A catalytic cracking unit feeding system and feeding method

Abstract

The present invention provides a catalytic cracking device feeding system and feeding method, the catalytic cracking device feeding system includes: a regeneration unit and a fresh catalyst feeding unit; the regeneration unit includes a shell containing a catalyst dense phase bed and a catalyst dilute phase bed; the bottom of the shell is provided with a regenerated catalyst collecting tank; the fresh catalyst feeding unit includes: a pulse automatic feeder and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, the gas outlet and the fresh catalyst outlet are connected through a feed pipe and the inside of the regeneration unit, and the fresh catalyst outlet of the feed pipe is located at a specific position relative to the regenerated catalyst collecting tank. Compared with the traditional feeding system, the feeding system of the present invention can effectively reduce the loss of fresh catalyst and improve the activity of the catalyst.

Description

Technical Field

[0001] The invention relates to the field of catalytic cracking devices, and in particular to a feeding system and a feeding method for a catalytic cracking device. Background Art

[0002] When the catalytic cracking unit is in production and operation, as the catalyst continuously circulates in the system and participates in the cracking reaction, it will cause problems such as catalyst wear and decreased activity. Therefore, it is necessary to regularly add a certain amount of fresh catalyst to the unit to maintain the quality of the system catalyst's reaction activity and the stability of the system's storage capacity, so as to achieve smooth operation of the unit. This timed and quantitative addition operation method is usually called small-scale feeding.

[0003] The traditional small-scale feeding system uses pneumatic conveying to deliver fresh catalyst from the fresh catalyst storage tank to the dense phase bed of the regeneration unit. After entering the regeneration unit, the fresh catalyst is mixed with the regenerated catalyst, and most of the regenerated flue gas or air is removed by the regeneration unit. Then, the fresh catalyst is transported to the (riser) reactor to contact and react with the crude oil. However, the traditional dosing system does not realize the injection state of the fresh catalyst, the specific input position and layout of the fresh catalyst in the regeneration unit, etc. Therefore, the traditional dosing system has a serious problem of thermal collapse and crushing when the fresh catalyst is added, resulting in a large amount of ineffective loss of the fresh catalyst, and has an adverse effect on the quality of the system catalyst activity, etc., increasing the cost of using the fresh catalyst.

[0004] Patent US4220622A published in 1980 records a fluidized particle or catalyst regeneration device, which mentions a fresh catalyst storage, a buffer zone, and a regenerator, but does not fully consider the relevant equipment for stabilizing the flow, whether the fresh catalyst is in a fluidized state, and does not record the reasonable addition position and arrangement method of the fresh catalyst in the regenerator, as well as the thermal collapse and consumption of the fresh catalyst when it is added.

[0005] Patent CN205627897U published in 2016 relates to a catalytic cracking reaction-regeneration system for preventing thermal collapse of catalysts. By setting the catalyst addition pipeline downstream of the cold regenerated catalyst pipeline and / or the catalyst pipeline to be regenerated, before entering the regenerator under high temperature conditions, the newly added normal temperature catalyst can first contact with the relatively low temperature regenerated catalyst / or the catalyst to be regenerated to achieve the purpose of pre-heating, and then enter the high temperature regenerator to avoid the newly added (normal temperature) catalyst directly entering the high temperature regenerator. When the temperature difference is too large, the serious thermal collapse phenomenon occurs. However, the optimization scheme process is relatively complicated, and the difficulty of implementation under the working condition of solid catalyst fluidization increases, resulting in poor system operation stability. At the same time, the scheme still cannot avoid the test of fresh catalyst breaking under high temperature conditions, but only alleviates this trend, so it cannot fundamentally solve the problem of fresh catalyst thermal collapse under high temperature conditions. And the scheme still does not consider the influence of the stable injection of its additives and the uniform addition of fresh catalyst supplement on the quality of cracking reaction, so it has not been widely used in catalytic cracking process so far.

[0006] Patent CN206444579U published in 2017 discloses a catalyst metering feeding device and a catalyst metering feeding system, including a catalyst tank, a buffer tank, and a regenerator. It only solves the problem of inaccurate metering of the amount of solid particle catalyst added in the prior art, but does not solve the stable injection of fresh catalyst, the specific delivery position / arrangement method of the fresh catalyst in the regenerator, and the thermal collapse and ineffective consumption of the fresh catalyst.

[0007] In the patent CN111321000B published in 2018, after the fresh catalyst is injected through the degassing tank, it does not need to pass through the regenerator before the catalytic cracking reaction, which reduces the possibility of thermal collapse of the fresh catalyst and avoids the situation where the fresh catalyst is directly unloaded from the regenerator before the catalytic cracking reaction. That is, in order to reduce the loss caused by factors such as thermal collapse of the fresh catalyst, the method of directly injecting the fresh catalyst through the degassing tank without passing through the regenerator before the catalytic cracking reaction is adopted. However, this scheme will cause the part of the fresh catalyst with extremely high activity and low temperature to directly participate in the reaction of the crude oil, which is easy to cause a negative impact on the effect of the reaction product (condensation reaction under high activity conditions-coking), resulting in an increase in the coke yield. At the same time, this scheme does not take into account the problem of uniform and stable injection of fresh catalyst, and the pulse-type dosing method through the injection method in the degassing tank, and the pulse-type conveying wind it carries will cause the stable circulation of the system regenerated catalyst. The production fluctuations and operation risks, so this scheme has not been widely used in catalytic cracking processes.

[0008] Patent CN220514128U published in 2023 discloses an automatic catalyst feeding system for a catalytic cracking unit, including a fresh catalyst tank and a delivery pump. The bottom of the fresh catalyst tank is connected to the metering bin through a feed pipeline. The metering bin is used for loading and metering the delivery amount each time. However, this solution only solves the technical problem of inaccurate addition of solid particulate catalyst existing in the prior art, but does not solve the appropriate addition position and layout of the fresh catalyst in the regenerator and the thermal collapse and ineffective consumption faced by the fresh catalyst. Summary of the invention

[0009] The present invention provides a catalytic cracking unit feeding system, which can effectively reduce the loss of fresh catalyst and improve its catalyst activity and other quality problems compared with the traditional feeding system. In addition, since the feeding position of the fresh catalyst is optimized, the internal fluidization field and temperature field of the fresh catalyst feed and the collection tank feed in the corresponding regenerator are changed, so the feed pipe of the fresh catalyst is matched and optimized to improve the corrosion environment, high temperature resistance and wear resistance of the fresh catalyst feed pipe in the regenerator.

[0010] The present invention also provides a feeding method using the above-mentioned catalytic cracking unit feeding system.

[0011] In a first aspect, a catalytic cracking unit feeding system comprises: a regeneration unit and a fresh catalyst feeding unit; the regeneration unit comprises a shell containing a catalyst dense phase bed and a catalyst dilute phase bed; a regenerated catalyst collecting tank is provided at the bottom of the shell;

[0012] The fresh catalyst feeding unit comprises: a pulse automatic feeder and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, the gas outlet and the fresh catalyst outlet are connected through a feed pipe and the inside of the regeneration unit, and the fresh catalyst outlet of the feed pipe satisfies the following formulas 1 to 2:

[0013] 0≤m≤0.5R Formula 1,

[0014] 0.1H≤h1≤0.6H Formula 2;

[0015] Among them, the top of the catalyst dense phase bed is a circular cross-section, R is the radius of the circular cross-section; m is the horizontal straight line distance from the fresh catalyst outlet of the feed pipe to the perpendicular line of the center of the circle at the entrance of the regenerated catalyst collecting tank; H is the vertical distance between the circular cross-section and the plane where the entrance of the regenerated catalyst collecting tank is located; h1 is the vertical distance from the plane where the entrance of the regenerated catalyst collecting tank is located to the plane where the fresh catalyst outlet of the feed pipe is located.

