Petroleum catalytic cracking system

Abstract

The present invention discloses a petroleum catalytic cracking system, and relates to the technical field of petroleum hydrocarbon catalytic cracking, the petroleum catalytic cracking system comprises: a riser unit used as a raw oil reactor; an inlet of the fractionation unit is communicated with an outlet of the riser unit; the oil-gas separator is communicated with an outlet of the fractionation unit; an inlet of the compression unit is communicated with an oil-gas outlet of the oil-gas separator; an inlet of the gas-liquid separator is communicated with an outlet of the compression unit, the gas-liquid separator is used for separating condensed oil and rich gas from the oil gas compressed by the compression unit, and the rich gas comprises C3 components and C4 components; the follow-up treatment unit is communicated with a gas outlet of the gas-liquid separator and is used for treating the rich gas to obtain dry gas and outputting the dry gas; a mixing unit, etc. The invention can overcome the defects of high energy consumption of an aerostatic press, large load of an absorption stabilizing system, low absorption effect, high content of C3 in dry gas and waste of components above C3 caused by medium lifting of the pre-lifter of the existing riser reactor.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum hydrocarbon catalytic cracking, and in particular to a petroleum catalytic cracking system. Background Art

[0002] Catalytic cracking technology is a technology commonly used in the petrochemical refining industry. A large amount of heavy residual oil (accounting for more than 60% of the raw oil) produced during the oil refining process can be converted into gasoline, diesel and petroleum gas that are in great demand in the national economy through this technology.

[0003] At present, the riser reactor in the petroleum catalytic cracking system generally uses dry gas or steam as the pre-lift medium. In the patent with application number CN202120595479.3, it is proposed to set the pre-lift gas feed pipe with a dry gas feed pipe and a steam feed pipe. The dry gas feed pipe is tilted and forms an acute angle with the steam feed pipe. The steam feed pipe and the dry gas feed pipe are controlled by a proportional controller. By setting a pre-lift gas feed pipe, a dry gas feed pipe and a steam feed pipe, a predetermined proportion of dry gas and steam are mixed to form a pre-lift gas and pass it into the riser reactor, so as to avoid catalyst cracking, improve the selectivity of the catalyst, improve product distribution, increase the yield of gasoline and diesel in the product, and reduce the output of dry gas at the same time.

[0004] In Feng Ming's article "Research on Alternative Pre-lifting Medium for Catalytic Cracking", dry gas and gasoline were used as pre-lifting alternative media to conduct experimental research on their pre-lifting effects. It was found that dry gas as a pre-lifting medium can not only reduce gas yield and inhibit coke formation, but also change the composition of gas phase products, while gasoline pre-lifting can increase propylene production. The role of pre-lifting gas is to lift the high-temperature regenerated catalyst to the raw material nozzle, so that the catalyst and raw materials are fully mixed and contacted, which is conducive to reducing coke formation. Using dry gas instead of steam as a pre-lifting medium can reduce the hydrothermal deactivation of the catalyst, reduce and catalyst thermal collapse, thereby reducing catalyst loss, and can reduce the emission of acidic water. However, the main components of dry gas are C1, C2 and H2, which are difficult to compress due to their low molecular weight, which significantly increases the energy consumption of the air compressor, increases the load of the absorption stabilization system, reduces the absorption effect, and leads to a high C3 content in the dry gas, resulting in waste of components above C3. The pre-lifted dry gas circulates in the reactor, air compressor, absorption, and desorption systems, which increases the load of the cooler and desorption tower reboiler, and increases the energy consumption of the device.

[0005] In Li Yahua's article "The Influence of Different Pre-lifting Media on the Separation Process of Catalytic Cracking Unit", it was found that when dry gas is used as the pre-lifting medium, the air compressor load increases greatly, which is 1.36 times the air compressor load during steam pre-lifting; the gas phase load of each tower will increase, and the reboiler load will increase significantly. The specific values ​​are shown in the following table, where operating condition 1 is steam pre-lifting and operating condition 2 is dry gas pre-lifting.

[0006] Summary of the invention

[0007] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a petroleum catalytic cracking system, which can overcome the defects of the existing riser reactor pre-lifter lifting medium resulting in high energy consumption of the gas compressor, large load on the absorption stabilization system, low absorption effect, high C3 content in the dry gas, and waste of components above C3.

