Air-coal mixed spraying automatic control system and method thereof
Technical field
The invention belongs to air-coal mixed spraying automatic control technology field, particularly a kind of air-coal mixed spraying automatic control system and method thereof are applicable in chain grate-rotary kiln-central cooler production technology the automatic monitoring and the Based Intelligent Control of coal gas and coal in the fuel system.
Background technology
After Pelletizing Plant, Capital Iron and Steel Co. utilizes and to move burnt emission coal gas project completion operation, Artificial Control fuel injection method, the fuel winding-up is divided into two parts, is auxilliary based on coal gas, coal, additional coal powder injection under promptly not enough at coal gas or the situation about can not satisfied temperature control requiring.The technological operation main points are: winding-up coal gas, a coal amount require process evenly, stable, two adjustment processes will be by a small margin, multifrequency time is adjusted, and avoids the big rise and big fall of temperature.The adjusting of coal gas amount adopts pneumatic control valve to regulate, and the adjusting of coal amount adopts the rotor scale to regulate.Transform preceding on-the-spot technological operation present situation by analyzing, on-the-spot fuel adjusting mode mainly has the following disadvantages:
The instability of 1) gas supply amount causes the frequent adjustment of fuel, influences the stable of temperature.Because pelletizing plant belongs to the coal gas terminal temperature difference, the gas supply amount can not get ensureing that the transient wave momentum is very big, for equilibrium temperature, needs frequently to adjust manually coal gas amount, coal amount.
2) temperature shows, exists certain hour at interval with current fuel control, after fluctuation appears in temperature, can not accurately know the fuel quantity of temperature fluctuation correspondence, and then accurately regulate targetedly.
3) influence the too many and real-time change of thermal balance factor, temperature fluctuation appears and after, can not judge reason, the degree that causes temperature fluctuation accurately, timely, and then judge the regulated quantity of given fuel.
4) for on-the-spot heat resisting exhauster, the frequent influence of regulating temperature fluctuation of one cold section air quantity of central cooler, the post can not be controlled in advance, can only be after fluctuation appear in temperature, and Compensation Regulation is followed in passive hysteresis, causes the fluctuation of temperature.
5) coal powder injection operating personnel's sense of responsibility has influenced the stable of temperature.Promptness, accuracy difference that the personnel of different quality adjust fuel, promptly human factor is the key that influences temperature stabilization, also is least that determine and the most masty problem.
In sum, artificial injected fuel control is subjected to all multifactor impacts, is difficult to reach temperature stabilization, controls ideal effect accurately.Therefore, have only, adopt advanced online accurate measurement rotor scale by technological means, utilization Intelligent Control Theory and method to fuel winding-up to control automatically be the critical path that addresses the above problem.
Summary of the invention
The object of the present invention is to provide a kind of air-coal mixed spraying automatic control system and method thereof, be with rotary kiln thermal balance Mathematical Modeling flexible Application in the air-coal mixed spraying automatic control system project, provide theoretical foundation by setting up Mathematical Modeling for software programming; The 2nd, propose to review one's lessons by oneself in real time positive theory.Review one's lessons by oneself positive theory in real time and solved in the control and increase along with the process system repair time, air leak rate of air curtain increases gradually, and the difficult problem of accuracy is calculated in influence, and domestic rotary kiln fuel automatic control system of the same type is had reference; The 3rd, present domestic pelletizing enterprise fuel injection system all adopts the single-fuel mode of coal or coal gas, and the air-coal mixed spraying that our factory adopts and coal, coal gas single-fuel mode are relatively, advantages such as having energy savings, reduce that coal gas effluxes, alleviates environmental protection pressure, cost is low, system is reliable, pellet quality is stable, minimizing ring formation, temperature stabilization, adjustment are accurate.
