CN103207632B - Control system and control method for coal gas mixed pressure regulating - Google Patents

Abstract

The invention discloses a control system and a control method for coal gas mixed pressure regulating. The control system comprises a feedforward calculating unit, a pressure controller output feedforward calculating unit, a feedforward coke oven gas calculating unit and a feedforward blast furnace gas calculating unit. The feedforward calculating unit is used for calculating a feedforward compensation value according to the mixed coal gas flow of each branch tube and the mixed coal gas flow of a main tube in a heating furnace and calculating the feedforward amount of coke oven gas according to the feedforward compensation value. The pressure controller output feedforward calculating unit is used for calculating the output value of a pressure controller with feedforward compensation according to the feedforward amount of the coke oven gas. The feedforward coke oven gas calculating unit is used for performing feedforward compensation on a coke oven gas decoupling calculating unit. The feedforward blast furnace gas calculating unit is used for performing feedforward compensation on measured flow of the coke oven gas. By means of the control system and the control method for coal gas mixed pressure regulating, tracking on coal gas flow and pressure after one-time mixing of the coke over gas flow and the blast furnace gas flow can be well achieved, so that thermal requirement response of a heating furnace can be met.

Description

The control system regulated for coal gas blend pressure and method

Technical field

The present invention relates to the pressurized control to mixed gas, more specifically, is a kind of control system for the adjustment of coal gas blend pressure and method.

Background technology

In modern steel enterprise, most of firing equipment, as heating furnace etc., is all provide heat energy by mixed gas burning, as shown in Figure 1, mainly comprises coke-oven gas COG, blast furnace gas BFG and coal gas of converter LDG.Wherein, three flow control valves SV1, SV2 and SV3 are used for regulating the flow of coke-oven gas, blast furnace gas and coal gas of converter respectively, temperature detector T1, T2 and T3 is respectively used to detect the temperature in different pipeline, and pressure detector P1, P2, P3, P4, P5 and Ps are for detecting the pressure in different pipeline.Flow detector FI1, FI2 and FI3 are used for detecting the flow in each pipeline.

Continue composition graphs 1, for above-mentioned three kinds of coal gas, blast furnace gas BFG and coke-oven gas COG, according to calorific value demand, is carried out mixed once by Gas Pressurization Station by a certain percentage, after pressuring machine pressurization, carry out secondary with coal gas of converter again to mix, then flow to heating furnace according to certain pressure requirements to use, the secondary for coal gas of converter mixes, and its combined amount only needs to mix according to coke-oven gas and blast furnace gas sum-rate, without calorific value control overflow, therefore control comparatively simple.In each gas flow controls, generally have employed the flow control of large tubule to improve the regulating power under different flow demand.Mixed once process before pressuring machine pressurization meets the key that mixed gas calorific value controls, and needs again pressure before stable pressuring machine in controlling simultaneously.But because calorific value and pressure have stronger coupling, therefore it controls to be the problem that in mixed gas pressurization Automated condtrol one is comparatively complicated.Particularly when heating furnace is because of under fault or shutdown situation; when coal gas demand is subject to disturbing compared with large disturbances; mixed gas mixed once regulates often to be existed certain delayed, and system easily produces over-control, and needs again to enter steady state (SS) for a long time.

To sum up, mixed gas pressurization is multi input double-outputting system, directly or indirectly impact is there is in controlled quentity controlled variable on output pressure, calorific value, namely there is strong coupling effect between them, this has had a strong impact on the stable of mixed gas pressure and calorific value, therefore, for reducing the fluctuation of mixed gas pressure and calorific value, decoupling zero link must be introduced.