[0016] Further, the flow stabilizing element includes a swirl pot and a fluidizing pot; the swirl pot is connected to the pulse automatic feeder through a pipeline, an air inlet valve is provided on the pipeline, the gas outlet is arranged at the top of the swirl pot, the fluidizing pot includes a fresh catalyst inlet and the fresh catalyst outlet, and the fresh catalyst inlet is connected to the swirl pot;

[0017] And / or, a main air distribution pipe is provided at the lower part of the catalyst dense phase bed for introducing oxygen-containing gas into the regeneration unit.

[0018] Further, the portion of the feed pipe extending to the interior of the housing of the regeneration unit and / or the main air distribution pipe comprises: a substrate and a coating disposed on the surface of the substrate;

[0019] The substrate meets the following conditions:

[0020] At room temperature, the V-notch impact toughness of the matrix is ​​5.0~6.0J / cm 2 , 750℃ tensile properties meet the following requirements: tensile strength ≥ 300MPa, yield strength ≥ 200MPa, elongation ≥ 30%;

[0021] The coating meets the following conditions:

[0022] The hardness of the coating is ≥50HRC, and the bonding strength between the coating and the substrate is ≥50MPa.

[0023] Furthermore, the material of the matrix is ​​an iron alloy, in which M 23 C6 type carbide; the coating comprises WC, Cr3C2, Co and Mo;

[0024] Further, the ferroalloy comprises, by mass percentage, Cr: 15-17%, W: 9-10%, Co: 6-8%, Mo: 3-5%, Ta+Nb: 2-3%, C: 1-2% and the rest Fe; and the ferroalloy does not contain Ni;

[0025] And / or, in the coating, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2-3:1;

[0026] And / or, in the coating, the average particle sizes of WC and Cr3C2 are each independently 50-150 nm, and the average particle sizes of Co and Mo are each independently 0.5-1.0 μm.

[0027] Furthermore, the thickness of the coating is 50-150 μm.

[0028] In a second aspect, the present invention provides a method for feeding using the above-mentioned catalytic cracking unit feeding system, comprising the following steps:

[0029] The fresh catalyst is automatically pressed out by a pulse automatic feeder and then transported to the flow stabilizing member by a transport gas, so that the fresh catalyst and the transport gas are input from the fresh catalyst outlet of the feed pipe to a position close to the regenerated catalyst collecting tank in the regeneration unit, the fresh catalyst and the regenerated catalyst are mixed, and the mixed mixture is continuously transported to the reaction cracking unit through a dedicated catalyst circulation pipeline.

[0030] Furthermore, the single feeding weight of the pulse automatic feeder is 1-150 kg, and the interval time is 5 min-1 h; when conveying to the flow stabilizing member, the feeding speed of the fresh catalyst is 50-500 kg / h.

[0031] Furthermore, the top pressure of the regeneration unit is 0.2-0.3 MPa, the catalyst dilute phase bed temperature of the regeneration unit is 675-685°C, and the catalyst dense phase bed temperature of the regeneration unit is 660-670°C.

[0032] The catalytic cracking unit feeding system provided by the present invention, by arranging a pulse automatic feeder, a flow stabilizer, and the relative relationship between the fresh catalyst outlet and the regenerated catalyst inlet, on the one hand effectively reduces the high-temperature thermal collapse phenomenon of the fresh catalyst in the regeneration unit, significantly reduces the loss when the fresh catalyst is added, thereby achieving the purpose of reducing costs and increasing efficiency; on the other hand, it avoids the problems of periodic impact interference and fluctuation of the fresh catalyst during the feeding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0034] Figure 1 A catalytic cracking unit feeding system according to a specific embodiment of the present invention;

[0035] Figure 1 Among them, 001: shell, 0011: catalyst dense phase bed, 0012: catalyst dilute phase bed, 002: regenerated catalyst collection tank, 003: pulse automatic feeder, 004: feed pipe including fresh catalyst outlet, 005: flow stabilization tank, 0051: pipeline, 0052: air inlet valve, 0053: flow control valve, 0054: storage volume control table, 0055: pressure display and control table, 006: fluidized tank, 007: main air distribution pipe;

[0036] Figure 2 A schematic diagram of the position coordinates of a fresh catalyst outlet according to a specific embodiment of the present invention;

[0037] Figure 2Middle: 402: fresh catalyst outlet position of the feed pipe, 403: regenerated catalyst collection tank inlet position;

[0038] Figure 3 It is a schematic diagram of the relative position relationship between the fresh catalyst outlet and the regenerated catalyst collecting tank inlet in a plane of the present invention;

[0039] Figure 3 Middle: 402: fresh catalyst outlet position of feed pipe, 403: regenerated catalyst collecting tank inlet position, 401: fresh catalyst outlet position of conventional feed pipe, 0011: catalyst dense phase bed, 0012: catalyst dilute phase bed, 002: regenerated catalyst collecting tank, 007: main air distribution pipe;

[0040] Figure 4 This is a schematic diagram of the relative position relationship between the fresh catalyst outlet and the regenerated catalyst collecting tank in the regeneration unit of the present invention;

[0041] Figure 4 Middle: 402: fresh catalyst outlet position of the feed pipe, 403: regenerated catalyst collecting tank inlet position, 401: fresh catalyst outlet position of the conventional feed pipe.

[0042] The above drawings have shown clear embodiments of the present invention, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present invention in any way, but to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Fresh catalyst is added to the catalytic cracking system composed of a reactor and a regeneration unit (hereinafter referred to as the reactor-regeneration system), and there is a serious high-temperature crushing phenomenon. The crushed fresh catalyst dust is discharged into the atmosphere along with the regeneration flue gas, which not only pollutes the environment but also leads to a great waste of resources. In view of the above problems, the present invention adopts the following technical solutions to reduce the catalyst unit consumption of the device, improve the catalyst activity, and improve the operability of the dosing method:

[0045] In a first aspect, the present invention provides a catalytic cracking unit feeding system, Figure 1A catalytic cracking unit feeding system according to a specific embodiment of the present invention comprises: a regeneration unit and a fresh catalyst feeding unit; the regeneration unit comprises a shell 001 containing a catalyst dense phase bed 0011 and a catalyst dilute phase bed 0012; a regenerated catalyst collecting tank 002 is provided at the bottom of the shell;

[0046] The fresh catalyst feeding unit comprises: a pulse automatic feeder 003 and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, the gas outlet and the fresh catalyst outlet are connected to the inside of the regeneration unit through a feed pipe 004 (see attached for details). Figure 2 ), the fresh catalyst outlet of the feed pipe satisfies the following equations 1 to 2:

[0047] 0≤m≤0.5R Formula 1,

[0048] 0.1H≤h1≤0.6H Formula 2;

[0049] Among them, the top of the catalyst dense phase bed is a circular cross-section, R is the radius of the circular cross-section; m is the horizontal straight line distance from the fresh catalyst outlet of the feed pipe to the perpendicular line of the center of the circle at the entrance of the regenerated catalyst collecting tank; H is the vertical distance between the circular cross-section and the plane where the entrance of the regenerated catalyst collecting tank is located; h1 is the vertical distance from the plane where the entrance of the regenerated catalyst collecting tank is located to the plane where the fresh catalyst outlet of the feed pipe is located.

[0050] It should be noted that the size and position of the circular cross-section at the top of the catalyst dense phase bed can be determined by technicians according to the specific regenerator design conditions. For details, please refer to Figure 3 shown.

[0051] It can be understood that the regenerated catalyst collection tank 002 is used to collect the catalyst to be regenerated in the regenerator after regeneration and modification, so as to be subsequently transported to the reactor for use; in addition, the fresh catalyst outlets involved in Formulas 1 to 2 are all fresh catalyst outlets of the feed pipe.

[0052] Further, the m satisfies: 0.1R≤m≤0.4R, and the h1 satisfies: 0.25H≤h1≤0.5H; preferably, the m satisfies: 0.1R≤m≤0.3R, and the h1 satisfies: 0.25H≤h1≤0.4H; more preferably, the m satisfies: 0.1R≤m≤0.2R, and the h1 satisfies: 0.25H≤h1≤0.3H.

