A method for controlling the proportion of dilution steam in steam cracking of crude oil and application thereof

Abstract

The application discloses a kind of crude oil steam cracking dilution steam proportioning control method and application.This kind of crude oil steam cracking dilution steam proportioning control method includes: obtaining the water content of third mixture flow;The water content of third mixture flow is sent to logic calculator by signal transmission, and the required total dilution steam flow is obtained;According to the required total dilution steam flow obtained, based on the ratio of dilution steam and light component raw hydrocarbon preset, signal is transmitted to dilution steam total flow control valve group, and the total dilution steam injection amount is cascade controlled.The control method of the application can make dilution steam proportioning meet the requirement of set value in real time, ensure the injection ratio of dilution steam under crude oil cracking condition.The steam cracking production low-carbon olefin device of the application can make cracking furnace realize the processing of multiple raw materials from light raw material to heavy raw material, improve the adaptability of device raw material feed and product yield, save project investment.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of crude oil steam cracking dilution steam proportioning control method and application. BACKGROUND

[0002] In recent years, with the increase of shale oil and condensate oil and other light crude oil production, the process route of directly cracking crude oil to produce olefins becomes possible. Among them, the tubular furnace steam cracking technology becomes the main method of directly cracking crude oil to produce low carbon olefins. This method can greatly shorten the process flow, reduce construction investment, greatly expand the selection of raw materials of the device, has broad application prospect, and is of great significance to China's chemical industry.

[0003] Generally in steam cracking reaction, the mixture of the determined proportion of steam and light crude oil raw material is needed, at this time, the mixture is sent into the radiant furnace tube of cracking furnace, and the best cracking yield can be achieved. In the traditional steam cracking process, the flow of light crude oil raw material into the convection section and the radiant section of cracking furnace is consistent, and people usually calculate the dilution steam injection amount according to the raw material flow to realize the setting of the mixing ratio of dilution steam and crude oil raw material, so as to obtain better cracking yield. SUMMARY

[0004] In order to realize the direct steam cracking treatment of crude oil raw material, the present application provides a kind of crude oil steam cracking dilution steam proportioning control method and application, which can not only ensure the stable operation of the device under the condition of crude oil steam cracking and the best product yield, but also simplify the process flow and save cost.

[0005] As an aspect of the present application, it relates to a crude oil steam cracking dilution steam proportioning control method, comprising:

[0006] obtaining the water content of the third mixture flow;

[0007] the water content of the third mixture flow is sent to a logic calculator through signal transmission, and the required total dilution steam flow is calculated;

[0008] According to the calculated total dilution steam flow required, based on the pre-set ratio of dilution steam to light component raw material hydrocarbon, signal is transmitted to the dilution steam total flow control valve group, and the total dilution steam injection amount is controlled in cascade;

[0009] Among them, the water content of the third mixture flow is determined by the following method:

[0010] The crude oil raw material stream is mixed with the first dilution steam stream in the first mixer through the preheating section of cracking furnace, and the first mixture stream is obtained;

[0011] The first mixture stream is passed through the mixing section I of the pyrolysis furnace and then into the second mixer to mix with the superheated second dilution steam stream to obtain the second mixture stream;

[0012] The second mixture is fed into a separation device, where it is separated into light and heavy components, and a third mixture is obtained from the top outlet.

[0013] The water content of the third mixture stream is collected by a water content analysis device installed at the top outlet of the separation device.

[0014] In any specific embodiment, the step of passing the crude oil feedstock through the preheating section of the cracking furnace into the first mixer and mixing it with the first dilution steam feedstock to obtain the first mixture stream includes:

[0015] The crude oil feedstock is fed into the preheating section of the cracking furnace to obtain the preheated crude oil feedstock.

[0016] The crude oil stream enters the first mixer and mixes with the first dilution vapor stream to obtain the first mixture stream.

[0017] In any specific embodiment, the flow rate of the first dilution vapor stream is 0.1 to 10 wt% of the crude oil feedstock stream flow rate, specifically including:

[0018] The crude oil feedstock is fed into the preheating section of the cracking furnace to obtain the preheated crude oil feedstock.

[0019] The flow rate of the first dilution steam stream is controlled to be 0.1 to 10 wt% of the flow rate of the crude oil feed stream, and the first dilution steam stream is fed into the first mixer;

[0020] The preheated crude oil stream is mixed with the first dilution vapor stream in the first mixer to obtain a first mixture stream.

