A cracking furnace and a method for controlling the outlet temperature of a furnace tube of a cracking furnace

Abstract

The present disclosure relates to a cracking furnace and a method for controlling the outlet temperature of the furnace tubes of the cracking furnace, wherein one furnace chamber is provided with at least one primary fuel main pipe, one primary fuel main pipe is communicated with at least one secondary fuel branch pipe arranged side by side, one secondary fuel branch pipe is corresponded to at least one radiation furnace tube group in the furnace chamber, and is used to provide fuel to the burner corresponding to the at least one radiation furnace tube group corresponding thereto, so that by adjusting the fuel flow through each secondary fuel branch pipe, the control accuracy of the fuel flow into the burner corresponding to each radiation furnace tube group can be significantly improved, and the control accuracy of the outlet average temperature of each radiation furnace tube group can be significantly improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of petroleum chemical industry, in particular to a cracking furnace and a furnace tube outlet temperature control method of the cracking furnace. BACKGROUND

[0002] In the related art, the cracking furnace is used for processing and cracking of various types of cracking raw materials such as gas raw materials, light liquid raw materials and heavy liquid raw materials. Since the cracking conditions of different types of cracking raw materials are quite different, the cracking furnace needs to be optimized and designed based on the main cracking raw materials in terms of cracking performance and operating conditions when it is designed. However, due to the diversity of cracking raw materials, even the cracking furnace suitable for a specific type of cracking raw material also needs to be able to crack other types of cracking raw materials.

[0003] With the in-depth study of the cracking principle, it is gradually realized that high temperature, short residence time and low hydrocarbon partial pressure are helpful to improve the cracking selectivity. However, in the actual control of the cracking furnace, since the radiation furnace tube configuration of the cracking furnace has been determined, the residence time of the cracking raw material in the cracking furnace is basically unchanged under the condition that the raw material feeding amount and properties are unchanged, and at the same time, since the ratio of the cracking raw material to the dilution steam is maintained constant, the hydrocarbon partial pressure in the cracking furnace is also basically unchanged, so in the actual operation, the cracking depth of different types of cracking raw materials is mainly controlled by adjusting the average outlet temperature of the furnace tube of the cracking furnace.

[0004] The existing cracking furnace indirectly controls the average outlet temperature of the furnace tube of each large group of radiation furnace tubes by regulating the flow rate of the raw material flowing through each raw material pipe and regulating the total flow rate of the combustion flowing through the side wall fuel main pipe and the bottom fuel main pipe. Since there is a limit to the flow rate into each large group or each small group of radiation furnace tubes, in order to ensure the same cracking depth, it is necessary to ensure that the flow rate of the raw material into each small group of radiation furnace tubes is the same or within a certain range. Generally, a Venturi is used for flow distribution, and when the flow rate is limited to a certain value, flow deviation will occur, so when the burner corresponding to each large group of radiation furnace tubes cannot be adjusted, accurate control of the average outlet temperature of the furnace tube cannot be achieved. SUMMARY

[0005] The purpose of the present disclosure is to solve the problem that the existing cracking furnace cannot achieve accurate control of the average outlet temperature of the furnace tube, and to provide a cracking furnace and a furnace tube outlet temperature control method of the cracking furnace.

[0006] In order to achieve the above-mentioned purpose, the present disclosure provides a cracking furnace, which comprises a convection section, a radiation section and a plurality of burners, the radiation section has at least one furnace chamber, a plurality of radiation furnace tube groups are arranged in each furnace chamber, each radiation furnace tube group is composed of at least one radiation furnace tube subgroup, and each radiation furnace tube group is communicated with the convection section through a cross-passage tube; the burners are arranged at least at one of the bottom, the sidewall or the top of each furnace chamber, and the arrangement position of the burners is such that one radiation furnace tube group corresponds to at least one burner.

[0007] Among them, at least one primary fuel main pipe is arranged corresponding to one furnace chamber, the primary fuel main pipe is used to provide fuel to all burners corresponding to the furnace chamber; one primary fuel main pipe is communicated with at least one secondary fuel branch pipe arranged in parallel with each other, one secondary fuel branch pipe corresponds to at least one radiation furnace tube group, and the secondary fuel branch pipe is used to provide fuel to the burners corresponding to the at least one radiation furnace tube group corresponding thereto; for a single furnace chamber, a plurality of secondary fuel branch pipes corresponding to a plurality of radiation furnace tube groups arranged in the single furnace chamber are connected in parallel with each other, and then connected in series or in other ways with the primary fuel main pipe corresponding to the single furnace chamber.

