The flow control methods of AOD converter cross air blow gun barrel road system
Technical field
The present invention relates to the Flow-rate adjustment control of gas, more specifically, is the flow control methods of a kind of AOD converter cross air blow gun barrel road system.
Background technology
AOD (argon oxygen decarburization) converter side-blown air pressure gun has side-blown stirring, oxygen blast function.In application, side-blown gas divides multi-wad join to the furnace wall.Shielding gas comprises nitrogen and argon gas, can be switched by the trip valve on the house steward.Be illustrated in figure 1 as a kind of control principle synoptic diagram that comprises the AOD converter cross air blow gun barrel road system of seven pipelines.Each minute pipeline shielding gas respectively by pressure unit PT (such as orifice plate differential pressure transmitter etc.), temperature sensor TE (such as hot resistance etc.), flow regulating and controlling valve CV Comprehensive Control; nitrogen and argon gas be respectively by flowing into house steward 10 behind the trip valve SV, then enters each minute pipeline 11,12..., 17.The gas flow that each divides pipeline utilizes the temperature and pressure compensation mode to regulate.Utilize namely that the flow behind the set(ting)value flow and temperature and pressure compensation compares between each pipeline, the output aperture of adjust flux valve CV then is to regulate the gas flow of each minute pipeline output.
Usually, temperature and pressure compensation can utilize PID (ratio, integration, differential) control method to come the output aperture of adjust flux variable valve.The PID control method is control device ripe in the industry, and realizes by various PID controllers.Particularly, the PID controller is comprised of ratio unit P, integral unit I and differentiation element D.The PID controller mainly is applicable to substantially linear and kinetic characteristic time invariant system.The PID controller is comprised of ratio unit (P), integral unit (I) and differentiation element (D).Its input e (t) is u (t)=kp (e (t)+1/TI ∫ e (t) dt+TD*de (t)/dt) with the pass of output u (t), in the formula, the bound of integration is respectively 0 and t, so its transport function is: G (s)=U (s)/E (s)=kp (1+1/ (TI*s)+TD*s).Wherein kp is scale-up factor; TI is integration time constant; TD is derivative time constant.In flow control, can pass through PID controller input feedback amount, and carry out Flow-rate adjustment by the output aperture of adjust flux variable valve.
Particularly, referring to Fig. 2, carry out each piping flow adjusting synoptic diagram in the system of cross air blow gun barrel road for the existing PID of utilization control, only show the situation of a minute pipeline among the figure, the Flow-rate adjustment control of pipeline is all identical for other minute.
As shown in the figure, at first, the PID controller is according to the not compensating flowrate set(ting)value of input, and output valve aperture analog quantity A after flow regulating and controlling valve CV receives this analog quantity, sets the control valve aperture.
Then, when system is in steady operational status, utilize minute pipeline pressure P of pressure unit PT output in minute pressure reduction dP of pipeline aperture plate pressure difference transmitter (not shown) output (being the pressure difference value of check point before and after the orifice differential pressure transmitter aperture plate), minute pipeline and the actual temperature T of hot resistance output, calculate the flow under the standard state:
(formula 1)
In the formula, Q
1Be flow before not compensating, k is orifice plate flow design coefficient, and dP is the differential pressure that the orifice plate of orifice differential pressure transmitter PT collects, and ρ is the gas density under the design conditions.
Next, carry out flow rate calculation behind the temperature and pressure compensation:
(formula 2)
In the formula, T
0For design temperature (℃), P
0Be design pressure (MPa) that P is true pressure (MPa), T be actual temperature (℃), Q
1Be flow before not compensating, Q is the rear flow of compensation.
After calculating is finished, flow Q inputs to the PID controller as the feed back input amount after the compensation after temperature and pressure compensation calculates, the PID controller is by set(ting)value and feed back input amount Q, the valve opening amount of output behind temperature and pressure compensation, and then flow regulating and controlling valve regulated, thereby reach the purpose of each minute pipeline temperature and pressure compensation.
