CN111637633A - Control method for constant-temperature backwater of solid regenerative furnace - Google Patents

Abstract

A control method for constant-temperature backwater of a solid regenerative furnace relates to the technical field of automatic control of the solid regenerative furnace, and comprises the following steps: the backwater temperature is a set value, an ideal outlet water temperature value changing in real time is calculated through an empirical equation, the outlet water temperature can be accurately controlled through single-stage or two-stage PID adjustment, and the constant temperature backwater is achieved by controlling the outlet water temperature changing in real time. The invention has the beneficial effects that: the method comprises the steps of responding to the change of the environment temperature in time, calculating an outlet water temperature value needing to maintain constant return water temperature as a set value, automatically adjusting according to the calculated outlet water temperature, enabling the return water temperature to be basically constant near the set value, enabling the heat storage furnace to stably release heat, avoiding the occurrence of a fan sudden stop and sudden start state, enabling the constant return water temperature to be the set value, enabling the overshoot to be plus or minus 0.5 ℃, and enabling the heat storage furnace to stably release heat, namely saving energy and stabilizing the return water temperature.

Description

Control method for constant-temperature backwater of solid regenerative furnace

Technical Field

The invention relates to the technical field of automatic control of solid regenerative furnaces, in particular to a control method for constant-temperature backwater of a solid regenerative furnace.

Background

At present, on the premise of meeting the heat supply requirement, a heat supply system of a regenerative furnace is required to maintain the return water temperature of the heat supply system to be stable within a set range or return water at a constant temperature in order to achieve the effect of energy conservation and avoid adverse conditions that the room temperature of front-end and high-rise heat users is too high and the room temperature of end users is too low. However, because the heating system has slow response and overlong cycle period, which is generally over half an hour, the ideal constant-temperature backwater heating cannot be realized by the existing automatic control method.

Disclosure of Invention

Aiming at the defects of the prior art, the method considers that when the working conditions such as the ambient temperature and the like are not changed, the equation relation exists between the water outlet temperature, the backwater temperature and the ambient temperature when the time is similar (the solar radiation change is not large) for a heat supply system and a heat supply object, the relation curve equation can be obtained through calculation by a mathematical method, the water outlet temperature can be accurately controlled through single-stage or two-stage PID adjustment, and the goal of constant temperature backwater can be achieved through controlling the water outlet temperature which changes in real time.

The invention provides a control method for constant-temperature backwater of a solid regenerative furnace, which considers that the outlet water temperature of furnace water has main influence on the backwater temperature, the backwater temperature is a set value, an ideal outlet water temperature value changing in real time is calculated through an empirical equation, the outlet water temperature can be accurately controlled through single-stage or two-stage PID regulation, and the constant-temperature backwater is achieved by controlling the outlet water temperature changing in real time;

the equation:

T_{go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}

Wherein a, b, c and d are numbers to be solved under different working conditions;

T_{go out}The temperature of the water is indicated;

T_{go back to}The set backwater temperature is a set value;

T_{ring (C)}Processing value of the ambient temperature, T_{Ring (C)}= (= (environmental measurement + 50)/10;

f indicates the measured water flow.

The calculation method of the equation is as follows:

the circulating water pump of the heating system is a power frequency pump, and is regarded as unchanged when no flow is detected

（T_{Go out}—T_{Go back to}）F=aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d

Let Y = (T)_{Go out}—T_{Go back to}）F；

Ｘ＝Ｔ_{A ring;}

Ｙ＝aＸ³+bＸ²+cＸ+d；

taking 4 groups of data:

the water flow rate and the length of a heating circulation pipe are known, the time of water circulation for one circle can be calculated, the value can be set according to the actual working condition and can also be estimated according to the actual working condition, and the circulation period is used for obtaining the value time points of the water outlet temperature and the environment temperature;

T_{go back to}Taking data every 1 minute from the current time, and taking 4 groups of data; t is_{Go out}、T_{Ring (C)}The data fetching time is the time obtained by subtracting the cycle period from the current time, and then the data is fetched every 1 minute, and 4 groups of data are fetched; the 4 groups of data are used for automatically solving equations a, b, c and d to obtain an equation, and the T is calculated by the equation and the current ambient temperature_{Go out}And (4) the outlet water temperature value.