As shown in Figure 2, be a kind of typical mixed once gas pressure and calorific value uneoupled control loop, the major loop that it is controlled by mixed once gas pressure controller PICs and coke gas flow controls, blast furnace gas flow controls two subloops and controls to form.Mixed once gas pressure controller and coke oven and blast furnace flow controller all adopt PID to control.PID controls mainly to be applicable to substantially linear and dynamic perfromance time invariant system, is control device conventional in industry.Composition graphs 1,2, wherein, in major loop, pressure controller PICs according to the pressure measuring value PVs recorded after mixed once and setting value SPs, output pressure controller output valve OP, control in subloop at coke gas flow, the blast furnace gas flow that FI2 records and the coal gas of converter flow that FI3 records are after the decoupling computation in this loop computing unit F (X1), export to the selection unit SL1 in this loop, in this selection unit, the output valve of F (X1) in selection unit through the adjustment of amplitude limit proportional control factor K1, export high choosing value and low choosing value, the output valve OP of two values and pressure controller PICs compares, get the desired value SP1 of median as coke gas flow controller FIC1, flow controller FIC1 and then according to this desired value SP1 and the coke gas flow measured value PV1 that records, the variable valve SV1 of coke-oven gas is regulated, similarly, control in subloop at blast furnace gas flow, the coke gas flow that FI1 records is selected through selection unit SL2, in this selection unit, regulate according to amplitude limit proportional control factor K2, export high choosing value and low choosing value, after it compares with pressure controller output valve OP, get the decoupling computation of median through computing unit F (X2), draw the desired value SP2 of blast furnace gas flow controller FIC2, flow controller FIC2, according to this desired value SP2 and the blast-furnace gas pressure measured value PV2 that records, regulates the variable valve SV2 of coke-oven gas.In above-mentioned three loops, pressure controller PICs, coke gas flow controller FIC1 and blast furnace gas flow controller FIC2 can utilize PID control method conventional in industry to control.The value of amplitude limit proportional control factor K1, K2 controls needs according to actual amplitude limit and sets, and its scope is generally 0.4-1.4, and in addition, the computing unit F (X1) of two subloops and the computation model of F (X2) are respectively:

$F\left(X1\right)=\frac{F_{\mathrm{BFG}}\×R_{\mathrm{BFG}}\×(Q_{\mathrm{MG}}-Q_{\mathrm{BFG}})+F_{\mathrm{LDG}}\×R_{\mathrm{LDG}}\×(Q_{\mathrm{MG}}-Q_{\mathrm{LDG}})}{(Q_{\mathrm{COG}}-Q_{\mathrm{MG}})\×R_{\mathrm{COG}}}---\left(1\right)$

$F\left(X2\right)=\frac{F_{\mathrm{COG}}\×R_{\mathrm{COG}}\×(Q_{\mathrm{MG}}-Q_{\mathrm{COG}})+F_{\mathrm{LDG}}\×R_{\mathrm{LDG}}\×(Q_{\mathrm{MG}}-Q_{\mathrm{LDG}})}{(Q_{\mathrm{BFG}}-Q_{\mathrm{MG}})\×R_{\mathrm{BFG}}}---\left(2\right)$

Wherein, F _bFG: blast furnace gas total flow measured value (%); R _bFG: the blast furnace gas total flow range upper limit (unit is that normal cubic metre is per hour); F _lDG: coal gas of converter total flow measured value (%); R _lDG: the coal gas of converter total flow range upper limit (unit is that normal cubic metre is per hour); F _cOG: coke-oven gas total flow measured value (%); R _cOG: the coke-oven gas total flow range upper limit (unit is that normal cubic metre is per hour); Q _mG: mixed gas target calorific value; Q _cOG: coke-oven gas calorific value; Q _lDG: coal gas of converter calorific value; Q _bFG: blast furnace gas calorific value.

As shown in Figure 3, above-mentioned decoupling zero loop is utilized to carry out mixed gas pressure adjustment, can be divided into following steps: in step sl, mixed once pressure controller, according to mixed once target pressure value and mixed once measured pressure value, calculates pressure controller output valve through PID; In step s 2, according to blast furnace gas and coal gas of converter flow value through decoupling computation, and carry out amplitude limit adjustment, obtain the high and low limit value of coke oven decoupling zero, after this high and low limit value and pressure controller output valve compare, get median and be input to coke gas flow controller, and according to the spacing adjustment of coke gas flow value with compare with pressure controller output valve, get median after decoupling computation, be input to blast furnace gas flow controller; Next, in step s3, coke gas flow controller is according to the coke-oven gas pressure target value and the coke-oven gas pressure measuring value that calculate gained, coke-oven gas variable valve is regulated, and blast furnace gas flow controller, according to blast-furnace gas pressure desired value and blast-furnace gas pressure measured value, regulates blast furnace gas variable valve.