[0008] Optionally, one secondary fuel branch pipe corresponds to one radiation furnace tube group, and is used to provide fuel to the burners corresponding to the corresponding radiation furnace tube group.

[0009] Optionally, for a single furnace chamber, one primary fuel main pipe is arranged corresponding to all burners arranged at the bottom of the single furnace chamber, one primary fuel main pipe is arranged corresponding to all burners arranged at the sidewall of the single furnace chamber, and one primary fuel main pipe is arranged corresponding to all burners arranged at the top of the single furnace chamber.

[0010] Optionally, one end of the primary fuel main pipe close to the burners is divided into a first sub-main pipe and a second sub-main pipe, the burners have a primary lance and a secondary lance, for a single primary fuel main pipe, the first sub-main pipe is used to provide fuel to the primary lances of all burners arranged corresponding to the single primary fuel main pipe, and the second sub-main pipe is used to provide fuel to the secondary lances of all burners arranged corresponding to the single primary fuel main pipe; the first sub-main pipe is communicated with at least one secondary fuel branch pipe arranged in parallel with each other, and the second sub-main pipe is communicated with at least one secondary fuel branch pipe arranged in parallel with each other.

[0011] Optionally, a primary regulating valve is arranged on the primary fuel main pipe, and a secondary regulating valve is arranged on the secondary fuel branch pipe.

[0012] Optionally, the primary fuel main pipe is further provided with a total heat value controller, the total heat value controller is used for monitoring actual total heat release of fuel after combustion flowing through the primary fuel main pipe, and when a difference between the actual total heat release and a theoretical total heat value is greater than a first preset value, prompting adjustment of the primary adjusting valve, wherein the theoretical total heat value refers to total heat required for reaching a preset total average temperature of tube outlets of each radiation tube group in a hearth corresponding to the primary fuel main pipe.

[0013] Optionally, for a single radiation tube group, a temperature measuring device is arranged at a tube outlet of each radiation tube subgroup constituting the single radiation tube group, and a subgroup temperature controller corresponding to the single radiation tube group is arranged, and the subgroup temperature controller is connected with each temperature measuring device;

[0014] For a single hearth, a total temperature controller corresponding to the single hearth is arranged, the total temperature controller is connected with the subgroup temperature controllers corresponding to a plurality of radiation tube groups arranged in the single hearth, and the total temperature controller is further connected with the total heat value controller on the primary fuel main pipe corresponding to the single hearth.

[0015] The disclosure further provides a method for controlling a tube outlet temperature of a cracking furnace, the cracking furnace having at least one hearth, and each hearth being arranged with a plurality of radiation tube groups, the method comprising:

[0016] For a single hearth, actual tube outlet average temperatures of each radiation tube group in the single hearth are respectively acquired by temperature measuring devices arranged at tube outlets of each radiation tube subgroup, and an actual total average temperature of all radiation tube groups in the single hearth is determined according to each actual tube outlet average temperature;

[0017] When a difference between the actual total average temperature and a preset total average temperature of tube outlets is greater than a first preset value, a total flow of fuel flowing into a burner corresponding to the single hearth is adjusted, so that the difference between the actual total average temperature and the preset total average temperature of tube outlets is less than the first preset value;

[0018] For a single radiation tube group, when a difference between the actual tube outlet average temperature and a preset tube outlet average temperature is greater than a second preset value, a sub-flow of fuel flowing into a burner corresponding to the single radiation tube group is adjusted, so that the difference between the actual tube outlet average temperature and the preset tube outlet average temperature is less than the second preset value.

[0019] Optionally, according to the actual total average temperature of the outlet of the radiant tubes, the actual total heat consumed by all the groups of radiant tubes in the single hearth is determined, and in the case that the difference between the actual total heat and the theoretical total heat is greater than a third preset value, the total flow of fuel flowing into the burners corresponding to the single hearth is adjusted so that the difference between the actual total heat and the theoretical total heat is less than the third preset value, wherein the theoretical total heat refers to the total heat required to make the total average temperature of the outlet of each group of radiant tubes in the single hearth reach a preset total average temperature of the outlet of the radiant tubes.

