CN104656457A - Calculating method of internal pressure of loop reactor for propylene polymerization - Google Patents

Abstract

The invention relates to a calculating method of the internal pressure of a loop reactor for propylene polymerization. The calculating method is based on a dynamic mathematic model of a core loop reactor in an industrial polypropylene full-process technology and combines a dynamical model of propylene homopolymerization and a state equation for a high-pressure liquid to calculate the internal pressure of the loop reactor. According to the invention, the most important characteristic lies in that only through a laboratory scale in advance, a dynamical parameter data of the propylene polymerization is obtained, and the structural size and the operating technological condition of an industrial loop reactor are input without collecting the dynamical data of the industrial-scale propylene polymerization, so that the internal pressure of the loop reactor for the industrial propylene polymerization in a very wide scale of production can be calculated. The calculating method of the internal pressure of the loop reactor for propylene polymerization has the advantages of high convenience, high efficiency and low cost, the simulation efficiency of the loop reactor under an unsteady-state accident condition and the response frequency of the loop reactor to the main operating performance can be greatly improved, so that the potential safety hazard of the industrial loop reactor during the operation is reduced, and the production economic efficiency and the market competitiveness are improved.

Description

A kind of propylene polymerization annular-pipe reactor internal pressure computing method

Technical field

The present invention relates to a kind of industrial propylene polymerization annular-pipe reactor internal pressure computing method.

Background technology

Spheripol polymarization method for prodcing polyacrylates/device is one of main at present PP Production Technology, also referred to as liquid-phase bulk loop po lymerisation technique.Wherein, annular-pipe reactor is one of this technique core reaction device, is mainly used to produce HOPP product.Taking in above-mentioned explained hereafter polypropylene process, the pressure in annular-pipe reactor can affect polymerization rate, material turnover amount and product quality.In addition, because the propylene homo reaction in annular-pipe reactor is strong exothermal reaction, react acutely wayward, the fluctuation of input and output material flow, material composition and process units actual motion condition all can cause the sharply rising of temperature and pressure in annular-pipe reactor, reactor failure, causes serious security incident.Therefore, the data of the temperature, pressure and the dump amount that obtain in polypropylene liquid-phase annular-pipe reactor are necessary.From safety in production angle, especially need ring pipe reactor internal pressure.

Through finding the existing retrieval about industrial propylene polymerization annular-pipe reactor interior flow field computing method (pressure parameter belongs to one of Flow Field Distribution parameter) document, although there is large quantities of scientific worker to carry out the imitation and calculation work of industrial propylene polymerization annular-pipe reactor interior flow field parameter, but correlative study concentrates on the calculating of temperature, polypropylene solid holdup, polymerisation conversion, melt index and particle size distribution in annular-pipe reactor, seldom relates to the calculating of reactor internal pressure.In the recent period, (the Luo Z.H. such as Luo Z.H., Su P.L., WuW. " Industrial loop reactor for catalytic propylene polymerization:Dynamic modelingat emergency accidents ", Industrial & Engineering Chemistry Research.2010, 49:11232-11243) establish one and calculate propylene polymerization annular-pipe reactor internal pressure model, model is propylene polymerization kinetics equation, annular-pipe reactor dynamic mathematical models, the state equation of highly pressurised liquid and the import and export material mouth of pipe equation of annular-pipe reactor are coupled, and calculate internal pressure in conjunction with mouth of pipe equation by the pressure reduction at endless tube two ends, but need too many undetermined parameter owing to importing and exporting in material mouth of pipe equation, this calculation of pressure model is suitable for, and category is little (can only be used for calculating double loop reactor technique, can not be used for calculating single loop reactors technique, in addition, because many undetermined parameters are relevant to catalyst type in mouth of pipe equation, be difficult to the relation obtaining catalyst for polymerization of propylene type and these undetermined parameters at present, therefore catalyst for polymerization of propylene Change of types easily causes the model calculation to be dispersed, and calculating cannot successfully).