[0021] In any specific embodiment, the step of passing the first mixture stream through the mixing section I of the pyrolysis furnace into the second mixer and mixing it with the superheated second dilution steam stream to obtain the second mixture stream includes:

[0022] The first mixture is passed through the mixing section I of the pyrolysis furnace to obtain the stream that has passed through the mixing section I of the pyrolysis furnace;

[0023] The stream that has passed through the mixing stage I of the pyrolysis furnace is fed into a second mixer and mixed with the superheated second dilution steam stream that has passed through the mixing stage II of the pyrolysis furnace to obtain a second mixture stream.

[0024] In any specific embodiment, the step of introducing the second mixture into the separation device, separating it by light and heavy components, and obtaining the third mixture stream at the top outlet includes:

[0025] The temperature range to be set for the separation device is determined based on the flow rate of the second mixture flow in order to complete the separation of light and heavy components.

[0026] In any specific embodiment, the separation device is one of wire mesh type, blade type or cyclone separator, specifically including:

[0027] The second mixture is fed into the wire mesh, blade, or cyclone separator, where it is separated into light and heavy components, and a third mixture is obtained from the top outlet.

[0028] In any specific embodiment, the pre-set ratio of dilution steam to light component feed hydrocarbon is 0.1 to 10.

[0029] In any specific embodiment, the top outlet pipeline of the separation device is further provided with a sample analysis device, specifically including:

[0030] The sample analysis device is used to collect samples from the third mixture stream and determine the physical properties of the light component feed hydrocarbons.

[0031] As another aspect of the present invention, it relates to the application of the above-mentioned crude oil steam cracking dilution steam ratio control method in the production of low-carbon olefins.

[0032] As another aspect of the present invention, a method for producing low-carbon olefins by steam cracking is provided, the method comprising the above-described crude oil steam cracking dilution steam ratio control method.

[0033] In any specific embodiment, the method further includes:

[0034] The third mixture is fed into the mixing section III of the pyrolysis furnace to obtain the fourth mixture stream;

[0035] The fourth mixture is fed into the radiant section of the pyrolysis furnace to obtain a pyrolysis product stream;

[0036] The pyrolysis product stream was cooled and separated to obtain low-carbon olefins.

[0037] As another aspect of the present invention, an apparatus for producing low-carbon olefins by steam cracking is provided, comprising: a cracking furnace, a first mixer, a second mixer, a separation device, a logic calculator, and a dilution steam total flow control valve group.

[0038] The preheating section of the cracking furnace is used to preheat the incoming crude oil feedstock stream;

[0039] The first mixer is located between the outlet of the preheating section of the cracking furnace and the inlet of the mixing section I of the cracking furnace, and is used to mix the first dilution steam stream and the preheated crude oil feed stream.

[0040] The second mixer is located between the discharge port of the mixing section I of the pyrolysis furnace and the mixing section II of the pyrolysis furnace, and is used to mix the first mixture stream and the superheated second dilution steam stream.

[0041] The outlet of the second mixer is connected to the inlet of the separation device;

[0042] The discharge port at the top of the separation device is connected to the feed port of the radiant section of the pyrolysis furnace;

[0043] The logic calculator is used to calculate the required total dilution steam flow rate based on the water content of the received third mixture stream, and then sends it to the total dilution steam flow rate control valve group.

[0044] The total dilution steam flow control valve group is installed at the feed inlet of the mixing section II of the pyrolysis furnace, and is used to control the total dilution steam injection amount according to the calculated total dilution steam flow rate.

[0045] In any specific embodiment, it further includes: a moisture content analysis device;

[0046] The moisture content analysis device is located at the discharge port at the top of the separation device and is used to collect the water content of the third mixture stream.

[0047] In any specific embodiment, it further includes: a sample analysis device;

[0048] The sample analysis device is located at the outlet at the top of the separation device and is used to collect and determine the physicochemical properties of the light component feed hydrocarbons in the third mixture stream.

[0049] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0050] 1. The present invention provides a method for controlling the dilution steam ratio in crude oil vapor cracking. By measuring the water content of the liquid stream at the top outlet of the gas-liquid separator and calculating the required total dilution steam flow rate, the total dilution steam flow rate control valve group is adjusted to achieve cascade control of the total dilution steam injection amount, so that the dilution steam ratio meets the set value requirements in real time, and ensures the injection ratio of dilution steam under crude oil cracking conditions.

