A method and apparatus for evaluating fixed fluidized bed catalysts for cracking of crude oil to olefins

Abstract

The application discloses a fixed fluidized bed catalyst evaluation method and device for cracking crude oil to obtain olefins, and the device comprises a fixed fluidized bed reactor which is composed of a settling section, a reaction section and a dispersion section from top to bottom; a flange is arranged at the top of the fixed fluidized bed reactor, and an additive pipe, a thermocouple sleeve and a reaction oil gas outlet pipe arranged on the flange are in communication with the inside of the fixed fluidized bed reactor; the settling section is in the shape of a circular truncated cone with a small top and a large bottom; the reaction section is in the shape of an inverted circular truncated cone with a large top and a small bottom; a reinforced distribution ring is arranged in the center of the reaction section; a crude oil inlet is vertically inserted into the bottom of the fixed fluidized bed reactor and is located at the center of the bottom of the fixed fluidized bed reactor; and the outlet is arranged at the bottom of the fixed fluidized bed reactor. The method and device have good repeatability of test data, accurate temperature control, a wide adjustment operation range and the ability to adapt to the evaluation test of catalytic cracking reaction performance under high-temperature conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to a fixed fluidized bed reactor evaluation method and device for evaluating catalyst performance for catalytic cracking of crude oil to produce olefins and analyzing properties of crude oil in the field of petroleum processing. BACKGROUND

[0002] In the current situation of overcapacity of oil refining and insufficient processing capacity of oil refining units, it is undoubtedly of broad and attractive application prospect to fully utilize existing catalytic units to realize the transformation of oil refining to chemical industry.

[0003] Two new processes developed by ExxonMobil and Saudi Aramco for directly converting crude oil into light olefins are reported to save up to $100-200 per ton of ethylene produced by a refinery, indicating that crude oil as a raw material has obvious cost advantage. At the same time, in recent years, the technology for producing low-carbon olefins by catalytic cracking has developed rapidly, and it has been found from the comparison of the properties of raw materials that it is completely feasible to produce low-carbon olefins by catalytic conversion of crude oil.

[0004] Therefore, it is necessary to study the standard evaluation equipment and instruments for direct production of low-carbon olefins by high-temperature cracking of crude oil, and to establish an evaluation equipment that can reflect the activity of catalysts and heavy oil, so as to improve the evaluation efficiency and accuracy of catalysts and provide technical support for subsequent process development.

[0005] Fixed fluidized bed is an important evaluation test device in catalytic laboratory, and its good operation flexibility is widely used in catalytic cracking test.

[0006] USP 6,069,012 discloses an improved fixed fluidized bed reactor, the structure of which is shown in Figure 1 The structural improvement of the reactor mainly lies in the following two aspects: (1) a feed sleeve with adjustable nozzle height is adopted, the inner tube of the sleeve is used to transport raw oil, and the sleeve is used to transport fluidizing gas; (2) a fluidizing gas nozzle is additionally arranged at the bottom of the reactor. The above-mentioned structural improvement enables the fixed fluidized bed to adjust the reaction time by adjusting the height of the feed nozzle. In addition, the additional fluidizing gas nozzle at the bottom of the reactor can improve the fluidization form of the catalyst, but when the linear velocity of the reactor bed layer is large, the catalyst bed layer will have severe turbulent flow and surging, and the catalyst will be lifted to the top of the reactor, deviating from the constant temperature section of the reactor, so that the reaction temperature cannot be effectively controlled. Due to the above-mentioned bed speed limitation, the reactor is only suitable for evaluating catalysts and properties of crude oil under conventional conditions, and is not suitable for evaluating the reaction performance of heavy oil cracking to produce low-carbon olefins at high temperature.

[0007] CN2512495 discloses a fixed fluidized bed reactor for catalytic cracking test research, as shown inFigure 2 As shown, the reactor is divided into a settling section, a reaction section, and an initial contact section between the catalyst and the reactant, from top to bottom. The fixed fluidized bed reactor incorporates a fluidizing medium distribution plate and a perforated plate. These improvements further enhance the fluidization state of the catalyst. Simultaneously, the top-down feedstock method improves the control over the preheating temperature of the feedstock, thus enhancing its adaptability to heavy oil catalytic cracking and harsh reaction conditions. However, because the upper part of the reactor still uses a relatively large cylindrical settling section, the reaction oil and gas may remain in this section for too long during the experiment, leading to over-cracking and the generation of a large amount of dry gas. This results in poor consistency between the results and industrial data, affecting the accuracy of the evaluation experiment.

[0008] CN200720169455.1 discloses a fixed fluidized bed reactor for experimental research, such as... Figure 3 As shown, the reactor is divided into three parts from top to bottom: a settling section, a reaction section, and an initial contact section between the oil and the catalyst. This fixed fluidized bed has a frustum-shaped design. In systems producing large amounts of small-molecule olefins, the reaction products have a faster linear velocity in the high-temperature upper part of the reactor, shortening the coexistence time of intermediate products in the dilute phase of the catalyst and improving the suppression of condensation reactions between small-molecule olefins. However, the settling section of this reactor is prone to over-cracking, resulting in higher yields of dry gas and coke. Furthermore, the feedstock enters from the bottom, and during direct upward injection, it is prone to jetting and channeling phenomena upon contact with the catalyst, especially at high temperatures, directly affecting the repeatability and accuracy of the evaluation data.