Summary of the invention

Not high and be suitable for the little deficiency of category in order to overcome existing propylene homo annular-pipe reactor calculation of pressure method computational accuracy, the invention provides and a kind ofly simple and effectively have be suitable for the wide propylene homo annular-pipe reactor calculation of pressure method of category with low cost.The present invention directly adopts the state equation of highly pressurised liquid to calculate reactor internal pressure.Wherein, the temperature in state equation and density parameter are calculated by the dynamic mathematical models of polymerized loop reactor, and in dynamic model, input parameter associates with the material performance at endless tube two ends.Therefore, the present invention is not having directly to calculate overpressure by means of only state equation under mouth of pipe equation yet, not only eliminates the undetermined parameter many (affecting by catalyst type by computation process) that mouth of pipe equation brings, has easy advantage.In addition, (the Luo Z.H. such as Luo Z.H., Su P.L., Wu W. " Industrial loop reactor for catalytic propylenepolymerization:Dynamic modeling at emergency accidents ", Industrial & Engineering Chemistry Research.2010, 49:11232-11243) owing to there is mouth of pipe equation in computing method, and this needs pipe two ends to there is obvious pressure reduction, this feature mainly exists at dicyclo Guan Zhongcai, therefore the computing method in document are only applicable to the dicyclo pipe that can there is obvious pressure reduction.The present invention is not owing to having mouth of pipe equation, and therefore the present invention is not only applicable to dicyclo pipe, is applicable to monocycle pipe yet, has wider adaptation category.

Main technical schemes of the present invention is: the rate of change first being obtained main material by the polymerization kinetics equation of endless tube inside, the dynamic response device mathematical model solving endless tube inside on this basis obtains the mass concentration of each material, density and temperature, and is directly obtained the pressure data of endless tube inside by the state equation of highly pressurised liquid.

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

A kind of industrial propylene polymerization annular-pipe reactor internal pressure computing method, described method comprises the steps:

1), propylene homo dynamics mathematical model structure is set up, see formula (1)-(6):

r _P=k _P[M][C*] (1)

-r _tr=k _tr[H ₂] ^0.5[C*] (2)

-r _d=k _d[C*] (3)

$k_p=k_{p0}\exp (-\frac{E_p}{8.314T})---\left(4\right)$

$k_{\mathrm{tr}}=k_{\mathrm{tr}0}\exp (-\frac{E_{\mathrm{tr}}}{8.314\mathrm{RT}})---\left(5\right)$

$k_d=k_{d0}\exp (-\frac{E_d}{8.314T})---\left(6\right)$

R in formula _p, r _trand r _drepresent that (unit is molm to polymerization rate of rise respectively ^-3s ^-1), (unit is molm to polymeric chain transfer rate ^-3s ^-1) and polymerization catalyst deactivation rate (unit is molm ^-3s ^-1), k _p, k _trand k _drepresent that (unit is m to polymerization rate constant of propagation respectively ³(mols) ^-1), (unit is m to polymeric chain transfer rate constant ^1.5mol ^-0.5s ^-1) and polymerization catalyst decay rate constants (s ^-1), k _p0, k _tr0and k _d0represent the constant (also claiming frequency factor) of each corresponding speed equation respectively, E _p, E _trand E _drepresent that (unit is Jmol to the corresponding energy of activation reacted of each rate equation respectively ^-1), [M] represents that (unit is molm to propylene monomer concentration ^-3), [C ^*] represent that (unit is molm to catalyst active center's concentration ^-3), [H ₂] represent that (unit is molm to density of hydrogen ^-3), T represents the temperature (unit is K) of polyreaction.Wherein k _p0, k _tr0and k _d0and E _p, E _trand E _ddirectly obtain after the propylene polymerization dynamics data that room lab scale obtains by experiment.Thus, under the concrete polymeric reaction temperature of input, get final product through type (1)-(6) calculate each polymerization rate (polymerization rate of rise, (unit is molm to polymeric chain transfer rate ^-3s ^-1) and polymerization catalyst deactivation rate).

