ASPEN format

Rowell etal. (1987b) produced PF-bonded flakeboard from acetylated southern pine (21.6 % WPG) or aspen (17.6 % WPG) flakes. This was not completely resistant to attack by termites Reticulitermes flavipes) in a 4-week test. It was thought that acetylation was less effective in preventing termite attack than other chemical modifications because cellulose decomposition in the intestines of termites leads to acetic acid formation in any case. 

Kvamme, B. Graue, A. Aspenes, E. Kuznetsova, T. Granasy, L. Toth, G. Pusztai, T. Tegze, G. (2004). Kinetics of solid hydrate formation by carbon dioxide Phase field theory of hydrate nucleation and magnetic resonance imaging. Phys. Chem. Chem. Phys., 6, 2327-2334. 

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Abstract In this paper, we discuss the results of a preliminary systematic process simulation study the effect of operating parameters on the product distribution and conversion efficiency of hydrocarbon fuels in a reforming reactor. The ASPEN One HYSYS-2004 simulation software has been utilized for the simulations and calculations of the fuel-processing reactions. It is desired to produce hydrogen rich reformed gas with as low as possible carbon monoxide (CO) formation, which requires different combinations of reformer, steam to carbon and oxygen to carbon ratios. Fuel properties only slightly affect the general trends. 

Physical property data for many of the key components used in the simulation for the ethanol-from-lignocellulose process are not available in the standard ASPEN-Plus property databases (11). Indeed, many of the properties necessary to successfully simulate this process are not available in the standard biomass literature. The physical properties required by ASPEN-Plus are calculated from fundamental properties such as liquid, vapor, and solid enthalpies and density. In general, because of the need to distill ethanol and to handle dissolved gases, the standard nonrandom two-liquid (NRTL) or renon route is used. This route, which includes the NRTL liquid activity coefficient model, Henry s law for the dissolved gases, and Redlich-Kwong-Soave equation of state for the vapor phase, is used to calculate properties for components in the liquid and vapor phases. It also uses the ideal gas at 25°C as the standard reference state, thus requiring the heat of formation at these conditions. 

It has been shown that the xanthate method could be successfully applied in order to graft hardwood high yield bisulfite pulp made of aspen. The optimum grafting condition, which would give almost 100% grafting efficiency (i.e.,100% formation of true graft and no homopolymer) and rather high monomer conversion of 80% are as follows ... 

Figure 2-22 Trans Isomer Formation in Sunflower Oil as a Function of Deodorization Temperature. Source Reprinted from R.G. Ackman, Animal and Marine Lipids, in Improved and Technological Advances in Alternative Sources of Lipids, B. Kamel and Y. Kakuda, eds., p. 301, 1994, Aspen Publishers, Inc.

Beatson RP, Heitner C, Rivest M, Atack D (1985) Sulphite treatment of aspen Factors affecting the formation of carboxylate and sulphonate groups Pap Puu 11 702-708 Brauns FE (1952) The sulfonation of lignin In Brauns FE (ed) The chemistry of lignin Academic Press, New York, 359-393... 

Figure 13 Influence of temperature on phenolic hydroxyl group formation in treatments of Norway spruce and aspen wood lignin with O.l M HCI. (From Ref. 316.)...

The Application-Specific Layer holds classes and relations that are required for particular tasks or applications. Figure 2.4 shows exemplarily a module for the description of model files that are available in the format of the process simulator Aspen Plus [518[. 

CHEOPS obtains this setup file in XML format from ModKit-l-. Tool wrappers are started according to this XML file. The input files required for the modeling tools Aspen Plus and gPROMS are obtained from the model repository ROME. CHEOPS applies a sequential-modular simulation strategy implemented as a solver component because all tool wrappers are able to provide closed-form model representations. The iterative solution process invokes the model evaluation functionality of each model representation, which refers to the underljdng tool wrapper to invoke the native computation in the modeling tool the model originated from. Finally, the results of all stream variables are written to a Microsoft Excel table when the simulation has terminated. 

Calculated based on heat of formation simulated by Aspen Plus and heat of combustion measured experimentally. 

Gabrielii, I., Gatenholm, P., Glasser, W.G., Jain, R.K., Kenne, L. Separation, characterization and hydrogel-formation of hemicellulose from aspen wood. Carbohydr. Polym. 43, 367-374 (2000)... 

Figure 3.5 also shows the heats of reaction for the two reaction steps. These are computed at the temperatures and pressures of the reaction operations from heats of formation and heat capacities as a function of temperature. There are many sources of this data, especially the process simulators that are discussed in Chapter 4. When a simulator, such as ASPEN PLUS, is used, it is convenient to define each of the reaction operations and to perform an energy balance at reactor conditions. The simulators report the rate at which heat must be transferred to or from the reactor to achieve exit conditions from given inlet conditions or, if operated adiabatically, the exit conditions for no heat transfer, as discussed on the multimedia CD-ROM (ASPEN — Chemical Reactors and HYSYS Chemical Reactors) that accompanies this text... 

Note that the Calculate text box must be in the strict FORTRAN format, which for our purposes means that we must insert six spaces before each line. When finished (and the blue checkbox appears in the Calculate tab to indicate that there were no syntax errors), verify that the Sequence tab will execute the calculator block use (ing) import/export variables. This means that Aspen Plus will call this calculator block at some point in the SM sequence when all of the import variables are available, but the export variables still need to be calculated. For this example, this occurs precisely after MIXl and before MIX2. A savvy user could control this manually by specifying that it should execute before MIX2, but the default setting is usually adequate. When finished, run the simulation and verify that the makeup content has changed (it should be about 7.6 kmol/h H2O and about 0.001 kmol/h MDEA). At this point, saving a backup copy of the simulation in a separate file is recommended. 

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