source: branches/gui/eml/stage_separators/reboiler.mso @ 850

Last change on this file since 850 was 841, checked in by gerson bicca, 14 years ago

improved reboiler model
File size: 14.4 KB
Line 
1#*-------------------------------------------------------------------
2* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
3*
4* This LIBRARY is free software; you can distribute it and/or modify
5* it under the therms of the ALSOC FREE LICENSE as available at
6* http://www.enq.ufrgs.br/alsoc.
7*
8* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
9* from http://www.rps.eng.br Copyright (C) 2002-2004.
10* All rights reserved.
11*
12* EMSO is distributed under the therms of the ALSOC LICENSE as
13* available at http://www.enq.ufrgs.br/alsoc.
14*
15*----------------------------------------------------------------------
16* Author: Paula B. Staudt
17* $Id$
18*--------------------------------------------------------------------*#
19
20using "streams";
21
22Model thermosyphon
23
24ATTRIBUTES
25        Pallete         = true;
26        Icon            = "icon/Thermosyphon";
27        Brief           = "Model of a  Steady State reboiler thermosyphon.";
28        Info            =
29"== ASSUMPTIONS ==
30* perfect mixing of both phases;
31* no thermodynamics equilibrium;
32
33== SET ==
34* the pressure drop in the reboiler;
35* the FlowConstant that relates the Flow through the reboiler and the heat duty
36**      Flow^3 = FlowConstant*InletQ
37
38== SPECIFY ==
39* the InletLiquid stream;
40* the InletQ (the model requires an energy stream, also you can use a controller for setting the heat duty using the heat_flow model)
41OR the outlet temperature (OutletVapour.T);
42
43== OPTIONAL ==
44* the reboiler model has two control ports
45** TI OutletVapour Temperature Indicator;
46** PI OutletVapour Pressure Indicator;
47";     
48
49PARAMETERS
50        outer PP                as Plugin               (Brief = "External Physical Properties", Type="PP");
51        outer NComp     as Integer              (Brief="Number of Components");
52        Pdrop                   as press_delta  (Brief="Pressure Drop in the reboiler", Symbol = "\Delta P");
53        FlowConstant                    as Real (Brief = "Flow Constant");
54        k                       as Real (Brief = "Flow Constant", Hidden = true, Unit='mol^3/(kg*m^2)');
55
56SET
57
58        k = 1*'mol^3/(kg*m^2)';
59       
60VARIABLES
61        in      InletLiquid     as stream                               (Brief="Liquid inlet stream", PosX=0.44, PosY=1, Symbol="_{inL}");
62        out     OutletVapour    as streamPH                             (Brief="Vapour outlet stream", PosX=0, PosY=0.09, Symbol="_{outV}");
63        in      InletQ                  as power                                (Brief="Heat supplied", PosX=1, PosY=0.77, Symbol="Q_{in}", Protected = true);
64       
65        out     TI as control_signal    (Brief="Temperature  Indicator of Reboiler", Protected = true, PosX=1, PosY=0.57);
66        out     PI as control_signal    (Brief="Pressure Indicator of Reboiler", Protected = true, PosX=1, PosY=0.35);
67
68EQUATIONS
69
70"Molar Flow Balance"
71        InletLiquid.F = OutletVapour.F;
72
73"Molar Composition Balance"
74        InletLiquid.z = OutletVapour.z;
75       
76"Energy Balance"
77        InletLiquid.F*InletLiquid.h + InletQ = OutletVapour.F*OutletVapour.h;
78       
79"Pressure Drop"
80        OutletVapour.P = InletLiquid.P - Pdrop;
81
82"Temperature indicator"
83        TI * 'K' = OutletVapour.T;
84
85"Pressure indicator"
86        PI * 'atm' = OutletVapour.P;
87       
88"Flow through the thermosyphon reboiler"
89        OutletVapour.F^3 = FlowConstant*k*InletQ;
90
91end
92
93Model reboilerSteady
94
95ATTRIBUTES
96        Pallete         = true;
97        Icon            = "icon/ReboilerSteady";
98        Brief           = "Model of a  Steady State reboiler with no thermodynamics equilibrium - thermosyphon.";
99        Info            =
100"Model of a  Steady State reboiler with two approaches:
101**Fake Conditions: fake calculation of vaporisation fraction and output temperature, but with a real
102calculation of the output stream enthalpy.
