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Optimum heat storage design for heat integrated multipurpose batch plants

Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2011.

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Other Authors: Prof T Majozi
Format: Thesis
Language:English
Published: University of Pretoria 2013
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access_status_str Open Access
author2 Prof T Majozi
author_browse Prof T Majozi
author_facet Prof T Majozi
collection Thesis
dc_rights_str_mv © 2011 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2011.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:39:54.964Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
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publisher University of Pretoria
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spelling oai:repository.up.ac.za:2263/30971 Optimum heat storage design for heat integrated multipurpose batch plants Prof T Majozi janestamp@gmail.com Stamp, Jane Dorothy UCTD Energy optimisation Multiproduct Multipurpose Heat storage Heat integration Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2011. The application of heat integration to minimise energy usage in multipurpose batch plants has been in published literature for more than two decades. Direct heat integration may be exploited when the heat source and heat sink processes are active over a common time interval. Alternately, indirect heat integration involves using a heat transfer fluid for storing energy and allows heat integration of processes regardless of the time interval. This is possible as long as the heat source process takes place before the heat sink process. This allows heat to be stored and then used later when required. In both cases, heat transfer may only take place if the thermal driving forces allow. For most present methods, the schedule tends to be fixed and as such, time is also fixed a priori, which leads to suboptimal results. The method presented in this dissertation treats time as a variable and consequently leads to improved results. Both direct and indirect heat integration are considered as well as the optimisation of the heat storage size and the initial temperature of the heat storage fluid. The mathematical formulation is based on an uneven discretisation of the time horizon and the state sequence network (SSN) recipe representation, which has proven to result in mathematical models with fewer binary variables compared to models based on other representations (Majozi&Zhu, 2001). The resulting model exhibits the mixed integer nonlinear programming (MINLP) structure, which implies that global optimality cannot generally be guaranteed. However, a procedure is presented that seeks to find a globally optimal solution, even for nonlinear problems. Heat losses from the heat storage vessel are also considered. This work is an extension of the MILP model of Majozi (2009), which was in fact more suited to multiproduct rather than multipurpose batch facilities. The addition of heat storage instead of using only direct heat integration leads to increased flexibility in the process and therefore improved energy usage. Optimising the size of the heat storage vessel as well as the initial temperature of the heat storage fluid decreased the requirement for external hot utility for an industrial case study by 33% compared to using known parameters. Chemical Engineering MEng (Chemical Engineering) restricted 2013-09-09T07:54:07Z 2011-09-22 2013-09-09T07:54:07Z 2011-09-05 2011-09-22 2011-07-06 Dissertation Stamp, JD 2011, Optimum heat storage design for heat integrated multipurpose batch plants, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-07062011-132048/ > C11/9/140/ag http://hdl.handle.net/2263/30971 http://upetd.up.ac.za/thesis/available/etd-07062011-132048/ en © 2011 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Energy optimisation
Multiproduct
Multipurpose
Heat storage
Heat integration
Optimum heat storage design for heat integrated multipurpose batch plants
title Optimum heat storage design for heat integrated multipurpose batch plants
title_full Optimum heat storage design for heat integrated multipurpose batch plants
title_fullStr Optimum heat storage design for heat integrated multipurpose batch plants
title_full_unstemmed Optimum heat storage design for heat integrated multipurpose batch plants
title_short Optimum heat storage design for heat integrated multipurpose batch plants
title_sort optimum heat storage design for heat integrated multipurpose batch plants
topic UCTD
Energy optimisation
Multiproduct
Multipurpose
Heat storage
Heat integration
url http://hdl.handle.net/2263/30971
http://upetd.up.ac.za/thesis/available/etd-07062011-132048/