Page 24 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap01 Final Proof page 12 4.1.2007 6:12pm Compositor Name: SJoearun

1/12 PETROLEUM PRODUCTION ENGINEERING FUNDAMENTALS
from the process and to minimize the adverse effects of 3. Mechanical failure due to temperature change,
such releases if they occur. This can be achieved by the overpressure and underpressure, and external im-
following: pact force
C. Liquid overflow caused by
1. Preventing undesirable events 1. Increased input flow due to upstream flow-control
2. Shutting-in the process device failure
3. Recovering released fluids 2. Decreased output flow due to blockage in the liquid
4. Preventing ignition discharge
The modes of safety system operation include D. Gas blow-by caused by
1. Increased input flow due to upstream flow-control
1. Automatic monitoring by sensors device failure
2. Automatic protective action 2. Decreased output flow due to blockage in the gas
3. Emergency shutdown discharge
Protection concepts and safety analysis are based on un- E. Underpressure caused by
desirable events, which include 1. Outlet flow-control device (e.g., choke) failure
2. Inlet blockage
A. Overpressure caused by 3. Cooling of closed system
1. Increased input flow due to upstream flow-control F. Excess temperature caused by
device failure 1. Overfueling of burner
2. Decreased output flow due to blockage 2. External fire
3. Heating of closed system 3. Spark emission
B. Leak caused by
1. Corrosion Figure 1.17 presents some symbols used in safety system
2. Erosion design. Some API-recommended safety devices are shown
in Figs. 1.18 through 1.22.

Flow Safety Burner Safety Pressure Safety Pressure Safety
Valve Low High & Low Element

FSV
BSL PSHL PSE

Flow Safety Flow Safety
High
Low Pressure Safety Valve

FSH FSL
PSV
PSV

Level Safety Level Safety
High Low Temperature Temperature
Safety High Safety Low

LSH LSL TSH TSL

Flow Safety Level Safety
High & Low High & Low Temperature Temperature
Safety Safety Element
High & Low
FSHL LSHL TSE
TSHL

Figure 1.17 Safety device symbols.