PFD_P&ID.pdf
- 1. Process Diagrams OBJECTIVES After studying this chapter, the student will be able to: • Review process diagram symbols. • Describe the use of process diagrams and the information they contain. • Draw a process flow diagram. • Draw a process and instrument drawing. • Describe the various process equipment relationships. 251 MASTER ➁ 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 251
- 2. MASTER ➁ Key Terms Electrical drawings—symbols and diagrams that depict an electrical process. Elevation drawings—a graphical representation that shows the location of process equipment in relation to existing structures and ground level. Equipment location drawings—show the exact floor plan for location of equipment in relation to the plan’s physical boundaries. Flow diagram—a simplified sketch that uses symbols to identify instruments and vessels and to describe the primary flow path through a unit. Foundation drawings—concrete, wire mesh, and steel specifications that identify width, depth, and thickness of footings, support beams, and foundation. Legends—a document used to define symbols, abbreviations, prefixes, and specialized equipment. Process and instrument drawing (P&ID)—a complex diagram that uses process symbols to describe a process unit; also called piping and instrumentation drawing. Chapter 12 ● Process Diagrams 252 Types of Process Diagrams Process diagrams can be broken down into two major categories: process flow diagrams (PFDs) and process and instrument drawings (P&IDs), sometimes called piping and instrumentation drawings. A flow diagram is a simple illustration that uses process symbols to describe the primary flow path through a unit. A process flow diagram provides a quick snapshot of the operating unit. Flow diagrams include all primary equipment and flows. A technician can use this document to trace the primary flow of chemicals through the unit. Secondary or minor flows are not included. Complex con- trol loops and instrumentation are not included. The flow diagram is used for visitor information and new employee training. A process and instrument drawing is more complex. The P&ID includes a graphic representation of the equipment, piping, and instrumentation. Mod- ern process control can be clearly inserted into the drawing to provide a process technician with a complete picture of electronic and instrument systems. Process operators can look at their process and see how the en- gineering department has automated the unit. Pressure, temperature, flow, and level control loops are all included on the unit P&ID. Basic Instrument Symbols Process technicians use P&IDs to identify all of the equipment, instru- ments, and piping found in their units. New technicians use these drawings 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 252
- 3. Basic Instrument Symbols 253 MASTER ➁ Globe Valve Gate Valve Reboiler Three-Way Valve Check Valve Shell & Tube Heat Exchanger Bleeder Valves Pneumatic Operated Centrifugal Pumps Rotary Compressor Manual Operated Valve Gauge Vacuum Pump Reciprocating Compressor Turbine Orifice Pneumatic Operated Butterfly Valve Compressor & Silencers Single Pass Heat Exchanger U-Tube Heat Exchanger Safety PSV Butterfly Ball Solenoid Valve CLOSED S VALVES PUMPS & TURBINE COMPRESSORS HEAT EXCHANGERS Bin Tank Tower Drum or Condenser Mixer Mixing Reactor Minor Process Pneumatic Hydraulic Capillary Tubing Electromagnetic Signal Electric X X X X X X L L L VESSELS Furnace Liquid Ring Compressor Hairpin Exchanger Condenser Heater Centrifugal Compressor Tower with Packing Centrifugal Compressor (Turbine Driven) T Gear Pump Vertical Screw Pump Rotameter Four-Way Needle Angle LINE SYMBOLS Major Process Future Equipment Plug Diaphragm M H Hydraulic Back Pressure Regulator Back Pressure Regulator Motor Relief PRV Induced-Draft Cooling Tower Forced-Draft Cooling Tower Flow Indicator Flow Transmitter Flow Recorder Pressure Indicator Pressure Transmitter Pressure Recording Controller FI FT FR PI PT PRC Temp Indicator Temp Transmitter Temp Recorder Level Indicator Level Transmitter Level Controller TI TT TR LI LT LC Figure 12.1a Process and Instrument Symbols 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 253