[0009] CN200720090308.5 discloses a fixed fluidized bed reactor with a shell. Inside the shell, the upper part is a cylindrical settling section, and the lower part is an inverted conical reaction section. The feed oil and steam inlet pipe consists of an inlet pipe and an outer sleeve surrounding the outer wall of the inlet pipe. An annular steam inlet channel is formed between the inlet pipe and the outer sleeve. Atomizing nozzles are provided at the bottom of the inlet pipe and the outer sleeve, and a steam inlet pipe is provided at the top of the outer sleeve. At least two layers of grid plates are arranged axially within the reaction section. The feed oil and fluidizing gas enter from the top, are preheated at high temperature, and then contact the catalyst. The reacted oil and gas enter the oil-gas separation system through a filter at the top. The top settling area of ​​this reactor is prone to forming dead zones, affecting the accuracy of its analysis and evaluation.

[0010] CN201611229577.5 discloses a fixed fluidized bed reactor, the feed system of which enters the reactor along the center of the top end of the reactor, and the feed system comprises an inner fluidization pipe, a raw material pipe, an outer fluidization pipe, a flow divider, and an injection port of the inner fluidization pipe. The inner fluidization pipe, the raw material pipe, and the outer fluidization pipe are cylindrical, and the upper ends of the three pipes are coaxially connected but not communicated with each other. From the outside to the inside, the three pipes are the outer fluidization pipe, the raw material pipe, and the inner fluidization pipe in sequence, and the lengths of the three pipes increase in sequence. The feed system can better control the temperature of the raw material in the feed pipe, effectively control the reaction temperature, and reduce the coking of the raw material in the raw material pipe.

[0011] CN 102565209A discloses a method for evaluating the performance of a catalyst for catalytic cracking of heavy oil to produce low-carbon olefins, which comprises the following steps: A. loading microspherical catalyst into a fixed fluidized bed reactor; B. mixing the vaporized heavy oil with high-temperature steam in a preheater and then passing the mixture through the catalyst bed; C. separating the oil gas after reaction in a gas-liquid separator, purifying the gas, and then analyzing the gas by an online chromatograph, and analyzing the composition of the liquid by chromatography after the liquid is allowed to stand and is sealed in a bottle; and D. regenerating the catalyst by using oxygen after reaction and calculating the coke content. The test method is only suitable for catalytic cracking of heavy oil, the reactor cannot be used for evaluation of crude oil + backfiring products, and the flow field distribution of the catalyst in the reactor is different from that of the present application, so that the effect of producing low-carbon olefins is poor.

[0012] In summary, the fixed fluidized bed reactors and evaluation methods for experimental research on catalytic cracking of heavy oil to produce low-carbon olefins have various defects. SUMMARY

[0013] The present application aims to solve the defects of the fixed fluidized bed reactors for experimental research on catalytic cracking of heavy oil to produce low-carbon olefins, and provides an evaluation method for a high-temperature fixed fluidized bed reactor for cracking of crude oil to produce olefins.

[0014] To achieve the above-mentioned purpose, the present application provides a fixed fluidized bed catalyst evaluation device for cracking of crude oil to produce olefins, which comprises:

[0015] The fixed fluidized bed reactor is composed of a settling section, a reaction section and a dispersion section from top to bottom; the top of the fixed fluidized bed reactor is provided with a flange, and the additive pipe, thermocouple sleeve and reaction oil gas outlet pipe arranged on the flange are in communication with the inside of the fixed fluidized bed reactor; the settling section is in the shape of a circular truncated cone with a smaller upper end and a larger lower end, the angle between the circular truncated cone and the horizontal direction is 30-60 degrees, and the ratio of the diameter to the diameter of the upper end is 1-3:1; the ratio of the height of the circular truncated cone to the diameter of the upper end is 1-10:1; the reaction section is in the shape of an inverted circular cone with a larger upper end and a smaller lower end, the ratio of the height of the reaction section to the diameter of the upper end is 1-10:1; the central part of the reaction section is provided with a reinforced distribution ring, and a gap is left between the reaction section and the wall of the fixed fluidized bed reactor, and the distance of the gap is 10-30% of the maximum diameter of the dispersion section; the crude oil inlet is vertically inserted into the bottom of the fixed fluidized bed reactor and is located at the center of the bottom of the fixed fluidized bed reactor, and a nozzle is arranged at the outlet; the fluidization auxiliary gas inlet is in the form of a sleeve, and the auxiliary gas passes through the outer layer of the crude oil inlet pipe; the dispersion section is also provided with a surrounding relationship between the backfired oil inlet, the nitrogen gas pipeline and the backfired oil pipeline, and the nitrogen gas only plays a constant temperature role from the cooling nitrogen gas inlet to the cooling nitrogen gas outlet and does not enter the pipeline to participate in the reaction.

