Air and natural gas flow combined control system for combustion chamber of zinc rectifying furnace

Abstract

The invention discloses an air and natural gas flow combined control system for a combustion chamber of a zinc rectifying furnace, which comprises a PLC (Programmable Logic Controller), and an air flow control module and a natural gas flow control module which are connected with the PLC, the air flow control module comprises an air sensor assembly and an air flow adjusting assembly, and the air sensor assembly monitors the air flow of the main air pipeline and the air flow of the branch air pipelines and transmits air flow data to the PLC. According to the combined control system for the air flow and the natural gas flow of the combustion chamber of the zinc rectifying furnace, by monitoring the air flow and the natural gas flow of multiple points in real time, the real-time air-fuel ratio, the natural gas flow proportion of the branch natural gas pipelines and the air flow proportion of the branch air pipelines can be rapidly adjusted through the PLC, and the air flow and the natural gas flow of the combustion chamber of the zinc rectifying furnace are controlled. The combined precise control of air and natural gas flow in the combustion chamber is realized, so that complete combustion of gas in the furnace is promoted, and the combustion efficiency of natural gas is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical equipment, and in particular to a combined control system for air and natural gas flow in a combustion chamber of a tower zinc rectification furnace. Background Art

[0002] As a key equipment in the pyrometallurgical zinc smelting process, the tower zinc distillation furnace uses the principle of continuous fractionation to separate the impurity metals (mainly lead, iron, cadmium, etc.) in crude zinc according to the different boiling points of the metals to obtain refined zinc or 1-3 grade zinc. It has the advantages of high zinc purity, strong raw material adaptability, and the ability to enrich other metals at the same time. In the zinc distillation furnace, the combustion chamber is an important part, which is responsible for providing high temperature conditions to promote the evaporation of zinc in the crude zinc metal liquid and separate it from other impurity metals, thereby achieving the purpose of purifying zinc metal.

[0003] The existing tower zinc distillation furnace combustion chamber has problems such as an inappropriate ratio of inlet air flow to inlet natural gas flow (air-fuel ratio) and unreasonable flow ratio distribution of air ducts and natural gas ducts on different layers, which can easily cause incomplete combustion of natural gas in the combustion chamber and low natural gas combustion efficiency. In addition, it will also cause local high temperature problems in the furnace, which is not conducive to safe production. Summary of the invention

[0004] In view of the problems existing in the combustion chamber of a tower zinc distillation furnace, the present invention provides a combined control system for the air and natural gas flow rates in the combustion chamber of a tower zinc distillation furnace, which at least solves one problem existing in the prior art and has the characteristics of promoting the complete combustion of the gas in the furnace, improving the combustion efficiency of the natural gas and preventing the formation of local high-temperature points.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: adopting a combined control system of air and natural gas flow in a combustion chamber of a tower zinc rectification furnace, the combustion chamber of the zinc rectification furnace includes a combustion chamber, an air pipeline and a natural gas pipeline, including a PLC controller and an air flow control module and a natural gas flow control module connected to the PLC controller, the air pipeline includes a main air pipeline and a branch air pipeline, the air flow control module includes an air sensor component and an air flow adjustment component, the air sensor component monitors the air flow of the main air pipeline and the branch air pipeline and transmits the air flow data to the PLC controller, the natural gas pipeline includes a main natural gas pipeline and a branch natural gas pipeline, the natural gas flow control module includes a natural gas sensor component and a natural gas flow adjustment component, the natural gas sensor component monitors the natural gas flow of the main natural gas pipeline and the branch natural gas pipeline and transmits the natural gas flow data to the PLC controller, the PLC controller receives the air flow data and the natural gas flow data to obtain real-time air-fuel ratio, natural gas flow ratio and air flow ratio, and compares with the set target air-fuel ratio, target natural gas flow ratio and target air flow ratio to obtain air flow adjustment data and natural gas flow adjustment data, and generates air flow adjustment instructions and natural gas flow adjustment instructions respectively, and the air flow adjustment component and the natural gas flow adjustment component receive the instructions to adjust the air flow and the natural gas flow.

[0006] Furthermore, the branch air duct includes a first-layer air duct, a second-layer air duct and a third-layer air duct, the inlet ends of the first-layer air duct, the second-layer air duct and the third-layer air duct are respectively connected to the main air duct, and the outlet ends are connected to the combustion chamber, and a fan is provided in the main air duct. The branch natural gas pipeline includes a first-layer natural gas pipeline and a second-layer natural gas pipeline, the inlet ends of the first-layer natural gas pipeline and the second-layer natural gas pipeline are respectively connected to the main natural gas pipeline, and the outlet ends are connected to the combustion chamber.

[0007] Furthermore, the air sensor assembly includes a total air flow sensor, a first-layer air flow sensor, a second-layer air flow sensor and a third-layer air flow sensor; the air flow regulating assembly includes a first-layer air flow regulating valve, a second-layer air flow regulating valve and a third-layer air flow regulating valve, the total air flow sensor is arranged in the air main duct, the total air flow sensor monitors the air flow data in the air main duct and transmits the data to the PLC controller, the fan adjusts the flow rate of air entering the air main duct according to the instruction of the PLC controller; the first-layer air flow sensor and the first-layer air flow regulating valve are arranged in the first-layer air duct, the first-layer air flow sensor monitors the air flow data in the first-layer air duct and transmits the data to the PLC controller, the first-layer The air flow regulating valve adjusts the flow cross-section of the air in the first-layer air duct according to the instruction of the PLC controller; the second-layer air flow sensor and the second-layer air flow regulating valve are arranged in the second-layer air duct, the second-layer air flow sensor monitors the air flow data in the second-layer air duct and transmits the data to the PLC controller, and the second-layer air flow regulating valve adjusts the flow cross-section of the air in the second-layer air duct according to the instruction of the PLC controller; the third-layer air flow sensor and the third-layer air flow regulating valve are arranged in the third-layer air duct, the third-layer air flow sensor monitors the air flow data in the third-layer air duct and transmits the data to the PLC controller, and the third-layer air flow regulating valve adjusts the flow cross-section of the air in the third-layer air duct according to the instruction of the PLC controller.