But, according to aforesaid method, in case stopping state appears in the gas of a certain minute pipeline, pressure P in this minute pipeline can significantly rise, if according to the flow rate calculation behind the temperature and pressure compensation, perhaps actual flow can reach the flow of setting, but the decline that the differential pressure dP that the orifice differential pressure detector in this moment minute pipeline detects can certain amplitude is reducing according to formula 1 detected actual flow velocity.That is to say that line clogging is serious, the gas circuit pressure P is larger, regulates control according to the flow PID behind the temperature and pressure compensation, can be more and more lower to the setting flow velocity requirement of pipeline, can aggravate so on the contrary the obstruction of pipeline.In case and AOD side-blown shielding gas stops up, then the pipeline that will blow side easily of the high-temperature molten steel in the AOD burns logically, cause smelting interruption, even the bleed-out accident.
Therefore, need a kind of flow control methods of new AOD converter cross air blow gun barrel road system, to solve the problems referred to above of existing flow control.
Summary of the invention
Purpose of the present invention, be to provide a kind of flow control methods of AOD converter cross air blow gun barrel road system of innovation, to solve the problems referred to above that exist in the flow control of existing AOD converter side-blown air pressure gun, thereby safety and precise ground is according to practical situation, and the gas flow of each pipeline carries out regulating and controlling in the offside wind blowing gun.
For achieving the above object, the invention provides the flow control methods of a kind of AOD converter cross air blow gun barrel road system, described AOD converter cross air blow gun barrel road system comprises a main pipe rail and a plurality of minutes pipelines that are connected with this main pipe rail, is respectively arranged with in the described minute pipeline for measuring a minute pipeline true pressure P
MinuteMinute pipeline pressure unit, be used for measuring a minute pipeline actual temperature T
MinuteTemperature sensor and flow regulating and controlling valve that be used for to regulate minute pipeline flow, the method may further comprise the steps:
Step 1 arranges the main pipe rail pressure unit at described main pipe rail, measures the main pipe rail true pressure P in the main pipe rail
Always
Step 2 was with a certain minute pipeline true pressure P
MinuteWith this minute pipeline setting pressure P
0Compare,
If a is P
Minute≤ 1.2P
0, then to carry out flow control and regulate, this flow control is regulated and is comprised: utilize main pipe rail true pressure P
Always, this minute pipeline actual temperature T
MinuteAnd this minute pipeline actual flow Q
0Carry out temperature and pressure compensation and calculate, calculate temperature and pressure compensation flow value of feedback Q
Minute, and utilize this temperature and pressure compensation flow value of feedback Q
MinuteAperture to the flow regulating and controlling valve in this minute pipeline is regulated;
If b is P
Minute>1.2P
0Then according to the predetermined pressure adjustable value, aperture to flow control valve is regulated, to utilize in the given time this predetermined pressure adjustable value, this pipeline is carried out high pressure blow logically, after described scheduled time finished, the flow control of carrying out among the above-mentioned condition a was regulated, wherein, described predetermined pressure adjustable value is not less than 1.4P
0, the described scheduled time is 1 to 5 minute.
Preferably, described this temperature and pressure compensation flow value of feedback Q that utilizes
MinuteAperture to the flow regulating and controlling valve in this minute pipeline is regulated, and utilizes pid control mode to carry out.
Preferably, described according to the predetermined pressure adjustable value, the aperture of flow control valve is regulated, utilize pid control mode to carry out.
Preferably, the described main pipe rail true pressure P that utilizes
Always, this minute pipeline actual temperature T
MinuteAnd this minute pipeline actual flow Q
0Carry out temperature and pressure compensation and calculate, adopt following formula to carry out:
T wherein
0Design temperature for this minute pipeline.