[0016] The fixed fluidized bed catalyst evaluation device for cracking crude oil to produce olefins of the present application, the angle between the backfired oil inlet and the fixed fluidized bed reactor is 30-60 degrees, and the outer wall of the pipeline of the backfired oil inlet is provided with a cooling nitrogen gas inlet and a cooling nitrogen gas outlet; the backfired oil inlet is located at the lower end of the reinforced distribution ring.

[0017] The fixed fluidized bed catalyst evaluation device for cracking crude oil to produce olefins of the present application, the vertical distance between the upper edge of the reinforced distribution ring and the bottom of the fixed fluidized bed reactor is located at 10-30 cm above the bottom of the dispersion section; the distance between the reinforced distribution ring and the wall of the fixed fluidized bed reactor is 10-30% of the maximum diameter of the dispersion section; the slope of the reinforced distribution ring is parallel to the slope of the reaction section.

[0018] The fixed fluidized bed catalyst evaluation device for cracking crude oil to produce olefins of the present application, the flange comprises upper and lower flange plates, and a graphite sealing gasket between the upper and lower flange plates; the upper flange plate is provided with a groove, the graphite sealing gasket is placed in the groove, and the graphite sealing gasket and the lower flange plate are connected by bolts.

[0019] The fixed fluidized bed catalyst evaluation device for cracking crude oil to produce olefins of the present application, the thermocouple sleeve is vertically inserted into the inside of the fixed fluidized bed reactor and is parallel to the central axis of the fixed fluidized bed reactor, and the bottom end of the thermocouple sleeve is located at the upper end of the reinforced distribution ring and maintains a distance of 2-10 cm from the reinforced distribution ring.

[0020] The present invention relates to a fixed fluidized bed catalyst evaluation device for crude oil cracking to olefins, wherein the number of reaction oil and gas outlet pipes is 2 to 4 sets, and they are evenly distributed on the flange. Each oil and gas outlet pipe is connected to a filter, and the filter is made of ceramic or powder metallurgy.

[0021] This invention provides a method for evaluating a fixed fluidized bed catalyst for crude oil cracking to olefins. The method includes: loading microsphere catalyst into the catalyst bed of a fixed fluidized bed reactor, wherein the reaction temperature of the fixed fluidized bed reactor is 500–750°C; preheated crude oil is vaporized by an oil pump through a vaporizer and then mixed with high-temperature steam from a steam vaporizer, and the mixture reacts in the catalyst bed of the fixed fluidized bed reactor, along with recycled oil. The resulting oil and gas are separated by a separator, and the gas is analyzed by online chromatography; oxygen is used to regenerate the catalyst after the reaction, and the coke content on the catalyst is determined by a carbon dioxide curve; the catalyst at the inner diameter of the fixed fluidized bed reactor flows upward due to the presence of reinforced distribution rings, while the catalyst at the inner wall of the fixed fluidized bed reactor flows downward, thus circulating the catalyst in the reaction.

[0022] The present invention relates to a method for evaluating a fixed fluidized bed catalyst for crude oil cracking to olefins, wherein the reaction temperature of the fixed fluidized bed reactor is 550–700°C, the preheating temperature of the crude oil is 80–400°C, the temperature of the steam vaporizer is 400–550°C, and the temperature of the recycled oil is 80–120°C.

[0023] The present invention provides a method for evaluating a fixed fluidized bed catalyst for crude oil cracking to olefins, wherein the microsphere catalyst includes, but is not limited to, catalysts prepared by spray molding.

[0024] The present invention relates to a method for evaluating a fixed fluidized bed catalyst for crude oil cracking to olefins, wherein the crude oil can be at least one of oilfield direct-source crude oil and desalted and dehydrated crude oil, or a mixture of crude oil and wax oil, atmospheric residue, and vacuum residue.

[0025] The present invention provides an evaluation method for a fixed fluidized bed catalyst used in crude oil cracking to olefins, wherein the catalyst-to-oil mass ratio in the reaction is 4–20, preferably 6–12; and the mass hourly space velocity of the reaction is 4–20 h⁻¹. -1 The preferred airspeed is 12–16 h. -1 .

[0026] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, the microspherical catalyst is mainly gathered in the dispersion section and the reaction section of the fixed fluidized bed reactor; a fluidizing gas is also needed to be introduced during the reaction for fluidizing the microspherical catalyst in the fixed fluidized bed reactor; the fluidizing gas can be air, nitrogen or water vapor; the fluidizing gas is introduced into the dispersion section through the crude oil inlet and the fluidizing auxiliary gas inlet.

[0027] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, the crude oil and the microspherical catalyst are forced to be fluidized by the reinforced distribution ring during the flow from the dispersion section to the reaction section, and a relatively uniform catalyst dense phase fluidized bed layer is formed in the reaction section; and the catalytic cracking reaction is carried out under specified test conditions; a thermocouple is inserted into the thermocouple sleeve to accurately measure the reaction temperature of the catalytic cracking; during the crude oil feeding reaction, the fluidizing auxiliary gas inlet continuously introduces superheated water vapor or high-temperature nitrogen to prevent the coking and pipeline blockage of the crude oil at high temperature.

[0028] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, the oil gas after the reaction rapidly enters the settling section, and due to the circular truncated cone shape of the settling section, the linear velocity of the oil gas molecules is accelerated, the coexistence time of the intermediate products in the microspherical catalyst dilute phase section is shortened, and the polycondensation reaction between small molecule olefins and other secondary reactions are inhibited.

