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PROCESS CONTROL DESIGN CRITERIA. DESIGNS FOR SPECIFIC SERVICES. DISTILLATION CONTROL. PRESSURE CONTROL COLUMNS ARE OPERATED AT CONSTANT PRESSURE PRESSURE CONTROL CAN BE UTILIZE VACUUM CONTROL FOR SUBAMBIENT OPERATION, WITH CONDENSATE TEMPERATURE CONTROL TO ASSURE TOTAL CONDENSATION
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PROCESS CONTROL DESIGN CRITERIA DESIGNS FOR SPECIFIC SERVICES
DISTILLATION CONTROL • PRESSURE CONTROL • COLUMNS ARE OPERATED AT CONSTANT PRESSURE • PRESSURE CONTROL CAN BE UTILIZE • VACUUM CONTROL FOR SUBAMBIENT OPERATION, WITH CONDENSATE TEMPERATURE CONTROL TO ASSURE TOTAL CONDENSATION • CONDENSER CONTROL FOR PRESSURIZED COLUMNS, WITH PURGE TO ELIMINATE ACCUMULATION OF NON-CONDENSIBLE COMPONENTS http://coweb.cc.gatech.edu/process/uploads/distillationcolumn.gif
TC PC VACUUM SYSTEM CONDENSER OVERPRESSURE PURGE VALVE SUB-AMBIENT DISTILLATION SYSTEM DISTILLATE RECEIVER COLUMN TYPICAL ARRANGEMENT FOR DISTILLATION PRESSURE CONTROL FOR SUB- AMBIENT SYSTEM
PC CONDENSER OVERPRESSURE PURGE VALVE AMBIENT OR SUPER –AMBIENT DISTILLATION SYSTEM DISTILLATE RECEIVER COLUMN TYPICAL ARRANGEMENT FOR DISTILLATION PRESSURE CONTROL FOR ABOVE AMBIENT SYSTEM
REFLUX CONTROL • USE LEVEL CONTROL ON DISTILLATE RECEIVER TO CONTROL DISTILLATE RATE • USE FLOW-FLOW RATIO CONTROL TO CONTROL REFLUX RATE • NOTE THAT THIS REFLUX RATIO SETPOINT CAN BE ADJUSTED USING AN ANALYZER SENSOR • USE TEMPERATURE CONTROL FOR CONDENSER WATER FLOW
LC COLUMN STEAM TC BOIL-UP CONTROL FOR DISTILLATION SYSTEM BOTTOMS REBOILER BOILUP CONTROL
BOILUP CONTROL • THE SUMP LEVEL CONTROL SERVES TO SET THE BOTTOMS FLOW RATE • THE VAPORIZATION RATE CAN BE CONTROLLED USING THE LOWER TRAY TEMPERATURE • OTHER OPTIONS ARE AVAILABLE www.aspentech.com/publication_files/An_Integrated_Approach_for_Distillation_Column_Control.pdf
REACTOR HEAT EXCHANGER CIRCULATION PUMP TC HEATING OR COOLING MEDIA REACTOR CONTROL
REACTOR CONTROL • CSTR • FOR EXOTHERMIC OR ENDOTHERMIC REACTIONS, LOCATE THE HEAT TRANSFER UNIT OUTSIDE THE REACTOR AND USE A JACKET OR AN INTERNAL COIL • PFR • CONTROLLED LIKE A HEAT EXCHANGER
I FS B A S PUMP FLOW CONTROLS • PUMPS SHOULD INCLUDE A SWITCH TO ACTIVATE/SWITCH THE SPARE UNIT LL
I I RD LL HH TANK RELIEF DESIGNS • TANKS SHOULD BE ALARMED FOR LEVEL AND/OR PRESSURE AND/OR TEMPERATURE • PRESSURE RELIEF SHOULD BE PROVIDED FOR TANKS CONTAINING HAZARDOUS MATERIALS TO FLARE PS HH LS INERT GAS
Cl2 RXTR PLC USE PLCs FOR BATCH OPERATIONS • USE RECIPE FROM SUPERPRO
BATCH CONTROL DESIGN METHODS – ISA S88 • ISA S88 was developed to provide a structure for design of Batch Control systems. • S88 defines hierarchical recipe management and process segmentation frameworks, which separate products from the processes that make them. The standard enables reuse and flexibility of equipment, and provides a structure for coordinating and integrating recipe-related information across the traditional ERP, MES, and control domains. (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)
S88 - DEFINITIONS • Separate the recipe from equipment control • (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)
S88 - DEFINITIONS • Everything breaks into pieces • (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)
RECIPE DEFINITIONS • Recipes are provided for different levels • (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)
RECIPE EXAMPLE • Recipe for making ice cream • (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)
RECIPE EXAMPLE • Ice cream Recipe • (http://www.batchcontrol.com/s88/01_tutorial/03-whatiss88.shtml)