Preferably, further comprising the steps of:
Divided pipeline true pressure P when arbitrary minute in the pipeline
MinuteSatisfy 1.6P
Minute≤ P
Always, and described house steward's actual flow be lower than house steward set flow 80% the time, this AOD converter cross air blow gun barrel road system out of service.
The flow control methods of AOD converter cross air blow gun barrel of the present invention road system, adopt total pipe pressure to carry out temperature and pressure compensation for a minute pipeline gas flow, and utilize Flow-rate adjustment and pressure to regulate two kinds of control modes, be conducive to the unimpeded of gas piping, ensure the safe and reliable of the normal operation of AOD converter cross air blow gun barrel road system and smelting process.
Description of drawings
Fig. 1 is the control principle synoptic diagram of AOD converter cross air blow gun barrel road system;
Fig. 2 is the existing principle schematic of utilizing the temperature and pressure compensation method piping flow to be carried out PID control;
Fig. 3 is the schematic flow sheet of the flow control methods of AOD converter cross air blow gun barrel of the present invention road system;
Fig. 4 is the schematic flow sheet when adopting Flow-rate adjustment control in the flow control methods of AOD converter cross air blow gun barrel of the present invention road system;
Fig. 5 is the control principle synoptic diagram corresponding with flow process among Fig. 4;
Fig. 6 is the schematic flow sheet when adopting pressure to regulate control in the flow control methods of AOD converter cross air blow gun barrel of the present invention road system;
Fig. 7 is the control principle synoptic diagram corresponding with flow process among Fig. 6.
Embodiment
Below with reference to the accompanying drawings and embodiment, step and the principle of the flow control methods of AOD converter cross air blow gun barrel of the present invention road system are elaborated.For being illustrated more clearly in essence of the present invention, method and apparatus conventional among the present invention is only made brief description, and in the accompanying drawings, identical parts utilize identical label to represent.
At first with reference to Fig. 1, Fig. 5 and Fig. 7, the flow control methods of AOD converter cross air blow gun barrel of the present invention road system, be used to the gas flow of each pipeline in the system of AOD converter cross air blow gun barrel road to carry out regulating and controlling, with above-mentioned similar to the explanation among Fig. 1, AOD converter cross air blow gun barrel road system comprises a main pipe rail 10 and a plurality of minutes pipelines being connected with this main pipe rail (in the embodiment of the present invention be in charge of way and Fig. 1 is identical, it is seven, comprise minute pipeline 11, divide pipeline 12... to divide pipeline 17), be respectively arranged with in the described minute pipeline for measuring a minute pipeline true pressure P
MinuteMinute pipeline pressure unit PT, be used for measuring a minute pipeline actual temperature T
MinuteTemperature sensor TE and the flow regulating and controlling valve CV that be used for to regulate minute pipeline flow.As previously mentioned, nitrogen and argon gas be respectively by flowing into house steward 10 behind the trip valve SV, then enters each minute pipeline 11,12..., 17.Divide pipeline pressure unit PT, temperature sensor TE, flow control valve CV and trip valve SV all to select conventional components suitable in this field.In addition, arrange identically with original, also be provided with orifice differential pressure transmitter (not shown) in each minute pipeline, be used for utilizing the pressure reduction that detects to divide the actual flow of pipeline to calculate to its place.
As shown in Figure 3, be total schematic flow sheet of the flow control methods of AOD converter cross air blow gun barrel of the present invention road system.Below in conjunction with Fig. 3 and other necessary accompanying drawings, each step is elaborated.
As shown in Figure 3, and with reference to Fig. 5,7, in step S100, at main pipe rail 10 main pipe rail pressure unit PT0 is set, measures the main pipe rail true pressure P in the main pipe rail 10
AlwaysMain pipe rail pressure unit PT0 on the main pipe rail 10 can select conventional pressure unit, detects the as a result P of measurement with the true pressure to main pipe rail
AlwaysBeing used for follow-up temperature and pressure compensation calculates.
