CN115875669A - Cracking furnace and furnace tube outlet temperature control method thereof - Google Patents

Abstract

The present disclosure relates to a cracking furnace and a furnace tube outlet temperature control method of the cracking furnace, in the cracking furnace, at least one primary fuel main tube is correspondingly arranged on a furnace chamber, one primary fuel main tube is communicated with at least one secondary fuel branch tube which is parallel to each other, one secondary fuel branch tube is corresponding to at least one radiation furnace tube big group in the furnace chamber and is used for providing fuel for a burner corresponding to the at least one radiation furnace tube big group corresponding to the primary fuel main tube, therefore, the control accuracy of the fuel flow flowing into the burner corresponding to each radiation furnace tube big group can be significantly improved by adjusting the fuel flow flowing through each secondary fuel branch tube, and the control accuracy of the furnace tube outlet average temperature of each radiation furnace tube big group is significantly improved.

Description

Cracking furnace and furnace tube outlet temperature control method thereof

Technical Field

The disclosure relates to the technical field of petrochemical industry, in particular to a cracking furnace and a furnace tube outlet temperature control method of the cracking furnace.

Background

In the related art, cracking furnaces are used for processing and cracking various types of cracking raw materials such as gas raw materials, light liquid raw materials, heavy liquid raw materials and the like. Because the cracking conditions of different types of cracking raw materials are different greatly, the cracking performance and the operating conditions of the cracking furnace need to be optimally designed based on the main cracking raw materials during the design. However, due to the diversity of cracking feedstocks, even a cracking furnace adapted for a particular type of cracking feedstock needs to be compatible with cracking other types of cracking feedstocks.

With the intensive research on the cracking principle, it is gradually recognized that high temperatures, short residence times and low hydrocarbon partial pressures contribute to an increase in cracking selectivity. However, in the actual control of the cracking furnace, because the configuration of the radiation furnace tubes of the cracking furnace is determined, under the condition that the feeding amount and the properties of the raw materials are not changed, the residence time of the cracking raw materials in the cracking furnace is basically unchanged, meanwhile, because the ratio of the cracking raw materials to the dilution steam is kept constant, the hydrocarbon partial pressure in the cracking furnace is also basically unchanged, and therefore, the cracking depths of different types of cracking raw materials are mainly controlled by adjusting the average temperature of the furnace tube outlets of the cracking furnace in the actual operation.

The existing cracking furnace indirectly regulates and controls the average temperature of the furnace tube outlet of each radiation furnace tube large group by regulating and controlling the raw material flow passing through each raw material pipeline and the total combustion flow passing through the side wall fuel main pipe and the bottom fuel main pipe.

Disclosure of Invention

The invention aims to solve the problem that the conventional cracking furnace cannot accurately control the average temperature of the outlet of a furnace tube, and provides a cracking furnace and a method for controlling the temperature of the outlet of the furnace tube of the cracking furnace.

In order to achieve the above object, the present disclosure provides a cracking furnace, which includes a convection section, a radiation section and a plurality of burners, wherein the radiation section has at least one hearth, a plurality of radiation furnace tube large groups are arranged in each hearth, each radiation furnace tube large group is composed of at least one radiation furnace tube small group, and each radiation furnace tube large group is communicated with the convection section through a cross tube; the burner is arranged at least one of the bottom, the side wall or the top of each hearth, and the burner is arranged at a position such that one radiant furnace tube corresponds to at least one burner in a large group;

at least one primary fuel main pipe is arranged corresponding to one hearth, and the primary fuel main pipes are used for providing fuel for all combustors corresponding to the hearths; one primary fuel main pipe is communicated 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 pipe large group, and the secondary fuel branch pipe is used for supplying fuel to a combustor corresponding to at least one radiation furnace pipe large group corresponding to the secondary fuel branch pipe; aiming at a single hearth, after a plurality of secondary fuel branch pipes corresponding to a plurality of radiation furnace pipe large groups arranged in the single hearth are mutually connected in parallel, the secondary fuel branch pipes are connected with the primary fuel main pipe corresponding to the single hearth in series or in other modes.

Optionally, one of the secondary fuel legs corresponds to one of the radiant coils of the larger group and is adapted to provide fuel to the burner corresponding to the corresponding radiant coil of the larger group.