[0020] Optionally, at least one primary fuel main pipe corresponding to one of the hearths is provided, and the primary fuel main pipe is used to supply fuel to the burners provided in the hearth, preferably, one primary fuel main pipe is provided corresponding to all the burners provided at the bottom of the hearth, all the burners provided at the sidewall of the hearth, and all the burners provided at the top of the hearth, respectively.

[0021] The total flow of fuel flowing into all the burners corresponding to the primary fuel main pipe is adjusted by adjusting a primary adjusting valve provided on the primary fuel main pipe.

[0022] Optionally, one of the primary fuel main pipes communicates with a plurality of secondary fuel branch pipes arranged side by side, and one of the secondary fuel branch pipes corresponds to at least one of the groups of radiant tubes, and the secondary fuel branch pipe is used to supply fuel to the burners corresponding to the at least one group of radiant tubes corresponding thereto,

[0023] The sub-flow of fuel flowing into the burners corresponding to the single group of radiant tubes is adjusted by adjusting a secondary adjusting valve provided on the secondary fuel branch pipe corresponding to the single group of radiant tubes.

[0024] Optionally, the actual total average temperature of the outlet of all the groups of radiant tubes in the single hearth is determined according to the actual average temperature of the outlet of each of the radiant tubes, comprising:

[0025] The arithmetic mean of the actual average temperature of the outlet of each of the radiant tubes is determined as the actual total average temperature of the outlet of the radiant tubes.

[0026] By the technical scheme, the cracking furnace provided by the present disclosure has at least one primary fuel main pipe corresponding to one furnace chamber, one primary fuel main pipe is communicated with at least one secondary fuel branch pipe arranged in parallel, one secondary fuel branch pipe corresponds to at least one radiation furnace pipe group in the furnace chamber, and is used for supplying fuel to the burner corresponding to the at least one radiation furnace pipe group, thus, by adjusting the fuel flow through each secondary fuel branch pipe, the control accuracy of the fuel flow into the burner corresponding to each radiation furnace pipe group can be significantly improved, and the control accuracy of the average temperature of the furnace pipe outlet of each radiation furnace pipe group can be significantly improved.

[0027] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0029] Figure 1 A structural schematic diagram of a prior cracking furnace is schematically shown;

[0030] Figure 2 A structural schematic diagram of a cracking furnace according to an embodiment of the present disclosure is schematically shown;

[0031] Figure 3 A structural schematic diagram of another cracking furnace according to an embodiment of the present disclosure is schematically shown;

[0032] Figure 4 A structural schematic diagram of still another cracking furnace according to an embodiment of the present disclosure is schematically shown.

[0033] LIST OF ELEMENTS

[0034] 1 convection section 2 radiation section

[0035] 3 burner 4 furnace chamber

[0036] 5 radiation furnace pipe group 6 side wall fuel main pipe

[0037] 7 bottom fuel main pipe 8 side wall regulating valve

[0038] 9 bottom regulating valve 10 cross pipe

[0039] 11 primary fuel main pipe 12 secondary fuel branch pipe

[0040] 13 primary regulating valve 14 secondary regulating valve

[0041] 15 total heat value controller 16 temperature measuring device

[0042] 17 Group temperature controller 18 Main temperature controller Detailed Implementation

[0043] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0044] Figure 1 A schematic diagram of the structure of an existing pyrolysis furnace is shown, such as Figure 1 As shown, the existing pyrolysis furnace includes a convection section 1, a radiant section 2, and multiple burners 3. The radiant section has at least one furnace chamber 4, and multiple radiant furnace tube groups 5 are arranged inside each furnace chamber 4. The burners 3 are located on the side walls and bottom of the furnace chamber 4 to provide heat to each radiant furnace tube group 5. The fuel supplied to the side wall burners is provided by a side wall fuel main pipe 6, and the fuel supplied to the bottom burners is provided by a bottom fuel main pipe 7. A side wall regulating valve 8 is installed on the side wall fuel main pipe to regulate the total fuel flow rate supplied to the side wall burners, and a bottom regulating valve 9 is installed on the bottom fuel main pipe to regulate the total fuel flow rate supplied to the bottom burners.