2), to Spheripol loop polypropylene industrial flow (see accompanying drawing 1), the dynamic mathematical models structure of the bulk propylene polymerization annular-pipe reactor of its core composition is set up, see formula (7)-(12):

$V_i\frac{d{\left[M\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[M\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[M\right]}_i-r_{\mathrm{pi}}{V}_i---\left(7\right)$

$V_i\frac{d{\left[C^{*}\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[C^{*}\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[C^{*}\right]}_i-r_{\mathrm{di}}{V}_i---\left(8\right)$

$V_i\frac{d{\left[H_2\right]}_i}{\mathrm{dt}}=G_{H_2}_i^{\mathrm{in}}/M_{H_2}(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[H_2\right]}_i-r_{\mathrm{tri}}{V}_i---\left(9\right)$

$V_i{\mathrm{\ρ}}_i\frac{{\mathrm{dw}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{w}_i-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})w_i+r_{\mathrm{pi}}{V}_i{M}_p---\left(10\right)$

$\frac{{\mathrm{dm}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})---\left(11\right)$

$V_i{\mathrm{\ρ}}_i{C}_{\mathrm{pi}}\frac{{\mathrm{dT}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{G}_{\mathrm{pi}}^{\mathrm{in}}{T}_{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})C_{\mathrm{pi}}{T}_{\mathrm{out}}+(-{\mathrm{\ΔH}}_{\mathrm{ri}})r_{\mathrm{pi}}{V}_i-{\mathrm{KA}}_i(T_i-T_{\mathrm{ji}})---\left(12\right)$

In formula, A represents that (unit is m for the total heat conduction area of reactor ²), C _prepresent that (unit is Jkg to material thermal capacitance ^-1k ^-1), G represents that (unit is kgs to mass flow of materials ^-1), represent that (unit is kgs to hydrogen quality flow ^-1), K represents that (unit is wm for the overall heat transfer coefficient of reactor wall ²k ^-1), m represents quality of material in reactor (unit is kg), (unit is molm to the molal weight of expression hydrogen ^-3), M _prepresent that (unit is molm to polyacrylic molal weight ^-3), Q represents that (unit is m for the volumetric flow rate of material ³s ^-1), t represents that (unit is s) to polymerization time, and V represents volume (unit m ³), w represents the solid holdup in reactor, and ρ represents that (unit is kgm to material density in reactor ^-3), Δ H _rrepresent that (unit is kJmol to propylene polymerization enthalpy ^-1); Subscript i represents Spheripol loop polypropylene commercial plant i-th annular-pipe reactor; Subscript in, out and relife represent the charging of reactor respectively, discharging and releasing.Except [M], [C in reactor in formula ^*], [H ₂], w, m and T be outside unknown variable, other parameter/variable is physical dimension and the operating procedure condition data thereof of the industrial annular-pipe reactor of kinetic rate data or the input calculated by other model.

3), use the state equation of highly pressurised liquid to realize calculating to annular-pipe reactor internal pressure, the state equation of highly pressurised liquid is see formula (13)-(28):

First the density of the propylene monomer of i-th annular-pipe reactor inside is calculated according to formula (13):

${\mathrm{\ρ}}_{M,i}=\frac{m_i(1-w_i)}{V_i-m_i{w}_i/{\mathrm{\ρ}}_{\mathrm{PP}}}---\left(13\right)$

ρ in formula _m,i(unit is kgm to the density of expression i-th annular-pipe reactor inner propene ^-3).

Secondly, Tait equation is used to the pressure solving endless tube inside, sees formula (14):

$\frac{V_i}{{V_i}^0}=1-D\ln \frac{P_i+\mathrm{EE}}{P^0+\mathrm{EE}}---\left(14\right)$

Arrangement formula (14) obtains formula (15):

$P_{r,i}=\mathrm{Exp}\left[\frac{1}{D}(1-\frac{v_i}{v^0})\right]({P_r}^0+\mathrm{EE})-\mathrm{EE}---\left(15\right)$

In formula (15):

$P_{r,i}=\frac{P_i}{P_c}---\left(16\right)$

$v_i=\frac{1}{{\mathrm{\ρ}}_{M,i}}---\left(17\right)$

D=Exp(-2.5355+1.1690ξ+0.1458T _br) (18)

$\mathrm{EE}=(\frac{45.1906}{{T_r}^2}-\frac{45.8849}{T_r}-1)\mathrm{Exp}[2.6583\mathrm{\ξ}+3.7148\ln T_{\mathrm{br}})---\left(19\right)$

$v^0=\frac{{\mathrm{RT}}_c}{P_c}\mathrm{Exp}\{-(1.2310+0.8777\mathrm{\ξ})[1+{(1-T_r)}^{2/7}\left]\right\}---\left(20\right)$

${P_r}^0=\frac{P^0}{P_c}---\left(21\right)$

P in formula (21) ⁰represent the saturation pressure of high pressure propylene liquid, calculated by formula (22):

