CN101708375B - System and method for optimizing production potentiality of internal thermally coupled rectification column - Google Patents

Abstract

The invention discloses a system for optimizing the production potentiality of an internal thermally coupled rectification column, which comprises an on-site intelligent instrument which is connected with the internal thermally coupled rectification column, a control station, a database and an upper computer, wherein the upper computer comprises an optimized computing module which is used for optimization computing. The method for optimizing the production potentiality of the internal thermally coupled rectification column comprises the following steps of: setting structural parameters and operating parameters of the column and appointing an initial value of a feed flow rate; assuming compositions of all column plate liquid phases; respectively computing equilibrium temperature, vapor phase composition, vapor-liquid phase enthalpy value of each column plate; judging whether a condition is established or not: if the condition is established, continuing computing, or else, updating the liquid phase composition of each column plate; judging whether the product purity meets constraints or not: if the product purity does not meet the constraints, then finishing the iteration and outputting a result, wherein the feed flow rate of the previous step is the maximum feed quantity, and if the product purity meets the constraints, adding an iteration step size delta and continuing the iteration. The invention also provides a method for optimizing the production potentiality of the internal thermally coupled rectification column. The invention can ensure maximum production capacity and reduced energy consumption of unit product of the internal thermally coupled distillation column on the premise of keeping the product purity to meet the production requirements.

Description

Production potentiality of internal thermally coupled rectification column optimization system and method

Technical field

The present invention relates to the Finestill energy-saving field, especially, relate to a kind of production potentiality of internal thermally coupled rectification column optimization system and method.

Background technology

A the highest power-saving technology of energy-conservation usefulness in the four big energy-saving rectifying technology that internal thermal coupled rectifying is up to now to be proposed has worldwide obtained huge attention.Internal thermally coupled distillation column has reduced the condenser of conventional rectification tower and the thermic load of reboiler, let heat pass to stripping section from rectifying section, so rectifying section need be operated in than under the high pressure and temperature of stripping section.In order to regulate operating pressure, a compressor and a choke valve are arranged between two parts.Because the pressure differential and the thermal coupling structure of rectifying section and stripping section, the heat of some passes to stripping section from rectifying section, thereby to rectifying section downward phegma is provided, and to stripping section vapor stream upwards is provided.The flow velocity of rectifying section upwards successively decreases and the flow velocity of stripping section successively decreases downwards.Through the inner couplings of heat, can remove conventional reboiler and condenser, lot of energy is utilized again, thereby has significantly reduced energy consumption.Result of study shows that internal thermally coupled distillation column is compared with operating cost and can also be saved more than 30% with the energy consumption under the conventional rectification tower minimum reflux ratio.

Process optimization is the key that production process is designed and developed, and has effect very significantly for improving the process economy benefit.It is meant procedures system performance, characteristics under the given constraints, the device parameter and the operating condition that find the efficiency index that makes system or object function to reach minimum (maximum).The optimization of internal thermally coupled distillation column tower productive potentialities is meant keeping product purity to satisfy under the prerequisite of production requirement, finds the operating condition that makes that rectifying column output is maximum, reduces energy consumption of unit product, thereby reaches energy saving purposes.

Summary of the invention

Still do not have productive potentialities optimization system, the higher deficiency of energy consumption of unit product in order to overcome present internal thermal coupled distillation process, the present invention provides a kind of and can keep product purity to satisfy making under the prerequisite of production requirement that internal thermally coupled distillation column production capacity is maximum, reduce the production potentiality of internal thermally coupled rectification column optimization system and the method for energy consumption of unit product.

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

A kind of production potentiality of internal thermally coupled rectification column optimization system; Comprise the field intelligent instrument, control station, database and the host computer that are connected with internal thermally coupled distillation column; Said field intelligent instrument is connected with control station, database and host computer, and described host computer comprises:

Optimizing calculation module, in order to computation optimization, adopt following process to accomplish:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of vapour-liquid phase respectively to each column plate;

5) calculate the vapour-liquid phase flow rate of each column plate by formula (1) (2):

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}+F_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)

Wherein, UA representes heat couple coefficient, the Δ T temperature difference between column plate of representing to be coupled;

6) judge whether following formula (4) is set up,, then continue 7 if set up), otherwise the updating all column plates liquid phase is formed, and returns 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j{z}_{i,j}-(V_j+S_j^G)y_{\mathrm{ij}}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns 2) continue iteration.