Above-mentioned control program can carry out cross decoupling operation according to the flow of each producer gas and pressure, but it has obvious Delay Process, each controller can not get suitable feedback signal and keeps increasing within the delayed time, causes system responses overshoot, even makes system down.This is because in delayed time phase, control action is immesurable for multivariable process, and produce overshoot, what extend system enters the stable time.For above-mentioned bi-cross limitation control, the restriction of amplitude limit scale-up factor slow down the regulating action of PID controller to flow and pressure, which in turns increases the delayed of adjustment.

As shown in Figure 4; if when the operation of well afoot is because of fault cancel closedown; cause mixed once gas pressure PVs and secondary blend pressure PVt to occur fluctuation, now coke gas flow measured value F1 and blast furnace gas flow measurements F2 not follow-up at once, but there is a retardation time.And when the pressure P Vs after mixed once gets back to control objectives, the output of the flow controller in above-mentioned two subloops still continues to increase, thus make system produce overshoot, thereafter need just can return to steady state (SS) for a long time, and calorific value Q (referring to the calorific value being finally sent to the coal gas of heating furnace after mixing, i.e. the mixed calorific value of the secondary) wave process before and after this plays pendulum always.

Therefore, need, on the basis of above-mentioned control program, to improve, to eliminate the large defect of response lag and hot-restriking die in this existing program, thus improve the pressure of mixed gas is regulated.

Summary of the invention

Object of the present invention, is to solve the problems referred to above existing in existing mixed gas pressure regulating and controlling, thus provides a kind of control system for the adjustment of coal gas blend pressure and method of improvement.

The control system regulated for coal gas blend pressure of the present invention, comprise mixed once major loop, coke gas flow controls subloop and blast furnace gas flow controls subloop, wherein, described mixed once major loop comprises mixed once gas pressure controller, described coke gas flow controls subloop and comprises coke-oven gas decoupling computation unit, coke-oven gas selection unit and coke gas flow controller, described blast furnace gas flow controls subloop and comprises blast furnace gas selection unit, blast furnace gas decoupling computation unit and blast furnace gas flow controller, this control system also comprises:

Feedforward computing unit, for according to each arm flow of the mixed gas in heating furnace and house steward's flow, calculates feedforward compensation value, and calculates coke-oven gas feedforward amount according to this feedforward compensation value;

Pressure controller exports feedforward computing unit, for according to described coke-oven gas feedforward amount, calculates the pressure controller output valve of band feedforward compensation;

Feedforward coke-oven gas computing unit, for according to described coke-oven gas feedforward amount, carries out band feedforward compensation to described coke-oven gas decoupling computation unit; And

Feedforward blast furnace gas computing unit, for according to described coke-oven gas feedforward amount, carries out band feedforward compensation to the measuring flow of coke-oven gas.

Control method for the adjustment of coal gas blend pressure of the present invention comprises the steps:

A, mixed once pressure controller, according to mixed once target pressure value and mixed once measured pressure value, calculates pressure controller output valve;

B, according to each arm flow of the mixed gas in heating furnace and house steward's flow, calculates feedforward compensation value, and calculates coke-oven gas feedforward amount according to this feedforward compensation value;

C, according to described coke-oven gas feedforward amount and described pressure controller output valve, calculate the pressure controller output valve of band feedforward compensation, and the coke-oven gas selection unit be delivered in coke gas flow control subloop and blast furnace gas flow control the blast furnace gas selection unit in subloop;

D, according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop, and the coke-oven gas selection unit be delivered in this coke gas flow control subloop, and: according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the measuring flow of coke-oven gas, and is delivered to the blast furnace gas selection unit in this blast furnace gas flow control subloop;

E, the coke oven controling parameters that coke gas flow controller is determined according to this coke-oven gas selection unit, coke-oven gas variable valve is regulated, and: the selective value that blast furnace gas selection unit is determined calculates through blast furnace gas decoupling computation unit, draw blast furnace controling parameters, blast furnace gas flow controller, according to this blast furnace controling parameters, regulates blast furnace gas variable valve.

