23/03/2013
Reactores Químicos en Aspen Plus Diplomado en Energía Modulo V 22 de Marzo del 2013 UAM Cuajimalpa ‐
Asociación Nacional de la Industria Química
REACTORES QUIMICOS MODELO
DESCRIPCIÓN
PROPÓSITO
RSTOIC reactor estequiometrico modela reactores estequiometricos con extensión o conversión especificada
RYIELD
REQUIL
RGIBBS
RCSTR
RPLUG
R BA BAT CH CH
•
UTILIDAD reactores donde la cinéticaes desconocidao poco importanteperola este importanteperola estequiome quiometriay triay exte extensión nsión son conocidas reactoresdondela reacto resdondela este estequiome quiometriay triay la cinéticason desconocidas o poco importantes perola distribución de rendimientoes conocida
reactor de produccion
modela reactor con una produccion especifica
reactor de equilibrio
realiza realiza equilibrioquímico equilibrioquímico y de fases por cálculos estequiometricos
reactores con simultáneos equilibrios químicos y defase defasess
reactor de equilibrio con minimización minimización de energía de GIBBS
realiza realiza equilibrioquímico equilibrioquímico y de fases por minimización de la energía de GIBBS
reactores con simultáneos multáneos equilibrios químicos y de fases. Calculo de equilibrios de fase parasoluciones con sólidos y sistemas vapor vapor‐‐liquido liquido‐‐solido
Reactor continuo de tanqueagitado
modela reactor de tanqueagitado
reactores detanque agitados con una,dos, o tres fases con reacciones de equilibrio o controladasen alguna fase basado en estequiometriao cinética
Reactor de flujo de pistón
modela reactor de flujo de pistón
R ea ea ct ct or or Ba Batc tch h
model mod elareac areacto tore ress batch o semicontinuos
reactores de flujo pistón con una, dos, o tres fases con reacciones de equilibrio o controladasen alguna fase basado en estequiometriao cinética reactores batcho semico semicontinu ntinuoscon oscon una, dos, o tres fases con reacciones reacciones de equilibrio o controladas en algunafase basado en estequiometriao estequiometriao cinética
No es necesario especificar calores de reacción, porque Aspen Plus usa la entalpía elemental del estado de referencia de calor de formación del componente.
Asociación Nacional de la Industria Química
1
23/03/2013
Modelos de Reactores en Aspen Plus Model
Stoichiometry Kinetics
Rigorous
Feed
RSTOIC
Yes
No
No
Any
RYIELD
No
No
No
Any
REQUIL
No
No
No
Any
RGIBBS
No
No
No
Any
RBATCH
Yes
Yes
Yes
1
RCSTR
Yes
Yes
Yes
Any
RPLUG
Yes
Yes
Yes
1
Asociación Nacional de la Industria Química
RSTOIC Use RStoic to model a reactor when: Reaction kinetics are unknown or unimportant and Stoichiometry and the molar extent or conversion is known for each reaction RStoic can model reactions occurring simultaneously or sequentially. In addition, RStoic can perform product selectivity and heat of reaction calculations. ∙
∙
Material Streams Inlet At least one material stream Outlet One product stream One water decant stream (optional)
Heat Stream Inlet Any number of heat streams (optional) RStoic uses the sum of the inlet heat streams as the heat duty specification, if you do not specify an outlet heat stream. Outlet One heat stream (optional) The value of the outlet heat stream is the net heat duty (sum of the inlet heat streams minus the calculated heat duty) for the reactor.