[0045] The inventors of this disclosure have discovered through research that Figure 1 In the pyrolysis furnace shown, the fuel flow to all sidewall burners can only be regulated through a single sidewall fuel main and its sidewall control valve, and the fuel flow to all bottom burners can only be regulated through a single bottom fuel main and its bottom regulating valve. This configuration allows for control of the overall average outlet temperature of all radiant furnace tube groups by adjusting the total fuel flow to the sidewall and bottom burners. However, this configuration is not suitable for controlling the average outlet temperature of the furnace tubes under at least the following three operating conditions:

[0046] (1) When all radiant furnace tube groups are used to crack the same cracking feedstock, the average outlet temperature of the furnace tubes of each radiant furnace tube group may vary greatly because the combustion conditions of the burners corresponding to each radiant furnace tube group may be different. In order to reduce this difference, the feedstock flow rate entering each radiant furnace tube group is usually adjusted. This will result in different radiant furnace tube flow rates in different groups, and thus the flow rate entering each group will be different. This will lead to different cracking depths of the cracking feedstock between different groups due to different residence times, which will further lead to coking of the radiant furnace tubes, seriously affecting the operating cycle of the cracking furnace and the normal operation of the unit.

[0047] (2) When a pyrolysis furnace is used to pyrolyze multiple pyrolysis feedstocks at the same time, different radiant furnace tube groups may be used to pyrolyze different pyrolysis feedstocks. Since the pyrolysis performance of different pyrolysis feedstocks varies greatly, it is necessary to set different furnace tube outlet average temperatures for radiant furnace tube groups that pyrolyze different pyrolysis feedstocks so that different pyrolysis feedstocks have appropriate pyrolysis depths.

[0048] (3) In practical applications, in order to improve the online rate of the cracking furnace, it is often necessary to crack some of the radiant furnace tube groups for cracking raw materials and clean some of the radiant furnace tube groups for coking. This requires setting different average furnace tube outlet temperatures for the cracking side radiant furnace tube groups and the coking side radiant furnace tube groups.

[0049] Therefore, existing pyrolysis furnaces cannot achieve precise control of the average outlet temperature of each large group of radiant furnace tubes under at least the above three operating conditions. Specifically, existing pyrolysis furnaces cannot meet at least the following three requirements:

[0050] (1) When all radiant furnace tube groups are used to crack the same cracking feedstock and the flow rate is required to be the same, each radiant furnace tube group is required to have the same average furnace tube outlet temperature.

[0051] (2) When different radiant furnace tube groups are used to crack different cracking raw materials, the radiant furnace tube groups that crack different cracking raw materials are required to have different average furnace tube outlet temperatures.

[0052] (3) When some radiant furnace tube groups are used for cracking raw materials and others are used for coking, the radiant furnace tube groups on the cracking side and the radiant furnace tube groups on the coking side are required to have different average furnace tube outlet temperatures.

[0053] To address the aforementioned problems, this disclosure provides a pyrolysis furnace.

[0054] Figure 2 A schematic diagram of the structure of a pyrolysis furnace according to an embodiment of the present disclosure is shown, such as... Figure 2 As shown, the pyrolysis furnace may include a convection section 1, a radiation section 2, and multiple burners 3. The radiation section 2 has at least one furnace chamber 4, and each furnace chamber 4 contains multiple radiant furnace tube groups 5. Each radiant furnace tube group 5 consists of at least one radiant furnace tube subgroup, and each radiant furnace tube group 5 is connected to the convection section 1 via a cross tube 10. The burners 3 are located at least one location in the bottom, side wall, or top of each furnace chamber 4. Figure 2 In the furnace 4, the burner 3 is disposed at the bottom of the furnace chamber 4, and the position of the burner 3 is such that one group of radiant furnace tubes 5 corresponds to at least one burner 3.

[0055] Wherein, one of said hearth 4 corresponds to at least one primary fuel main pipe 11, said primary fuel main pipe 11 is used to provide fuel to all burners 3 corresponding to said hearth 4; one of said primary fuel main pipe 11 communicates with at least one secondary fuel branch pipe 12 which is parallel to each other, one of said secondary fuel branch pipe 12 corresponds to at least one said radiation furnace tube group 5, said secondary fuel branch pipe 12 is used to provide fuel to the burners 3 corresponding to at least one said radiation furnace tube group 5 corresponding to it; for a single hearth 4, a plurality of said secondary fuel branch pipes 12 corresponding to a plurality of said radiation furnace tube groups 5 arranged in said single hearth 4 are connected in parallel to each other, and then connected in parallel and / or series with said primary fuel main pipe 11 corresponding to said single hearth 4.