In step S200, with a certain minute pipeline true pressure P
MinuteWith a minute pipeline setting pressure P
0Compare, to determine adopting Flow-rate adjustment control or pressure to regulate control mode.Divide pipeline setting pressure P
0Pressure for lower minute pipeline gas of normal unimpeded state.
More specifically, as shown in Figure 4, the schematic flow sheet during for the control of employing Flow-rate adjustment, as shown in the figure, in step S210, if P
Minute≤ 1.2P
0, then carry out flow control and regulate, particularly, this flow control is regulated and is comprised: in step S212, utilize main pipe rail true pressure P
Always, this minute pipeline actual temperature T
MinuteAnd this minute pipeline actual flow (namely do not carry out temperature and pressure compensation before flow) Q
0Carry out temperature and pressure compensation and calculate, calculate temperature and pressure compensation flow value of feedback Q
Minute, and, in step S214, utilize this temperature and pressure compensation flow value of feedback Q
MinuteAperture to the flow regulating and controlling valve in this minute pipeline is regulated.
Further combined with Fig. 5.For simplicity, only shown the control principle that minute pipeline 11 is carried out flow control among Fig. 5, understood easily, for the flow control principle of other minute pipeline, identical with minute pipeline 11.As shown in the figure, after determining to select flow control to regulate, utilize the main pipe rail true pressure P that records
Always, this minute pipeline actual temperature T
MinuteAnd this minute pipeline actual flow Q
0, utilize following formula to carry out temperature and pressure compensation and calculate, draw the flow value of feedback Q behind the temperature and pressure compensation
Minute:
(formula 3)
In the following formula, T
0Be the design temperature of this minute pipeline, namely under the normal unimpeded state this minute pipeline temperature.Actual flow Q
0, can utilize the orifice differential pressure transmitter that is arranged on minute pipeline to calculate according to aforementioned formula 1.
Compare with existing temperature and pressure compensation method, in the temperature and pressure compensation scheme that the present invention adopts, adopt main pipe rail true pressure P
AlwaysFor a minute pipeline gas flow carries out temperature and pressure compensation, and temperature parameter still adopts and is in charge of temperature.The calculating of temperature and pressure compensation and calculation of correlation (actual flow Q for example
0), can finish by ordinary method, for example carry out above temperature and pressure compensation by computer, dedicated digital signal processor or PLC (PLD) chip and calculate.
Thus, in case obstruction or Partial Blocking situation, the pressure P of this gas circuit appear in a certain minute pipeline (for example dividing pipeline 11) gas
MinuteSignificantly rise, but house steward's pressure P
AlwaysVariation is little, and namely this moment, the orifice plate differential pressure of minute pipeline aperture plate pressure difference transmitter changed not quite by the requirement of set(ting)value, and the flow velocity of the reality that therefore calculates also changes not quite, thereby is conducive to the unobstructed of pipeline, prevents that the phenomenon of line clogging aggravation from producing.
When utilizing temperature difference compensation step of the present invention to calculate temperature and pressure compensation flow value of feedback Q
MinuteAfter, can utilize this temperature and pressure compensation flow value of feedback Q
MinuteAperture to the flow regulating and controlling valve in this minute pipeline is regulated.In embodiments of the present invention, utilize this temperature and pressure compensation flow value of feedback Q
MinuteAperture to the flow regulating and controlling valve in this minute pipeline is regulated, and can utilize pid control mode to carry out.This pid control mode is identical with the pid control mode of aforementioned available technology adopting, namely utilizes the PID controller, with flow setting value Q
0With flow value of feedback Q behind the temperature and pressure compensation that calculates
MinuteAs input, after the PID controller calculates, obtain the work output A of valve opening, and this work output is delivered to flow regulating and controlling valve CV in this minute pipeline, the valve opening of adjust flux adjusting control valve CV, thus reach according to flow value of feedback Q
MinuteThe flow purpose of regulating to this minute pipeline.Certainly, utilizing temperature and pressure compensation step of the present invention to calculate flow value of feedback Q
MinuteAfter, also can adopt other known control program, the valve opening of flow regulating and controlling valve CV is regulated.