As preferred a kind of scheme: said host computer also comprises: bubble point method module, and in order to calculate its equilibrium temperature by the bubble point method and vapour phase is formed, its process is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume v, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the rerum natura module;

3.3) check $|1-\underset{i}{\mathrm{\&Sigma;}}{y}_i|<0.0001$ Whether set up, set up then finishing iteration, return result of calculation, otherwise, upgrade the column plate equilibrium temperature, return 3.2) the continuation iteration.

As preferred another kind of scheme: said host computer also comprises: the enthalpy module, and in order to calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{{\mathrm{da}}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{{\mathrm{da}}^L}{\mathrm{dT}})/b^L---\left(12\right)$

H wherein _i ^*The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

As preferred another scheme: said host computer also comprises: the rerum natura module, and in order to calculate physical parameter, its process is following:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-3B^G-5B^{G^2}---\left(25\right)$

${\mathrm{\&gamma;}}^G=2(B^{G^3}+B^{G^2})-A^G{B}^G---\left(26\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝a ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-3B^L-5B^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^3}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

Further, described host computer also comprises: display module as a result is used for that The optimization results is passed to control station and shows, and through fieldbus The optimization results is delivered to operator station and shows;

The productive potentialities optimization method that the described production potentiality of internal thermally coupled rectification column optimization system of a kind of usefulness realizes, described productive potentialities optimization method may further comprise the steps:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of its vapour-liquid phase to each column plate;

5) simultaneous formula (1) (2) is calculated the vapour-liquid phase flow rate of each column plate:

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}+F_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)；

6) judge whether formula (4) is set up,, then continue step 7) if set up, otherwise, upgrade liquid phase and form, return the step 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j^G+z_{i,j}^G+F_j^L{z}_{i,j}^L-(V_j+S_j^G)y_{i,j}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns step 2) continue iteration.

As preferred a kind of scheme: in the said step 3), the process of being made up of bubble point method calculated equilibrium temperature and vapour phase is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume v, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the physical parameter computational methods;

3.3) check $|1-\underset{i}{\mathrm{\&Sigma;}}{y}_i|<0.0001$ Whether set up, set up then finishing iteration, return result of calculation, otherwise, upgrade the column plate equilibrium temperature, return step 3.2) the continuation iteration.

As preferred another kind of scheme: in the said step 4), calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{{\mathrm{da}}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{{\mathrm{da}}^L}{\mathrm{dT}})/b^L---\left(12\right)$

H wherein _i ^*The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

As preferred another scheme: said physical parameter computational methods may further comprise the steps:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-3B^G-5B^{G^2}---\left(25\right)$

${\mathrm{\&gamma;}}^G=2(B^{G^3}+B^{G^2})-A^G{B}^G---\left(26\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝a ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-3B^L-5B^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^3}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

Further, in described step 7), host computer is passed to control station with The optimization results and is shown, and through fieldbus The optimization results is delivered to operator station and shows.

Beneficial effect of the present invention mainly shows: 1, internal thermally coupled distillation column is carried out the productive potentialities computation optimization, instruct and produce; 2, excavate the device productive potentialities, under the prerequisite that keeps product purity to meet the demands, improve output; 3, reduce energy consumption of unit product, thereby improve productivity effect.

Description of drawings

Fig. 1 is the hardware structure diagram of productive potentialities optimization system proposed by the invention.

Fig. 2 is an internal thermally coupled distillation column structural representation according to the invention.

Fig. 3 is the functional structure chart of host computer of the present invention.

The specific embodiment

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

Embodiment 1

With reference to Fig. 1, Fig. 2, Fig. 3; A kind of energy-saving potentiality of internal thermally coupled rectification column optimization system; Comprise the field intelligent instrument 2, control station 4, database 5 and the host computer 6 that are connected with internal thermally coupled distillation column 1; Said field intelligent instrument 2 is connected with data-interface 3, and said data-interface 3 is connected with control station 4, database 5 and host computer 6, and described host computer 6 comprises:

Optimizing calculation module 7, in order to computation optimization, adopt following process to accomplish:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of vapour-liquid phase respectively to each column plate;

5) calculate the vapour-liquid phase flow rate of each column plate by formula (1) (2):

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}+F_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)

Wherein, UA representes heat couple coefficient, the Δ T temperature difference between column plate of representing to be coupled;

6) judge whether following formula (4) is set up,, then continue 7 if set up), otherwise the updating all column plates liquid phase is formed, and returns 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j{z}_{i,j}-(V_j+S_j^G)y_{\mathrm{ij}}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns 2) continue iteration.