System of the present invention (as Fig. 1) comprises SPF rotor scale, flowmeter, thermocouple, Q18 electronic scale, laboratory, temperature-measuring gun, server, air-coal mixed spraying auto-control software; SPF rotor scale be installed in Pulverized Coal Bin and with coal spraying pipeline that burner is connected between, SPF rotor scale is connected with server by data wire; Flowmeter is installed between gas piping and the burner respectively, on the kiln head and tail cooling blower outlet conduit, on the combustion fan outlet conduit, on the roots blower outlet conduit, on the heat resisting exhauster inlet duct, flowmeter is connected with server by data wire; The Q18 electronic scale is installed on the green-ball travelling belt, and the Q18 electronic scale is connected with server by data wire; Thermocouple is installed on rotary kiln end and kiln tail, one cold section backheat airduct of the central cooler road respectively, on kiln hood and the kiln tail cooling air pipe outlet, thermocouple is connected with server by data wire; The calorific capacity of laboratory check coal gas, coal dust, the ferrous content of kiln hood ball, kiln tail ball; Temperature-measuring gun is measured the kiln surface temperature; The air-coal mixed spraying auto-control software is installed on the server.
Import the air-coal mixed spraying auto-control software in the server after the metering signal of SPF rotor scale, flowmeter, Q18 electronic scale, thermocouple is gathered automatically by data wire into, material index analysis data is by the air-coal mixed spraying auto-control software in the artificial input server.The air-coal mixed spraying auto-control software according to the permission use amount of coal gas, is controlled the output quantity of coal dust after carrying out calculation process according to the various data of collection in worksite automatically.
Autocontrol method of the present invention may further comprise the steps:
1, the laboratory is made regular check on the dry bulb that enters rotary kiln and is gone out the ferrous content of the kiln hood ball of rotary kiln, the calorific capacity of coal dust and the calorific capacity of coal gas; The kiln surface temperature is detected with temperature-measuring gun in the post.
2, the post manually to air-coal mixed spraying auto-control software typing kiln tail target temperature value, enter the dry bulb of rotary kiln and go out the ferrous content of the kiln hood ball of rotary kiln, the calorific capacity of coal dust and the calorific capacity of coal gas; The kiln surface temperature.
3, SPF rotor scale is gathered coal powder blowing amount automatically in real time and is uploaded the air-coal mixed spraying auto-control software; Flowmeter automatic real-time measurement gas flow, kiln head and tail cooling air flow, combustion air flow, Roots's wind flow, heat-resisting wind flow are uploaded the air-coal mixed spraying auto-control software; Thermocouple automatic real-time measurement kiln head and tail temperature, central cooler backheat wind-warm syndrome degree, kiln head and tail cooling air temperature are uploaded the air-coal mixed spraying auto-control software; The electronic scale automatic real-time measurement is gone into kiln ball ball amount and is uploaded the air-coal mixed spraying auto-control software.
4, the concrete handling process of air-coal mixed spraying auto-control software (as Fig. 3), utilize and gather the basic data that gets in first three step manually, automatically, according to thermal balance Mathematical Modeling (as Fig. 2), keep at material on the basis of weighing apparatus, enter the project of rotary kiln and be with the project overall thermal balance of heat expenditure rotary kiln to set up the rotary kiln thermal balance model according to the band heat, calculate the theoretical consumption figures of fuel.Wherein the rotary kiln heat receipt item comprises: go into the kiln spherical zone go into heat, ferrous in kiln oxidation heat liberation, hot blast bring heat, fuel combustion heat release into; Rotary kiln heat expenditure comprises: the kiln discharge spherical zone goes out that heat, flue gas are taken heat out of, kiln surface dissipated heat cooling air is taken heat out of.
5, system's correction factor calculates: air-coal mixed spraying auto-control software per minute calculating primary system correction factor, average system correction factor of calculating in per three minutes mixes gas, coal and sprays to control automatically to reach desired value.