[0008] The specific technical solution of the embodiment of the present invention is:

[0009] A petroleum catalytic cracking system, comprising:

[0010] A riser unit, wherein the riser unit is used as a crude oil reactor;

[0011] a fractionation unit, wherein an inlet of the fractionation unit is in communication with an outlet of the riser unit;

[0012] an oil-gas separator, the oil-gas separator being in communication with an outlet of the fractionation unit;

[0013] A compression unit, wherein the inlet of the compression unit is connected to the oil and gas outlet of the oil and gas separator;

[0014] a gas-liquid separator, wherein the inlet of the gas-liquid separator is connected to the outlet of the compression unit, the gas-liquid separator has a gas outlet and a liquid outlet, and the gas-liquid separator is used to separate the oil and gas compressed by the compression unit into condensed oil and rich gas, wherein the rich gas includes C3 components and C4 components;

[0015] A subsequent processing unit, the subsequent processing unit is connected to the gas outlet of the gas-liquid separator, and the subsequent processing unit is used to process the rich gas to obtain dry gas output;

[0016] A cooler connected between the outlet of the compression unit and the inlet of the gas-liquid separator;

[0017] A condensed oil storage tank, wherein the gas-liquid separator is arranged in the condensed oil storage tank, wherein the condensed oil storage tank comprises a horizontal section of the storage tank extending in the horizontal direction, a vertical section of the storage tank extending in the vertical direction, and an input pipe, the upper end of the side wall of the horizontal section of the storage tank has an opening, and the lower end of the vertical section of the storage tank is open and sealed at the opening; the gas-liquid separator is arranged in the vertical section of the storage tank, and the side wall of the vertical section of the storage tank has a gas outlet; the input pipe is inserted into the vertical section of the storage tank from top to bottom, the gas-liquid separator is connected to the lower end of the input pipe, and the gas outlet is higher than the gas-liquid separator; the horizontal section of the storage tank has a liquid outlet; the gas-liquid separator comprises one of the following: a cantilever gas-liquid separator, a cyclone gas-liquid separator;

[0018] A mixing unit, wherein a first inlet of the mixing unit is connected to a gas outlet of the gas-liquid separator, and a second inlet of the mixing unit is connected to a dry gas outlet of the subsequent processing unit;

[0019] A first pipeline, one end of which is connected to the outlet of the mixing unit, and the other end of which is connected to the inlet of the riser unit, so that the mixed dry gas and rich gas are input to the inlet of the riser unit as a lifting medium for the crude oil.

[0020] Preferably, the first inlet of the mixing unit is connected to the gas outlet of the gas-liquid separator through a second pipeline; a first liquid content detection device is provided on the second pipeline, and the first liquid content detection device is used to detect the liquid content in the rich gas flowing through the second pipeline.

[0021] Preferably, the second inlet of the mixing unit is connected to the dry gas outlet of the subsequent processing unit through a third pipeline, and a flow regulating unit is provided on the third pipeline; a second liquid content detection device is provided on the first pipeline, and the second liquid content detection device is used to detect the liquid content in the mixed dry gas and the rich gas flowing through the first pipeline;

[0022] The flow regulating unit is electrically connected to the first liquid content detection device and the second liquid content detection device; when the flow regulating unit detects that the liquid volume percentage in the rich gas flowing through the second pipeline exceeds 5%, the flow regulating unit regulates the flow of the dry gas flowing through the third pipeline so that the liquid volume percentage in the gas at the outlet of the mixing unit detected by the second liquid content detection device does not exceed 3%.

[0023] Preferably, the riser unit comprises: a riser main section, and a riser pre-lifting section connected below the riser main section, wherein the diameter of the riser pre-lifting section is smaller than that of the riser main section;

[0024] A first nozzle is provided on the side wall of the main section of the riser, and the first nozzle is used to input the crude oil into the main section of the riser;

[0025] The other end of the first pipeline is communicated with the bottom inlet of the pre-lifting section of the riser.