- 4. during their initial training period. Knowing and recognizing these symbols is important for a new technician.The chemical processing industry has as- signed a symbol for each type of valve, pump, compressor, steam turbine, heat exchanger, cooling tower, basic instrumentation, reactor, distillation column, furnace, and boiler (Figure 12.1). There are symbols to represent major and minor process lines and pneumatic, hydraulic, or electric lines, and there is a wide variety of electrical symbols. Flow Diagrams New technicians are required to study a simple flow diagram of their as- signed operating system. Process flow diagrams typically include the major equipment and piping path the process takes through the unit. As operators learn more about symbols and diagrams, they graduate to the much more complex P&IDs. Chapter 12 ● Process Diagrams 254 MASTER ➁ Flow Indicator Flow Transmitter Flow Recorder Pressure Indicator Pressure Transmitter FI FT FR PI PT Temp Indicator Temp Transmitter Temp Recorder Level Indicator Level Transmitter Level Controller TI TT TR LI LT LC F I C 55 Variable Being Measured Remote Location (board mounted) Control Loop Instrument Remote Location (behind control panel) Field Mounted LR Level Recorder TC Temp Controller PR Pressure Recorder Pressure Controller PC 65 55 55 65 65 55 Flow Controller FC PIC PRC LA 105 40 25 I P Transducer Pressure Indicating Controller Pressure Recording Controller Level Alarm FE Flow Element TE Temperature Element LG Level Gauge AT Analyzer Transmitter What It Does Figure 12.1b Process and Instrument Symbols (continued) 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 254
- 5. Some symbols are common among plants; others differ from plant to plant. Some standardization of process symbols and diagrams is taking place. The symbols used in this chapter reflect a wide variety of petrochemical and refinery operations. Figure 12.2 is a PFD that shows the basic relationships and flow paths found in a process unit. It is easier to understand a simple flow diagram if it is broken down into sections: feed, preheating, the process, and the final products. This simple left-to-right approach allows a technician to identify where the process starts and where it will eventually end. The feed section includes the feed tanks, mixers, piping, and valves. In the second step, the process flow is gradually heated for processing. This section includes heat exchangers and furnaces. In the third section, the process is included. Typ- ical examples found in the process section could include distillation columns or reactors.The process area is a complex collection of equipment that works together to produce products that will be sent to the final section. Flow Diagrams 255 MASTER ➁ Furnace Feed Tank Bottoms Tank Boiler Cooling Tower Reactors Product Tank 2 Product Tank 1 Vacuum Pump Column Drum Figure 12.2 Process Flow Diagram (PFD) 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 255
- 6. Process and Instrument Drawings A P&ID is a complex representation of the various units found in a plant (Figure 12.3). It is used by people in a variety of crafts. The primary users of the document after plant startup are process technicians and instrument and electrical, mechanical, safety, and engineering personnel. In order to read a P&ID, the technician needs an understanding of the equipment, instrumentation, and technology.The next step in using a P&ID is to memorize your plant’s process symbol list. This information can be found on the process legend. Process and instrument drawings have a va- riety of elements, including flow diagrams, equipment locations, elevation plans, electrical layouts, loop diagrams, title blocks and legends, and foun- dation drawings. The entire P&ID provides a three-dimensional look at the various operating units in a plant. Process Legend The process legend (Figure 12.4) provides the information needed to inter- pret and read the P&ID. Process legends are found at the front of the P&ID. The legend includes information about piping, instrument and equipment Chapter 12 ● Process Diagrams 256 MASTER ➁ F-105 Tk-10 Tk-16 B-105 CT-105 Rx-105 C-105 FCV I/P TT TC I/P PT PC PCV I/P LT LC I/P I/P LT LC TE TT TC I/P P-10 P-11 Rx-106 P-12 V-1 D-105 Tk-12 Tk-14 P-13 P-14 V-2 V-3 V-4 V-5 V-6 EX-105 V-7 P-15 FT FC Figure 12.3 Process and Instrument Diagram (P&ID) 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 256
