1,217 research outputs found
New column configurations for pressure swing batch distillation II. Rigorous simulation calculations
The pressure swing distillation in different batch column configurations is
investigated by rigorous simulation calculations. The calculations are made by a
professional flow-sheet simulator for the separation of a minimum (ethanolâtoluene) and
a maximum boiling (waterâ ethylene-diamine) azeotropic mixture. Besides studying the
well known configurations (rectifier, stripper) we also investigate two novel
configurations such as double column batch rectifier and double column batch stripper.
The alternate application of a batch rectifier and a batch stripper is also studied. The
different column configurations are compared
Entrainer selection for pressure swing batch distillation
The feasibility of the separation of binary homoazeotropes with pressure swing batch
distillation by the application of an entrainer is studied. The feasibility studies are based
on the assumption of maximal separation and on the analysis of batch
distillation/stripping regions and the vessel path in the residue curve map of the ternary
mixture. The following configurations are investigated: batch rectifier, batch stripper,
double column batch rectifier and double column batch stripper. Rules for the selection
of an entrainer are suggested
Generalised model for heteroazeotropic batch distillation with variable decanter hold-up
A general model of batch heteroazeotropic distillation is proposed. Both liquid phases present in the decanter can be refluxed or withdrawn as distillate, their hold-up can be increased, decreased or kept constant, as well. By assuming maximal separation, that is, that the composition of the condensate always equals to that of the heteroazeotrope, the still path equation was derived. The still path directions are determined for all the 16 possible operational policies. It is possible to steer the still path in a desired direction by changing the operational parameters, which allows the recovery of a pure component in the still. The still path directions are validated by rigorous simulations for three policies not published yet using the mixture water â formaldehyde â propyl formate. From the 16 operational policies, 11 can be considered as useful in practice. To demonstrate the advantage of using a non-traditional policy, the separation of the mixture aniline â ethylene glycol â water was investigated, as well. By using a non-traditional operational policy with hold-up reduction in the decanter a higher purity of ethylene glycol was obtained in the still
A nettĂł jelenĂ©rtĂ©k maximalizĂĄlĂĄsa erĆforrĂĄs-korlĂĄtos projektekben - egy Ășj harmĂłniakeresĆ metaheurisztika (A harmony search metaheuristic for the resourceconstrained project scheduling problem with discounted cash flows)
Ebben a tanulmĂĄnyban a szerzĆ egy Ășj harmĂłniakeresĆ metaheurisztikĂĄt mutat be, amely a minimĂĄlis idĆtartamĂș
erĆforrĂĄs-korlĂĄtos ĂŒtemezĂ©sek halmazĂĄn a projekt nettĂł jelenĂ©rtĂ©kĂ©t maximalizĂĄlja. Az optimĂĄlis ĂŒtemezĂ©s elmĂ©letileg kĂ©t egĂ©sz Ă©rtĂ©kƱ (nulla-egy tĂpusĂș) programozĂĄsi feladat megoldĂĄsĂĄt jelenti, ahol az
elsĆ lĂ©pĂ©sben meghatĂĄrozzuk a minimĂĄlis idĆtartamĂș erĆforrĂĄs-korlĂĄtos ĂŒtemezĂ©sek idĆtartamĂĄt, majd
a mĂĄsodik lĂ©pĂ©sben az optimĂĄlis idĆtartamot feltĂ©telkĂ©nt kezelve megoldjuk a nettĂł jelenĂ©rtĂ©k maximalizĂĄlĂĄsi
problĂ©mĂĄt minimĂĄlis idĆtartamĂș erĆforrĂĄs-korlĂĄtos ĂŒtemezĂ©sek halmazĂĄn. A problĂ©ma NP-hard
jellege miatt az egzakt megoldĂĄs elfogadhatĂł idĆ alatt csak kismĂ©retƱ projektek esetĂ©ben kĂ©pzelhetĆ el.
A bemutatandĂł metaheurisztika a CsĂ©bfalvi (2007) ĂĄltal a minimĂĄlis idĆtartamĂș erĆforrĂĄs-korlĂĄtos ĂŒtemezĂ©sek
idĆtartamĂĄnak meghatĂĄrozĂĄsĂĄra Ă©s a tevĂ©kenysĂ©gek ennek megfelelĆ ĂŒtemezĂ©sĂ©re kifejlesztett harmĂłniakeresĆ
metaheurisztika tovĂĄbbfejlesztĂ©se, amely az erĆforrĂĄs-felhasznĂĄlĂĄsi konfliktusokat elsĆbbsĂ©gi
kapcsolatok beĂ©pĂtĂ©sĂ©vel oldja fel. Az ajĂĄnlott metaheurisztika hatĂ©konysĂĄgĂĄnak Ă©s Ă©letkĂ©pessĂ©gĂ©nek szemlĂ©ltetĂ©sĂ©re szĂĄmĂtĂĄsi eredmĂ©nyeket adunk a jĂłl ismert Ă©s nĂ©pszerƱ PSPLIB tesztkönyvtĂĄr J30 rĂ©szhalmazĂĄn
futtatva. Az egzakt megoldås generålåsåhoz egy korszerƱ MILP-szoftvert (CPLEX) alkalmaztunk. _______________ This paper presents a harmony search metaheuristic
for the resource-constrained project scheduling problem with discounted cash flows. In the proposed approach, a resource-constrained project is characterized by its âbestâ schedule, where best
means a makespan minimal resource constrained
schedule for which the net present value (NPV)
measure is maximal. Theoretically the optimal schedule searching process is formulated as a twophase
mixed integer linear programming (MILP)
problem, which can be solved for small-scale projects
in reasonable time. The applied metaheuristic is based
on the "conflict repairing" version of the "Sounds of
Silence" harmony search metaheuristic developed by
Csébfalvi (2007) for the resource-constrained project
scheduling problem (RCPSP). In order to illustrate
the essence and viability of the proposed harmony
search metaheuristic, we present computational results for a J30 subset from the well-known and popular PSPLIB. To generate the exact solutions a state-of-the-art MILP solver (CPLEX) was used
PszicholĂłgia pedagĂłgusoknak
Régóta våratott magåra egy pszichológiai tankönyv, amely a korszerƱ ismereteket a gyakorlati pedagógiai munkåban is felhasznålható formåban adja közre. Most azonban végre kézbe veheti tanår, oktató és hallgató. Pszichológusként irigykedéssel tekintek erre a kötetre, hiszen hazai szakember tollåból ennél alaposabb és naprakészebb pszichológusoknak szóló kézikönyv nem jelent meg a piacon
New double column system for heteroazeotropic batch distillation
A new double column system (DCS) operated in closed mode is suggested for heterogeneous batch distillation. This configuration is investigated by feasibility studies based on the assumption of maximal separation and is compared with the traditional batch rectifier (BR). We study the configurations also by dynamic simulation based on a detailed model using a professional simulator. For the new configuration the minimal duration of the process is determined. The influence of the most important operational parameters is studied. The calculations and the simulations are performed for a binary (n-butanolâwater) and for a ternary heteroazeotropic mixture (isopropanolâwater + benzene as entrainer). One of the advantages of the DCS is that distillation of binary and ternary systems is performed in only one step. Furthermore the recovery of components is usually higher and the amount of byproducts is lower
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