[0026] Preferably, a second nozzle is provided on the side wall of the main section of the riser, the second nozzle is located below the first nozzle, and the second nozzle is used to input gasoline, diesel or recycled oil into the main section of the riser;

[0027] The first pipeline includes a first pipeline main line and a plurality of first pipeline branch lines connected to the first pipeline main line, the first pipeline main line is connected to the outlet of the mixing unit, some of the first pipeline branch lines are connected to the atomizing medium inlet of the second nozzle, and some of the first pipeline branch lines are connected to the bottom inlet of the pre-lifting section of the riser.

[0028] Preferably, a heating unit for heating the mixed dry gas and rich gas flowing through the first pipeline is provided on the first pipeline, so that the temperature of the gas input to the second nozzle reaches between 180 degrees Celsius and 220 degrees Celsius.

[0029] Preferably, a first flow regulating valve is provided on the second pipeline; and a second flow regulating valve is provided on the first pipeline.

[0030] Preferably, the subsequent processing unit includes:

[0031] A desorption tower, an absorption tower and a reabsorption tower are connected in sequence, the inlet of the desorption tower is connected to the gas outlet of the gas-liquid separator, and the outlet of the reabsorption tower is used to output dry gas.

[0032] The technical solution of the present invention has the following significant beneficial effects:

[0033] 1. Since the mixed rich gas and dry gas are used as the lifting medium of the raw oil, the main components of the rich gas can be increased by C3 component and a small amount of C4 component on the basis of dry gas. The C3 component basically does not participate in the reaction in the lifting pipe unit and the reaction tank, has no adverse effect on the reaction, and does not enter the subsequent subsequent processing unit, so the load of the desorption tower, the absorption tower and the reabsorption tower can be reduced. In particular, with the presence of C3 and C4 components, the proportion of C1 and C2 components can be reduced. Therefore, at the inlet of the compression unit, the relative molecular weight of the inflowing medium (rich gas) will increase compared with before, which reduces the difficulty of gas compression and reduces the energy consumption of the compression unit.

[0034] 2. Since the gas-liquid separator inputs the rich gas separated from the oil and gas compressed by the compression unit into the riser as the lifting medium of the crude oil, it will reduce the load of the subsequent processing unit, thereby improving the absorption effect of the subsequent processing unit. For example, the load of the absorption tower and the desorption tower can be reduced to improve their absorption effect, so that the C3 component in the dry gas output from the subsequent processing unit can be further reduced. It can also reduce the circulation volume of the dry gas in the riser unit, the fractionation unit, the oil-gas separator, the compression unit, the cooler, and the subsequent processing unit, reducing the load of the cooler and the subsequent processing unit, such as the load of the desorption tower reboiler, reducing the steam consumption, reducing the hydrothermal deactivation of the catalyst, reducing the thermal collapse of the catalyst, thereby reducing the catalyst loss, and can reduce the emission of acidic water and reduce energy consumption.

[0035] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with features in other embodiments, or replace features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0037] Figure 1 This is a schematic structural diagram of a petroleum catalytic cracking system in a first embodiment of the present invention;

[0038] Figure 2 This is a schematic structural diagram of a petroleum catalytic cracking system in a second embodiment of the present invention;

[0039] Figure 3 It is a schematic diagram of the structure of the gas-liquid separator and the condensed oil storage tank in the embodiment of the present invention.

[0040] Reference numerals in the above drawings:

[0041] 1. Riser unit; 11. Riser main section; 111. First nozzle; 112. Second nozzle; 12. Riser pre-lifting section; 13. Reactor; 2. Fractionation unit; 3. Oil-gas separator; 4. Compression unit; 5. Gas-liquid separator; 6. Subsequent treatment unit; 61. Desorption tower; 62. Absorption tower; 63. Reabsorption tower; 7. Mixing unit; 8. First pipeline; 81. Second liquid content detection device; 82. First pipeline main line; 83. First pipeline branch line; 84. Second flow regulating valve; 85. Heating unit; 9. Second pipeline; 91. First liquid content detection device; 92. First flow regulating valve; 10. Third pipeline; 101. Flow regulating unit; 14. Condensate oil storage tank; 141. Horizontal section of storage tank; 142. Vertical section of storage tank; 143. Input pipe; 144. Gas outlet; 145. Liquid outlet; 15. Cooler. DETAILED DESCRIPTION