[0056] In the present disclosure, specifically, during the operation of said cracking furnace, for a single hearth, fuel from the boundary zone first enters the corresponding primary fuel main pipe, then according to the actual needs, it is divided into the parallelly arranged secondary fuel branch pipes corresponding to each radiation furnace tube group, and finally it is divided from the secondary fuel branch pipes into each burner corresponding to each radiation furnace tube group.

[0057] Through the present disclosure, one hearth corresponds to at least one primary fuel main pipe, one primary fuel main pipe communicates with at least one secondary fuel branch pipe which is parallel to each other, one secondary fuel branch pipe corresponds to at least one radiation furnace tube group in the hearth, and is used to provide fuel to the burners corresponding to at least one radiation furnace tube group corresponding to it, therefore, by adjusting the fuel flow through each secondary fuel branch pipe, the control accuracy of the fuel flow into the burners corresponding to each radiation furnace tube group can be significantly improved, thereby the control accuracy of the average temperature of the furnace tube outlet of each radiation furnace tube group can be significantly improved.

[0058] Specifically, the cracking furnace of the present disclosure has the following advantages:

[0059] (1) In the case that all radiation furnace tube groups are used to crack the same cracking raw material and ensure the same flow rate, by adjusting the fuel flow through each secondary fuel branch pipe, the deviation of the average temperature of the furnace tube outlet of each radiation furnace tube group can be close to zero, which not only is beneficial to the long-period stable operation of the cracking furnace and prolongs the service life of the radiation furnace tube, but also is beneficial to improving the stability of product quality;

[0060] (2) In the case that different radiation furnace tube groups are used to crack different cracking raw materials, by adjusting the fuel flow through each secondary fuel branch pipe, the radiation furnace tube groups cracking different cracking raw materials can have different average temperatures of the furnace tube outlet, which can ensure that different cracking raw materials maintain appropriate cracking depth during cracking, thereby overcoming the influence of grouping cracking of different types of cracking raw materials on the cracking furnace, achieving the maximization of the benefits of the target cracking products and the smooth operation of the cracking furnace;

[0061] (3) In the case that cracking of cracking raw materials is carried out in part of the radiation furnace tube groups and part of the radiation furnace tube groups is used for decoking, by adjusting the fuel flow rate flowing through each secondary fuel branch pipe, the radiation furnace tube groups for cracking and the radiation furnace tube groups for decoking can have different average outlet temperatures of the furnace tubes, so that the case of decoking of part of the radiation furnace tube groups is realized without affecting the overall operation of the cracking furnace, which can significantly improve the on-line rate of the cracking furnace and maximize the benefit of the cracking furnace.

[0062] According to the present disclosure, in order to further improve the control accuracy of the average outlet temperature of the furnace tubes of each radiation furnace tube group, preferably, one of the secondary fuel branch pipes 12 corresponds to one of the radiation furnace tube groups 5 and is used to provide fuel to the burners 3 corresponding to the corresponding radiation furnace tube group 5.

[0063] According to the present disclosure, for a single furnace, all burners arranged at the bottom of the single furnace, all burners arranged at the side wall of the single furnace, and all burners arranged at the top of the single furnace can respectively correspond to one of the primary fuel main pipes.

[0064] According to the present disclosure, one end of the primary fuel main pipe close to the burner can be divided into a first sub-main pipe and a second sub-main pipe, the burner has a primary lance and a secondary lance, for a single primary fuel main pipe, the first sub-main pipe is used to provide fuel for the primary lance of all burners arranged corresponding to the single primary fuel main pipe, and the second sub-main pipe is used to provide fuel for the secondary lance of all burners arranged corresponding to the single primary fuel main pipe; the first sub-main pipe is in communication with at least one secondary fuel branch pipe arranged side by side, and the second sub-main pipe is in communication with at least one secondary fuel branch pipe arranged side by side.

[0065] According to the present disclosure, in order to more conveniently realize the regulation and control of the fuel flow rate flowing through the primary fuel main pipe and the secondary fuel branch pipe, preferably, a primary regulating valve 13 can be arranged on the primary fuel main pipe 11, and a secondary regulating valve 14 can be arranged on the secondary fuel branch pipe 12.

