阅读说明：本技术 一种烧结机烟气罩内温度控制系统及方法 (Temperature control system and method in flue gas hood of sintering machine ) 是由 吕庆 张巍 于 2020-07-07 设计创作，主要内容包括：本发明涉及一种烧结机烟气罩内温度控制系统及方法,包括台车、烟气罩、出风管道、逻辑控制器和计算机软件系统,所述的控制系统包括温度表Ⅰ、温度表Ⅱ、逻辑控制器和计算机软件系统,温度表Ⅰ设在烟气罩内进气调节阀下方,温度表Ⅱ设置在出风管道内,逻辑控制器与温度表Ⅰ、温度表Ⅱ和进气调节阀电性相连,计算机软件系统与逻辑控制器电性相连；所述的计算机软件系统包括出风温度函数拟合单元、罩内温度目标值计算单元和调节阀开度计算单元。本发明的优点是：通过调节阀的调节控制,结合多点检测及综合分析算法,实现了烟气罩内温度的精细化智能控制,利于烧结矿质量的提高,减少了循环烟气的热量流失,节能减排降耗。(The invention relates to a temperature control system and a method in a flue gas cover of a sintering machine, which comprises a trolley, a flue gas cover, an air outlet pipeline, a logic controller and a computer software system, wherein the control system comprises a thermometer I, a thermometer II, the logic controller and the computer software system; the computer software system comprises an air outlet temperature function fitting unit, a cover temperature target value calculating unit and an adjusting valve opening calculating unit. The invention has the advantages that: through the regulation control of the regulating valve and the combination of multi-point detection and comprehensive analysis algorithm, the refined intelligent control of the temperature in the flue gas hood is realized, the quality of sinter ore is improved, the heat loss of circulating flue gas is reduced, and the energy conservation, emission reduction and consumption reduction are realized.)

1. A temperature control system in a flue gas hood of a sintering machine comprises a trolley, a flue gas hood arranged above the trolley, an air outlet pipeline arranged below the trolley, a logic controller and a computer software system, and is characterized in that a plurality of groups of air inlet adjusting pipes are arranged at the top of the flue gas hood at equal intervals, an air inlet adjusting valve is arranged at the upper end of each air inlet adjusting pipe, a thermometer I is arranged below each group of air inlet adjusting pipes in the flue gas hood, a thermometer II is arranged in the air outlet pipeline, the thermometer I, the thermometer II and the air inlet adjusting valves are electrically connected with the logic controller, and the computer software system is electrically connected with the logic controller;

the computer software system comprises an air-out temperature function fitting unit, a cover internal temperature target value calculating unit and an adjusting valve opening calculating unit, wherein the input end of the air-out temperature function fitting unit is connected with the output end of the logic controller, the output end of the air-out temperature function fitting unit is connected with the input end of the cover internal temperature target value calculating unit, the output end of the cover internal temperature target value calculating unit is connected with the input end of the adjusting valve opening calculating unit, and the output end of the adjusting valve opening calculating unit is connected with the input end of the logic controller.

2. The system for controlling the temperature in the flue gas hood of the sintering machine according to claim 1, wherein every two inlet adjusting pipes are in one group, 4-6 groups are arranged in total, and the groups are arranged at the top of the flue gas hood at equal intervals.

3. The system for controlling the temperature in the flue gas hood of the sintering machine according to claim 1, wherein 10-15 air outlet pipelines are arranged.

4. The system for controlling the temperature in the flue gas hood of the sintering machine according to claim 1, wherein the outlet air temperature function fitting unit is used for calculating and determining an outlet air temperature function F (x); the cover temperature target value calculation unit is used for calculating and determining a target value T of a cover temperature table I_o(ii) a SaidThe regulating valve opening calculating unit is used for calculating and determining the opening H of the two air inlet regulating valves a and b in the combination_aAnd H_b。

Technical Field

The invention belongs to the technical field of industrial computer real-time control, and particularly relates to a system and a method for controlling the temperature in a flue gas hood of a sintering machine.