[0008] Furthermore, the natural gas sensor assembly includes a natural gas total flow sensor, a first-layer natural gas flow sensor and a second-layer natural gas flow sensor; the natural gas flow regulating assembly includes a natural gas flow total regulating valve, a first-layer natural gas flow regulating valve and a second-layer natural gas flow regulating valve; the natural gas flow total regulating valve and the natural gas total flow sensor are arranged in the natural gas main pipeline; the natural gas total flow sensor monitors the natural gas flow data in the natural gas main pipeline and transmits the data to the PLC controller; the natural gas flow total regulating valve adjusts the flow cross-section of the natural gas in the natural gas main pipeline according to the instructions of the PLC controller; the first-layer natural gas flow sensor and the first-layer natural gas flow regulating valve are arranged in the first-layer natural gas pipeline; the first-layer natural gas flow sensor monitors the natural gas flow data in the first-layer natural gas pipeline and transmits the data to the PLC controller; the first-layer natural gas flow regulating valve adjusts the flow cross-section of the natural gas in the first-layer natural gas pipeline according to the instructions of the PLC controller; the second-layer natural gas flow regulating valve and the second-layer natural gas flow sensor are arranged in the second-layer natural gas pipeline; the second-layer natural gas flow sensor monitors the natural gas flow data in the second-layer natural gas pipeline and transmits the data to the PLC controller; the second-layer natural gas flow regulating valve adjusts the flow cross-section of the natural gas in the second-layer natural gas pipeline according to the instructions of the PLC controller.

[0009] Furthermore, the PLC controller has built-in settings for a target air-fuel ratio of air and natural gas, a target natural gas flow ratio of the branch natural gas pipeline flow, and a target air flow ratio of the branch air pipeline flow.

[0010] Furthermore, the target air-fuel ratio is set to 1.2:1, the target air flow ratio is set to 0.33:0.38:0.29, and the target natural gas flow ratio is set to 0.60:0.40.

[0011] Furthermore, the sampling times of the air sensor assembly and the natural gas sensor assembly are fed back through relative measurement errors. The flow measurement cycle is divided into two stages. The first stage is the relative measurement error calculation stage, and the second stage is the sampling times adjustment stage. The sampling times of the second stage are adjusted by the relative measurement error calculated in the first stage. After the sampling times adjustment of the second stage is completed, the flow data measured in this stage are calculated to obtain the final flow size.

[0012] Furthermore, the calculation formula of the relative measurement error is:

[0013]

[0014]

[0015]

[0016] τ c : relative measurement error;

[0017] The average error of the first stage measurement;

[0018] The average flow rate measured in the first stage;

[0019] q i : The flow rate of the ith sampling in the 20 samplings in the first stage, q min With q max are the minimum and maximum flow rates in the 20 samplings in the first stage;

[0020] q i ': The size of the i-th sampling flow rate in the 18 samplings except the minimum sampling flow rate and the maximum sampling flow rate in the first stage;

[0021] The calculation formula for the sampling adjustment times is:

[0022]

[0023] n: sampling adjustment times, which is rounded to an integer based on the calculation result. The maximum sampling adjustment times shall not exceed 240 times;

[0024] τ0: initial relative measurement error, τ0 is 0.05;

[0025] The final measured flow rate is calculated as:

[0026]

[0027] Final measured flow

[0028] q" i : The size of the i-th sampling flow in the sampling flow except the minimum sampling flow and the maximum sampling flow in the second stage.

[0029] Furthermore, the air-fuel ratio, natural gas flow ratio and air flow ratio control use a proportional scaling rate to provide feedback on the control adjustment time. The air-fuel ratio proportional scaling rate and the control adjustment time calculation formula are:

[0030] Q k =1-T k / T k0

[0031]

[0032] Q k : air-fuel ratio scaling rate;

[0033] T k : Air-fuel ratio control adjustment time;

[0034] T k0 : Initial adjustment time of air-fuel ratio, T k0 60 minutes;

[0035] R k1 : After the system adjusts the device for controlling the air-fuel ratio, the PLC controller initially calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor. During the control adjustment time, the PLC controller calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor every 10 minutes;

[0036] R k2:Before the system adjusts the air-fuel ratio, the PLC controller calculates the air-fuel ratio for the last time based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor. During the control adjustment time, the PLC controller calculates the air-fuel ratio for the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor every 10 minutes.

[0037] Furthermore, the scaling ratio of the branch natural gas pipeline flow ratio and the control adjustment time calculation formula are:

[0038] Q n =1-T n / T n0

[0039]

[0040] Q n : Scaling ratio of branch natural gas pipeline flow ratio;

[0041] T n : Control and adjustment time of branch natural gas pipeline flow ratio;

[0042] T n0 : Initial adjustment time of branch natural gas pipeline flow ratio, 120 minutes;

[0043] R n1 : After the system adjusts the device for controlling the flow ratio of the branch natural gas pipeline, the PLC controller calculates the flow ratio of the branch natural gas pipeline for the first time based on the flow data of the branch natural gas pipeline. During the control adjustment time, the PLC controller calculates the flow ratio of the branch natural gas pipeline once every 20 minutes;

[0044] R n2 : The branch natural gas pipeline flow ratio is the last time the PLC controller calculated the branch natural gas pipeline flow data before the system adjusted the branch natural gas pipeline flow ratio. During the control adjustment time, the PLC controller calculates the branch natural gas pipeline flow ratio once every 20 minutes.

[0045] In summary, the present invention is beneficial in that:

[0046] The combined control system of air and natural gas flow in the combustion chamber of the zinc distillation furnace of the present invention can monitor the air and natural gas flow at multiple locations in real time, and can quickly adjust the real-time air-fuel ratio, the natural gas flow ratio of the branch natural gas pipeline and the air flow ratio of the branch air pipeline through a PLC controller, thereby realizing combined and precise control of the air and natural gas flow in the combustion chamber, thereby promoting complete combustion of the gas in the furnace and improving the combustion efficiency of the natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic structural diagram of a combined control system for air and natural gas flow in a combustion chamber of a tower zinc rectification furnace of the present invention;

[0048] Figure 2 It is a schematic diagram of the device position of the present invention;

[0049] Figure 3 It is a schematic diagram of the structure of the monitoring section l1, the monitoring section c1 and the outer wall of the tower tray in the combustion chamber of the present invention;

[0050] Figure 4 It is a temperature distribution cloud diagram of the combustion chamber monitoring section l1 at different air-fuel ratios of the present invention;

[0051] Figure 5 The temperature distribution cloud diagram of the outer wall of the tower plate at different air-fuel ratios of the present invention;

[0052] Figure 6 The graph is a variation curve of the average furnace temperature and the average heat flux density of the outer wall of the tower plate at different air-fuel ratios of the present invention.