[0029] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, during the upward movement of the oil gas after the reaction, part of the microspherical catalyst is entrained into the settling section, and as the linear velocity of the fluidizing gas decreases, most of the catalyst particles return to the reaction section, and the oil gas after the reaction is discharged from the fixed fluidized bed reactor through the reaction oil gas outlet pipe.

[0030] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, during the catalytic cracking process, the light gasoline and mixed C4 separated by the condenser separator are introduced into the fixed fluidized bed reactor through the recycled oil inlet, and the products are reacted with the microspherical catalyst again.

[0031] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application, after the catalytic cracking reaction is completed, the crude oil feeding is stopped, the water vapor is continuously introduced, the microspherical catalyst in the reaction section is stripped, and the oil gas in the microspherical catalyst is replaced. After the stripping is completed, the water vapor is stopped, the regenerated oxygen or air is introduced into the reaction section through the crude oil inlet, and the carbon deposited on the surface of the microspherical catalyst is burned off.

[0032] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application uses a fluidizing gas such as air or steam to fluidize the microspherical catalyst, a stripping medium such as steam, stripped oil gas, steam generated in the catalyst regeneration process, and regeneration flue gas, etc., which are all discharged from the fixed fluidized reactor through the reaction oil gas discharge pipe.

[0033] Compared with the prior art, the present application has at least the following beneficial effects:

[0034] (1) The fixed fluidized bed of the prior art generally has an evaluation temperature of 480-560 DEG C. When the evaluation temperature is above 600 DEG C, the coking of the raw material is very serious, which can cause the raw material to be unable to be pumped into the reactor, and the evaluation result cannot be guaranteed. The method and device of the present application overcome the above problems, and the fluidization auxiliary gas temperature protection is provided at the crude oil inlet, so that the crude oil is protected from over-temperature coking under the temperature protection of the auxiliary gas.

[0035] (2) The crude oil raw material itself contains a large amount of gasoline and diesel components, which need a long reaction time and a high reaction temperature to generate ethylene, propylene and butylene. The catalyst is uniformly distributed in the dispersion section and the reaction section of the present application, the bed layer is relatively high, the yield of ethylene, propylene and butylene is high, and the difference of the low-carbon olefin catalyst can be evaluated.

[0036] (3) The method and device of the present application have a reinforced distribution ring at the lower part of the reaction section, which forces the flow of the catalyst, strengthens the mixing of the catalyst and the raw material, and prolongs the reaction time, which is beneficial to the production of low-carbon olefins.

[0037] (4) The method and device of the present application can use light gasoline and C4 as the back-fried oil, which can simulate two-stage riser reactions, and the time of the raw material entering can be controlled. Compared with the kilogram level of catalyst and raw material required in the riser of the prior art, the method and device of the present application only use about 200 grams of catalyst and raw material, which greatly saves the evaluation time and improves the evaluation efficiency.

[0038] (5) The cooling nitrogen gas at the inlet of the back-fried oil can effectively reduce the coking of the raw material caused by high temperature, avoid the pipeline blockage and ensure the long-period operation of the equipment.

[0039] (6) The fixed fluidized bed evaluation method and device of the present application have good repeatability of test data, accurate temperature control, wide adjustment operation range, can adapt to the evaluation test of catalytic cracking reaction performance under high temperature conditions, are suitable for materials with back-fried products, and can provide technical support for the research and development of catalysts for high-temperature catalytic cracking of crude oil to produce low-carbon olefins. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure diagram of the fixed fluidized bed reactor provided in USP6069012.

[0041] Figure 2 A schematic diagram of the structure of the fixed fluidized bed reactor provided for CN2512495.

[0042] Figure 3 A schematic diagram of the structure of a fixed fluidized bed reactor provided in CN200720169455.1.

[0043] Figure 4 This is a cross-sectional view along the axial direction of a fixed fluidized bed catalyst evaluation device for crude oil cracking to olefins, according to an embodiment of the present invention.

[0044] exist Figure 4 In the attached diagram, the following labels are used: 1—addition pipe, 2—flange, 3—thermocouple sheath, 4—enhanced distribution ring, 5—reactor wall, 6—reaction oil and gas outlet pipe, 7—fluidizing auxiliary gas inlet, 8—crude oil inlet, 9—recycled oil inlet, 10—cooling nitrogen inlet, 11—cooling nitrogen outlet, M—settling section, N—reaction section, H—dispersion section.

[0045] Figure 5 This is a schematic flowchart of a fixed fluidized bed catalyst evaluation method for crude oil cracking to olefins according to an embodiment of the present invention.

[0046] exist Figure 5 In the attached figures, the following symbols are used: 12—water vapor, 13—gasifier, 14—oxygen, 15—carbon dioxide meter, 16—separator, 17—online chromatograph Detailed Implementation

[0047] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0048] Figure 4 This is an axial cross-sectional view of a fixed fluidized bed catalyst evaluation device for crude oil cracking to olefins, according to an embodiment of the present invention. The fixed fluidized bed reactor consists of a settling section M, a reaction section N, and a dispersion section H from top to bottom.