[0066] According to the present disclosure, a total heat value controller 15 can also be arranged on the primary fuel main pipe 11, the total heat value controller 15 is used to monitor the actual total heat release after the fuel flowing through the primary fuel main pipe 11 is burned, and when the difference between the actual total heat release and the theoretical total heat is greater than a first preset value, the primary regulating valve 13 is adjusted, wherein the theoretical total heat refers to the total heat required to make the total average outlet temperature of the furnace tubes of each radiation furnace tube group 5 in the furnace 4 corresponding to the primary fuel main pipe 11 reach a preset total average outlet temperature of the furnace tubes.

[0067] In this disclosure, specifically, the primary fuel main pipe is used to provide the fuel required for the cracking of the pyrolysis feedstock to all the radiant furnace tube groups in a single furnace. After these fuels enter the burner and are burned, the heat provided can make the total average temperature of the furnace tube outlets of all the radiant furnace tube groups in a single furnace reach the preset total average temperature of the furnace tube outlets.

[0068] The total average temperature at the furnace tube outlet refers to the arithmetic mean of the average temperatures at the furnace tube outlets of each radiant furnace tube group. The preset total average temperature at the furnace tube outlet can be set according to the type of pyrolysis feedstock in each radiant furnace tube group. The purpose of setting this temperature is to ensure that the pyrolysis feedstock in all radiant furnace tube groups has a suitable pyrolysis depth.

[0069] According to this disclosure, for a single radiant furnace tube group 5, a temperature measuring device 16 is provided at the furnace tube outlet of each radiant furnace tube subgroup that makes up the single radiant furnace tube group 5. A group temperature controller 17 is provided for each radiant furnace tube group 5, and the group temperature controller 17 is connected to each of the temperature measuring devices 16. For a single furnace chamber 4, a total temperature controller 18 is provided for each single furnace chamber 4. The total temperature controller 18 is connected to the group temperature controllers 17 corresponding to the multiple radiant furnace tube groups arranged in the single furnace chamber. The total temperature controller 18 is also connected to the total calorific value controller 15 on the primary fuel main pipe 11 corresponding to the single furnace chamber 4.

[0070] In this disclosure, specifically, the temperature measuring device is used to detect the furnace tube outlet temperature of each radiant furnace tube group; the group temperature controller is used to obtain the furnace tube outlet temperature of each radiant furnace tube group from each of the temperature measuring devices, and determine the arithmetic mean of the furnace tube outlet temperatures of each radiant furnace tube group as the furnace tube outlet average temperature of the radiant furnace tube group; the total temperature controller is used to obtain the furnace tube outlet average temperature of each radiant furnace tube group from each of the group temperature controllers, and determine the arithmetic mean of the furnace tube outlet average temperatures of each radiant furnace tube group as the total average furnace tube outlet temperature of all radiant furnace tube groups in the single furnace chamber; the total calorific value controller is used to obtain the total average furnace tube outlet temperature from the total temperature controller, and calculate the actual total heat release after combustion of the fuel flowing through the primary fuel main pipe based on the total average furnace tube outlet temperature.

[0071] Figure 3 This schematic diagram illustrates the structure of another pyrolysis furnace according to an embodiment of the present disclosure, and... Figure 2 The difference is that the burners in this pyrolysis furnace are located at the bottom and side walls of the furnace chamber. Figure 4 A schematic diagram of the structure of another pyrolysis furnace according to an embodiment of the present disclosure is shown. Figure 2 The difference is that the burner in this pyrolysis furnace is located on the side wall of the furnace chamber.

[0072] The second aspect of the present disclosure provides a method for controlling outlet temperature of furnace tubes of a cracking furnace, the cracking furnace having at least one furnace chamber, each of the furnace chambers being arranged with a plurality of large groups of radiant furnace tubes, the method comprising operations S110-S130.

[0073] In operation S110, for a single furnace chamber, actual average outlet temperatures of the large groups of radiant furnace tubes in the single furnace chamber are respectively obtained by temperature measuring devices arranged at the outlet of each small group of radiant furnace tubes, and an actual total average outlet temperature of all the large groups of radiant furnace tubes in the single furnace chamber is determined according to the actual average outlet temperatures.

[0074] In the present disclosure, specifically, the method for obtaining the average outlet temperature of each large group of radiant furnace tubes can be a common method in the field, which utilizes the temperature measuring devices arranged at the outlet of each small group of radiant furnace tubes to obtain the outlet temperature of each small group of radiant furnace tubes, and then takes the arithmetic mean of the outlet temperatures of each small group of radiant furnace tubes as the average outlet temperature of each large group of radiant furnace tubes.