Optionally, for a single furnace, one primary fuel main pipe is respectively and correspondingly arranged on all burners arranged at the bottom of the single furnace, all burners arranged on the side wall of the single furnace, and all burners arranged at the top of the single furnace.

Optionally, one end of the primary fuel main pipe, which is close to the combustor, is divided into a first secondary main pipe and a second secondary main pipe, the combustor has a primary spray gun and a secondary spray gun, and for a single primary fuel main pipe, the first secondary main pipe is used for supplying fuel to the primary spray guns of all the combustors arranged corresponding to the single primary fuel main pipe, and the second secondary main pipe is used for supplying fuel to the secondary spray guns of all the combustors arranged corresponding to the single primary fuel main pipe; the first sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other, and the second sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other.

Optionally, the primary fuel main pipe is provided with a primary regulating valve, and the secondary fuel branch pipe is provided with a secondary regulating valve.

Optionally, the primary fuel main pipe is further provided with a total heat value controller, and the total heat value controller is configured to monitor an actual total heat release amount after the fuel flowing through the primary fuel main pipe is combusted, and prompt the primary regulating valve to be regulated when a difference between the actual total heat release amount and a theoretical total heat amount is greater than a first preset value, where the theoretical total heat amount refers to a total heat amount required when a total average temperature of furnace tube outlets of each large group of radiating furnace tubes in a furnace chamber corresponding to the primary fuel main pipe reaches a preset total average temperature of furnace tube outlets.

Optionally, for a single large group of radiant furnace tubes, temperature measuring devices are arranged at furnace tube outlets of each small group of radiant furnace tubes forming the single large group of radiant furnace tubes, a group temperature controller is correspondingly arranged on the single large group of radiant furnace tubes, and the group temperature controllers are correspondingly connected with the temperature measuring devices;

aiming at a single hearth, the single hearth is correspondingly provided with a total temperature controller, the total temperature controller is correspondingly connected with the grouped temperature controllers corresponding to the plurality of radiation furnace tube large groups arranged in the single hearth, and the total temperature controller is also correspondingly connected with the total heat value controller on the primary fuel main pipe corresponding to the single hearth.

The present disclosure also provides a method for controlling the temperature of a furnace tube outlet of a cracking furnace, the cracking furnace having at least one hearth, a plurality of large groups of radiant furnace tubes being arranged in each hearth, the method comprising:

aiming at a single hearth, respectively obtaining the actual furnace tube outlet average temperature of each large group of the radiant furnace tubes in the single hearth through temperature measuring equipment arranged at the furnace tube outlets of each small group of the radiant furnace tubes, and determining the actual furnace tube outlet total average temperature of all the large groups of the radiant furnace tubes in the single hearth according to the actual furnace tube outlet average temperature;

when the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature is larger than a first preset value, adjusting the total flow of the fuel flowing into the burner corresponding to the single hearth so that the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature is smaller than the first preset value;

and aiming at a single large group of the radiation furnace tubes, under the condition that the difference between the actual average temperature of the outlet of the furnace tubes and the preset average temperature of the outlet of the furnace tubes is greater than a second preset value, adjusting the sub-flow of the fuel flowing into the burner corresponding to the single large group of the radiation furnace tubes so as to enable the difference between the actual average temperature of the outlet of the furnace tubes and the preset average temperature of the outlet of the furnace tubes to be smaller than the second preset value.

Optionally, the actual total heat consumed by all the large groups of radiant tubes in the single furnace is determined according to the actual total average furnace tube outlet temperature, and when the difference between the actual total heat and the theoretical total heat is greater than a third preset value, the total flow of the fuel flowing into the burner corresponding to the single furnace is adjusted so that the difference between the actual total heat and the theoretical total heat is smaller than the third preset value, wherein the theoretical total heat refers to the total heat required when the total average furnace tube outlet temperature of each large group of radiant tubes in the single furnace reaches the preset total furnace tube outlet temperature.

Optionally, at least one primary fuel main pipe is correspondingly arranged on one furnace chamber, and the primary fuel main pipe is used for providing fuel for the burners arranged in the furnace chamber, preferably, one primary fuel main pipe is correspondingly arranged on all the burners arranged at the bottom of the furnace chamber, all the burners arranged on the side wall of the furnace chamber, and all the burners arranged at the top of the furnace chamber;

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 arranged on the primary fuel main pipe.