[0053] Figure 4It is a schematic diagram of the relative position relationship between the fresh catalyst outlet of the feed pipe and the regenerated catalyst collecting tank in the regeneration unit of the present invention; it should be noted that, from the perspective of the top view, the fresh catalyst outlet position 402 of the feed pipe does not necessarily fall on the line connecting the center of the inlet plane of the regenerated catalyst collecting tank and the center of the corresponding regenerator shell, that is, from the perspective of the top view, the fresh catalyst outlet position 402 of the feed pipe can fall on the line formed by the two centers of the circle, or outside the line.

[0054] There are two main reasons for the breakage of fresh catalyst and loss of catalyst during dosing in the reactor-reactor system caused by the traditional dosing system:

[0055] On the one hand, thermal collapse under high temperature conditions is the main reason for the breakage of fresh catalysts, because fresh catalysts are added to the catalyst dense phase bed of the regeneration unit under high temperature (660~685℃) conditions at room temperature. Although the performance of high temperature treatment has been taken into consideration in the production of fresh catalysts, the existing production processes and materials are still unable to completely solve the thermal collapse phenomenon. Therefore, when a large amount of fresh catalyst is added to the regeneration unit, the rapid temperature rise will still cause severe thermal collapse and breakage, resulting in many fresh catalyst fine powders not participating in the catalytic cracking reaction, but being discharged along with the regenerated flue gas.

[0056] On the other hand, in the fluidized coking mode in the conventional regeneration unit (see Appendix Figure 3 and 4 ), the position 401 of the fresh catalyst outlet of the traditional feed pipe aggravates the loss of fresh catalyst: in the regenerator, under the fluidization and burning agitation of large main air volume, the dense phase bed of the catalyst in the entire regenerator presents a violent upward impact fluidization mode (the air from the main fan is distributed through the nozzle of the main air distribution pipe at the bottom of the regeneration unit to form a bubbling flow under violent combustion conditions. When the large bubbles reach the dense phase bed near the transition section, the large bubbles burst and erupt due to the decrease in bed density). The fresh catalyst just added is immediately and completely carried and moves upward in this state. In this process, the fresh catalyst On one hand, it is crushed (including wear) by the high temperature of intense combustion, and on the other hand, it moves upward in fluidization. A considerable part of the fresh catalyst (≤30um fine powder particles) that has not undergone any reaction is directly carried out to the regeneration flue gas dust treatment system along with the regeneration flue gas, and part of it is recovered by the third-stage cyclone separator (referred to as "three-cyclone", before which the large particle catalyst >30um has been recovered by the first and second-stage cyclone separators, a total of three stages) and treated as waste. This is one of the reasons why the activity (about 90) of the three-stage cyclone dust agent (i.e. the dust agent recovered by the third-stage cyclone separator) is much higher than that of the system equilibrium catalyst (generally the activity is below 60).

[0057] Based on the above two reasons, the present invention finds that the feeding position of the fresh catalyst in the regeneration unit is changed from the fresh catalyst outlet position 401 of the traditional feed pipe to the fresh catalyst outlet position 402 of the feed pipe, so that the fresh catalyst is transported to a specific position near the regeneration catalyst collection tank in the regeneration unit, and combined with the automatic metering dosing function of the automatic feeder and the comprehensive effects of the flow stabilizing element to eliminate pulse interference and uniform constant dosing, the above problems can be solved, wherein:

[0058] Pulse type automatic feeder: As a means of automatic metering and supplementing the daily fresh catalyst of the device, it is widely used due to its advantages of high degree of automation, convenient operation, accurate timing and quantitative measurement, low failure rate, etc. However, due to its pulse and intermittent dosing method and the instantaneous change of the supporting conveying air volume, the injection of fresh catalyst at the fresh catalyst outlet position 402 of the feed pipe is too close to the collection tank of the regenerated catalyst circulation, which will cause the pulse type dosing conveying wind to be large and small periodically, which may affect the stable operation of the catalyst circulation of the reactor and regenerator; at the same time, due to the interval fresh catalyst addition mode, the amount of fresh catalyst replenished will frequently appear sometimes, sometimes not, sometimes large, and sometimes small in each dosing cycle, which will also cause periodic activity quality change interference in the regenerated circulating catalyst participating in the riser cracking reaction.

[0059] Flow stabilizer: The present invention utilizes a flow stabilizer to avoid the interference of the direct use of a pulse-type automatic feeder on the catalyst circulation of the reactor during feeding. In a preferred embodiment, the flow stabilizer includes a flow stabilization tank 005 and a fluidizing tank 006; the flow stabilization tank 005 is connected to the pulse-type automatic feeder 003 through a pipeline 0051, and an air inlet valve 0052 is provided on the pipeline, and the gas outlet is arranged at the top of the flow stabilization tank, and the fluidizing tank 006 includes a fresh catalyst inlet and a fresh catalyst outlet, and the fresh catalyst inlet is connected to the flow stabilization tank.

[0060] It can be understood that the pulse type automatic feeder 003 is only used for automatically metering and pressing out the fresh catalyst, and the pulse type automatic feeder is connected to the air intake pipe 0051 for transporting the catalyst;

[0061] The flow stabilization tank 005 is used to receive the fresh catalyst delivered by the pulse automatic feeder. It also has the functions of gas-solid separation and storage, as well as constant dosage addition.

[0062] Fluidizing tank 006 is connected to the bottom of the simmering tank. The bottom of the fluidizing tank is connected to a fluidizing air inlet pipeline to fluidize the solid catalyst. The fresh catalyst at the bottom of the simmering tank flows into the fluidizing tank. The gas discharged from the top of the simmering tank is connected to the feed pipe 004 and combined with the material discharged from the fluidizing tank to be charged into the regeneration unit.

[0063] In one embodiment, the bottom of the swirl pot includes a first gas inlet (see Figure 1 ), used to introduce loosening air to ensure that the fresh catalyst at the bottom of the stabilizing tank is in a dense phase loose fluidized state.

[0064] In another specific embodiment, the bottom of the fluidized tank includes a second gas inlet for introducing fluidizing air to ensure that the fresh catalyst in the fluidized tank is in a fluidized state. The fresh catalyst in the fluidized tank is fluidized and then sent to the regeneration unit for a normal, fixed amount, and continuous dosing mode.

[0065] In a specific embodiment, a regulating valve is provided on the pipeline 0051, and the regulating valve is used to adjust the size of the intake air volume. The control of the air volume of the pipeline is affected by the pressure of the simmering tank, so that the total air volume of fresh catalyst delivered to the regenerator can be effectively controlled to be constant, and the occurrence of pulse-like air volume changes can be avoided. Furthermore, a flow control valve 0053 is also provided between the simmering tank and the fluidizing tank to quantitatively control the fresh catalyst entering the fluidizing tank; further, the simmering tank is provided with a storage volume control meter 0054 and a pressure display and control meter 0055 to monitor and adjust the stability of the simmering tank pressure and the change of the constant addition amount.

[0066] In one specific embodiment, the volume ratio of the swirl tank to the fluidizing tank is 4-6.

[0067] It can be understood that the general regenerator unit includes a dilute phase section (catalyst dilute phase bed), a transition section (catalyst transition phase bed), and a dense phase section (catalyst dense phase bed). For example, the density range of the dense phase section is 300~800kg / m 3 The height of the dense phase section accounts for 50-85% of the total height of the regeneration unit shell; the height of the dilute phase section accounts for 15-45% of the total height of the regeneration unit shell; the height of the transition section accounts for 2-5% of the total height of the regeneration unit shell. For example, the density of the catalyst dense phase bed at the top is 300 kg / m 3 、350kg / m 3 , 400kg / m 3 , 450kg / m 3 , 500kg / m 3 , transition section density <300kg / m 3 .

[0068] In a specific embodiment, a regeneration first and second cyclone separator is arranged in the catalyst dilute phase bed of the regeneration unit, a regeneration third cyclone separator is connected to the top of the regeneration unit shell, a waste heat steam generator is connected to the top of the regeneration third cyclone separator through a pipeline, a flue gas dust removal (or containing denitrification and desulfurization functions) device is connected to the waste heat steam generator, and a regeneration fine powder collection tank is connected to the bottom of the regeneration third cyclone separator. The regeneration first and second cyclone separators are mainly used to recycle large-particle catalysts with a size of >30um, and the regeneration third cyclone separator is mainly used to recycle small-particle catalyst dust with a size of ≤30um.