On the other hand, referring to Fig. 6, in step S220, if P
Minute>1.2P
0, then according to the predetermined pressure adjustable value, the aperture of flow control valve is regulated, to utilize in the given time this predetermined pressure adjustable value, this pipeline is carried out high pressure blow logical; In step S222, after the scheduled time finishes, proceed flow control according to step S212, S214 and regulate.
Particularly, as fruit P
Minute>1.2P
0The time, illustrating has latch up phenomenon to produce in this minute pipeline, then can utilize higher predetermined pressure adjustable value, the aperture of flow regulating and controlling valve CV is adjusted accordingly, thus to this minute pipeline carry out high pressure and blow logical.Referring to Fig. 7, described according to the predetermined pressure adjustable value, the aperture of flow control valve is regulated, also can utilize pid control mode to carry out.Particularly, after judgement has latch up phenomenon to produce, system switches to the pattern of utilizing pressure set points that flow regulating and controlling valve is regulated, the force value of PID controller (referring to PID control 1 among Fig. 7) reception minute pipeline pressure unit PT output and predetermined pressure adjustable value are as input, after PID calculates, export the regulation amount to flow regulating and controlling valve CV, thereby reach the purpose of utilizing the predetermined pressure adjustable value that flow regulating and controlling valve CV is regulated.Usually, for reaching pipeline is blown logical purpose, the predetermined pressure adjustable value is usually higher, and in a preferred embodiment of the present invention, the predetermined pressure adjustable value is not less than 1.4P
0
Utilize higher predetermined pressure that a minute pipeline that stops up is carried out high pressure and blow in the logical scheduled time, can again adopt the Flow-rate adjustment control mode (referring to PID control 2 among Fig. 7) of above-mentioned S212, S214.This be because, adopt high pressure to blow logical mode, mainly be to blow logical to minute pipeline that obstruction is arranged, blow after logical operation finishes until this, no matter whether a minute pipeline latch up phenomenon is eliminated, all should get back to the Flow-rate adjustment master mode, carry out the adjusting of flow control valve CV aperture in each minute pipeline with minute pipeline flow, temperature conditions according to reality.The scheduled time of blowing logical operation can not be too short, blows logical effect really to reach, and make a minute pipeline flow reach stable, still can not be oversize, carry out Flow-rate adjustment to avoid realizing each minute pipeline according to truth.In an embodiment of the invention, this scheduled time is 1-5 minute, is preferably 3 minutes.
Referring to Fig. 3, the present invention also can preferably include step S300, namely after step S100, step S200, judges in the system of AOD converter cross air blow gun barrel road whether have fault.Particularly, minute pipeline true pressure P in arbitrary minute pipeline
MinuteSatisfy 1.6P
Minute≤ P
Always, and described house steward's actual flow be lower than house steward set flow 80% the time, this AOD converter cross air blow gun barrel road system out of service.Hypotony (1.6P in minute pipeline
Minute≤ P
Always), and house steward's actual flow obviously descend (be lower than house steward set flow 80%) time, illustrate that minute pipeline produces comparatively serious latch up phenomenon, should utilize and close trip valve SV this moment, stop nitrogen and argon gas to the supply of piping system, with AOD converter cross air blow gun barrel out of service road system, thereby end whole smelting process, ensure and smelt safety.
To sum up, the flow control methods of AOD converter cross air blow gun barrel of the present invention road system, adopt total pipe pressure to carry out temperature and pressure compensation for a minute pipeline gas flow, and utilize Flow-rate adjustment and pressure to regulate two kinds of control modes, be conducive to the unimpeded of gas piping, ensure the safe and reliable of the normal operation of AOD converter cross air blow gun barrel road system and smelting process.