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Recent content by rense
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Hypothetical components in DW Sim
can't you contact the developer ? see your other thread for site https://www.eng-tips.com/viewthread.cfm?qid=457439 about your question, it would be better to provide more information about your problem, depending from problem, you may know the properties of a chemical (critical, volumetric...- rense
- Post #2
- Forum: Chemical process development
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LPG blend in a closed vessel
www.google.com/search?q=chemputers1994.pdf as alternative you may wish to consider simplified models, with these you can try to compute the integral analytically (solving differential mass balances at specified conditions), an example is the Rayleigh equation but several other cases are...- rense
- Post #10
- Forum: Chemical process engineering
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LPG blend in a closed vessel
you know the initial conditions (compositions and volume of vessel), at each time step you subtract a predefined amount (vapor and/or liquid phase) , from mass balance calculate and define the new composition (remember you have fixed volume for vessel and different specific volumes for vapor /...- rense
- Post #7
- Forum: Chemical process engineering
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LPG blend in a closed vessel
you know initial composition and, from mass balance, you can calculate compositions (vapor and liquid at equilibria) at different time steps, a simple model could be based on ideal gas law and vapor pressure of different components but if you need accurate results consider a EOS, with simple...- rense
- Post #4
- Forum: Chemical process engineering
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Help : HYSYS Properties of Liquid-Aqueous Mixture
Iomcube, Not sure if that is what you are looking for but there is a simple Excel page which calculates the properties in different zones (see image) it works with all versions of Prode Properties, including free...- rense
- Post #7
- Forum: Chemical process engineering
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VLE equilibrium/physical properties validation of a multicomponent system (CO2-MEA-H2O) inAspenPlus?
perhaps you can estimate binary fractions based on definition of loading, for carbon dioxide, monoethanolamine and water ternary probably you need a model with support for electrolytes as the E-NRTL , however these models are complex including many equilibrium contants and I doubt you can...- rense
- Post #2
- Forum: Chemical process engineering
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Help : HYSYS Properties of Liquid-Aqueous Mixture
the normal procedure is to divide exchanger in zones and then calculate conditions and transport proerties in each zone, with those values you can estimate velocities, Prandtl Numbers (or equivalen parameters and so on...) for that you need to solve phase equilibria at specified H (with a H-P...- rense
- Post #4
- Forum: Chemical process engineering
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Help : HYSYS Properties of Liquid-Aqueous Mixture
simulators can include several models for mixtures, for example my copy of Prode Properties includes several models discussed in The Properties of Gases and Liquids (which I adopt as reference in many cases). Many different rules have been proposed (in literature) for example, for ideal liquid...- rense
- Post #2
- Forum: Chemical process engineering
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Very high pressure gas relief - supercritical - Z>2
I have used the integral method (HEM model) in Prode for pressures up to 900-1000 Bar, in principle there are no limits but I never found such high values (3000 Bar) as reported for this application..- rense
- Post #10
- Forum: Safety Relief Valve engineering (PSV)
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Calculation of Fan work by VdP and the adiabatic process where PV^(gamma) = Constant; which is OK?
it is difficult to provide comments without knowing what you are doing, show us your calc's in both cases (for example for air) and someone may help.- rense
- Post #9
- Forum: Heat Transfer & Thermodynamics engineering
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Control Valve two-phase flow with PRODE software
when sizing for two phase flow you can expect higher errors, don't know the very last ISA edition but, according my knowledge, ISA formulations are not reliable for two phase flow, when possible I ask manufaturer to provide calc's, anyway there are a few methods as HNE-DS which may be...- rense
- Post #2
- Forum: Chemical process engineering
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Depressurization Fundametal
most simulators solve a blowdown mainly from a thermodynamic point of view, meaning at n steps (P initial->P final) a mass & heat balance is solved in the way suggested by T2k, to understand how it works you can solve for example a series of H-V flash or some equivalent operations, being...- rense
- Post #4
- Forum: Safety Relief Valve engineering (PSV)
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Vapor pressure and boiling point of liquid mixture
to start you can adopt the same procedures but calculating fugacity of vapor and liquid phase with a EOS such as Peng Robinson or Soave, this requires some initialization for vapor and liquid compositions (see Wilson correlation for example) Details are discussed in many books, for example The...- rense
- Post #3
- Forum: Chemical engineering other topics
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Process optimization
yes, you should be more specific, however I have utilized Matlab in union with a thermodynamic library (Prode Properties) for simple problems, Matlab includes good minimizers but you need to compile in order to get reasonably fast executions. Another possibility is that you compile and link with...- rense
- Post #2
- Forum: Chemical process engineering
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Specific vapor and liquid enthalpies in multi-component systems
possibly you can validate yourself the solution, as first step check predicted densities for vapor and liquid phases then get compositions for liquid and vapor phase at equilibria since for vapor and liquid H = SUM(Wi*Hi) where Wi is weight fraction of component i and Hi is enthalpy of component...- rense
- Post #6
- Forum: Heat Transfer & Thermodynamics engineering