Background

The traditional sintering production has the characteristics of large waste gas amount, serious pollution load, various pollutants and the like, and the sintering flue gas circulation technology can well solve the problem. The flue gas circulation is a process of circularly recovering and recycling the flue gas discharged in the sintering process, and the amount of the circulating flue gas accounts for 20-30% of the total discharge amount. The technology not only reduces the total smoke discharge amount of sintering production and heat loss, but also enables the nitrogen oxides and the sulfur oxides to generate secondary chemical reaction in the smoke circulation process, converts part of harmful substances into harmless substances and reduces the discharge of the harmful substances. The flue gas hood of the sintering machine is arranged above the sintering machine trolley to form a closed space for flue gas to flow circularly, and is an important component of flue gas circulation. Under the action of the circulating fan, sintering flue gas enters the flue gas hood from the air inlet pipeline, then passes through sintering raw materials in the trolley to enter the air outlet pipeline, and finally flows back to the air inlet pipeline from part of the air outlet pipeline, so that a flue gas circulating process is completed. It is particularly important to maintain the temperature in the hood stable during the flue gas circulation: too low a temperature causes loss of precious circulating heat, increases consumption of fossil fuel in the sintering process, and also increases sintering pollution; too high temperature can cause the influence to the subsequent flue gas desulfurization of sintering, denitration workshop section, can directly destroy the production facility of subsequent workshop section when serious and cause economic loss difficult to retrieve. Therefore, the fine control of the temperature stability in the flue gas hood is a difficult problem to be solved urgently in sintering production.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a system and a method for controlling the temperature in a flue gas hood of a sintering machine.

The purpose of the invention is realized by the following technical scheme:

the invention discloses a temperature control system in a flue gas cover of a sintering machine, which comprises a trolley, a flue gas cover arranged above the trolley, an air outlet pipeline arranged below the trolley, a logic controller and a computer software system, and is characterized in that a plurality of groups of air inlet adjusting pipes are arranged at the top of the flue gas cover at equal intervals, an air inlet adjusting valve is arranged at the upper end of each air inlet adjusting pipe, a thermometer I is arranged below each group of air inlet adjusting pipes in the flue gas cover, a thermometer II is arranged in the air outlet pipeline, the thermometer I, the thermometer II and the air inlet adjusting valves are electrically connected with the logic controller, and the computer software system is electrically connected with the logic controller;

the computer software system comprises an air-out temperature function fitting unit, a cover internal temperature target value calculating unit and an adjusting valve opening calculating unit, wherein the input end of the air-out temperature function fitting unit is connected with the output end of the logic controller, the output end of the air-out temperature function fitting unit is connected with the input end of the cover internal temperature target value calculating unit, the output end of the cover internal temperature target value calculating unit is connected with the input end of the adjusting valve opening calculating unit, and the output end of the adjusting valve opening calculating unit is connected with the input end of the logic controller.

The outlet air temperature function fitting unit is used for calculating and determining an outlet air temperature function F (x); the cover temperature target value calculation unit is used for calculating and determining a target value T of a cover temperature table I_o(ii) a The regulating valve opening calculating unit is used for calculating and determining the opening H of the two air inlet regulating valves a and b in the combination_aAnd H_b。

Every two of the air inlet adjusting pipes are a group, 4-6 groups are arranged in total, and the groups are arranged at the top of the flue gas hood at equal intervals.

The air outlet pipeline is provided with 10-15 air outlet pipelines.

The invention discloses a method for controlling the temperature in a flue gas hood of a sintering machine, which is characterized in that a system for controlling the temperature in the flue gas hood of the sintering machine is adopted, and the method comprises the following steps:

step 1, calculating and determining an air outlet temperature function F (x) by an air outlet temperature function fitting unit of a computer software system

Step 1.1, establishing an air outlet temperature initial piecewise function T (x)

Setting the head of the trolley as an original point O, setting the horizontal length of the trolley away from the original point O as x, setting the air outlet pipelines into three groups according to the x length, setting the number of each group of pipelines into 3-6, and setting the initial piecewise functions of the air outlet temperature in the three groups of pipelines as T₁(x)、T₂(x) And T₃(x)，T₁(x)、T₂(x) And T₃(x) Determined by equation (1), equation (2), and equation (3), respectively:

T₁(x)＝C₁₁+C₁₂x+C₁₃x²(1)

T₂(x)＝C₂₁+C₂₂x+C₂₃x²(2)

T₃(x)＝C₃₁+C₃₂x+C₃₃x²(3)

wherein C is₁₁、C₁₂、C₁₃、C₂₁、C₂₂、C₂₃、C₃₁、C₃₂、C₃₃Is the undetermined coefficient;

step 1.2, determining an initial function T (x) of the outlet air temperature

The air outlet temperature initial function T (x) is formed by the sum of each group of air outlet temperature initial piecewise functions; selecting three thermometers II in each air outlet pipeline, substituting the measured value of the thermometers II and the horizontal length x value into a formula (1), a formula (2) and a formula (3), and solving a undetermined coefficient C₁₁、C₁₂、C₁₃、C₂₁、C₂₂、C₂₃、C₃₁、C₃₂、C₃₃Substituting into formula (1), formula (2) and formula (3) to obtain specific T₁(x)、T₂(x) And T₃(x) Then, the specific outlet air temperature initial function t (x) is determined by the formula (4):

