CN101708379B - System for high purity control in high-efficiency energy-saving rectifying process and method thereof - Google Patents

Abstract

The invention relates to a system for the high purity control in a high-efficiency energy-saving rectifying process. The system comprises a field intelligent instrument and a DCS system which are connected with a high-efficiency energy-saving rectifying tower, wherein the DCS system comprises a storage device, a control station and an upper computer, the upper computer includes a high purity controller used for calculating and outputting the control variable values of the high-efficiency energy-saving rectifying tower. The high purity controller comprises a component inferring module, a model parameter self-adaptation correcting and fitting module and a high purity control law solving module in the high-efficiency energy-saving rectifying process, wherein the component inferring module is used for acquiring temperature and pressure data from the intelligent instrument and calculating the component concentration of each tower plate of the high-efficiency energy-saving rectifying tower, the model parameter self-adaptation correcting and fitting module is used for on-line fitting model functions by using component concentration data calculated by the component inferring module in a historical database, and the high purity control law solving module in the high-efficiency energy-saving rectifying process is used for achieving the ideal change value of the current control variable based on the current component concentration data, the model functions and current operation variable values. The invention also provides a high purity control method. The invention has the advantages of good control effect and ideal control quality.

Description

A kind of high-purity control system of energy-efficient distillation process and method

Technical field

The present invention relates to rectifying control field, especially proposed a kind of high-purity control system and method for energy-efficient distillation process.

Background technology

Distillation process is a kind of core process in the chemical process, and rectifying column is one of them essential elements.For a long time, rectifying column is because of highly energy-consuming, and the problem of low efficiency becomes the focus of international rectifying area research.Mainly contain the solution of two aspects at present at the energy consumption problem of distillation process: a kind of design new structure, utilize the heat coupling to realize that the energy recycling reaches energy-conservation purpose, a kind of design highly efficient distilling process control strategy reaches energy-conservation purpose thereby improve production quality minimizing waste material.Although there is more experimental study to prove that energy-efficient rectifying column can significantly improve energy utilization rate, but owing to exist extremely strong coupling and this tower to have very complicated strong nonlinearity between the rectifying section of energy-efficient rectifying column and the stripping section, the control strategy design of this tower seems particularly difficult.

Traditional PID, internal model control scheme etc. can not satisfy the control quality requirements of energy-efficient distillation process, and especially in the middle of the high-purity distillation process control, these schemes have been difficult to make distillation process stable.And can only be operated near the steady operation point based on the PREDICTIVE CONTROL scheme of linear Identification model, increase interference magnitude a little, perhaps set value step change system control quality and obvious decline then occurs.The fact shows: the key link that the effective high-purity control scheme that designs effective highly efficient distilling process is the quiet run of highly efficient distilling process.

Summary of the invention

, control quality unfavorable deficiency bad for the control effect that overcomes present highly efficient distilling process the invention provides a kind of high-purity control system and method for controlling the energy-efficient distillation process respond well, that the control quality is desirable.

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

A kind of high-purity control system of energy-efficient distillation process, comprise and direct-connected field intelligent instrument of energy-efficient rectifying column and DCS system, described DCS system comprises storage device, control station and host computer, field intelligent instrument is connected with storage device, control station and host computer, described host computer comprises that described high-purity controller comprises in order to calculate high-purity controller of the energy-efficient rectifying column control variables value of output:

The component inference module, in order to obtaining temperature from intelligence instrument, pressure data is calculated the concentration of component of each piece column plate of energy-efficient rectifying column, and concentration of component result of calculation is stored in the middle of the historical data base, and calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=\mathrm{1,2},......,f-1---\left(1\right)$

$X_i\left(k\right)=\frac{P_s\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=f,f+1,......,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and 1 is the cat head numbering, and f is the feedboard numbering, and n numbers X at the bottom of for tower _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and α, b, c are the Anthony constant.

