FAQ Pressure Relief Valve Sizing Utilizing Aspen TECH Software PDF

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FAQ pressure Relief valve sizing utilizing Aspen Tech Software. Lecture....

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software Frequently Asked Questions Katherine Hird, Product Marketing, Aspen Technology, Inc. Anum Qassam, Product Management, Aspen Technology, Inc.

© 2015 Aspen Technology, Inc. AspenTech®, aspenONE®, the Aspen leaf logo, the aspenONE logo, and OPTIMIZE are trademarks of Aspen Technology, Inc. All rights reserved.11-7332-0515

FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

Table of Contents Introduction ............................................................................................................................................................................................................ 1 Frequently Asked Questions: High-level Functionality................................................................................................................................ 1 Frequently Asked Questions: How to Utilize High-level Functionalities ................................................................................................ 3 Frequently Asked Questions: Inlet/Outlet Line Sizing ............................................................................................................................... 7 Frequently Asked Questions: API Standards/Compliance ........................................................................................................................ 8 Frequently Asked Questions: Calculation Methodologies ........................................................................................................................ 9 Frequently Asked Questions: Fire & Latent Heat ....................................................................................................................................... 11 Frequently Asked Questions: Documentation ............................................................................................................................................12 Conclusion ............................................................................................................................................................................................................13 Additional Resources .........................................................................................................................................................................................13

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

Introduction Process safety, specifically overpressure analysis, is of the highest concern to every process across all industries, as accurate pressure relief sizing reduces the potential risk of damages to personnel, equipment, and production schedule. Pressure relief analysis is not a trivial task, as workflows can consist of gathering pertinent data, identifying distinct systems of a process, and analyzing all overpressure scenarios for each system. Each scenario requires calculating pressure relief loads and pressure relief device orifice sizes, then determining the discharge of the relieving fluid, often through a flare system. All of these steps, in combination with strict regulations requiring compliance and extensive documentation reporting, provide a cumbersome and inefficient pressure relief analysis workflow. AspenTech’s Process Safety Solution helps to streamline this workflow from sizing pressure relief devices through the design or rating of flare systems all within one software suite, requiring no manual data transfer. Introduced in Aspen HYSYS® V8.3 and Aspen Plus® V8.6, the Safety Analysis Environment within both AspenTech Simulators provides tools to add and rigorously size pressure relief devices. In combination with the simulator and Aspen Flare System Analyzer, the Safety Analysis Environment completes the AspenTech Process Safety Solution. Since introduction of the Safety Analysis Environment and through subsequent releases, a variety of enhancements have been made to this relief sizing tool to further enhance the efficiency and accuracy of pressure relief analysis work. The intent of this document is to answer common questions regarding the features, functionalities, and resources available for the relief sizing tools provided through the Safety Analysis Environment. Should any additional questions arise while referencing this document, do not hesitate to utilize the variety of materials hyperlinked throughout this text, contact AspenTech’s customer support staff at [email protected], or visit the customer support website at http://support.aspentech.com/.

Frequently Asked Questions: High-level Functionality 1.

In which versions are the Relief Sizing tools available?

The Relief Sizing functionality is available in Aspen HYSYS version 8.3 and greater. The functionality is also available in Aspen Plus version 8.6 and greater.

2. What differentiates the Relief Sizing functionality between versions? In Aspen HYSYS V8.3, you can determine the required relief load, calculate PSV orifice areas for single and two-phase flow, determine the inlet and outlet pressure losses, and generate documentation pertaining to the analysis. Note that an update to Aspen HYSYS V8.3 is available on the AspenTech Support Website. Please ensure that you have the latest update to Aspen HYSYS V8.3. In Aspen HYSYS V8.4, you have all the features of V8.3. You can also export the analysis results to Flare System Analyzer V8.4. Note that an update to Aspen HYSYS V8.4 is available through the AspenTech Support Website. Please ensure that you have the latest update to Aspen HYSYS V8.4. In Aspen HYSYS V8.6*, you have all the features of V8.4. You can also analyze low pressure storage tank protection per API 2000, rigorously calculate the external fire relief load, split required relief loads across multiple devices, and analyze rupture disk adequacy. Note that an update to Aspen HYSYS V8.6 is available through the AspenTech Support Website. Please ensure that you have the latest update to Aspen HYSYS V8.6.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

In Aspen HYSYS V8.8*, you have all the features of V8.6. In V8.8 the new relief load calculation enhancements for heat exchanger tube rupture, control valve failure, and fire emergency scenarios further utilize the integration with the simulators to generate more automated and rigorous calculations. * The Relief Sizing functionality was also introduced to Aspen Plus V8.6. Aspen Plus V8.6 and greater has exactly the same features as Aspen HYSYS V8.6 and greater.