T(x)＝T₁(x)+T₂(x)+T₃(x) (4)

step 1.3, determining the average value T of the outlet air temperature_a

Setting the horizontal distances of three air outlet pipelines as l, m and n, and the average value T of air outlet temperature_aDetermined by equation (5):

step 1.4, determining an adjusting coefficient K of an initial function of the air outlet temperature_T

The allowable range of the flue gas temperature of the air outlet outer net is set as (T)_min,T_max) Adjustment coefficient K of initial function of outlet air temperature_TDetermined by equation (6):

wherein, K_cThe temperature reduction coefficient of the pipeline is obtained;

step 1.5, determining an outlet air temperature function F (x)

Determining an air outlet temperature function according to the air outlet temperature initial function and the air outlet temperature initial function adjusting coefficient, wherein the air outlet temperature function F (x) is determined according to a formula (7):

F(x)＝K_TT(x) (7)

step 2, calculating and determining target value T of hood temperature table I by a hood temperature target value calculating unit of the computer software system_o

Step 2.1, determining the ratio K of the temperature in the cover to the air outlet temperature_r

Let the horizontal length from thermometer I to origin O be x_mThe measured value of the thermometer I is T_mTemperature ratio K of the thermometer I_rDetermined by equation (8):

step 2.2, determining target value T of temperature table I in the cover_o

The temperature ratio reflects the relationship between the temperature in the hood and the temperature of the outlet air in the same horizontal length, and the target value T of the temperature table I in the hood_oDetermined by equation (9):

T_o＝K_rF(x_m) (9)

step 3, calculating and determining the opening H of the two air inlet regulating valves a and b in the combination by a regulating valve opening calculating unit of a computer software system_aAnd H_b

Step 3.1, determining the temperature difference T of the thermometer I_△

Thermometer I temperature difference T_△Determined by equation (10):

T_△＝T_o-T_m(10)

wherein, T_oIs the target value of the thermometer I, T_mMeasured values of a thermometer I;

step 3.2, determining a regulating variable H of the combined air inlet regulating valve by adopting PID control_z

Setting the combined value of the opening degrees of the two air inlet regulating valves in each group as a regulating variable H_zSetting a temperature difference T_△Has a threshold value of T_wThen combining the regulating variable H of the intake regulating valve_zThere are two cases as follows:

a) when T is_△In the interval (-T)_w,+T_w) When other than H_zDetermined by equation (11):

b) when T is_△In the interval (-T)_w,+T_w) When the time is within, adopting PID to control H_z，H_zDetermined by equation (12):

wherein K_pTo proportional gain, T_tTo integrate the time constant, T_DIs a differential time constant;

step 3.3, determining the main control valve in the combined air inlet regulating valve

Setting the variation rate of the regulating variable of the combined air inlet regulating valve to be H_qtThe threshold value of the rate of change is H_△qtThen, the determination of the main control valve in the combined intake air regulating valve has two cases:

a) when H is present_qt>H_△qtIn the time, two air inlet regulating valves in the combination are both main control valves

b) When H is present_qt≤H_△qtWhen the air inlet adjusting valve in the combination is a main control valve, the selection is manually set;

step 3.4, determining the opening degree H of the valve a and the valve b of the two air inlet regulating valves in the combination_aAnd H_bThe opening degrees of the a valve and the b valve of the two air inlet regulating valves in the combination are respectively H_aAnd H_b，H_aAnd H_bDetermined by equation (13):

compared with the prior art, the invention has the advantages that:

according to the invention, the refined intelligent control of the temperature in the flue gas hood of the sintering machine is realized through the regulation control of the flue gas hood regulating valve and the combination of the PLC-based multipoint detection and comprehensive analysis algorithm, the heat loss of the circulating flue gas is reduced by the control mode, the consumption of fossil fuel is reduced, and the effects of energy conservation and emission reduction are achieved.

Drawings

FIG. 1 is a schematic diagram of a control system according to the present invention;

FIG. 2 is a schematic cross-sectional view of FIG. 1;

FIG. 3 is a block diagram of a computer software system architecture according to the present invention;

FIG. 4 is a flow chart of the logic algorithm calculation of the present invention.

Detailed Description

In order that the invention may be clearly, fully and completely described, it will be further described in the following detailed description of the preferred embodiments with reference to the accompanying drawings.

