Presentation on theme: "DIP_simu_04.ppt p. 1 Integrated Process Design (Simulation) Rigorous definition: Basic Specification Forms Components. Electrolytes Reliable design of."— Presentation transcript:
DIP_simu_04.ppt p. 1 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) 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 m 3 /h 70ºC, 1 bar AIR + 2% MOL SH2 300 kg/h 30ºC, 1bar 10% W NA2CO3 10 stages EXAMPLE: Absorption of a stream, mixture of air and SH 2, in an aqueous Na 2 CO 3 solution. Check if the concentration of SH 2 in the exit stream goes bellow 50 ppm.
DIP_simu_04.ppt p. 3 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) [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 Integrated Process Design (Simulation) Stream 1: 200 m 3 /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 stages Run Results Available with errors DIP_04a.apw
DIP_simu_04.ppt p. 6 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) Initial estimates: /D-110/Estimates: Temperature DIP_04d.apw Run
DIP_simu_04.ppt p. 9 Integrated Process Design (Simulation) 10 ppm de SH2 /Blocks/D-110/Profiles: Compositions
DIP_simu_04.ppt p. 10 Integrated Process Design (Simulation) Design a plant to produce Tm/year of monochlorobenzene (MCB). Maximum allowed production of polychlorinated products is t/yr. Literature: Ullmann and Kirk-Othmer encyclopaedias. The reaction takes place in a stirred tank with liquid benzene and Cl 2 gas. Low temperatures are used ( ºC). Benzene chlorination
DIP_simu_04.ppt p. 11 Integrated Process Design (Simulation) BEN MCB ODCBPDCB 123TCB124TCB 1 (82) 2 (4.16) 3 (3.89) 4 (1.0) 5 (0.275) 6 (0.32)
DIP_simu_04.ppt p. 12 Integrated Process Design (Simulation) 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 = , T b = 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 = , T b = Run DIP_MCB_a.apw /Properties /Molecular Structure: General /Properties/Parameters/Pure components/PURE-1: Input
DIP_simu_04.ppt p. 13 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) 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 Integrated Process Design (Simulation) 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: 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. BEN MCB ODCBPDCB 123TCB124TCB 1 (82) 2 (4.16) 3 (3.89) 4 (1.0) 5 (0.275) 6 (0.32)
DIP_simu_04.ppt p. 17 Integrated Process Design (Simulation) /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: 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: E a1
DIP_simu_04.ppt p. 18 Integrated Process Design (Simulation) 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 E a that in reaction 2 will be assumed. The exponential factor will be calculated from K conversion factors reported in Kirk-Othmer encyclopaedia. BEN MCB ODCBPDCB 123TCB124TCB 1 (82) 2 (4.16) 3 (3.89) 4 (1.0) 5 (0.275) 6 (0.32)
DIP_simu_04.ppt p. 19 Integrated Process Design (Simulation) /Blocks/R-130 /Setup: SpecificationsREACTIONS: /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 Integrated Process Design (Simulation) /Data /Results Summary /Streams RUN R-310: Results