Optionally, one primary fuel main pipe is communicated with a plurality of secondary fuel branch pipes which are mutually parallel, one secondary fuel branch pipe corresponds to at least one radiant furnace pipe large group, and the secondary fuel branch pipe is used for supplying fuel to a burner corresponding to at least one radiant furnace pipe large group corresponding to the secondary fuel branch pipe,

and adjusting the sub-flow of the fuel flowing into the combustor corresponding to the single large group of the radiation furnace tubes by adjusting a secondary adjusting valve arranged on the secondary fuel branch tube corresponding to the single large group of the radiation furnace tubes.

Optionally, the determining an actual outlet total average temperature of all the large groups of radiant furnace tubes in the single furnace according to the actual outlet average temperature of each furnace tube includes:

and determining the arithmetic mean value of the average temperature of the outlet of each actual furnace tube as the total average temperature of the outlet of the actual furnace tube.

Through the technical scheme, in the cracking furnace provided by the disclosure, at least one primary fuel main pipe is correspondingly arranged on one furnace chamber, one primary fuel main pipe is communicated 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 pipe large group in the furnace chamber and is used for providing fuel for the burner corresponding to the at least one radiation furnace pipe large group corresponding to the primary fuel main pipe, therefore, the control accuracy of the fuel flow flowing into the burner corresponding to each radiation furnace pipe large group can be remarkably improved by adjusting the fuel flow flowing through each secondary fuel branch pipe, and the control accuracy of the average temperature of the furnace pipe outlet of each radiation furnace pipe large group is remarkably improved.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 schematically illustrates a schematic structural view of a prior art cracking furnace;

FIG. 2 schematically illustrates a schematic structural view of a cracking furnace according to an embodiment of the disclosure;

FIG. 3 schematically illustrates a schematic structural view of another cracking furnace according to an embodiment of the disclosure;

fig. 4 schematically shows a structural schematic diagram of another cracking furnace according to an embodiment of the present disclosure.

Description of the reference numerals

1. Convection section 2 radiant section

3. Burner 4 hearth

5. 6 side wall fuel main pipe of radiation furnace tube large group

7. Bottom fuel main 8 side wall regulating valve

9. Bottom regulating valve 10 cross pipe

11. Primary fuel main 12 secondary fuel branch

13. 14 two-stage regulating valves of first-stage regulating valve

15. Total heat value controller 16 temperature measuring equipment

17. Group temperature controller 18 general temperature controller

Detailed Description

The following detailed description of the embodiments of the disclosure refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

Fig. 1 schematically shows a structural schematic diagram of a conventional cracking furnace, as shown in fig. 1, the conventional cracking furnace includes a convection section 1, a radiation section 2 and a plurality of burners 3, the radiation section has at least one hearth 4, a plurality of large groups 5 of radiation furnace tubes are arranged in each hearth 4, and the burners 3 are arranged on the side wall and the bottom of the hearth 4 and are used for providing heat for each large group 5 of radiation furnace tubes. Wherein the fuel supplied to the sidewall burners is supplied by a sidewall fuel header 6, the fuel supplied to the bottom burners is supplied by a bottom fuel header 7, the sidewall fuel header is provided with a sidewall regulating valve 8 for regulating the total flow of the fuel supplied to the sidewall burners, and the bottom fuel header is provided with a bottom regulating valve 9 for regulating the total flow of the fuel supplied to the bottom burners.

The inventor of the present disclosure finds that, in the cracking furnace shown in fig. 1, the fuel flow supplied to all the sidewall burners can be controlled only by one sidewall fuel header and the sidewall control valve thereof, and the fuel flow supplied to all the bottom burners can be controlled only by one bottom fuel header and the bottom regulating valve thereof, and this setting mode can realize the control of the total average temperature of the furnace tube outlets of all the large groups of radiant furnace tubes by adjusting the total fuel flow supplied to the sidewall burners and the bottom burners, but this setting mode is at least not suitable for the control of the average temperature of the furnace tube outlets under the following three working conditions:

(1) When all the large groups of the radiation furnace tubes are used for cracking the same cracking raw material, because the combustion conditions of the burners corresponding to the large groups of the radiation furnace tubes are possibly different, the average temperature of the furnace tube outlets of the large groups of the radiation furnace tubes is possibly greatly different, in order to reduce the difference, the flow of the raw material entering the large groups of the radiation furnace tubes is usually adjusted, so that the flow of the radiation furnace tubes of different large groups is different, the flow entering each small group is different, the cracking depth of the cracking raw material is different due to different residence time and the like among different groups, the radiation furnace tubes are further coked, the operation period of the cracking furnace is seriously influenced, and the normal operation of the device is influenced;

