CN101776890B - High-purity control system and method of air separation energy-saving process - Google Patents

Abstract

The invention provides a high-purity control system of an air separation energy-saving process, which comprises an in-site intelligent instrument and a DCS system, wherein the in-site intelligent instrument is directly connected with an air separation tower, the DCS system comprises a storage device, a control station and a host machine, the intelligent instrument is connected with the storage device, the control station is connected with the host machine, the host machine comprises a controller used for solving a control rule and outputting operation variable values, and the controller comprises an ingredient deducing module, a model parameter self-adapting correction module and a high-purity control rule solving module. The invention also provides a high-purity control method of the air separation energy-saving process. The invention provides the high-purity control system and the method of the air separation energy-saving process, which can timely inhabit the interference, can perfectly handle the coupling problem, and have the advantages of good tracking performance, high efficiency and high precision.

Description

A kind of high-purity control system of air-separating energy-saving process and method

Technical field

The present invention relates to the controlling Design field of air-separating energy-saving process, especially, relate to the high-purity control system design and the method for air-separating energy-saving process

Background technology

Be that air is separated empty the branch, obtains the important industry of national economy of high-purity industrial gasses such as oxygen, nitrogen, argon, and its product is widely used in various industrial circles such as oil, chemical industry, metallurgy, electronics, the energy, Aero-Space, food and drink, health care.And huge energy consumption is empty industry-specific bottleneck problem always.

Countries in the world are having dropped into lot of manpower and material resources aspect the energy-conservation research of air separation process, and at the process model building of air separation process, big quantity research has been made in aspects such as advanced control.Since the empty strong nonlinearity that divides distillation process, Complex Dynamic such as coupling, traditional PID controller control, inner membrance control etc. can not meet the demands, and especially in high-purity control field, these controlling schemes are difficult in time follow the tracks of set point change.Though and improved the control effect to a certain extent based on the PREDICTIVE CONTROL scheme of approximately linear model since the approximately linear model can only efficient operation near steady operation point, when the system fluctuation amplitude is bigger, then obviously decline appears in the control system effect.

Summary of the invention

Can not in time suppress to disturb, can not handle preferably coupled problem, tracking performance is poor, efficient is low, precision is low deficiency for what overcome existing empty control system of dividing distillation process, the present invention provides a kind of high-purity control system and method that can in time suppress to disturb, handle preferably coupled problem, tracking performance is good, efficient is high, precision is high air-separating energy-saving process.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of high-purity control system of air-separating energy-saving process; Comprise and direct-connected field intelligent instrument of air separation column and DCS system; Said DCS system comprises memory storage, control station and host computer; Wherein intelligence instrument is connected with memory storage, control station and host computer, and said host computer comprises that said controller comprises in order to find the solution high-purity control law and to export the controller of control variable value:

The component inference module, in order to the detected temperature of intelligence instrument that basis is obtained, pressure data is calculated the concentration of component at each column plate place of tower on the air separation column, and calculating formula is (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\×{\mathrm{\α}}_N\×{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\α}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\×{\mathrm{\α}}_O\×{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\α}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant;

Model parameter adaptively correcting module, in order to the concentration of component data that adopt the component inference module to calculate, the liquid phase component concentration distribution functions of online fitting nitrogen and oxygen, and fitting parameter stored in the middle of the historical data base, suc as formula (3) (4) (5) (6)

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,N}}{1+e^{-k_N(i-S_N)}}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="O"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">O</figure-callout>}}}{1+e^{-k_O(i-S_O)}}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering,

Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, k _N, X _{Min, 0}, X _{Max, 0}, k ₀, β _N, β ₀Be fitting parameter, S _N, S ₀Be the position of air separation column concentration of component distribution curve, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation;

High-purity control rate is found the solution module, and in order to the liquid phase component concentration data according to current nitrogen and oxygen, pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-x_{1,N}\left(k\right))}---\left(11\right)$

${=K}_1({X_{1,N}}^{*}-X_{1,N}\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{1,N}}^{*}-X_{1,N}\left(i\right))T$

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-x_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter is regulated X according to plant characteristic _{1, N}(i) X _{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and rectifying section pressure.

As preferred a kind of scheme: described host computer also comprises human-computer interface module, is used to set sampling period T, the control law parameter K ₁, K ₂, K ₃, K ₄Liquid phase light constituent concentration set point X with nitrogen oxygen at the bottom of the last Tata head tower _{1, N} ^*, X _{N, O} ^*, and the curve of output of display controller and controlled variable are the recording curve of liquid phase light constituent concentration at the bottom of the cat head tower.