- 7. Process and Instrument Drawings 257 MASTER ➁ Globe Valve Gate Valve Three-Way Valve Bleeder Valves Manual Operated Valve Gauge Orifice SAFETY (Gases) Ball Solenoid Valve CLOSED S Rotameter Four-Way Angle Plug Diaphragm Butterfly Check Valve Relief Valve Pneumatic Pneumatic Pinch Valve Stop Check Knife Valve INDUCED DRAFT Crossflow NATURAL DRAFT Counterflow FURNACE BOILER Vacuum Pump Centrifugal Drum Gear Pump Positive Displacement Dome Roof Tank Sphere Rotary Screw Compressor Progressive Cavity Screw Pump Reciprocating Pump Sump Pump Horizontal Vertical Internal Floating Roof Tank Cone Roof Tank Plate and Frame Heat Exchanger Air Cooled Exchanger (Louvers Optional) Double-Pipe Heat Exchanger C C Spiral Heat Exchanger Condenser Heater Single Pass Chimney Two Pass Draw Off Generic Tray Demister Spray Nozzle Packed Section Manway Vortex Breaker VALVE SYMBOLS EQUIPMENT SYMBOLS Minor Process Pneumatic Hydraulic Capillary Tubing Electromagnetic, Sonic Optical, Nuclear X X X X L L L Major Process Future Equipment Connecting Line Non-Connecting Line Non-Connecting Line Jacketed or Double Containment Mechanical Link Software or Data Link • • • • Electric Flow Indicator Flow Transmitter Flow Recorder Pressure Indicator Pressure Transmitter FI FT FR PI PT Temp. Indicator Temp. Transmitter Temp. Recorder Level Indicator Level Transmitter Level Controller TI TT TR LI LT LC LR Level Recorder TC Temp. Controller PR Pressure Recorder Pressure Controller PC 65 55 55 65 65 55 Flow Controller FC PIC PRC LA 105 40 25 I P Transducer Pressure Indicating Controller Pressure Recording Controller Level Alarm FE Flow Element TE Temperature Element LG Level Gauge AT Analyzer Transmitter APPROVED GENERAL LEGEND DRAWING NUMBER REVISION 1 P C E DATE 10-6-99 PAGE 1 OF 30 OO6543 DISTILLATION UNIT LINE SYMBOLS EQUIPMENT CONT. INSTRUMENT SYMBOLS PREFIXES ABBREVIATIONS CW- cooling water MU- makeup FW- feed water SE- sewer RX- reactor UT- utilities CA- chemical addition IA- instrument air D- drum C- column CT- cooling tower TK-tank F- furnace EX- exchanger P- pump V- valve Figure 12.4 Process Legend 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 257
- 8. symbols, abbreviations, unit name, drawing number, revision number, approvals, and company prefixes. Because symbol and diagram standard- ization is not complete, many companies use their own symbols in unit drawings. Unique and unusual equipment will also require a modified sym- bols file. Foundation Drawing The construction crew pouring the footers, beams, and foundation uses foundation drawings (Figure 12.5). Concrete and steel specifications are designed to support equipment, integrate underground piping, and provide support for exterior and interior walls. Process technicians do not typically use foundation drawings, but these drawings are useful when questions arise about piping that disappears under the ground and when new equip- ment is being added. Elevation Drawing Elevation drawings (Figure 12.6) show the location of process equipment in relation to existing structures and ground level. In a multistory structure, the elevation drawing provides the technician with information about Chapter 12 ● Process Diagrams 258 MASTER ➁ N W E S 64' 0" 28' 0" 28' 0" 6' 0" 8' 0" 10' 0" 6-8-10 Method 2' x 64' x 18" Load-Bearing Beam 18" 4" 12" Estimating Materials: cu. yds. = width x length x thickness 27 Remesh Remesh Over Plastic Remesh Rebar in All Beams 32' 0" 90 Figure 12.5 Foundation 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 258
- 9. equipment location.This information is important for making rounds, check- ing equipment, developing checklists, catching samples, and performing startups and shutdowns. Electrical Drawing Electrical drawings (Figure 12.7) include symbols and diagrams that de- pict an electrical system. Electrical drawings show unit electricians where power transmission lines run and places where power is stepped down or up for operational purposes. A process technician typically traces power to the unit from a motor control center (MCC). The primary components of an electrical system are the MCC, motors, transformers, breakers, fuses, switchgears, starters, and switches. Specific safety rules are attached to the operation of electrical systems. The primary safety system is the isolation of hazardous energy “lock-out, tag-out.” Process technicians are required to have training in this area. Figure 12.7 shows the basic symbols and flow path associated with an electrical drawing. Electrical lines are typically run in cable trays to switches, motors, ammeters, substations, and control rooms. A transformer is a device used by industry to convert high voltage to low voltage. The electric department always handles problems with transform- ers. Electric breakers are designed to interrupt current flow if design condi- tions are exceeded. Breakers are not switches and should not be turned on Process and Instrument Drawings 259 MASTER ➁ EL 16' 0" EL28' 0" EL-40' 0" TK-105 RX-105 TK-200 TK-300 RX-106 RX-300 C-300 D-56 Figure 12.6 Elevation Drawing 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 259
- 10. Chapter 12 ● Process Diagrams 260 MASTER ➁ V Voltmeter: measures voltage Vs Voltmeter Switch 27 Power Transformer: reduces high voltage Potential Transforming Symbol Under Voltage Relay M Motor MCC Motor Control Center Switch Fuse Circuit Breaker: a protective device that interrupts current flow through an electric circuit A As 50 51 Ammeter: measures electric current Ammeter switch Transformer Overcurrent Relay (Instantaneous) Transformer Overcurrent Relay (Time delay) Motor Circuit Contacts Current Transformer: reduces high voltage to instrumentation. BOILER Steam Turbine Generator 69,000 Volts 69 KV 13,200 V 13, 800 V 2,300 V 13.2 KV 13.8 KV 2.3 KV On Off Motor 2.3 KV or 480 Volts 51 MAIN TRANSFORMER As A 27 V Vs MCC #1 480V BUS MAIN POWER DISTRIBUTION ELECTRIC POWER PLANT M M Motor Starter Motor Starter Figure 12.7 Electrical Drawing 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 260
- 11. or off. If a tripping problem occurs, the technician should call for an electri- cian. Fuses are devices designed to protect equipment from excess cur- rent. A thin strip of metal will melt if design specifications are exceeded. During operational rounds, technicians check the ammeters inside the MCC for current flow to their electrical systems. Voltmeters, electrical devices used to monitor voltage in an electrical system, are also checked during routine rounds. Equipment Location Drawing Equipment location drawings (plot plans) show the exact location of equipment in relation to the plant’s physical boundaries (Figure 12.8). One of the most difficult concepts to explain to a new process technician is the scope and size of modern chemical processing. Most chemical plants and refineries closely resemble small cities; they have well-defined blocks and areas connected by a highway of piping and equipment. Equipment loca- tion drawings provide information about the neighborhood. Loop Diagrams A loop diagram traces all instrument connections between the field instru- ment and the control room panel. This includes instrument air lines, wiring connections at field junction boxes, and control room panels and front connections. Electrical One-Line Diagrams Like the piping in process systems, the wiring in a unit follows a path. Electri- cal diagrams show a flow path for distributing power throughout the unit and Process and Instrument Drawings 261 MASTER ➁ TK-100 TK-100 P-100 P-200 P-300 P-400 D-200 P-500A EX-200 EX-202 TK-1 TK-2 TK-3 TK-4 TK-1 TK-2 TK-3 TK-4 P-201 20' 0" 10' 0" 20' 0" 18' 0" 8' 0" 20' 0" 8' 0" 6' 0" 18' 0" 8' 0" 16' 0" 20' 0" C-200 C-200 TK-200 TK-200 TK-400 TK-400 TK-300 TK-300 Figure 12.8 Equipment Location 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 261
- 12. to all electrical equipment. These diagrams show the different voltage levels in the unit, electrical equipment such as transformers, circuit breakers, fuses, and motors and horsepower required. It also includes start/stop switches, emergency circuits, and motor control centers. Process technicians can use these diagrams to trace a system from the power source to the load. Review of Basic and Specialized Symbols Piping and Valves Each plant will have a standardized file for their piping symbols. Process technicians should carefully review the piping symbols for major and minor flows; electric, pneumatic, capillary, and hydraulic elements; and future equipment (Figure 12.9). The major flow path through a unit illustrates the Chapter 12 ● Process Diagrams 262 MASTER ➁ Y-type Strainer Duplex Strainer Basket Strainer D Detonation Arrestor F Flame Arrestor T Steam Trap S In-Line Silencer DS Desuperheater Ejector / Eductor Exhaust Head S Vent Silencer RS Removable Spool Flexible Hose Expansion Joint XXX Breather Vent Cover In-Line Mixer Diverter Valve Rotary Valve Pulsation Dampener Flange Minor Process Pneumatic Hydraulic Capillary Tubing Electromagnetic, Sonic Optical, Nuclear X X X X L L L Major Process Future Equipment Connecting Line Non-Connecting Line Non-Connecting Line Jacketed or Double Containment Mechanical Link Software or Data Link • • • • Electric Figure 12.9 Piping Symbols 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 262