[0051] 2. The mixing device of the steam cracking process for producing low-carbon olefins of the present invention takes into account the cracking conditions of crude oil, and enables the cracking furnace to process a variety of raw materials at the same time, from light feedstocks (such as LPG and naphtha) to heavy feedstocks (such as crude oil and heavy oil). This improves the adaptability of the feedstock and the product yield, enhances the economics of crude oil cracking to olefins technology, and saves project investment.

[0052] 3. The steam cracking method for producing low-carbon olefins used in this invention has a simple process and is easy to implement.

[0053] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0054] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0055] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0056] Figure 1 This is a process flow diagram of the crude oil vapor cracking and dilution steam of the present invention.

[0057] In the diagram: 1. Dilution steam total flow control valve assembly; 2. First mixer; 3. Second mixer; 4. Cracking furnace; 41. Cracking furnace preheating section; 42. Cracking furnace mixing section I; 43. Cracking furnace mixing section II; 44. Cracking furnace mixing section III; 45. Cracking furnace radiant section; 5. Separation device; 6. Moisture content analysis device; 7. Sample analysis device; 8. Logic calculator;

[0058] A. Crude oil feedstock stream; B. First dilution vapor stream; C. First mixture stream; D. Superheated second dilution vapor stream; E. Second mixture stream; F. Third mixture stream; G. Fourth mixture stream; H. Cracking product stream. Detailed Implementation

[0059] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0060] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0061] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0062] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0063] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0064] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0065] It should be understood that the sequence number of each step in the following embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0066] To illustrate the technical solution of this application, specific embodiments are described below.

[0067] The inventors discovered that in existing steam cracking processes, crude oil feedstocks require steam injection and stripping steps before steam cracking to obtain vaporized light components, thereby achieving steam cracking. Currently, there is no process route for directly steam cracking crude oil feedstocks; that is, the process cannot adjust cracking conditions according to the crude oil's operating conditions. When heavy component feedstocks enter the radiant section of the cracking furnace, it significantly affects product yield and even impacts equipment operation and production safety.

[0068] Among the existing dilution steam ratio control schemes for cracking furnaces, the most representative solution can be found in the patent "Dynamic Optimization Method for Industrial Ethylene Cracking Furnaces Throughout the Cycle Based on a Proxy Model" (patent number CN103605325B). The specific operation process of this scheme is briefly described as follows:

[0069] a. The light crude oil feedstock (i.e., the light components vaporized above) is preheated in the convection section of the cracking furnace;

[0070] b. Configure a certain proportion of dilution steam according to the total flow rate of the raw material entering the cracking furnace, generally 0.3 to 0.8 of the raw material amount;

[0071] c. The dilution steam is thoroughly mixed with the raw materials to ensure complete vaporization of the raw materials;

[0072] d. The mixture of raw material and dilution steam is further superheated in the convection section and finally fed into the radiant section of the cracking furnace. However, the inventors believe that this scheme mainly determines the amount of dilution steam injected by the total flow rate into the cracking furnace. In this process, the steam cracking of crude oil (including heavy crude oil) cannot be carried out directly. For the crude oil steam cracking process, after the separation of heavy components that cannot be vaporized, the amount of raw material sent into the radiant section will be less than the total feed amount. This scheme cannot accurately control the dilution steam ratio, which affects the product yield of the cracking furnace and is not conducive to the stable operation of the cracking furnace.

[0073] Based on the aforementioned technical problems and the fact that existing technologies do not meet the inventor's expectations, the inventor made this invention through further research.

[0074] Example 1

[0075] This invention provides a method for controlling the steam ratio in crude oil steam cracking, comprising:

[0076] S101: Obtain the water content of the third mixture stream F;

[0077] The water content of the third mixture stream F is determined in the following manner:

[0078] The crude oil feedstock A is fed into the first mixer 2 through the preheating section 41 of the cracking furnace and mixed with the first dilution steam feedstock B to obtain the first mixture stream C.

[0079] The first mixture C stream is passed through the mixing section 42 of the pyrolysis furnace and then into the second mixer 3 to be mixed with the superheated second dilution steam stream D to obtain the second mixture stream E.

