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Conceptual insights to debottleneck the Network Pinch in heat-integrated crude oil distillation systems without topology modifications

Gadalla, Mamdouh A.; Abdelaziz, Omar Y. LU and Ashour, Fatma H. (2016) In Energy Conversion and Management 126. p.329-341
Abstract
Heat exchanger network pinch sets the limitations of heat recovery for existing network topologies. Improving the heat recovery within a pinched-network is independent of the areas of individual exchangers present in the network, rather the topology of the network must be altered. Such a change in the topology can be very capital intensive and in many cases seems not easy to implement. This research aims to overcome the Network Pinch through proposing process operation changes, avoiding network topology alterations; hence, debottlenecks the heat-integrated systems towards further energy savings beyond the maximum heat recovery limitations. A new graphical representation is recently proposed to simulate existing preheat trains/networks with... (More)
Heat exchanger network pinch sets the limitations of heat recovery for existing network topologies. Improving the heat recovery within a pinched-network is independent of the areas of individual exchangers present in the network, rather the topology of the network must be altered. Such a change in the topology can be very capital intensive and in many cases seems not easy to implement. This research aims to overcome the Network Pinch through proposing process operation changes, avoiding network topology alterations; hence, debottlenecks the heat-integrated systems towards further energy savings beyond the maximum heat recovery limitations. A new graphical representation is recently proposed to simulate existing preheat trains/networks with all energy equipment. The recent graphical representation is employed in this work to identify the pinching matches that limit heat recovery. Therefore, such graphs are key tools to identify potential process changes by which the Network Pinch is overcome. New graphs are constructed involving hot stream temperatures against cold stream temperatures. Existing exchangers are described by straight lines, with slopes related to flows of process streams and heat capacities. Exchanger matches touching the line where hot outlet stream temperature equals cold inlet stream temperature are pinching matches; this condition corresponds to absolute maximum heat recovery (ΔT = 0). Potential process changes within a distillation unit are identified to relax the Network Pinch and further heat recovery is maximised. The slope of such an exchanger match is decreased or the location of the pinching match is altered keeping the same slope. These changes are translated into process changes within the crude oil distillation unit. Accordingly, the process changes are determined based on which match is pinched besides its location within the network. An illustrative example shows that process changes overcome the Network Pinch and energy recovery is increased by 14% beyond the maximum level achieved for the existing process conditions. Capital investments imposed are minor compared with substantial energy cost savings. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Network Pinch; Energy efficiency; Retrofit; Heat exchanger network; Crude distillation unit; Process integration
in
Energy Conversion and Management
volume
126
pages
13 pages
publisher
Elsevier
external identifiers
  • Scopus:84981524635
ISSN
0196-8904
DOI
10.1016/j.enconman.2016.08.011
language
English
LU publication?
yes
id
edbae375-b6c1-41fb-b0ed-8839ae376733
date added to LUP
2016-08-23 10:59:14
date last changed
2016-10-25 13:45:02
@misc{edbae375-b6c1-41fb-b0ed-8839ae376733,
  abstract     = {Heat exchanger network pinch sets the limitations of heat recovery for existing network topologies. Improving the heat recovery within a pinched-network is independent of the areas of individual exchangers present in the network, rather the topology of the network must be altered. Such a change in the topology can be very capital intensive and in many cases seems not easy to implement. This research aims to overcome the Network Pinch through proposing process operation changes, avoiding network topology alterations; hence, debottlenecks the heat-integrated systems towards further energy savings beyond the maximum heat recovery limitations. A new graphical representation is recently proposed to simulate existing preheat trains/networks with all energy equipment. The recent graphical representation is employed in this work to identify the pinching matches that limit heat recovery. Therefore, such graphs are key tools to identify potential process changes by which the Network Pinch is overcome. New graphs are constructed involving hot stream temperatures against cold stream temperatures. Existing exchangers are described by straight lines, with slopes related to flows of process streams and heat capacities. Exchanger matches touching the line where hot outlet stream temperature equals cold inlet stream temperature are pinching matches; this condition corresponds to absolute maximum heat recovery (ΔT = 0). Potential process changes within a distillation unit are identified to relax the Network Pinch and further heat recovery is maximised. The slope of such an exchanger match is decreased or the location of the pinching match is altered keeping the same slope. These changes are translated into process changes within the crude oil distillation unit. Accordingly, the process changes are determined based on which match is pinched besides its location within the network. An illustrative example shows that process changes overcome the Network Pinch and energy recovery is increased by 14% beyond the maximum level achieved for the existing process conditions. Capital investments imposed are minor compared with substantial energy cost savings.},
  author       = {Gadalla, Mamdouh A. and Abdelaziz, Omar Y. and Ashour, Fatma H. },
  issn         = {0196-8904},
  keyword      = {Network Pinch; Energy efficiency; Retrofit; Heat exchanger network; Crude distillation unit; Process integration},
  language     = {eng},
  month        = {10},
  pages        = {329--341},
  publisher    = {ARRAY(0xab95180)},
  series       = {Energy Conversion and Management},
  title        = {Conceptual insights to debottleneck the Network Pinch in heat-integrated crude oil distillation systems without topology modifications},
  url          = {http://dx.doi.org/10.1016/j.enconman.2016.08.011},
  volume       = {126},
  year         = {2016},
}