rel="nofollow" href="#ulink_ad078e31-d420-5222-903c-7900ebac0a1e">Figures 14.8, 14.9, 14.15a, and 14.15b.
Recently, intelligent P&IDs are being incorporated in plant operations, where in the past P&IDs were hard copy drawings that were computer aided design (CAD) products. The latest generation of intelligent P&IDs uses software that incorporates commercial databases, thus allowing ease of integration to other applications such as calculation packages, inclusion of “smart objects,” data sheet information, ease of use and additional features that surpass CAD deliverables of P&IDs. Novak [13] provides the advantages of incorporating intelligent P&IDs during engineering procurement construction (EPC) phases in terms of reduced capital expense by lowering project costs and improved engineering and design work flow and time to the market. Intelligent P&IDs software enhances database access by separate design teams worldwide for concurrent engineering; its uses during procurement and construction phases include integrating with material management programs, easy creation of subcontractor packages and tracking of as-built changes. Table 14.3 illustrates a number of uses of intelligent P&IDs by operations, resulting in significant return on investment (ROI).
Table 14.3 Uses of intelligent P&IDs by operations.
| Provides high integrity of P & ID data—no need to field verify for decision support | Integration with other operations supports software such as reliability solutions. Plant management (PM) or turnaround planning. |
| Provides fast access to accurate, current data to aid troubleshooting | Aids in planning and executing emergency or maintenance procedures. |
| Allows change filtering and recording of updates to meet regulatory compliance | HAZOP analysis for safety checks and audit trails for OSHA, EPA and other compliance initiatives. |
| Shortened commissioning times | Risk-based inspection and critical system documentation. |
| Data filtration helps evaluate operational costs related to design scenarios | Production adjustments/reanalysis of process for feedstock variances. |
| Quicker startups | Allows multiple locations to view P & ID data. |
Source: Novak [13] By permission from Hydrocarbon Processing.
14.9 Flowsheet Symbols
To reduce detailed written descriptions on flowsheets, it is usual practice to develop or adopt a set of symbols and codes, which suit the purpose. Flowsheet symbol standardization has been developed by various professional and technical organizations for their particular fields. The American National Standard Institute (ANSI) has also adopted most of these symbols. The following symbols references are related and useful for many chemical and mechanical processes:
1 1. American National Standard Institute (ANSI) (www.ansi.org)
2 2. American Institute of Chemical Engineers (AIChE) (www.aiche.org)(a) Letter Symbols for Chemical Engineering, ANSI Y10.12
3 3. American Society of Mechanical Engineers (ASME) (www.asme.org)(a) Graphic Symbols for Plumbing, ANSI and ASA Y32.4(b) Graphic Symbols for Railroads Maps and Profiles, ANSI or ASA Y32.7(c) Graphic Symbols for Fluid Power Diagrams, ANSI or ASA Y32.10(d) Graphic Symbols for Process Flow, ANSI or ASA Y32.11(e) Graphic Symbols for Mechanical and Acoustical Elements as Used in Schematic Diagrams, ANSI or ASA Y32.18(f) Graphic Symbols for Pipe Fittings, Valves and Piping, ANSI or ASA Z32.2.3(g) Graphic Symbols for Heating, Ventilating and Air Conditioning, ANSI or ASA Z32.2.4(h) Graphic Symbols for Heat–Power Apparatus, ANSI or ASA Z32.2.6
4 4. Instrument Society of America (ISA) (www.isa.org)(a) Instrumentation Symbols and Identification, ISA-S5.1.
5 5. American Petroleum Institute (API) (www.api.org)
6 6. British Standards Institute (www.bsi-global.com)
Other symbols are established for specialized purposes. The physical equipment symbols established in some of these standards are often not as descriptive as those in the chemical, petrochemical, and petroleum industry is accustomed to using. The bare symbolic outlines given in some of the standards do not adequately illustrate the detail needed to make them useful. Accordingly, many process engineers develop additional detail to include on flowsheets, such as Figures 14.16a–e and 14.17a–c, which enhance the detail in many of these standards. Various types of processing suggest unique, yet understandable symbols, which do not fit the generalized forms.
Many symbols are pictorial which is helpful in representing process as well as control and mechanical operations. In general, experience indicates that the better the representation including relative location of connections, key controls and even utility connections, and service systems, the more useful will be the flowsheets for detailed project engineering and plant design.
To aid in readability by plant management as well as engineering and operating personnel, it is important that a set of symbols be developed as somewhat standard for a particular plant or company. Of course, these can be improved and modified with time and as needed, but with the basic forms and letters established, the sheets can be quite valuable. Many companies consider their flowsheets quite confidential since they contain the majority of key processing information, even if in summary form.
Figure 14.16 (a) Process variables; (b) Pumps and solids [9]. (c) Storage and equipment; (d) Flow and instruments [9]. (e) Filters, evaporators, and driers [9].
14.10 Line Symbols and Designations
The two types of lines on a flowsheet are (1) those representing outlines and details of equipment, instruments, and so on, and (2) those representing pipe carrying process or utility liquids, solids, or vapors and electrical or instrument connections. The latter must be distinguished among themselves