[0049] The fixed fluidized bed reactor has a flange 2 at the top, on which are mounted a dosing pipe 1, a thermocouple sheath 3, and a reaction oil / gas outlet pipe 6. All three pipes lead into the interior of the fixed fluidized bed reactor. The settling section M is a frustum-shaped cone, wider at the bottom than the top, with an angle of 30-60 degrees to the horizontal. The ratio of its diameter to the diameter of its upper end is preferably 1-3:1; the ratio of its height to its upper end diameter is preferably 1-10:1. The reaction section N is an inverted cone, wider at the top than the bottom, with the ratio of its height to its upper end diameter preferably 1-10:1. A reinforcing distribution ring 4 is located in the center of the reaction section N, with a gap between it and the wall of the fixed fluidized bed reactor. The distance of this gap is preferably 10-30% of the maximum diameter of the dispersion section H. The crude oil inlet 8 is located at the bottom center of the fixed fluidized bed reactor, vertically inserted into the bottom, and has a nozzle at the outlet. The fluidization auxiliary gas inlet 7 is a casing type, and the auxiliary gas passes through the outer layer of the crude oil inlet pipe 8. The dispersion section H area also has a return oil inlet, and the nitrogen pipeline is surrounded by the return oil pipeline. The nitrogen from the cooling nitrogen inlet 10 to the cooling nitrogen outlet 11 only plays a constant temperature role and does not enter the pipeline to participate in the reaction.

[0050] The recycle oil inlet 9 is at an angle of 30 to 60 degrees to the reactor. There is a cooling nitrogen inlet 10 and a cooling nitrogen outlet 11 on the outer wall of the pipeline of the recycle oil inlet 9. The recycle oil inlet 9 is located at the lower end of the enhanced distribution ring 4.

[0051] The vertical distance between the upper edge of the enhanced distribution ring 4 and the bottom of the fixed fluidized bed reactor is preferably 10-30 cm above the bottom of the dispersion section H. The distance between the enhanced distribution ring 4 and the reactor wall 5 is 10-30% of the maximum diameter of the dispersion section H. The inclined surface of the enhanced distribution ring 4 is parallel to the inclined surface of the reaction section N.

[0052] The fixed fluidized bed reactor is provided with flange 2 at the top. Flange 2 may include upper and lower flanges and a graphite gasket located between the upper and lower flanges. The upper flange is machined into a groove of a certain diameter, and the graphite gasket is placed in the groove. The graphite gasket is used to tightly fix the upper flange to the lower flange with bolts.

[0053] The thermocouple sheath 3 is parallel to the central axis of the fixed fluidized bed reactor and is inserted vertically into the fixed fluidized bed reactor. Its bottom end is preferably located at the upper end of the reinforcing distribution ring 4 and is kept at a certain distance from the reinforcing distribution ring 4, preferably 2 to 10 cm.

[0054] The number of reaction oil and gas outlet pipes 6 is not limited to 2 to 4 sets, which are evenly distributed on the flange 2. Each oil and gas outlet pipe 6 is connected to a filter, which can be made of ceramic or powder metallurgy materials.

[0055] The fixed fluidized bed catalyst evaluation method for cracking crude oil to produce olefins of the present application comprises:

[0056] The microspherical catalyst is loaded into the fixed fluidized bed reactor, the reaction temperature of the reactor is 500-750 DEG C, and the preferred reaction temperature is 550-700 DEG C; the preheated crude oil is vaporized by the oil pump through the vaporization furnace 13, mixed with the high-temperature water vapor 12 from the water vaporization furnace, and then passes through the catalyst bed layer, and the back-refined oil 9 also participates in the reaction at the same time; the oil gas after the reaction is separated by the separator 16, and the gas enters the online chromatograph for analysis; the catalyst is regenerated by using oxygen after the reaction, and the coke content on the catalyst is obtained from the carbon dioxide curve; the catalyst at the inner diameter of the fixed fluidized bed reactor flows upward due to the existence of the strengthening distribution ring 4, and the catalyst at the inner wall of the fixed fluidized bed reactor flows downward to participate in the reaction.

[0057] The evaluation method of the present application does not particularly limit the preparation method of the microspherical catalyst, and the microspherical catalyst can be prepared by a spray forming method.

[0058] The evaluation method of the present application, the crude oil can be at least one of the directly collected crude oil from an oil field, desalted and dewatered crude oil, or a mixture of crude oil and wax oil, atmospheric residue, and vacuum residue.

[0059] The evaluation method of the present application, the preheating temperature of the crude oil vaporization furnace is 80-400 DEG C, the temperature of the water vaporization furnace is 400-550 DEG C, the temperature of the back-refined oil is 80-120 DEG C, the mass ratio of the catalyst to the oil is 4-20, the preferred mass ratio of the catalyst to the oil is 6-12, and the mass space velocity is 4-20 h -1 , and the preferred space velocity is 12-16 h -1 .

[0060] The evaluation method of the present application, the catalyst mainly gathers in the bottom dispersion section H and the reaction section N of the fixed fluidized bed reactor. The fluidization gas can be air, nitrogen or water vapor. The dispersion section H is sent into the fixed fluidized bed reactor through the crude oil inlet 8 and the fluidization auxiliary gas inlet 7, and is used to fluidize the catalyst in the fixed fluidized bed reactor.

