ASPEN information

The referenced Siemens Westinghouse pnblication presented the cycle concept and overall performance valnes. Neither specific stream information nor assnmptions were presented. The stream data and assumptions presented here were developed by Parsons. The stream data were developed using an ASPEN simulation which yielded performance numbers in general agreement with the publication. 

ASPEN acquired ICARUS in 2000 and developed Process Evaluator based on Questimate that is used for conceptual design, known as front-end loading (FEL). More information on FEE and valueimproving process (VIP) is found later in Sec. 9. Basic and detailed estimates are coupled with a business decision framework in ASPEN-TECH ICARUS 2000. 

To study different operating conditions in the pilot plant, a steady-state process simulator was used. Process simulators solve material- and energy-balance, but they do not generally integrate the equations of motion. The commercially-available program, Aspen Plus Tm, was used in this example. Other steady-state process simulators could be used as well. To describe the C02-solvent system, the predictive PSRK model [11,12], which was found suitable to treat this mixture, was applied. To obtain more reliable information, a model with parameters regressed from experimental data is required. 

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The message shown in Figure 3.60 provides some information about the exported file and indicates the exported file is ready to run in Aspen Dynamics. A simple way to... 

An indepth evaluation of the fFeld was afforded by the ASPEN project at MIT sponsored by the U. S. Department of Energy. The project was started June 1, 1976 and is entitled, "Computer-Aided Industrial Process Modeling". Its quarterly and annual reports are available from the National Technical Information Service ( ). 

ASPEN Project - 1st Annual Report-MIT-2295T9 -4 June 15, 1977 2nd Annual Report-MIT-2295T9-9 June 15, 1978 Available from Contract E(49-18)-2295 Task No. 9, National Technical Information Service, U. S. Dept, of Commerce, 5225 Port Royal Road, Springfield, VA 22161. 

For the data of streams and equipment models, ASPEN utilizes a plex data structure of the type proposed by Evans, et al. (3) Information is stored in blocks of contiguous locations known as beads. Beads of any length are created dynamically from a pool of free storage which may be thought of as a lengthy FORTRAN array. The combination of the preprocessor approach and the plex data structure has resulted in the absence of dimensional constraints on the system. There are no maximum numbers of streams, components, models, stages in a column, etc. except as limited by the total memory available. 

Another potential advancement is permitted in the ASPEN system. Tear streams can be designated as desired, so that a user might define blocks or series of blocks and simulate these sets as quasi-linear blocks. The convergence method could utilize this information and solve the material (and energy) balances explicitly. In this way, a simultaneous modular architecture could be utilized. Implementation of these programs will be for later enhancements of ASPEN, not the initial version. 

Because ASPEN is to be used with coal conversion processes, its streams can be designated to carry an arbitrary number of solids or solid phases. This is done by specifying any number of substreams. In fact, the conventional vapor/liquid stream is normally assumed as a substream and solids can comprise other substreams. For the conventional vapor/liquid substream, process data is carried on component molar flows, total molar flow, temperature pressure, specific enthalpy, specific entropy, density, molar vapor fraction, molar liquid fraction, and molecular weight. For solid substreams, which are called "non-conventional substreams," the characterizing data is not as deterministic. The information associated with these substreams is called "attributes". Such attributes may be particle size distribution, ultimate and proximate analyses, or other material specific information. Another type of substream is an "informa-... 

The next action is to estimate the separation targets and allocate the components in products. For the assessment of a separation a good practice is by setting up a recovery matrix as shown in Table 3.6. This expresses the split of a component between feed and products. Note that this information is available in Aspen Plus when simulating separators. 

An interesting aspect is the relation between the design of units and the quality specifications. The path of each impurity can be traced by paying attention to generation, exit points and accumulation in recycles. In this respect the component split matrix available in Aspen Plus [23] gives very useful information and is highly recommended. 

A combination of DEPT and IGD spectra allows more precise quantitative analysis of, for example, the number of quaternary aromatic carbons. From such results, the degree of carbon-carbon condensation on the aromatic ring can be defined as the number of quaternary carbon atoms that are neither CL nor C4 nor are methoxyl-substituted C3/C5. This kind of information is particularly useful for following condensation reactions during such processes as steam explosion treatment of aspen wood (Robert et al. 1986, Bardet 1987) and kraft cooking (Robert et al. 1984, Gellerstedt and Robert 1987). 

AspenTech has developed and applied quantitative cost-benefit analysis for engineering systems, including applied thermodynamics. The analysis, provided by Aspen Value Process (AVP), is a collaborative process yielding multi-level, broad commitment for business process changes enabled by software solutions. A key outcome of AVP is the customers validation of the estimated value. The financial information is highly sensitive and consequently there are no published cases available. Here, we present the basic approach and give typical quantitative assessment results. One could either carry out an extrapolation of this analysis to assess the industry-wide benefits (as is done below), or, alternatively, carry out a series of these assessments with specific producers. 

ASPENPLUS Aspen Technology [H] Large Aspen Technology Corp., Cambridge, Mass. original Aspen from National Technical Information Service, Springfield, Va. 

You can also use the process simulator Aspen Plus to solve chemical reaction equil-brium problems. It has a huge advantage over Excel and MATLAB Aspen Plus contains the Gibbs free energies of many chemicals, and it can calculate them as a function of temperature. Thus, the data-gathering aspect of the problem is handled for you. Your job is to compare the results and the predicted A -values with experimental information. 

First, the chapter lists the possible unit operations in the Aspen Plus Model Library, because the process is a connected set of the units. Then an example process is illustrated that makes ammonia from nitrogen and hydrogen. You will be able to get both the mass balances and the energy balances for the process. With this information you can determine the size of most of the equipment needed, and hence its cost. You can also determine the operating cost for heating, cooling, compression, and other tasks. The process involves a... 

You expect Aspen Plus to be correct, but there are two possible problems lack of convergence and poor choices of thermodynamic correlations. By using the Nd button to run your problem you will get printed information about the convergence or lack of it. Read the output You get this information from the View/Control Panel menu, too. The proper choice of thermodynamic correlation can only be determined by comparison with experimental data or with experience. (This is one reason why chemical engineers are paid a lot - for their experience.) Naturally, at this point in your career, few of you have that experience. However, you can stUl look at your mass and energy balances and see if they make sense. Every number needs to be examined. 

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