103
104**Flash PH: in the outlet stream a PH Flash is performed to obtain the outlet conditions.
105
106== ASSUMPTIONS ==
107* perfect mixing of both phases;
108* no thermodynamics equilibrium;
109
110== SET ==
111* the option Flash_Calculation
112* the fake Outlet temperature;
113* the fake outlet vapour fraction;
114* the pressure drop in the reboiler;
115* the FlowConstant that relates the Flow through the reboiler and the heat duty
116**      Flow^3 = FlowConstant*InletQ
117
118== SPECIFY ==
119* the InletLiquid stream;
120* the InletQ (the model requires an energy stream, also you can use a controller for setting the heat duty using the heat_flow model)
121OR the outlet temperature (OutletVapour.T);
122
123== OPTIONAL ==
124* the reboiler model has two control ports
125** TI OutletVapour Temperature Indicator;
126** PI OutletVapour Pressure Indicator;
127";     
128
129PARAMETERS
130        outer PP                as Plugin               (Brief = "External Physical Properties", Type="PP");
131        outer NComp     as Integer              (Brief="Number of Components");
132        Flash_Calculation as Switcher (Brief="Flash Calculation", Valid=["Flash_PH","Fake_Conditions"],Default="Fake_Conditions");
133        Pdrop                   as press_delta  (Brief="Pressure Drop in the reboiler", Symbol = "\Delta P");
134        FlowConstant                    as Real (Brief = "Flow Constant");
135        Fake_Temperature                as temperature  (Brief="Fake temperature", Symbol = "T_{fake}");
136        Fake_Vfrac              as fraction     (Brief="Fake vapour fraction", Symbol = "v_{fake}");
137        k                       as Real (Brief = "Flow Constant", Hidden = true, Unit='mol^3/(kg*m^2)');
138
139SET
140
141        k = 1*'mol^3/(kg*m^2)';
142       
143VARIABLES
144        in      InletLiquid     as stream                       (Brief="Liquid inlet stream", PosX=0.345, PosY=1, Symbol="_{inL}", Protected = true);
145        out     OutletVapour    as stream                       (Brief="Vapour outlet stream", PosX=0.17, PosY=0, Symbol="_{outV}", Protected = true);
146        in      InletQ                  as power                        (Brief="Heat supplied", PosX=1, PosY=0.08, Symbol="Q_{in}", Protected = true);
147
148        x(NComp) as fraction    (Brief = "Liquid Molar Fraction",Hidden=true);
149        y(NComp) as fraction    (Brief = "Vapour Molar Fraction",Hidden=true);
150
151        out     TI as control_signal    (Brief="Temperature  Indicator of Reboiler", Protected = true, PosX=0.44, PosY=0);
152        out     PI as control_signal    (Brief="Pressure Indicator of Reboiler", Protected = true, PosX=0.35, PosY=0);
153
154EQUATIONS
155
156"Molar Flow Balance"
157        InletLiquid.F = OutletVapour.F;
158
159"Molar Composition Balance"
160        InletLiquid.z = OutletVapour.z;
161       
162"Energy Balance"
163        InletLiquid.F*InletLiquid.h + InletQ = OutletVapour.F*OutletVapour.h;
164       
165"Pressure Drop"
166        OutletVapour.P = InletLiquid.P - Pdrop;
167
168"Temperature indicator"
169        TI * 'K' = OutletVapour.T;
170
171"Pressure indicator"
172        PI * 'atm' = OutletVapour.P;
173       
174"Flow through the reboiler"
175        OutletVapour.F^3 = FlowConstant*k*InletQ;
176
177switch  Flash_Calculation
178
179        case "Flash_PH":
180
181"Flash Calculation"
182        [OutletVapour.v, x, y] = PP.FlashPH(OutletVapour.P, OutletVapour.h, OutletVapour.z);
183       
184"Enthalpy"
185        OutletVapour.h = (1-OutletVapour.v)*PP.LiquidEnthalpy(OutletVapour.T, OutletVapour.P, x) +
186        OutletVapour.v*PP.VapourEnthalpy(OutletVapour.T, OutletVapour.P, y);
187
188        case "Fake_Conditions":
189
190"Fake Vapourisation Fraction"
191        OutletVapour.v = Fake_Vfrac;
192
193"Fake output temperature"
194        OutletVapour.T = Fake_Temperature;
195
196"Fake Liquid Molar Fraction"
197        x = 1;
198
199 "Fake Vapour Molar Fraction"
200        y = 1;
201
202end
203
204end
205
206Model reboilerReact
207        ATTRIBUTES
208        Pallete         = false;
209        Icon            = "icon/Reboiler";
210        Brief           = "Model of a dynamic reboiler with reaction.";
211        Info            =
212"== Assumptions ==
213* perfect mixing of both phases;
214* thermodynamics equilibrium;
215* no liquid entrainment in the vapour stream;
216* the reaction takes place only in the liquid phase.