Further, said intelligence instrument is connected with said data-interface, and said data-interface is connected with data bus, and said host computer, memory storage and control station all are connected with data bus.

A kind of high-purity control method of air-separating energy-saving process, described high-purity control method may further comprise the steps:

1) confirm sampling period T, and with the T value, nitrogen and oxygen is with respect to the relative volatility α of argon _N, α _O, Anthony constant a _N, b _N, c _N, a _O, b _O, c _OBe kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄Liquid phase light constituent concentration set point X with nitrogen oxygen at the bottom of the last Tata head tower _{1, N} ^*, X _{N, O} ^*

3) detect tower pressure P (k) in the k sampling instant, each column plate temperature T _i(k), calculate the concentration of component value of liquid nitrogen liquid oxygen, calculating formula is suc as formula (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_N\&times;{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\&alpha;}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_O\&times;{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\&alpha;}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant;

And liquid phase stream value at the bottom of detection k sampling instant overhead gas phase flow rate and the tower, with tower pressure data on the air separation column, each column plate temperature data, the measured value of concentration of component store in the middle of the historical data base of observer system together;

4) adopt the concentration of component data that step 3) calculates in the historical data base, online fitting pattern function, and fitting parameter stored in the middle of the historical data base, fitting function are suc as formula (3) to formula (6):

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,N}}{1+e^{-k_N(i-S_N)}}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="O"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">O</figure-callout>}}}{1+e^{-k_O(i-S_O)}}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering,

Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, k _N, X _{Min, 0}, X _{Max, 0}, k ₀, β _N, β ₀Be fitting parameter, S _N, S ₀Be the position of tower concentration of component distribution curve on the air separation column, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation;

5) according to the liquid phase component concentration data of current nitrogen and oxygen, pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-x_{1,N}\left(k\right))}---\left(11\right)$

${=K}_1({X_{1,N}}^{*}-X_{1,N}\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{1,N}}^{*}-X_{1,N}\left(i\right))T$

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-x_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter is regulated X according to plant characteristic _{1, N}(i) X _{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and rectifying section pressure;

6) control variable with the current time air-separating energy-saving process is the current desirable change value Δ q (k) of feed heat situation and last tower pressure, and Δ P (k) flows to the control station in the DCS system, the feed heat condition and the last tower pressure values of adjustment air-separating energy-saving process.

Further; Described historical data base is a memory storage in the DCS system, and intelligence instrument is connected with said data-interface, and said data-interface is connected with data bus; Said host computer, memory storage and control station all are connected with data bus; In the said control station, read historical data base, show the duty of air-separating energy-saving process.

Beneficial effect of the present invention mainly shows: 1, high-purity controlling schemes is based upon on the high precision nonlinear dynamic model basis, can in time suppress interference effect; 2, controlling schemes has been handled coupled problem preferably, can follow the tracks of set point change rapidly and accurately; 3, efficient is high, precision is high.

Description of drawings

Fig. 1 is the high-purity control system structural drawing of air-separating energy-saving process proposed by the invention

Fig. 2 is the schematic diagram of supervisory controller implementation method

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

Embodiment 1

With reference to Fig. 1, a kind of high-purity control system of air-separating energy-saving process, comprise with the direct-connected field intelligent instrument of air separation column 12, DCS system in memory storage 4; Control station 5 and host computer 6, wherein intelligence instrument 2, memory storage 4, control station 5 links to each other with host computer 6 successively; It is characterized in that the high-purity controller function of host computer 6 realizations; Find the solution high-purity control law, output control variable change value, described controller comprises the component inference module; Model parameter adaptively correcting module, high-purity control rate of air-separating energy-saving process is found the solution module;

Described component inference module 9 is characterized in that host computer 6 obtains intelligence instrument 2 detected temperature, and pressure data is calculated the concentration of component at each column plate place of tower on the air separation column, and calculating formula is (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_N\&times;{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\&alpha;}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_O\&times;{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\&alpha;}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant.

The concentration of component data that described model parameter adaptively correcting module 10 adopts the component inference modules to calculate, the liquid phase component concentration distribution functions of online fitting nitrogen and oxygen, and fitting parameter stored in the middle of the historical data base, suc as formula (3) (4) (5) (6)

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">N</figure-callout>}}}{1+e^{-k_N(i-S_N)}}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="O"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">O</figure-callout>}}}{1+e^{-k_O(i-S_O)}}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering, Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, k _N, X _{Min, 0}, X _{Max, 0}, k ₀, β _N, β ₀Be fitting parameter, S _N, S ₀Be the position of air separation column concentration of component distribution curve, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation.