Said host computer also comprises: bubble point method module 8, and in order to be made up of bubble point method its equilibrium temperature of calculating and vapour phase, its process is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume y, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the rerum natura module;

3.3) check $|1-\underset{i}{\mathrm{\&Sigma;}}{y}_i|<0.0001$ Whether set up, set up then finishing iteration, return result of calculation, otherwise, upgrade the column plate equilibrium temperature, return 3.2) the continuation iteration.

Said host computer 6 also comprises: enthalpy module 9, and in order to calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{{\mathrm{da}}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{{\mathrm{da}}^L}{\mathrm{dT}})/b^L---\left(12\right)$

H wherein _i ^*The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

Said host computer 6 also comprises: rerum natura module 10, and in order to calculate physical parameter, its process is following:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-3B^G-5B^{G^2}---\left(25\right)$

${\mathrm{\&beta;}}^G=A^G-3B^G-5B^{G^2}---\left(25\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝a ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-3B^L-5B^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^3}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

Described host computer 6 also comprises: display module 11 as a result, are used for that The optimization results is passed to control station and show, and through fieldbus The optimization results is delivered to operator station and shows.

The hardware structure diagram of the energy-saving potentiality of internal thermally coupled rectification column optimization system of present embodiment is shown in accompanying drawing 1; Described optimization system core by comprise optimizing calculation module 7, bubble point method module 8, enthalpy module 9, rerum natura module 10, the host computer 6 of display module 11 and man-machine interface constitutes as a result; Comprise in addition: field intelligent instrument 2, data-interface 3, control station 4, database 5 and fieldbus.Internal thermally coupled distillation column 1, intelligence instrument 2, data-interface 3, control station 4, database 5, host computer 6 link to each other through fieldbus successively, realize uploading and assigning of information flow.Optimization system is moved on host computer 6, can carry out information exchange with first floor system easily.

The functional structure chart of the optimization system of present embodiment mainly comprises optimizing calculation module 7, bubble point method module 8, enthalpy module 9, rerum natura module 10, display module 11 etc. as a result shown in accompanying drawing 3.

Described productive potentialities optimization method is implemented according to following steps:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of its vapour-liquid phase to each column plate;

5) simultaneous formula (1) (2) is calculated the vapour-liquid phase flow rate of each column plate:

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}+F_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)；

6) judge whether formula (4) is set up,, then continue step 7) if set up, otherwise, upgrade liquid phase and form, return the step 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j{z}_{i,j}-(V_j+S_j^G)y_{\mathrm{ij}}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns step 2) continue iteration.

Embodiment 2

With reference to Fig. 1, Fig. 2, Fig. 3, a kind of production potentiality of internal thermally coupled rectification column optimization method, described productive potentialities optimization method may further comprise the steps:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of its vapour-liquid phase to each column plate;

5) simultaneous formula (1) (2) is calculated the vapour-liquid phase flow rate of each column plate:

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}+F_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)；

6) judge whether formula (4) is set up,, then continue step 7) if set up, otherwise, upgrade liquid phase and form, return the step 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j{z}_{i,j}-(V_j+S_j^G)y_{\mathrm{ij}}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns step 2) continue iteration.

In the said step 3), the process of being made up of bubble point method calculated equilibrium temperature and vapour phase is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume v, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the physical parameter computational methods;

3.3) check $|1-\underset{i}{\mathrm{\&Sigma;}}{y}_i|<0.0001$ Whether set up, set up then finishing iteration, return result of calculation, otherwise, upgrade the column plate equilibrium temperature, return step 3.2) the continuation iteration.