Model parameter adaptively correcting fitting module, in order to adopting the concentration of component data that the component inference module 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) (4):

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}}i=\mathrm{1,2},......,f-1---\left(3\right)$

${\hat{X}}_i=X_{\min ,s}+\frac{X_{\max ,s}-X_{\min ,s}}{1+e^{-k_s(i-S_s)}}i=f,f+1,......,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, k _r, X _{Min, s}, X _{Max, s}, k _sBe fitting parameter, S _r, S _sBe respectively the position of energy-efficient rectifying column rectifying section, stripping section liquid phase component CONCENTRATION DISTRIBUTION;

High-purity control law of energy-efficient distillation process is found the solution module, and in order to according to current concentration of component data, pattern function and current time performance variable value are asked for the ideal change value of current control variables, find the solution the control law Algebraic Equation set suc as formula (5) to formula (12)

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},......,n---\left(5\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\\ -\frac{1}{a-\ln \{p_s/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right))/\mathrm{\α}\left]\right\}})\end{array}i=\mathrm{1,2},......,f-1---\left(6\right)$

V ₁(k)＝F(1-q(k)-Δq(k)T) (7)

L _n(k)＝F(q(k)+Δq(k)T) (8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V ₁(k)+L _f-1(k) (10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(k\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{{\mathrm{HX}}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1({X_1}^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_1}^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+{\mathrm{FZ}}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}$

$=K_3({X_n}^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_n}^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, P _r(k) for working as k sampling instant rectifying section pressure, F is a feed flow rates, Z _fBe feed component concentration, V ₁(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y ₁(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X ₁ ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X ₁(k), X _n(k) be the k liquid phase light component concentration value Δ q (k) at the bottom of the cat head tower constantly, Δ P _r(k), be respectively the current desirable change value that the energy-efficient rectifying column control variables of current time is feed heat situation and rectifying section pressure.

Described host computer also comprises human-computer interface module, in order to set sampling period T, control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower ₁ ^*, X _n ^*, and the curve of output of display controller and controlled variable are the recording curve of liquid phase light component concentration at the bottom of the cat head tower.

A kind of high-purity control method of energy-efficient distillation process, described control method may further comprise the steps:

1) determine sampling period T, and with the T value, relative volatility α, stripping section pressure P _s, Anthony constant a, b, c, be kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower ₁ ^*, X _n ^*

3) obtain k sampling instant rectifying section pressure P from intelligence instrument _rStripping section pressure P _s, and each column plate temperature T _i, calculate liquid phase light component concentration value, calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=\mathrm{1,2},......,f-1---\left(1\right)$

$X_i\left(k\right)=\frac{P_s\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=f,f+1,......,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and 1 is the cat head numbering, and f is the feedboard numbering, and n numbers X at the bottom of for tower _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and a, b, c are the Anthony constant;

4) the concentration of component data that calculate with component inference module 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) (4):

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}}i=\mathrm{1,2},......,f-1---\left(3\right)$

${\hat{X}}_i=X_{\min ,s}+\frac{X_{\max ,s}-X_{\min ,s}}{1+e^{-k_s(i-S_s)}}i=f,f+1,......,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, k _r, X _{Min, s}, X _{Max, s}, k _s, S _r, S _sBe fitting parameter;

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

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},......,n---\left(5\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\\ -\frac{1}{a-\ln \{p_s/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right))/\mathrm{\α}\left]\right\}})\end{array}i=\mathrm{1,2},......,f-1---\left(6\right)$

V ₁(k)＝F(1-q(k)-Δq(k)T) (7)

L _n(k)＝F(q(k)+Δq(k)T) (8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V ₁(k)+L _f-1(k) (10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(k\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{{\mathrm{HX}}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1({X_1}^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_1}^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+{\mathrm{FZ}}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}---\left(12\right)$

$=K_3({X_n}^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_n}^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, P _r(k) for working as k sampling instant rectifying section pressure, F is a feed flow rates, Z _fBe feed component concentration, V ₁(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y ₁(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X ₁ ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X ₁(k), X _n(k) be the k liquid phase light component concentration value Δ q (k) at the bottom of the cat head tower constantly, Δ P _r(k), be respectively the current desirable change value that the energy-efficient rectifying column control variables of current time is feed heat situation and rectifying section pressure;

6) with the energy-efficient rectifying column control variables of current time be the current desirable change value Δ q (k) of feed heat situation and rectifying section pressure, Δ Pr (k) flows to the control station in the DCS system, adjusts the feed heat situation value and the rectifying section pressure values of energy-efficient rectifying column.