High-purity control rate of described air-separating energy-saving process is found the solution the liquid phase component concentration data of module 11 according to current nitrogen and oxygen; Pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">x</figure-callout>}}_{1,N}\left(k\right))}---\left(11\right)$

${=K}_1({{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}}^{*}-{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}\left(k\right))+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}}^{*}-{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}\left(i\right))T$

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">x</figure-callout>}}_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter is regulated X according to plant characteristic _{1, N}(i) X _{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and rectifying section pressure.

Described host computer 6 comprises human-computer interface module 12, is used to set sampling period T, the control law parameter K ₁, K ₂, K ₃, K ₄Liquid phase light constituent concentration set point X with nitrogen oxygen at the bottom of the last Tata head tower _{1, N} ^*, X _{N, O} ^*, and the curve of output of display controller and controlled variable are the recording curve of liquid phase light constituent concentration at the bottom of the cat head tower;

Air separation column 1 is connected with intelligence instrument 2, and intelligence instrument 2 is connected with said data-interface 3, and said data-interface 3 is connected with data bus, and said host computer 6, memory storage 4 all are connected with data bus with control station 5.

Embodiment 2

See figures.1.and.2, a kind of high-purity control method of air-separating energy-saving process, described control method may further comprise the steps:

1) confirm sampling period T, and with the T value, nitrogen and oxygen is with respect to the relative volatility α of argon _N, α _O, Anthony constant a _N, b _N, c _N, a _O, b _O, c _OBe kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄Liquid phase light constituent concentration set point X with nitrogen oxygen at the bottom of the last Tata head tower _{1, N} ^*, X _{N, O} ^*

3) detect tower pressure P (k) in the k sampling instant, each column plate temperature T _i(k), calculate the concentration of component value of liquid nitrogen liquid oxygen, calculating formula is suc as formula (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_N\&times;{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\&alpha;}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_O\&times;{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\&alpha;}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant.

And liquid phase stream value at the bottom of detection k sampling instant overhead gas phase flow rate and the tower, with tower pressure data on the air separation column, each column plate temperature data, the measured value of concentration of component store in the middle of the historical data base of observer system together;

4) adopt the concentration of component data that step 3) calculates in the historical data base, online fitting pattern function, and fitting parameter stored in the middle of the historical data base, fitting function are suc as formula (3) to formula (6):

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">N</figure-callout>}}}{1+e^{-k_N(i-S_N)}}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,\mathrm{<figure-callout\; id="1"\; label="O"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">O</figure-callout>}}}{1+e^{-k_O(i-S_O)}}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering,

Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, k _N, X _{Min, 0}, X _{Max, 0}, k ₀, β _N, β ₀Be fitting parameter, S _N, S ₀Be the position of air separation column concentration of component distribution curve, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation.

5) according to the liquid phase component concentration data of current nitrogen and oxygen, pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">x</figure-callout>}}_{1,N}\left(k\right))}---\left(11\right)$

${=K}_1({{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}}^{*}-{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}\left(k\right))+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}}^{*}-{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">X</figure-callout>}}_{1,N}\left(i\right))T$

$\frac{{-V}_1\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">x</figure-callout>}}_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="H2009101555637E00011.png"\; state="\{\{state\}\}">K</figure-callout>}}_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter is regulated X according to plant characteristic ^{1, N}(i) X ^{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and rectifying section pressure;

6) control variable with the current time air-separating energy-saving process is the current desirable change value Δ q (k) of feed heat situation and last tower pressure, and Δ P (k) flows to the control station 5 in the DCS system, the feed heat condition and the last tower pressure values of adjustment air separation energy saving.

Air separation column 1 is connected with intelligence instrument 2, and intelligence instrument 2 is connected with said data-interface 3, and said data-interface 3 is connected with data bus, and said host computer 6, memory storage 4 all are connected with data bus with control station 5.

Described historical data base is a memory storage 4 in the DCS system, and described DCS system comprises data-interface 3, memory storage 4, and control station 5, wherein control station can read historical data base, shows the duty of air-separating energy-saving process.