In the said step 4), calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{{\mathrm{da}}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{{\mathrm{da}}^L}{\mathrm{dT}})/b^L---\left(12\right)$

H wherein _i ^*The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

Said physical parameter computational methods may further comprise the steps:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-3B^G-5B^{G^2}---\left(25\right)$

${\mathrm{\&gamma;}}^G=2(B^{G^3}+B^{G^2})-A^G{B}^G---\left(26\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝a ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-3B^L-5B^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^3}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

In described step 7), host computer is passed to control station with The optimization results and is shown, and through fieldbus The optimization results is delivered to operator station and shows.

Production potentiality of internal thermally coupled rectification column optimization system and method proposed by the invention; Be described through above-mentioned practical implementation step; Person skilled obviously can be in not breaking away from content of the present invention, spirit and scope to device as herein described with method of operating is changed or suitably change and combination, realize the present invention's technology.Special needs to be pointed out is, the replacement that all are similar and change apparent to one skilled in the artly, they all can be regarded as and be included in spirit of the present invention, scope and the content.

Claims (10)

1. production potentiality of internal thermally coupled rectification column optimization system; Comprise the field intelligent instrument, control station, database and the host computer that are connected with internal thermally coupled distillation column; Said field intelligent instrument is connected with control station, database and host computer, it is characterized in that: described host computer comprises:

Optimizing calculation module, in order to computation optimization, adopt following process to accomplish:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of vapour-liquid phase respectively to each column plate;

5) calculate the vapour-liquid phase flow rate of each column plate by formula (1) (2):

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}{+F}_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)

Wherein, UA representes heat couple coefficient, the Δ T temperature difference between column plate of representing to be coupled;

6) judge whether following formula (4) is set up,, then continue 7 if set up), otherwise the updating all column plates liquid phase is formed, and returns 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j{z}_{i,j}-(V_j+S_j^G)y_{i,j}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns 2) continue iteration.

2. production potentiality of internal thermally coupled rectification column optimization system as claimed in claim 1 is characterized in that: said host computer also comprises: bubble point method module, and in order to be made up of bubble point method its equilibrium temperature of calculating and vapour phase, its process is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume v, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the rerum natura module;

3.3) check

whether set up; Set up then finishing iteration; Return result of calculation; Otherwise, upgrade the column plate equilibrium temperature, return 3.2) the continuation iteration.

3. production potentiality of internal thermally coupled rectification column optimization system as claimed in claim 2 is characterized in that: said host computer also comprises: the enthalpy module, and in order to calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{d{a}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{d{a}^L}{\mathrm{dT}})/b^L---\left(12\right)$

Wherein

The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

4. production potentiality of internal thermally coupled rectification column optimization system as claimed in claim 2 is characterized in that: said host computer also comprises: the rerum natura module, and in order to calculate physical parameter, its process is following:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-{3B}^G-{5B}^{G^2}---\left(25\right)$

${\mathrm{\&gamma;}}^G=2(B^{G^3}+B^{G^2})-A^G{B}^G---\left(26\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝a ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-{3B}^L-{5B}^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^2}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

5. according to claim 1 or claim 2 production potentiality of internal thermally coupled rectification column optimization system, it is characterized in that: described host computer also comprises:

Display module is used for that The optimization results is passed to control station and shows as a result, and through fieldbus The optimization results is delivered to operator station and shows;

6. productive potentialities optimization method of realizing with production potentiality of internal thermally coupled rectification column optimization system as claimed in claim 1, it is characterized in that: described productive potentialities optimization method may further comprise the steps:

1) structural parameters and the operating parameter of setting tower are specified the feed rate initial value;

2) suppose each column plate liquid phase composition;

3), form by bubble point method its equilibrium temperature of calculating and vapour phase respectively to each column plate;

4), calculate the enthalpy of its vapour-liquid phase to each column plate;

5) simultaneous formula (1) (2) is calculated the vapour-liquid phase flow rate of each column plate:

$V_{j+1}{H}_{j+1}^G+U_{j-1}{H}_{j-1}^L+F_j{H}_j^F-(V_j+S_j^G)H_j^G-(U_j+S_j^L)H_j^L-Q_j=0---\left(1\right)$