[0053] Figure 7 It is a temperature distribution cloud diagram of the combustion chamber monitoring section l1 when the flow ratio of the branch air duct of the present invention is different;

[0054] Figure 8 The temperature distribution cloud diagram of the outer wall surface of the tower tray when the flow ratio of the branch air duct of the present invention is different;

[0055] Figure 9a The average heat flux density variation curve of the outer wall of the tower tray when the flow ratio of the branch air duct of the present invention is different;

[0056] Figure 9b The average temperature variation curve of the outer wall of the tower tray when the flow ratio of the branch air duct of the present invention is different;

[0057] Fig.10 The total heat variation curve of natural gas combustion in the combustion chamber when the flow ratio of the branch air duct is different according to the present invention;

[0058] Fig.11 It is the velocity vector diagram of the cross section c1 of the combustion chamber when the flow ratios of the branch natural gas pipeline of the present invention are different;

[0059] Fig.12 It is a temperature distribution cloud diagram of the combustion chamber monitoring section l1 when the flow ratio of the branch natural gas pipeline of the present invention is different;

[0060] Fig.13 The cloud diagram of the temperature distribution on the outer wall of the tower plate when the flow ratios of the branch natural gas pipelines of the present invention are different;

[0061] Fig.14a The overall average heat flux density variation curve of the outer wall of the tower tray when the flow ratio of the branch natural gas pipeline of the present invention is different;

[0062] Fig.14b The total heat transfer curve of the outer wall of the tower plate when the flow ratio of the branch natural gas pipeline of the present invention is different;

[0063] Fig.15a The average heat flux density variation curve diagram of the upper and lower parts of the outer wall of the tower plate when the flow ratio of the branch natural gas pipeline of the present invention is different;

[0064] Fig.15b It is a curve diagram of the local average temperature variation of the upper and lower parts of the outer wall of the tower plate when the flow ratios of the branch natural gas pipeline of the present invention are different.

[0065] Figure numerals: combustion chamber 1, air duct 2, natural gas pipeline 3, main air duct 20, first-layer air duct 21, second-layer air duct 22, third-layer air duct 23, fan 201, main natural gas pipeline 30, first-layer natural gas pipeline 31, second-layer natural gas pipeline 32, total air flow sensor 40, first-layer air flow sensor 41, second-layer air flow sensor 42, third-layer air flow sensor 43, first-layer air flow regulating valve 44, second-layer air flow regulating valve 45, third-layer air flow regulating valve 46, total natural gas flow regulating valve 50, total natural gas flow sensor 51, first-layer natural gas flow sensor 52, first-layer natural gas flow regulating valve 53, second-layer natural gas flow sensor 54, second-layer natural gas flow regulating valve 55. DETAILED DESCRIPTION

[0066] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0067] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0068] All directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, horizontal, vertical...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0069] Due to installation errors and other reasons, the parallel relationship referred to in the embodiments of the present invention may actually be an approximately parallel relationship, and the vertical relationship may actually be an approximately vertical relationship.

[0070] Embodiment 1:

[0071] like Figure 1-Figure 2 As shown, an air and natural gas flow joint control system of a zinc distillation furnace combustion chamber of the present invention, the zinc distillation furnace combustion chamber includes a combustion chamber 1, an air duct 2 and a natural gas pipeline 3, the joint control system includes an air flow control module, a natural gas flow control module and a PLC controller, the air flow control module is arranged in the air duct 2, the natural gas flow control module is arranged in the natural gas pipeline 3, the air flow control module and the natural gas flow control module are respectively connected to the PLC controller, the air flow control module and the PLC controller monitor and control the air flow of the air duct 2, and the natural gas flow control module and the PLC controller monitor and control the natural gas flow of the natural gas pipeline 3.

[0072] The air duct 2 includes an air main duct 20 and branch air ducts, the branch air ducts include a first-layer air duct 21, a second-layer air duct 22 and a third-layer air duct 23, the inlet ends of the first-layer air duct 21, the second-layer air duct 22 and the third-layer air duct 23 are respectively connected to the air main duct 20, and the outlet ends are connected to the combustion chamber 1, and a fan 201 is arranged in the air main duct 20; air is drawn in by the fan 201, and passes through the air main duct 20 and the first-layer air duct 21, the second-layer air duct 22 and the third-layer air duct 23 into the combustion chamber 1; the natural gas pipeline 3 includes a natural gas main duct 30 and branch natural gas pipelines, the branch natural gas pipelines include a first-layer natural gas pipeline 31 and a second-layer natural gas pipeline 32, the inlet ends of the first-layer natural gas pipeline 31 and the second-layer natural gas pipeline 32 are respectively connected to the natural gas main duct 30, and the outlet ends are connected to the combustion chamber 1, and natural gas passes through the natural gas main duct 30 and the first-layer natural gas pipeline 31 and the second-layer natural gas pipeline 32 into the combustion chamber 1.

[0073] The air flow control module includes an air sensor component and an air flow regulating component. The air sensor component is used to monitor the air flow in the air duct 2 , and the air flow regulating component is used to regulate the air flow in the air duct 2 .

[0074] The air sensor assembly includes a total air flow sensor 40, a first-layer air flow sensor 41, a second-layer air flow sensor 42 and a third-layer air flow sensor 43; the air flow regulating assembly includes a first-layer air flow regulating valve 44, a second-layer air flow regulating valve 45 and a third-layer air flow regulating valve 46, and the first-layer air flow sensor 41, the second-layer air flow sensor 42, the third-layer air flow sensor 43, the first-layer air flow regulating valve 44, the second-layer air flow regulating valve 45 and the third-layer air flow regulating valve 46 are respectively connected to the PLC controller.

[0075] The total air flow sensor 40 is arranged in the air main duct 20, and the total air flow sensor 40 monitors the air flow data in the air main duct 20 and transmits the data to the PLC controller, and the fan adjusts the flow rate of air entering the air main duct 20 according to the instruction of the PLC controller; the first-layer air flow sensor 41 and the first-layer air flow regulating valve 44 are arranged in the first-layer air duct 21, and the first-layer air flow sensor 41 monitors the air flow data in the first-layer air duct 21 and transmits the data to the PLC controller, and the first-layer air flow regulating valve 44 adjusts the flow cross-section of the air in the first-layer air duct 21 according to the instruction of the PLC controller; the second-layer air flow sensor 42 and the second The second-layer air flow regulating valve 45 is arranged on the second-layer air duct 22, the second-layer air flow sensor 42 monitors the air flow data in the second-layer air duct 22 and transmits the data to the PLC controller, and the second-layer air flow regulating valve 45 adjusts the flow cross-section of the air in the second-layer air duct 22 according to the instruction of the PLC controller; the third-layer air flow sensor 43 and the third-layer air flow regulating valve 46 are arranged on the third-layer air duct 23, the third-layer air flow sensor 43 monitors the air flow data in the third-layer air duct 23 and transmits the data to the PLC controller, and the third-layer air flow regulating valve 46 adjusts the flow cross-section of the air in the third-layer air duct 23 according to the instruction of the PLC controller.