Preferably, in described step b, according to each arm flow of the mixed gas in heating furnace and house steward's flow, the formula calculating feedforward compensation value is:

$\mathrm{\ΔX}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{DMDi}}-F_{\mathrm{MG}}+(F_{\mathrm{MG}}-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{PVi}}){\mathrm{\×K}}_{\mathrm{MG}\_\mathrm{DEV}}+F_{\mathrm{\ΔDEV}};$

In formula, Δ X: feedforward compensation value; heating furnace meets the coal gas total amount required for heat supply; F _mG: the current house steward's flow of mixed gas; mixed gas each arm flow summation in heating furnace; K _{mG_DEV}: mixed gas house steward and arm drift correction coefficient; F _{Δ DEV}: heating furnace and gas station droop modified value; And:

The formula calculating coke-oven gas feedforward amount according to this feedforward compensation value is:

${\mathrm{\ΔX}}_{\mathrm{COG}}=\mathrm{\ΔX}\×(1-R_{\mathrm{LDG}})\×K_{\mathrm{COG}}\×\frac{F_{\mathrm{COG}}}{R_{\mathrm{COG}}\×(F_{\mathrm{COG}}+F_{\mathrm{BFG}})}\text{;}$

In formula, Δ X _cOG: coke-oven gas feedforward amount; R _lDG: the coal gas of converter total flow range upper limit; K _cOG: correction factor; F _cOG: coke-oven gas total flow measured value; R _cOG: the coke-oven gas total flow range upper limit; F _bFG: blast furnace gas total flow measured value.

Preferably, in described step c, according to described coke-oven gas feedforward amount and described pressure controller output valve, calculate the pressure controller output valve of band feedforward compensation, computing formula is:

${{\mathrm{OP}}_{\mathrm{COG}}}^{\′}=(\mathrm{OP}+\frac{{\mathrm{\ΔX}}_{\mathrm{COG}}}{R_{\mathrm{COG}}})\×R_{\mathrm{COG}};$

In formula, OP _cOG': the pressure controller output valve of band feedforward compensation; OP: pressure controller output valve.

Preferably, in described steps d, band feedforward compensation is carried out to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop, utilizes following formula to carry out:

F(X1)'＝ΔX _COG×K ₃+F(X1)；

Wherein, F (X1) ': the output valve after band feedforward compensation; K ₃: compensating approach coefficient; F (X1): coke-oven gas decoupling computation unit output valve.

Preferably, in described steps d, band feedforward compensation is carried out to the measuring flow of coke-oven gas, utilizes following formula to carry out:

F(X3)＝ΔX _COG×K ₃+F _COG；

In formula, F (X3) be to the measuring flow band feedforward compensation of coke-oven gas after output valve.

Control system for the adjustment of coal gas blend pressure of the present invention and method, the tracking to gas flow after mixed once and pressure of coke gas flow and blast furnace gas flow can be realized well, thus meet the heat demand response of heating furnace, avoid the shortcoming that can not correctly respond and regulate brought because of hysteresis quality in existing regulating measure.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of mixed gas pressurizing point;

Fig. 2 is mixed once gas pressure and calorific value decoupling and controlling system schematic diagram;

Fig. 3 is the process flow diagram utilizing the control system in Fig. 2 to carry out mixed gas pressure adjustment;

Fig. 4 is the curve synoptic diagram of regulation scheme in Fig. 2,3;

Fig. 5 is the composition schematic diagram of the control system for the adjustment of coal gas blend pressure of the present invention;

Fig. 6 is the process flow diagram of the control method for the adjustment of coal gas blend pressure of the present invention;

Fig. 7 is the curve synoptic diagram utilizing control method of the present invention to regulate coal gas blend pressure.

Embodiment

Below with reference to the accompanying drawings and embodiment, the composition of the control system that regulates for coal gas blend pressure of the present invention and method, step and principle of work are described in detail.