[0069] In a specific embodiment, a main air distribution pipe 007 is provided at the lower part of the catalyst dense phase bed for introducing oxygen-containing gas into the regeneration unit.

[0070] The main air distribution pipe 007 is used to transport the main air to the bottom of the regeneration unit shell to evenly distribute the gas so that the main air can evenly contact the regenerated catalyst on the bed. This is beneficial to evenly burn and regenerate the regenerated catalyst to obtain a low carbon content and uniform regenerated catalyst, so as to improve the selectivity and activity required for the catalytic cracking reaction.

[0071] For example, the top of the catalyst dense phase bed is a circular cross section, which is a circle with a diameter of 2R; a branch pipe is arranged on the main air duct, and the gas enters the main pipe with a diameter of 0.2R~0.3R and then flows into 4 branch pipes with a diameter of 0.08R~0.12R. The branch pipes are arranged at equal intervals, and 8 branch pipes with a diameter of 0.04R~0.06R are arranged symmetrically and evenly on the left and right sides of the branch pipe, and finally sprayed out by nozzles arranged at equal intervals on the branch pipe, and the nozzles are alternately distributed at an angle of 45° downward. The entrance position of the regenerated catalyst collection tank is a circle with a diameter of 0.1R~0.5R.

[0072] On the other hand, there is a corrosive environment in the reactor and regenerator unit of the catalytic cracking unit. The high-temperature gas in the catalytic cracking unit is mainly the flue gas generated during the catalyst regeneration process. The O2, SO2, CO2 and water vapor in the flue gas are corrosive. When the temperature is lower than the flue gas dew point, the high-temperature flue gas contacts the metal wall to produce a high-concentration acid solution to form NO X -SO X -H2O corrosive environment, causing nitrate stress corrosion cracking of carbon steel. SO XThe main component is SO2. With the increase of excess oxygen content in the regeneration unit, the increase in dew point caused by the increase in SO3 content and the enhanced burning of CO combustion aid can increase the sensitivity of nitrate stress corrosion cracking. The high-temperature regeneration flue gas containing catalyst solid particles causes high-temperature flue gas corrosion, erosion and abrasion on the inner wall and component lining of the regenerator, causing the lining to wear and thin. When the flue gas penetrates between the lining and the metal wall and the wall temperature is lower than the flue gas dew point, the acidic solution formed by the reaction will form NO X -SO X -H2O corrosive environment can also cause nitrate stress corrosion cracking of carbon steel.

[0073] In addition, the parts with more serious high-temperature oxidation include overflow pipes, maintenance platforms and cyclone separator reinforcements, and the parts with more serious high-speed catalyst abrasion include regenerator distribution pipes (plates), cyclone separator ash hoppers and wing valves. In addition, under the conditions of regeneration flue gas, steel will produce oxidation and decarburization, which affects the mechanical strength of steel and reduces the fatigue limit and surface hardness of steel. The abrasion of catalysts is caused by the high-speed scouring of the equipment by catalyst solid particles and the corrosive medium. In recent years, due to the widespread use of new catalysts, their high-temperature strength has been significantly improved. At the same time, the increase in regeneration temperature and the acceleration of flow rate make the catalyst abrasion and erosion more severe. Moreover, the pipe body and nozzle parts made of some layered composite materials have weak material bonding due to the difference in expansion coefficients of different materials. The worn or broken pipe body and nozzle affect the uniform distribution of the medium in the conveying pipe and regenerator, and even affect the fluidization of the medium. Therefore, the materials in the regenerator that are in direct contact with the catalyst, withstand the corrosive environment, and are resistant to high temperatures also need to be improved.

[0074] In 2021, CN217149085U disclosed a large-hole distribution plate anti-vortex wear-resistant short tube for a heavy oil catalytic cracking regenerator. The wear-resistant short tube includes a nozzle and an outer sleeve. The outer sleeve is made of 304 stainless steel, and the nozzle is made of brittle high-alloy wear-resistant steel. However, under the regeneration flue gas conditions, steel will oxidize and decarburize, affecting the mechanical strength of steel and reducing the fatigue limit and surface hardness of steel.

[0075] In 2021, CN111094603B disclosed a nickel-based alloy with high corrosion resistance, but due to the use of a high content of Ni, Cr, and Mo alloy elements, the production cost is high, and the operating temperature is not higher than 625°C, which does not meet the high-temperature use conditions in the regenerator.

[0076] In 2023, CN116555604A disclosed a Ni-Cr-Fe alloy and a method for improving the corrosion resistance of its plate. Ni-Cr-Fe nickel-based alloys are widely used in petrochemical pipelines and chemical reactors due to their excellent corrosion resistance. However, due to the use of high content of Ni and Cr alloy elements, the production cost is relatively high.

[0077] In view of the above problems, in a preferred embodiment, the portion of the feed pipe extending to the interior of the housing of the regeneration unit and / or the main air distribution pipe comprises: a substrate and a coating disposed on the surface of the substrate;

[0078] The substrate meets the following conditions:

[0079] At room temperature, the V-notch impact toughness of the matrix is ​​5.0~6.0J / cm 2 , 750℃ tensile properties meet the following requirements: tensile strength ≥ 300MPa, yield strength ≥ 200MPa, elongation ≥ 30%;

[0080] The coating meets the following conditions:

[0081] The hardness of the coating is ≥50HRC, and the bonding strength between the coating and the substrate is ≥50MPa.

[0082] Furthermore, the material of the matrix is ​​an iron alloy, in which M 23 C6 type carbide; the coating comprises WC, Cr3C2, Co and Mo.

[0083] Furthermore, the ferroalloy comprises, by mass percentage, Cr: 15-17%, W: 9-10%, Co: 6-8%, Mo: 3-5%, Ta+Nb: 2-3%, C: 1-2% and the remainder Fe; and the ferroalloy does not contain Ni;

[0084] And / or, in the coating, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2-3:1;

[0085] And / or, in the coating, the average particle sizes of WC and Cr3C2 are each independently 50-150 nm, and the average particle sizes of Co and Mo are each independently 0.5-1.0 μm.

[0086] In the matrix, C has interstitial solid solution strengthening effect and can form M 23C6 carbide, carbide is precipitated preferentially at the grain boundary, which can hinder grain boundary sliding and crack propagation to improve creep strength and creep plasticity; Cr can improve the oxidation resistance and corrosion resistance of the alloy under high temperature conditions, but the Cr content should not be too high, otherwise it will reduce the structural stability of the matrix; Mo and W are important solid solution strengthening elements, which can significantly improve the high temperature strength and service life of the alloy and improve the structural stability; excessive Mo and W will reduce the solid solution strengthening effect. Excessive Mo is prone to pitting, and excessive W is prone to segregation; Co is a solid solution strengthening element that can reduce the stacking fault energy of the alloy and improve high temperature strength and plasticity. Co also has excellent corrosion resistance, heat resistance and oxidation resistance. Co is used to form hard metal compounds with Cr in the matrix, making it dispersed in the alloy to play a role in dispersion strengthening. Ta and Nb are important precipitation phase forming elements in heat-resistant alloys. They generate nano-scale carbonitrides, which help to have excellent thermal stability at high temperatures and can effectively pin dislocations. Fe achieves the hot working properties required by the alloy at a lower cost. Too high Fe content will reduce the structural stability and high-temperature strength of the alloy. In the coating, WC and Cr3C2 have high hardness and can improve wear resistance, while Co and Mo can form an alloy, which is equivalent to a binder.