(2) When one cracking furnace is used for cracking multiple cracking raw materials at the same time, different radiation furnace tube large groups can be used for cracking different cracking raw materials, and because the cracking performance difference of different cracking raw materials is large, different furnace tube outlet average temperatures need to be set for the radiation furnace tube large groups for cracking different cracking raw materials so as to enable different cracking raw materials to have proper cracking depths;

(3) In practical application, in order to improve the on-line rate of the cracking furnace, it is often necessary to crack the cracking raw material in a large group of partial radiation furnace tubes, and to decoke in a large group of partial radiation furnace tubes, which requires different average furnace tube outlet temperatures to be set for the large group of the cracking side radiation furnace tubes and the large group of the decoking side radiation furnace tubes.

Therefore, the existing cracking furnace cannot realize the precise regulation and control of the average temperature of the furnace tube outlet of the large group of each radiation furnace tube under at least the three working conditions, and specifically, the existing cracking furnace cannot realize at least the following three requirements:

(1) Under the condition that all radiation furnace tube large groups are used for cracking the same cracking raw material and the flow is required to be the same, all the radiation furnace tube large groups are required to have the same average temperature of the furnace tube outlet;

(2) Under the condition that different radiation furnace tube large groups are used for cracking different cracking raw materials, the radiation furnace tube large groups for cracking the different cracking raw materials are required to have different average temperatures of furnace tube outlets;

(3) Under the conditions that a part of radiation furnace tube large groups are used for cracking raw materials and a part of radiation furnace tube large groups are used for decoking, the cracking side radiation furnace tube large groups and the decoking side radiation furnace tube large groups are required to have different furnace tube outlet average temperatures.

In order to solve the above problems, the present disclosure provides a cracking furnace.

Fig. 2 schematically illustrates a structural schematic diagram of a cracking furnace according to an embodiment of the present disclosure, and as shown in fig. 2, the cracking furnace may include a convection section 1, a radiant section 2 and a plurality of burners 3, the radiant section 2 has at least one hearth 4, a plurality of radiant furnace tube subgroups 5 are arranged in each hearth 4, each radiant furnace tube subgroup 5 is composed of at least one radiant furnace tube subgroup, and each radiant furnace tube subgroup 5 is communicated with the convection section 1 through a cross pipe 10; the burners 3 are arranged at least one of the bottom, the side wall or the top of each furnace 4 (in fig. 2, the burners 3 are arranged at the bottom of the furnace 4), and the burners 3 are arranged at positions such that one large group 5 of radiant tubes corresponds to at least one burner 3;

at least one primary fuel main pipe 11 is correspondingly arranged on one furnace 4, and the primary fuel main pipe 11 is used for supplying fuel to all the burners 3 corresponding to the furnace 4; one primary fuel main pipe 11 is communicated with at least one secondary fuel branch pipe 12 which is mutually parallel, one secondary fuel branch pipe 12 corresponds to at least one radiation furnace tube large group 5, and the secondary fuel branch pipe 12 is used for supplying fuel to the combustor 3 corresponding to the at least one radiation furnace tube large group 5 corresponding to the secondary fuel branch pipe 12; for a single furnace 4, after being connected in parallel with each other, a plurality of secondary fuel branch pipes 12 corresponding to a plurality of radiation furnace pipe large groups 5 arranged in the single furnace 4 are connected in parallel and/or in series with the primary fuel main pipe 11 corresponding to the single furnace 4.

In the disclosure, specifically, when the cracking furnace works, for a single furnace, fuel from a battery compartment first enters a corresponding primary fuel main pipe, then is distributed into secondary fuel branch pipes arranged in parallel corresponding to each radiant furnace tube large group according to actual needs, and finally is distributed from the secondary fuel branch pipes into each burner corresponding to each radiant furnace tube large group.

