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Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop

Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2010.

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Other Authors: tim.price@erm.com
Format: Thesis
Language:English
Published: University of Pretoria 2013
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dc_rights_str_mv © 2010, 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, 2010.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:40:31.851Z
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
publisherStr University of Pretoria
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spelling oai:repository.up.ac.za:2263/31278 Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop tim.price@erm.com Prof T Majozi Price, Tim UCTD Steam system Boiler efficiency Pressure drop Restructuring Optimisation Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2010. The use of steam in heat exchanger networks (HENs) can be considerably reduced by the application of heat integration and optimisation with the intention of debottlenecking the steam boiler and indirectly reducing the water requirement (Coetzee and Majozi, 2008). The reduction of steam flowrate in a HEN affects the operation of the steam boiler. By reducing the steam flowrate the return condensate temperature to the boiler is compromised which adversely affects the operation of the boiler. A means of maintaining the efficient operation of the boiler whilst still reducing the overall steam flowrate to the HEN is to reheat the return flow to the boiler to a sufficiently high temperature. One means of achieving this is by utilising the sensible heat from the superheated steam leaving the boiler to preheat the boiler feed. Reusing condensate also has the effect of increasing the pressure drop throughout the HEN. The pressure drop is dependent on the size of the heat exchanger or pipe, the flowrate through the exchanger or pipe and also the HEN layout. This creates an intricate situation that must be accounted for. Steam systems typically employ turbines to use energy from superheated high pressure steam to generate shaft work. The exhaust of these turbines is usually saturated steam which is frequently used as a utility in the background process. Since turbines operate at various steam levels, a means for incorporating these steam levels into the HEN optimisation framework is necessary. By reducing the amount of steam required for these HENs an opportunity arises for the use of this steam in further preheating the boiler feed water in an attempt to maintain boiler efficiency. This work involves modelling of the steam system in a mathematical framework and finding the global minimum steam flowrate for the system. The pressure drop throughout the HEN is then also calculated and minimised. The boiler efficiency is maintained by restructuring the HEN and making provision to preheat the boiler feed using synthesis and optimisation. In the event of there not being enough excess heat in the steam system to maintain the boiler efficiency a slight compromise in either boiler efficiency or the minimum flowrate must be made. The initial targeting for the minimum steam flowrate is based on a graphical technique of Coetzee and Majozi, 2008. Consequently, this dissertation concerns the optimisation and restructuring of all steam system heat exchangers using conceptual and mathematical analysis to create a series/parallel HEN with the aim of reducing the overall steam flowrate, whilst maintaining boiler efficiency and minimising the HEN pressure drop. Chemical Engineering MEng (Chemical Engineering) restricted 2013-09-09T12:10:22Z 2010-09-22 2013-09-09T12:10:22Z 2010-09-02 2010-09-22 2010-09-22 Dissertation Price, T 2010, Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-09222010-200746/ > E10/615/gm http://hdl.handle.net/2263/31278 http://upetd.up.ac.za/thesis/available/etd-09222010-200746/ en © 2010, 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
Steam system
Boiler efficiency
Pressure drop
Restructuring
Optimisation
Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title_full Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title_fullStr Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title_full_unstemmed Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title_short Steam system optimisation using process integration : a focus on boiler efficiency and pressure drop
title_sort steam system optimisation using process integration a focus on boiler efficiency and pressure drop
topic UCTD
Steam system
Boiler efficiency
Pressure drop
Restructuring
Optimisation
url http://hdl.handle.net/2263/31278
http://upetd.up.ac.za/thesis/available/etd-09222010-200746/