[0080] The second mixture E is fed into the separation device 5, where it is separated by light and heavy components, and the third mixture F is obtained from the top outlet.

[0081] The water content of the third mixture stream F is collected by the water content analysis device 6 installed at the top outlet of the separation device 5.

[0082] In this embodiment of the invention, the step of passing crude oil feedstock A through the cracking furnace preheating section 41 into the first mixer 2 and mixing it with the first dilution steam feedstock B to obtain the first mixture stream C includes:

[0083] The crude oil feedstock A is fed into the preheating section 41 of the cracking furnace to obtain the preheated crude oil feedstock.

[0084] The preheated crude oil stream enters the first mixer 2 and mixes with the first dilution steam stream B to obtain the first mixture stream C.

[0085] In this embodiment of the invention, the flow rate of the first dilution vapor stream B is 0.1 to 10 wt% of the flow rate of the crude oil feedstock stream A, comprising:

[0086] The crude oil feedstock A is fed into the preheating section 41 of the cracking furnace to obtain the preheated crude oil feedstock.

[0087] The flow rate of the first dilution steam stream B is controlled to be 0.1 to 10 wt% of the flow rate of the crude oil feedstock stream A, and the first dilution steam stream B is introduced into the first mixer;

[0088] The preheated crude oil stream is mixed with the first dilution steam stream B in the first mixer 2 to obtain the first mixture stream C.

[0089] In this embodiment of the invention, the step of passing the first mixture stream C through the mixing section 42 of the pyrolysis furnace into the second mixer 3 and mixing it with the superheated second dilution steam stream D to obtain the second mixture stream E includes:

[0090] The first mixture C is passed through the mixing section II 42 of the pyrolysis furnace to obtain the stream that has passed through the mixing section II of the pyrolysis furnace;

[0091] The stream that has passed through the mixing section 41 of the pyrolysis furnace is fed into the second mixer 2 and mixed with the superheated second dilution steam stream D that has passed through the mixing section 42 of the pyrolysis furnace to obtain the second mixture stream E.

[0092] In this embodiment of the invention, the step of introducing the second mixture stream E into the separation device 5, separating it by light and heavy components, and obtaining the third mixture stream F from the top outlet includes:

[0093] The temperature range to be set for the separation device is determined based on the flow rate of the second mixture flow E in order to complete the separation of light and heavy components.

[0094] In this embodiment of the invention, the flow rate of the second mixture stream E determines the temperature range required for the separation device 5, which is generally 450 to 550°C. The temperature required for the separation device 5 is adjusted according to the injection amount of the second mixture stream E, thereby achieving the separation of light and heavy components to improve the utilization rate of oil products and the yield of olefin products. The specific flow rate of the second mixture stream E can be set by those skilled in the art according to the actual situation, and is not specifically limited here.

[0095] In this embodiment of the invention, the separation device 5 is one of a wire mesh type, a blade type, or a cyclone separator, comprising:

[0096] The second mixture E is fed into the wire mesh, blade, or cyclone separator 5, where it is separated into light and heavy components, and a third mixture flow F is obtained from the top outlet.

[0097] In this embodiment of the invention, the pre-set ratio of dilution steam to light component raw material hydrocarbons is 0.1 to 10.

[0098] In this embodiment of the invention, the top outlet pipeline of the separation device 5 is further equipped with a sample analysis device 7. The sample analysis device 7 collects samples from the third mixture stream F and determines the physical properties of the light component feed hydrocarbon, including:

[0099] The third mixture stream F is obtained from the top outlet of the separation device 5. The sample analysis device 7 is used to sample and determine the physicochemical properties of the light component feed hydrocarbon. The measured physicochemical parameters, including but not limited to components and distillation range, are manually compared with the properties of crude oil to ensure that the fourth mixture stream G entering the radiant section 45 of the cracking furnace meets the cracking reaction requirements.

[0100] In this embodiment of the invention, the water content of the third mixture stream F is collected by the water content analysis device 6 installed at the top outlet of the separation device 5.