At first obtain the thermally equilibrated initial temperature of rotary kiln, the material amount, ferrous content, air quantity, process system is because the real-time change of time between overhauls(TBO), its air leak rate of air curtain, ferrous content, temperature is also with maintenance real-time period variation (influenced by process system), simultaneously, the temporary derangement of on-the-spot process system, also can cause the related system preheating, the variation of roasting process, portion temperature, ferrous content, the unexpected short term variations of factors such as air leak rate of air curtain, preheating, roasting process heat absorption amount, amount of radiation is corresponding influenced and factor such as be difficult to determine, therefore, the natural fuel adjustment can't be strict consistent with theoretical result of calculation with the variation of time between overhauls(TBO), and the time between overhauls(TBO) is uncertain, burst accident uncertain, causing fuel to adjust error can't be by theoretical accurate Calculation, therefore be difficult to obtain accurate fuel and adjust data, at this difficult problem, the fuel winding-up has been proposed in real time from the notion of revising, promptly the theory error coefficient of adjusting first few minutes as natural fuel adjust in real time from correction factor, with in this minimizing process because of the time between overhauls(TBO), the systematic error that burst accident causes, rely on the feedback result data of online thermocouple carry out the fuel winding-up from Correction and Control.The control system per minute is according to current processing parameter: turnover rotary kiln material amount, turnover rotary kiln material temperature, turnover rotary kiln material ferrous oxide content, turnover rotary kiln air quantity, turnover rotary kiln wind-warm syndrome, kiln head and tail cooling air quantity, kiln head and tail cooling wind-warm syndrome, Fuel Consumption, calorific value of fuel, rotary kiln surface heat dissipation capacity, kiln tail actual temperature, kiln tail target temperature calculate system's correction factor of current accurate injected fuel adjustment amount.Calculated once theoretical accurately fuel adjustment amount, average system correction factor in per three minutes, the two product then is accurate actual accurately fuel adjustment amount from Correction and Control.
6, changed and deviation variation rate according to kiln tail actual temperature, kiln tail target temperature deviation in per three minutes, select concrete accurately from Correction and Control and fuzzy control rule, obtain revised theoretical winding-up amount, the coal gas amount is carried out discrete processes, and to obtain the coal dust output quantity (be to regulate coal dust herein, when using coal gas separately, obtain gas output), coal dust (coal gas) output quantity discrete processes compares with natural fuel winding-up amount and to obtain coal dust (coal gas) adjustment amount.
7, coal dust (coal gas) adjustment amount feedback SPF rotor scale frequency converter (pneumatic control valve of HP-F type gas, solid dual burner) is adjusted coal dust (coal gas) winding-up amount.
This project has realized the target control of rotary kiln temperature, has controlled automatically and stablize control, has reached optimization pellet roasting process, equilibrium temperature control, improves roasting efficient, has reduced purpose such as post labour intensity.
Effect of the present invention is:
1) solved the judgement that the artificial experience operation caused inaccurate, adjust problem untimely, the temperature stabilization rate variance.
2) control has reduced operator's labour intensity automatically, has improved efficiency.
3) solved the instantaneous temperature big ups and downs problem that fluctuates widely and cause of coal gas.
4) positive concept is reviewed one's lessons by oneself in creationary proposition, efficiently solves combustion system along with the maintenance production cycle prolongs, the problem that systematic error progressively increases.
5) because the raising of coal powder metering precision, coal gas is instantaneous when fluctuating widely, and can access accurately replenishing of coal dust, improves the kiln end temperature coefficient of stabilization, and the kiln end temperature fluctuation range reduces by 40%.
6) the kiln temperature coefficient of stabilization is improved, and localized hyperthermia's point is effectively controlled, and ring formation of rotary kiln is effectively improved, and kliner coating control is comparatively even.
Description of drawings
Fig. 1 is system component and connected mode figure thereof.
Fig. 2 is a rotary kiln thermal balance graph of a relation.
Fig. 3 is an air-coal mixed spraying control system logic chart.
Fig. 4 is the Fuzzy control system structure chart.
The specific embodiment
1, at the coal powder injection high building SPF rotor scale is installed and (is responsible for installation by producer, pelletizing plant cooperates), the back is installed carries out the adjustment of parameter jointly by producer and pelletizing plant, to the different freight spaces coal powder injection, the coal powder injection value of the metering coal powder injection value of SPF rotor scale and position in storehouse actual measurement compares, collect different coal powder injection precision curves according to different freight spaces, obtained position in storehouse and changed back coal powder injection metering detection data and adjust parameter, reach the expection requirement up to SPF rotor scale variable.