Through the present disclosure, at least one primary fuel main pipe is correspondingly arranged on one hearth, one primary fuel main pipe is communicated 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 large group in the hearth and is used for supplying fuel to the burner corresponding to the at least one radiation furnace tube large group corresponding to the primary fuel main pipe, therefore, the control accuracy of the fuel flow flowing into the burner corresponding to each radiation furnace tube large group can be significantly improved by adjusting the fuel flow flowing through each secondary fuel branch pipe, and the control accuracy of the furnace tube outlet average temperature of each radiation furnace tube large group is significantly improved.

In particular, the cracking furnace of the present disclosure has the following advantages:

(1) Under the condition that all radiation furnace tube large groups are used for cracking the same cracking raw material and the flow is ensured to be the same, the deviation of the average temperature of the furnace tube outlet of each radiation furnace tube large group approaches to zero by adjusting the fuel flow flowing through each secondary fuel branch tube, so that the long-period stable operation of the cracking furnace is facilitated, the service life of the radiation furnace tubes is prolonged, and the stability of the product quality is also facilitated to be improved;

(2) Under the condition that different radiation furnace tube large groups are used for cracking different cracking raw materials, the fuel flow flowing through each secondary fuel branch tube is adjusted, so that the radiation furnace tube large groups for cracking the different cracking raw materials have different average furnace tube outlet temperatures, and the different cracking raw materials can be ensured to keep proper cracking depth during cracking, thereby overcoming the influence of the grouped cracking of the different cracking raw materials on the cracking furnace, and realizing the maximization of the benefit of a target cracking product and the stable operation of the cracking furnace;

(3) Under the condition that a part of radiation furnace tube large groups are cracked and a part of radiation furnace tube large groups are decoked, the fuel flow flowing through each secondary fuel branch pipe is adjusted, so that the cracking side radiation furnace tube large groups and the decoking side radiation furnace tube large groups have different furnace tube outlet average temperatures, the independent decoking condition of the part of radiation furnace tube large groups is realized under the condition that the integral operation of the cracking furnace is not influenced, the online rate of the cracking furnace can be obviously improved, and the benefit maximization of the cracking furnace is realized.

In accordance with the present disclosure, to further improve the accuracy of controlling the average furnace outlet temperature of each radiant furnace tubular main group, preferably, one secondary fuel branch pipe 12 corresponds to one radiant furnace tubular main group 5 and is used to supply fuel to the burner 3 corresponding to the corresponding radiant furnace tubular main group 5.

According to the present disclosure, for a single furnace, all the burners disposed at the bottom of the single furnace, all the burners disposed on the side wall of the single furnace, and all the burners disposed at the top of the single furnace may be respectively disposed with one primary fuel main pipe.

According to the present disclosure, one end of the primary fuel main pipe close to the burner may be divided into a first secondary main pipe and a second secondary main pipe, the burner has a primary spray gun and a secondary spray gun, and for a single primary fuel main pipe, the first secondary main pipe is configured to provide fuel to the primary spray guns of all the burners disposed corresponding to the single primary fuel main pipe, and the second secondary main pipe is configured to provide fuel to the secondary spray guns of all the burners disposed corresponding to the single primary fuel main pipe; the first sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other, and the second sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other.

According to the present disclosure, in order to more conveniently realize the regulation of the fuel flow rate flowing through the primary fuel main pipe and the secondary fuel branch pipe, preferably, the primary fuel main pipe 11 may be provided with a primary regulating valve 13, and the secondary fuel branch pipe 12 may be provided with a secondary regulating valve 14.

According to the disclosure, the primary fuel main pipe 11 may further be provided with a total heat value controller 15, where the total heat value controller 15 is configured to monitor an actual total heat release amount after the fuel flowing through the primary fuel main pipe 11 is combusted, and prompt the primary regulating valve 13 to regulate when a difference between the actual total heat release amount and a theoretical total heat amount is greater than a first preset value, where the theoretical total heat amount is a total heat amount required when a total average temperature of furnace tube outlets of each of the large groups of radiant furnace tubes 5 in the furnace chamber 4 corresponding to the primary fuel main pipe 11 reaches a preset total average temperature of the furnace tube outlets.

In the disclosure, specifically, the primary fuel main pipe is used for providing fuels required for cracking the cracking raw materials for all the radiation furnace tube large groups in a single hearth, and after the fuels enter the combustor for combustion, the provided heat can enable the total average temperature of the furnace tube outlets of all the radiation furnace tube large groups in the single hearth to reach the preset total average temperature of the furnace tube outlets.