[0061] The evaluation method of the present application, the raw material is mixed with the preheated and superheated water vapor 12, enters the crude oil inlet 8 and flows upward, enters the fixed fluidized bed reactor and is rapidly vaporized, fully contacts with the catalyst in the dispersion section H and the reaction section N, and flows upward.

[0062] The evaluation method of the present application forces the crude oil and catalyst to be fluidized by the reinforced distribution ring 4 during the flow from the dispersion section H to the reaction section N, and forms a relatively uniform dense phase flow bed of catalyst in the reaction section; and carries out catalytic cracking reaction under the specified test conditions; the thermocouple is inserted into the thermocouple sleeve 3 to accurately measure the reaction temperature of the catalytic cracking; and the fluidization auxiliary gas inlet 7 is always connected to the superheated steam or high-temperature nitrogen to prevent the coking and pipeline blockage of the crude oil at high temperature.

[0063] The evaluation method of the present application rapidly enters the oil gas generated by the reaction into the settling section M, the oil gas molecules accelerate due to the circular truncated cone shape of the settling section, the coexistence time of the intermediate products in the catalyst dilute phase section is shortened, and the polycondensation reaction between small molecule olefins and other secondary reactions are inhibited.

[0064] The evaluation method of the present application carries out the reaction oil gas from bottom to top, part of the catalyst is entrained into the settling section, most of the catalyst particles return to the reaction section as the linear velocity of the fluidization gas decreases, and the reaction oil gas is discharged from the reactor through the reaction oil gas outlet pipe 6.

[0065] The evaluation method of the present application carries out the catalytic cracking process, the light gasoline and mixed C4 separated by the condenser 16 are introduced into the back-refining oil inlet, and the products are introduced into the fixed fluidized bed reactor through the back-refining oil inlet 9 again to react with the cracking catalyst.

[0066] The evaluation method of the present application stops the introduction of the crude oil after the catalytic cracking reaction is completed, continues to introduce the steam, strips the catalyst in the reaction section, and replaces the oil gas in the catalyst. After the stripping is completed, the steam is stopped, the regeneration oxygen or air is introduced through the crude oil inlet 8, enters the reaction section N, and burns off the carbon deposit on the surface of the catalyst.

[0067] The evaluation method of the present application uses the fluidization gas such as air or steam, the stripping medium such as steam, the stripped oil gas, the steam generated in the catalyst regeneration process, and the regeneration flue gas, which are all discharged from the fixed fluidized bed reactor through the reaction oil gas outlet pipe 6.

[0068] The following examples further illustrate the present application, but the following examples do not limit the scope of the present application.

[0069]

Example 1

[0070] The fixed fluidized bed reactor with the structure shown in the drawing and the Figure 4 Figure 5 ​Evaluation method and test conditions: The feedstock oil is crude oil desalted and dehydrated from Lanzhou Petrochemical, the catalyst is a special catalyst for low-carbon olefins, the catalyst-to-oil ratio is 5, and the reaction temperatures are 530℃, 550℃, 570℃, 590℃, 610℃, and 630℃. The fluidizing gas during the reactor heating process is nitrogen, and the fluidizing gas after the reactor reaches the set temperature is nitrogen. The fluidization auxiliary gas is nitrogen.

[0071] The product distribution is shown in Table 1. As can be seen from Table 1, when the temperature increased from 530℃ to 630℃, the gasoline yield decreased from 52.78% to 40.88%, a decrease of 11.9 percentage points, while the coke yield increased from 7.93% to 10.24%, an increase of 2.31 percentage points. The ethylene + propylene + butene ratio increased from 15.16% to 25.88%. This indicates that the reactor is effective in evaluating the catalytic cracking reaction performance at different temperatures.

[0072] Table 1 Effect of different temperatures on low-carbon olefin-specific catalysts

[0073]

[0074]

[0075]

Example 2

[0076] use Figure 4 The structure of the fixed fluidized bed reactor shown is as follows: Figure 5 Evaluation method and test conditions: The feed oil is crude oil desalted and dehydrated from Lanzhou Petrochemical, the catalyst is low-carbon olefin special catalyst 2, the temperature is 570℃, the catalyst-to-oil ratio is 7.5~15, the fluidizing gas after the reactor reaches the set temperature is nitrogen, and the fluidizing auxiliary gas is nitrogen.

[0077] The product distribution is shown in Table 2. As can be seen from Table 2, when the catalyst-to-oil ratio increased from 7.5 to 15, the gasoline yield increased from 30.62% to 41.32%, and the coke yield increased from 7.12% to 11.71%. This indicates that the reactor can be used to evaluate the catalytic cracking reaction performance under different catalyst-to-oil ratios.