[0076] The air flow regulating component of this embodiment is not limited to the regulating valve, and other devices that can control the opening of the air duct can also be used.

[0077] The natural gas flow control module includes a natural gas sensor component and a natural gas flow regulating component. The natural gas sensor component and the natural gas flow regulating component are respectively connected to the PLC controller. The natural gas sensor component includes a natural gas total flow sensor 51, a first-layer natural gas flow sensor 52 and a second-layer natural gas flow sensor 54. The natural gas flow regulating component includes a natural gas flow total regulating valve 50, a first-layer natural gas flow regulating valve 53 and a second-layer natural gas flow regulating valve 55. The natural gas flow total regulating valve 50 and the natural gas total flow sensor 51 are arranged in the natural gas main pipeline 30. The natural gas total flow sensor 51 monitors the natural gas flow data in the natural gas main pipeline 30 and transmits the data to the PLC controller. The natural gas flow total regulating valve 50 regulates the natural gas in the natural gas main pipeline 30 according to the instructions of the PLC controller. The first-layer natural gas flow sensor 52 and the first-layer natural gas flow regulating valve 53 are arranged on the first-layer natural gas pipeline 31. The first-layer natural gas flow sensor 52 monitors the natural gas flow data in the first-layer natural gas pipeline 31 and transmits the data to the PLC controller. The first-layer natural gas flow regulating valve 53 adjusts the flow cross-section of the natural gas in the first-layer natural gas pipeline 31 according to the instruction of the PLC controller. The second-layer natural gas flow regulating valve 55 and the second-layer natural gas flow sensor 54 are arranged on the second-layer natural gas pipeline 32. The second-layer natural gas flow sensor 54 monitors the natural gas flow data in the second-layer natural gas pipeline 32 and transmits the data to the PLC controller. The second-layer natural gas flow regulating valve 55 adjusts the flow cross-section of the natural gas in the second-layer natural gas pipeline 32 according to the instruction of the PLC controller.

[0078] The air flow regulating component of this embodiment is not limited to the regulating valve, and other devices that can control the opening of the air duct can also be used.

[0079] The PLC controller input terminal inputs the set target air-fuel ratio of air and natural gas, the target natural gas flow ratio of the branch natural gas pipeline flow, and the target air flow ratio of the branch air pipeline flow and transmits them to the PLC controller as the basis for subsequent air and natural gas flow data processing; the target air-fuel ratio is the ratio of the air flow in the air main pipeline 20 to the natural gas flow in the natural gas main pipeline 30; the target natural gas flow ratio is the ratio of the natural gas flow in the first-layer natural gas pipeline 31 and the second-layer natural gas pipeline 32; the target air flow ratio is the ratio of the air flow in the first-layer air pipeline 21, the second-layer air pipeline 22 and the third-layer air pipeline 23.

[0080] The target air-fuel ratio is set to 1.2:1, the target air flow ratio is set to 0.33:0.38:0.29, and the target natural gas flow ratio is set to 0.60:0.40.

[0081] Based on the above structure, the operation process of the combined control system of the flow of combustion chamber air and natural gas is as follows: air is drawn into the main air pipeline 20 by the fan, and enters the branch air pipeline after passing through the total air flow sensor 40; the air sensor component monitors the air flow data of the main air pipeline and the branch air pipeline and transmits the data to the PLC controller; natural gas is introduced into the main natural gas pipeline 30, and enters the branch natural gas pipelines respectively through the total natural gas flow sensor 51 and the natural gas flow main regulating valve 50; the natural gas sensor component monitors the natural gas flow data of the main natural gas pipeline and the branch natural gas pipeline respectively and transmits the data to the PLC controller; the PLC controller processes the received air flow data and natural gas flow data, obtains the real-time air-fuel ratio, the real-time natural gas flow ratio, and the air flow ratio, and compares them with the target air-fuel ratio, the target natural gas flow ratio, and the target air flow ratio respectively, obtains the adjustment data of the air inlet flow and the natural gas inlet flow, and sends the adjustment data to the fan 201 and the natural gas flow main regulating valve 50 respectively. 0 outputs control instructions, and the fan 201 and the natural gas flow total regulating valve 50 adjust the air inlet flow and the natural gas inlet flow according to the control instructions; obtains the adjustment data of the branch air pipeline flow, and outputs control instructions to the first-layer air flow regulating valve 44, the second-layer air flow regulating valve 45 and the third-layer air flow regulating valve 46 respectively, and the first-layer air flow regulating valve 44, the second-layer air flow regulating valve 45 and the third-layer air flow regulating valve 46 adjust the air flow of each layer of the air pipeline according to the control instructions; obtains the adjustment data of the branch natural gas pipeline flow, and outputs control instructions to the first-layer natural gas flow regulating valve 53 and the second-layer natural gas flow regulating valve 55 respectively, and the first-layer natural gas flow regulating valve 53 and the second-layer natural gas flow regulating valve 55 adjust the natural gas flow of each layer of the natural gas pipeline according to the control instructions, and the adjustment process is continuously circulated until the real-time air-fuel ratio is the set target air-fuel ratio, the natural gas flow ratio is the set target natural gas flow ratio, and the air flow ratio is the target air flow ratio.

[0082] like Figure 2 As shown, the position distribution of the combined control system is further shown, the fan 201 is arranged at the entrance of the main air pipeline 20, and the total air flow sensor 40 is arranged thereafter, and the air flow sensor of each layer is arranged after the air flow regulating valve; the total natural gas flow regulating valve 50 is arranged at the entrance of the main natural gas pipeline 30, and the total natural gas flow sensor 51 is arranged thereafter, and the natural gas flow sensor of each layer is arranged after the natural gas flow regulating valve.

