Potential
Potential
Reach Your Reach YourTrue
True
Full-Scale Plant Modeling Workshop
Full-Scale Plant Modeling Workshop
Objective:
Objective:
Practice and apply many of the techniques used in this
Practice and apply many of the techniques used in this
course and learn how to best approach modeling
course and learn how to best approach modeling
projects
Full-Scale Plant Modeling Workshop
Objective: Model a methanol plant.
The process being modeled is a methanol plant. The
basic feed streams to the plant are Natural Gas, Carbon
Dioxide (assumed to be taken from a nearby Ammonia
Plant) and Water. The aim is to achieve the methanol
production rate of approximately 62,000 kg/hr, at a purity
of at least 99.95 % wt.
This is a large flowsheet that would take an experienced
engineer more than an afternoon to complete. Start
building the flowsheet and think about how you would
work to complete the project.
General Guidelines
•
Build the flowsheet one section at a time.
•
Simplify whenever possible. Complexity can always be
added later.
•
Investigate the physical properties.
Use Analysis.
Check if binary parameters are available.
Check for two liquid phases.
Use an appropriate equation of state for the portions of
the flowsheet involving gases and use an activity
coefficient model for the sections where non-ideal
liquids may be present.
Full-Scale Plant Modeling Workshop
FURNACE Fuel Air MEOHRXR SPLIT1 MIX2 E121 COOL4 FL3 SYNCOMP FL1 FL2 COOL1 COOL3 COOL2 BOILER E122 CIRC E124 E223 FL4 SPLIT2 FL5 M4 MKWATER TOPPING REFINING M2 SATURATE FEEDHTR REFORMER NATGAS H2OCIRC MKUPST CH4COMP CO2 CO2COMP M1Part 1: Front-End Section
M2 SATURATE FEEDHTR REFORMER NATGAS H2OCIRC MKUPST CH4COMP CO2 CO2COMP From Furnace To BOILER M1Part 1: Front-End Section
(Continued)
1. Front-end Section
Carbon Dioxide Stream – CO2
•
Temperature = 43 C•
Pressure = 1.4 bar•
Flow = 24823 kg/hr•
Mole Fraction
CO2 - 0.9253
H2 - 0.0094
H2O - 0.0606
CH4 - 0.0019
N2 - 0.0028Natural Gas Stream - NATGAS
•
Temperature = 26 C•
Pressure = 21.7 bar•
Flow = 29952 kg/hr•
Mole Fraction
CO2 - 0.0059
CH4 - 0.9539
N2 - 0.0008
C2H6 - 0.0391
C3H8 - 0.0003Circulation Water - H2OCIRC
•
Pure water stream•
Flow = 410000 kg/hr•
Temperature = 195 C•
Pressure = 26 bar Makeup Steam - MKUPST•
Stream of pure steam•
Flow = 40000 kg/hr•
Pressure = 26 bar•
Vapor Fraction = 1•
Adjust the makeup steam flow to achieve a desired steam to methane molar ratio of 2.8 in the Reformer feed REFFEED.Part 1: Front-End Section
(Continued)
Carbon Dioxide Compressor - CO2COMP
•
Discharge Pressure = 27.5 bar•
Compressor Type = 2 stageNatural Gas Compressor - CH4COMP
•
Discharge Pressure = 27.5 bar•
Compressor Type = single stageReformer Process Side Feed Stream Pre-Heater - FEEDHTR
•
Exit Temperature = 560 C•
Pressure drop = 0Saturation Column - SATURATE
•
1.5 inch metal pall ring packing.•
Estimated HETP = 10 x 1.5 inches = 381 mm•
Height of Packing = 15 meters•
No condenser and no reboiler. Reformer Reactor - REFORMER•
Consists of two parts: the Furnace portion and the Steam Reforming portion•
Exit Temperature of the Steam Reforming portion = 860 CPart 2: Heat Recovery Section
COOL4 FL3 SYNCOMP FL1 FL2 COOL1 COOL3 COOL2 BOILER To TOPPING To REFINING To Methanol Loop From ReformerPart 2: Heat Recovery Section
(Continued)
2. Heat Recovery Section
•
This section consists of a series of heat exchangers and flash vessels used to recover the available energy and water in the Reformed Gas stream.BOILER
•
Exit temperature = 166 C•
Exit Pressure= 18 bar COOL1•
Exit temperature = 136 C•