[0042] The details of the present invention can be more clearly understood by combining the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on another element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the communication between the two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0044] In order to overcome the defects of the existing riser reactor pre-lifter lifting medium, resulting in high energy consumption of the gas compressor, large load of the absorption stability system, low absorption effect, high C3 content in the dry gas, and waste of components above C3, a petroleum catalytic cracking system is proposed in this application. Figure 1 This is a schematic diagram of the structure of a petroleum catalytic cracking system in a first embodiment of the present invention. Figure 2 FIG. 1 is a schematic diagram of the structure of the petroleum catalytic cracking system in the second embodiment of the present invention. Figure 1 and Figure 2 As shown, the petroleum catalytic cracking system may include: a riser unit 1, a fractionation unit 2, an oil-gas separator 3, a compression unit 4, a gas-liquid separator 5, a subsequent processing unit 6, a mixing unit 7 and a first pipeline 8.

[0045] like Figure 1 and Figure 2 As shown, the riser unit 1 is used to input crude oil and serves as a crude oil reactor. The crude oil can be transported upward under the action of the lifting gas and then input into the fractionation unit 2. The riser unit 1 can extend in the vertical direction, and a first nozzle 111 can be provided on its side wall. The first nozzle 111 extends into the riser unit 1, and the first nozzle 111 is used to input crude oil into the riser main section 11. The lower end of the riser unit 1 is used to input the lifting gas.

[0046] As feasible, Figure 1 and Figure 2 As shown, in order to ensure uniform mixing between the input gas and materials such as crude oil, the riser unit 1 may include a reaction tank 13 and a riser, the upper end of the riser is inserted into the reaction tank 13, and the reaction tank 13 has an outlet, which may be located at the top of the reaction tank 13.

[0047] As feasible, Figure 1 and Figure 2 As shown, the riser may include: a riser main section 11, and a riser pre-lifting section 12 connected below the riser main section 11, wherein the diameter of the riser pre-lifting section 12 is smaller than the riser main section 11. A first nozzle 111 is provided on the side wall of the riser main section 11, and the first nozzle 111 is used to input crude oil into the riser main section 11.

[0048] like Figure 1 and Figure 2As shown, the inlet of the fractionation unit 2 can be connected to the outlet of the riser unit 1. As feasible, the inlet of the fractionation unit 2 can be connected to the outlet of the reaction tank 13. The fractionation unit 2 can be a fractionation tower, which is mainly used to fractionate the crude oil to obtain the corresponding oil and gas. The oil-gas separator 3 is connected to the outlet of the fractionation unit 2. The oil-gas separator 3 is used to separate the oil and gas from the outlet of the fractionation unit 2. The inlet of the compression unit 4 is connected to the oil and gas outlet of the oil-gas separator 3. The compression unit 4 can generally adopt an air compressor, and the compression unit 4 is used to compress the oil and gas separated by the oil-gas separator 3, and the compressed oil and gas are transported to the gas-liquid separator 5.

[0049] The inlet of the gas-liquid separator 5 is connected to the outlet of the compression unit 4. The gas-liquid separator 5 has a gas outlet 144 and a liquid outlet 145. The gas-liquid separator 5 is used to separate the oil and gas compressed by the compression unit 4 into condensed oil and rich gas, and the rich gas includes C3 components and C4 components. Of course, in addition to C3 components and C4 components, the rich gas also includes dry gas, and the main components of the dry gas are C1 components, C2 components and H2. The rich gas is output through the gas outlet 144, and the condensed oil is output through the liquid outlet 145, so as to ensure that the gas-liquid separator 5 continuously separates the input oil and gas.

[0050] As a feasible method, in order to avoid heat exchange and temperature reduction between the second pipeline 9 and the surrounding environment and cause the appearance of droplets, a cooler 15 is connected between the inlet of the gas-liquid separator 5 and the outlet of the compression unit 4. The cooler 15 is used to cool the compressed oil and gas output from the outlet of the compression unit 4 to a certain extent, so that the gas temperature in the second pipeline 9 is close to the ambient temperature, and then it is transported to the inlet of the gas-liquid separator 5.

[0051] The subsequent processing unit 6 is connected to the gas outlet 144 of the gas-liquid separator 5, and the subsequent processing unit 6 is used to process the rich gas to obtain dry gas output. Figure 1 As shown, the subsequent treatment unit 6 may include an absorption tower 62 and a reabsorption tower 63 connected in sequence from upstream to downstream. Figure 2 As shown, a desorption tower 61 may be connected to the upstream of the absorption tower 62. The inlet of the desorption tower 61 is connected to the gas outlet 144 of the gas-liquid separator 5, and the outlet of the reabsorption tower 63 is used to output dry gas.