As shown in Figure 5, it is the composition schematic diagram of the control system for the adjustment of coal gas blend pressure of the present invention, this control system be in fig. 2 shown in uneoupled control loop basis on improve, for corresponding with Fig. 2, identical part utilizes identical label to mark.Particularly, similar with the uneoupled control loop in Fig. 2, control system of the present invention comprises mixed once major loop, coke gas flow controls subloop and blast furnace gas flow controls subloop, wherein, mixed once major loop comprises mixed once gas pressure controller PICs, coke gas flow controls subloop and comprises coke-oven gas decoupling computation unit F (X1), coke-oven gas selection unit SL1 and coke gas flow controller FIC1, coke-oven gas decoupling computation unit F (X1), coke-oven gas selection unit SL1 is identical with Fig. 2 with the effect of coke gas flow controller FIC1, blast furnace gas flow control loop comprises blast furnace gas selection unit SL2, blast furnace gas decoupling computation unit F (X2) and blast furnace gas flow controller FIC2, and blast furnace gas selection unit SL2, blast furnace gas decoupling computation unit F (X2) are identical with Fig. 2 with the effect of blast furnace gas flow controller FIC2.Further combined with Fig. 2,5, on basis in fig. 2, control system of the present invention also comprises: feedforward computing unit C1, pressure controller export feedforward computing unit C2, feedforward coke-oven gas computing unit C3 and feedforward blast furnace gas computing unit C4.

Particularly, feedforward computing unit C1 is for according to each arm of the mixed gas in heating furnace, (each arm of mixed gas refers to that mixed coal gas is sent to the arm of each heating furnace, every stove is received on gas main by arm) flow and house steward (refer to the mixed gas main of secondary, this house steward leads to furnace area) flow, calculate feedforward compensation value Δ X, and calculate coke-oven gas feedforward amount Δ X according to this feedforward compensation value Δ X _cOG; Pressure controller exports feedforward computing unit C2 and is used for according to coke-oven gas feedforward amount Δ X _cOG, calculate the pressure controller output valve OP of band feedforward compensation _cOG'; Feedforward coke-oven gas computing unit C3 is used for according to coke-oven gas feedforward amount Δ X _cOG, band feedforward compensation is carried out to described coke-oven gas decoupling computation unit F (X1); Feedforward blast furnace gas computing unit is used for according to coke-oven gas feedforward amount Δ X _cOG, band feedforward compensation is carried out to the measuring flow of coke-oven gas.For being illustrated more clearly in the present invention, feedforward computing unit C2, feedforward coke-oven gas computing unit C3 and feedforward blast furnace gas computing unit C4 are exported for feedforward computing unit C1, pressure controller, by combining the control method regulated for coal gas blend pressure of the present invention based on this control system, be described in detail.

As shown in Figure 6, be based on above-mentioned control system of the present invention, to the process flow diagram of the control method that coal gas blend pressure regulates, as shown in the figure, the method comprising the steps of S100-S500, below in conjunction with Fig. 5,6, is described in detail to each step.

step S100

In this step, mixed once pressure controller, according to mixed once target pressure value and mixed once measured pressure value, calculates pressure controller output valve.

Identical with the scheme that prior art is taked, mixed once pressure controller PICs for input parameter, carries out PID controlling calculation with mixed once target pressure value SPs and mixed once measured pressure value PVs, draws pressure controller output valve OP.

step S200

In this step, according to each arm flow of the mixed gas in heating furnace and house steward's flow, calculate feedforward compensation value, and calculate coke-oven gas feedforward amount according to this feedforward compensation value.

Composition graphs 5, the calculating of feedforward compensation value and coke-oven gas feedforward amount, can utilize feedforward computing unit C1 to come.

Particularly, in this feedforward computing unit, for the calculating of feedforward compensation value, carry out according to following formula:

$\mathrm{\ΔX}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{DMDi}}-F_{\mathrm{MG}}+(F_{\mathrm{MG}}-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{PVi}}){\mathrm{\×K}}_{\mathrm{MG}\_\mathrm{DEV}}+F_{\mathrm{\ΔDEV}};---\left(3\right)$

In formula (3), Δ X: feedforward compensation value; heating furnace meets the coal gas total amount required for heat supply; F _mG: the current house steward's flow of mixed gas; mixed gas each arm flow summation in heating furnace; K _{mG_DEV}: mixed gas house steward and arm drift correction coefficient; F _{Δ DEV}: heating furnace and gas station droop modified value.In the above-mentioned amount of referring to parameter, for the known quantity obtained from the control system of heating furnace; K _{mG_DEV}the measurement deviation acting as the pick-up unit revising house steward and each arm, to reduce the error in calculating, its scope is between ± 1.