- 13. critical areas a new technician should concentrate on. A variety of other symbols are included on the piping. These include valves (Figure 12.10), strainers, filters, flanges, spool pieces, insulation, piping size, pressure rat- ing, material codes, and steam traps. Pumps and Tanks Pumps and tanks come in a variety of designs and shapes. Common pump and tank symbols are shown on Figure 12.11. Compressors, Steam Turbines, and Motors Because compressors and pumps share a common set of operating prin- ciples and are classified as dynamic or positive displacement, the sym- bols for compressors may closely resemble those for pumps (compare Review of Basic and Specialized Symbols 263 MASTER ➁ Globe Valve Gate Valve Three-Way Valve Bleeder Valves Pneumatic Operated Manual Operated Valve Gauge Orifice SAFETY (Gases) Butterfly Ball Solenoid Valve CLOSED S Rotameter Four-Way Needle Angle Plug Diaphragm Butterfly Butterfly Check Valve Check Valve Relief Valve M Pneumatic Motor Hydraulic M H M H M Ball H M Pneumatic Motor Hydraulic Motor Motor or Hydraulic Pneumatic Motor M GATE VALVES GLOBE VALVES BALL VALVES BUTTERFLY VALVES DIAPHRAGM VALVES CHECK VALVES PLUG VALVES Motor or Hydraulic Motor or Hydraulic Plug Pinch Valve Stop Check Knife Valve RELIEF (Liquids) Figure 12.10 Valves 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 263
- 14. Figures 12.11 and 12.12). In most cases, the compressor symbol is slightly larger than the pump symbol. In the multistage, centrifugal compressors, the narrowing of the symbol from left to right denotes compression of the gas before it is released. This is in sharp contrast to the steam turbine symbol, which illustrates the opposite ef- fect as the steam expands while passing over the rotor. Modern P&IDs show the motor symbol connected to the driven equipment. This equipment may be a pump, compressor, mixer, or generator. Figure 12.12 illustrates the standardized symbols for compressors, steam turbines, and motors. Heat Exchangers and Cooling Towers Heat exchangers and cooling towers are two types of industrial equipment that share a unique relationship. A heat exchanger is a device used to Chapter 12 ● Process Diagrams 264 MASTER ➁ Vacuum Pump CENTRIFUGAL PUMPS Bin Tank Drum Gear Pump Vertical Screw Pump POSITIVE DISPLACEMENT PUMPS Positive Displacement Dome Roof Tank Open Top Tank Tank Sphere Onion Tank STORAGE SYMBOLS Progressive Cavity Positive Displacement Screw Pump Vertical Can Pump Reciprocating Pump Sump Pump Horizontal Vertical Vertical Internal Floating Roof Tank Cone Roof Tank Double Wall Tank External Floating Roof Figure 12.11 Pumps and Tanks 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 264
- 15. transfer heat energy between two process flows. The cooling tower per- forms a similar function, but cooling towers and heat exchangers use dif- ferent scientific principles to operate. Heat exchangers transfer heat energy through conductive and convective heat transfer, whereas cooling towers transfer heat energy to the outside air through the principle of evaporation. Figures 12.13 and 12.14 illustrate the standard symbols used for heat exchangers and cooling towers. The symbol for a heat exchanger clearly illustrates the flows through the device. It is important for a process technician to be able to recog- nize the shell inlet and outlet and the tube inlet and outlet flow paths. A heat exchanger with an arrow drawn through the body illustrates whether the tubeside flow is being used to heat or cool the shellside fluid. The downward direction indicates heating; the upward direction il- lustrates cooling. Review of Basic and Specialized Symbols 265 MASTER ➁ Figure 12.12 Compressors, Steam Turbines, and Motors STEAM TURBINE Doubleflow Turbine Rotary Compressor Reciprocating Compressor Rotory Compressor & Silencers CENTRIFUGAL COMPRESSORS Centrifugal Compressor Centrifugal Compressor (Turbine Driven) PD COMPRESSORS Rotary Screw Compressor Positive Displacement Blower Liquid Ring Vacuum Centrifugal Blower Centrifugal Compressor Reciprocating Compressor Motor MOTORS Turbine Driver Diesel Motor Agitator or Mixer Axial Compressor T 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 265
- 16. Chapter 12 ● Process Diagrams 266 MASTER ➁ Plate and Frame Heat Exchanger Air Cooled Exchanger (Louvers Optional) Double-Pipe Heat Exchanger C C Spiral Heat Exchanger Shell and Tube Heat Exchanger Single Pass Heat Exchanger U-Tube Heat Exchanger Hairpin Exchanger Condenser Heater Reboiler Figure 12.13 Heat Exchangers INDUCED DRAFT Crossflow FORCED DRAFT Counterflow HYPERBOLIC Chimney Tower NATURAL DRAFT Counterflow Figure 12.14 Cooling Towers 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 266