The concrete solving method of the equation comprises the following steps:

take 4 sets of data records as (x)₁、y₁），（x₂、y₂），（x₃、y₃），（x₄、y₄）

y₁=ax₁ ³+ bx₁ ²+ cx₁+ d formula 1-1

y₂=ax₂ ³+ bx₂ ²+ cx₂+ d formula 1-2

y₃=ax₃ ³+ bx₃ ²+ cx₃+ d formula 1-3

y₄=ax₄ ³+ bx₄ ²+ cx₄+ d formula 1-4

1-1, 1-2, 1-3, 1-4, or d:

y₁—y₂=（x₁ ³—x₂ ³）a+（x₁ ²—x₂ ²）b+（x₁—x₂) c formula 2-1

y₂—y₃=（x₂ ³—x₃ ³）a+（x₂ ²—x₃ ²）b+（x₂—x₃) c formula 2-2

y₃—y₄=（x₃ ³—x₄ ³）a+（x₃ ²—x₄ ²）b+（x₃—x₄) c formula 2-3

Removing C and solving to obtain:

(y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃)= (x₁ ²+ x₁x₂— x₁x₃—x₃ ²)a+(x₁—x₃)b

(y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄)= (x₂ ²+ x₂x₃— x₃x₄—x₄ ²)a+(x₂—x₄)b

b is removed, and the solution is obtained:

a=((y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃))/（x₁— x₃）（x₁— x₄）—((y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄))/（x₂— x₄）（x₁— x₄）；

the result is brought into a formula C to obtain a b value;

as a result, the band reaches the value of c in the formula 2-1;

the result is carried into formula 1-1 to obtain the d value;

solving the values of a, b, c and d by 4 recorded values according to the curve equation;

substituting the values of a, b, c, d into the formula: t is_{Go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}And obtaining the temperature of the effluent.

The invention has the beneficial effects that: the method comprises the steps of responding to the change of the environment temperature in time, calculating an outlet water temperature value needing to maintain constant return water temperature as a set value, automatically adjusting according to the calculated outlet water temperature, enabling the return water temperature to be basically constant near the set value, enabling the heat storage furnace to stably release heat, avoiding the occurrence of a fan sudden stop and sudden start state, enabling the constant return water temperature to be the set value, enabling the overshoot to be plus or minus 0.5 ℃, and enabling the heat storage furnace to stably release heat, namely saving energy and stabilizing the return water temperature.

Drawings

FIG. 1 shows the outlet water temperature and the return water temperature controlled during actual continuous operation;

fig. 2 shows the outlet water temperature and the return water temperature controlled during actual intermittent operation.

Detailed Description

Embodiment 1, as shown in fig. 1 to 2, the present invention provides a method for controlling constant temperature backwater of a solid regenerator, where a backwater temperature is a set value, an ideal outlet water temperature value changing in real time is calculated by an empirical equation, the outlet water temperature can be accurately controlled by single-stage or two-stage PID adjustment, and the constant temperature backwater is achieved by controlling the outlet water temperature changing in real time;

the equation:

T_{go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}

Wherein a, b, c and d are numbers to be solved under different working conditions;

T_{go out}The temperature of the water is indicated;

T_{go back to}The set backwater temperature is a set value;

T_{ring (C)}Processing value of the ambient temperature, T_{Ring (C)}= (= (environmental measurement + 50)/10;

f indicates the measured water flow.

The calculation method of the equation is as follows:

the circulating water pump of the heating system is a power frequency pump, and is regarded as unchanged when no flow is detected

（T_{Go out}—T_{Go back to}）F=aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d

Let Y = (T)_{Go out}—T_{Go back to}）F；

Ｘ＝Ｔ_{A ring;}

Ｙ＝aＸ³+bＸ²+cＸ+d；

taking 4 groups of data:

the water flow rate and the length of a heating circulation pipe are known, the time of water circulation for one circle can be calculated, the value can be set according to the actual working condition and can also be estimated according to the actual working condition, and the circulation period is used for obtaining the value time points of the water outlet temperature and the environment temperature;

T_{go back to}Taking data every 1 minute from the current time, and taking 4 groups of data; t is_{Go out}、T_{Ring (C)}The data fetching time is the time obtained by subtracting the cycle period from the current time, and then the data is fetched every 1 minute, and 4 groups of data are fetched; the 4 groups of data are used for automatically solving equations a, b, c and d to obtain an equation, and the T is calculated by the equation and the current ambient temperature_{Go out}And (4) the outlet water temperature value.