On this basis, according to this feedforward compensation value _Δthe formula that X calculates coke-oven gas feedforward amount is:

${\mathrm{\ΔX}}_{\mathrm{COG}}=\mathrm{\ΔX}\×(1-R_{\mathrm{LDG}})\×K_{\mathrm{COG}}\×\frac{F_{\mathrm{COG}}}{R_{\mathrm{COG}}\×(F_{\mathrm{COG}}+F_{\mathrm{BFG}})}\text{;---}\left(4\right)$

In formula (4), Δ X _cOG: coke-oven gas feedforward amount; And with in formula (1), (2), respectively the amount of referring to is identical, R _lDG: the coal gas of converter total flow range upper limit; K _cOG: correction factor, it is the result of calculation according to this formula of practical condition correction, and span is 0-1; F _cOG: coke-oven gas total flow measured value; R _cOG: the coke-oven gas total flow range upper limit; F _bFG: blast furnace gas total flow measured value.

step S300

In this step, according to coke-oven gas feedforward amount and described pressure controller output valve, calculate the pressure controller output valve of band feedforward compensation, and the coke-oven gas selection unit be delivered in coke gas flow control subloop and blast furnace gas flow control the blast furnace gas selection unit in subloop.

Particularly, when feedforward computing unit C1 calculates coke-oven gas feedforward amount Δ X _cOGafter, this result is inputed to pressure controller and export feedforward computing unit (i.e. OP feedforward computing unit) C2, OP feedforward computing unit C2 compensates calculating to pressure controller output valve OP, draw the output valve after feedforward compensation, OP feedforward computing unit C2 to the formula that OP compensates calculating is:

${{\mathrm{OP}}_{\mathrm{COG}}}^{\′}=(\mathrm{OP}+\frac{{\mathrm{\ΔX}}_{\mathrm{COG}}}{R_{\mathrm{COG}}})\×R_{\mathrm{COG}};---\left(5\right)$

In formula (5), OP _cOG': the pressure controller output valve of band feedforward compensation; OP: pressure controller output valve, other amount of referring to is various identical with above.

OP after utilizing OP feedforward computing unit C2 to calculate compensation _cOG' after, this offset is delivered to respectively coke-oven gas selection unit SL1 and blast furnace gas selection unit SL2.

step S400

In this step, according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop, and the coke-oven gas selection unit be delivered in this coke gas flow control subloop, and: according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the measuring flow of coke-oven gas, and is delivered to the blast furnace gas selection unit in this blast furnace gas flow control subloop.

This step comprises the step utilizing feedforward coke-oven gas computing unit C3 to carry out being with feedforward compensation, and comprises the step utilizing feedforward blast furnace gas computing unit C4 to carry out being with feedforward compensation.Particularly, feedforward coke-oven gas computing unit C3 carries out band feedforward compensation to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop, utilizes following formula to carry out:

F(X1)'＝ΔX _COG×K ₃+F(X1)； (6)

Wherein, F (X1) ': the output valve after band feedforward compensation; K ₃: compensating approach coefficient (it act as the result of calculation according to this formula of actual conditions correction, and span is 0-1); F (X1): coke-oven gas decoupling computation unit output valve.The calculating of F (X1) is see above-mentioned formula (1).

Composition graphs 5, after utilizing feedforward coke-oven gas computing unit C3 to calculate the output valve F (X1) ' with feedforward compensation, this output valve is transported to coke-oven gas selection unit SL1.

On the other hand, band feedforward compensation is carried out to the measuring flow of coke-oven gas, utilizes following formula to carry out:

F(X3)＝ΔX _COG×K ₃+F _COG； (6)

In formula, F (X3) be to the measuring flow band feedforward compensation of coke-oven gas after output valve.Other amount of referring to is various identical with above-mentioned.

