• Frequently Asked Questions

Frequently asked questions about CHEMCAD

Answers to your general and technical questions about CHEMCAD. If you have questions on specific software features, please see our full feature list

Q. What is the best use of simulation software?

A. This question has different answers if the user works for a chemical company, refinery, engineering firm, pharmaceutical company, etc. In general, the best uses of a simulator are as follows: (1) Investigating a new process by simulating various alternatives to determine the feasibility of each; (2) Simulating an existing process to determine optimal conditions, bottlenecks, or sensitivity to process changes; (3) Simulating an existing process to determine control schemes, dynamic behavior, etc.; (4) Day-to-day engineering work (e.g. bubble/dew points, fluid properties, equipment sizing).

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Q. How much financial benefit can I expect to gain from CHEMCAD?

A. Well, the answer is really up to you! Because CHEMCAD is a productivity tool, it simply allows you to do far more than you can with other tools (honestly, if you had a lifetime or two to solve all the equations that CHEMCAD does, you could get the same answers with a pencil and paper). This means that an engineer can be as much as 100 times more productive with CHEMCAD. Obviously, without computer simulation tools, many shortcut methods are employed to speed up calculations, yet they are limited by their lack of rigor. This is where the additional benefit of simulation comes into play. Once your thermodynamics are verified, you can achieve answers to a far greater degree of accuracy than with other tools. Accuracy of your model allows more intelligent decision-making, and in turn, greater economic benefit.

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Q. Can I run CHEMCAD on a network?

A. Yes, you can run CHEMCAD on a network. The software is protected using a dongle hardware key by default. This can be attached to any PC, networked or not. However, to let everyone on a network (Local or Wide Area) have access to Chemstations' software, you must purchase our Network Hardware/Software solution. This is either a network-dongle or software system (depending on the type of network you have) that allows users to access the software. The network dongle or software system can be attached/installed on any machine on the network. The number of simultaneous users is the number of licenses you own. That is, if you own two copies/licenses of CHEMCAD, you may have two users access CHEMCAD at any given time. The third person to try to access CHEMCAD will be rejected by the network security system. Please contact a Chemstations representative to ensure that your network type is supported.

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Q. Is CHEMCAD a client-server type application?

A. No. CHEMCAD is a fully integrated software package. The graphical interface is completely tied into the calculations portion of the program in this way. There is no batch-type communication between interface and calculational engine to slow the program down. It is possible, however, to install CHEMCAD on a network server and run the program from client machines. In this case, the client machine is actually doing ALL of the calculations. Typically, we find that this slows down the program significantly, so we recommend installing to the client machine(s), if at all possible.

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Q. Is it easy to share work with other users?

A. Yes. CHEMCAD simulation files can be e-mailed, placed on a portable drive, or stored on a shared network drive, then opened on another machine with access to a valid CHEMCAD license.

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Q. How long does it take to learn CHEMCAD?

A. Unfortunately, there is no easy answer to this question. Without training, we find that our users who are simulation literate tend to pick up the basics fairly quickly (1-2 weeks continuous use, 5-6 weeks infrequent use). Those who are new to simulation tend to take significantly longer without training. The interface is extremely easy to pick up for almost anyone; those new to simulation simply need time to understand flowsheeting/thermodynamics selection/convergence issues. With training (our BASIC course), users typically can begin useful modeling as soon as they return to the workplace. The reason for this is that our training course is less "keystroke-oriented" and more "method-oriented."

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Q. How many components (chemicals) may I have in a simulation?

A. You can have up to 2000 components in any given simulation.

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Q. Can I add my own unit operations, thermodynamic methods, or other routines to CHEMCAD?

A. Yes, CHEMCAD allows you to add a new unit operation as an Excel spreadsheet, as a user-programmed C++ .DLL, or as a user inline C program. You can add a thermodynamic method as a C++ .DLL. Other routines, for calculating properties or functions not provided for within CHEMCAD, can be added as Excel spreadsheets, .DLLs, or inline C programs. You can add your own graphical user interface screens using very simple tools distributed with the program.

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Q. Can CHEMCAD model dynamic processes?

A. Yes, CHEMCAD will model dynamic processes with our add-on CC-DYNAMICS package. This product enables generalized dynamic flowsheeting in addition to dynamic distillation/reaction.

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Q. Can I add my own chemicals to CHEMCAD?

A. Yes. You can have CHEMCAD predict physical properties based on chemical structure (if you have no data available), you can enter equation coefficients for temperature dependent data, or you can have CHEMCAD regress these coefficients from your temperature-dependent data.

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Q. Does CHEMCAD have equipment costing functions?

A. Yes, CHEMCAD can perform equipment costing. However, as with most costing algorithms, the answers produced are far more useful as a first-pass or comparison tool than as an actual budgeting tool.

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Q. What type of printouts, plots, and reports can I get from CHEMCAD?