The furnace tube outlet total average temperature refers to the arithmetic average value of the furnace tube outlet average temperatures of all the radiation furnace tube large groups, the preset furnace tube outlet total average temperature can be set according to the types of the cracking raw materials in all the radiation furnace tube large groups, and the setting aims to ensure that the cracking raw materials in all the radiation furnace tube large groups have proper cracking depth.

According to the present disclosure, for a single large group 5 of radiant furnace tubes, the furnace tube outlets of the small groups of radiant furnace tubes constituting the single large group 5 of radiant furnace tubes are provided with temperature measuring devices 16, the single large group 5 of radiant furnace tubes is correspondingly provided with a grouped temperature controller 17, and the grouped temperature controller 17 is correspondingly connected with each temperature measuring device 16; aiming at a single furnace 4, a total temperature controller 18 is correspondingly arranged on the single furnace 4, the total temperature controller 18 is correspondingly connected with the grouping temperature controller 17 corresponding to a plurality of radiation furnace tube large groups arranged in the single furnace, and the total temperature controller 18 is also correspondingly connected with the total heat value controller 15 on the primary fuel main pipe 11 corresponding to the single furnace 4.

In the disclosure, in particular, the temperature measuring device is used for detecting the furnace tube outlet temperature of each radiation furnace tube subgroup; the grouping temperature controller is used for acquiring the furnace tube outlet temperature of each radiation furnace tube subgroup from each temperature measuring device, and determining the arithmetic mean value of the furnace tube outlet temperature of each radiation furnace tube subgroup as the furnace tube outlet mean temperature of the radiation furnace tube large group; the total temperature controller is used for acquiring the average temperature of the furnace tube outlets of the radiation furnace tube large groups from each grouping temperature controller, and determining the arithmetic average value of the average temperature of the furnace tube outlets of the radiation furnace tube large groups as the total average temperature of the furnace tube outlets of all the radiation furnace tube large groups in the single hearth; the total heat value controller is used for acquiring the total average temperature of the outlet of the furnace tube from the total temperature controller, and calculating the actual total heat release after the fuel flowing through the primary fuel main tube is combusted according to the total average temperature of the outlet of the furnace tube.

Fig. 3 schematically shows a schematic structural view of another cracking furnace according to an embodiment of the present disclosure, in which burners are disposed on the bottom and the side wall of a furnace, unlike fig. 2. Fig. 4 schematically shows a structural view of another cracking furnace according to an embodiment of the present disclosure, in which burners are disposed on a side wall of a furnace chamber, unlike fig. 2.

A second aspect of the present disclosure provides a furnace tube outlet temperature control method for a cracking furnace having at least one furnace chamber, a plurality of radiation furnace tube large groups being arranged in each furnace chamber, which may include operations S110 to S130.

In operation S110, for a single furnace, the actual average temperature of the furnace tube outlets of the large groups of radiation furnace tubes in the single furnace is respectively obtained through the temperature measuring devices arranged at the furnace tube outlets of the small groups of radiation furnace tubes, and the actual total average temperature of the furnace tube outlets of all the large groups of radiation furnace tubes in the single furnace is determined according to the actual average temperature of the furnace tube outlets.

In this disclosure, specifically, the method of obtaining the average temperature of the furnace tube outlet of each large group of radiant furnace tubes may be a common method in the field, and the method includes obtaining the furnace tube outlet temperature of each small group of furnace tubes by using a temperature measuring device that can pass through the furnace tube outlet of each small group of radiant furnace tubes, and then taking the arithmetic average value of the furnace tube outlet temperatures of each small group of furnace tubes as the average temperature of the furnace tube outlet of each large group of radiant furnace tubes.

Further, after obtaining the actual average temperature of the furnace tube outlets of each large group of radiant furnace tubes, an arithmetic average of the actual average temperature of the furnace tube outlets may be determined as the actual total average temperature of the furnace tube outlets.

Next, in operation S120, when the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature is greater than a first preset value, the total flow of the fuel flowing into the burner corresponding to the single furnace is adjusted so that the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature is smaller than the first preset value.

Optionally, the present disclosure may further include: and under the condition that the difference between the actual total heat and the theoretical total heat is larger than a third preset value, adjusting the total flow of the fuel flowing into the combustor corresponding to the single hearth so as to enable the difference between the actual total heat and the theoretical total heat to be smaller than the third preset value, wherein the theoretical total heat refers to the total heat required when the furnace tube outlet total average temperature of each radiant furnace tube large group in the single hearth reaches the preset furnace tube outlet total average temperature.