Composition graphs 5, after utilizing feedforward blast furnace gas computing unit C4 to calculate the output valve F (X3) with feedforward compensation, this output valve is transported to blast furnace gas selection unit SL2.

step S500

In this step, the coke oven controling parameters that coke gas flow controller is determined according to this coke-oven gas selection unit, coke-oven gas variable valve is regulated, and: the selective value that blast furnace gas selection unit is determined calculates through blast furnace gas decoupling computation unit, draw blast furnace controling parameters, blast furnace gas flow controller, according to this blast furnace controling parameters, regulates blast furnace gas variable valve.

This step S500 similarly to the prior art.Particularly, control in subloop at coke gas flow, after selection unit SL1 receives the F (X1) ' that step S400 calculates, amplitude limit proportional control factor K1 is utilized to get high choosing and low choosing value, and then the pressure controller output valve OP of band feedforward compensation according to input _cOG', after getting median to three values, be input to coke-oven gas controller FIC as coke oven controling parameters, coke-oven gas controller FIC utilizes conventional PID controlling calculation method, exports controlled quentity controlled variable and regulates coke-oven gas variable valve SV1.Routinely, in PID controlling calculation, the output valve of pressure controller, the output valve after feedforward compensation and coke oven controling parameters are percentage, it calculates through PID the controlled quentity controlled variable exported also is percentage, this output controlled quentity controlled variable and valve opening proportional, thus realize adjustment to coke-oven gas variable valve SV1.

On the other hand, control in subloop at blast furnace gas flow, after selection unit SL2 receives the F (X3) drawn in step S400, amplitude limit proportional control factor K2 is utilized to get high choosing and low choosing value, and then the pressure controller output valve OP of band feedforward compensation according to input _cOG', after median is got to three values, F (X2) is utilized to carry out decoupling computation, draw blast furnace controling parameters, be similar to coke gas flow controller, blast furnace gas flow controller utilizes conventional PID controlling calculation method according to this blast furnace controling parameters, exports controlled quentity controlled variable, regulates blast furnace gas variable valve.

The increase that the present invention is calculated by each feedforward gauge, can in time for compensate to be input to each input quantity in coke gas flow controller and blast furnace gas flow controller, thus eliminate existing regulating system (regulable control loop as shown in Figure 2) and bring hysteresis quality.As shown in Figure 7, it is the curve synoptic diagram utilizing control method of the present invention to regulate coal gas blend pressure, as seen from the figure, when mixed once gas pressure Ps and secondary mixed gas pressure PVt changes, utilize control system of the present invention and control method, coke gas flow F1 and blast furnace gas flow F2 can be made to follow the tracks of adjustment fast, and the fluctuation of calorific value Q also remain in range of control.

In sum, control system for the adjustment of coal gas blend pressure of the present invention and method, the tracking to gas flow after mixed once and pressure of coke gas flow and blast furnace gas flow can be realized well, thus meet the heat demand response of heating furnace, avoid the shortcoming that can not correctly respond and regulate brought because of hysteresis quality in existing regulating measure.

Claims (6)

1. the control system regulated for coal gas blend pressure, comprise mixed once major loop, coke gas flow controls subloop and blast furnace gas flow controls subloop, wherein, described mixed once major loop comprises mixed once gas pressure controller, described coke gas flow controls subloop and comprises coke-oven gas decoupling computation unit, coke-oven gas selection unit and coke gas flow controller, described blast furnace gas flow controls subloop and comprises blast furnace gas selection unit, blast furnace gas decoupling computation unit and blast furnace gas flow controller, it is characterized in that, this control system also comprises:

Feedforward computing unit, for according to each arm flow of the mixed gas in heating furnace and house steward's flow, calculates feedforward compensation value, and calculates coke-oven gas feedforward amount according to this feedforward compensation value;

Pressure controller exports feedforward computing unit, for according to described coke-oven gas feedforward amount, calculates the pressure controller output valve of band feedforward compensation;

Feedforward coke-oven gas computing unit, for according to described coke-oven gas feedforward amount, carries out band feedforward compensation to described coke-oven gas decoupling computation unit; And

Feedforward blast furnace gas computing unit, for according to described coke-oven gas feedforward amount, carries out band feedforward compensation to the measuring flow of coke-oven gas.