[0087] It should be noted that the present invention does not specifically limit the method for manufacturing the iron alloy substrate, and for example, the iron alloy substrate can be prepared by a method comprising the following steps:

[0088] Step 1: According to the target ferroalloy composition, raw materials other than Co and C are prepared, and an iron-based alloy solution A is prepared by a vacuum smelting method; the iron-based alloy solution A is prepared into alloy powder A by a vacuum atomization powder making technology, and alloy powders with a size less than 300 mesh are screened out, i.e., iron-based alloy powder A; the smelting temperature is 1500° C.-1800° C., and the smelting time is 4-6 minutes;

[0089] Step 2: The iron-based alloy powder A obtained in step 1 is mixed with powders containing Co and C, and a mixed powder is obtained by ball milling, wherein the mixed powder meets the target iron alloy composition;

[0090] Step 3: The mixed powder obtained in step 2 is sintered by hot isostatic pressing at a temperature of 1350-1400°C for 2-3 hours at a pressure of 150-200 MPa;

[0091] Step 4: heat-treat the product obtained by sintering in step 3, keep it at 1000-1200℃ for 10-40 minutes, and then quench and temper it; in the iron alloy matrix, M 23 C6 carbide is an endogenous reinforcement phase.

[0092] The present invention does not specifically limit the method for preparing the coating, and for example, the coating can be prepared by a method comprising the following steps:

[0093] Add WC powder, Co, Mo, and Cr3C2 powder into a ball mill in proportion and mix them by ball milling. The ball milling time is 24 to 48 hours to obtain a uniformly mixed coating powder. The rotation speed of the ball mill is 60 to 65 r / min, and the ball-to-material ratio is 3 to 5:1.

[0094] In a preferred embodiment, the thickness of the coating is 50-150 μm. For example, the uniformly mixed coating powder is coated on the surface of the ferroalloy substrate, and the coating and the ferroalloy substrate can be combined by flame spraying, laser cladding and other processes.

[0095] The feed pipe made of the above specific materials has a surface hardness of 50-55HRC and a weight loss of about (4-5)×10 after oxidation at 750℃ / 200h. -3 mg / cm 2 ·h, in 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.07~0.09mm / a.

[0096] It should be noted that other components in the regeneration unit may also use this material composed of a specific matrix and a surface coating, including but not limited to the main air distribution pipe, cyclone separator, etc.

[0097] As for the properties and functions of the fresh catalyst, the present invention does not specifically limit them. For example, it can be an amorphous silica-alumina catalyst or a molecular sieve catalyst, such as SAPO-17, SAPO-34, SAPO-44, ALPO-18, ALPO-31, ALPO-34 alone or any mixture thereof; the crushing strength of the fresh catalyst is 40-50N, and the apparent bulk density is 0.7-1.0g / cm 3 , activity 70~90, specific surface area 250~300m 2 / g, pore volume is 0.1~0.25cm 3 / g, and the average pore size is 5~25nm.

[0098] In a second aspect, the present invention provides a method for feeding using the above-mentioned catalytic cracking unit feeding system, comprising the following steps:

[0099] The fresh catalyst is automatically pressed out by a pulse automatic feeder and then transported to the flow stabilizing member by a transport gas, so that the fresh catalyst and the transport gas are input from the fresh catalyst outlet of the feed pipe to a position close to the regenerated catalyst collecting tank in the regeneration unit, the fresh catalyst and the regenerated catalyst are mixed, and the mixed mixture is continuously transported to the reaction cracking unit through a dedicated catalyst circulation pipeline.

[0100] In a preferred embodiment, the single feeding weight of the pulse automatic feeder is 1-150 kg, and the interval time is 5 min-1 h; when transporting to the flow stabilizing member, the feeding speed of the fresh catalyst is 50-500 kg / h.

[0101] In a preferred embodiment, the top pressure of the regeneration unit is 0.2-0.3 MPa, the catalyst dilute bed temperature of the regeneration unit is 675-685°C, and the catalyst dense bed temperature of the regeneration unit is 660-670°C.

[0102] For example, the volume percentage of oxygen in the mixed gas entering the regeneration unit from the main air distribution pipe is usually 20-40%, the temperature of the charring reaction in the regeneration unit is 660-685°C, and the main air flow rate is 5W-7Wm 3 / h. The diameter of the regeneration unit is φ5000 mm; the diameter of the main pipe of the regenerated catalyst feed pipe is φ740 mm, and the length in the regeneration unit is 4000 mm. An air intake pipe 0051 is set with a diameter of φ200 mm and a conveying air volume of 6500 standard cubic meters / hour.

[0103] Illustratively, the gas linear velocity of the dense phase catalyst bed of a specific embodiment of the present invention is 0.7 m / s, and the main air volume is 44,000 standard cubic meters / hour; the top design pressure of the general regeneration unit is 0.2MPa~0.4MPa, and the top pressure of the regeneration unit operation of a specific embodiment of the present invention is 0.2~0.3MPa, the dilute phase catalyst bed temperature of the regeneration unit is 675~685°C, and the dense phase catalyst bed temperature of the regeneration unit is 660~670°C.

[0104] The present invention is further described below in conjunction with examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection claimed by the present invention.

[0105] The catalyst used in the following experiments is a molecular sieve catalyst.

[0106] Research 1: The influence of dosing position on fresh catalyst loss and correction ideas

[0107] One of the ideas for correction is that the fresh catalyst is added to the dense phase bed under high temperature conditions in the regenerator (by Figure 3The fresh catalyst is added at the outlet position 401 of the traditional feed pipe). During the transportation process, there are serious thermal collapse (including wear and tear) and breakage phenomena, as well as fluidization impact of the bubbling bed carrying upward (except the regenerated catalyst collection tank area). A large amount of crushed fresh catalyst fine powder is discharged from the chimney along with the regenerated flue gas (part of the waste agent is recovered by the three-cyclone), causing the problem of loss during the addition of fresh catalyst. Therefore, whether this process can be avoided or shortened is one of the guiding ideas for effectively solving the loss problem.

[0108] The second positional influence and correction idea is that during the charring and fluidization process of the entire dense phase bed of the regenerator, a main air distribution pipe and a large number of nozzles are arranged at the bottom of the regenerator. Under the action of air and charring, a violent upward bubbling bed fluidization phenomenon is formed. However, the catalyst after regeneration also needs to be continuously transported to the cracking reactor to participate in the reaction. Therefore, in the area 403 at the entrance of the external transport regenerated catalyst collection tank, the process design is not equipped with a main air injection nozzle. Therefore, within this area, the catalyst particles after regeneration appear to flow countercurrently downward from the top of the dense phase bed to ensure that the catalyst after regeneration can be continuously circulated and transported outward. Therefore, if fresh catalyst is added to this area, and a large amount of countercurrent downward circulating regenerated catalyst is used above to entrain and take away all the fresh catalyst added (including possible fine powder), the effect of no loss when the fresh catalyst is added can be achieved.

[0109] The third idea of ​​position influence and correction is that since the catalytic cracking production unit needs to continuously and in large quantities carry out the catalyst circulation between the reactor and the regenerator (hereinafter referred to as the two devices) to meet the needs of reaction cracking, catalyst regeneration and heat balance transfer, the stability of the working condition in the area 403 of the entrance position of the regenerated catalyst collection tank is extremely sensitive and important. Therefore, it is the key to the success of the implementation of this plan to test and explore the appropriate position of the feed point without causing adverse effects on the catalyst circulation of the two devices. Because, if the feed point is too far away, it will not affect the normal operation of the fluidized circulation of the two devices (such as Figure 3 The fresh catalyst outlet position 401 of the traditional feed pipe in the conventional feed pipe is too close, but it affects the effect of reducing the loss of fresh catalyst, so the effect is also worse as the point is far away; if the addition point is too close, although it is extremely beneficial to reduce the loss of fresh catalyst, it affects the normal circulation of the catalyst in the two-device system and even causes interruption, so its impact is also increased by the closeness of the point. Therefore, the experiment should explore the appropriate position of the feeding point, in principle, from far to near, gradually approaching the regenerated catalyst collection tank inlet position 403 area, and conduct effect comparison exploration.