Described historical data base is a storage device in the DCS system, and control station reads historical data base, shows energy-efficient rectifying column course of work state.

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

Description of drawings

Fig. 1 is the structure chart of the high-purity control system of energy-efficient distillation process proposed by the invention.

Fig. 2 is the functional module structure figure of supervisory controller implementation method.

The specific embodiment

Specify the present invention below with reference to the accompanying drawings.

Embodiment 1

With reference to Fig. 1, Fig. 2, a kind of high-purity control system of energy-efficient distillation process, comprise and energy-efficient rectifying column 1 direct-connected field intelligent instrument 2 and DCS system, described DCS system comprises storage device 4, control station 5 and host computer 6, and wherein field intelligent instrument 2 is connected with data-interface 3, described data-interface 3 is connected with fieldbus, and described fieldbus is connected with storage device 4, control station 5 and host computer 6; Described host computer 6 comprises in order to calculate high-purity controller of the energy-efficient rectifying column control variables value of output, described high-purity controller comprises component inference module 9, model parameter adaptively correcting fitting module 10, high-purity control law of energy-efficient distillation process is found the solution module 11;

Component inference module 9 obtains temperature in order to host computer from intelligence instrument 2, and pressure data is calculated the concentration of component of each piece column plate of energy-efficient rectifying column, and concentration of component result of calculation is stored in the middle of the historical data base, and calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=\mathrm{1,2},......,f-1---\left(1\right)$

$X_i\left(k\right)=\frac{P_s\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=f,f+1,......,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and 1 is the cat head numbering, and f is the feedboard numbering, and n numbers X at the bottom of for tower _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and a, b, c are the Anthony constant.

Described model parameter adaptively correcting fitting module 10 adopts the concentration of component data that the component inference module calculates in the historical data bases, and online fitting pattern function, and fitting parameter stored in the middle of the historical data base, fitting function are suc as formula (3) (4):

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}}i=\mathrm{1,2},......,f-1---\left(3\right)$

${\hat{X}}_i=X_{\min ,s}+\frac{X_{\max ,s}-X_{\min ,s}}{1+e^{-k_s(i-S_s)}}i=f,f+1,......,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, k _r, X _{Min, s}, X _{Max, s}, k _sBe fitting parameter, S _r, S _sBe respectively the position of energy-efficient rectifying column rectifying section, stripping section liquid phase component CONCENTRATION DISTRIBUTION.

High-purity control law of described energy-efficient distillation process is found the solution module 11 according to current concentration of component data, pattern function and current time performance variable value are asked for the ideal change value of current control variables, find the solution the control law Algebraic Equation set suc as formula (5) to formula (12)

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},......,n---\left(5\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\\ -\frac{1}{a-\ln \{p_s/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right))/\mathrm{\α}\left]\right\}})\end{array}i=\mathrm{1,2},......,f-1---\left(6\right)$

V ₁(k)＝F(1-q(k)-Δq(k)T) (7)

L _n(k)＝F(q(k)+Δq(k)T) (8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V ₁(k)+L _f-1(k) (10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(k\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{{\mathrm{HX}}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1({X_1}^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_1}^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+{\mathrm{FZ}}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}---\left(12\right)$

$=K_3({X_n}^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_n}^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, P _r(k) for working as k sampling instant rectifying section pressure, F is a feed flow rates, Z _fBe feed component concentration, V ₁(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y ₁(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X ₁ ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X ₁(k), X _n(k) be the k liquid phase light component concentration value Δ q (k) at the bottom of the cat head tower constantly, Δ P _r(k), be respectively the current desirable change value of the energy-efficient rectifying column control variables of current time and feed heat situation and rectifying section pressure.

Described host computer 6 also comprises human-computer interface module 12, is used to set sampling period T, the control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower ₁ ^*, X _n ^*, and the curve of output of display controller and controlled variable are the recording curve of liquid phase light component concentration at the bottom of the cat head tower.