Claims (5)

1. the high-purity control system of an air-separating energy-saving process; Comprise and direct-connected field intelligent instrument of air separation column and DCS system; Said DCS system comprises memory storage, control station and host computer; Wherein intelligence instrument is connected with memory storage, control station and host computer, it is characterized in that: said host computer comprises that said controller comprises in order to find the solution high-purity control law and to export the controller of control variable value:

The component inference module, in order to the detected temperature of intelligence instrument that basis is obtained, pressure data is calculated the concentration of component at each column plate place of tower on the air separation column, and calculating formula is (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_N\&times;{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\&alpha;}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_O\&times;{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\&alpha;}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant;

Model parameter adaptively correcting module, in order to the concentration of component data that adopt the component inference module to calculate, the liquid phase component concentration distribution functions of online fitting nitrogen and oxygen, and fitting parameter stored in the middle of the historical data base, suc as formula (3) (4) (5) (6)

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,N}}{1+e^{{-k}_N}(i-S_N)}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,O}}{1+e^{{-k}_O}(i-S_O)}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering,

Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, K _N, X _{Min, O}, X _{Max, O}, k _O, β _N, β _OBe fitting parameter, S _N, S _OBe the position of air separation column concentration of component distribution curve, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation;

High-purity control rate is found the solution module, and in order to the liquid phase component concentration data according to current nitrogen and oxygen, pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

$y_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

$y_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{-V_1\left(k\right)y_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-x_{1,N}\left(k\right))}---\left(11\right)$

$=K_1({X_{1,N}}^{*}-X_{1,N}\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{1,N}}^{*}-X_{1,N}\left(i\right))T$

$\frac{-V_1\left(k\right)y_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-x_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter, regulate X according to plant characteristic _{1, N}(i), X _{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and rectifying section pressure.

2. the high-purity control system of a kind of air-separating energy-saving process as claimed in claim 1, it is characterized in that: described host computer also comprises human-computer interface module, is used to set sampling period T, the control law parameter K ₁, K ₂, K ₃, K ₄With last column overhead nitrogen vapour-liquid phase concentration setting value X _{1, N} ^*, oxygen vapour-liquid phase concentration setting value X at the bottom of the tower _{N, O} ^*, and the curve of output of display controller and controlled variable are the recording curve of the liquid phase component concentration of oxygen at the bottom of the liquid phase component concentration, tower of cat head nitrogen.

3. according to claim 1 or claim 2 a kind of high-purity control system of air-separating energy-saving process; It is characterized in that: said intelligence instrument is connected with data-interface; Said data-interface is connected with data bus, and said host computer, memory storage and control station all are connected with data bus.

4. high-purity control method of realizing of the high-purity control system of an air-separating energy-saving process as claimed in claim 1, it is characterized in that: described high-purity control method may further comprise the steps:

1) confirm sampling period T, and with the T value, nitrogen and oxygen is with respect to the relative volatility α of argon _N, α _O, Anthony constant a _N, b _N, c _N, a _O, b _O, c _OBe kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄With last column overhead nitrogen vapour-liquid phase concentration setting value X _{1, N} ^*, oxygen vapour-liquid phase concentration setting value X at the bottom of the tower _{N, O} ^*

3) detect tower pressure P (k) in the k sampling instant, each column plate temperature T _i(k), calculate the concentration of component value of liquid nitrogen liquid oxygen, calculating formula is suc as formula (1) (2):

$X_{i,N}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_N\&times;{10}^{(\frac{T_i\left(k\right)+c_N}{b_N}-a_N)}-1}{{\mathrm{\&alpha;}}_N-1}---\left(1\right)$

$X_{i,O}\left(k\right)=\frac{P\left(k\right)\&times;{\mathrm{\&alpha;}}_O\&times;{10}^{(\frac{T_i\left(k\right)+c_O}{b_O}-a_O)}-1}{{\mathrm{\&alpha;}}_O-1}---\left(2\right)$

Wherein k is current sampling instant, X _{I, N}(k) be the liquid phase component concentration of tower i piece column plate place nitrogen on the k sampling instant air separation column, X _{I, O}(k) be the liquid phase component concentration of tower i piece column plate place oxygen on the k sampling instant air separation column, P (k) is a tower pressure on the k sampling instant air separation column, T _i(k) be the temperature at each piece column plate place of tower on the k sampling instant air separation column, α _N, α _OBe respectively nitrogen and oxygen relative volatility, a with respect to argon _N, b _N, c _N, a _O, b _O, c _OBe the Anthony constant;

And liquid phase stream value at the bottom of detection k sampling instant overhead gas phase flow rate and the tower, with tower pressure data on the air separation column, each column plate temperature data, the measured value of concentration of component store in the middle of the historical data base of observer system together;

4) adopt the concentration of component data that step 3) calculates in the historical data base, online fitting pattern function, and fitting parameter stored in the middle of the historical data base, fitting function are suc as formula (3) to formula (6):

${\hat{X}}_{i,N}=X_{\min ,N}+\frac{X_{\max ,N}-X_{\min ,N}}{1+e^{{-k}_N}(i-S_N)}---\left(3\right)$