[0110] The fourth idea of ​​position influence and correction is to maximize the proximity of the feeding point to the regenerated catalyst collection tank inlet position 403 area. This solution also requires that this kind of external fresh catalyst must be added in a balanced, stable and non-interference manner. However, due to the fact that the original automatic feeding facility has a phenomenon of sometimes more, sometimes less, sometimes no addition amount, and sometimes large and sometimes small delivery air volume during the feeding process, a pulsed interference state is formed on the regenerator feeding point. Due to concerns about interference with the stable circulation of the catalysts in the two devices, this is also why the conventional design often keeps the feeding port of the fresh catalyst away from the sensitive area of ​​the regenerated catalyst collection tank inlet position 403. Therefore, in order to avoid this interference factor, a flow stabilizer is designed in this embodiment (see Figure 1 ) is used to minimize the impact of external feed on the sensitive area by using a uniform wind speed and balanced dosage, while maximally locating the feed point close to the regenerated catalyst collection tank inlet position 403.

[0111] According to the above-mentioned influence of the adding position on the fresh catalyst loss and the guiding principle of the correction idea, the following Example 1 is carried out

[0112] Example 1

[0113] This example provides a catalytic cracking unit feeding system, and the pipeline material involved in this example is selected from the nickel-based alloy of the NCOLOY800 series; Figure 1 and Figure 2 The catalytic cracking unit feeding system includes a regeneration unit and a fresh catalyst feeding unit; the regeneration unit includes a shell 001 containing a catalyst dense phase bed 0011 and a catalyst dilute phase bed 0012; a regenerated catalyst collecting tank 002 is provided at the bottom of the shell; the fresh catalyst feeding unit includes: a pulse automatic feeder 003 and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, and the gas outlet and the fresh catalyst outlet are connected to the inside of the regeneration unit through a feed pipe 004;

[0114] A regeneration first and second stage cyclone separator is arranged in the catalyst dilute phase bed layer, a regeneration third stage cyclone separator is connected to the top of the regeneration unit shell, a waste heat steam generator is connected to the top of the regeneration third stage cyclone separator through a pipeline, a flue gas dust removal (or containing denitrification and desulfurization functions) device is connected to the waste heat steam generator, a regeneration fine powder collection tank is connected to the bottom of the regeneration third stage cyclone separator, the regeneration first and second stage cyclone separators are mainly used to recycle large particle catalysts with a size of >30um, and the regeneration third stage cyclone separator is mainly used to recycle small particle catalyst dust with a size of ≤30um.

[0115] The fresh catalyst feeding unit comprises: a pulse automatic feeder 003 and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, the gas outlet and the fresh catalyst outlet are connected to the inside of the regeneration unit through a feed pipe 004, and the fresh catalyst outlet position 402 of the feed pipe satisfies the following relationship and design value (see attached for details): Figure 2 , including the coordinate position of the dosing port): m=0.1R, h1=0.25H.

[0116] Among them, the top of the catalyst dense phase bed is a circular cross-section, R is the radius of the circle; m is the horizontal straight line distance from the fresh catalyst outlet to the perpendicular line of the center of the circle at the inlet of the regenerated catalyst collecting tank; H is the vertical distance between the circular cross-section and the plane where the inlet of the regenerated catalyst collecting tank is located; h1 is the vertical distance from the plane where the inlet of the regenerated catalyst collecting tank is located to the plane where the fresh catalyst outlet is located.

[0117] The flow stabilizing device includes a flow stabilizing tank 005 and a fluidizing tank 006; the flow stabilizing tank 005 is connected to the pulse automatic feeder 003 through a pipeline 0051, and an air inlet valve 0052 is provided on the pipeline. The gas outlet is arranged at the top of the flow stabilizing tank, and the fluidizing tank 006 includes a fresh catalyst inlet and a fresh catalyst outlet, and the fresh catalyst inlet is connected to the flow stabilizing tank.

[0118] In order to further explore and verify the influence of different feeding point positions on the fresh catalyst loss, the following examples were conducted:

[0119] Embodiment 2-5

[0120] The feeding system of the catalytic cracking unit is basically the same as that of Example 1, with the only difference being that the position of the fresh catalyst outlet is gradually moved. The moving position and the corresponding effects and descriptions are detailed in Table 2.

[0121] Comparative Example 1

[0122] The catalytic cracking unit feeding system is basically the same as that of Example 1, except that the fresh catalyst outlet position 402 of the feed pipe is restored to the fresh catalyst outlet position 401 of the conventional feed pipe, see Figure 3-4 As shown, the straight line where the fresh catalyst outlet position 401 of the conventional feed pipe and the center of the circle are located, and the straight line where the inlet position 403 of the regenerated catalyst collection tank and the center of the circle are located form Angle, and the fresh catalyst outlet position 401 of the traditional feed pipe satisfies: m=1.0R, h1=0.2H.

[0123] Test example:

[0124] The catalytic cracking unit feeding system of the embodiment and the comparative example is used to feed the material, comprising the following steps:

[0125] The fresh catalyst is automatically pressed out by a pulse automatic feeder, and then transported to a flow stabilizing member through a conveying gas, so that the fresh catalyst and the conveying gas are stably input from the fresh catalyst outlet of the feed pipe to a specific position near the collecting tank in the regeneration unit, and the fresh catalyst and the regenerated catalyst are fully mixed to improve the activity quality required by the catalyst after uniform mixing. The mixed mixture is continuously transported to the reaction cracking unit through a dedicated catalyst circulation pipeline, and contacts and reacts with the mixed raw materials to be reacted at a certain oil-to-agent ratio, so as to obtain the reaction required for the production of the catalytic cracking device and all the target products; the single feeding weight of the pulse automatic feeder is 100 kg, and the interval time is 30 minutes.

[0126] When conveying to the flow stabilizer, the feeding rate of fresh catalyst is 250Kg / h. The top pressure of the regeneration unit is 0.25MPa, the dilute phase catalyst bed temperature of the regeneration unit is 680℃, and the dense phase catalyst bed temperature is 665℃.

[0127] Among them, the experimental data comparison and effects of charging the catalytic cracking device charging system of Example 1 and Comparative Example 1 are shown in Table 1, and the experimental data comparison and effects of charging the catalytic cracking device charging system of Examples 1-5 and Comparative Example 1 are shown in Table 2.

[0128] Table 1: Comparison of experimental data and effects of Example 1 and Comparative Example 1

[0129]

[0130] From the test results in Table 1, we can see that:

[0131] The data of comparative example 1 (before transformation) show that: in the test of three batches using the catalytic cracking unit feeding system (the time of one batch is uniformly 30 days, the same below, recorded as before transformation), the sum of the excess dosage discharged from the regeneration unit is 330 tons, and the sum of the fresh catalyst supplementary addition is 780 tons; the calculated discharge / addition ratio of the three batches before transformation is 42.4%;

[0132] The data of Example 1 (after transformation) show that: in the three batches of tests conducted using the catalytic cracking unit feeding system (recorded as after transformation), the sum of the excess dosage discharged from the regeneration unit was 465 tons; the sum of the fresh catalyst supplementary addition was 780 tons; and the calculated discharge / addition ratio of the three batches after transformation was 59.6%;

[0133] Comparative analysis of the effects of the above two sets of data: "The ratio of discharge to addition increased" (see column 3, also known as the reduction of running loss ratio), from 42.4% before the transformation to 59.6% after the transformation, a net increase of 17.2%. If the average monthly (30 days, the same below) addition of 260 tons (780 / 3=260) of fresh catalyst is still calculated based on the transformation, 44.7 tons of regenerated catalyst can be discharged from the regeneration unit every month (260×17.2%=44.7 tons, because the process requires regular discharge of the spent catalyst to ensure the quality of the system regenerated catalyst, see columns 5 and 6)

[0134] Preliminary conclusion: The comparison of the above data shows that the transformation of Example 1 has achieved obvious results, that is, with other process production conditions basically unchanged, only the way of adding fresh catalyst is changed, which can achieve 44.7 tons of regenerated catalyst unloaded from the regeneration unit per month, and the extra catalyst in the system is precisely the good effect produced by this transformation, that is, the amount of fine powder generated by thermal collapse of the original fresh catalyst added in an equal amount, which is directly lost from the regenerated flue gas when the fresh catalyst is added to the regeneration unit, is significantly reduced.