[0101] In one specific embodiment, the physicochemical properties and parameters of the measured third mixture stream F sample can be as shown in Table 1 below:

[0102] Table 1 Physicochemical properties and parameters of sample F from the third mixture flow

[0103]

[0104]

[0105] S102: The water content of the third mixture flow F is sent to the logic calculator 8 via signal transmission, and the required total dilution steam flow rate is calculated;

[0106] S103: Based on the calculated total dilution steam flow rate, and based on the pre-set ratio of dilution steam to light component raw material hydrocarbons, the signal is transmitted to the total dilution steam flow control valve group 1 to cascade control the total dilution steam injection amount.

[0107] In one specific embodiment, the total dilution steam flow rate required for separating light and heavy components of crude oil with a final boiling point greater than 450°C can be calculated according to the following formula:

[0108] Mass Flow=47.066-0.275API+0.121×DIESEL INDEX -0.039×TBP50-0.02×TBP70

[0109] Mass Flow is the total dilution steam flow rate corresponding to 100 units of crude oil feed.

[0110] API = 141.5 / SG60 / 60°F - 131.5, where SG60 is the density of crude oil at 60°F relative to water at 60°F, and the density of water at 60°F (15.6°C) is 0.99904 g / cm³. 3 ;

[0111] DIESEL INDEX For diesel index;

[0112] TBP50 and TBP70 are the temperatures (°C) corresponding to 50% and 70% of the true boiling point, respectively.

[0113] In this embodiment of the invention, after the total dilution steam flow rate is calculated according to the above formula, the first dilution steam stream B flows into the first mixer 2 at 0.1 to 10 wt% of the crude oil feedstock stream flow rate A, and the remaining dilution steam stream enters the mixing section II 43 of the cracking furnace for heating to form the superheated second dilution steam stream D.

[0114] Example 2

[0115] Based on the same inventive concept, embodiments of the present invention also provide a method for producing low-carbon olefins by steam cracking, including the crude oil steam cracking dilution steam ratio control method described in Embodiment 1 above, and further including:

[0116] S104: The third mixture stream F is fed into the mixing section III 44 of the pyrolysis furnace to obtain the fourth mixture stream G;

[0117] S105: The fourth mixture G is fed into the radiation section 45 of the pyrolysis furnace to obtain the pyrolysis product stream H;

[0118] S106: After cooling and separating the pyrolysis product stream H, low-carbon olefins are obtained.

[0119] In embodiments of the present invention, the low-carbon olefins include, but are not limited to, methane, ethane, ethylene, propane, propylene, butane, butene, etc.

[0120] Example 3

[0121] Based on the same inventive concept, this embodiment of the invention provides an apparatus for producing low-carbon olefins by steam cracking. The method for producing low-carbon olefins by steam cracking described in the above embodiment two is implemented by the production apparatus provided in this embodiment of the invention. The production includes: a cracking furnace 4, a first mixer 2, a second mixer 3, a separation device 5, a moisture content analysis device 6, a sample analysis device 7, a logic calculator 8, and a dilution steam total flow control valve group 1.

[0122] The cracking furnace preheating section 41 is used to preheat the incoming crude oil feedstock A.

[0123] In this embodiment of the invention, crude oil feedstock A can be light crude oil feedstock, including but not limited to: LPG, naphtha, etc.; or it can be heavy crude oil feedstock, including but not limited to: crude oil, heavy oil, etc.

[0124] The first mixer 2 is located between the outlet of the preheating section 41 of the cracking furnace and the inlet of the mixing section 42 of the cracking furnace, and is used to mix the first dilution steam stream B and the preheated crude oil feed stream.

[0125] The second mixer 3 is disposed between the discharge port of the mixing section I 42 of the pyrolysis furnace and the mixing section II 43 of the pyrolysis furnace, and is used to mix the first mixture stream C and the superheated second dilution steam stream D.

[0126] The outlet of the second mixer 3 is connected to the inlet of the separation device 5;

[0127] The discharge port at the top of the separation device 5 is connected to the feed port of the radiant section 45 of the pyrolysis furnace.

[0128] The logic calculator 8 is used to calculate the required total dilution steam flow rate based on the water content of the received third mixture flow F, and send it to the total dilution steam flow control valve group 1;

[0129] The total dilution steam flow control valve group 1 is installed at the feed inlet of the mixing section II 43 of the pyrolysis furnace, and is used to control the total dilution steam flow based on the calculated total dilution steam flow.

