JPS6337835B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a fluid catalytic cracking method for heavy petroleum products. 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, distilled oil such as vacuum gas oil from vacuum distillation equipment, or hydrogenated products of these as necessary, and has a boiling point range of 220° to 600°C. ,specific gravity
It is about 0.8 to 1.0. However, while the crude oil produced has tended to become heavier in recent years, demand for hydrocarbon oils with a boiling point fraction lower than diesel oil has increased relatively due to environmental issues and ease of use. Using it as a raw material for decomposition has caused problems in terms of raw material resources. Also, from the perspective of energy conservation, the effective use of heavy petroleum products has become an important issue. Under such circumstances, attempts are being made to use heavy petroleum as a raw material for fluid catalytic cracking as one of the heavy oil treatment processes. When fluid catalytic cracking of heavy petroleum is carried out, the phenomenon in which nickel, vanadium, iron, and copper contained in the feedstock oil is deposited on the catalyst is particularly noticeable. Normally crude oil contains 5 to 500 ppm of nickel, 5 to 500 ppm of nickel,
1500ppm vanadium, 1~100ppm iron, 0.1~
Contains 10ppm copper. In addition, petroleum feedstocks tend to contain dissolved iron in equipment due to contact with transportation, storage, and processing equipment, so the iron content in the feedstock greatly exceeds 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 residue oils 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, in fluid catalytic cracking of light oil,
The negative effects caused by metal build-up on the catalyst can be avoided by simply replenishing an amount of fresh catalyst that corresponds to the amount of catalyst that would inevitably spill out of the device. However, in fluid catalytic cracking of heavy oil or residual oil with a high metal content, the amount of metal accumulated in the circulation system is enormous, so special measures are required to maintain the activity and selectivity of the catalyst. It becomes necessary. 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 extremely 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 or residual oil with a high metal content. As a means to solve this problem, a method of suppressing the activity of metal deposited on the catalyst is known. Specifically, in order to passivate the deposited metal and eliminate its activity, there are a method in which a passivating agent is included in the catalyst in advance, and a method in which a passivating agent is added into the fluid catalytic cracking system. This type of method has already been used in JP-A Nos. 52-68092, 53-26801, and 53-
104588 and 53-142406, and it has been confirmed that it is an effective method. However, although this type of method extends the life of the catalyst, some part of the catalyst must be periodically replaced with fresh or regenerated catalyst to maintain a constant level of catalyst activity. Must not be. During this exchange, the catalyst containing the catalyst that is still highly active is extracted, so this problem still remains and is not an essential solution. The present inventors conducted intensive research to solve the above problems, and as a result, devised a completely new means and completed a new catalytic cracking method. That is, according to the present invention, in a method for fluid catalytic cracking of heavy petroleum, a cracking catalyst with a particle size of 5 to 200 μm is used, and a fluid catalytic cracking apparatus comprising a reaction zone, a separation zone, a stripping zone, and a catalyst regeneration zone is A part of the flowing catalyst particles is extracted, and the extracted catalyst particles are transferred to a particle concentration of 0.01 to 500 g/sec and a transfer fluid velocity of 0.01 to 100 m/sec by a transfer fluid selected from the group consisting of air, steam, nitrogen, or a mixture thereof. In this case, a wire made of ferromagnetic material with a diameter of 10 to 1000 μm is placed in a uniform high magnetic field space.
The extracted catalyst particles are sent to a high-gradient magnetic separator equipped with one or more 80-mesh mesh packing stacked one on top of the other, thereby separating the extracted catalyst particles from nickel, vanadium, iron, and copper contained in the heavy petroleum. It is characterized by separating into magnetized catalyst particles and non-magnetized particles, which have become magnetized particles by depositing at least one kind of metal selected from the group, and returning the non-magnetized catalyst particles to the decomposition device for reuse. A method for fluid catalytic cracking of heavy petroleum is provided. Hereinafter, magnetized catalyst particles will be simply referred to as magnetized materials, and non-magnetized catalyst particles will be referred to as non-magnetized materials. 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 in fluid catalytic cracking of heavy petroleum into magnetized and non-magnetized substances using a high gradient magnetic separator, and separated the extracted catalyst, magnetized and non-magnetized substances. When the catalytic activity of the three types 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 has been completed based on the above-mentioned novel findings discovered by the present inventors. That is, the method of the present invention can be applied to nickel, vanadium, etc. contained in heavy petroleum. The deposition of iron and copper on the catalyst lowers the conversion rate of the reaction, lowering the yield of gasoline and kerosene and gas oil fractions in the product, and increasing the yield of coke and hydrogen, causing economic losses. ,
In order to prevent problems in the operation of the equipment, a part of the catalyst flowing in the separator is extracted and when it is mixed 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. The heavy petroleum products referred to in the present invention are heavy petroleum products containing a substantial amount of distillation residue components such as asphaltenes, such as atmospheric distillation residue oil of crude oil, vacuum distillation residue oil, and those obtained by hydrodesulfurization of these. Alternatively, it does not contain a substantial amount of distillation residue such as asphaltenes, and is an atmospheric distillate oil, a vacuum distillate oil, a solvent deasphalted oil, a residual oil that has been treated to remove asphaltene by heat treatment or hydrorefining treatment, or a mixture thereof. These are hydrorefined. In the fluid catalytic cracking of the present invention, normal operation is carried out, that is, reaction temperature is 480 to 550°C, pressure is 1 to 3 kg/
cm ² G, catalyst/oil ratio 1-20, contact time 1-10 seconds. The catalyst may be a catalyst commonly used for catalytic cracking of petroleum, such as a silica-alumina catalyst containing about 15 to 20% by weight of alumina or a silica-alumina catalyst containing about 5 to 50% of zeolite.
The catalyst usually has a thickness of 5 to 200 μm, preferably 20 to 150 μm.
It belongs to 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 the reaction conditions, but within this 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 fluid catalytic cracking of heavy petroleum products of the present invention,
A portion of the fluidized catalyst circulating between the reaction tower and the regeneration tower is extracted from the stripper outlet, the regeneration tower exit, or any other suitable location that does not interfere with the operation of the apparatus. 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. An example of a high gradient magnetic separator is the high gradient magnetic separator produced and sold by SALA. The net-like filling made of a ferromagnetic substance can be made of any material as long as it is made of a ferromagnetic substance, such as expanded metal made of stainless steel. The wire diameter of the net of the net-like packing is usually 10 to 1000 μm.
The thickness is preferably 50 to 700 μm. The mesh size of the reticulated packing usually needs to be in the range of 3 to 80 meshes, preferably 5 to 50 meshes, in order for the catalyst particles to pass through the packing and be processed.
If the mesh size is smaller than 80 meshes, non-magnetized substances will be mechanically retained, and if the mesh size is larger than 3 meshes, more particles will pass through the filling without being efficiently magnetized. One or more sheets of the net-like filling are laminated, but in some cases, a spacer or the like is inserted between the net-like fillings,
Sometimes there is a certain interval. Magnetic separation is performed by passing the catalyst along with a transport fluid through a magnetic field space. The transfer fluid is selected to have no adverse effect on the catalyst, and air, steam, nitrogen, and mixtures thereof are used from the viewpoint of economy and safety. Process variables when operating a magnetic separator typically include magnetic field strength, magnetic field gradient, particle concentration, transport fluid linear velocity, and processing temperature, as well as catalyst particle size, type, state, and amount of deposited metal, and desired separation. level,
Depending on the selectivity of the separation, the optimal values of process variables vary widely. The magnetic field strength refers to the strength of the magnetic field in the space in which the filling is placed, and is usually 1000 Gauss or more, preferably 2000 Gauss or more. The magnetic field gradient is the amount of change in the strength of the magnetic field generated around the filling depending on the distance, and is closely related to the wire diameter of the net-like packing, but generally the smaller the wire diameter, the larger the magnetic field gradient. Usually 2000×10 ³ ~20000×10 ³
Gauss/cm. Particle concentration refers to the concentration of catalyst particles in the transfer fluid. Usually 0.01-500g/preferably 0.1-100
g/. Furthermore, by changing the linear velocity of the transferred fluid as it passes through the magnetic field space, the separation level and separation selectivity can be greatly changed.
Usually 0.01~100m/sec Preferably 0.1~50m/sec
It is. If the linear velocity is less than 0.01m/sec,
Non-magnetized substances are also mechanically trapped, and if the speed is over 100 m/sec, most of the magnetized substances will pass through, making both the separation level and separation selectivity unsuitable for practical use. The processing temperature refers to the temperature of the catalyst particles that are the subject of magnetic separation, and more precisely, it refers to the temperature of nickel, vanadium, iron, 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. 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 into nickel, vanadium,
The weight of magnetized and non-magnetized materials is divided into magnetized materials, which are catalyst particles with large amounts of iron and copper deposited, and non-magnetized materials, which are catalyst particles with no large amount of these metals deposited. The ratio can range from 1:1000 to 1000:1. Preferably, the separation is within a range of 1:100 to 100:1. The amount of metal deposited on magnetized catalyst particles varies greatly depending on the type of catalyst used in the fluid catalytic cracking reaction, the reaction conditions of the target product, etc., but it is usually 0.05 to 0.05 in terms of nickel equivalent.
20wt% preferably in the range of 0.1-5wt%. Note that the nickel equivalent referred to here is a value expressed by the following formula. Nickel equivalent = [Ni] + 0.25 × [V] + 0.1 × [Fe] + 0.1 × [Cu] ([Ni], [V], [Fe], and [Cu] are respectively nickel,
Represents the concentration of vanadium, iron, and copper. ) The unmagnetized material after separation has a relatively small amount of metal deposited and still has high activity and selectivity, so it is returned to the circulation system and reused. In this case, make up the same amount of new or regenerated catalyst as the separated and removed magnetized material to keep the amount of catalyst in the circulation system the same as before extraction to prevent the flow balance from being disrupted and the catalyst activity from decreasing. is usually done. The location where the catalyst is introduced into the circulation system is selected from the regeneration tower inlet, the regeneration tower exit transfer line, or other locations where the heat balance and flow balance are unlikely to be affected. Next, the magnetized material after magnetic separation can be discarded,
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 about 5 wt% zeolite, atmospheric distillation residue oil was catalytically cracked using a fluid catalytic cracking pilot device while replacing a part of the circulating catalyst with a new catalyst. . Further, the extracted catalyst was treated in a high gradient magnetic separator under conditions such that almost equal amounts of magnetized materials and non-magnetized materials could be separated. Expanded metal made of stainless steel was used as the filler, and air was used as the transfer fluid. Furthermore, the amounts of nickel and vanadium were analyzed for the extracted catalyst, magnetized material, and non-magnetized material, and the activity was evaluated using a fixed bed microreactor. The above results are shown in Table-1.