[0052] like Figure 1 and Figure 2As shown, the first inlet of the mixing unit 7 is connected to the gas outlet 144 of the gas-liquid separator 5, and the second inlet of the mixing unit 7 is connected to the dry gas outlet of the subsequent processing unit 6. One end of the first pipeline 8 is connected to the outlet of the mixing unit 7, and the other end of the first pipeline 8 is connected to the inlet of the riser unit 1. For example, the other end of the first pipeline 8 is connected to the bottom inlet of the pre-lifting section 12 of the riser. The gas-liquid separator 5 inputs at least part of the rich gas obtained after the condensed oil is separated from the oil and gas compressed by the compression unit 4 to the first inlet of the mixing unit 7, and at least part of the dry gas output from the dry gas outlet of the subsequent processing unit 6 is input to the second inlet of the mixing unit 7. The rich gas and the dry gas are mixed through the mixing unit 7, so that the mixed dry gas and rich gas are input to the inlet of the riser unit 1 as the lifting medium of the crude oil.

[0053] Since the mixed rich gas and dry gas are used as the lifting medium of the crude oil, the main components of the rich gas can be increased by C3 component and a small amount of C4 component on the basis of the dry gas. The C3 component basically does not participate in the reaction in the lifting pipe unit 1 and the reaction tank 13, has no adverse effect on the reaction, and does not enter the subsequent post-processing unit 6, so that the load of the desorption tower 61, the absorption tower 62 and the reabsorption tower 63 can be reduced. In particular, with the presence of C3 and C4 components, the proportion of C1 and C2 components can be reduced. Therefore, at the inlet of the compression unit 4, the relative molecular weight of the inflowing medium (rich gas) will increase compared with before, which reduces the difficulty of gas compression and reduces the energy consumption of the compression unit 4.

[0054] In addition, since the gas-liquid separator 5 inputs the rich gas portion separated from the oil and gas compressed by the compression unit 4 into the riser as the lifting medium of the crude oil, the load of the subsequent processing unit 6 is reduced, thereby improving the absorption effect of the subsequent processing unit 6. For example, the load of the absorption tower 62 and the desorption tower 61 can be reduced to improve their absorption effect, so that the C3 component in the dry gas output from the subsequent processing unit 6 can be further reduced. The circulation amount of the dry gas in the riser unit 1, the fractionation unit 2, the oil-gas separator 3, the compression unit 4, the cooler 15, and the subsequent processing unit 6 can also be reduced, reducing the load of the cooler 15 and the subsequent processing unit 6, such as the load of the reboiler of the desorption tower 61, reducing the steam consumption, reducing the hydrothermal deactivation of the catalyst, reducing the thermal collapse of the catalyst, thereby reducing the catalyst loss, and reducing the acid water discharge and energy consumption.

[0055] In one embodiment, if Figure 2As shown, the first inlet of the mixing unit 7 is connected to the gas outlet 144 of the gas-liquid separator 5 through the second pipeline 9; the second pipeline 9 is provided with a first liquid content detection device 91, and the first liquid content detection device 91 is used to detect the liquid content in the rich gas flowing through the second pipeline 9. In the above manner, the system can obtain and detect the liquid content in the rich gas flowing through the second pipeline 9, so that when the content of liquid or liquid droplets contained in the rich gas flowing through the second pipeline 9 exceeds a certain amount, it can be processed, and the volume percentage content of the liquid or liquid droplets contained in the rich gas flowing through the second pipeline 9 is made to not exceed 5% as much as possible.

[0056] Further, such as Figure 2 As shown, the second inlet of the mixing unit 7 is connected to the dry gas outlet of the subsequent processing unit 6 through the third pipeline 10, and a flow regulating unit 101 is provided on the third pipeline 10. A second liquid content detection device 81 is provided on the first pipeline 8, and the second liquid content detection device 81 is used to detect the liquid content in the mixed dry gas and rich gas flowing through the first pipeline 8. The flow regulating unit 101 can be electrically connected to the first liquid content detection device 91 and the second liquid content detection device 81. When the flow regulating unit 101 detects that the liquid volume percentage in the rich gas flowing through the second pipeline 9 exceeds 5%, the flow regulating unit 101 can adjust the flow of the dry gas flowing through the third pipeline 10 so that the liquid volume percentage in the gas at the outlet of the mixing unit 7 detected by the second liquid content detection device 81 does not exceed 3%. The above method ensures the performance of the mixed rich gas and dry gas as a lifting medium for crude oil.