In the disclosure, specifically, at least one primary fuel main pipe may be correspondingly arranged on one furnace, and the primary fuel main pipe is used for providing fuel to the burners arranged in the furnace, and preferably, all the burners arranged at the bottom of the furnace, all the burners arranged on the side wall of the furnace, and all the burners arranged at the top of the furnace may be correspondingly provided with one primary fuel main pipe respectively; 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 arranged on the primary fuel main pipe.

Next, in operation S130, for a single large group of radiant furnace tubes, when a difference between the actual average temperature at the furnace tube outlet and the preset average temperature at the furnace tube outlet is greater than a second preset value, the sub-flow of the fuel flowing into the burner corresponding to the single large group of radiant furnace tubes is adjusted so that the difference between the actual average temperature at the furnace tube outlet and the preset average temperature at the furnace tube outlet is smaller than the second preset value.

In the present disclosure, specifically, one primary fuel main pipe is communicated with a plurality of secondary fuel branch pipes which are parallel to each other, one secondary fuel branch pipe corresponds to at least one large group of radiant tubes, the secondary fuel branch pipe is used for supplying fuel to the burner corresponding to the at least one large group of radiant tubes corresponding to the primary fuel main pipe, and the sub flow rate of the fuel flowing into the burner corresponding to the single large group of radiant tubes can be adjusted by adjusting a secondary adjusting valve arranged on the secondary fuel branch pipe corresponding to the single large group of radiant tubes.

The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims (12)

1. The cracking furnace is characterized by comprising a convection section, a radiation section and a plurality of burners, wherein the radiation section is provided with at least one hearth, a plurality of radiation furnace tube large groups are distributed in each hearth, each radiation furnace tube large group consists of at least one radiation furnace tube small group, and each radiation furnace tube large group is communicated with the convection section through a cross tube; the burner is arranged at least one of the bottom, the side wall or the top of each hearth, and the burner is arranged at a position that one radiant furnace tube corresponds to at least one burner in a large group;

at least one primary fuel main pipe is arranged corresponding to one hearth, and the primary fuel main pipes are used for providing fuel for all combustors corresponding to the hearths; one primary fuel main pipe is communicated 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 pipe large group, and the secondary fuel branch pipe is used for supplying fuel to a combustor corresponding to at least one radiation furnace pipe large group corresponding to the secondary fuel branch pipe; aiming at a single hearth, after a plurality of secondary fuel branch pipes corresponding to a plurality of radiation furnace pipe large groups arranged in the single hearth are connected in parallel with each other, the secondary fuel branch pipes are connected in series with a primary fuel main pipe corresponding to the single hearth.

2. The cracking furnace of claim 1, wherein one of the secondary fuel legs corresponds to one of the radiant coils of the larger group and is adapted to supply fuel to the burners corresponding to the corresponding radiant coils of the larger group.

3. The cracking furnace according to claim 1, wherein for a single furnace, one primary fuel main pipe is respectively disposed for all burners disposed at the bottom of the single furnace, all burners disposed at the side wall of the single furnace, and all burners disposed at the top of the single furnace.

4. The cracking furnace of claim 1, wherein the end of the primary fuel main adjacent to the burner is divided into a first sub-main and a second sub-main, the burner having primary lances and secondary lances, the first sub-main for a single primary fuel main for supplying fuel to the primary lances of all burners disposed in correspondence with the single primary fuel main, the second sub-main for supplying fuel to the secondary lances of all burners disposed in correspondence with the single primary fuel main; the first sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other, and the second sub-main pipe is communicated with at least one secondary fuel branch pipe which is parallel to each other.

5. The cracking furnace according to any one of claims 1 to 4, wherein the primary fuel main pipe is provided with a primary regulating valve, and the secondary fuel branch pipe is provided with a secondary regulating valve.

6. The cracking furnace of claim 2, wherein the primary fuel main pipe is further provided with a total heat value controller, and the total heat value controller is configured to monitor an actual total heat release amount after the fuel flowing through the primary fuel main pipe is combusted, and prompt the primary regulating valve to be adjusted when a difference between the actual total heat release amount and a theoretical total heat amount is greater than a first preset value, wherein the theoretical total heat amount is a total heat amount required when a total average temperature of furnace tube outlets of each radiation furnace tube large group in the furnace cavity corresponding to the primary fuel main pipe reaches a preset total average temperature of the furnace tube outlets.

