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• Anirudh Baviskar

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UNISIM in Process Design Example 1 – Ammonia Process Process Design Course 2017-18 by Mordechai Shacham

UNISIM INSTRUCTIONS WEB SITE:

ftp://ftp.bgu.ac.il/shacham/ProcDes17_18/

Example 1 – Problem Definition In this example a mixture of ammonia and water in the vapor phase, saturated at 250 psia and containing 80 wt% ammonia, is passed through a condenser at a flow rate of 10,000 Ib/hr, where heat is removed at the rate of 5.8 x 106 Btu/hr. Its effluent is expanded to a pressure of 150 psia and fed into a flash vessel (V100). Neglecting the heat loss from the equipment to the surroundings and the pressure drop in the condenser, it is desired to determine the composition of the liquid stream leaving the separator. Use SRK fluid package.

Selection of the Compounds Present in the Process

Selection of Property Package SRK Simulation Basis Manager –> Fluid Package

Specification of the FEED stream From “Simulation Basis Manager” -> “Enter Simulation Environ..” “Flowsheet” dropdown menu -> Add Stream

Specification of the Cooler “CONDENSER” “Flowsheet” dropdown menu -> Add “Operation”. Select “Cooler”

Note: +Q not -Q

Definition of the Expander Valve Doublecklick on the “Valve” icon Its effluent is expanded to a pressure of 150 psia and fed into a flash vessel (V-100)

Definition of the Flash Vessel V-100 Double Click on the Separator Icon

Ammonia Separation Process – Final PFD

Ammonia Separation Process – Final Worksheet

Example 2 –Toluene Production - Problem Definition Toluene is produced from n-heptane by dehydrogenation over a CrZO3 catalyst adsorbed on AlzO3: n-heptane is heated from 65 to 800°F in a SUPERHEATER, and then fed to a CATALYTIC REACTOR, which operates isothermally and converts 15 mol % of the n-heptane to toluene. Its effluent is cooled to 65°F and fed to a separator. Assuming that the feed flow rate is 100 lbmol/hr and all of the units operate at atmospheric pressure, use UNISIM to determine the species flow rates in every stream. Use Peng-Robinson fluid package.

Selection of the Compounds Present in the Process

Selection of Property Package Peng-Robinson

Specification of the FEED stream From simulation basis manager “Enter Simulation Environment” “Flowsheet” dropdown menu -> Add Stream

Specification of the Heater “SUPERHEATER” “Flowsheet” dropdown menu -> Add “Operation”. Select “Heater”

Definition of Reaction sets “Flowsheet” dropdown menu -> “Reaction Package”

Definition of the “CATALYTIC REACTOR” “Flowsheet” dropdown menu -> Add “Operation”. Select “Conversion Reactor”

Definition of the Condenser C-1 Double Click on the Cooler Icon

Definition of the Flash Vessel V-1 Double Click on the Separator Icon

Toluene Process – Final PFD

Toluene Process – Final Worksheet

Example 3 – Production of Ethyl Chloride - Problem Definition Ethyl chloride is produced by the gas-phase reaction of HCI with ethylene over a copper chloride catalyst supported on silica: C2H4 + HCI →C2H5CI In the process shown in the Figure, the feed stream is composed of 50 mol% HCI, 48 mol% C2H4, and 2 mol% N2 at 100 kmol/hr, 25°C, and 1 atm. Since the reaction achieves only 90 mol% conversion, the ethyl chloride product is separated from the unreacted reagents, and the latter are recycled. The separation is achieved using a distillation column, where it is assumed that a perfect separation is achievable. The process is operated at atmospheric pressure, and pressure drops are ignored. To prevent the accumulation of inerts in the system, 10% of the feed to unit S-1 is withdrawn in a purge stream, Use Peng-Robinson fluid package.

Example 3 – Problem Definition C2H4 + HCI →C2H5CI 90 % mol conversion S-1 – 10 % mol of S4 to W

S4

T=25 ˚C P = 1atm Peng-Robinson fluid package

D-1 – Perfect Separation

Selection of the Compounds and Property Package

S4

Specification of the FEED stream From simulation basis manager “Enter Simulation Environment” “Flowsheet” dropdown menu -> Add Stream

Specification of the Recycle (R*) stream “Flowsheet” dropdown menu -> Add Stream

Specification of the Mixer “M-”1 Doubleclick on the “Mixer” Icon

Definition of Reaction sets “Flowsheet” dropdown menu -> “Reaction Package”

Definition of the “CATALYTIC REACTOR” “Flowsheet” dropdown menu -> Add “Operation”. Select “Conversion Reactor”

Definition of the Component Splitter D-1 Flowsheet” dropdown menu -> Add “Operation”. Select “Component Splitter” S4

Definition of TEE S-1 Flowsheet” dropdown menu -> Add “Operation”. Select “Tee” S4

Definition of Recycle Block R-1 Flowsheet” dropdown menu -> Add “Operation”. Select “Recycle” S4

Ethyl Chloride Process – Final PFD

Ethyl Chloride Process – Final Worksheet