$V_{j+1}+U_{j-1}{+F}_j^G+F_j^L-(V_j+S_j^G)-(U_j+S_j^L)=0---\left(2\right)$

Wherein, V representes the vapour phase flow, and U representes the liquid phase flow, and F representes feed rate, H ^FExpression charging enthalpy, S represent that side carries flow, H ^GAnd H ^LBe respectively vapour-liquid phase enthalpy, subscript j-1, j, j+1 represent j-1, j, j+1 piece plate respectively, and subscript L representes liquid phase, and subscript G representes vapour phase, and Q representes the thermal coupling amount, by computes:

Q＝UAΔT (3)；

6) judge whether formula (4) is set up,, then continue step 7) if set up, otherwise, upgrade liquid phase and form, return the step 3) iteration;

$V_{j+1}{y}_{i,j+1}+U_{j-1}{x}_{i,j-1}+F_j^G{z}_{i,j}^G+F_j^L{z}_{i,j}^L-(V_j+S_j^G)y_{i,j}-(U_j+S_j^L)x_{i,j}<0.0001---\left(4\right)$

Wherein, x is that liquid phase is formed, and y is that vapour phase is formed, and z is a feed composition, subscript i=1 ..., M representes component, M representes number of components;

7) judge that whether product purity satisfies constraint, if do not satisfy then finishing iteration, the output result, the feed rate of back is the maximum feed amount, if satisfy then feed rate is increased an iteration step length Δ, returns step 2) continue iteration.

7. productive potentialities optimization method as claimed in claim 6 is characterized in that: in the said step 3), the process of being made up of bubble point method calculated equilibrium temperature and vapour phase is following:

3.1) supposition column plate equilibrium temperature;

3.2) calculate the VLE constant, adopt following process to accomplish:

$\ln {\mathrm{\&Phi;}}_i^L=\ln \frac{\mathrm{RT}}{P(v^L-b^L)}-\frac{b_i}{b^L}(1-Z^L)+{\mathrm{\&xi;}}^L{a}^L(\frac{b_i}{b^L}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^L})/b^L\mathrm{RT}---\left(5\right)$

$\ln {\mathrm{\&Phi;}}_i^G=\ln \frac{\mathrm{RT}}{P(v^G-b^G)}-\frac{b_i}{b^G}(1-Z^G)+{\mathrm{\&xi;}}^G{a}^G(\frac{b_i}{b^G}-\frac{2\underset{m}{\mathrm{\&Sigma;}}{x}_m{a}_{i,m}}{a^G})/b^G\mathrm{RT}---\left(6\right)$

$K_i={\mathrm{\&Phi;}}_i^L/{\mathrm{\&Phi;}}_i^G---\left(7\right)$

y _i＝K _ix _i (8)

Wherein, Φ representes fugacity coefficient, and subscript L representes liquid phase, and subscript G representes vapour phase, and R is a gas constant, and T is a temperature, and P is a column plate pressure, subscript m=1 ..., M representes component, M representes number of components, molal volume v, physical parameter b ^G, b ^L, b _i, a ^G, a ^L, a _{I, m}, ξ ^G, ξ ^L, vapour phase compressibility factor Z ^G, liquid phase compressibility factor Z ^LCalculate by the physical parameter computational methods;

3.3) check

whether set up; Set up then finishing iteration; Return result of calculation; Otherwise, upgrade the column plate equilibrium temperature, return step 3.2) the continuation iteration.

8. productive potentialities optimization method as claimed in claim 7 is characterized in that: in the said step 4), calculate vapour-liquid phase enthalpy of mixing, its process is following:

$H_i^{*}=c_i+d_{i}T+e_i{T}^2+f_i{T}^3+h_i{T}^4---\left(9\right)$

$H^{*}=\underset{i}{\mathrm{\&Sigma;}}{y}_i{H}_i^{*}---\left(10\right)$

$H^G=H^{*}-\mathrm{RT}(1-Z^G)-{\mathrm{\&xi;}}^G(a^G-T\frac{d{a}^G}{\mathrm{dT}})/b^G---\left(11\right)$

$H^L=H^{*}-\mathrm{RT}(1-Z^L)-{\mathrm{\&xi;}}^L(a^L-T\frac{d{a}^L}{\mathrm{dT}})/b^L---\left(12\right)$

Wherein

The enthalpy of representing i pure component perfect gas, H ^*Be mixture perfect gas enthalpy, c, d, e, f, h are constant.