3. Are there follow-up instructional materials available? We have made instructional material available on aspenONE® Exchange, available from within the software, as well as through the AspenTech Support Website.

For material on Relief Sizing in V8.3 and V8.4: Getting started guide: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=138111 Computer-based training: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=137943

For material on Relief Sizing in V8.6 and greater: Getting Started Guide: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=140063 Computer-Based training: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=137943 Multivalve Analysis: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=140065 New Fire Calculation Algorithm: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=1400654 Low Pressure Storage Tanks: http://support.aspentech.com/webteamcgi/solutiondisplay_view.cgi?key=1400654

4. Is there a complete course available through AspenTech? Yes, we have a newly-created course available through our training group:

Pressure Relief Analysis Using Aspen HYSYS This new course has been designed to teach you how to define overpressure systems using Aspen HYSYS in accordance with API 520, 521, and 2000, and how to design single or multiple relief valves for all applicable scenarios in an overpressure system. You can sign up for this course through the AspenTech Training Center. A similar course for Aspen Plus customers is in progress.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

5. Does the Relief Sizing functionality account for vacuum relief? How so and in what version? Vacuum relief is currently determined only for low pressure storage tanks as part of the implemented API 2000 inbreathing calculations. This functionality is available in Aspen HYSYS version 8.6 and greater. It is also available in Aspen Plus version 8.6 and greater.

6. Does Aspen HYSYS include a feature for blowdown valve sizing in high pressure separators? The Aspen HYSYS Dynamic Depressuring Utility is a time-tested and validated utility that we recommend for the sizing of blowdown valves in high pressure separators.

7. Does the Relief Sizing tool use Aspen Plus or Aspen HYSYS Dynamics? What is the link between the two? The Relief Sizing functionality is primarily intended to determine the required orifice area for relief devices per API 520 and to provide a mechanism to document the relief analysis. We encourage you to use Aspen Plus and Aspen HYSYS Dynamics to more rigorously determine the required relief loads for more complex scenarios. You can then use the results of that analysis within the Safety Analysis environment.

Frequently Asked Questions: How to Utilize High-level Functionalities 8. Can we import other simulator files (Pro-II) into Aspen Flare System Analyzer? You’ll need to contact other vendors to get a complete answer. Aspen Flare System Analyzer can import data from a universal (.xml) format which the separate vendors have to provide. In general, our goal is to create a highly functional integrated environment within the products that we offer, providing you with the most efficient pressure relief workflow.

9. Can relief information be imported into another program (i.e. Siemens PPM)? No, the format of the Siemens database is completely different from the AspenTech database.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

10. Can ARC data be input to estimate relief sizing for runaway reactions? What is the recommended methodology for handling scenarios with reactions? To analyze runaway reactions, we recommend the use of the Aspen Plus PRD Rating Utility (PRES-RELIEF), which provides the maximum relief flow required during a runaway reaction, as well as the composition at the peak required flow rate. You can input ARC data directly into Aspen Plus, and then this data can be utilized in the Aspen Plus PRD Rating Utility. Once you’ve determined the composition and peak flow rate, you must then create a stream in the simulation environment. You can then use that stream data in the Relief Sizing tool. You can access the PRD Rating Utility on the Home tab of the Ribbon of Aspen Plus V8.6:

11. How can I enter equipment dimensions for calculating wetted surface areas? In the External Fire scenario, there is a table to enter dimensions for Horizontal, Vertical, and Spherical vessels. To account for any other specific geometry, you must manually specify the wetted area or include an additional area factor in your calculation. Note that in Aspen HYSYS V8.3, V8.4, and V8.6 and in Aspen Plus V8.6, vertical and horizontal vessels were assumed to have 2:1 Ellipsoidal Heads. Beginning in Aspen HYSYS and Aspen Plus V8.8, you can now select the head type (Hemispherical, Ellipsoidal, or Flat).

12. Does the rupture disk feature analyze hydraulic shock/water hammer? Aspen HYSYS Hydraulics in dynamics mode can analyze the momentum of a hydraulic system to observe pressure waves, but there are no specific tools or utilities to model hydraulic shock or water hammer.

13. How do you differentiate (calculation-wise) between different PSV types? In the Safety Analysis Environment, you can select between a Conventional, Balanced Bellows, and Pilot-Operated relief valve. Calculation-wise, the difference between the valves is the limit for the Maximum Allowable Backpressure (MABP). You can adjust the default values for the MABP in the Default Valve Settings dialog box.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

14. Is database information necessary before starting PSV calculations? We use a runtime Access Database, so you don’t need to set one up. Some basic information is required before beginning your analysis. The process conditions for normal operating conditions, an idea of the pressure profile in the system, and how that profile reacts to different scenarios, is the level of information required before beginning the analysis of PSVs.