[Table] It can be seen that similar separations can be achieved under different conditions depending on the combination of conditions. 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, indicating that it maintains sufficient activity and selectivity to withstand reuse. Note that Gatsuchi Saran atmospheric residual oil was used as the raw material oil. The raw material oil properties are as follows. Specific gravity 0.967 Sulfur content (wt%) 2.68 Residual carbon (wt%) 10.93 Nickel (wt ppm) 45 Vanadium (wt ppm) 225 Example 2 Using a silica-alumina fluid catalytic cracking catalyst containing about 5 wt% zeolite, Catalytic cracking of the residual oil was carried out using a fluid catalytic cracking pilot unit while replacing part of the circulating catalyst with new catalyst. In this case, 1.5 pounds of new catalyst was required per barrel of treated oil to obtain the products shown in the left column of Table 2. Next, a high gradient magnetic separator was installed in the fluid catalytic cracking pilot equipment, and the extracted catalyst was separated into magnetized materials and non-magnetized materials by the high gradient magnetic separator under the same conditions as Example 1 of Example 1. The material was returned to the circulatory system for reuse. In this case, the treated oil 1
Required 0.8 pounds of new catalyst per barrel. 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 Gatsuchisaran atmospheric residual oil (same as in Example 1) was used as the raw material oil.