9. productive potentialities optimization method as claimed in claim 7 is characterized in that: said physical parameter computational methods may further comprise the steps:

$a_{i,m}={\mathrm{\&Omega;}}_{\mathrm{ai},m}{R}^2{T}_{\mathrm{ci},m}^2/P_{\mathrm{ci},m}---\left(13\right)$

b _i＝Ω _bRT _ci/P _cia (14)

$T_{\mathrm{ci},m}=\sqrt{T_{\mathrm{ci}}{T}_{\mathrm{cj}}}(1-k_{i,m})---\left(15\right)$

$V_{\mathrm{ci},m}=0.125{(V_{\mathrm{ci},m}^{1/3}+V_{\mathrm{ci},m}^{1/3})}^3---\left(16\right)$

Z _ci，m＝0.5(Z _ci+Z _cm) (17)

P _ci，m＝RT _ci，mZ _ci，m/V _ci，m (18)

Ω _ai，m＝0.5(Ω _ai+Ω _am) (19)

To vapour phase:

$a^G=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{y}_i{y}_m{a}_{i,m}---\left(20\right)$

$b^G=\underset{i}{\mathrm{\&Sigma;}}{y}_i{b}_i---\left(21\right)$

Order

A ^G＝a ^GP/R ²T ² (22)

B ^G＝b ^GP/RT (23)

α ^G＝2B ^G-1 (24)

${\mathrm{\&beta;}}^G=A^G-{3B}^G-{5B}^{G^2}---\left(25\right)$

${\mathrm{\&gamma;}}^G=2(B^{G^3}+B^{G^2})-A^G{B}^G---\left(26\right)$

Getting initial value is 1-0.6P _r, separate following equation with Newton method, promptly obtain vapour phase compressibility factor Z ^G

$Z^{G^3}+{\mathrm{\&alpha;}}^G{Z}^{G^2}+\mathrm{\&beta;}{Z}^G+{\mathrm{\&gamma;}}^G=0---\left(27\right)$

Then,

v ^G＝RT/PZ ^G (28)

${\mathrm{\&xi;}}^G=0.242536\ln \frac{v^G+3.561553b^G}{v^G-0.561553b^G}---\left(29\right)$

To liquid phase:

$a^L=\underset{i}{\mathrm{\&Sigma;}}\underset{m}{\mathrm{\&Sigma;}}{x}_i{x}_m{a}_{i,m}---\left(30\right)$

$b^L=\underset{i}{\mathrm{\&Sigma;}}{x}_i{b}_i---\left(31\right)$

Order

A ^L＝α ^LP/R ²T ² (32)

B ^L＝b ^LP/RT (33)

α ^L＝2B ^L-1 (34)

${\mathrm{\&beta;}}^L=A^L-{3B}^L-{5B}^{L^2}---\left(35\right)$

${\mathrm{\&gamma;}}^L=2(B^{L^3}+B^{L^2})-A^L{B}^L---\left(36\right)$

Getting initial value is P _r(0.106+0.078P _r), separate following equation with Newton method, promptly obtain liquid phase compressibility factor Z ^L

$Z^{L^3}+{\mathrm{\&alpha;}}^L{Z}^{L^2}+\mathrm{\&beta;}{Z}^L+{\mathrm{\&gamma;}}^L=0---\left(37\right)$

Then,

v ^L＝RT/PZ ^L (38)

${\mathrm{\&xi;}}^L=0.242536\ln \frac{v^L+3.561553b^L}{v^L-0.561553b^L}---\left(39\right)$

Ω _ai＝C _i-D _iτ+E _iτ ²-W _iτ ³ (40)

Ω _b＝0.070721 (41)

τ＝0.01T (42)

Wherein, A, B, α, β, γ, τ, Ω _a, Ω _bBe intermediate variable, C, D, E, W are constants, T _c, P _c, V _c, Z _cBe respectively critical-temperature, pressure, volume and compressibility factor, P _rBe reduced pressure, R is a gas constant, k _{I, m}The mutual coefficient of binary of representing i component and m component, k _{I, m}Be constant, subscript c representes the character of critical point, and subscript r representes reduced state, subscript i, and m representes the binary mixture of i component and m component.

10. like claim 6 or 7 described productive potentialities optimization methods; It is characterized in that: in described step 7); Host computer is passed to control station with The optimization results and is shown, and through fieldbus The optimization results is delivered to operator station and shows.

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