$P^0=\mathrm{Exp}(A-\frac{B}{T+C})---\left(22\right)$

In formula (22):

A=ln101325+(B/T _c)(T _br+C/T _c) (23)

B=T _c[(1+C/T _c)(T _br+C/T _c)ln(P _c/101325)]/(1-T _br) (24)

C=T _c(0.7F-0.3T _br)/(0.3-F) (25)

F=[(1-T _br)(1+β)ln10]/[ln(P _c/101325)] (26)

T _r=T/T _c(27)

T _br=T _b/T _c(28)

Formula (13)-(28) constitute the state equation of high-pressure liquid propylene.In addition, formula (13)-(28) are except [M] in reactor, [C ^*], [H ₂], outside w, m, T and P, other is and the thermodynamic parameter of propylene liguid relation or physical parameter (their numerical value is fixed, and value is see subordinate list 1).Therefore, [M], [C in the reactor calculated in the thermodynamic parameter of high-pressure liquid propylene, relevant physical data and above-mentioned reactor dynamic model structure is inputted ^*], [H ₂], w, m and T value, the pressure (P) of annular-pipe reactor inside can be obtained.

Application the inventive method, by changing the reactor scale parameter (as reactor volume, total heat conduction area and feed rate) inputted in the dynamic mathematical models structure of propylene polymerization annular-pipe reactor, just can calculate the pressure of the annular-pipe reactor inside of random scale, realize the calculating of industrial propylene polymerization annular-pipe reactor internal pressure.

Technical conceive of the present invention is: with any one annular-pipe reactor in the propylene polymerization device extensively adopted at present for object, set up the dynamic mathematical models structure of annular-pipe reactor, dynamics data required in this dynamic mathematical models structure is obtained by propylene polymerization kinetic model, temperature in the reactor using the state equation of high pressure propylene liquid that the pressure parameter of calculative inside reactor and dynamic mathematical models are solved to obtain and material content parameter associate, in conjunction with the physical dimension of industrial annular-pipe reactor and the dynamic mathematical models parameter of execute-in-place process conditions Data Update annular-pipe reactor thereof, then by the state equation calculating pressure of above-mentioned high pressure propylene liquid, realize the calculating to the production-scale annular-pipe reactor internal pressure of difference.

The present invention is applicable to all Loop Reactor for Polypropylene inner gauges and calculates, and tool is not by the restriction of catalyst type.In addition, scheme provided by the invention also can for the calculation of pressure under olefin-copolymerization system in endless tube.

The advantage of method for designing of the present invention is easy understand, easy to use, and have simple and effective and low cost, computational accuracy is high and applicable category is wide.The present invention and Luo Z.H. etc. (" Industrial loop reactor forcatalytic propylene polymerization:Dynamic modeling at emergency accidents ", Industrial & Engineering Chemistry Research.2010, the difference of computing method 49:11232-11243) is, this calculation of pressure method has been coupled the import and export material mouth of pipe equation of annular-pipe reactor, too many undetermined parameter is needed owing to importing and exporting in material mouth of pipe equation, make that this calculation of pressure model computational accuracy is not high and applicable category is little (can only be used for calculating double loop reactor technique, can not be used for calculating single loop reactors technique, in addition, catalyst for polymerization of propylene Change of types easily causes the model calculation to be dispersed, and calculating cannot successfully).The annular-pipe reactor that the present invention is single from polypropylene plant, other endless tube be connected with this endless tube or equipment are processed by material and energy balance equation, thus delete the above-mentioned mouth of pipe equation mentioned, greatly reduce the undetermined parameter in pressure model, make calculation of pressure method of the present invention can successfully calculate industrial propylene polymerization annular-pipe reactor internal pressure within the scope of quite wide production scale, there is simple and effective and advantage that is low cost.

This method application process can be roughly divided into 3 stages:

1, the setting of model structure parameter, needs the parameter of setting as follows:

1), input power model parameter k in configuration interface _p0, k _tr0and k _d0and E _p, E _trand E _d;

2), in configuration interface input reactor dynamic mathematical models in the physical dimension V of industrial annular-pipe reactor and A) and operating procedure condition data (G, Q, P and T);

3), the physical property of the material of input reactor and thermodynamic parameter (C in configuration interface _p, K, m _p, Δ H _r, ρ, β and ζ).