[0130] In order to monitor the mixing ratio of the fed crude oil feedstock and dilution steam in real time and ensure the stable operation of the unit and the best product yield under the crude oil steam cracking condition, the steam cracking device for producing low carbon olefins of the present invention further includes: a water content analysis device 6.

[0131] The moisture content analysis device 6 is located at the discharge port at the top of the separation device 5 and is used to collect the water content of the third mixture stream F.

[0132] In order to detect and determine the physicochemical properties of the light component feedstock hydrocarbons, and to facilitate manual comparison of the measured physicochemical parameter information with the properties of crude oil, so as to ensure that the fourth mixture G stream entering the radiant section 45 of the cracking furnace meets the cracking reaction requirements, the steam cracking production apparatus for producing low-carbon olefins of the present invention further includes: a sample analysis device 7.

[0133] The sample analysis device 7 is located at the outlet at the top of the separation device 5 and is used to collect and determine the physical properties of the light component raw hydrocarbons in the third mixture stream F.

[0134] The specific operation process of Embodiment 3 of the present invention can be referred to the detailed description of the method in Embodiments 1 and 2 above, and will not be repeated here.

[0135] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0136] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term “comprising” as used in the specification or claims is interpreted in a manner similar to the term “including,” just as “including,” is interpreted as a conjunction in the claims. Additionally, the use of any term “or” in the specification of the claims is intended to mean “non-exclusive or.”

[0137] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for controlling the proportion of crude oil steam cracking and dilution steam, characterized in that, include: Obtain the water content of the third mixture stream; The water content of the third mixture stream is transmitted to a logic calculator via signal transmission, and the required total dilution steam flow rate is calculated. Since the final boiling point of crude oil is greater than 450℃, the total dilution steam flow rate required for light and heavy component separation of crude oil is calculated according to the following formula: ； Where Mass Flow is the total dilution steam flow rate corresponding to 100 units of crude oil feed; API = 141.5 / SG60 - 131.5, where SG60 is the density of crude oil at 60℉ relative to water at 60℉, and the density of water at 60℉ = 0.99904 g / cm³. 3 ; TBP50 and TBP70 are the diesel fuel indexes; they represent the Celsius temperatures corresponding to 50% and 70% of the actual boiling point, respectively. Based on the calculated total dilution steam flow rate, and based on the preset ratio of dilution steam to light component feed hydrocarbons, the signal is transmitted to the total dilution steam flow control valve group to cascade control the total dilution steam injection amount; the preset ratio of dilution steam to light component feed hydrocarbons is 0.1~10. The water content of the third mixture stream is determined in the following manner: The crude oil feedstock is passed through the preheating section of the cracking furnace and then into the first mixer to be mixed with the first dilution steam feedstock to obtain the first mixture stream; The first mixture stream is passed through the mixing section I of the pyrolysis furnace and then into the second mixer to mix with the superheated second dilution steam stream to obtain the second mixture stream; The second mixture is fed into a separation device, where it is separated into light and heavy components, and a third mixture is obtained from the top outlet. The water content of the third mixture stream is collected by a water content analysis device installed at the top outlet of the separation device.

2. The crude oil steam cracking dilution steam ratio control method according to claim 1, characterized in that, The process of passing crude oil feedstock through the preheating section of a cracking furnace into a first mixer and mixing it with a first dilution steam stream to obtain a first mixture stream includes: The crude oil feedstock is fed into the preheating section of the cracking furnace to obtain the preheated crude oil feedstock. The crude oil stream enters the first mixer and mixes with the first dilution vapor stream to obtain the first mixture stream.

3. The crude oil steam cracking dilution steam ratio control method according to claim 2, characterized in that, The flow rate of the first dilution vapor stream is 0.1~10 wt% of the flow rate of the crude oil feedstock stream, specifically including: The crude oil feedstock is fed into the preheating section of the cracking furnace to obtain the preheated crude oil feedstock. The flow rate of the first dilution steam stream is controlled to be 0.1~10wt% of the flow rate of the crude oil feed stream, and the first dilution steam stream is fed into the first mixer; The preheated crude oil stream is mixed with the first dilution vapor stream in the first mixer to obtain a first mixture stream.

