Project Synopsis

Size a small number of relief valves at a railcar unloading facility to assist the client of an engineering firm.

Project Summary


Process Engineering Associates, LLC (PROCESS) was subcontracted by the client, an engineering and design firm, to size four (4) relief valves for the ultimate client, a diversified technology company, for a railcar unloading station.  PROCESS utilized its proprietary in-house relief device capacity computer program, with calculations based on the guidelines in American Petroleum Institute (API) Recommended Practices (RP) 520 and 521, to determine the pressure relief requirements for the railcar unloading station.

Two of the relief valves were for the steam coils on the railcars.  The overpressure scenario considered for these PSVs was a pressure control valve failing.  The third relief valve was for a flash steam recovery vessel.  A pool fire scenario and failed open steam trap were the overpressure scenarios evaluated for this PSV.  The final relief valve was for the condensate return pump, and the scenario evaluated was a pressure control valve failing.

PROCESS supplied the client with the relief valve sizing calculations as well as datasheets that could be used to obtain quotes from vendors for the relief valves.  Also, PROCESS utilized vendor-supplied literature to suggest specific relief devices.

Industry Type

  • Engineering / EPC
  • Chemical Railcar Unloading

Utilized Skills

  • Pressure relief valve (PRV) and pressure safety valve (PSV) sizing
  • Relief scenario identification
  • Relief device selection

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