[0075] Further, after obtaining the actual average outlet temperatures of each large group of radiant furnace tubes, the arithmetic mean of the actual average outlet temperatures can be determined as the actual total average outlet temperature.

[0076] Next, in operation S120, if the difference between the actual total average outlet temperature and the preset total average outlet temperature is greater than a first preset value, the total flow of fuel flowing into the burner corresponding to the single furnace chamber is adjusted so that the difference between the actual total average outlet temperature and the preset total average outlet temperature is less than the first preset value.

[0077] Optionally, the present disclosure can further comprise: determining an actual total heat consumed by all the large groups of radiant furnace tubes in the single furnace chamber according to the actual total average outlet temperature, and adjusting the total flow of fuel flowing into the burner corresponding to the single furnace chamber if the difference between the actual total heat and a theoretical total heat is greater than a third preset value, so that the difference between the actual total heat and the theoretical total heat is less than the third preset value, wherein the theoretical total heat refers to the total heat required to make the total average outlet temperature of each large group of radiant furnace tubes in the single furnace chamber reach the preset total average outlet temperature.

[0078] In the present disclosure, specifically, one of the hearths can correspond to be provided with at least one primary fuel main pipe for providing fuel to burners provided in the hearth, preferably, all of the burners provided at the bottom of the hearth, all of the burners provided at the sidewall of the hearth and all of the burners provided at the top of the hearth can correspond to be provided with one of the primary fuel main pipes respectively; by adjusting a primary adjusting valve provided on the primary fuel main pipe, the total flow of fuel flowing into all of the burners corresponding to the primary fuel main pipe is adjusted.

[0079] Next, in operation S130, for a single radiant furnace tube group, in a case where the difference between the actual furnace tube outlet average temperature and the preset furnace tube outlet average temperature is greater than a second preset value, a sub-flow of fuel flowing into burners corresponding to the single radiant furnace tube group is adjusted so that the difference between the actual furnace tube outlet average temperature and the preset furnace tube outlet average temperature is less than the second preset value.

[0080] In the present disclosure, specifically, one of the primary fuel main pipes is in communication with a plurality of secondary fuel branch pipes arranged side by side with each other, one of the secondary fuel branch pipes corresponds to at least one of the radiant furnace tube groups, the secondary fuel branch pipe is used to provide fuel to burners corresponding to at least one of the radiant furnace tube groups corresponding thereto, and a sub-flow of fuel flowing into burners corresponding to the single radiant furnace tube group can be adjusted by adjusting a secondary adjusting valve provided on the secondary fuel branch pipe corresponding to the single radiant furnace tube group.

[0081] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0082] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present disclosure will not further describe various possible combination manners.