The setting of parameter can be completed by clicking "+" and "-" in interface.After parameter confirms, click the renewal rewards theory that " model modification " starts model parameter, will be preserved according in feeding dynamic data base by industrial computer simultaneously.

2, the calculating of pressure in annular-pipe reactor.The CPU starting industrial computer calls " the annular-pipe reactor inner gauge calculation method " that weave in advance, the model parameter of the above-mentioned input of this model read, calculate propylene polymerization kinetic rate, then adopt the temperature in reactor dynamic mathematical models calculating reactor and material content parameter, and then call the pressure in equation of state for high-pressure liquid calculating reactor.After pressure parameter calculates, be display calculation of pressure result at the upper ledge at configuration interface.

3, annular-pipe reactor inner gauge calculates interpretation of result and output.Click " calculation of pressure interpretation of result and the output " button at configuration interface, start interpretation of result and output, comprise maximum pressure data export and result of calculation I preserve and print, thus complete the calculating of a pressure.To carry out the calculating of another time, repeat whole implementation, then can complete another calculation of pressure.

A complete set of propylene polymerization annular-pipe reactor internal pressure computation process can complete on industrial computer configuration interface, the industrial exemplary application that this process hereinafter can provide with reference to this instructions.Hereafter specific implementation method illustrates actual effect of the present invention for polypropylene homopolymer common in polypropylene production process, but range of application of the present invention is not limited with the calculation of pressure in the present embodiment.As previously mentioned, the present invention, except may be used for polypropylene homopolymer production run, also can be used for the polypropylene copolymer production run adopting annular-pipe reactor.

Beneficial effect of the present invention is mainly manifested in: 1, simplicity of design, easy understand, be easy to implement, cost is low and practical; 2, category is suitable for wide, greatly can improve annular-pipe reactor in unstable state accident conditions Imitating efficiency and it is to the response frequency of main operating performance, thus reduce the potential safety hazard of industrial annular-pipe reactor in operational process, increase production economy benefit and the market competitiveness.

Accompanying drawing explanation

Fig. 1 is Spheripol PP Production Technology process flow diagram;

1-bulk copolymerization unit; 2-high-pressure degas; 3-low pressure is degassed; 4-gas evaporate to dryness is dry; 5-extruder grain; 6-packs; 7-MONOMER RECOVERY; 8-gas-phase copolymerization; 9-monomer pressure recovery.

Fig. 2 is computing method block diagram of the present invention;

Fig. 3 is the annular-pipe reactor figure calculated in embodiment;

Fig. 4 is the annular-pipe reactor internal pressure figure calculated in embodiment.

Embodiment

For ease of understanding the present invention further, the invention will be further elaborated for the following example.

The present embodiment is designed productive capacity is three annular-pipe reactors (R200, R201 and R202 in 300,000 tons/year of polyacrylic Spheripol loop polypropylene production technologies, see accompanying drawing 3) calculated examples of internal pressure when normal production, in such cases, reactor is without releasing.The top pressure finally calculating three reactors (R200, R201 and R202) inner is respectively 4.18,4.61 and 4.84Mpa, and the maximum pressure that designs with three reactors (be respectively 4.2,4.6 and 4.8Mpa) closely.Concrete computation process is as follows:

1, in the optimum configurations interface at configuration interface, the setting of prior input parameter value required in calculation of pressure model is completed by clicking "+" and "-", as follows:

1), input power model parameter k in configuration interface _p0, k _tr0and k _d0and E _p, E _trand E _d;

2), in configuration interface input reactor dynamic mathematical models in the physical dimension (V and A) of industrial annular-pipe reactor and operating procedure condition data (G, Q, P and T) thereof;

3), the physical property of the material of input reactor and thermodynamic parameter (C in configuration interface _p, K, m _p, Δ H _r, ρ, β and ζ).

The parameter value of above-mentioned needs input sees attached list 1.

