hotline+ - Aspen Technologyhtfs.aspentech.com/Newsletters/pdfs/apr2004.pdf · and FIHRTM 2.10, providing continuing improvements and developments to the ... supersedes the FOCP spreadsheets.

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No. 60 April 2004 news from AspenTech - heat exchanger design excellence through research

In this issue....

New software releases

TASC FIHR Aspen Teams

Exchanger modelling in flowsheets

Research progress

Optimize enhancement

Heat Exchange / Concept phase to economic analysis

Training

Current Products

To Contact Us

New software releases

AspenTech’s HTFS+® team is delighted to announce the release of TASCTM 5.10 and FIHRTM 2.10, providing continuing improvements and developments to the usability and the calculation engines of both programs.

The first thing users will notice in the User Interface is a new navigation tree to access the input forms as an alternative to the previous tabbed forms. The tree highlights essential data items and indicates when sufficient data have been entered to run the case. The new interface also performs active checking of many input items as they are entered and where possible shows the default values that the program uses. Colour coding of data fields in the input forms indicates both the source of an input item (entered or defaulted) and the existence of a warning or fatal error. Output forms are also organised in a similar tree browser.

TASC 5.10 In this latest version of TASC, we have taken the opportunity to make some changes to the organisation of the input forms and in particular to clarify user control of the information generated by the new tube count calculations and displayed in the Tube Layout diagram. The program output has been supplemented by the first version of a new Report Generator with a tree view allowing the user to select some sections of output and display text information, tables, graphs, and diagrams. The report view on the screen is like a print preview of the output. There is the capability to print directly or export the results to pdf, Word, or Excel files, or as XML.

Calculation Engine

There have been many developments to the Calculation Engine providing the user with:

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enhanced methods for post-dryout heat transfer calculations providing soundly-based physical modelling. A film boiling equation is typically applied when dryout occurs at low vapour mass fractions, and a method representing heat transfer to a dry gas with dispersed liquid droplets is applied at high vapour mass fractions when dryout occurs in the convective boiling regime. improved treatment of partial dryout due to phase stratification in horizontal shellside evaporators. enhancements in the flow-induced vibration analysis including:

a prediction of vibration amplitudes for turbulent buffeting and vortex shedding, allowance for a support plate under the inlet nozzle, provision for input of axial stress, an updated method for two-phase damping, improved natural frequency calculation for unequal end spaces, user-defined choice of pinned or rigid support at a blanking baffle.

Other developments in TASC 5.10 include:

TEMA checks on the bundle entrance ρv2 taking into account interactive changes made in the tube layout drawing an option to input a nucleate boiling curve for enhanced tube surfaces provision for input of the tube end cut for reflux condensers and modelling its effect on the flooding velocity specify shellside nozzles with domes, perforated impingement plates, and impingement rods. The impingement plate can be specified as round or square, and can be located within a dome.

FIHR 2.10 Improved output is one of the major changes made to FIHR our program for designers and optimisers of fired process heaters. With this version you will access complete lineprinter output and the full output with navigation capability, report generation and improved graphics. The output can be also exported in various formats including PDF format.

Calculation Engine

Multiple fuels and multiple oxidants: you can specify up to 4 fuels and 4 oxidants in FIHR. This development allows the engineer to model mixtures of gas and liquid fuels in a flexible way, including "waste gas" streams. This supersedes the FOCP spreadsheets. Steam injection to process fluid in firebox can be now modelled. FIHR requires the input of flowrate and pressure of the injected steam in addition to the temperature, if superheated, or vapour



mass quality if wet. FIHR will then perform the required calculations and output the steam injection point and state of steam prior to injection, tables of properties calculated for the mixed steam and process stream and details of heat inputs to the process stream prior to, at and after injection. Multi-celled cabin fireboxes can now be modelled. These are divided into cells (assumed to be identical) by a number of lines of tubes. The improved convection section geometry specification now allows for tube banks with horizontal gas flow and either vertical or horizontal tubes to be modelled.

Other new capabilities include:

the burners in the firebox can now be set to either top or bottom firing a rigorous shield bank radiation model is included percent oxygen in flue gases can be specified as an alternative to excess air non-standard rectangular and triangular tube layouts are now permitted in the tube banks details of the process fluid flow regime are calculated and output for each tube improved defaults.

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Comply with the new ASME requirements for tubesheets

Aspen Teams® 12.1 continues to improve on the optimization routines for the optimal mechanical design of shell-and-tube heat exchangers.

