Post on 02-Apr-2015
DIP_simu_04.ppt p. 1
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Rigorous definition: Basic Specification Forms
• Components. Electrolytes
• Reliable design of new components. • Kinetic CSTR reactors.
DIP_simu_04.ppt
DIP_simu_04.ppt p. 2
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Components: Electrolytes
• Template: General with metric units.• Process flow diagram• Setup:
•Title: Absorption of SH2• Specify ‘molar flows’ and ‘mole fractions’ in the stream table.
200 m3/h70ºC, 1 barAIR + 2%MOL SH2
300 kg/h30ºC, 1bar10%W NA2CO3
10 stages
EXAMPLE: Absorption of a stream, mixture of air and SH2, in an aqueous Na2CO3 solution. Check if the concentration of SH2 in the exit stream goes bellow 50 ppm.
DIP_simu_04.ppt p. 3
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
EXAMPLE: Components:
• DefinE: N2, O2, SH2, AGUA, NA2CO3 (AIR can not be defined as such because N2 and O2 have different Henry constants)
• [Elec Wizard]• Include salt formation: OFF• Include water dissociation: ON• True component approach• Review Henry components: N2, O2, SH2, CO2.
DIP_simu_04.ppt p. 4
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
• [Review generated Henry-comps list]: check the content of the GLOBAL group creado in/Componentes/Henry comps• Check:
• /Properties/Specifications• Properties/ Parameters/ Binary interaction/ HENRY-1 , NRTL-1, VLCLK-1• Properties/ Parameters/ Electrolyte Pair/ GMELCC-1, GMELCD-1, GMELCE-1, GMELCN-1
DIP_simu_04.ppt p. 5
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
• Stream 1: 200 m3/h, 70ºC, 1 bar,
AIRE + 2%MOL SH2 Air: O2=0.98*0.21=0.206,
N2=0.98*0.79=0.774• Stream 3:
300 kg/h, 30ºC, 1bar,10%W NA2CO3
• D-110: Configuration: 10 stagesRun
Results Available with errors
DIP_04a.apw
DIP_simu_04.ppt p. 6
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
EXAMPLE: DIP_04b.apw• /D-110/ Setup: Configuration: Convergence=Custom (in order to allow change the algorithm).• /D-110/ Convergence: Basic: Algorithm=Sum-Rates• Run
DIP_04b.apw
• Errors are caused by a wrong choice of the convergence algotithm (default).
• Ask for help for absorbers
DIP_simu_04.ppt p. 7
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Try the alternative suggested solution:• /D-110/ Setup: Configuration: Convergence: Standard• /D-110/ Convergence: Advanced: Absorber=Yes
/Run /Reinitialize [OK] [Aceptar] /Run /Start )
DIP_04c.apw
DIP_simu_04.ppt p. 8
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Initial estimates:• /D-110/Estimates: Temperature
DIP_04d.apw
Run
DIP_simu_04.ppt p. 9
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
10 ppm de SH2/Blocks/D-110/Profiles: Compositions
DIP_simu_04.ppt p. 10
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Design a plant to produce 10.000 Tm/year of monochlorobenzene (MCB). Maximum allowed production of polychlorinated products is 1.000 t/yr.
Literature: Ullmann and Kirk-Othmer encyclopaedias.
• The reaction takes place in a stirred tank with liquid benzene and Cl2 gas. Low temperatures are used (20 - 80ºC).
Benzene chlorination
DIP_simu_04.ppt p. 11
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
BEN
MCB
ODCB PDCB
123TCB 124TCB
1(82)
2(4.16)
3(3.89)
4(1.0) 5
(0.275)6
(0.32)
DIP_simu_04.ppt p. 12
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
New component definition• A non-databank component is defined (123TCB is assumed to be a non-databank
component) by the conventional procedure (not the Wizard). The reliability of the estimated values will be verified later.
• Available data of 123TCB: MW = 181.45, Tb = 218.5
• Define all components: HCL, CL2, BEN, MCB, PDCB, ODCB, 124TCB y 123 TCB.• /Setup /Specifications: Run Type = Property Estimation• /Properties /Estimation /Input /Setup: Estimate all missing parameters.• /Properties /Molecular Structure: 123TCB .................. Define.• /Properties /Parameters /Pure Component: New , Scalar: MW = 181.45, Tb = 218.5 • Run
DIP_MCB_a.apw/Properties /Molecular Structure: General /Properties/Parameters/Pure components/PURE-1: Input
DIP_simu_04.ppt p. 13
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Results may be displayed in /Properties /Estimation /Results, or in /Properties /Parameters /Pure components
/Properties /Estimation /Results: 123TCB /Properties /Parameters /Pure component /PCES-1
• NOTE: After estimation parameters are saved in the databank of the project file. The estimation form may be then disabled. The ‘Reinitialize’ command will no delete these values saved in the databank.