[0078] Table 2. Effect of different catalyst-to-oil ratios on low-carbon olefin-specific catalysts

[0079]

[0080]

[0081]

Example 3

[0082] use Figure 4 The structure of the fixed fluidized bed reactor shown is as follows: Figure 5Evaluation method and test conditions: The feed oil is crude oil desalted and dehydrated from Ningxia Petrochemical, the catalyst is low-carbon olefin special catalyst 3, the temperature is 570℃~690℃, the catalyst-to-oil ratio is 7.5, and the fluidizing gas after the reactor reaches the set temperature is nitrogen, and the fluidizing auxiliary gas is nitrogen.

[0083] The product distribution is shown in Table 3. As can be seen from Table 3, at reaction temperatures ranging from 570℃ to 690℃, the gasoline yield decreased from 40.17% to 26.94%, while the coke yield increased from 4.42% to 8.51%. The yield of ethylene + propylene + butene increased from 29.49% to 38.99%. This indicates that the reactor can be used to evaluate the catalytic cracking reaction performance at different temperatures, with significant differences.

[0084] Table 3. Effect of different temperatures on catalysts specifically designed for low-carbon olefins

[0085]

[0086]

[0087]

Example 4

[0088] use Figure 4 The structure of the fixed fluidized bed reactor shown is as follows: Figure 5 Evaluation method and test conditions: The feed oil is crude oil desalted and dehydrated from Ningxia Petrochemical, the catalyst is a special catalyst for low-carbon olefins, the temperature is 650℃, the catalyst-to-oil ratio is 15.0, and the fluidizing gas after the reactor reaches the set temperature is nitrogen, and the fluidizing auxiliary gas is nitrogen.

[0089] The product distribution is shown in Table 4. As can be seen from Table 4, the coke yield increased from 4.86% to 7.30%. The combined yield of ethylene, propylene, and butene trimerenes was the highest at 43.76%, while the gasoline yield decreased from 32.77% to 32.35%. This indicates that the reactor can be used to evaluate the catalytic cracking performance with different catalysts, revealing significant differences in catalyst performance.

[0090] Table 4. Effects of different low-carbon olefin-specific catalysts on reaction results

[0091]

[0092]

[0093]

Example 5

[0094] use Figure 4 The structure of the fixed fluidized bed reactor shown is as follows: Figure 5Evaluation method and test conditions: The feedstock is crude oil desalted and dehydrated from Ningxia Petrochemical, the catalyst is a special catalyst for low carbon olefins, the temperature is 650℃, the catalyst-to-oil ratio is 15.0, the fluidizing gas after the reactor reaches the set temperature is nitrogen, the fluidizing auxiliary gas is nitrogen, and the recycled oil is light gasoline + C4 component (1:1).

[0095] The product distribution is shown in Table 5. As can be seen from Table 5, the gasoline yield decreased from 32.77% to 29.25%, while the coke yield increased from 4.86% to 5.79%. The combined yield of ethylene, propylene, and butene trimerenes was the highest at 44.09%. This indicates that the reactor can be used to evaluate the catalytic cracking reaction performance under these conditions, and the catalysts show significant differences.

[0096] Table 5. Effects of different low-carbon olefin-specific catalysts on reaction results

[0097] Catalyst Blank Special agent 9 Crude oil feedstock NingXia NingXia Temperature, °C 650.0 650.0 Agent to oil ratio 15.00 15.00 Coke 4.86 5.79 Dry gas 17.11 18.24 Ethylene 9.92 12.32 Propylene 19.46 25.21 C4 olefins 11.61 6.56 Gasoline 32.77 29.25 Diesel 8.59 8.67 Heavy oil 2.52 2.98 Total trienes 40.99 44.09

[0098] Comparative Example 1

[0099] The difference from Example 3 is that, as in Example 3, the following is used: Figure 3 The fixed fluidized bed reactor provided by CN200720169455.1, with reaction conditions the same as in Example 3, yields the following product distribution, which is listed in Table 6. As can be seen from Table 6, compared to Comparative Example 1, under the same test conditions, the present invention increases ethylene by 1.88%, propylene by 2.62%, and the total yield of trienes by 4.38%, while the yields of gasoline and C4 are essentially the same, demonstrating superior performance in evaluating low-carbon olefins.

[0100] Table 6 Evaluation data of Example 3 and Comparative Example 1

[0101]

[0102]

[0103] Obviously, the above embodiments are merely illustrative examples for clarity and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A fixed fluidized bed catalyst evaluation device for crude oil cracking to olefins, characterized in that, include: The fixed fluidized bed reactor consists of a settling section, a reaction section, and a dispersion section from top to bottom. A flange is located at the top of the reactor, and the dosing pipe, thermocouple sheath, and reaction oil / gas outlet pipe on the flange are all connected to the interior of the reactor. The settling section is shaped like a frustum, wider at the bottom and narrower at the top. The angle between the frustum and the horizontal direction is 30-60 degrees, and the ratio of its diameter to the diameter of its upper end is 1-3:1; the ratio of the height of the frustum to the diameter of its upper end is 1-10:

1. The reaction section is shaped like an inverted cone, wider at the top and narrower at the bottom, with the ratio of its height to its diameter of its upper end also being 1-10:

1. A centrally located reinforcing distribution ring is provided, with a gap between the reinforcing distribution ring and the wall of the fixed fluidized bed reactor. The distance of the gap is 10-30% of the maximum diameter of the dispersion section. The crude oil inlet is located at the center of the bottom of the fixed fluidized bed reactor and is vertically inserted into the bottom of the fixed fluidized bed reactor. A nozzle is provided at the outlet. The fluidization auxiliary gas inlet is a sleeve type, and the auxiliary gas passes through the outer layer of the crude oil inlet pipe. The dispersion section area also includes a recycle oil inlet and a nitrogen pipeline. The nitrogen gas from the cooling nitrogen inlet to the cooling nitrogen outlet only serves to maintain the temperature and does not enter the pipeline to participate in the reaction.