[0057] As feasible, Figure 2 As shown, in order to control the flow rate of the rich gas obtained by separating the condensed oil from the oil and gas compressed by the compression unit 4 by the gas-liquid separator 5 and inputting it to the first inlet of the mixing unit 7, a first flow regulating valve 92 is provided on the second pipeline 9. In order to control the flow rate of the mixed gas of the rich gas and the dry gas output from the outlet of the mixing unit 7 and inputting it to the inlet of the riser unit 1, a second flow regulating valve 84 is provided on the first pipeline 8.

[0058] In one embodiment, if Figure 2As shown, a second nozzle 112 is provided on the side wall of the main section 11 of the riser, and the second nozzle 112 is located below the first nozzle 111. The second nozzle 112 is used to input gasoline, diesel or recycled oil into the main section 11 of the riser. The first pipeline 8 includes a first pipeline main line 82 and a plurality of first pipeline branch lines 83 connected to the first pipeline main line 82, the first pipeline main line 82 is connected to the outlet of the mixing unit 7, part of the first pipeline branch lines 83 is connected to the atomizing medium inlet of the second nozzle 112, and part of the first pipeline branch lines 83 is connected to the bottom inlet of the pre-lifting section 12 of the riser. In the above manner, the product distribution of the later fractionation tower can be improved, such as adjusting the product quality and optimizing the product ratio, and the operating conditions can also be stabilized, including controlling the feed properties of the fractionation tower and balancing the heat distribution of the fractionation tower. In addition, it can also achieve the goal of improving economic benefits. For example, adding gasoline, diesel, and recycled oil can make full use of the existing product resources within the refinery. For some gasoline and diesel products with slightly poor quality or that do not meet specific standards, they can be reasonably used through blending in the catalytic cracking process to improve resource utilization; by carefully blending and optimizing product quality, the added value of the product can be increased. For example, producing higher quality gasoline and diesel products can get better prices in the market, thereby improving the economic benefits of the refinery.

[0059] Further, such as Figure 2 As shown, a heating unit 85 is provided on the first pipeline 8 for heating the mixed dry gas and rich gas flowing through the first pipeline 8, so that the temperature of the gas input to the second nozzle 112 reaches between 180 degrees Celsius and 220 degrees Celsius. By heating the mixed gas of rich gas and dry gas, it can be used as an atomizing medium for gasoline, diesel, and recycled oil, thereby replacing the original steam, and can effectively prevent the mixed gas from carrying liquid, which is not conducive to atomization.

[0060] In a preferred embodiment, Figure 3 FIG. 1 is a schematic diagram of the structure of the gas-liquid separator and the condensed oil storage tank in cooperation with each other in an embodiment of the present invention. Figure 3As shown, the petroleum catalytic cracking system also includes: a condensed oil storage tank 14, and a gas-liquid separator 5 is arranged in the condensed oil storage tank 14. The condensed oil storage tank 14 includes a storage tank horizontal section 141 extending in the horizontal direction, a storage tank vertical section 142 extending in the vertical direction, and an input pipe 143. The upper end of the side wall of the storage tank horizontal section 141 has an opening, and the lower end of the storage tank vertical section 142 is open and sealed at the opening; the gas-liquid separator 5 is arranged in the storage tank vertical section 142, and the side wall of the storage tank vertical section 142 has a gas outlet 144; the input pipe 143 is inserted into the storage tank vertical section 142 from top to bottom, the gas-liquid separator 5 is connected to the lower end of the input pipe 143, and the gas outlet 144 is higher than the gas-liquid separator 5; the storage tank horizontal section 141 has a liquid outlet 145. The gas-liquid separator 5 can include one of the following: a cantilever gas-liquid separator 5, a cyclone gas-liquid separator 5. Of course, the gas-liquid separator 5 may also adopt other forms of gas-liquid separator 5 that meets the requirements, and this application does not impose any limitation thereto.

