1、Process Diagrams OBJECTIVES After studying this chapter, the student will be able to: R e view process diagram symbols. Describe the use of process diagrams and the information they contain. D raw a process ow diagram. D raw a process and instrument drawing. Describe the various process equipment re
2、lationships. 251 MASTER 30678_12_ch12_p251-270.qxd 06/09/2006 11:14 Page 251MASTER Key Terms Electrical drawingssymbols and diagrams that depict an electrical process. Elevation drawingsa graphical representation that shows the location of process equipment in relation to existing structures and gro
3、und level. Equipment location drawingsshow the exact oor plan for location of equipment in relation to the plans physical boundaries. Flow diagrama simplied sketch that uses symbols to identify instruments and vessels and to describe the primary ow path through a unit. Foundation drawingsconcrete, w
4、ire mesh, and steel specications that identify width, depth, and thickness of footings, support beams, and foundation. Legendsa document used to dene symbols, abbreviations, prexes, and specialized equipment. Process and instrument drawing (P also called piping and instrumentation drawing. Chapter 1
5、2 Process Diagrams 252 Types of Process Diagrams Process diagrams can be broken down into two major categories: process ow diagrams (PFDs) and process and instrument drawings (P others differ from plant to plant. Some standardization of process symbols and diagrams is taking place. The symbols used
6、in this chapter reect a wide variety of petrochemical and renery operations. Figure 12.2 is a PFD that shows the basic relationships and ow paths found in a process unit. It is easier to understand a simple ow diagram if it is broken down into sections: feed, preheating, the process, and the nal pro
7、ducts. 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 ow is gradually heated for processing. This section includes heat
8、 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 nal section.
9、 Flow Diagrams 255 MASTER 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 255Process and Instrument Drawings A P they have well-dened blocks and
10、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 eld instru- ment and the control room panel. This includes instrument air lines, wiring connectio
11、ns 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 ow path for distributing power throughout the unit and Process and Instrument Drawings 261 MAS
12、TER 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