2. The apparatus according to claim 1, characterized in that, The angle between the recycled oil inlet and the fixed fluidized bed reactor is 30 to 60 degrees. The outer wall of the recycled oil inlet pipeline is provided with a cooling nitrogen inlet and a cooling nitrogen outlet. The recycled oil inlet is located at the lower end of the enhanced distribution ring.

3. The apparatus according to claim 1, characterized in that, The vertical distance between the upper edge of the enhanced distribution ring and the bottom of the fixed fluidized bed reactor is 10-30 cm above the bottom of the dispersion section; the distance between the enhanced distribution ring and the wall of the fixed fluidized bed reactor is 10-30% of the maximum diameter of the dispersion section; the inclined surface of the enhanced distribution ring is parallel to the inclined surface of the reaction section.

4. The apparatus according to claim 1, characterized in that, The flange includes upper and lower flanges, and a graphite gasket located between the upper and lower flanges; the upper flange has a groove, the graphite gasket is placed in the groove, and the graphite gasket is connected to the lower flange by bolts.

5. The apparatus according to claim 1, characterized in that, The thermocouple sheath is vertically inserted into the fixed fluidized bed reactor and is parallel to the central axis of the fixed fluidized bed reactor. The bottom end of the thermocouple sheath is located at the upper end of the reinforcing distribution ring and is 2-10 cm away from the reinforcing distribution ring.

6. The apparatus according to claim 1, characterized in that, The number of reaction oil and gas outlet pipes is 2 to 4 sets, and they are evenly distributed on the flange. Each oil and gas outlet pipe is connected to a filter, and the filter is made of ceramic or powder metallurgy.

7. A method for evaluating a fixed fluidized bed catalyst used in crude oil cracking to olefins, characterized in that, The method, employing the apparatus according to any one of claims 1-6, comprises: Microsphere catalysts are loaded into the catalyst bed of a fixed fluidized bed reactor, with a reaction temperature of 500–750°C. Preheated crude oil is vaporized in a vaporizer via an oil pump and then mixed with high-temperature steam from a steam vaporizer. The mixture then reacts in the catalyst bed of the fixed fluidized bed reactor, along with recycled oil. The resulting oil and gas are separated by a separator, and the gas is analyzed by online chromatography. After the reaction, oxygen is used to regenerate the catalyst, and the coke content on the catalyst is determined by a carbon dioxide curve. The catalyst at the inner diameter of the fixed fluidized bed reactor flows upward due to the presence of enhanced distribution rings, while the catalyst at the inner wall of the reactor flows downward, thus circulating the catalyst in the reaction.

8. The method according to claim 7, characterized in that, The reaction temperature of the fixed fluidized bed reactor is 550~700℃, the preheating temperature of the crude oil is 80~400℃, the temperature of the steam vaporizer is 400~550℃, and the temperature of the recycled oil is 80~120℃.

9. The method according to claim 7, characterized in that, The crude oil is at least one of oilfield direct-source crude oil and desalted and dehydrated crude oil, or a mixture of crude oil and wax oil, atmospheric residue, and vacuum residue.

10. The method according to claim 7, characterized in that, The mass ratio of agent to oil in the reaction is 4-20; the mass hourly space velocity of the reaction is 4-20 h⁻¹. -1 .

11. The method according to claim 10, characterized in that, The mass ratio of the agent to oil in the reaction is 6-12.

12. The method according to claim 10, characterized in that, The mass hourly space velocity of the reaction is 12-16 h⁻¹. -1 .

13. The method according to claim 7, characterized in that, The microsphere catalyst is mainly concentrated in the dispersion section and reaction section of the fixed fluidized bed reactor; during the reaction process, fluidizing gas is also introduced to fluidize the microsphere catalyst in the fixed fluidized bed reactor; the fluidizing gas is introduced into the dispersion section through the crude oil inlet and the fluidizing auxiliary gas inlet.

14. The method according to claim 13, characterized in that, The fluidizing gas is air, nitrogen, or water vapor.

15. The method according to claim 7, characterized in that, During the reaction, light gasoline and mixed C4 separated by the condenser are introduced into the recycle oil inlet. The light gasoline and mixed C4 then enter the fixed fluidized bed reactor and react together with the microsphere catalyst.

16. The method according to claim 7, characterized in that, After the reaction is completed, the crude oil supply is stopped, and steam is continued to be introduced to strip the microsphere catalyst in the reaction section, displacing the oil and gas in the microsphere catalyst. After the stripping is completed, the steam supply is stopped, and regenerated oxygen or air is introduced through the crude oil inlet into the reaction section to burn off the carbon deposits on the surface of the microsphere catalyst.

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