[0061] In the above structure, the oil and gas compressed by the compression unit 4 are input into the input pipe 143, and the oil and gas enter the condensed oil storage tank 14 through the input pipe 143, and then reach the gas-liquid separator 5 of the vertical section 142 of the storage tank in the condensed oil storage tank 14, and the condensed oil and the rich gas are separated by the gas-liquid separator 5. The condensed oil flows down to the horizontal section 141 of the storage tank under the action of gravity for storage, and the rich gas can flow upward through the gap between the inner wall of the vertical section 142 of the storage tank and the outer wall of the input pipe 143, and flow out through the gas outlet 144 on the side wall of the vertical section 142 of the storage tank. When there is too much condensed oil in the horizontal section 141 of the storage tank, the condensed oil can be discharged through the liquid outlet 145 of the horizontal section 141 of the storage tank. During the whole process, the condensed oil in the horizontal section 141 of the storage tank will not affect the operation of the gas-liquid separator 5. At the same time, the operation of the entire gas-liquid separator 5 is in the condensed oil storage tank 14, so both the separated condensed oil and rich gas are easy to collect and output accordingly.

[0062] ASPEN calculations show that the energy consumption of the solution using a mixture of rich gas and dry gas as the lifting medium is significantly reduced compared to the traditional dry gas as the lifting medium, as shown in Table 1. In this comparison, the solution using a mixture of rich gas and dry gas as the lifting medium does not use the second nozzle 112 to input gasoline, diesel or recycled oil into the main section 11 of the riser.

[0063] Table 1: ASPENHYSYS simulation energy consumption comparison table

[0064]

[0065] According to the conversion relationship: 1kWh = 3600000J, 1kg standard oil = 41.868MJ, the process simulates the feed of 428t / h, so the energy consumption = {[(8315.4×3600000)×10 -6 ] / 41.868} / 428=1.67kg(standard oil / t)

[0066] According to the simulation results, after the dry gas lifting was changed to the mixed lifting of rich gas and dry gas, the yield of the reaction part product was almost unchanged. The absorption stable energy consumption was reduced by about 1.67kg standard oil / ton, which is equivalent to saving 15.9% of energy consumption. In addition, the supplementary absorbent can reduce about 30t / h, which is a significant effect.

[0067] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0068] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A petroleum catalytic cracking system, characterized in that: The petroleum catalytic cracking system comprises: A riser unit (1), the riser unit (1) being used as a crude oil reactor; A fractionation unit (2), wherein the inlet of the fractionation unit (2) is connected to the outlet of the riser unit (1); An oil-gas separator (3), the oil-gas separator (3) being in communication with an outlet of the fractionation unit (2); A compression unit (4), wherein the inlet of the compression unit (4) is connected to the oil and gas outlet of the oil and gas separator (3); a gas-liquid separator (5), wherein the inlet of the gas-liquid separator (5) is connected to the outlet of the compression unit (4), the gas-liquid separator (5) has a gas outlet (144) and a liquid outlet (145), and the gas-liquid separator (5) is used to separate the oil and gas compressed by the compression unit (4) into condensed oil and rich gas, wherein the rich gas includes a C3 component and a C4 component; a subsequent processing unit (6), the subsequent processing unit (6) being in communication with the gas outlet (144) of the gas-liquid separator (5), and the subsequent processing unit (6) being used for processing the rich gas to obtain dry gas output; a cooler (15), the cooler (15) being connected between the outlet of the compression unit (4) and the inlet of the gas-liquid separator (5); A condensed oil storage tank (14), wherein the gas-liquid separator (5) is arranged in the condensed oil storage tank (14), wherein the condensed oil storage tank (14) comprises a storage tank horizontal section (141) extending in a horizontal direction, a storage tank vertical section (142) extending in a vertical direction, and an input pipe (143), the upper end of the side wall of the storage tank horizontal section (141) has an opening, and the lower end of the storage tank vertical section (142) is open and sealed at the opening; the gas-liquid separator (5) is arranged in the storage tank The storage tank comprises a vertical section (142), and a gas outlet (144) is provided on a side wall of the vertical section (142); the input pipe (143) is inserted into the vertical section (142) of the storage tank from top to bottom, the gas-liquid separator (5) is connected to the lower end of the input pipe (143), and the gas outlet (144) is higher than the gas-liquid separator (5); the storage tank horizontal section (141) has a liquid outlet (145); the gas-liquid separator (5) comprises one of the following: a cantilever gas-liquid separator, a cyclone gas-liquid separator; A mixing unit (7), wherein a first inlet of the mixing unit (7) is connected to a gas outlet (144) of the gas-liquid separator (5), and a second inlet of the mixing unit (7) is connected to a dry gas outlet of the subsequent processing unit (6); A first pipeline (8), one end of which is connected to the outlet of the mixing unit (7), and the other end of which is connected to the inlet of the riser unit (1), so that the mixed dry gas and rich gas are input to the inlet of the riser unit (1) as a lifting medium for the crude oil.

2. The petroleum catalytic cracking system according to claim 1, characterized in that: The first inlet of the mixing unit (7) is connected to the gas outlet (144) of the gas-liquid separator (5) through a second pipeline (9); a first liquid content detection device (91) is provided on the second pipeline (9), and the first liquid content detection device (91) is used to detect the liquid content in the rich gas flowing through the second pipeline (9).

3. The petroleum catalytic cracking system according to claim 2, characterized in that: The second inlet of the mixing unit is connected to the dry gas outlet of the subsequent processing unit (6) through a third pipeline (10), and a flow regulating unit (101) is provided on the third pipeline (10); a second liquid content detection device (81) is provided on the first pipeline (8), and the second liquid content detection device (81) is used to detect the liquid content in the mixed dry gas and the rich gas flowing through the first pipeline (8); The flow regulating unit (101) is electrically connected to the first liquid content detection device (91) and the second liquid content detection device (81); when the flow regulating unit (101) detects that the liquid volume percentage in the rich gas flowing through the second pipeline (9) exceeds 5%, the flow regulating unit (101) regulates the flow of the dry gas flowing through the third pipeline (10) so that the liquid volume percentage in the gas at the outlet of the mixing unit (7) detected by the second liquid content detection device (81) does not exceed 3%.

4. The petroleum catalytic cracking system according to claim 1, characterized in that: The riser unit (1) comprises: a riser main section (11), and a riser pre-lifting section (12) connected below the riser main section (11), wherein the diameter of the riser pre-lifting section (12) is smaller than that of the riser main section (11); A first nozzle (111) is provided on the side wall of the main section (11) of the riser, and the first nozzle (111) is used to input the crude oil into the main section (11) of the riser; The other end of the first pipeline (8) is connected to the bottom inlet of the pre-lifting section (12) of the riser.

5. The petroleum catalytic cracking system according to claim 4, characterized in that: A second nozzle (112) is provided on the side wall of the riser main section (11), the second nozzle (112) is located below the first nozzle (111), and the second nozzle (112) is used to input gasoline, diesel or recycled oil into the riser main section (11); The first pipeline (8) comprises a first pipeline main line (82) and a plurality of first pipeline branch lines (83) connected to the first pipeline main line (82); the first pipeline main line (82) is connected to the outlet of the mixing unit (7); part of the first pipeline branch lines (83) are connected to the atomizing medium inlet of the second nozzle (112); and part of the first pipeline branch lines (83) are connected to the bottom inlet of the pre-lifting section (12) of the lifting pipe.

6. The petroleum catalytic cracking system according to claim 5, characterized in that: The first pipeline (8) is provided with a heating unit (85) for heating the mixed dry gas and rich gas flowing through the first pipeline (8), so that the temperature of the gas input to the second nozzle (112) reaches between 180 degrees Celsius and 220 degrees Celsius.

7. The petroleum catalytic cracking system according to claim 3, characterized in that: The second pipeline (9) is provided with a first flow regulating valve (92); the first pipeline (8) is provided with a second flow regulating valve (84).

8. The petroleum catalytic cracking system according to claim 1, characterized in that: The subsequent processing unit (6) comprises: A desorption tower (61), an absorption tower (62) and a reabsorption tower (63) are connected in sequence, wherein the inlet of the desorption tower (61) is connected to the gas outlet (144) of the gas-liquid separator (5), and the outlet of the reabsorption tower (63) is used to output dry gas.

Images