DIP_simu_04.ppt p. 14
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Verification• Can we trust these estimates? The suitability of the methods used by Aspen Plus must be
verified. Estimation methods are used for a databank component with similar molecular structure: 124TCB.
• Two parameters are used to show the procedure: • Critical temperature (TC).• Standard enthalpy of formation for ideal gas (DHFORM).
• Estimate TC y DHFORM by all available methods for 124TCB.
• Compare with values in Aspen databank.
DIP_MCB_b.apw
/Properties /Estimation /Compare: Setup
/Properties /Estimation /Input: Setup
/Properties /Estimation /Input: Pure Component: TC
/Properties /Estimation /Input: Pure Component: DHFORM
DIP_simu_04.ppt p. 15
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
• Many errors are reported:• TC may not be estimated by MANI method becuse of missing parameters: Remove.• Molecular structure is required: Supply.• Run
DIP_MCB_c.apw/Properties /Estimation /Results: Pure Component: 124TCB /Properties /Estimation /Compare Results: Pure Comp: 124TCB
• While TC is correctly predicted by any method, DHFORM is always wrong, especially when the default method is used.
• To continue the simulation disable the estimate input form and change the Run Type to Flowsheet mode.
DIP_simu_04.ppt p. 16
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Reactor design
• Choice of the reactor:
• Considering reactions (mixed in series for MCB and in parallel for CL2) the choice of reactor may be elucidated:
Concentration of interest Performance Flow patternBEN REACTANT HIGH Conversion PFRCL2 REACTANT LOW Selectivity CSTRMCB PRODUCT LOW Selectivity PFR
• A gas-liquid stirred tank reactor will be used for the reaction. Therefore several CSTR in series will be used, where BEN will flow in series, while CL2 will be fed in parallel to all reactors.
• A low proportion of CL2 will also lead to higher selectivity. Furthermore, CL2 should react completely to avoid its mixture with hydrogen chloride at the outlet gas stream.
DIP_simu_04.ppt p. 17
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
• /Properties /Estimation /Input: Setup: Do not estimate any parameters• /Setup/Specifications: Global: Runtype=Flowsheet• /Properties /Specifications: Global: Base Method=NRTL • /Properties /Specifications: Global: Henry components: <New> HC-1 [OK]• /Components /Henry components /HC-1: HCL, CL2• /Properties /Parameters /Binary Interaction /NRTL-1: Input: Estimate all missing parameters by UNIFAC• Process flow diagram:
• Stream 1: 20ºC, 1 bar, 100 kmol/h BEN• Stream 2: 20ºC, 1 bar, 200 kmol/h CL2 (use now CL2 in excess, to avoid errors, since kinetics are CL2 independent. A more realistic flow will be entered later).
• CSTR: 0 bar, 20ºC (lower temperatures increase selectivity: Ea1<Ea2), Vapour-Liquid, Residence Time, 5 hours.
• Reactions: define in /Reactions/Reactions: [New] (R-1, POWERLAW).
DIP_simu_04.ppt p. 18
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
Kinetics• All reactions show first-order kinetics with respect to the aromatic reactive and zero-
order with respect to CL2 (liquid phase is saturated of CL2).
• Parameters are available in literature for the two main reactions (1 and 2). For the other polychlorination reactions the same Ea that in reaction 2 will be assumed. The exponential factor will be calculated from K conversion factors reported in Kirk-Othmer encyclopaedia.
aE
RTi i aromático ir k c k Ae,
Reacción k (s-1) Ea (J/kmol)1 8.800E+07 7.500E+072 1.000E+08 8.300E+073 1.430E+08 8.300E+074 2.420E+07 8.300E+075 6.670E+06 8.300E+076 7.744E+06 8.300E+07
BEN
MCB
ODCB PDCB
123TCB 124TCB
1(82)
2(4.16)
3(3.89)
4(1.0) 5
(0.275)6
(0.32)
DIP_simu_04.ppt p. 19
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
/Blocks/R-130 /Setup: Specifications REACTIONS: /Reactions/Reactions: [New], R-1, Powerlaw
/Reactions/Reactions/R-1: Kinetic
Fill out the form for the 6 reactions
DIP_MCB_d.apw
DIP_simu_04.ppt p. 20
Inte
gra
ted
Pro
cess
Des
ign
(S
imu
lati
on
)
/Data /Results Summary /Streams
RUN
R-310: Results