[0083] like Figure 3 As shown, in order to facilitate the analysis of the distribution law of multi-physical fields in the combustion chamber of the tower zinc distillation furnace, a monitoring section l1 parallel to the east and west sides of the combustion chamber is cut in the combustion chamber, and a monitoring section c1 parallel to the bottom of the combustion chamber is cut. In addition, the outer wall of the tower plate is also used as the monitoring surface.

[0084] Regarding the effect of the air-fuel ratio on the combustion of natural gas in the combustion chamber, the following analysis is performed in this embodiment:

[0085] In this embodiment, commercial simulation software is used to analyze the combustion chamber operating conditions under different air-fuel ratios (the air-fuel ratio increases from 1.05:1 to 1.4:1, and 5 adjustment conditions are taken, namely 1.05:1, 1.145:1, 1.2:1, 1.3:1, and 1.4:1). At the same time, in order to evaluate the combustion effects of different air-fuel ratios, the combustion chamber temperature field, the average furnace temperature, and the average heat flux density of the tower plate are selected as evaluation indicators.

[0086] from Figure 4 It can be seen from (monitoring section l1) that as the air-fuel ratio increases, that is, as the amount of air gradually increases, the area of ​​the high-temperature zone in the combustion chamber l1 section first increases and then decreases, and the temperature of the local high-temperature point in the section also gradually increases, which indicates that the combustion chamber has undergone a process from insufficient air to excessive air. When the amount of air is insufficient, the combustion in the combustion chamber is incomplete, and the temperature of the monitoring section is low; as the amount of air increases, the temperature of the section gradually rises, and the area of ​​the high-temperature zone also increases; and when the air-fuel ratio continues to increase, the excess air increases the amount of flue gas, which increases the heat loss of the flue gas, causing the area of ​​the high-temperature zone in the section to gradually decrease, but sufficient air will still promote the formation of local high-temperature points. Among them, when the air-fuel ratio is 1.2:1, the area of ​​the high-temperature zone in the monitoring section is large, and no local high-temperature points are formed.

[0087] from Figure 5 (outer wall of the tray) shows that the high temperature area of ​​the tray mainly appears in the middle and upper part, which indicates that the natural gas in the middle and upper part of the combustion chamber burns more fully. As the air-fuel ratio increases, the high temperature area in the upper part of the tray gradually increases, while the high temperature area in the lower part increases first and then decreases. Combining the area of ​​the high temperature area of ​​the tray and the temperature level, it can be seen that the temperature field of the tray is at the target when the air-fuel ratio is 1.2:1.

[0088] from Figure 6It can be seen that with the increase of the air-fuel ratio, the average temperature of the combustion chamber first increases and then decreases, which is similar to the temperature field change law of the combustion chamber in the qualitative analysis. When the air-fuel ratio is 1.05:1, the average temperature of the flue gas in the combustion chamber is relatively low. As the amount of air increases, the degree of combustion of natural gas gradually increases, and the average temperature of the flue gas increases accordingly. When the air-fuel ratio continues to increase, the excess air increases the heat loss carried away by the flue gas, which causes the average temperature of the flue gas in the combustion chamber to drop rapidly. In addition, with the increase of the air-fuel ratio, the average heat flux density on the outer wall of the tower plate also shows a change law of first increasing and then decreasing. When the flue gas temperature in the combustion chamber rises, the heat transfer of the tower plate wall will increase accordingly, and vice versa. The heat flux density or heat transfer of the tower plate is closely related to the flue gas temperature. Combined with the change law of the average furnace temperature and the average heat flux density of the tower plate wall, it can be seen that there is a target air-fuel ratio in the combustion chamber of the zinc distillation furnace, so that the combustion heat transfer effect in the furnace reaches the target under the current structural and operating parameters. From Figure 7 From the intersection of the middle curve, it can be seen that the target air-fuel ratio is 1.2:1.

[0089] In summary, when the air-fuel ratio is 1.2:1, the combustion heat transfer effect of natural gas in the combustion chamber is the best, so the target air-fuel ratio is set to 1.2:1.

[0090] Regarding the influence of the flow ratio of the branch air duct in the embodiment on the combustion of natural gas in the combustion chamber, the embodiment performs the following analysis:

[0091] In this embodiment, commercial simulation software is used to analyze the combustion chamber operating conditions under different air flow ratios of branch air ducts (the air flow ratios of branch air ducts are set to 0.48:0.52:0, 0.39:0.43:0.18, 0.35:0.40:0.25, 0.33:0.38:0.29, and 0.32:0.36:0.32, respectively). At the same time, in order to evaluate the combustion effects of different air-fuel ratios, the combustion chamber temperature field, the average furnace temperature and the average heat flux density of the tower plate are selected as evaluation indicators.

[0092] from Figure 7 It can be seen from (monitoring section l1) that after the third-layer air duct 23 was put into use, the low-temperature area in the lower part of the combustion chamber was significantly eliminated, and a high-temperature area was formed near the third-layer air nozzle. The overall high-temperature area of ​​the monitoring section l4 also increased. In addition, as the proportion of the air flow of the third-layer air duct 23 increased, the low-temperature state at the top of the combustion chamber was significantly improved. The area of ​​the low-temperature area gradually decreased as the proportion of the air flow of the third-layer air duct 23 increased, but slightly increased when the air flow ratio of the third-layer air duct 23 was 0.32. The increase in the flue gas temperature in the combustion chamber is conducive to the heat transfer of the tower plate wall.

[0093] from Figure 8It can be seen from (outer wall of the tower tray) that the temperature distribution pattern of the outer wall of the tower tray is similar to that of the l4 monitoring section. The use of the third-layer air duct 23 has significantly improved the temperature distribution of the tower tray. As the proportion of the air flow of the third-layer air duct 23 increases, the low-temperature area in the middle and lower part of the tower tray gradually decreases, and the area of ​​the high-temperature area in the middle and upper part gradually increases.

[0094] As can be seen from Figure 9, as the air flow rate of the third-layer air duct 23 increases, the average heat flux density and the average temperature of the outer wall of the tower tray increase first and then decrease, and reach the maximum value when the air flow rate of the third-layer air duct 23 accounts for 0.29. Comprehensively compared, the temperature field of the outer wall of the tower tray reaches the target when the air flow rate of the third-layer air duct 23 accounts for 0.29.

[0095] from Fig.10 It can be seen that the variation pattern of the total reaction heat of the combustion chamber with the increase of the air flow ratio is similar to the average heat flux density or average temperature of the outer wall of the tower plate. With the increase of the air flow ratio of the third-layer air duct 23, it shows a pattern of first increasing and then decreasing, and reaches the maximum value when the air flow ratio of the third-layer air duct 23 is 0.29.