The concrete solving method of the equation comprises the following steps:

take 4 sets of data records as (x)₁、y₁），（x₂、y₂），（x₃、y₃），（x₄、y₄）

y₁=ax₁ ³+ bx₁ ²+ cx₁+ d formula 1-1

y₂=ax₂ ³+ bx₂ ²+ cx₂+ d formula 1-2

y₃=ax₃ ³+ bx₃ ²+ cx₃+ d formula 1-3

y₄=ax₄ ³+ bx₄ ²+ cx₄+ d formula 1-4

1-1, 1-2, 1-3, 1-4, or d:

y₁—y₂=（x₁ ³— x₂ ³）a+（x₁ ²— x₂ ²）b+（x₁— x₂) c formula 2-1

y₂—y₃=（x₂ ³— x₃ ³）a+（x₂ ²— x₃ ²）b+（x₂— x₃) c formula 2-2

y₃—y₄=（x₃ ³— x₄ ³）a+（x₃ ²— x₄ ²）b+（x₃— x₄) c formula 2-3

Removing C and solving to obtain:

(y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃)= (x₁ ²+ x₁x₂— x₁x₃—x₃ ²)a+(x₁—x₃)b

(y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄)= (x₂ ²+ x₂x₃— x₃x₄—x₄ ²)a+(x₂—x₄)b

b is removed, and the solution is obtained:

a=((y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃))/（x₁— x₃）（x₁— x₄）—((y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄))/（x₂— x₄）（x₁— x₄）；

the result is brought into a formula C to obtain a b value;

as a result, the band reaches the value of c in the formula 2-1;

the result is carried into formula 1-1 to obtain the d value;

solving the values of a, b, c and d by 4 recorded values according to the curve equation;

substituting the values of a, b, c, d into the formula: t is_{Go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}And obtaining the temperature of the effluent.

2 heat storage furnaces of 2MW in a certain heating station adopt a control method of controlling constant return water temperature by variable outlet temperature in automatic control logic, the return water temperature is fed back to change about 30 minutes after the circulating water is discharged, the water circulation period is about 30 minutes, and the flow is not changed. The method comprises the following steps of calculating a certain time, namely taking a water outlet temperature value, an environment temperature value and a water return temperature value after 30 minutes, taking 1 numerical value every 10 seconds, taking 4 groups of numerical values, automatically solving an equation through mathematics, and recording a formula after 30 minutes and 40 seconds of a certain time as follows:

T_{go out}=0.013T_{Ring (C)} ³—0.171T_{Ring (C)} ²—3.210T_{Ring (C)}+18.570+ T_{Go back to}

At this time, the ambient temperature is-19 ℃ and T_{Ring (C)}=（50—19）/10=3.1

The set value of the backwater temperature is 40 ℃ and T_{Go back to}=40

T_{Go out}=—0.013×3.1³—0.171×3.1²—3.210×3.1+18.570+T_{Go back to}

T_{Go out}=46.6

The temperature of the outlet water is 44.6 DEG C

After 40 seconds the equation is generated:

T_{go out}=—0.013T_{Ring (C)} ³—0.17 1T_{Ring (C)} ²— 3.010T_{Ring (C)}+18.01+ T_{Go back to}

At this time, the ambient temperature is-18.6 ℃ and T_{Go out}=46.5℃

The water outlet temperature and the water return temperature are controlled during actual continuous operation as shown in fig. 1.

By varying the outlet temperature, the return water temperature is maintained substantially constant.

The water outlet temperature and the water return temperature are controlled during actual discontinuous operation as shown in fig. 2.

By changing the outlet temperature, the return water temperature is kept substantially constant when the regenerator is full for 1 cycle.