As shown in fig. 1 and 2, the temperature control system in the flue gas hood of the sintering machine of the invention comprises a trolley 1, a flue gas hood 2 arranged above the trolley 1, an air outlet pipeline 6 arranged below the trolley 1, a logic controller and a computer software system, and is characterized in that a plurality of groups of air inlet adjusting pipes 3 are arranged at the top of the flue gas hood 2 at equal intervals, an air inlet adjusting valve 4 is arranged at the upper end of each air inlet adjusting pipe 3, a thermometer i5 is arranged below each group of air inlet adjusting pipes in the flue gas hood 2, a thermometer ii 4 is arranged in the air outlet pipeline 6, the thermometers i5, ii 7 and 4 are electrically connected with the logic controller, and the computer software system is electrically connected with the logic controller;

as shown in fig. 3, the computer software system includes an outlet air temperature function fitting unit, a hood temperature target value calculating unit, and an adjusting valve opening calculating unit, wherein an input end of the outlet air temperature function fitting unit is connected to an output end of the logic controller, an output end of the outlet air temperature function fitting unit is connected to an input end of the hood temperature target value calculating unit, an output end of the hood temperature target value calculating unit is connected to an input end of the adjusting valve opening calculating unit, and an output end of the adjusting valve opening calculating unit is connected to an input end of the logic controller.

The outlet air temperature function fitting unit is used for calculating and determining an outlet air temperature function F (x); the cover temperature target value calculation unit is used for calculating and determining a target value T of a cover temperature table I_o(ii) a The regulating valve opening calculating unit is used for calculating and determining the opening H of the two air inlet regulating valves a and b in the combination_aAnd H_b。

The reaction modes of the sintering raw materials at different stages in the sintering process are different, the more the sintering raw materials are close to the tail part of the sintering machine along the traveling direction of the trolley 1, the more violent the reaction is, and the higher the temperature of the circulating flue gas passing through the materials is. A reasonable temperature control result in the flue gas cover 2 is to control the temperature of the flue gas in the flue gas cover 2 to a specific continuous function distribution curve along the traveling direction of the trolley 1. Based on the design of the air inlet adjusting valve 4, a continuous space can be divided into a plurality of sections of control areas, and the control areas are respectively and independently controlled to finally achieve the control target of the temperature continuous distribution curve in the cover.

The temperature control of each section of control area in the flue gas cover 2 is realized by a top air inlet adjusting valve 4. Because the smoke pressure in the smoke hood 2 is negative pressure during normal production, the external air can be pumped into the smoke hood 2 when the air inlet adjusting valve 4 is opened. Therefore, the larger the opening value of the air inlet adjusting valve 4 is, the lower the temperature of the area nearby in the flue gas hood 2 is; the smaller the opening value of the air inlet adjusting valve 4 is, the higher the temperature of the nearby area in the smoke cover 2 is. Through all air inlet governing valves 4 to on the flue gas cover 2 carry out the adjustment of different apertures, can realize the accurate control of temperature in the flue gas cover 2.

As shown in fig. 4, the method for controlling the temperature in the flue gas hood of the sintering machine according to the present invention is characterized in that the system for controlling the temperature in the flue gas hood of the sintering machine comprises the following steps:

step 1, calculating and determining an air outlet temperature function F (x) by an air outlet temperature function fitting unit of a computer software system

The temperature in the flue gas hood 2 is correlated with the temperature of the air outlet pipeline 6, and a function curve of the temperature of the air outlet pipeline 6 is found out firstly. Because the temperature value that temperature table II 7 detected in air-out pipeline 6 is discrete, consequently need come fitting out continuous air-out temperature function curve according to discrete detected value.

Step 1.1, establishing an air outlet temperature initial piecewise function T (x)

If the head of the trolley 1 is set as an original point O, the horizontal length from the original point O on the trolley 1 is x, the air outlet pipelines 6 are set into three groups according to the x length, the number of the three groups of pipelines is respectively 4, 6 and 4, and then the initial piecewise function T of the air outlet temperature in the three groups of pipelines₁(x)、T₂(x) And T₃(x) Determined by equation (1), equation (2), and equation (3), respectively:

T₁(x)＝C₁₁+C₁₂x+C₁₃x²(1)

T₂(x)＝C₂₁+C₂₂x+C₂₃x²(2)

T₃(x)＝C₃₁+C₃₂x+C₃₃x²(3)

wherein C is₁₁、C₁₂、C₁₃、C₂₁、C₂₂、C₂₃、C₃₁、C₃₂、C₃₃Is the undetermined coefficient.

Step 1.2, determining an initial function T (x) of the outlet air temperature

The outlet air temperature initial function T (x) is composed of the sum of all groups of outlet air temperature initial piecewise functions.

