Petroleum Refining Design and Applications Handbook. A. Kayode Coker

GT - Gas Turbine MB - Motor for Blower MC - Motor for Compressor MF - Motor for Fan MP - Motor for Pump P - Pump PH - Process Heater or Furnace R - Reactor S - Separator St - Strainer ST - Steam Turbine Str - Steam trap SV - Safety Valve Tr - Trap V - Valve VRV - Vacuum Relief Valve

Item Code	Represents
C-1a	Three compressors of identical size operating in the same process service, connected in parallel.
C-1b
C-1c
C-2	Single compressor in different service (by fluid or compression ratio) from C-1’s above. S-1 First separator in a process
S-2	Second separator in a process
S-3a	Two identical separators connected in parallel, in the same process service.
S-3b

      Some equipment code systems number all items on first process flowsheet with 100 series, as C-101, C-102, P-106 to represent compressors number 101 and 102 in different services and pump 106 as the sixth pump on the sheet. The second sheet uses the 200 series, etc. This has some engineering convenience but is not always clear from the process view.

      To keep process continuity clear, it is usually best to number all like items sequentially throughout the process, with no concern for which flowsheet they appear on. Also, another popular numbering arrangement is to identify a system such as reaction, drying, separation, purification, incineration, vent, and cooling tower waters and number all like process items within that system for example:

Table 14.5 Typical identification for flowsheet process functions.

AS	- Air Supply
BD	- Blowdown
BF	- Blind Flange
CBD	- Continuous Blowdown
CD	- Closed Drain
CH-O	- Chained Operated
CSO	- Car Seal Open
CSC	- Car Seal Closed
DC	- Drain Connection
EBD	- Emerg. Blowdown Valve
ESD	- Emerg. Shutdown
FC	- Fail Closed
FO	- Fail Open
HC	- Hose Connection
IBD	- Intermittent Blowdown
LO	- Lock Open
ML	- Manual Loading
NC	- Normally Closed
NO	- Normally Open
OD	- Open Drain
P	- Personnel Protection
QO	- Quick Opening
SC	- Sample Protection
SO	- Steam Out
TSO	- Tight Shut Off
VB	- Vacuum Breaker

Reactor System, R:	Reactor is RD-1
	Reactor vent cooler is RE-1
	Reactor vent condenser is RE-2
	Reactor recycle pump is RP-1
	Level control valve is RLC-1
	Relief valve is RSV-1

      Then, establish the same concept for all other unit or block processing systems. This is often helpful for large projects, such as refinery or grass roots chemical processes. Valve identification codes are usually used in preference to placing each valve specification on the flowsheet. This latter method is feasible for small systems, and is most workable when a given manufacturer (not necessarily the same manufacturer for all valves) can be selected and his valve catalog figure number used on the flowsheet. For large jobs, or where many projects are in progress at one time, it is common practice to establish valve specifications for the various process and utility services (see Figures 14.21 and 14.22) by manufacturers’ catalog figure numbers. These are coded as V-11, V-12, V-13, etc., and such code numbers are used on the flowsheets whenever these valves are required (also see Figures 14.8 and