Of great interest to the design community is the application of the new UHX rules for the design of tubesheets. These rules are now mandatory and supersede the rules in the TEMA standards (Tubular Exchanger Manufacturers Association). Designers should be aware of the improved design procedure for the stress analysis of complex assemblies. The UHX rules analyze the membrane and bending stresses of tubesheets and adjacent cylinders (shell and channel), the longitudinal and compressive stresses of tubes/shell, the radial thermal stresses of tubesheets, the tubesheet loads caused by mating flanges and the tube-to-tubesheet joint loads. As different load/stresses control (exceed the allowable) Aspen Teams will change the design until it finds the optimum geometry that meets all constraints.



For a proper design, thermal data must be available to correctly calculate thermal gradients and expansion/contraction of components. It is essential to have access to such thermal data (for example, as provided by the seamless integration with Aspen Tasc+). Without accurate thermal data the heat exchanger may be overstressed in actual operation by experiencing excessive pressure and expansion/contraction beyond the design limits. When such thermal data is present, Aspen Teams will even determine if an expansion joint is needed to keep the designer out of trouble! The ultimate objective of Aspen Teams has always been to provide a code compliant, trouble-free heat exchanger design, at the lowest possible cost.

New process equipment installed must meet the ASME construction code in most jurisdictions. The ASME code is modified every year with a compliance dateline of 1 January of the following year. We are pleased to announce that Aspen Teams 12.1 fully complies with the ASME Section VIII Division 1 addenda of 2003 for the mechanical design and construction of pressure vessels.

Additional improvements to Aspen Teams have been provided in a service pack (solution ID 113226) available at our support website. The application of the service pack will update Aspen Teams to version 12.1.4.

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HTFS+ thermal-hydraulic exchanger modeling in Aspen Plus Flowsheets

The release of Aspen Plus® as part of the Aspen Engineering SuiteTM (AES) 12.1 Suite and of the HTFS TASC program (TASC 5.10), brings you the capability of linking an Aspen Plus simulation directly with the detailed rigorous heat exchanger calculations of TASC.

Aspen Plus has available several models for heat exchanger calculations. It has its own simple and detailed methods. The simple model uses the HeatX shortcut method to specify UA for the heat exchanger. Whilst limited, this does make it easy to get a simulation working very quickly. Detailed calculations require specification of actual exchanger geometry.



The real power of the simulator is its ability to integrate the rigorous modeling of heat exchangers from HTFS or B-JAC with all of the other unit operations on the flowsheet. This liberates the process engineer to optimize his overall process with much better assurance of fidelity to real operation. He can approach this in a carefully structured way from concepts using simple models to increased detail using the research-based modeling excellence of HTFS+.

The HeatX block in Aspen Plus allows switching between shortcut, detailed, Aspen HetranTM (shell and tube), Aspen AerotranTM (air coolers) and now the TASC shell and tube calculations.

So how do you use the link? What is the workflow?

Let us assume that you already have a simulation based on the shortcut HeatX model in Aspen Plus. To use TASC you must first switch to use the rigorous shell and tube model and specify the file you will use. (To use TASC you must select the .TAI file extension.) You may already have an existing exchanger defined in TASC. In this case simply browse to select the file (with a .TAI file extension). You are finished. The heat exchanger will now solve as part of the simulation, running the TASC calculation engine whenever it is required.

If you want to design the heat exchanger, based on the process conditions (and associated physical properties) then use the Aspen Plus interface to save a new TASC input file. This will contain no geometry but will have all relevant process and property data. You can open the file by launching TASC standalone (with no need to close Aspen Plus). You can now either specify the heat exchanger geometry directly in TASC or switch to design mode for TASC to determine an appropriate geometry.

All that remains is to save the file, close TASC, and use the updated file, which now contains a fully specified heat exchanger in the Aspen Plus simulation.

The Aspen Plus interface gives access to some of the key results for the heat exchanger such as pressure drops, calculated outlet conditions, overall heat transfer coefficients. If more detailed output is required then the TASC user interface gives access to the full range of information, including detailed tables, flow distribution and vibration calculations.



This article has given an overview of the basics. With Aspen Plus there is a powerful optimizer, which allows the simulator to manipulate many of the variables associated with the exchanger. Hence, many kinds of studies (parametric, minimized energy consumption, optimized flow) are possible but using rigorous calculations at the heart of the simulation. The current link to TASC calculations requires the use of the TASC user interface to enter data and view detailed outputs. As Aspen Tasc+ is developed, the integration with Aspen Plus will be enhanced so that all the data can be accessed directly without the need to use a separate user interface.