7. The cracking furnace of claim 6,

aiming at a single large group of radiation furnace tubes, temperature measuring equipment is arranged at the furnace tube outlet of each small group of radiation furnace tubes forming the single large group of radiation furnace tubes, a grouped temperature controller is correspondingly arranged on the single large group of radiation furnace tubes, and the grouped temperature controllers are correspondingly connected with the temperature measuring equipment;

aiming at a single hearth, the single hearth is correspondingly provided with a total temperature controller, the total temperature controller is correspondingly connected with the grouped temperature controllers corresponding to a plurality of radiation furnace tube large groups arranged in the single hearth, and the total temperature controller is also correspondingly connected with the total heat value controller on the primary fuel main pipe corresponding to the single hearth.

8. A method of controlling the temperature of a furnace tube outlet of a cracking furnace, said cracking furnace having at least one hearth, a plurality of large groups of radiant furnace tubes being arranged in each of said hearths, the method comprising:

aiming at a single hearth, respectively obtaining the actual average temperature of the furnace tube outlets of all the large groups of the radiation furnace tubes in the single hearth through temperature measuring equipment arranged at the furnace tube outlets of all the small groups of the radiation furnace tubes, and determining the total average temperature of the actual furnace tube outlets of all the large groups of the radiation furnace tubes in the single hearth according to the actual average temperature of the furnace tube outlets;

under the condition that the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature is larger than a first preset value, adjusting the total flow of the fuel flowing into the combustor corresponding to the single hearth so as to enable the difference between the actual furnace tube outlet total average temperature and the preset furnace tube outlet total average temperature to be smaller than the first preset value;

and aiming at a single large group of the radiant furnace tubes, under the condition that the difference between the actual average temperature of the outlet of the furnace tubes and the preset average temperature of the outlet of the furnace tubes is greater than a second preset value, regulating the sub-flow of the fuel flowing into the burner corresponding to the single large group of the radiant furnace tubes so as to ensure that the difference between the actual average temperature of the outlet of the furnace tubes and the preset average temperature of the outlet of the furnace tubes is less than the second preset value.

9. The method according to claim 8, wherein an actual total heat quantity consumed by all the large groups of radiant tubes in the single furnace is determined according to the actual total average furnace tube outlet temperature, and when a difference between the actual total heat quantity and a theoretical total heat quantity is larger than a third preset value, a total flow quantity of the fuel flowing into the burner corresponding to the single furnace is adjusted so that the difference between the actual total heat quantity and the theoretical total heat quantity is smaller than the third preset value, wherein the theoretical total heat quantity is a total heat quantity required when the average furnace tube outlet temperature of the large groups of radiant tubes in the single furnace reaches a preset total furnace tube outlet temperature.

10. The method according to claim 8 or 9,

at least one primary fuel main pipe is correspondingly arranged on one hearth, the primary fuel main pipe is used for providing fuel for the burners arranged in the hearth, and preferably, all the burners arranged at the bottom of the hearth, all the burners arranged on the side wall of the hearth and all the burners arranged at the top of the hearth are correspondingly provided with one primary fuel main pipe respectively;

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 arranged on the primary fuel main pipe.

11. The method of claim 10,

one primary fuel main pipe is communicated with a plurality of secondary fuel branch pipes which are parallel to each other, one secondary fuel branch pipe corresponds to at least one radiation furnace pipe large group, the secondary fuel branch pipe is used for providing fuel for a burner corresponding to at least one radiation furnace pipe large group corresponding to the secondary fuel main pipe,

and adjusting the sub-flow of the fuel flowing into the combustor corresponding to the single large group of the radiation furnace tubes by adjusting a secondary adjusting valve arranged on the secondary fuel branch tube corresponding to the single large group of the radiation furnace tubes.

12. The method of claim 8, wherein said determining an actual overall average outlet temperature for all of said plurality of radiant tubes in said single furnace from said actual average furnace tube outlet temperatures comprises:

and determining the arithmetic mean value of the average temperature of the outlet of each actual furnace tube as the total average temperature of the outlet of the actual furnace tube.

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