Aspen program

Start the Aspen program, select Aspen Plus User Interface, and when the Connect to Engine window appears, use the default Server Type Local PC. Select Pipe under the Pressure Changes tab from the Equipment Model Library and then click on the flow sheet window where you would like the piece of equipment to appear. In order to add material streams to the simulation, select the material stream from the Stream Library. When the material stream option is selected, a number of arrows will appear on each of the unit operations. Red arrows indicate a required stream and blue arrows indicate an optional stream. 

Pure water is fed at a rate of 100 Ib/h into a pump at 250°F, 44.7 psia. The exit pressure is 1200 psig. Use the pump module in HYSYS, PRO/II, and Aspen programs to model the pumping process. The pump adiabatic efficiency is 10%. Find the energy required. 

Start the Aspen program. The Connect to Engine window will appear you should select the default Server Type (Local PC). 

Costing and economic evaluation programs also form part of some of the commercial process design packages such as the ICARUS program which is available from Aspen Tech, see Chapter 4, Table 4.1. 

Design of extraction processes and equipment is based on mass transfer and thermodynamic data. Among such thermodynamic data, phase equilibrium data for mixtures, that is, the distribution of components between different phases, are among the most important. Equations for the calculations of phase equilibria can be used in process simulation programs like PROCESS and ASPEN. 

This is the fun (and frustration) of chemical reaction engineering. While thermodynamics, mass and heat transfer, and separations can be said to be finished subjects for many engineering apphcations, we have to reexamine every new reaction system from first principles. You can find data and construct process flowsheets for separation units using sophisticated computer programs such as ASPEN, but for the chemical reactors in a process these programs are not much help unless you give the program the kinetics or assume equihhrium yields. 

Many aspects of a process can be evaluated with a chemical process flowsheet program such as Aspen. These programs handle mass balances and heat loads on each component with great accuracy. Separation components can also be handled accurately as long as they are rather straightforward. Cost databases also exist on these programs that allow rapid costing of many components. 

At the core of many of these algorithms for solvent substitution is a method for predicting the properties of proposed molecules, given only the molecular structure. Much work has been done in this area alone, and several programs have been developed to guide this process. Some of these programs are listed in table 9.1. Additionally, process simulation software such as Aspen Plus contain several different approaches for the prediction of properties from molecular structure. 

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. 

Several companies (D.B.R. Oilphase/Schlumberger, Infochem Computer Services, Ltd., Calsep) have commercially available computer programs (DBR hydrate, Multiflash, PVTSim) for the prediction of hydrate properties, and such methods are incorporated into process flowsheeting programs such as ASPEN , HYPERCHEM , and SIMCI . Researchers in the CSM laboratory (Sloan and Parrish, 1983 Sloan et al., 1987 Mehta and Sloan, 1996) generated new parameters for the prediction of si, sll, and sH hydrates, which were incorporated into the program, CSMHyd. 

This structure assures correct pressure-flow solutions and, thus keeps the model consistent. Software packages, such as ASPEN Dynamics , will ensure this correct coupling. In general, two flow calculating devices cannot be connected directly, but must have a pressure (typically a volume) element in between. Two flow devices can be connected if a single equation can be written that describes the pressure drop over the connected section. For instance, some programs allow two pipe models to be connected. 

Several important types of reactions are considered in the following sections. The equations describing each of these systems are developed. The steady-state design of CSTRs with these reactions are discussed, using Matlab programs for hypothetical chemical examples and the commercial software Aspen Plus for a real chemical example. 

We click on Start and select Programs, Aspen Tech, Aspen Engineering Suite, Aspen Plus 2004, and Aspen Plus User Interface. The window shown in Figure 2.26 opens. A Blank Simulation is selected, and clicking OK opens a blank flowsheet shown in Figure 2.27. 

The program in Aspen Plus is run and pressure-checked. It is then exported to Aspen Dynamics as a pressure-driven dynamic simulation as was done in Chapter 3 with CSTRs. The Aspen Dynamics file is opened, giving the window shown in Figure 6.37. The default control scheme has a pressure controller manipulating the valve in the reactor exit line. The simulation is run until all variables stop changing. 

The dynamics and control of a number of tubular reactor systems have been studied in this chapter. Both adiabatic and cooled tubular reactors have been explored in both isolation and a plantwide environment. Ideal systems have been studied using Matlab programs. Real chemical systems have been studied using Aspen Dynamics. 

A major development effort has been underway at M.I.T. from 1976 to 1979 to develop a next-generation process simulator and economic evaluation system named ASPEN (Advanced System for Process ENgineering). The 150,000-line computer program will simulate the flowsheet of a proposed or operating plant. In addition to calculating detailed heat and material balances,... 

The ASPEN system is on schedule for a working version to be completed October, 1979. The program system will be comprised of about 150,000 lines of FORTRAN code and data for physical... 

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. 

It is believed that ASPEN provides a state-of-the-art capability for thermodynamic properties of conventional components. A number of equation-of-state (EOS) models are supplied to handle virtually any mixture over a wide range of temperatures and pressures. The equation-of-state models are programmed to give any subset of the properties of molar density, residual enthalpy, residual free energy, and the fugacity coefficient vector (and temperature derivatives) for a liquid or vapor mixture. The EOS models (named in tribute to the authors of such work) made available in ASPEN are the following ... 

As with the rest of ASPEN, the cost estimation and economic evaluation system will be modular in design there will be one program module for each equipment class, and it will be easy for users to add their own costing modules. 

In this case, the stream data can be imported directly from the Aspen Plus report file. The program WAR calculates automatically PEI values for each category and for the whole process on an hourly basis (PEI/h), or with respect to product unit (PEI/kg) - The effect on the environment of the energy used for driving the process can be taken into consideration too. Figure 5.29 illustrates typical data for three cases ... 

Akashah et al. optimum feed, 118.119 Albright random cells, 542 AMSYM program, 171,192 ASPEN system, 163 ASPENPlus system, 163, 177,179 187 192... 

The separation analysis by established methods of McCabe -Thiele or Ponchon Savarit are compared with a flow sheeting program ASPEN+. It will be demonstrated, that a reliable scale -up is possible combining all these methods. 

The simulation of a multi-component system was done with the flow sheeting program Aspen+. An external routine replaced the internal Kj-calculation with a fit function through the experimental Revalues as given in figure 4. The multistage column was split into a cascade of flash modules. Each module is connected to two other... 

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