Relief Valve From Hysys

FAQ: Pressure Relief Rel ief Valve Sizing in i n Aspen As pen HYS H YSYS YS ® Frequently Asked Questions Nicholas Brownrigg, Product Marketing, Aspen Technology, Technology, Inc. Wilfried Mofor, Product Management, Aspen Technology, Inc.

© 2013 Aspen Technology, Inc. AspenTech®, aspenONE®, the Aspen leaf logo, the aspenONE logo, and OPTIMIZE are trademarks trademarks of Aspen Technology, Inc. All rights reserved. reserved. 11-4334-1013

FAQ: Pressure Relief Valve Sizing in Aspen HYSYS ®

Contents Introduction............................................................................................................................................................................................................1 Frequently Asked Questions – Aspen HYSYS..................................................................................... ..........................................................1 Frequently Asked Questions – Scenario Analysis and PSV Sizing .................................................................................... ......................2 Frequently Asked Questions – Line Sizing................................................................................. ....................................................................3 Frequently Asked Questions – Documentation Builder ........................................................................................... .................................4 Additional Resources..........................................................................................................................................................................................5

© 2013 Aspen Technology, Inc. AspenTech®, aspenONE®, the Aspen leaf logo, the aspenONE logo, and OPTIMIZE are trademarks of Aspen Technology, Inc. All rights reserved. 11-4334-1013

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Introduction When designing a chemical process and its equipment, safety is of substantial concern. All possible strategies should be considered to eliminate the risk of accident and injury when implementing a process design. One safety concern that occurs frequently in a plant is the over-pressurization of equipment or piping. In order to prevent dangerous bursts, explosions, and fires, pressure relief valves are designed and installed to bleed out excess liquid or vapor causing pressure build-up. Process conditions vary vastly at each location of a pressure relief valve. Because of this, and the strict regulation of safety equipment, completing a design of a pressure relief valve by hand can be a time consuming and laborious exercise. To solve this problem, Aspen HYSYS V8.3 has a pressure safety valve sizing feature, which uses data from a process simulation to help automate PSV calculations. Since its release in August 2013, Relief Valve Sizing in Aspen HYSYS has garnered much interest, including many questions surrounding the program’s capabilities. This document lists questions that were repeatedly submitted to AspenTech regarding the V8.3 Aspen HYSYS release and its PSV sizing functionality, along with the answers to the questions. The intent of this document is to give you insight when exploring the relief valve functionality feature in Aspen HYSYS V8.3. Should any other questions arise while reading this document, do not hesitate to contact AspenTech’s customer support staff at [email protected], or visit the customer support website at http://support.aspentech.com/ .

Frequently Asked Questions—Aspen HYSYS 1)

What version of Aspen HYSYS is needed to perform relief valve sizing?

Aspen HYSYS V8.3 is needed. Aspen HYSYS is upward compatible, meaning V8.3 can read all simulations performed in previous versions.

2) How do I get the latest version of HYSYS V8.3? I have Version 8.0 installed on my computer. Can I download it online or do I need to request a CD? If you are a current AspenTech customer, you can request a FREE upgrade to the new version at the following website: http://support.aspentech.com/

If you are a new AspenTech customer, you can order online at the following website: http://www.aspentech.com/products/order-now/

3) Is relief valve sizing part of HYSYS? Do I have to upgrade my HYSYS to get it or is it a separate program like Flarenet? PSV sizing is a feature in Aspen HYSYS V8.3. You will need to upgrade to this version to get the PSV sizing functionality.

4) How many tokens does this functionality require in addition to the HYSYS 14 tokens? No additional tokens are required. The functionality is included when Aspen HYSYS V8.3 is opened.


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5)

Is relief valve sizing functionality also available in Aspen Plus ®?

For the latest release, relief valve sizing is available in Aspen HYSYS V8.3 only. However, AspenTech has received many requests to build the functionality into Aspen Plus and recognizes the demand for the feature.

6) Can an existing simulation done with version V7.3 be opened in HYSYS V8.3 in order to use the PSV sizing tools? Yes, upward compatibility is a feature in Aspen HYSYS V8.3, allowing users to take their models from any older versions of HYSYS and open them in Aspen HYSYS V8.3 without any loss of data.

Frequently Asked Questions—Scenario Analysis and PSV Sizing 1)

Before sizing a relief valve, one must build a process simulation first, correct?

Yes, although the user could also use an unattached, single stream that’s specified with fluid flow properties if he/she does not want to create a whole process simulation.

2)

Where are the sizing basis equations taken from?

They are taken from API 520.

3)

Can this program be used to size for a supercritical fluid?

Yes, supercritical fluids can be handled by Aspen HYSYS V8.3.

4)

Can Aspen HYSYS V8.3 size for two-phase flow?

Yes, two-phase PSV sizing methods are available in Aspen HYSYS V8.3, including the omega and HEM methods.

5) Does the program have the ability to calculate relief loads or does the user need to manually input the relieving flow rates? HYSYS has calculation methods for some common pressure relief scenarios. The user can also simulate the relieving scenario and pull the data directly from the stream or manually insert the relieving flow.

6)

Which scenarios have methods built-in to HYSYS?

These scenarios include fire, exchanger tube rupture, control valve failure, liquid thermal expansion, fan failure, and reflux failure.

7)

Can PSV sizing be performed for dynamic simulations?

Yes, if the user sets up a dynamic simulation in Aspen HYSYS Dynamics, the results of the dynamic simulation can be used for PSV sizing in Aspen HYSYS V8.3.


