and
A deasphalting residue characterized in that the catalyst particles that have become magnetized due to copper deposition are separated into particles that are magnetized and particles that are not magnetized under the treatment conditions, and that the non-magnetized catalyst particles are recycled. Fluid catalytic cracking method for oils.