[Table] Example 3 The catalyst extracted in Example 1 was treated in a high gradient magnetic separator under several conditions. The magnetized material thus obtained was analyzed for nickel and vanadium content and its activity was evaluated. Note that expanded metal made of stainless steel with a wire diameter of 700 μm and 10 meshes was used as the filler, and air was used as the transfer fluid. The results are shown in Table-3.

[Table] The term "magnetized material ratio" as used herein refers to the ratio of magnetized material to the amount of catalyst treated. Catalysts with different metal contents can be separated by changing the conditions.

Claims (1)

[Scope of Claims] 1. In a method for fluid catalytic cracking of heavy petroleum, a cracking catalyst with a particle size of 5 to 200 μm is used, and a fluid catalytic cracking apparatus comprising a reaction zone, a separation zone, a stripping zone, and a catalyst regeneration zone is A part of the flowing catalyst particles is extracted, and the extracted catalyst particles are exposed to air,
Particle concentrations from 0.01 to
500g/and transfer fluid velocity 0.01~100m/sec
The diameter of the wire made of ferromagnetic material in a uniform high magnetic field space is
The nickel, vanadium, iron and copper contained in the heavy petroleum are separated from the heavy petroleum by sending it to a high gradient magnetic separator equipped with one or more stacked mesh packings of 3 to 80 meshes with a diameter of 10 to 1000 μm. The extracted catalyst particles are magnetized by the deposition of at least one metal of the group consisting of: Nickel equivalent = [Ni] + 0.25 x [V] + 0.1 x [Fe] + 0.1 x [Cu] ( In the formula, [Ni], [V], [Fe] and [Cu] are
Concentrations in weight percent of nickel, vanadium, iron and copper, respectively, deposited on catalyst particles. ) Separate into a magnetized part with a nickel equivalent value of 0.1 to 5% by weight and a non-magnetized part with a lower nickel equivalent value than the magnetized part, and return the non-magnetized part to the decomposition device for reuse. A method for fluid catalytic cracking of heavy petroleum products, which is characterized by: