Relief Systems · Advanced · 1 day

Two-Phase Relief and Runaway Reactions (DIERS)

Vent sizing for flashing, foaming and reactive systems using the DIERS methodology

Duration1 day
LevelAdvanced
FormatOn-site · virtual
CodeTR-C05
V-201 To flare Set 14.5 bargFire · blocked outlet
Course flyer

Two-Phase Relief and Runaway Reactions (DIERS) — one-page catalogue.

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Two-Phase Relief and Runaway Reactions (DIERS) — one-page course flyer
Click the flyer to open the printable PDF.
Request this courseDownload the Training Request Form, quote course code TR-C05, sign and e-mail it to sales@cerasus.ai — or use the consultation form below.
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At a glance

What you will be able to do.

Relief and process safety engineers in petrochemical, polymer and specialty-chemical plants; engineers responsible for reactor and batch relief design

Single-phase vapour sizing under-predicts the required area by a factor of several when the vessel swells and vents a two-phase mixture. The course explains when two-phase flow must be assumed, how to characterise a reactive system from calorimetry data, and how to size the vent with the DIERS methods: Omega, homogeneous equilibrium, Leung and the tempered/gassy/hybrid classification. A runaway reaction case study runs from calorimeter trace to vent area and effluent handling.

  • Judge when two-phase venting must be assumed: level swell, foaming, reactive and viscous systems
  • Interpret adiabatic calorimetry (ARC, VSP2) data for onset, adiabatic temperature rise and pressure rate
  • Classify systems as vapour, gassy or hybrid and choose the sizing basis accordingly
  • Size vents with the Omega method, HEM and the Leung equation for tempered systems
  • Handle flashing and non-flashing flow through valves, discs and inlet lines
  • Design effluent handling: catch tanks, quench and separation to avoid a second release
Course outline

Day by day

Morning

Why single-phase sizing fails: incidents and DIERS history · level swell and flow regimes · thermal runaway fundamentals · reading calorimetry data · vapour, gassy and hybrid system classification

Afternoon

Omega method and HEM · Leung and tempered-system sizing · gassy and hybrid systems · inlet line, disc and valve behaviour in two-phase flow · effluent handling and catch-tank design · runaway case study in CeraVent

Standards referenced
CCPS Guidelines for Pressure Relief and Effluent Handling Systems
DIERS Project Manual
API 520 Part I
API 521
ISO 4126-10
ASME BPVC Section VIII
Request a consultation

Tell us about the unit and the problem.

Send a short brief — plant, service of interest and what you need to achieve — and a Cerasus engineer will respond with a proposed scope and next steps.

Prefer email or phone? sales@cerasus.ai · +974 5506 2743