217       
218== Specify ==
219* the kinetics variables;
220* the inlet stream;
221* the liquid inlet stream;
222* the outlet flows: OutletVapour.F and OutletLiquid.F;
223* the heat supply.
224
225== Initial Conditions ==
226* the reboiler temperature (OutletLiquid.T);
227* the reboiler liquid level (Level);
228* (NoComps - 1) OutletLiquid (OR OutletVapour) compositions.
229";
230       
231PARAMETERS
232        outer PP as Plugin(Type="PP");
233        outer NComp as Integer;
234        Across as area (Brief="Cross Section Area of reboiler");
235        V as volume (Brief="Total volume of reboiler");
236
237        stoic(NComp) as Real(Brief="Stoichiometric matrix");
238        Hr as energy_mol;
239
240        Initial_Level                           as length               (Brief="Initial Level of liquid phase");
241        Initial_Temperature                     as temperature  (Brief="Initial Temperature of Reboiler");
242        Initial_Composition(NComp)      as fraction     (Brief="Initial Liquid Composition");
243       
244VARIABLES
245in      InletLiquid     as stream                       (Brief="Liquid inlet stream", PosX=0, PosY=0.5254, Symbol="_{inL}");
246out     OutletLiquid as liquid_stream   (Brief="Liquid outlet stream", PosX=0.2413, PosY=1, Symbol="_{outL}");
247out     OutletVapour as vapour_stream   (Brief="Vapour outlet stream", PosX=0.5079, PosY=0, Symbol="_{outV}");
248        InletQ  as power                        (Brief="Heat supplied", PosX=1, PosY=0.6123, Symbol="_{in}");
249
250        M(NComp)        as mol                  (Brief="Molar Holdup in the tray");
251        ML                      as mol                  (Brief="Molar liquid holdup");
252        MV                      as mol                  (Brief="Molar vapour holdup");
253        E                       as energy               (Brief="Total Energy Holdup on tray");
254        vL                      as volume_mol   (Brief="Liquid Molar Volume");
255        vV                      as volume_mol   (Brief="Vapour Molar volume");
256        Level           as length               (Brief="Level of liquid phase");
257        Vol             as volume;
258        rhoV            as dens_mass;
259        r3                      as reaction_mol (Brief = "Reaction resulting ethyl acetate", DisplayUnit = 'mol/l/s');
260        C(NComp)        as conc_mol     (Brief = "Molar concentration", Lower = -1);
261
262INITIAL
263
264        Level                                   = Initial_Level;
265        OutletLiquid.T                          = Initial_Temperature;
266        OutletLiquid.z(1:NComp-1)       = Initial_Composition(1:NComp-1)/sum(Initial_Composition);
267
268EQUATIONS
269"Molar Concentration"
270        OutletLiquid.z = vL * C;