${\hat{X}}_{i,O}=X_{\min ,O}+\frac{X_{\max ,O}-X_{\min ,O}}{1+e^{{-k}_O}(i-S_O)}---\left(4\right)$

S _N＝β _NP ² (5)

S _O＝β _Oq ² (6)

Wherein i is the column plate numbering,

Be respectively the liquid concentration of estimating of estimating liquid concentration and oxygen of i piece column plate place nitrogen, X _{Min, N}, X _{Max, N}, k _N, X _{Min, O}, X _{Max, O}, k _O, β _N, β _OBe fitting parameter, S _N, S _OBe the position of tower concentration of component distribution curve on the air separation column, P is a tower pressure under the air separation column, and q is an air separation column feed heat situation;

5) according to the liquid phase component concentration data of current nitrogen and oxygen, pattern function and current time performance variable value are asked for the ideal change value of current control variable, find the solution the control law Algebraic Equation set suc as formula (7) to formula (12)

$y_{1,N}\left(k\right)=\frac{{\mathrm{\&alpha;}}_N{x}_{1,N}\left(k\right)}{({\mathrm{\&alpha;}}_N-1)x_{1,N}\left(k\right)+1}---\left(7\right)$

$y_{1,O}\left(k\right)=\frac{{\mathrm{\&alpha;}}_O{x}_{1,O}\left(k\right)}{({\mathrm{\&alpha;}}_O-1)x_{1,O}\left(k\right)+1}---\left(8\right)$

S _N(k)＝β _N(P(k)+ΔP(k)) ² (9)

S _O(k)＝β _O(q(k)+Δq(k)) ² (10)

$\frac{-V_1\left(k\right)y_{1,N}\left(k\right)-L_n\left(k\right)x_{n,N}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,N}\left(k\right)}{M(x_{n,N}\left(k\right)-x_{1,N}\left(k\right))}---\left(11\right)$

$=K_1({X_{1,N}}^{*}-X_{1,N}\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{1,N}}^{*}-X_{1,N}\left(i\right))T$

$\frac{-V_1\left(k\right)y_{1,O}\left(k\right)-L_n\left(k\right)x_{n,O}\left(k\right)+\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{F}_i\left(k\right){x^f}_{i,O}\left(k\right)}{M(x_{n,O}\left(k\right)-x_{1,O}\left(k\right))}---\left(12\right)$

$=K_3({X_{n,O}}^{*}-X_{n,O}\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}({X_{n,O}}^{*}-X_{n,O}\left(i\right))T$

Wherein k is current sampling instant, and subscript i is the column plate numbering, and 1 is the cat head numbering, and n is the numbering at the bottom of the tower, and subscript N, O represent nitrogen and oxygen respectively, and superscript f represents charging, F _i(k) be i piece column plate feed rate, L _n(k) liquid phase flow rate at the bottom of the tower, V ₁(k) be respectively cat head gas phase flow rate, x _{N, N}(k), x _{N, O}(k) be respectively the concentration of component of liquid nitrogen liquid oxygen at the bottom of the tower, y _{1, N}(k), y _{1, O}(k) be respectively cat head vapour nitrogen vapour oxygen concentration of component, x ^f _{I, N}(k), x ^f _{I, O}(k) be respectively the charging liquid nitrogen concentration of component and the charging liquid oxygen concentration of component of i piece column plate, M is the column plate liquid holdup, X _{1, N} ^*, X _{N, O} ^*Be respectively oxygen vapour-liquid phase concentration setting value at the bottom of column overhead nitrogen vapour-liquid phase concentration setting value and the tower, K ₁, K ₂, K ₃, K ₄For the control law parameter, regulate X according to plant characteristic _{1, N}(i), X _{N, O}Engrave the liquid phase component concentration of oxygen at the bottom of liquid phase component concentration and the tower of column overhead nitrogen when (i) being respectively i, the control variable that Δ q (k), Δ P (k) are respectively the current time air-separating energy-saving process is the current desirable change value of feed heat situation and last tower pressure;

6) control variable with the current time air-separating energy-saving process is the current desirable change value Δ q (k) of feed heat situation and last tower pressure, and Δ P (k) flows to the control station in the DCS system, the feed heat condition and the last tower pressure values of adjustment air-separating energy-saving process.

5. high-purity control method as claimed in claim 4; It is characterized in that: described historical data base is a memory storage in the DCS system, and intelligence instrument is connected with data-interface, and said data-interface is connected with data bus; Said host computer, memory storage and control station all are connected with data bus; In the said control station, read historical data base, show the duty of air-separating energy-saving process.

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