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Putting the "+" into Heat Transfer Research

We continue to make excellent progress on various fronts with our experimental and analytical research.

The HTFS Compact Heat Exchanger rig in Valencia is now up and running and producing new data in upflow and downflow configurations. Research report RS1146 New low mass flux data for boiling of n-Pentane in plate-fin passages presented at the HTFS+ Annual Meeting in Paris marks the beginning of the HTFS Compact Heat Exchanger rig going on-stream and producing exciting new results. The UMIST reboiler facility has benefited from multi-million pound refurbishment of the UMIST pilot plant. The thermosyphon reboiler and the two after condensers have been relocated in the refurbished pilot plant – now named The Morton Laboratory. In addition, a second liquid ring vacuum pump has been installed so that independent vacuum circuits are available for the process side of the reboiler and the shell side. The apparatus is now much more compact, with shorter pipe lengths from the disengagement vessel to the first condenser and to the second after condenser. Still much work remains to be done on recalibration of instruments and commissioning of new improved data logging system. It is expected that a new project on UMIST reboiler will start from October 2004.



The UMIST reboiler in its new location

Research projects at NEL are also progressing well and three research projects are benefiting from the exercise of relocation and refurbishment underway at NEL.

A new series of experiments with Boiling and Condensing rig were completed before the work on removal and relocation began. Work is also in progress on building an improved rig for studying shellside viscous flow. The Multi-Purpose Wind Tunnel is now in its new place, fully commissioned and testing has already started. The Viscous flow facility and Boiling and condensing rig will soon follow suite and resume productive operation in their respective new locations.

The progress that is being made on experimental research is matched by progress on analytical and modeling work. For example, research reports RS1144 Single phase pressure drop characteristics of plate fin surfaces and RS1145 Single phase heat transfer characteristics of plate fin surfaces describe improvements made to single phase performance correlations for plate-fin passages. Another report RS1136 CFD modelling of inline tube bundles with plain high fins shows that CFD can be used to support method development by providing insight on local flow behaviour which is difficult to achieve by experiment work.

Typical temperature contours form CFD analysis for air cooler tubes

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HiTran® Selection Software - HiTran®SP

A long established HTFS customer and collaborator, Cal Gavin, has released a product which extends the capability of your HTFS+ programs. Their HiTran® matrix elements, utilized in more that 5000 systems, have a long history in improving heat exchanger performance by increasing tubeside heat transfer coefficients.



Applications encompass single- and two-phase.

HiTran Matrix Element

Cal Gavin has announced that its selection program (HiTran® SP) is now available on limited release. This application can fully optimize air-cooled heat exchangers with HiTran matrix element inserts, utilizing a run-time interface with ACOL 6.30. HiTran SP can also calculate tubeside performance in any heat exchanger. A comprehensive version will be available in due course which will also offer optimization of enhanced shell and tube heat exchangers through similar interfacing with TASC 5.10.

If you would like to obtain further details or arrange to receive a copy, please register your interest via the Cal Gavin website (http://www.calgavin.co.uk/contacts/contacts.htm).

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Heat Exchange - from Concept Phase to Economic Analysis

From the concept phase of a process plant project through engineering, procurement and construction phases, all parties concerned want to know how much the plant will cost. This is what Aspen Icarus technology is about. Aspen Icarus technology develops economic evaluations - capital and operating costs and associated economic metrics. Aspen Icarus software products are geared to work with available data pertinent to one or more phases along the project time line. Table 1 provides a profile of four Aspen Icarus economic evaluation products and their usage along the project time line.

Table 1



What's the significance of all of this to your heat exchange (HX) work? First, let's take a look at a survey of seven different projects listed in Table 2. The projects ranged from $25 million on upward to more than $800 million. What is important to note is that heat exchange equipment constituted, on the average, close to 30% of the total cost of equipment and equipment count. For the projects studied, the population of exchangers seemed less variable than the cost, with HX costs for Study 2 coming in at 65% of the total equipment cost. Important? Yes!

Table 2

With this focus, we can review the process of starting with a concept of a process to developing the scope for a process project. Often, your work at the conceptual stage is consumed in a process simulation environment which readily embeds TASC and Hetran exchanger models. Traditionally, it's a long step from this phase into capital evaluation. But with a button click in Aspen Plus or HYSYS®, your process simulation results will automatically roll into your choice of two Aspen Icarus products (see Table 1) - Aspen Icarus Process EvaluatorTM (IPE) or Aspen Decision AnalyzerTM (Analyzer). This means that your HX simulation stream and design results will transfer hands-free into IPE and Analyzer along with results for every other type of simulator object. On specifying materials of construction and your choice of a variety of other project specifications, you will obtain capital and operating costs for the project: individual components, installation materials, construction, engineering and a planning schedule. As one user exclaimed, "I can get an estimate inside of 15 minutes after a simulation and spend the rest of my time sharpening the results."