2, on configuration interface, click " model modification " button and enter next configuration interface, the CPU starting industrial computer calls " annular-pipe reactor inner gauge the calculates model " software package woven in advance and carries out calculation of pressure.Concrete computation process is as follows:

1) according to the kinetic parameters of above-mentioned input, propylene polymerization kinetic rate r can be obtained by formula (1)-(6) _p, r _trand r _d

r _P=k _P[M][C*] (1)

-r _tr=k _tr[H ₂] ^0.5[C*] (2)

-r _d=k _d[C*] (3)

$k_p=k_{p0}\exp (-\frac{E_p}{8.314T})---\left(4\right)$

$k_{\mathrm{tr}}=k_{\mathrm{tr}0}\exp (-\frac{E_{\mathrm{tr}}}{8.314\mathrm{RT}})---\left(5\right)$

$k_d=k_{d0}\exp (-\frac{E_d}{8.314T})---\left(6\right)$

2) physical dimension of industrial annular-pipe reactor and operating procedure condition data thereof and above-mentionedly calculate propylene polymerization kinetic rate numerical value in the dynamic mathematical models according to the annular-pipe reactor of above-mentioned input, can obtain temperature (T) in reactor and material content parameter ([M], [C by formula (7)-(12) ^*], [H ₂, w and m)

$V_i\frac{d{\left[M\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[M\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[M\right]}_i-r_{\mathrm{pi}}{V}_i---\left(7\right)$

$V_i\frac{d{\left[C^{*}\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[C^{*}\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[C^{*}\right]}_i-r_{\mathrm{di}}{V}_i---\left(8\right)$

$V_i\frac{d{\left[H_2\right]}_i}{\mathrm{dt}}=G_{H_2}_i^{\mathrm{in}}/M_{H_2}(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[H_2\right]}_i-r_{\mathrm{tri}}{V}_i---\left(9\right)$

$V_i{\mathrm{\ρ}}_i\frac{{\mathrm{dw}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{w}_i-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})w_i+r_{\mathrm{pi}}{V}_i{M}_p---\left(10\right)$

$\frac{{\mathrm{dm}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})---\left(11\right)$

$V_i{\mathrm{\ρ}}_i{C}_{\mathrm{pi}}\frac{{\mathrm{dT}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{G}_{\mathrm{pi}}^{\mathrm{in}}{T}_{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})C_{\mathrm{pi}}{T}_{\mathrm{out}}+(-{\mathrm{\ΔH}}_{\mathrm{ri}})r_{\mathrm{pi}}{V}_i-{\mathrm{KA}}_i(T_i-T_{\mathrm{ji}})---\left(12\right)$

3) pressure value in reactor can be obtained by formula (13)-(28) according to the physical property of above-mentioned input and thermodynamic parameter data and above-mentioned temperature in reactor and the material content parameter of calculating

${\mathrm{\ρ}}_{M,i}=\frac{m_i(1-w_i)}{V_i-m_i{w}_i/{\mathrm{\ρ}}_{\mathrm{PP}}}---\left(13\right)$

$\frac{V_i}{{V_i}^0}=1-D\ln \frac{P_i+\mathrm{EE}}{P^0+\mathrm{EE}}---\left(14\right)$

$P_{r,i}=\mathrm{Exp}\left[\frac{1}{D}(1-\frac{v_i}{v^0})\right]({P_r}^0+\mathrm{EE})-\mathrm{EE}---\left(15\right)$

$P_{r,i}=\frac{P_i}{P_c}---\left(16\right)$

$v_i=\frac{1}{{\mathrm{\ρ}}_{M,i}}---\left(17\right)$

D=Exp(-2.5355+1.1690ξ+0.1458T _br) (18)

$\mathrm{EE}=(\frac{45.1906}{{T_r}^2}-\frac{45.8849}{T_r}-1)\mathrm{Exp}[2.6583\mathrm{\ξ}+3.7148\ln T_{\mathrm{br}})---\left(19\right)$

$v^0=\frac{{\mathrm{RT}}_c}{P_c}\mathrm{Exp}\{-(1.2310+0.8777\mathrm{\ξ})[1+{(1-T_r)}^{2/7}\left]\right\}---\left(20\right)$

${P_r}^0=\frac{P^0}{P_c}---\left(21\right)$

$P^0=\mathrm{Exp}(A-\frac{B}{T+C})---\left(22\right)$

A=ln101325+(B/T _c)(T _br+C/T _c) (23)

B=T _c[(1+C/T _c)(T _br+C/T _c)ln(P _c/101325)]/(1-T _br) (24)

C=T _c(0.7F-0.3T _br)/(0.3-F) (25)

F=[(1-T _br)(1+β)ln10]/[ln(P _c/101325)] (26)

T _r=T/T _c(27)

T _br=T _b/T _c(28)

3, on configuration interface, click " calculation of pressure interpretation of result and output " button and enter next configuration interface, export result of calculation.Three the annular-pipe reactor internal pressure data calculated are shown in accompanying drawing 4.