Selecting three thermometers II 7 in each air outlet pipeline 6, substituting the measured value and the horizontal length x value of the thermometers II 7 into a formula (1), a formula (2) and a formula (3), and solving a undetermined coefficient C₁₁、C₁₂、C₁₃、C₂₁、C₂₂、C₂₃、C₃₁、C₃₂、C₃₃Substituting into formula (1), formula (2) and formula (3) to obtain specific T₁(x)、T₂(x) And T₃(x) Then, the specific outlet air temperature initial function t (x) is determined by the formula (4):

T(x)＝T₁(x)+T₂(x)+T₃(x) (4)

step 1.3, determining the average value T of the outlet air temperature_a

The horizontal distances of three groups of air outlet pipelines 6 are respectively l, m and n, and the average value T of the air outlet temperature_aDetermined by equation (5):

step 1.4, determining an adjusting coefficient K of an initial function of the air outlet temperature_T

The allowable range of the flue gas temperature of the air outlet outer net is set as (T)_min,T_max) Adjustment coefficient K of initial function of outlet air temperature_TDetermined by equation (6):

wherein, K_cThe temperature reduction coefficient of the air outlet pipeline 6 is adopted;

step 1.5, determining an outlet air temperature function F (x)

Determining an air outlet temperature function according to the air outlet temperature initial function and the air outlet temperature initial function adjusting coefficient, wherein the air outlet temperature function F (x) is determined according to a formula (7):

F(x)＝K_TT(x) (7)

step 2, calculating and determining target value T of hood temperature table I by a hood temperature target value calculating unit of the computer software system_o

Step 2.1, determining the ratio K of the temperature in the cover to the air outlet temperature_r

Let the horizontal length from thermometer I5 to origin O be x_mThe measured value of the thermometer I5 is T_mTemperature ratio K of the temperature chart I5_rDetermined by equation (8):

step 2.2, determining target value T of temperature table I5 in the cover_o

The temperature ratio reflects the relationship between the temperature in the hood and the temperature of the outlet air in the same horizontal length, and the target value T of the temperature table I5 in the hood_oDetermined by equation (9):

T_o＝K_rF(x_m) (9)

step 3, calculating and determining the opening H of the two air inlet regulating valves a and b in the combination by a regulating valve opening calculating unit of a computer software system_aAnd H_b

Step 3.1, determining the temperature difference T of the thermometer I5_△

Thermometer I5 temperature difference T_△Determined by equation (10):

T_△＝T_o-T_m(10)

wherein, T_oIs the target value, T, of thermometer I5_mIs the measured value of thermometer I5;

step 3.2, determining the regulating variable H of the combined air inlet regulating valve 4 by adopting PID control_z

Setting the combined value of the opening degrees of the two air inlet regulating valves 4 in each group as a regulating variable H_zSetting a temperature difference T_△Has a threshold value of T_wThen the regulating variable H of the inlet regulating valve 4 is combined_zThere are two cases as follows:

a) when T is_△In the interval (-T)_w,+T_w) When other than H_zDetermined by equation (11):

b) when T is_△In the interval (-T)_w,+T_w) When the time is within, adopting PID to control H_z，H_zDetermined by equation (12):

wherein K_pTo proportional gain, T_tTo integrate the time constant, T_DIs a differential time constant;

step 3.3, determining the main control valve in the combined air inlet regulating valve 4

The control of the two inlet regulating valves 4 in the group takes different forms depending on the magnitude of the rate of change of the regulating variable. When the change rate of the regulating variable is large, the system sets the two air inlet regulating valves 4 as main control valves, and simultaneously regulates the two air inlet regulating valves 4 to increase the regulating capacity of the system; when the change rate of the regulating variable is small, the system sets one air inlet regulating valve 4 as a main control valve, and the air inlet regulating valve 4 is independently regulated to reduce the regulating capacity of the system.

The change rate of the regulating variable of the combined air inlet regulating valve 4 is set as H_qtThe threshold value of the rate of change is H_△qtThen, the determination of the main control valve in the combined intake air regulating valve 4 has two cases:

a) when H is present_qt>H_△qtWhen in use, the two air inlet regulating valves 4 in the combination are both main control valves;

b) when H is present_qt≤H_△qtWhen the air inlet adjusting valve 4 in the combination is a main control valve, the selection is manually set;

step 3.4, determining the opening degree H of the valve a and the valve b of the two air inlet regulating valves in the combination_aAnd H_b

The opening degrees of the a valve and the b valve of the two air inlet regulating valves in the combination are respectively H_aAnd H_b，H_aAnd H_bDetermined by equation (13):

the invention according to the present invention can be carried out in many different ways, and it is possible to obtain a plurality of different embodiments of the invention without any inventive work.