[0096] In summary, when the air flow ratio of the branch air duct is 0.33:0.38:0.29, the combustion condition of natural gas in the combustion chamber of the zinc distillation furnace can reach a better level, so the target natural gas flow ratio is set to 0.33:0.38:0.29.

[0097] Regarding the influence of the flow ratio of the branch natural gas pipeline in the embodiment on the natural gas combustion in the combustion chamber, the embodiment performs the following analysis:

[0098] In this embodiment, commercial simulation software is used to qualitatively and quantitatively analyze the combustion chamber operating conditions under four adjustment conditions (0.34:0.66, 0.50:0.50, 0.60:0.40, and 0.70:0.30) when the natural gas flow ratio of different branch natural gas pipeline flows increases from 0.34:0.66 to 0.7:0.3. At the same time, in order to evaluate the combustion effect of different natural gas flow ratios, the natural gas velocity field, temperature field, average heat flux density of the tower plate and the total heat transfer of the combustion chamber are selected as evaluation indicators.

[0099] from Fig.11It can be seen from (monitoring section c1) that as the proportion of natural gas flow in the first-layer natural gas pipeline 31 increases, the gas velocity at the mouth of the first-layer natural gas pipeline 31 increases significantly, among which the airflow velocity of the burner on the south side (i.e., the burner at the far inlet end) is slightly larger. However, the velocity distribution law in the entire c1 section is not much different. The airflow velocity in the north and south areas of the tower plate is relatively large, and is accompanied by a vortex structure. In addition, when the natural gas flow in the first-layer natural gas pipeline 31 increases, the overall average velocity of the c1 section increases slowly, which increases the degree of turbulence in the middle and upper part of the furnace, which is conducive to the mixed combustion of natural gas.

[0100] from Fig.12 It can be seen from (monitoring section l1) that the temperature distributions of the four adjustment conditions are similar, with only the high temperature area in the middle and lower part of the furnace being different. As the proportion of natural gas flow in the second-layer natural gas pipeline 32 decreases, the area of ​​the low temperature area in the middle and lower part decreases.

[0101] from Fig.13 (outer wall of the tower tray) It can be seen that increasing the natural gas flow ratio of the first-layer natural gas pipeline 31 increases the maximum temperature of the tower tray wall. By comparing different natural gas flow ratios, it can be seen that as the natural gas flow of the first-layer natural gas pipeline 31 increases, the high-temperature area of ​​the upper tower tray gradually increases, but the temperature of the lower tower tray decreases slightly. When the natural gas flow ratio of the second-layer natural gas pipeline 32 is 0.50, a high-temperature area can also be formed on the lower tower tray.

[0102] As can be seen from Figure 14, the average heat flux density and total heat transfer of the outer wall of the tower plate change in a similar manner with the natural gas flow rate ratio. Compared with the baseline operating condition (existing operating condition), the key parameters of the adjusted operating condition have been greatly improved. With the increase of the natural gas flow rate of the first-layer natural gas pipeline 31, the average heat flux density and total heat transfer of the tower plate increase slowly. When the natural gas flow rate ratio of the first-layer natural gas pipeline 31 reaches 0.6, the key parameters of the tower plate no longer increase.

[0103] As can be seen from Figure 15, the variation patterns of the average heat flux density and the average temperature in the local area of ​​the tower plate wall are generally similar. With the increase of the natural gas flow rate of the first-layer natural gas pipeline 31, the key parameters of the upper tower plate show a trend of first increasing and then decreasing, while the key parameters of the lower tower plate decrease slightly and then gradually stabilize.

[0104] In summary, increasing the proportion of natural gas flow in the first-layer natural gas pipeline 31 is beneficial to improving furnace conditions, while too large a proportion of flow will lead to poor improvement effects. The target natural gas flow ratio is 0.60:0.40 (adjusting operating condition Q3), and the natural gas flow in the first-layer natural gas pipeline 31 should not be too large, so the target natural gas flow ratio is set to 0.60:0.40.

[0105] Furthermore, in order to more accurately obtain the flow data of the above-mentioned pipelines that need to be monitored and reduce the impact of flow velocity fluctuations in the pipeline, the relative measurement error is used to provide feedback on the sampling times of the air sensor component and the natural gas sensor component. The system adjusts the sampling times of the air sensor component and the natural gas sensor component based on the relative measurement error. The flow measurement cycle can be divided into two stages. The first stage is the relative measurement error calculation stage, which lasts for 2 seconds and has 20 sampling times. The second stage is the sampling times adjustment stage, which lasts for 8 seconds. The sampling times of the second stage are adjusted according to the relative measurement error calculated in the first stage. When the relative measurement error exceeds the set threshold, the larger the relative measurement error, the more sampling times the flow sensor has. After the sampling times adjustment of the second stage is completed, the flow data measured in this stage is calculated to obtain the final flow size. The calculation formula for the relative measurement error, the sampling adjustment times, and the final measured flow rate can be:

[0106] ①Relative measurement error

[0107]

[0108]

[0109]

[0110] τ c : Relative measurement error.

[0111] The average error of the first stage measurement;

[0112] The average flow rate measured in the first stage;

[0113] q i : The flow rate of the ith sampling in the 20 samplings in the first stage, q min With q max are the minimum and maximum flow rates in the 20 samplings in the first stage;

[0114] q i ': The size of the i-th sampling flow rate in the 18 samplings except the minimum sampling flow rate and the maximum sampling flow rate in the first stage;

[0115] ②Sampling adjustment times

[0116]

[0117] n: sampling adjustment times, which is an integer based on the calculation result. The maximum sampling adjustment times shall not exceed 240 times.