271       
272"Reaction"
273        r3 = exp(-7150*'K'/OutletLiquid.T)*(4.85e4*C(1)*C(2) - 1.23e4*C(3)*C(4)) * 'l/mol/s';
274
275"Component Molar Balance"
276        diff(M)= InletLiquid.F*InletLiquid.z- OutletLiquid.F*OutletLiquid.z - OutletVapour.F*OutletVapour.z + stoic*r3*ML*vL;
277       
278"Energy Balance"
279        diff(E) = InletLiquid.F*InletLiquid.h- OutletLiquid.F*OutletLiquid.h - OutletVapour.F*OutletVapour.h + InletQ + Hr * r3 * vL*ML;
280       
281"Molar Holdup"
282        M = ML*OutletLiquid.z + MV*OutletVapour.z;
283       
284"Energy Holdup"
285        E = ML*OutletLiquid.h + MV*OutletVapour.h - OutletLiquid.P*V;
286       
287"Mol fraction normalisation"
288        sum(OutletLiquid.z)=1.0;
289       
290"Liquid Volume"
291        vL = PP.LiquidVolume(OutletLiquid.T, OutletLiquid.P, OutletLiquid.z);
292
293"Vapour Volume"
294        vV = PP.VapourVolume(OutletVapour.T, OutletVapour.P, OutletVapour.z);   
295
296"Vapour Density"
297        rhoV = PP.VapourDensity(OutletVapour.T, OutletVapour.P, OutletVapour.z);
298       
299"Level of liquid phase"
300        Level = ML*vL/Across;
301
302        Vol = ML*vL;
303       
304"Mechanical Equilibrium"
305        OutletLiquid.P = OutletVapour.P;
306       
307"Thermal Equilibrium"
308        OutletLiquid.T = OutletVapour.T;       
309       
310"Geometry Constraint"
311        V = ML*vL + MV*vV;             
312
313"Chemical Equilibrium"
314        PP.LiquidFugacityCoefficient(OutletLiquid.T, OutletLiquid.P, OutletLiquid.z)*OutletLiquid.z =
315        PP.VapourFugacityCoefficient(OutletVapour.T, OutletVapour.P, OutletVapour.z)*OutletVapour.z;
316
317        sum(OutletLiquid.z)=sum(OutletVapour.z);
318       
319end
320
321Model reboiler
322       
323ATTRIBUTES
324        Pallete = true;
325        Icon    = "icon/Reboiler";
326        Brief   = "Model of a dynamic reboiler - kettle with control.";
327        Info            =
328"== ASSUMPTIONS ==
329* perfect mixing of both phases;
330* thermodynamics equilibrium;
331* no liquid entrainment in the vapour stream.
332       
333== SPECIFY ==
334* the InletLiquid stream;
335* the outlet flows: OutletVapour.F and OutletLiquid.F;
336* the InletQ (the model requires an energy stream, also you can use a controller for setting the heat duty using the heat_flow model).
337
338== OPTIONAL ==
339* the reboiler model has three control ports
340** TI OutletLiquid Temperature Indicator;
341** PI OutletLiquid Pressure Indicator;
342** LI Level Indicator of Reboiler;
343
344== INITIAL CONDITIONS ==
345* Initial_Temperature :  the reboiler temperature (OutletLiquid.T);
346* Levelpercent_Initial : the reboiler liquid level in percent (LI);
347* Initial_Composition : (NoComps) OutletLiquid compositions.