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8) For fire scenario sizing, does HYSYS calculate the latent heat of the fluid for a multi-component mixture while using the PSV sizing tool or does the user have to input the latent heat? Aspen HYSYS V8.3 calculates the latent heat of the relieving fluid, even if the fluid is multi-phase or multi-componential. The analysis to find the appropriate latent heat is not automated.

9)

How can I select the most suitable scenario for the PSV sizing?

You can make a scenario the “sizing case” by selecting a check box next to the appropriate scenario in the “Valve Parameters” tab or in the “Scenario Setup” tab.

10) Does Aspen HYSYS V8.3 house a database/library for different PSV models, sizes, or vendor brands? Aspen HYSYS V8.3 has all API 526 standard orifice areas for the different valve types. Custom orifices can be created in the “Customize” tab when these API valves don’t match vendor specifications or user needs.

11) If I change my basis simulation, how long does it take for the system to update the relief sizings? This is automatically updated in seconds.

12) Can Multiple PSVs be selected for relief? No, only one valve can be added per stream. The workflow to size multiple PSVs currently involves returning to process simulation and splitting a stream using a splitter block with the correct split fractions. The valves can then be added to the split streams.

13) Is the information from Aspen HYSYS directly transferrable to Aspen Flare System Analyzer? In V8.4 or higher, relief valve information obtained in Aspen HYSYS can be imported into Aspen Flare System Analyzer for flare design.

Frequently Asked Questions – Line Sizing 1)

Does Aspen HYSYS V8.3 size inlet and outlet lines?

Yes, relief valve sizing in Aspen HYSYS V8.3 is fully capable of sizing inlet and outlet lines for both single and mixed-phase systems based on pressure drop and fluid velocity constraints.

2)

Is the equivalent length calculation based on the Crane manual?

Yes, it is.


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3)

Does Aspen HYSYS V8.3 calculate inlet and outlet delta P?

Yes, inlet and outlet line delta Ps can be viewed in the line sizing tab after completing line sizing.

4)

What criteria does Aspen HYSYS consider for inlet and outlet line pressure drop?

The line sizing criteria are user specified, but Aspen HYSYS defaults to the percentage of the set pressure for the specific valve type for the outlet line, and uses the 3% rule for the inlet line.

5) Can the criteria for inlet sizing be specified, i.e. instead of a 3% limit on pressure drop, a client agreed to 4%—can that be changed? Yes, you can change the pressure drop and fluid velocity constraints in the ribbon under the "Customize" tab. The defaults from Aspen HYSYS are just strong suggestions per best engineering practice.

6) How easy is it to calculate inlet/outlet equivalent lengths for piping configurations involving pipe/fittings of multiple sizes? These calculations are quite easy to perform. Use the “Calculate Equivalent Length” option and you can specify the number of pipe fittings present for the inlet and outlet lines. An equivalent length is automatically calculated by Aspen HYSYS V8.3.

Frequently Asked Questions – Documentation Builder 1) One of the most important aspects of PSV sizing is that the sizing calculation and input data can be checked. Does Aspen HYSYS V8.3 include a printout/input data summary that can be produced for checking by senior engineers? Yes, there are many forms in the Documentation Builder that summarize details and assumptions in the calculations performed.

2) What type of forms are available for customization in the Documentation Builder? Calculation summary sheets, mechanical data sheets, process data sheets, and relief load summary sheets.

3)

Is a separate Microsoft Access licence needed to use the Documentation Builder?

No, the Documentation Builder can be run so long as Aspen HYSYS V8.3 is installed.

4) Are detailed results available for all selected relief scenarios and not just the governing scenario? Yes, all cases sized for each specific valve will be displayed in the Documentation Builder, not just the sizing cases.


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5)

Are the reports and data sheets available in Excel format?

Yes, all report forms in the Documentation Builder can be exported to Excel using the “Export to Excel” option on the Documentation Builder start page.

6) Does the tool document the scenario narrative describing the progression of the scenario—especially for more complex systems? There is a PSV Documentation Study feature in the Documentation Builder allowing users to input and record all assumptions made for each scenario studied, revision history for the PSV study, and PID numbers, etc.

7)

How do we get the company logo in the report header?

In the Documentation Builder, under customize, you can add the image/logo of your company. See the example file in aspenONE ® Exchange for more information.

Additional Resources Public Website: http://www.aspentech.com/products/HYSYS-Relief-Valves/ http://www.aspentech.com/products/aspen-hysys.aspx

Online Training: http://www.aspentech.com/products/aspen-online-training

AspenTech YouTube Channel: http://www.youtube.com/user/aspentechnologyinc


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About AspenTech AspenTech is a leading supplier of software that optimizes process manufacturing—for energy, chemicals, engineering and construction, and other industries that manufacture and produce products from a chemical process. With integrated aspenONE ® solutions, process manufacturers can implement best practices for optimizing their engineering, manufacturing, and supply chain operations. As a result, AspenTech customers are better able to increase capacity, improve margins, reduce costs, and become more energy efficient. To see how the world’s leading process manufacturers rely on AspenTech to achieve their operational excellence goals, visit www.aspentech.com.

Worldwide Headquarters Aspen Technology, Inc. 200 Wheeler Road Burlington, MA 01803 United States phone: +1–781–221–6400 fax: +1–781–221–6410 [email protected]

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Relief Valve From Hysys

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