[0135] The data on the reduction of the amount of fine powder discharged from the three cyclones shows that the total amount of fine powder discharged from the three cyclones in the three batches before the transformation was 33 tons; the total amount of fine powder discharged from the three cyclones in the three batches after the transformation was 12 tons; "The reduction of fine powder recovery agent from the three cyclones" (see column 4) shows that the monthly discharge amount has been greatly reduced from 11 tons to 4 tons after the transformation, indicating that the amount of fine powder directly lost from the regenerated flue gas has also been reduced synchronously after the transformation, which also proves the reduction in the degree of crushing when fresh catalyst is added. (Note: The fine powder agent is the part of the regenerated flue gas dust that can be recovered by the third-stage cyclone, except for the part that is too fine and cannot be recovered, so the increase in the amount of catalyst directly discharged from the regeneration unit is much greater than the reduction in the fine powder recovery agent from the three cyclones, and the agent is analyzed as a highly active agent).

[0136] The data on catalyst activity and specific surface area quality improvement show that the sum of the regenerated catalyst activities in the three batches before the transformation was 135; the sum of the regenerated catalyst activities in the three batches after the transformation was 180; "The quality of the balanced catalyst in the system has been improved" (see columns 5 and 6). The main catalyst quality indicators have improved significantly after the transformation, with the monthly average activity increasing from 45.0 to 60.0; similarly, the calculated monthly average specific surface area of ​​the regenerated catalyst increased from 65 to 88, reaching a maximum of 89. This is conducive to reducing the amount of fresh catalyst added to the catalytic cracking unit under the same system regenerated catalyst cracking quality requirements, so as to achieve the goal of reducing costs and increasing efficiency.

[0137] Table 2: Comparison of experimental data and effects of Examples 1-5 and Comparative Example 1

[0138]

[0139] From the test results in Table 2 and the comparison between the data in Table 2 and the data in Table 1, we can see that:

[0140] For the test conducted using the catalytic cracking unit feeding system of Example 2, the discharge / addition ratio was 53.8%; compared with the discharge / addition ratio of 59.6% at the specific preferred position after the modification of Example 1, there was a certain degree of decrease, and the activity of the regenerated catalyst and the specific surface area of ​​the regenerated catalyst also decreased accordingly, and the fine powder discharged by the three-rotor increased, but the overall effect was still better than the corresponding data before the modification of Comparative Example 1;

[0141] For the test conducted using the catalytic cracking unit feeding system of Example 3, the discharge / addition ratio was 48.1%; compared with the discharge / addition ratio of 59.6% at the specific preferred position after the modification of Example 1, it decreased to a certain extent, and the activity of the regenerated catalyst and the specific surface area of ​​the regenerated catalyst decreased, and the fine powder discharged by the three-rotor increased, but the overall effect was better than the corresponding data before the modification of Comparative Example 1;

[0142] For the test conducted using the catalytic cracking unit feeding system of Example 4, the discharge / addition ratio was 46.1%; compared with the discharge / addition ratio of 59.6% at the specific preferred position after the modification of Example 1, it decreased to a certain extent, and the activity of the regenerated catalyst and the specific surface area of ​​the regenerated catalyst decreased again, and the fine powder discharged by the three-rotor increased, but the overall effect was better than the corresponding data before the modification of Comparative Example 1;

[0143] For the test conducted using the catalytic cracking unit feeding system of Example 5, the discharge / addition ratio was 44.2%; compared with the discharge / addition ratio of 59.6% at the specific preferred position after the modification in Example 1, it was further reduced, and the activity of the regenerated catalyst and the specific surface area of ​​the regenerated catalyst were further reduced. The fine powder discharged by the three-rotor increased, but the overall effect was still better than the corresponding data before the modification in Comparative Example 1.

[0144] Preliminary conclusion: Based on the analysis data of all experiments (discharge / addition ratio, three-rotation fine powder recovery, catalyst main mass, etc.), the closer the fresh catalyst addition point is to the entrance of the regenerated catalyst collection tank, the better the effect, and vice versa. Among them, the position of Example 1 is the best. At the same time, the experimental data also verifies that the feed stabilizing flow device has achieved a relatively ideal effect in reducing the interference caused by the fresh catalyst when it is added to the regenerator.

[0145] Research 2: The influence of different pipeline materials on their related mechanical properties, wear resistance, etc.

[0146] In the following embodiments: hardness is measured according to GB / T 230.1-2018 "Rockwell hardness test for metallic materials - Part 1: Test method"; weight loss is measured according to aviation industry standard HB5258-2000 "Test method for determination of oxidation resistance of steel and high temperature alloys"; corrosion resistance rate is measured according to GB10124-1988 "Laboratory uniform corrosion full immersion test method for metallic materials"; impact toughness is measured according to GB / T 229-2007 "Charpy pendulum impact test method for metallic materials"; 750°C tensile properties are measured according to GB / T 228.2-2015 "Tensile test for metallic materials - Part 2: High temperature test method".

[0147] Example 6

[0148] The catalytic cracking unit feeding system of Example 1 was used, and only the material of the feed pipe was changed: the pipe material of the feed pipe consisted of a substrate and a coating on the substrate surface, wherein the substrate was an iron alloy, and the iron alloy contained uniformly dispersed M 23 C6 type carbide, the iron alloy is Cr 15%, W 9%, Co 6%, Mo 3%, Ta+Nb 2%, C1%, and the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 6.0J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 300MPa, yield strength is 200MPa, and elongation is 38%.

[0149] A coating with a thickness of 50 μm is deposited on the surface of the substrate; the coating materials include: WC, Cr3C2, Co, Mo, specifically WC, Cr3C2 doped Co-Mo alloy, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2:1; the average particle size of WC and Cr3C2 powders is 150 nm, and the average particle size of Co and Mo powders is 1.0 μm.

[0150] After testing: the surface hardness of the pipeline material is 50HRC, and the weight loss after oxidation at 750℃ / 200h is about 5.0×10 -3 mg / cm 2 ·h; in 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.09mm / a; the bonding strength between the coating and the substrate is ≥50MPa.

[0151] Example 7

[0152] Same as Example 6, except that: the pipe material of the feed pipe is composed of a substrate and a coating on the substrate surface, wherein the substrate is an iron alloy, and the iron alloy has uniformly dispersed M 23C6 type carbide, the iron alloy is Cr16%, W 9.5%, Co 7%, Mo 4%, Ta+Nb 2.5%, C 1.5%, and the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 5J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 340MPa, yield strength is 220MPa, and elongation is 32%.

[0153] A coating with a thickness of 100 μm is deposited on the surface of the substrate. The coating materials include: WC, Cr3C2, Co, and Mo, specifically, Co-Mo alloy doped with WC and Cr3C2, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2.5:1; the average particle size of WC and Cr3C2 powders is 100 nm, and the average particle size of Co and Mo powders is 0.7 μm.

[0154] After testing, the surface hardness of the pipeline material is 55HRC, and the weight loss after oxidation at 750℃ / 200h is about 4.0×10 -3 mg / cm 2 ·h; in 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.07mm / a; the bonding strength between the coating and the substrate is ≥50MPa.

[0155] Example 8

[0156] Same as Example 6, except that: the pipe material of the feed pipe is composed of a substrate and a coating on the substrate surface, wherein the substrate is an iron alloy, and the iron alloy has uniformly dispersed M 23 C6 type carbide, iron alloy by mass percentage is Cr17%, W 10%, Co 8%, Mo 5%, Ta + Nb 3%, C 2%, the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 5.5J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 320MPa, yield strength is 210MPa, and elongation is 35%.

[0157] A coating with a thickness of 150 μm is deposited on the substrate surface. The coating materials include: WC, Cr3C2, Co, Mo, specifically WC, Cr3C2 doped Co-Mo alloy, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 3:1; the average particle size of WC and Cr3C2 powder is 50 nm, and the average particle size of Co and Mo powder is 0.5 μm.

[0158] After testing, the surface hardness of the pipeline material is 52HRC, and the weight loss after oxidation at 750℃ / 200h is about 4.5×10 -3 mg / cm2 ·h; in 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.08mm / a; the bonding strength between the coating and the substrate is ≥50MPa.