2., for the control method that coal gas blend pressure regulates, the method comprises the steps:

A, mixed once pressure controller, according to mixed once target pressure value and mixed once measured pressure value, calculates pressure controller output valve;

B, according to each arm flow of the mixed gas in heating furnace and house steward's flow, calculates feedforward compensation value, and calculates coke-oven gas feedforward amount according to this feedforward compensation value;

C, according to described coke-oven gas feedforward amount and described pressure controller output valve, calculate the pressure controller output valve of band feedforward compensation, and the coke-oven gas selection unit be delivered in coke gas flow control subloop and blast furnace gas flow control the blast furnace gas selection unit in subloop;

D, according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop, and the coke-oven gas selection unit be delivered in this coke gas flow control subloop, and: according to described coke-oven gas feedforward amount, band feedforward compensation is carried out to the measuring flow of coke-oven gas, and is delivered to the blast furnace gas selection unit in this blast furnace gas flow control subloop;

E, the coke oven controling parameters that coke gas flow controller is determined according to this coke-oven gas selection unit, coke-oven gas variable valve is regulated, and: the selective value that blast furnace gas selection unit is determined calculates through blast furnace gas decoupling computation unit, draw blast furnace controling parameters, blast furnace gas flow controller, according to this blast furnace controling parameters, regulates blast furnace gas variable valve.

3. the control method regulated for coal gas blend pressure according to claim 2, is characterized in that, in described step b, according to each arm flow of the mixed gas in heating furnace and house steward's flow, the formula calculating feedforward compensation value is:

$\mathrm{\ΔX}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{DMDi}}-F_{\mathrm{MG}}+(F_{\mathrm{MG}}-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{F}_{\mathrm{PVi}})\×K_{\mathrm{MG}\_\mathrm{DEV}}+F_{\mathrm{\ΔDEV}};$

In formula, Δ X: feedforward compensation value; heating furnace meets the coal gas total amount required for heat supply; F _mG: the current house steward's flow of mixed gas; mixed gas each arm flow summation in heating furnace; K _{mG_DEV}: mixed gas house steward and arm drift correction coefficient; F _{Δ DEV}: heating furnace and gas station droop modified value; And:

The formula calculating coke-oven gas feedforward amount according to this feedforward compensation value is:

${\mathrm{\ΔX}}_{\mathrm{COG}}=\mathrm{\ΔX}\×(1-R_{\mathrm{LDG}})\×K_{\mathrm{COG}}\×\frac{F_{\mathrm{COG}}}{R_{\mathrm{COG}}\×(F_{\mathrm{COG}}+F_{\mathrm{BFG}})};$

In formula, Δ X _cOG: coke-oven gas feedforward amount; R _lDG: the coal gas of converter total flow range upper limit; K _cOG: correction factor; F _cOG: coke-oven gas total flow measured value; R _cOG: the coke-oven gas total flow range upper limit; F _bFG: blast furnace gas total flow measured value.

4. the control method regulated for coal gas blend pressure according to claim 3, it is characterized in that, in described step c, according to described coke-oven gas feedforward amount and described pressure controller output valve, calculate the pressure controller output valve of band feedforward compensation, computing formula is:

${{\mathrm{OP}}_{\mathrm{COG}}}^{\′}=(\mathrm{OP}+\frac{{\mathrm{\ΔX}}_{\mathrm{COG}}}{R_{\mathrm{COG}}})\×R_{\mathrm{COG}};$

In formula, OP _cOG': the pressure controller output valve of band feedforward compensation; OP: pressure controller output valve.

5. the control method regulated for coal gas blend pressure according to claim 3, is characterized in that, in described steps d, carry out band feedforward compensation, utilize following formula to carry out to the coke-oven gas decoupling computation unit in coke-oven gas flow control subloop:

F(X1)'＝ΔX _COG×K ₃+F(X1)；

Wherein, F (X1) ': the output valve after band feedforward compensation; K ₃: compensating approach coefficient; F (X1): coke-oven gas decoupling computation unit output valve.

6. the control method regulated for coal gas blend pressure according to claim 5, is characterized in that, in described steps d, carry out band feedforward compensation to the measuring flow of coke-oven gas, utilize following formula to carry out:

F(X3)＝ΔX _COG×K ₃+F _COG；

In formula, F (X3) be to the measuring flow band feedforward compensation of coke-oven gas after output valve.