[0118] τ0: initial relative measurement error, τ0 is 0.05;

[0119] ③Final measured flow

[0120]

[0121] Final measured flow

[0122] q i ”: The size of the i-th sampling flow in the sampling flow except the minimum sampling flow and the maximum sampling flow in the second stage;

[0123] Furthermore, in order to better realize the control of the above-mentioned air-fuel ratio, the natural gas flow ratio of the branch natural gas pipeline, and the air flow ratio of the branch air pipeline, and to reduce the control cost at the same time, the proportional scaling rate is used to provide feedback on the control adjustment time. The system determines whether to adjust the related devices for controlling the air-fuel ratio, the natural gas flow ratio of the branch natural gas pipeline, and the air flow ratio of the branch air pipeline based on the size of the proportional scaling rate. When the proportional scaling rate exceeds the set threshold, the control adjustment time is corrected. When the proportional scaling rate is larger, the control adjustment time is shorter. Therefore, the above-mentioned proportions can be adjusted in time to achieve accurate control. At the same time, three proportional scaling rates are set for the air-fuel ratio, the natural gas flow ratio of the branch natural gas pipeline, and the air flow ratio of the branch air pipeline, respectively, so as to achieve the respective adjustment of the above-mentioned proportions. The proportional scaling rates of the air-fuel ratio, the natural gas flow ratio of the branch natural gas pipeline, and the air flow ratio of the branch air pipeline, as well as the control adjustment time calculation formula can be:

[0124] ① Air-fuel ratio

[0125] Q k =1-T k / T k0

[0126]

[0127] Q k : air-fuel ratio scaling rate;

[0128] T k : Air-fuel ratio control adjustment time;

[0129] T k0 : Initial adjustment time of air-fuel ratio, T k0 60 minutes;

[0130] R k1: After the system adjusts the device for controlling the air-fuel ratio, the PLC controller initially calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor 40 and the natural gas flow data monitored by the total natural gas flow sensor 51. During the control adjustment time, the PLC controller calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor 40 and the natural gas flow data monitored by the total natural gas flow sensor 51 once every 10 minutes;

[0131] R k2 : Before the system adjusts the air-fuel ratio, the PLC controller calculates the air-fuel ratio for the last time based on the air flow data monitored by the total air flow sensor 40 and the natural gas flow data monitored by the total natural gas flow sensor 51. During the control adjustment time, the PLC controller calculates the air-fuel ratio for the air flow data monitored by the total air flow sensor 40 and the natural gas flow data monitored by the total natural gas flow sensor 51 once every 10 minutes.

[0132] ② Branch natural gas pipeline flow ratio

[0133] Q n =1-T n / T n0

[0134]

[0135] Q n : Scaling ratio of branch natural gas pipeline flow ratio;

[0136] T n : Control and adjustment time of branch natural gas pipeline flow ratio;

[0137] T n0 : Initial adjustment time of branch natural gas pipeline flow ratio, 120 minutes;

[0138] R n1 : After the system adjusts the device for controlling the flow ratio of the branch natural gas pipeline, the PLC controller calculates the flow ratio of the branch natural gas pipeline for the first time based on the flow data of the branch natural gas pipeline. During the control adjustment time, the PLC controller calculates the flow ratio of the branch natural gas pipeline once every 20 minutes;

[0139] R n2 : The branch natural gas pipeline flow ratio is the last time the PLC controller calculated the branch natural gas pipeline flow data before the system adjusted the branch natural gas pipeline flow ratio. During the control adjustment time, the PLC controller calculates the branch natural gas pipeline flow ratio once every 20 minutes.

[0140] ③Branch air duct flow ratio

[0141] Q a =1-T a / T a0

[0142]

[0143] Q a : Scaling ratio of branch air duct flow ratio;

[0144] T a : Control adjustment time of branch air duct flow ratio;

[0145] T a0 : Initial adjustment time of branch air duct flow ratio, 120 minutes;

[0146] R a12，1 : After the system adjusts the device for controlling the flow ratio of the branch air duct, the PLC controller calculates the flow ratio of the first and second layers of the branch air duct for the first time. During the control adjustment time, the PLC controller calculates the air-fuel ratio of the branch air duct flow data once every 20 minutes;

[0147] R a23，1 : After the system adjusts the device for controlling the flow ratio of the branch air duct, the PLC controller calculates the flow ratio of the second and third layers of the branch air duct for the first time. During the control adjustment time, the PLC controller calculates the air-fuel ratio of the branch air duct flow data once every 20 minutes;

[0148] R a12，2 : Before the system adjusts the branch air duct flow ratio, the first and second air duct flow ratios are calculated by the PLC controller for the last time. During the control adjustment time, the PLC controller calculates the air-fuel ratio of the branch air duct flow data every 20 minutes;

[0149] R a23，2 : Before the system adjusts the branch air duct flow ratio, the second and third air duct flow ratios are calculated by the PLC controller for the last time on the branch air duct flow data. During the control adjustment time, the PLC controller calculates the air-fuel ratio of the branch air duct flow data once every 20 minutes.

[0150] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Claims

1. A combined air and natural gas flow control system for a zinc distillation furnace combustion chamber, the zinc distillation furnace combustion chamber comprising a combustion chamber, an air pipeline and a natural gas pipeline, characterized in that: It includes a PLC controller and an air flow control module and a natural gas flow control module connected to the PLC controller. The air pipeline includes an air main pipeline and a branch air pipeline. The air flow control module includes an air sensor component and an air flow adjustment component. The air sensor component monitors the air flow of the air main pipeline and the branch air pipeline and transmits the air flow data to the PLC controller. The natural gas pipeline includes a natural gas main pipeline and a branch natural gas pipeline. The natural gas flow control module includes a natural gas sensor component and a natural gas flow adjustment component. The natural gas sensor component monitors the natural gas flow of the natural gas main pipeline and the branch natural gas pipeline and transmits the natural gas flow data to the PLC controller. The PLC controller receives the air flow data and the natural gas flow data to obtain the real-time air-fuel ratio, natural gas flow ratio and air flow ratio, and compares them with the set target air-fuel ratio, target natural gas flow ratio and target air flow ratio to obtain the air flow adjustment data and the natural gas flow adjustment data, and generates the air flow adjustment instruction and the natural gas flow adjustment instruction respectively. The air flow adjustment component and the natural gas flow adjustment component receive the instructions to adjust the air flow and the natural gas flow.

2. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 1, characterized in that: The branch air duct includes a first-layer air duct, a second-layer air duct and a third-layer air duct, the inlet ends of the first-layer air duct, the second-layer air duct and the third-layer air duct are respectively connected to the main air duct, and the outlet ends are connected to the combustion chamber. A fan is provided in the main air duct. The branch natural gas pipeline includes a first-layer natural gas pipeline and a second-layer natural gas pipeline, the inlet ends of the first-layer natural gas pipeline and the second-layer natural gas pipeline are respectively connected to the main natural gas pipeline, and the outlet ends are connected to the combustion chamber.

3. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 2, characterized in that: The air sensor assembly includes a total air flow sensor, a first-layer air flow sensor, a second-layer air flow sensor and a third-layer air flow sensor; the air flow regulating assembly includes a first-layer air flow regulating valve, a second-layer air flow regulating valve and a third-layer air flow regulating valve. The total air flow sensor is arranged in the main air duct, and the total air flow sensor monitors the air flow data in the main air duct and transmits the data to the PLC controller. The fan adjusts the flow rate of air entering the main air duct according to the instructions of the PLC controller; the first-layer air flow sensor and the first-layer air flow regulating valve are arranged in the first-layer air duct, and the first-layer air flow sensor monitors the air flow data in the first-layer air duct and transmits the data to the PLC controller. The air flow regulating valve adjusts the flow section of the air in the first-layer air duct according to the instruction of the PLC controller; the second-layer air flow sensor and the second-layer air flow regulating valve are arranged in the second-layer air duct, the second-layer air flow sensor monitors the air flow data in the second-layer air duct and transmits the data to the PLC controller, and the second-layer air flow regulating valve adjusts the flow section of the air in the second-layer air duct according to the instruction of the PLC controller; the third-layer air flow sensor and the third-layer air flow regulating valve are arranged in the third-layer air duct, the third-layer air flow sensor monitors the air flow data in the third-layer air duct and transmits the data to the PLC controller, and the third-layer air flow regulating valve adjusts the flow section of the air in the third-layer air duct according to the instruction of the PLC controller.

4. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 2, characterized in that: The natural gas sensor component includes a natural gas total flow sensor, a first-layer natural gas flow sensor and a second-layer natural gas flow sensor. The natural gas flow regulating component includes a natural gas flow total regulating valve, a first-layer natural gas flow regulating valve and a second-layer natural gas flow regulating valve. The natural gas flow total regulating valve and the natural gas total flow sensor are arranged in the natural gas main pipeline. The natural gas total flow sensor monitors the natural gas flow data in the natural gas main pipeline and transmits the data to the PLC controller. The natural gas flow total regulating valve adjusts the flow section of the natural gas in the natural gas main pipeline according to the instructions of the PLC controller. The first-layer natural gas flow sensor and the first-layer natural gas flow regulating valve are arranged in the first-layer natural gas pipeline. The first-layer natural gas flow sensor monitors the natural gas flow data in the first-layer natural gas pipeline and transmits the data to the PLC controller. The first-layer natural gas flow regulating valve adjusts the flow section of the natural gas in the first-layer natural gas pipeline according to the instructions of the PLC controller. The second-layer natural gas flow regulating valve and the second-layer natural gas flow sensor are arranged in the second-layer natural gas pipeline. The second-layer natural gas flow sensor monitors the natural gas flow data in the second-layer natural gas pipeline and transmits the data to the PLC controller. The second-layer natural gas flow regulating valve adjusts the flow section of the natural gas in the second-layer natural gas pipeline according to the instructions of the PLC controller.

5. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 1, characterized in that: The PLC controller has built-in settings for a target air-fuel ratio of air and natural gas, a target natural gas flow ratio of a branch natural gas pipeline flow, and a target air flow ratio of a branch air pipeline flow.

6. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 5, characterized in that: The target air-fuel ratio is set to 1.2:1, the target air flow ratio is set to 0.33:0.38:0.29, and the target natural gas flow ratio is set to 0.60:0.

40.

7. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 1, characterized in that: The sampling times of the air sensor assembly and the natural gas sensor assembly are fed back through relative measurement errors. The flow measurement cycle is divided into two stages. The first stage is the relative measurement error calculation stage, and the second stage is the sampling times adjustment stage. The sampling times of the second stage are adjusted by the relative measurement error calculated in the first stage. After the sampling times adjustment in the second stage is completed, the flow data measured in this stage are calculated to obtain the final flow size.

8. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 7, characterized in that: The calculation formula of the relative measurement error is: τ c : relative measurement error; The average error of the first stage measurement; The average flow rate measured in the first stage; q i : The flow rate of the ith sampling in the 20 samplings in the first stage, q min With q max are the minimum and maximum flow rates in the 20 samplings in the first stage; q' i : The size of the i-th sampling flow rate in the 18 samplings except the minimum sampling flow rate and the maximum sampling flow rate in the first stage; The calculation formula for the sampling adjustment times is: n: sampling adjustment times, rounded to an integer based on the calculation result, the maximum sampling adjustment times shall not exceed 240 times; τ0: initial relative measurement error, τ0 is 0.05; The final measured flow rate is calculated as: Final measured flow q" i : The size of the i-th sampling flow in the sampling flow except the minimum sampling flow and the maximum sampling flow in the second stage.

9. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 1, characterized in that: The air-fuel ratio, natural gas flow ratio and air flow ratio control use proportional scaling rate to feedback the control adjustment time. The proportional scaling rate of the air-fuel ratio and the control adjustment time calculation formula are: Q k =1-T k / T k0 Q k : air-fuel ratio scaling rate; T k : Air-fuel ratio control adjustment time; T k0 : Initial adjustment time of air-fuel ratio, T k0 60 minutes; R k1 : After the system adjusts the device for controlling the air-fuel ratio, the PLC controller initially calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor. During the control adjustment time, the PLC controller calculates the air-fuel ratio based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor every 10 minutes; R k2 :Before the system adjusts the air-fuel ratio, the PLC controller calculates the air-fuel ratio for the last time based on the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor. During the control adjustment time, the PLC controller calculates the air-fuel ratio for the air flow data monitored by the total air flow sensor and the natural gas flow data monitored by the total natural gas flow sensor every 10 minutes.

10. The air and natural gas flow rate combined control system for the combustion chamber of a zinc rectification furnace according to claim 9, characterized in that: The calculation formula of the scaling ratio and control adjustment time of the branch natural gas pipeline flow ratio is: Q n =1-T n / T n0 Q n : Scaling ratio of branch natural gas pipeline flow ratio; T n : Control and adjustment time of branch natural gas pipeline flow ratio; T n0 : Initial adjustment time of branch natural gas pipeline flow ratio, 120 minutes; R n1 : After the system adjusts the device for controlling the flow ratio of the branch natural gas pipeline, the PLC controller calculates the flow ratio of the branch natural gas pipeline for the first time based on the flow data of the branch natural gas pipeline. During the control adjustment time, the PLC controller calculates the flow ratio of the branch natural gas pipeline once every 20 minutes; R n2 : The branch natural gas pipeline flow ratio is the last time the PLC controller calculated the branch natural gas pipeline flow data before the system adjusted the branch natural gas pipeline flow ratio. During the control adjustment time, the PLC controller calculates the branch natural gas pipeline flow ratio once every 20 minutes.

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