Table 1 (a)

Table 1 (b)

Table 1 (C)

Table 1 (d)

Note: due to normal production, without releasing, the G of all reactors ^relifewith Q ^relifeall get 0.

Claims (5)

1. propylene polymerization annular-pipe reactor internal pressure computing method, said method comprising the steps of:

1) rate of change that propylene homo dynamics mathematical model obtains main material is set up;

2) set up the dynamic mathematical models of bulk propylene polymerization annular-pipe reactor, obtain the mass concentration of each material, density and temperature;

3) temperature in the reactor using the state equation of high pressure propylene liquid the pressure parameter of inside reactor and dynamic mathematical models to be solved to obtain and material content parameter associate, and calculate the pressure of annular-pipe reactor inside.

2. computing method as claimed in claim 1, is characterized in that said method comprising the steps of:

1) propylene homo dynamics mathematical model is set up, shown in (1)-(6):

r _P=k _P[M][C*] (1)

-r _tr=k _tr[H ₂] ^0.5[C*] (2)

-r _d=k _d[C*] (3)

$k_p=k_{p0}\exp (-\frac{E_p}{\mathrm{RT}})---\left(4\right)$

$k_{\mathrm{tr}}=k_{\mathrm{tr}0}\exp (-\frac{E_{\mathrm{tr}}}{\mathrm{RT}})---\left(5\right)$

$k_d=k_{d0}\exp (-\frac{E_d}{\mathrm{RT}})---\left(6\right)$

R in formula _p, r _trand r _drepresent polymerization rate of rise, polymeric chain transfer rate and polymerization catalyst deactivation rate respectively; k _prepresent polymerization rate constant of propagation; k _trrepresent polymeric chain transfer rate constant; k _drepresent polymerization catalyst decay rate constants; k _p0, k _tr0and k _d0represent the constant of each corresponding speed equation respectively; E _p, E _trand E _drepresent the energy of activation of each rate equation correspondence reaction respectively; [M] represents propylene monomer concentration; [C ^*] represent catalyst active center's concentration; [H ₂] representing density of hydrogen, R is gas law constant, and T represents the temperature of polyreaction;

Input concrete polymeric reaction temperature, through type (1)-(6) calculate polymerization rate of rise r _p, polymeric chain transfer rate r _trand polymerization catalyst deactivation rate r _d;

2) dynamic mathematical models of bulk propylene polymerization annular-pipe reactor are set up, shown in (7)-(12):

$V_i\frac{d{\left[M\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[M\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[M\right]}_i-r_{\mathrm{pi}}{V}_i---\left(7\right)$

$V_i\frac{d{\left[C^{*}\right]}_i}{\mathrm{dt}}=Q_i^{\mathrm{in}}{\left[C^{*}\right]}_i^{\mathrm{in}}-(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[C^{*}\right]}_i-r_{\mathrm{di}}{V}_i---\left(8\right)$

$V_i\frac{d{\left[H_2\right]}_i}{\mathrm{dt}}=G_{H_2}_i^{\mathrm{in}}/M_{H_2}(Q_i^{\mathrm{out}}+Q_i^{\mathrm{relife}}){\left[H_2\right]}_i-r_{\mathrm{tri}}{V}_i---\left(9\right)$

$V_i{\mathrm{\ρ}}_i\frac{{\mathrm{dw}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{w}_i-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})w_i+r_{\mathrm{pi}}{V}_i{M}_p---\left(10\right)$

$\frac{{\mathrm{dm}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})---\left(11\right)$

$V_i{\mathrm{\ρ}}_i{C}_{\mathrm{pi}}\frac{{\mathrm{dT}}_i}{\mathrm{dt}}=G_i^{\mathrm{in}}{G}_{\mathrm{pi}}^{\mathrm{in}}{T}_{\mathrm{in}}-(G_i^{\mathrm{out}}+G_i^{\mathrm{relife}})C_{\mathrm{pi}}{T}_{\mathrm{out}}+(-{\mathrm{\ΔH}}_{\mathrm{ri}})r_{\mathrm{pi}}{V}_i-{\mathrm{KA}}_i(T_i-T_{\mathrm{ji}})---\left(12\right)$