[0083] In addition, various different embodiments of the present disclosure can also be combined in any manner as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A cracking furnace, characterized by, The cracking furnace comprises a convection section, a radiation section having at least one furnace chamber, and a plurality of burners, each of the furnace chambers is arranged with a plurality of radiation furnace tube groups, each of the radiation furnace tube groups is composed of at least one radiation furnace tube subgroup, each of the radiation furnace tube groups is communicated with the convection section through a cross-tube; the burners are arranged at least in one of the bottom, the sidewall or the top of each of the furnace chambers, and the burners are arranged at positions such that one of the radiation furnace tube groups corresponds to at least one of the burners; At least one primary fuel main pipe corresponding to each of the furnace chambers is arranged to provide fuel to all the burners corresponding to the furnace chamber; one of the primary fuel main pipes is communicated with at least one secondary fuel branch pipe arranged in parallel with each other, one of the secondary fuel branch pipes corresponds to at least one of the radiation furnace tube groups, and the secondary fuel branch pipe is used to provide fuel to the burners corresponding to the at least one of the radiation furnace tube groups corresponding thereto; For a single furnace chamber, a plurality of the secondary fuel branch pipes corresponding to a plurality of the radiation furnace tube groups arranged in the single furnace chamber are connected in parallel with each other, and then connected in series with the primary fuel main pipe corresponding to the single furnace chamber; A primary regulating valve is arranged on the primary fuel main pipe, and a secondary regulating valve is arranged on the secondary fuel branch pipe; A total heat value controller is further arranged on the primary fuel main pipe, the total heat value controller is used to monitor the actual total heat release after the fuel flowing through the primary fuel main pipe is combusted, and when the difference between the actual total heat release and the theoretical total heat is greater than a first preset value, the primary regulating valve is prompted to be adjusted, wherein the theoretical total heat refers to the total heat required to make the total average temperature at the outlet of each radiation furnace tube group in the furnace chamber corresponding to the primary fuel main pipe reach a preset total average temperature at the outlet of the radiation furnace tube; For a single radiation furnace tube group, a temperature measuring device is arranged at the outlet of each radiation furnace tube subgroup constituting the single radiation furnace tube group, one group temperature controller corresponding to the single radiation furnace tube group is arranged, the group temperature controller is connected with each of the temperature measuring devices, the group temperature controller is used to acquire the actual outlet average temperature of each radiation furnace tube subgroup from each of the temperature measuring devices, and when the difference between the actual outlet average temperature and a preset outlet average temperature is greater than a second preset value, the secondary regulating valve is prompted to be adjusted; One of the secondary fuel branch pipes corresponds to one of the radiation furnace tube groups, and is used to provide fuel to the burners corresponding to the radiation furnace tube group corresponding thereto; For a single furnace chamber, one total temperature controller corresponding to the single furnace chamber is arranged, the total temperature controller is connected with the group temperature controllers corresponding to a plurality of the radiation furnace tube groups arranged in the single furnace chamber; the total temperature controller is further connected with the total heat value controller on the primary fuel main pipe corresponding to the single furnace chamber. The first fuel main pipe is divided into a first sub main pipe and a second sub main pipe near one end of the combustor, the combustor is provided with a first spray gun and a second spray gun, for a single first fuel main pipe, the first sub main pipe is used to provide fuel for the first spray gun of all combustors arranged correspondingly with the single first fuel main pipe, and the second sub main pipe is used to provide fuel for the second spray gun of all combustors arranged correspondingly with the single first fuel main pipe; the first sub main pipe is communicated with at least one second fuel branch pipe arranged in parallel with each other, and the second sub main pipe is communicated with at least one second fuel branch pipe arranged in parallel with each other.

2. Cracking furnace according to claim 1, characterized in that For a single furnace, all combustors arranged at the bottom of the single furnace, all combustors arranged at the sidewall of the single furnace and all combustors arranged at the top of the single furnace are correspondingly arranged with a first fuel main pipe.

3. A method of controlling the outlet temperature of the tubes of a cracker furnace according to any one of claims 1-2, said cracker furnace having at least one furnace chamber, each of said furnace chambers housing a plurality of groups of radiant tubes, characterized in that, The method comprises: For a single furnace, the actual average outlet temperature of each radiation furnace pipe group in the single furnace is obtained by a temperature measuring device arranged at the outlet of each radiation furnace pipe group, and the actual total average outlet temperature of all radiation furnace pipe groups in the single furnace is determined according to the actual average outlet temperature of each radiation furnace pipe group. In the case that the difference between the actual total average outlet temperature and the preset total average outlet temperature is greater than a first preset value, the total flow of fuel flowing into the combustor corresponding to the single furnace is adjusted so that the difference between the actual total average outlet temperature and the preset total average outlet temperature is less than the first preset value. For a single radiation furnace pipe group, in the case that the difference between the actual average outlet temperature and the preset average outlet temperature is greater than a second preset value, the sub flow of fuel flowing into the combustor corresponding to the single radiation furnace pipe group is adjusted so that the difference between the actual average outlet temperature and the preset average outlet temperature is less than the second preset value. According to the actual total average outlet temperature, the actual total heat consumed by all radiation furnace pipe groups in the single furnace is determined, and in the case that the difference between the actual total heat and the theoretical total heat is greater than a third preset value, the total flow of fuel flowing into the combustor corresponding to the single furnace is adjusted so that the difference between the actual total heat and the theoretical total heat is less than the third preset value, wherein the theoretical total heat refers to the total heat required to make the total average outlet temperature of the furnace pipe of each radiation furnace pipe group in the single furnace reach the preset total average outlet temperature.

4. The method of claim 3, wherein, The actual total average outlet temperature of all radiation furnace pipe groups in the single furnace is determined according to the actual average outlet temperature of each radiation furnace pipe group, which comprises: The arithmetic mean of the actual average outlet temperature of each radiation furnace pipe group is determined as the actual total average outlet temperature.

Images