Heat-integrated water network

Bogataj, M. and Bagajewicz, M.J. (2008) Synthesis of non-isothermal heat integrated water networks in chemical processes. Computers and Chemical Engineering, 32 (12), 3130-3142. 

Sharma, S. and Rangaiah, G.P. (2014) Multi-objective Optimization of Heat Integrated Water Networks in Petroleum Refineries. Proceedings of the 24th European Symposium on Computer Aided Process Engineering, Budapest, Hungary, pp. 1531-1536. 

In the chemical industry, water is extensively used as a reactant, separation solvent and heating/cooling medium, and therefore the water integration is required due to both economic and environmental reasons. In Chapter 12, Sharma and Rangaiah present a mathematical model that can be used for grassroots and retrofit design of water networks. 

Linnhoff proposed the heat integration and synthesis of heat exchanger networks (HENs) [52], It is well known as pinch technology. The graphical and numerical techniques have been well developed [55], This technique has been extended for mass-exchange networks like water networks and hydrogen networks [52]. These are not considered here. 

Finally, a new concern has focused the attention of many researchers— water consumption. The main problem with water consumption is that, in general, the cost is low and thus the economic evaluation does not provide water consumption minimization apart from the sequential approach consisting of the development of water networks for the treatment and reuse of water after process design [24]. Currently, a simultaneous process design with heat and water integration is being developed based on the targeting methods [25]. 

More detailed heat integration with different utilities (cold water, refrigerator, steam), restrictions and forbidden matches was carried out simultaneously with the synthesis of the reactor/separator/HEN network. Reactors were modelled as adiabatic reactors due to practical constraints. 

III. Heat/Process Integration Study Pinch analysis is well established for finding optimal utilities, heat transfer area, optimal fresh water consumption, minimum cooling water demand, reduced emissions targets and so on (Smith, 2005 Kemp, 2007). One application of pinch analysis to retrofitting the heat exchanger network of a crude... 

To obtain maximum pipeline integrity and match joint life to pipe material life, welded construction, free of mechanical connections and involving no intermediary materials such as seals or adhesives, is the preference of pipeline engineers. The ability to construct an all-welded pipeline network, using heat fusion, is one of the major advantages offered by PE to gas and water distribution applications. 

Sub-networks Identification A designed HEN can be divided into a number of independent sub-networks based on the structure of the HEN. A sub-network can be defined as a set of process streams and heat exchangers that are integrated to each other to form an independent network. Each sub-network in the considered HEN should be treated separately in the next controllability assessment steps. Fig. 8 shows an example of a HEN consists of three hot streams and four cold streams where the coolers and heaters use the same cooling and heating utility respectively, such as cooling water for coolers and HP steam for heaters. The figure shows three independent sub-networks as follow ... 

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