Monthly Archives for November 2012
Conventional Relief Valves Working Principle
The figure above shows a cross section of a conventional relief valve. Conventional relief valves can be used if the header back pressure is low. The conventional relief valves are commonly used on onshore facility where relief valves are fitted … Continue reading
Critical Flow
The critical flow which also referred to as sonic flow, choked flow, or Mach 1 is the limitation point of a compressible fluid flow through an orifice. The critical flow can occur on a relief valve orifice or a choke. … Continue reading
Back Pressure Effects on Relief Valves
The back pressure at production train can affect the relief valve’s capacity or the relief valve’s set pressure. The capacity of a relief valve is the maximum flow rate while the set pressure is the cranking pressure of the relief … Continue reading
Balanced Bellows Relief Valves
Balanced type relief valves consist of spring-loaded valves which contain a bellows arrangement to keep back-pressure from affecting the set point. The picture above shows a balanced bellows relief valve diagram. The bonnet is vented to atmosphere and a bellows … Continue reading
Heat Exchanger Types
The figure above shows different arrangements of the shells, tubes and baffles in heat exchangers according to TEMA standard classifications. The first letter of the standards designates the heat exchanger front end while the second letter designates the shell type … Continue reading
Separation Retention Time
An amount of time is needed to assure that the liquid and gas reach equilibrium at separator. The time is defined as “retention time” or the average time a molecule of liquid is retained in the vessel assuming plug flow. … Continue reading
Vessel and Piping Relief Requirements
A pressure vessel may fail because of more than one condition different scenarios. A low pressure separator vessel may be subject to blocked discharge, gas blowbyfrom the high pressure separator, and fire but only one of these failures is assumed … Continue reading