15. Can I specify vendor-specific factors for the PSVs? Yes, you can specify vendor-specific orifice areas, the vendor-specific Kb, and the vendor-specific Kd. The vendor-specific orifice area can be specified in the Custom Orifices dialog box, as shown below.

The discharge coefficient Kd is scenario-specific, and can be specified in the Scenario Setup form, as shown below.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

The backpressure coefficient Kb is scenario-specific, and it can also be specified in the Scenario Setup form, as shown below.

16. Can I complete calculations in EN/SI units, and is this functionality version-specific? You can complete all calculations in either EN or SI units beginning with Aspen HYSYS V8.3 and Aspen Plus V8.6. Reports generated in HYSYS V8.3 are only available in SI units. In Aspen HYSYS V8.4, reports generated from the Documentation Builder are available in both SI and EN units. However, these reports can only be export to Excel in SI units. In Aspen HYSYS V8.6 (with the latest update installed) and greater, the Built-In HYSYS Reports and the reports from the Documentation Builder are both available in EN and SI units. The reports can be accessed from the Reports tab of the main Ribbon:

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

Frequently Asked Questions: Inlet/Outlet Line Sizing 17. Is there a warning if 3% inlet line losses are exceeded? Yes, the software will warn the user when the inlet pressure drop exceeds the specified constraints. Additionally, you can customize the inlet line loss criteria in the Line Design Preferences Dialog box.

18. Will the software notify the user when the outlet line pressure loss exceeds 10%? Yes, as with the inlet line losses, the software will warn the user when the outlet pressure drop exceeds the specified constraints. You can specify the outlet pressure loss design criteria by clicking the Valve Defaults button in the Customize tab of the main Ribbon. You can also specify the inlet loss design criteria by clicking the Line Design Preferences button.

19. Is V8.4 considered correct when filtering inlet/outlet flange to verify API requirements?

Yes, V8.4 selects the inlet and outlet PSV flange based on the set pressure and design temperature of the relief device. The flange size is based on the lowest inlet and outlet rating available for that orifice at that temperature. For example, a “T” orifice at set pressure of 115 psiG and 350 F will have a 350 x 150 flange rating, whereas a “T” orifice at 35 psiG and 350 F will have a 150 x 150 flange rating.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

20. How can we calculate the Mach number and recommended a line size for the PSV outlet line? The exit velocity is calculated in the Line Sizing tab of the PSV analysis.

21. Can line sizing calculations be done for different scenarios? Yes, but in order to do this, you must select a scenario as the sizing case, and complete the line sizing analysis for that scenario. Then, select the next scenario of interest, and complete the line sizing for that scenario as well. Continue this process for each scenario of interest. Each line sizing calculation is independently stored and can be individually reported. No information is lost by switching the sizing case.

Frequently Asked Questions: API Standards/Compliance 22. Are all calculations API compliant for liquid, vapor, and two-phase? Yes, all calculations are API compliant liquid, vapor and two-phase flows.

23. How can I use the API 2000 7th edition Annex A for low pressure storage tank analysis in Aspen Plus and Aspen HYSYS V8.6? Please ensure that you have the latest updates installed for Aspen Plus and Aspen HYSYS V8.6. With the latest updates installed, you will see a dropdown box in the Normal Venting tab of the storage tank form which allows you to select the API 2000 version of interest.

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FAQ: Pressure Relief Valve Sizing Utilizing AspenTech Software

24. Are the scenarios specific to API standards or are they usable for application in Europe or other regions? All defaults in the Safety Analysis environment are currently based on the API standards. However, the user can adjust all parameters to customize their analysis as needed to accommodate European (or other global) standards.

25. What curves do you use for backpressure correction factor (Kb)? Figure D-2 in the 7th Edition of API 520 is used to calculate the BP correction factor. The user can manually input the backpressure correction factor by reading the value from the vendor-specific curve, if available.

Frequently Asked Questions: Calculation Methodologies 26. Do you have tools available to calculate scenario relief loads? Yes. In Aspen HYSYS V8.3 and V8.4, the Safety Analysis environment offers simple calculation tools to calculate the required relief load for thermal expansion, heat exchanger tube rupture, control valve failure, fan failure, reflux failure, and fire. Aspen HYSYS V8.6 and Aspen Plus V8.6 introduced more rigorous fire relief load calculation methodologies. In addition to the rigorous fire relief load calculations of Aspen Plus and Aspen HYSYS V8.6, Aspen Plus and Aspen HYSYS V8.8 introduced more rigorous control valve and tube rupture relief load calculation methodologies.

27. Can the backpressure be calculated? A preliminary back...