A. CHEMCAD provides its own report and plot displays for onscreen viewing and printing; you can also choose to export your data to WordPad, MS Word, or Excel. You can print out a flowsheet directly from the main CHEMCAD window.

Graphics can be sent to a printer or plotter using Windows print drivers to your particular printer/plotter. In addition, graphics can be sent to a .DXF file (on disk) or a .WMF file (on the clipboard).

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Q. What engineering units does CHEMCAD work in?

A. You can select from pre-built engineering profiles (ENGLISH, FORMAL SI, COMMON SI, or METRIC), or create your own profile of mixed units. You can save profiles and/or create default profiles to be used with every new simulation.

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Q. Can I edit the data in the CHEMCAD physical property database?

A. To preserve the integrity of our built-in component database, we require that you clone and then edit an existing component, rather than edit the original component.

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Q. Will CHEMCAD tell me which thermodynamic option applies to my chemical system?

A. Yes and no. CHEMCAD has a built-in Thermodynamics Wizard, which follows an algorithm based on your chemical components and your expected temperature and pressure ranges. This algorithm is fallible, and no algorithm can claim to always find the correct method. The CHEMCAD Help system contains both a description of the process you should follow to choose a method and elaborate descriptions of each method (including equations solved). Often you will have to verify your thermodynamic method with field or laboratory data. However, do not think of this as a barrier to using simulation; rather, think of it as an investment in your process. Once it's verified, your model will be infinitely more valuable than an unverified model.

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Q. What type of flowsheet convergence does CHEMCAD use?

A. By default, CHEMCAD is a sequential-modular simulator. This means that given feed streams and unit operation specifications, CHEMCAD will calculate intermediate and outlet streams. CHEMCAD also has a simultaneous modular mode for convergence.

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Q. Do I have to run my entire simulation, or can I just run sections?

A. You can run the entire simulation, certain sections, certain recycle loops, or just individual unit operations if you like.

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Q. Can I make a PFD (Process Flow Diagram) in CHEMCAD?

A. Yes. You can add stream data boxes, unit operation data boxes, text labels and titles, user-created shapes/pictures/lines, and imported .BMP files to your flowsheet.

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Q. Can I make a piping and instrumentation (P&I) diagram in CHEMCAD?

A. In most cases, a CHEMCAD process flow diagram (PFD) can be used as a starting point for a P&I diagram. CHEMCAD is not a drawing program; rather, it is a simulator with drawing features. Therefore, it is most typical for a PFD from CHEMCAD to be exported to a .DXF file, then modified in a drawing program like Autodesk's AutoCAD or Intergraph's SmartPlant.

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Q. Does CHEMCAD use any industry standard for data exchange?

A. We currently support OPC, OLE, and COM. We are also committed to implement any future standard adopted for the chemical processing industry.

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Q. What language is CHEMCAD programmed in?

A. CHEMCAD is programmed in Visual C++.

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Q. Can CHEMCAD simulate my process?

A. Almost any chemical process can be simulated in CHEMCAD. We can say this simply because of the flexible foundation that we provide for you. For example, if you are interested in tracking fluid properties that CHEMCAD does not calculate, then you can write a user-added subroutine to calculate those properties. If you have a unit operation that is not in the CHEMCAD unit operation palette, you can either model it from a group of existing unit operations or create it yourself using an Excel spreadsheet or a C program. At the very least, you can employ a "black box" type of unit operation.

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Q. Does CHEMCAD have helpful error messages?

A. CHEMCAD displays all error messages in the Errors and Warnings tab; these error messages are as helpful as we can make them. In most cases, you are prevented from entering conflicting specifications, overspecifying, or underspecifying, but errors can still result from problematic input. For example, if you specify an unreachable composition in a distillation column, you will either get a mathematical error or a message that the column "dried up"-you won't get a warning before you try to run the column, and you won't get a message saying that you specified an unreachable composition. The CHEMCAD Help system offers helpful tips for avoiding such outcomes, especially where distillation columns are concerned.

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Q. How is CHEMCAD distributed?

A. CHEMCAD is distributed on a single CD. The hardware dongle, system authorization, or network security software determines which CHEMCAD products and how many licenses are active.

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Q. How is the software updated?

A. About once a year, Chemstations releases a major upgrade (numbered with a tenth or new whole number, e.g., 6.0, 6.1). Throughout the year, however, we are constantly improving the product and adding functionality. Users who are on a current MUS (Maintenance, Upgrades, and Support) agreement are advised to watch the Web site for new releases as they become available. These releases, along with lists of new features, can be found on the Downloads page of the Chemstations Web site.

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Q. Does Chemstations do modeling, simulation, or consulting for its customers?

A. No, and this benefits our clients in the following way: We are never tempted to turn a technical support issue into a money-making opportunity. There is a point at which technical support cannot continue, as we cannot do the work for you, but can only assist you while you do the work. We are happy to recommend consultants who can do the work for you using CHEMCAD, but our technical support department is not a gateway to a consulting business.

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