4. The method for controlling the proportion of crude oil steam cracking and dilution steam according to claim 1, characterized in that, The first mixture stream is passed through the mixing section I of the pyrolysis furnace and then introduced into the second mixer to be mixed with the superheated second dilution steam stream to obtain the second mixture stream, which includes: The first mixture is passed through the mixing section I of the pyrolysis furnace to obtain the stream that has passed through the mixing section I of the pyrolysis furnace; The stream that has passed through the mixing stage I of the pyrolysis furnace is fed into a second mixer and mixed with the superheated second dilution steam stream that has passed through the mixing stage II of the pyrolysis furnace to obtain a second mixture stream.

5. The method for controlling the proportion of crude oil steam cracking and dilution steam according to claim 1, characterized in that, The second mixture is fed into a separation device, where it is separated by light and heavy components. A third mixture stream is obtained from the top outlet, comprising: The temperature range to be set for the separation device is determined based on the flow rate of the second mixture flow in order to complete the separation of light and heavy components.

6. The method for controlling the proportion of crude oil steam cracking and dilution steam according to claim 1, characterized in that, The separation device is either a wire mesh type or a cyclone separator, specifically including: The second mixture is fed into the wire mesh or cyclone separator, where it is separated into light and heavy components, and a third mixture is obtained from the top outlet.

7. The method for controlling the proportion of crude oil steam cracking and dilution steam according to claim 1, characterized in that, The top outlet pipeline of the separation device is also equipped with a sample analysis device, specifically including: The sample analysis device is used to collect samples from the third mixture stream and determine the physicochemical properties of the light component feed hydrocarbons.

8. The application of the crude oil steam cracking dilution steam ratio control method as described in any one of claims 1 to 7 in the production of low-carbon olefins.

9. A method for producing low-carbon olefins by steam cracking, characterized in that, The method includes the crude oil steam cracking dilution steam ratio control method according to any one of claims 1 to 7.

10. The method for producing low-carbon olefins by steam cracking according to claim 9, characterized in that, Also includes: The third mixture is fed into the mixing section III of the pyrolysis furnace to obtain the fourth mixture stream; The fourth mixture is fed into the radiant section of the pyrolysis furnace to obtain a pyrolysis product stream; The pyrolysis product stream was cooled and separated to obtain low-carbon olefins.

11. An apparatus for a method of producing low-carbon olefins by steam cracking as described in any one of claims 9 or 10, characterized in that, include: Cracking furnace, first mixer, second mixer, separation device, logic calculator and dilution steam total flow control valve group; The preheating section of the cracking furnace is used to preheat the incoming crude oil feedstock stream; The first mixer is located between the outlet of the preheating section of the cracking furnace and the inlet of the mixing section I of the cracking furnace, and is used to mix the first dilution steam stream and the preheated crude oil feed stream. The second mixer is located between the discharge port of the mixing section I of the pyrolysis furnace and the mixing section II of the pyrolysis furnace, and is used to mix the first mixture stream and the superheated second dilution steam stream. The outlet of the second mixer is connected to the inlet of the separation device; The discharge port at the top of the separation device is connected to the feed port of the radiant section of the pyrolysis furnace; The logic calculator is used to calculate the required total dilution steam flow rate based on the water content of the received third mixture stream, and sends it to the total dilution steam flow rate control valve group; the final boiling point of crude oil is greater than 450℃, and the total dilution steam flow rate required for the separation of light and heavy components of crude oil is calculated according to the following formula: ； Where Mass Flow is the total dilution steam flow rate corresponding to 100 units of crude oil feed; API = 141.5 / SG60 - 131.5, where SG60 is the density of crude oil at 60℉ relative to water at 60℉, and the density of water at 60℉ = 0.99904 g / cm³. 3 ; TBP50 and TBP70 are the diesel fuel indexes; they represent the Celsius temperatures corresponding to 50% and 70% of the actual boiling point, respectively. The total dilution steam flow control valve group is installed at the feed inlet of the mixing section II of the pyrolysis furnace, and is used to control the total dilution steam injection amount according to the calculated total dilution steam flow rate.

12. The apparatus according to claim 11, characterized in that, Also includes: Moisture content analysis device; The moisture content analysis device is located at the discharge port at the top of the separation device and is used to collect the water content of the third mixture stream.

13. The apparatus according to claim 11, characterized in that, It also includes: sample analysis equipment; The sample analysis device is located at the outlet at the top of the separation device and is used to collect and determine the physicochemical properties of the light component feed hydrocarbons in the third mixture stream.

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