Embodiment 2

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

1) determine sampling period T, and with the T value, relative volatility α, stripping section pressure P _s, Anthony constant a, b, c, be kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower ₁ ^*, X _n ^*

3) obtain k sampling instant rectifying section pressure P from intelligence instrument _rStripping section pressure P _s, and each column plate temperature T _i, calculate liquid phase light component concentration value, calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=\mathrm{1,2},......,f-1---\left(1\right)$

$X_i\left(k\right)=\frac{P_s\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1}i=f,f+1,......,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and 1 is the cat head numbering, and f is the feedboard numbering, and n numbers X at the bottom of for tower _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and a, b, c are the Anthony constant.

4) the concentration of component data that calculate with component inference module 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) (4):

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}}i=\mathrm{1,2},......,f-1---\left(3\right)$

${\hat{X}}_i=X_{\min ,s}+\frac{X_{\max ,s}-X_{\min ,s}}{1+e^{-k_s(i-S_s)}}i=f,f+1,......,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, k _r, X _{Min, s}, X _{Max, s}, k _s, S _r, S _sBe fitting parameter.

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

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},......,n---\left(5\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\\ -\frac{1}{a-\ln \{p_s/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right))/\mathrm{\α}\left]\right\}})\end{array}i=\mathrm{1,2},......,f-1---\left(6\right)$

V ₁(k)＝F(1-q(k)-Δq(k)T) (7)

L _n(k)＝F(q(k)+Δq(k)T) (8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V ₁(k)+L _f-1(k) (10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(k\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{{\mathrm{HX}}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1({X_1}^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_1}^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+{\mathrm{FZ}}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}---\left(12\right)$

$=K_3({X_n}^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}({X_n}^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, P _r(k) for working as k sampling instant rectifying section pressure, F is a feed flow rates, Z _fBe feed component concentration, V ₁(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y ₁(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X ₁ ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X _l(k), X _n(k) be the k liquid phase light component concentration value Δ q (k) at the bottom of the cat head tower constantly, Δ P _r(k), be respectively the current desirable change value that the energy-efficient rectifying column control variables of current time is feed heat situation and rectifying section pressure;

6) with the energy-efficient rectifying column control variables of current time be the current desirable change value Δ q (k) of feed heat situation and rectifying section pressure, Δ Pr (k) flows to the control station in the DCS system, adjusts the feed heat situation value and the rectifying section pressure values of energy-efficient rectifying column.

Described historical data base is a storage device 4 in the DCS system, described DCS system comprises data-interface 3, storage device 4 and control station 5, wherein field intelligent instrument 2 is connected with data-interface 3, described data-interface 3 is connected with fieldbus, described fieldbus is connected with storage device 4, control station 5 and host computer 6, wherein control station can read historical data base, shows energy-efficient rectifying column course of work state.

Claims (4)

1. the high-purity control system of an energy-efficient distillation process, comprise and direct-connected field intelligent instrument of energy-efficient rectifying column and DCS system, described DCS system comprises storage device, control station and host computer, field intelligent instrument is connected with storage device, control station and host computer, described host computer comprises that described high-purity controller comprises in order to calculate high-purity controller of the energy-efficient rectifying column control variables value of output:

The component inference module, in order to obtaining temperature from intelligence instrument, pressure data is calculated the concentration of component of each piece column plate of energy-efficient rectifying column, and concentration of component result of calculation is stored in the middle of the historical data base, and calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1},i=1,2,\·\·\·\·\·\·,f-1---\left(2\right)$

$X_i\left(k\right)=\frac{P_s\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1},i=f,f+1,\·\·\·\·\·\·,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and l is the cat head numbering, and f is the feedboard numbering, n for tower at the bottom of numbering, X _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and a, b, c are the Anthony constant.