Claims (3)

1. A control method for constant-temperature backwater of a solid regenerative furnace is characterized by comprising the following steps: the backwater temperature is a set value, an ideal outlet water temperature value changing in real time is calculated through an empirical equation, the outlet water temperature can be accurately controlled through single-stage or two-stage PID adjustment, and the outlet water temperature changing in real time is controlled to reach constant temperature backwater;

the equation:

T_{go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}

Wherein a, b, c and d are numbers to be solved under different working conditions;

T_{go out}The temperature of the water is indicated;

T_{go back to}The set backwater temperature is a set value;

T_{ring (C)}Processing value T of environmental temperature_{Ring (C)}= (= (environmental measurement + 50)/10;

f indicates the measured water flow.

2. The method for controlling the constant-temperature backwater of the solid regenerative furnace according to claim 1, wherein the method comprises the following steps: the calculation method of the equation is as follows:

the circulating water pump of the heating system is a power frequency pump, and is regarded as unchanged when no flow is detected

（T_{Go out}—T_{Go back to}）F=aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d

Let Y = (T)_{Go out}—T_{Go back to}）F；

Ｘ＝Ｔ_{A ring;}

Ｙ＝aＸ³+bＸ²+cＸ+d；

taking 4 groups of data:

the water flow and the length of a heating circulation pipe are known, the time of water circulation for one week can be calculated, the backwater temperature value can be set according to the actual working condition or estimated according to the actual working condition, and the circulation period is used for obtaining the value time points of the effluent temperature and the environment temperature;

T_{go back to}Taking data every 1 minute from the current time, and taking 4 groups of data; t is_{Go out}、T_{Ring (C)}The data fetching time is the time obtained by subtracting the cycle period from the current time, and then the data is fetched every 1 minute, and 4 groups of data are fetched; the 4 groups of data are used for automatically solving equations a, b, c and d to obtain an equation, and the T is calculated by the equation and the current ambient temperature_{Go out}And (4) the outlet water temperature value.

3. The method for controlling the constant-temperature backwater of the solid regenerative furnace according to claim 2, wherein the method comprises the following steps: the concrete solving method of the equation comprises the following steps:

take 4 sets of data records as (x)₁、y₁），（x₂、y₂），（x₃、y₃），（x₄、y₄）

y₁=ax₁ ³+ bx₁ ²+ cx₁+ d formula 1-1

y₂=ax₂ ³+ bx₂ ²+ cx₂+ d formula 1-2

y₃=ax₃ ³+ bx₃ ²+ cx₃+ d formula 1-3

y₄=ax₄ ³+ bx₄ ²+ cx₄+ d formula 1-4

1-1, 1-2, 1-3, 1-4, or d:

y₁—y₂=（x₁ ³— x₂ ³）a+（x₁ ²— x₂ ²）b+（x₁— x₂) c formula 2-1

y₂—y₃=（x₂ ³— x₃ ³）a+（x₂ ²— x₃ ²）b+（x₂— x₃) c formula 2-2

y₃—y₄=（x₃ ³— x₄ ³）a+（x₃ ²— x₄ ²）b+（x₃— x₄) c formula 2-3

Removing C and solving to obtain:

(y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃)= (x₁ ²+ x₁x₂— x₁x₃—x₃ ²)a+(x₁—x₃)b

(y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄)= (x₂ ²+ x₂x₃— x₃x₄—x₄ ²)a+(x₂—x₄)b

b is removed, and the solution is obtained:

a=((y₁—y₂)/(x₁—x₂)— (y₂—y₃)/(x₂—x₃))/（x₁— x₃）（x₁— x₄）—((y₂—y₃)/(x₂—x₃)— (y₃—y₄)/(x₃—x₄))/（x₂— x₄）（x₁— x₄）；

the result is brought into a formula C to obtain a b value;

as a result, the band reaches the value of c in the formula 2-1;

the result is carried into formula 1-1 to obtain the d value;

solving the values of a, b, c and d by 4 recorded values according to the curve equation;

substituting the values of a, b, c, d into the formula: t is_{Go out}=（aT_{Ring (C)} ³+bT_{Ring (C)} ²+cT_{Ring (C)}+d）/F+T_{Go back to}And obtaining the temperature of the effluent.

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