In formula, A represents the total heat conduction area of reactor, C _prepresent material thermal capacitance, G represents mass flow of materials, represent hydrogen quality flow, K represents the overall heat transfer coefficient of reactor wall, and m represents quality of material in reactor, represent the molal weight of hydrogen, M _prepresent polyacrylic molal weight, Q represents the volumetric flow rate of material, and t represents polymerization time, and V represents volume, and w represents the solid holdup in reactor, and ρ represents material density in reactor, Δ H _rrepresent propylene polymerization enthalpy; Subscript i represents i-th annular-pipe reactor; Subscript in, out and relife represent charging, the discharging of reactor respectively and release;

3) temperature in the reactor using the state equation of high pressure propylene liquid the pressure parameter of inside reactor and dynamic mathematical models to be solved to obtain and material content parameter associate, shown in (13)-(28):

First the density of the propylene monomer of i-th annular-pipe reactor inside is calculated according to formula (13):

${\mathrm{\ρ}}_{M,i}=\frac{m_i(1-w_i)}{V_i-m_i{w}_i/{\mathrm{\ρ}}_{\mathrm{PP}}}---\left(13\right)$

Middle ρ _m,irepresent the density of i-th annular-pipe reactor inner propene;

Secondly, adopt the pressure of Tait equation solution endless tube inside, see formula (14):

$\frac{V_i}{{V_i}^0}=1-D\ln \frac{P_i+\mathrm{EE}}{P^0+\mathrm{EE}}---\left(14\right)$

Arrangement formula (14) obtains formula (15):

$P_{r,i}=\mathrm{Exp}\left[\frac{1}{D}(1-\frac{v_i}{v^0})\right]({P_r}^0+\mathrm{EE})-\mathrm{EE}---\left(15\right)$

(15) in:

$P_{r,i}=\frac{P_i}{P_c}---\left(16\right)$

$v_i=\frac{1}{{\mathrm{\ρ}}_{M,i}}---\left(17\right)$

D=Exp(-2.5355+1.1690ξ+0.1458T _br) (18)

$\mathrm{EE}=(\frac{45.1906}{{T_r}^2}-\frac{45.8849}{T_r}-1)\mathrm{Exp}[2.6583\mathrm{\ξ}+3.7148\ln T_{\mathrm{br}})---\left(19\right)$

$v^0=\frac{{\mathrm{RT}}_c}{P_c}\mathrm{Exp}\{-(1.2310+0.8777\mathrm{\ξ})[1+{(1-T_r)}^{2/7}\left]\right\}---\left(20\right)$

${P_r}^0=\frac{P^0}{P_c}---\left(21\right)$

P in formula (21) ⁰represent the saturation pressure of high pressure propylene liquid, calculated by formula (22):

$P^0=\mathrm{Exp}(A-\frac{B}{T+C})---\left(22\right)$

In formula (22):

A=ln101325+(B/T _c)(T _br+C/T _c) (23)

B=T _c[(1+C/T _c)(T _br+C/T _c)ln(P _c/101325)]/(1-T _br) (24)

C=T _c(0.7F-0.3T _br)/(0.3-F) (25)

F=[(1-T _br)(1+β)ln10]/[ln(P _c/101325)] (26)

T _r=T/T _c(27)

T _br=T _b/T _c(28)

Formula (13)-(28) form the state equation of high-pressure liquid propylene, are calculated [M] in reactor, [C by this state equation ^*], [H ₂], w, m and T value, namely obtain the pressure of annular-pipe reactor inside.

3. computing method as claimed in claim 1, is characterized in that described computing method are applicable to dicyclo pipe and monocycle pipe polymerization technique.

4. computing method as claimed in claim 1, is characterized in that, by changing the reactor scale parameter inputted in the dynamic mathematical models structure of propylene polymerization annular-pipe reactor, calculating the pressure of the annular-pipe reactor inside of random scale.

5. computing method as claimed in claim 1, is characterized in that described computing method are applicable to the calculation of pressure in endless tube under olefin-copolymerization system.