Determine Rapid Depressurization Safety Limits for Design and Rating

Course Id:  EHY250   |   Duration:  1.00 day(s)   |   CEUs Awarded:  0.7   |   Level:  Intermediate

Course Objective

Rapid depressurization of a vessel is a common method for limiting the consequences associated with a process emergency. During such depressurization, the temperature of the fluid can drop significantly. It is critical to accurately determine the rate of temperature drop during blowdown so that the proper construction materials can be selected. Would you be interested in learning how to use the BLOWDOWNTM technology that has been used in hundreds of studies in oil and gas and chemical companies to model depressurization? In this course you will learn the industrial importance of BLOWDOWN technology and how it is used to accurately determine temperature profiles during depressurization process, which is critical to the design and operation of every process plant. This technology can help you reduce capital cost, but more importantly, improve the safety of the plant.


  • Process engineers who need advanced skills for more complex modeling tasks
  • Current Aspen HYSYS users looking to build upon their knowledge of basic steady-state procedures


  • Clear guidance on fundamental topics
  • Industry workflows
  • Hands-on workshops
  • Experienced instructor-guided demonstrations
  • Q&A on student-specific problems

Class Schedule

Class Agenda

EHY250: Determine Rapid Depressurization Safety Limits for Design and Rating


  • Discuss the industrial importance of accurate depressurizing simulations. Identify key Aspen Technology products and features that aid in performing safety studies. Discuss the capabilities and features.

Getting Started with BLOWDOWN
  • Add a BLOWDOWN analysis to an existing Aspen HYSYS simulation. ¬†Define all inputs, run and review results. Edit component mappings. Model cold case and fire case scenarios. Perform both design and rating calculations.

Workshop 1. Perform Basic Sizing and Rating Analyses
  • Introduce to the BLOWDOWN Analysis Tool and learn how to use this tool for a designing & rating an orifice for pool fire depressurization scenario and cold case depressurization.
  • Task 1 - Rate a blowdown orifice for the fire case
  • Task 2 - Design a blowdown orifice for the fire case
  • Task 3 - Rate a blowdown orifice for the cold case
  • Overview of Proprietary Algorithms: ¬†Identify the need for proprietary algorithms in BLOWDOWN. Discuss how the algorithms handle inventory rebalancing, component mapping, and component consolidation.

Workshop 2. Component Mapping
  • Understand the process that Aspen HYSYS uses to map HYSYS components into BLOWDOWN components.
  • Task 1 - Troubleshoot a Failed Component Mapping
  • Task 2 - Manually Map the Failed Component

Aspen Technology, Inc. awards Continuing Education Units (CEUs) for training classes conducted by our organization. One CEU is granted for every 10 hours of class participation.