Exit Pressure = 18 bar COOL2•
Exit temperature = 104 C•
Exit Pressure = 17.9 bar COOL3•
Exit temperature = 85 C•
Pressure Drop = 0.1 bar COOL4•
Exit temperature = 40 C•
Exit Pressure = 17.6 barFL1
•
Pressure Drop = 0 bar•
Heat Duty = 0 MMkcal/hr FL2•
Exit Pressure = 17.7 bar•
Heat Duty = 0 MMkcal/hr FL3•
Exit Pressure = 17.4 bar•
Heat Duty = 0 MMkcal/hr SYNCOM•
Two Stage Polytropic compressor•
Discharge Pressure = 82.5 barPart 3: Methanol Synthesis Section
MEOHRXR SPLIT1 MIX2 E121 From SYNCOMP E122 CIRC E124 E223 FL4 SPLIT2 To FurnacePart 3: Methanol Synthesis Section
(Continued)
3. Methanol Synthesis Loop Section
Methanol Reactor - MEOHRXR
•
Tube cooled reactor•
Exit Temperature from the tubes = 240 C•
No pressure drop across the reactor•
Reactions− CO + H2O <-> CO2 + H2 (Equilibrium)
− CO2 + 3H2 <-> CH3OH + H2O (+15 C Temperature Approach) − 2CH3OH <-> DIMETHYLETHER + H2O (Molar extent 0.2kmol/hr)
− 4CO + 8H2 <-> N-BUTANOL + 3H2O (Molar extent 0.8kmol/hr) − 3CO + 5H2 <-> ACETONE + 2H2O (Molar extent 0.3kmol/hr)
E121
•
Exit Temperature - 150 C•
Exit Pressure - 81 bar E122•
Cold Side Exit Temperature - 120 C E223•
Exit Temperature - 60 C•
Exit Pressure - 77.3 bar E124•
Exit Temperature - 45 C•
Exit Pressure - 75.6 barFL4
• Exit Pressure = 75.6 bar • Heat Duty = 0 MMkcal/hr CIRC
• Single stage compressor • Discharge Pressure = 83 bar • Discharge Temperature = 55 C SPLIT1
• Split Fraction = 0.8 to stream to E121 SPLIT2
Part 4: Distillation Section
FL5 M4 MKWATER TOPPING REFINING From COOL2 To Furnace From COOL1 From FL4Part 4: Distillation Section
(Continued)
4. Distillation Section
Makeup Steam - MKWATER
•
Stream of pure water•
Flow = 10000 kg/hr•
Pressure = 5 bar•
Temperature = 40 C•
Adjust the make-up water flow (stream MKWATER) to the CRUDE stream to achieve a stream composition of 23 wt.% of water in the stream feeding the Topping column (stream TOPFEED) to achieve 100 ppm methanol in the Refining column BTMS stream.Topping Column - TOPPING
•
Number of Stages = 51 (including condenser and reboiler)•
Condenser Type = Partial Vapor/Liquid•
Feed stage = 14•
Distillate has both liquid and vapor streams•
Distillate rate = 1400 kg/hr•
Pressure profile: stage 1 = 1.5 bar and stage 51 = 1.8 bar•
Distillate vapor fraction = 99 mol%•
Stage 2 heat duty = -7 Mmkcal/hr•
Stage 51 heat duty Specified by the heat stream•
Reboiler heat duty is provided via a heat stream from block COOL2•
Boil-up Ratio is approximately 0.52•
Valve trays•
The column has two condensers. To represent the liquid flow connections a pumparound can be used between stage 1 and 3.Part 4: Distillation Section
(Continued)
Distillation Section (Continued)
Refining Column - REFINING
•
Number of Stages = 95 (including condenser and reboiler)•
Condenser Type = Total•
Distillate Rate = 1 kg/hr•
Feed stage = 60•
Liquid Product sidedraw from Stage 4 @ 62000 kg/hr (Stream name – PRODUCT)•
Liquid Product sidedraw from Stage 83 @ 550 kg/hr (Stream name – FUSELOIL)•
Reflux rate = 188765 kg/hr•
Pressure profile: stage 1= 1.5bar and stage 95=2bar•
Reboiler heat duty is provided via a conventional reboiler supplemented by a heat stream from a heater block to stage 95•
Boil-up Ratio is approximately 4.8•
Valve trays•
To meet environmental regulations, the bottoms stream must contain no more than 100ppm by weight of methanol as this stream is to be dumped to a nearby river.FL5
•
Exit Pressure 5 bar•
Heat Duty 0 MMkcal/hr M4Part 5: Furnace Section
FURNACE Fuel Air From FL5 From SPLIT2 To REFORMERPart 5: Furnace Section
(Continued)
5. Furnace Section
Air to Furnace - AIR