Other fast track ideas might save you time and effort such as using an air cooler followed by a tubular exchanger. Or, arrange the HX units in parallel, or in series or both. IPE and Analyzer can do the duty splits for you and on choosing TEMA type,



develop the costs of these configurations.

As a result of combining Aspen Tech and HTFS HX technologies and Aspen Icarus, the move is on to further integrate and unify. For example, in addition to bringing heat exchanger design and simulation into unified Tasc+ and Acol+ products, AspenTech is building common module for exchanger mechanical design and costing to be used throughout its Aspen Engineering Suite (AES).

This means that your heat exchange studies can be performed

Faster, because of the link to Aspen Icarus to obtain outline mechanical designs and costs More accurately, by eliminating errors in manual data transfer Consistently, because of the use of the same design and cost methods everywhere along the project time line In a shorter time span during each phase of the project time line and along the time line With a reduction in learning and relearning as a result of integrating user interfaces At potentially lower cost of ownership (one integrated product doing the work of two similar stand-alone products) More profitably to your company

Summarizing, from concept phase to Aspen Icarus economic evaluation, we are increasing your capacity and conductivity, decreasing friction, enabling an increased throughput - with a potential decrease in your ownership cost. With heat exchangers such an essential part of the process, this is progress that drives process profitability.

For additional information, please email: [email protected] or complete the web form at: aspentech.com/contact.cfm

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Training

Check out our training web site at: support.aspentech.com/supportpublictrain/TrainHome.htm

Full course descriptions can be viewed and you can register online.

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Current Products



TASC 5.10TM / Aspen Hetran 12.1TM Design and performance simulation of all your shell and tube heat exchanger requirements, including thermosyphons

Aspen Teams 12.1® / TASC Mechanical 5.10TM

Mechanical design of shell and tube heat exchangers

ACOL 6.30TM / Aspen Aerotran 12.1TM

Software for design and performance simulation of air cooled heat exchangers and simulation of heat recovery units, air conditioning and refrigeration exchangers

APLE 2.10TM

A single package for design, rating and performance simulation of gasketed plate and frame heat exchangers

MUSE 3.30TM

Performance simulation layer by layer, crossflow calculation and 'first-shot' thermal design of multistream plate-fin heat exchangers

FIHR 2.10TM

Simulation of fired process heaters

FRAN 2.01TM

Rating and performance simulation of power plant feedwater heaters

PIPE 5.20TM

Single phase and two phase flashing flow calculations in unbranched pipeline systems

TICP 1.0TM

Thermal insulation calculation

HTFS Research Network TM www.htfs.com/resnet.asp

The HTFS knowledge base developed over the past 35 years. This includes online access to the Handbook, research reports and a selection of design reports via the web. Customers can also have a close involvement in directing our research and the evolution of our products through participation on Review Panels.

Review Panel Chairmen Tubular Heat Exchangers Jim McNaught Furnaces & Fired Heaters Asaad Kenbar

Compact Heat Exchangers Vishwas Wadekar

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To contact us

E-mail: [email protected] Web: www.htfs.com



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Details of further office locations can be found at:

www.aspentech.com/corporate/locations.cfm

Technical Support Centres

e-mail: [email protected] support.aspentech.com/SupportPublic/centers.html

See the website for a complete list of phone & Toll-free numbers in your area

Europe, Middle East and Africa (EMEA) + 32 2 701 95 55

North America, Latin America (NALA) + 1 888 996 7100 (Toll-free from US, Canada, Mexico) + 1 281 584 4357 (from outside US, Canada, Mexico)

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+ 81 3 3262 1743 (Tokyo, Japan) + 61 7 5448 1355 (Australia)

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Aspen Technology, Inc., Worldwide Headquarters, Ten Canal Park, Cambridge, MA 02141-2201, USA

Tel:+1 617 949 1000 Fax:+1 617 949 1030



hotline+ - Aspen Technologyhtfs.aspentech.com/Newsletters/pdfs/apr2004.pdf · and FIHRTM 2.10, providing continuing improvements and developments to the ... supersedes the FOCP spreadsheets.

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