- 17. The symbol for a cooling tower is designed to resemble the actual device in the process unit. Cooled product flows out of the bottom of the tower and to the processing units. Hot water returns to a point located above the fill. The symbol will not show all of the various components of the cooling tower system, but it will provide a technician with a good foundation in cooling tower operation and enough information to clearly see the process. Furnaces and Boilers The standard symbols file for furnaces and boilers is shown in Fig- ure 12.15. If a proprietary process includes several types of equipment not typically found on a standard symbol file, the designer will draw the device as it visually appears in the unit. Distillation Columns Distillation columns come in two basic designs, plate and packed (Fig- ure 12.16). Flow arrangements vary from process to process. The sym- bols allow the technician to identify primary and secondary flow paths. Distillation is a process designed to separate the various components in a mixture by their boiling points. (See Chapter 15.) A distillation column is the central component of a much larger system. This system typically in- cludes all of the equipment symbols found in this chapter. Plate distillation columns include sieve trays, valve trays, and bubble-cap trays. Packed columns are filled with packing material, rings, saddles, sulzer, and rosette. Reactors Reactors (Figure 12.17) are stationary vessels and can be classified as batch, semibatch, or continuous. A reactor is designed to allow chemi- cals to mix together under specific conditions to make chemical bonds, break chemical bonds, or make and break chemical bonds to form new products. Review of Basic and Specialized Symbols 267 MASTER ➁ Furnace Boiler Figure 12.15 Furnace and Boiler 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 267
- 18. Sources of Information for Process Technicians Information used by process technicians comes from a variety of sources. Some of these sources are: • Operating training manuals • Process descriptions • Process control manuals • Equipment summaries • Safety, health, and environment regulations • Operating procedures • Startup and shutdown procedures Chapter 12 ● Process Diagrams 268 MASTER ➁ PLATE TOWER Bubble-cap, Sieve, Valve PACKED TOWER Saddle, Ring, Sulzer, Rosette Single Pass Chimney Two Pass Draw Off Generic Tray Demister Spray Nozzle Packed Section Manway Vortex Breaker Figure 12.16 Distillation Symbols 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 268
- 19. • Emergency procedures • Process diagrams • Technical data books • Detailed equipment vendor information Summary Process flow diagrams (PFDs) and process and instrument drawings (P&IDs) are used to outline or explain the complex flows, equipment, in- strumentation, electronics, elevations, and foundations that exist in a process unit. A PFD is a simple flow diagram that describes the primary flow path through a unit. A P&ID is a complex representation of the various units found in a plant. Standardized symbols and diagrams have been developed for most pieces of industrial equipment, process flows, and instrumentation. Summary 269 MASTER ➁ Hydrocracking Hydrodesulfurization Reformer Fluid Catalytic Cracking Fluid Coking Tubular Reactor Fluidized Reactor Mixing Reactor Alkylation Figure 12.17 Reactor Symbols 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 269
- 20. Chapter 12 ● Process Diagrams 270 MASTER ➁ Review Questions 1. Describe a process flow diagram and a process and instrument drawing. 2. Draw the symbols for a gate, globe, and automatic valve. 3. Draw the symbols for a centrifugal pump and positive displacement pump. 4. Draw the symbols for a blower and a reciprocating compressor. 5. Draw the symbols for a steam turbine and centrifugal compressor. 6. Draw the symbols for a heat exchanger and a cooling tower. 7. Draw the symbols for a packed distillation column and plate distillation column. 8. Draw the symbols for a furnace and a boiler. 9. Draw a simple process flow diagram using the symbols from questions 2–8. 10. What information is obtained from a loop diagram? 11. What information is available on electrical one-line diagrams? 12. What information is contained on a plot plan drawing? 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 270