Asociación Nacional de la Industria Química
2
23/03/2013
RYIELD Use RYield to model a reactor when: Reaction stoichiometry is unknown or unimportant Reaction kinetics are unknown or unimportant Yield distribution is known You must specify the yields (per mass of total feed, excluding any inert components) for the products or calculate them in a user supplied Fortran subroutine. RYield normalizes the yields to maintain a mass balance. RYield can model one , two , and three phase reactors. ∙
∙
∙
‐
‐
‐
‐
Material Streams Inlet At least one material stream Outlet One product stream One water decant stream (optional)
Heat Streams Inlet Any number of heat streams (optional) Outlet One heat stream (optional) Asociación Nacional de la Industria Química
REQUIL Use REquil to model a reactor when: Reaction stoichiometry is known and Some or all reactions reach chemical equilibrium. REquil calculates simultaneous phase and chemical equilibrium. REquil allows restricted chemical equilibrium specifications for reactions that do not reach equilibrium. REquil can model one and two phase reactors. ∙
∙
‐
‐
Material Streams Inlet At least one material stream Outlet One material stream for the vapor phase One material stream for the liquid phase
Heat Streams Inlet Any number of heat streams (optional) Outlet One heat stream (optional) Asociación Nacional de la Industria Química
3
23/03/2013
RGIBBS RGibbs uses Gibbs free energy minimization with phase splitting to calculate equilibrium. RGibbs does not require that you specify the reaction stoichiometry. Use RGibbs to model reactors with: Single phase (vapor or liquid) chemical equilibrium Phase equilibrium (an optional vapor and any number of liquid phases) with no chemical reactions Phase and/or chemical equilibrium with solid solution phases Simultaneous phase and chemical equilibrium RGibbs can also calculate the chemical equilibria between any number of conventional solid components and the fluid phases. RGibbs also allows restricted equilibrium specifications for systems that do not reach complete equilibrium. ∙
∙
∙
∙
Material Streams Inlet At least one material stream Outlet At least one material stream
Asociación Nacional de la Industria Química
RCSTR RCSTR rigorously models continuous stirred tank reactors. RCSTR can model one , two , or t hree phase reactors. RCSTR assumes perfect mixing in the reactor, that is, the reactor contents have the same properties and composition as the outlet stream. RCSTR handles kinetic and equilibrium reactions as well as reactions involving solids. You can provide the reaction kinetics through the built in Reactions models or through a user defined Fortran subroutine. ‐
‐
‐
‐
‐
Material Streams Inlet At least one material stream Outlet One material stream
Heat Streams Inlet Any number of heat streams (optional) Outlet One heat stream (optional)
Asociación Nacional de la Industria Química
4
23/03/2013
RPLUG RPlug is a rigorous model for plug flow reactors. RPlug assumes that perfect mixing occurs in the radial direction and that no mixing occurs in the axial direction. RPlug can model one , two , or three phase reactors. You can also use RPlug to model reactors with coolant streams (co current or counter current). RPlug handles kinetic reactions, including reactions involving solids. You must know the reaction kinetics when you use RPlug to model a reactor. You can provide the reaction kinetics through the built in Reactions models or through a user defined Fortran subroutine. ‐
‐
‐
‐
‐
‐
‐
Material Streams Inlet One material feed stream One coolant stream (optional) Outlet One material product stream One coolant stream (optional)
Heat Streams Inlet No inlet heat streams Outlet One heat stream (optional) for the reactor heat duty. Use the heat outlet stream only for reactors without a coolant stream.
Asociación Nacional de la Industria Química
RBATCH RBatch is a rigorous model for batch or semi batch reactors. Use RBatch when you know the kinetics of the reactions taking place. You can specify any number of continuous feed streams. A continuous vent is optional. The reaction runs until it reaches a stop criterion that you specify. Batch operations are unsteady state processes. RBatch uses holding tanks and your specified cycle times to provide an interface between the discrete operations of the batch reactor and the continuous streams used by other models. RBatch can model one , two , or three phase reactors. ‐
‐
‐
‐
‐
Material Streams Inlet One batch charge stream (required) One or more continuous feed streams for semi batch reactors (optional) Outlet One product stream (required) One vent stream for semi batch reactors (optional) ‐
‐
Heat Streams Inlet No inlet heat streams Outlet One heat stream (optional) Asociación Nacional de la Industria Química
5
23/03/2013
Resumen •
Hay 7 modelos de reactor incorporados en Aspen Plus; RSTOIC, RYIELD, REQUIL, RGIBBS, RPLUG, RCSTR y RBATCH. RPLUG, RCSTR y RBATCH modelos son rigurosos de los reactores de flujo pistón (tubulares), CSTR y por lotes, respectivamente.
•
•
•
•
•
•
RSTOICH se debe utilizar en los casos en que la estequiometría se conoce, pero la
cinética de la reacción es o desconocida o poco importante. Si se dan los dos casos, la cinética de reacción y loa estequiometría son desconocidas entonces deben ser usarse RYIELD en las simulaciones. Para cálculos de una sola fase en equilibrio químico fase de equilibrio o equilibrio químico y de fases simultáneos la elección del modelo de reactor de debe ser REQUIL o RGIBBS. REQUIL basa sus cálculos en la solución simultánea de la estequiometria y el equilibrio de fases, mientras que RGIBBS resuelve su modelo minimizando la energía libre de Gibbs. Todos los modelos de reactores, excepto RPLUG y RBATCH pueden tener cualquier número de corrientes de alimentación. Estas corrientes se mezclan internamente. Los modelos rigurosos pueden incorporar las cinéticas tipo ley de la potencia o Langmuir Hinschelwood Hougen Watson (incluídas en Aspen) o cinéticas especificados por el usuario. Estas se pueden definir en subrutinas escritas en Fortran o en hojas de cálculo de Excel. ‐
•
‐
‐
Asociación Nacional de la Industria Química
Velocidades de reacción
Asociación Nacional de la Industria Química
6
23/03/2013
CINETICA DE RECCIONES DE LANGMUIR HINSHELWOOD HOUGEN WATSON (LHHW) ‐
‐
‐
Asociación Nacional de la Industria Química
7