[0159] Example 9

[0160] The same as Example 6, except that: the pipe material of the feed pipe is composed of a substrate and a coating on the substrate surface, wherein the substrate is an iron alloy, and the iron alloy has uniformly dispersed M 23 C6 type carbide, the iron alloy is Cr10%, W 7%, Co 3%, Mo 5%, Ta+Nb 1%, C 0.1%, and the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 3.0J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 250MPa, yield strength is 170MPa, and elongation is 28%.

[0161] A coating with a thickness of 30 μm is deposited on the surface of the substrate. The coating materials include: WC, Cr3C2, Co, and Mo, specifically, Co-Mo alloy doped with WC and Cr3C2, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2:1; the average particle size of WC and Cr3C2 powder is 300 nm, and the average particle size of Co and Mo powder is 1.0 μm.

[0162] After testing, the surface hardness of the pipeline material is 33HRC, and the weight loss after oxidation at 750℃ / 200h is about 8.0×10 -3 mg / cm 2 ·h; In the 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.15mm / a.

[0163] Example 10

[0164] Same as Example 6, except that: the pipe material of the feed pipe is composed of a substrate and a coating on the substrate surface, wherein the substrate is an iron alloy, and the iron alloy has uniformly dispersed M 23 C6 type carbide, the iron alloy is Cr16%, W 5%, Co 4%, Mo 7%, Ta+Nb 1.5%, C 1.0%, and the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 3.5J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 260MPa, yield strength is 180MPa, and elongation is 26%.

[0165] A coating with a thickness of 100 μm is deposited on the surface of the substrate. The coating materials include: WC, Cr3C2, Co, Mo, specifically WC, Cr3C2 doped Co-Mo alloy, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 1:2; the average particle size of WC and Cr3C2 powder is 150 nm, and the average particle size of Co and Mo powder is 1.0 μm.

[0166] The test shows that the surface hardness of the pipeline material is 40HRC, and the weight loss after oxidation at 750℃ / 200h is about 7.1×10 -3 mg / cm 2 ·h; In the 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.11mm / a.

[0167] Embodiment 11

[0168] Same as Example 6, except that: the pipe material of the feed pipe is composed of a substrate and a coating on the substrate surface, wherein the substrate is an iron alloy, and the iron alloy has uniformly dispersed M 23 C6 type carbide, iron alloy by mass percentage is Cr17%, Ni 10%, Co 2%, Mo 5%, Ta 3%, C 2%, the rest is Fe. The V-notch impact toughness of the iron alloy at room temperature is 5.2J / cm 2 ; The tensile properties at 750℃ meet the following requirements: tensile strength is 280MPa, yield strength is 200MPa, and elongation is 29%.

[0169] A coating with a thickness of 50 μm is deposited on the substrate surface. The coating materials include: WC, Cr3C2, Co, Mo, specifically WC-doped Co-Mo alloy, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2:1; the average particle size of WC powder is 150 nm, and the average particle size of Co and Mo powder is 0.5 μm.

[0170] After testing, the surface hardness of the pipeline material is 42HRC, and the weight loss after oxidation at 750℃ / 200h is about 6.3×10 -3 mg / cm 2 ·h; In the 5% nitric acid solution at 100℃, the corrosion rate of the immersion corrosion test is 0.10mm / a.

[0171] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A catalytic cracking unit feeding system, characterized in that: include: A regeneration unit and a fresh catalyst feeding unit; the regeneration unit comprises a shell containing a catalyst dense phase bed and a catalyst dilute phase bed; A regenerated catalyst collecting tank is provided at the bottom of the shell; The fresh catalyst feeding unit comprises: a pulse automatic feeder and a flow stabilizer connected along the fresh catalyst feeding direction, the flow stabilizer is provided with a gas outlet and a fresh catalyst outlet, the gas outlet and the fresh catalyst outlet are connected through a feed pipe and the inside of the regeneration unit, and the fresh catalyst outlet of the feed pipe satisfies the following formulas 1 to 2: 0≤m≤0.5R Formula 1, 0.1H≤h1≤0.6H Formula 2; Among them, the top of the catalyst dense phase bed is a circular cross-section, R is the radius of the circular cross-section; m is the horizontal straight line distance from the fresh catalyst outlet of the feed pipe to the perpendicular line of the center of the circle at the entrance of the regenerated catalyst collecting tank; H is the vertical distance between the circular cross-section and the plane where the entrance of the regenerated catalyst collecting tank is located; h1 is the vertical distance from the plane where the entrance of the regenerated catalyst collecting tank is located to the plane where the fresh catalyst outlet of the feed pipe is located.

2. The catalytic cracking unit feeding system according to claim 1, characterized in that: The m satisfies: 0.1R≤m≤0.4R, and the h1 satisfies: 0.25H≤h1≤0.5H.

3. The catalytic cracking unit feeding system according to claim 1, characterized in that: The flow stabilizing element includes a swirl pot and a fluidizing pot; the swirl pot is connected to the pulse automatic feeder through a pipeline, an air inlet valve is provided on the pipeline, the gas outlet is arranged on the top of the swirl pot, the fluidizing pot includes a fresh catalyst inlet and the fresh catalyst outlet, and the fresh catalyst inlet is connected to the swirl pot; And / or, a main air distribution pipe is provided at the lower part of the catalyst dense phase bed for introducing oxygen-containing gas into the regeneration unit.

4. The catalytic cracking unit feeding system according to claim 3, characterized in that: The portion of the feed pipe extending to the interior of the housing of the regeneration unit and / or the main air distribution pipe comprises: a substrate and a coating arranged on the surface of the substrate; The substrate meets the following conditions: At room temperature, the V-notch impact toughness of the matrix is ​​5.0~6.0J / cm 2 , 750℃ tensile properties meet the following requirements: tensile strength ≥ 300MPa, yield strength ≥ 200MPa, elongation ≥ 30%; The coating meets the following conditions: The hardness of the coating is ≥50HRC, and the bonding strength between the coating and the substrate is ≥50MPa.

5. The catalytic cracking unit feeding system according to claim 4, characterized in that: The material of the matrix is ​​an iron alloy, in which M 23 C6 type carbide; the coating comprises WC, Cr3C2, Co and Mo.

6. The catalytic cracking unit feeding system according to claim 5, characterized in that: The ferroalloy comprises, by mass percentage, Cr: 15-17%, W: 9-10%, Co: 6-8%, Mo: 3-5%, Ta+Nb: 2-3%, C: 1-2% and the remainder Fe; and the ferroalloy does not contain Ni; And / or, in the coating, the total mass of WC and Cr3C2 is m1, the total mass of Co and Mo is m2, and the ratio of m1 to m2 is 2-3:1; And / or, in the coating, the average particle sizes of WC and Cr3C2 are each independently 50-150 nm, and the average particle sizes of Co and Mo are each independently 0.5-1.0 μm.

7. The catalytic cracking unit feeding system according to claim 6, characterized in that: The thickness of the coating is 50-150 μm.

8. A method for feeding using the catalytic cracking unit feeding system according to any one of claims 1 to 7, characterized in that: The following steps are involved: The fresh catalyst is automatically pressed out by a pulse automatic feeder and then transported to the flow stabilizing member by a transport gas, so that the fresh catalyst and the transport gas are input from the fresh catalyst outlet of the feed pipe to a position close to the regenerated catalyst collecting tank in the regeneration unit, the fresh catalyst and the regenerated catalyst are mixed, and the mixed mixture is continuously transported to the reaction cracking unit through a dedicated catalyst circulation pipeline.

9. The method according to claim 8, characterized in that The single feeding weight of the pulse automatic feeder is 1-150 kg, and the interval time is 5 min-1 h; when conveying to the flow stabilizing member, the feeding speed of the fresh catalyst is 50-500 kg / h.

10. The method according to claim 8, characterized in that The top pressure of the regeneration unit is 0.2-0.3 MPa, the catalyst dilute phase bed temperature of the regeneration unit is 675-685°C, and the catalyst dense phase bed temperature of the regeneration unit is 660-670°C.

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