2, changing rotary kiln burner is HP-F type gas, solid dual burner, mixes the spray requirement when satisfying two kinds of fuel of bottle coal, and the self-regulating needs of coal gas.
3, lay signal cable and be used for transfer of data, import data such as real-time monitor temperature, air quantity, material amount, machine speed, coal gas amount, coal amount, ferrous amount, calorific value of fuel into PLC system and pelletizing plant's server, for control system provides the real time data parameter, make the production operation personnel can recognize the related data such as temperature, fuel of real-time change simultaneously
4, implement high building coal powder injection pipeline, 2 combustion fans, 2 winding-up fan improvements, by the two typhoon machines of realization (combustion-supporting, winding-up) simultaneously, use the transposing during separate unit blower fan (combustion-supporting, winding-up) uses separately.
5, set up thermal balance model, mix the spray systems soft ware and utilize the various coefficient correlations of field measurement: turnover bulb temperature rotary kiln surface coefficient of heat transfer, theory of computation coal amounts such as the rotary kiln cooling air coefficient of heat conduction, turnover hot blast specific heat capacity, oxidation ball specific heat capacity.
6, according to air-coal mixed spraying automatic control model establishment control software, the control output that becomes structure control and fuzzy control method realization fuel is adopted in programme-control.
The Fuzzy control system (see figure 4)
1) changing ec with deviation e, deviation is input quantity, and u is the output system controlling value.
2) domain and fuzzy language variable word set are determined.
The basic domain of rotary kiln temperature deviation e is [-2020], and the domain of discretization fuzzy language variable E is X={-6 ,-5 ,-4 ,-3 ,-2 ,-1,0,1,2,3,4,5, and 6}.The scale factor K 1=20/6=3.33 of deviation e.
The basic opinion of the ec of kiln end temperature deviation variation in like manner is [66]/min, and the domain of discretization fuzzy language variable EC is X={-6 ,-5 ,-4 ,-3 ,-2 ,-1,0,1,2,3,4,5, and 6}.Deviation changes the scale factor K 2=6/6=1 of ec.
Fuel controlled quentity controlled variable u, [1.41.4], the domain of discretization fuzzy language variable uc is X={-7 ,-6 ,-5 ,-4 ,-3 ,-2 ,-1,0,1,2,3,4,5,6, and 7}.K3=1.4/7=0.2
The linguistic variable word set of fetching Rotary Kiln Temperature deviation E for NB, NM, NS, NO, PO, PS, PM, PB}, the linguistic variable word set that deviation changes EC and rotary kiln fuel adjusting amount UC is { NB, NM, NS, O, PS, PM, PB}.
3) determining of membership function:
Discretization the fuzzy quantity of accurate amount and expression fuzzy language adopt the triangle membership function, see rotary kiln fuel winding-up amount fuzzy quantity assignment table 1, table 2, table 3:
Table 1 kiln temperature deviation fuzzy quantity assignment table
Table 2 kiln temperature deviation changes the assignment table
Table 3 rotary kiln fuel adjusting amount fuzzy quantity assignment table
4) fuzzy control rule is determined:
Mamdani (Ma Danni) control law sees Table 4
Table 4 rotary kiln fuel fuzzy control rule table
5) fuzzy reasoning
In the control law each conditional statement to should have fuzzy relation Rij=(Ti * Cij of Ai * Bj),, wherein Ai, Bj, Cij are respectively the fuzzy subset who is defined on E, Ec, the U.The fuzzy relation R=Rl1 v Rl2 v of the whole system that whole fuzzy control rules is determined ... Rij v ... Rnm.
Behind given input E*, EC*.(the Ti R of E* * EC*) asks for corresponding fuzzy control quantity according to fuzzy reasoning composition rule U*=.Rotary kiln fuel control law table according to the method is released sees Table 5:
Table 5 rotary kiln fuel winding-up control law table
6) ambiguity solution of output quantity
The controlled quentity controlled variable U* that is obtained by fuzzy reasoning is the fuzzy subset on the fuzzy language variable U domain, and the quantized value U by the controlled amount of defuzzification computing multiply by scale factor ku, obtains the exact value u of controlled quentity controlled variable, imposing on controlled device by D/A conversion output.