Model parameter adaptively correcting fitting module, in order to adopting the concentration of component data that the component inference module 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) (4):

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}},i=\mathrm{1,2},\·\·\·\·\·\·,f-1---\left(3\right)$

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}},i=f,f+1,\·\·\·\·\·\·,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, k _r, X _{Min, s}, X _{Max, s}, k _sBe fitting parameter, S _r, S _sBe respectively the position of energy-efficient rectifying column rectifying section, stripping section liquid phase component CONCENTRATION DISTRIBUTION;

High-purity control law of energy-efficient distillation process is found the solution module, and in order to according to current concentration of component data, pattern function and current time performance variable value are asked for the ideal change value of current control variables, find the solution the control law Algebraic Equation set suc as formula (5) to formula (12)

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},\·\·\·\·\·\·,n---\left(8\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b\left(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\right)\\ -\frac{1}{a-\ln \{\mathrm{Ps}/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right)/\mathrm{\α})}\end{array},i=\mathrm{1,2},\·\·\·\·\·\·,f-1---\left(6\right)$

V _l(k)＝F(1-q(k)-Δq(k)T)(7)

L _n(k)＝F(q(k)+Δq(k)T)(8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V _l(k)+L _f-1(k)(10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(t\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{H{X}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1(X_1^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}(X_1^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+F{Z}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}---\left(12\right)$

$=K_3(X_n^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}(X_n^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, P _r(k) for working as k sampling instant rectifying section pressure, F is a feed flow rates, Z _fBe feed component concentration, V _l(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y _l(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X _l ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X _l(k), X _n(k) the liquid phase light component concentration value Δ q (k) at the bottom of the k moment cat head tower, Δ P _r(k), be respectively the current desirable change value that the energy-efficient rectifying column control variables of current time is feed heat situation and rectifying section pressure.

2. the high-purity control system of energy-efficient distillation process as claimed in claim 1, it is characterized in that: described host computer also comprises human-computer interface module, in order to set sampling period T, control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower _l ^*, X _n ^*, and the curve of output of display controller and controlled variable are the recording curve of liquid phase light component concentration at the bottom of the cat head tower.

3. high-purity control method that realizes with the high-purity control system of energy-efficient distillation process as claimed in claim 1, it is characterized in that: described control method may further comprise the steps:

1) determine sampling period T, and with the T value, relative volatility α, stripping section pressure P _s, Anthony constant a, b, c, be kept in the middle of the historical data base;

2) set the control law parameter K ₁, K ₂, K ₃, K ₄With liquid phase light component concentration set point X at the bottom of the cat head tower _l ^*, X _n ^*

3) obtain k sampling instant rectifying section pressure P from intelligence instrument _rStripping section pressure P _s, and each column plate temperature T _i, calculate liquid phase light component concentration value, calculating formula is (1) (2):

$X_i\left(k\right)=\frac{P_r\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1},i=1,2,\·\·\·\·\·\·,f-1---\left(2\right)$

$X_i\left(k\right)=\frac{P_s\left(k\right)\×\mathrm{\α}\×{10}^{\frac{T_i\left(k\right)+c}{b}-a}-1}{\mathrm{\α}-1},i=f,f+1,\·\·\·\·\·\·,n---\left(2\right)$

Wherein k is current sampling instant, and following footnote i is a column plate numbering, and l is the cat head numbering, and f is the feedboard numbering, n for tower at the bottom of numbering, X _i(k) be k sampling instant liquid phase light component concentration, P _r(k) be k sampling instant rectifying section pressure, P _sStripping section pressure, T _i(k) be the temperature of each piece column plate in the k sampling instant tower, α is a relative volatility, and a, b, c are the Anthony constant;

4) the concentration of component data that calculate with component inference module 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) (4):

$\begin{array}{cc}{\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}}& i=\mathrm{1,2},\·\·\·\·\·\·,f-1---\left(3\right)\end{array}$

${\hat{X}}_i=X_{\min ,r}+\frac{X_{\max ,r}-X_{\min ,r}}{1+e^{-k_r(i-S_r)}},i=f,f+1,\·\·\·\·\·\·,n---\left(4\right)$

Wherein

Be that i piece column plate place liquid phase component concentration is estimated concentration, X _{Min, r}, X _{Max, r}, X _{Min, s}, X _{Max, s}, k _s, S _r, S _sBe fitting parameter;