348";     
349       
350PARAMETERS
351        outer PP                as Plugin       (Brief = "External Physical Properties", Type="PP");
352        outer NComp     as Integer      (Brief="Number of Components");
353        Across                  as area         (Brief="Cross Section Area of reboiler");
354        V                               as volume       (Brief="Total volume of reboiler");
355       
356        Levelpercent_Initial            as positive     (Brief="Initial liquid height in Percent", Default = 0.70);
357        Initial_Temperature                     as temperature  (Brief="Initial Temperature of Reboiler");
358        Initial_Composition(NComp)      as positive     (Brief="Initial Liquid Composition",Lower=1E-6);
359
360VARIABLES
361
362in      InletLiquid     as stream                       (Brief="Liquid inlet stream", PosX=0.17, PosY=1, Symbol="_{in}^{Liquid}");
363out     OutletLiquid    as liquid_stream        (Brief="Liquid outlet stream", PosX=0.53, PosY=1, Symbol="_{out}^{Liquid}");
364out     OutletVapour    as vapour_stream        (Brief="Vapour outlet stream", PosX=0.17, PosY=0, Symbol="_{out}^{Vapour}");
365in      InletQ                  as power                        (Brief="Heat supplied", Protected = true, PosX=1, PosY=0.08, Symbol="Q_{in}");
366
367        out     TI as control_signal    (Brief="Temperature  Indicator of Reboiler", Protected = true, PosX=0.44, PosY=0);
368        out     LI as control_signal    (Brief="Level Indicator of Reboiler", Protected = true, PosX=0.53, PosY=0);
369        out     PI as control_signal    (Brief="Pressure Indicator of Reboiler", Protected = true, PosX=0.35, PosY=0);
370       
371        M(NComp)        as mol                  (Brief="Molar Holdup in the tray", Protected = true);
372        ML                      as mol                  (Brief="Molar liquid holdup", Protected = true);
373        MV                      as mol                  (Brief="Molar vapour holdup", Protected = true);
374        E                       as energy               (Brief="Total Energy Holdup on tray", Protected = true);
375        vL                      as volume_mol   (Brief="Liquid Molar Volume", Protected = true);
376        vV                      as volume_mol   (Brief="Vapour Molar volume", Protected = true);
377        rhoV            as dens_mass    (Brief="Vapour Density", Protected = true, Symbol="\rho");
378        Level           as length               (Brief="Level of liquid phase", Protected = true);
379        Pdrop           as press_delta  (Brief = "Pressure Drop", DisplayUnit = 'kPa', Symbol ="\Delta P", Protected=true);
380
381INITIAL
382
383"Initial level Percent"
384        LI = Levelpercent_Initial;
385
386"Initial Temperature"
387        OutletLiquid.T  = Initial_Temperature;
388
389"Initial Composition"
390        OutletLiquid.z(1:NComp-1) = Initial_Composition(1:NComp-1)/sum(Initial_Composition);
391
392EQUATIONS
393
394"Component Molar Balance"
395        diff(M)= InletLiquid.F*InletLiquid.z    - OutletLiquid.F*OutletLiquid.z - OutletVapour.F*OutletVapour.z;
396
397"Energy Balance"
398        diff(E) = InletLiquid.F*InletLiquid.h   - OutletLiquid.F*OutletLiquid.h - OutletVapour.F*OutletVapour.h + InletQ;
399
400"Molar Holdup"
401        M = ML*OutletLiquid.z + MV*OutletVapour.z;
402
403"Energy Holdup"
404        E = ML*OutletLiquid.h + MV*OutletVapour.h - OutletLiquid.P*V;
405
406"Mol Fraction Normalisation"
407        sum(OutletLiquid.z)=1.0;
408
409"Mol fraction Constraint"
410        sum(OutletLiquid.z)=sum(OutletVapour.z);
411
412"Vapour Density"
413        rhoV = PP.VapourDensity(OutletVapour.T, OutletVapour.P, OutletVapour.z);
414
415"Liquid Volume"
416        vL = PP.LiquidVolume(OutletLiquid.T, OutletLiquid.P, OutletLiquid.z);
417
418"Vapour Volume"
419        vV = PP.VapourVolume(OutletVapour.T, OutletVapour.P, OutletVapour.z);
420
421"Chemical Equilibrium"
422        PP.LiquidFugacityCoefficient(OutletLiquid.T, OutletLiquid.P, OutletLiquid.z)*OutletLiquid.z = PP.VapourFugacityCoefficient(OutletVapour.T, OutletVapour.P, OutletVapour.z)*OutletVapour.z;
423
424"Mechanical Equilibrium"
425        OutletLiquid.P = OutletVapour.P;
426
427"Thermal Equilibrium"
428        OutletLiquid.T = OutletVapour.T;
429
430"Pressure Drop"
431        OutletLiquid.P  = InletLiquid.P - Pdrop;
432
433"Geometry Constraint"
434        V = ML*vL + MV*vV;
435
436"Level of liquid phase"
437        Level = ML*vL/Across;
438
439"Temperature Indicator"
440        TI * 'K' = OutletLiquid.T;
441
442"Pressure Indicator"
443        PI * 'atm' = OutletLiquid.P;
444
445"Level indicator"
446        LI*V = Level*Across;
447
448end
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