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

$Y_i\left(t\right)=\frac{\mathrm{\α}{X}_i\left(t\right)}{(\mathrm{\α}-1)X_i\left(t\right)+1},i=\mathrm{1,2},\·\·\·\·\·\·,n---\left(8\right)$

$\begin{array}{c}{Q}_i\left(k\right)=\mathrm{UA}\×b\left(\frac{1}{a-\ln \{P_r\left(k\right)+\mathrm{\ΔPr}\left(k\right)T/[X_i\left(k\right)+(1-X_i\left(k\right))/\mathrm{\α}\left]\right\}}\right)\\ -\frac{1}{a-\ln \{\mathrm{Ps}/[X_{i+f-1}\left(k\right)+(1-X_{i+f-1}\left(k\right)/\mathrm{\α})}\end{array},i=\mathrm{1,2},\·\·\·\·\·\·,f-1---\left(6\right)$

V _l(k)＝F(1-q(k)-Δq(k)T)(7)

L _n(k)＝F(q(k)+Δq(k)T)(8)

$L_{f-1}\left(k\right)=\underset{i=1}{\overset{f-1}{\mathrm{\Σ}}}\frac{Q_i\left(k\right)}{\mathrm{\λ}}---\left(9\right)$

V _f(k)＝V _l(k)+L _f-1(k)(10)

$\frac{V_f\left(k\right)Y_f\left(k\right)-L_{f-1}\left(t\right)X_{f-1}\left(k\right)-V_1\left(k\right)Y_1\left(k\right)}{H{X}_{f-1}\left(k\right)}---\left(11\right)$

$=K_1(X_1^{*}-X_1\left(k\right))+K_2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}(X_1^{*}-X_1\left(i\right))T$

$\frac{-V_f\left(k\right)Y_f\left(k\right)-L_n\left(k\right)X_n\left(k\right)+L_{f-1}\left(k\right)X_{f-1}\left(k\right)+F{Z}_f}{H(X_{f-1}\left(k\right)-X_n\left(k\right))}---\left(12\right)$

$=K_3(X_n^{*}-X_n\left(k\right))+K_4\underset{i=1}{\overset{k}{\mathrm{\Σ}}}(X_n^{*}-X_n\left(i\right))T$

Wherein k is current sampling instant, and T is the sampling period, X _i(k), Y _i(k) be respectively k sampling instant i piece column plate light component liquid phase light component concentration and vapour phase light component concentration, Q _i(k) be thermal coupling amount between the i piece column plate, UA is a rate of heat transfer, X _I+f-1(k) be k sampling instant i+f-1 piece column plate liquid phase light component concentration, q (k) is a k sampling instant feed heat situation, and Pr (k) is for working as k sampling instant rectifying section pressure, and F is a feed flow rates, Z _fBe feed component concentration, V _l(k), V _f(k) be respectively the vapour phase flow rate at k sampling instant cat head and feedboard place, L _F-1(k), L _n(k) be respectively liquid phase flow rate at the bottom of k sampling instant f-1 piece column plate and the tower, H is a liquid holdup, X _F-1(k), X _n(k) be respectively liquid phase light component concentration at the bottom of k sampling instant f-1 piece column plate and the tower, Y _l(k), Y _f(k) be respectively the vapour phase light component concentration at k sampling instant cat head and feedboard place, K1, K2, K3, K4 are the control law parameter, X _l ^*, X _n ^*Be respectively liquid phase light component concentration set point at the bottom of the cat head tower, X _l(k), X _n(k) be the k liquid phase light component concentration value Δ q (k) at the bottom of the cat head tower constantly, Δ P _r(k), be respectively the current desirable change value that the energy-efficient rectifying column control variables of current time is feed heat situation and rectifying section pressure;

6) with the energy-efficient rectifying column control variables of current time be the current desirable change value Δ q (k) of feed heat situation and rectifying section pressure, Δ Pr (k) flows to the control station in the DCS system, adjusts the feed heat situation value and the rectifying section pressure values of energy-efficient rectifying column.

4. high-purity control method as claimed in claim 3 is characterized in that: described historical data base is a storage device in the DCS system, and control station reads historical data base, shows energy-efficient rectifying column course of work state.

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