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Simultaneous Optimization of Water and Energy in Integrated Water and Membrane Networks
Published in Iqbal M. Mujtaba, Thokozani Majozi, Mutiu Kolade Amosa, Water Management, 2018
Esther Buabeng-Baidoo, Thokozani Majozi
There are two major approaches adopted in addressing water network synthesis: insight-based techniques and mathematical model–based optimization methods. Insight-based techniques involve the water pinch analysis, which is a graphical method based on the concept of a limiting water profile that is the most contaminated water that can be fed into a particular operation. This method was first proposed by Wang and Smith.12 Hallale13 then proposed a graphical method based on non-mass transfer operations with single contaminants. Recent studies have extended water pinch analysis to algebraic methods, primarily water cascade analysis.14,15 The water pinch method proves unsuccessful for complex problems involving multiple contaminants16 and various topological constraints.4 The computation burden of this method is, however, lower than that experienced by mathematical model–based optimization methods.
Water Optimization in Process Industries
Published in Prasenjit Mondal, Ajay K. Dalai, Sustainable Utilization of Natural Resources, 2017
Elvis Ahmetović, Ignacio E. Grossmann, Zdravko Kravanja, Nidret Ibrić
This section presents a brief description of systematic methods based on water-pinch analysis and mathematical programming, which are used for water network design. Water-pinch technology/analysis (Wang and Smith 1994a,b; Wang and Smith 1995) is a graphical method, which represents an extension of pinch analysis for heat integration (Linnhoff and Hindmarsh 1983). It consists of two phases, namely, targeting and design. Assuming a single contaminant, the main goal of the targeting phase is to determine the minimum freshwater consumption (maximum water reuse) (Doyle and Smith 1997) before a water network design, while within the design phase, a water network is constructed, satisfying the minimum freshwater consumption. Also, water-targeting models for multiple contaminants have been proposed, based on mathematical programming, in order to perform simultaneous flow-sheet optimization (Yang and Grossmann 2013).
A novel approach to integration of hot oil and combined heat and power systems through Pinch technology and mathematical programming
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Gholamreza Shahidian Akbar, Hesamoddin Salarian, Abtin Ataei
By regeneration of wastewater in water systems (Wang and Smith 1994), the flow rate of freshwater and operating cost of the system may be decreased (Mann and Liu 1999). The wastewater regeneration method in water Pinch analysis was first presented by Wang and Smith (1994). That technique was developed by Ataei et al. (2009) who combined it with thermal Pinch analysis to be applicable in the design and optimization of cooling water systems (Ataei et al. 2009). In this study, Ataei et al. method (2009) for cooling water systems has been expanded to hot oil systems to reduce temperature of the return hot oil sent to the heating section of a CHP system. That may make higher temperature waste heat available for more power generation by the bottoming cycle. It should be noted that even by utilizing a WHR2 as a local hot oil regenerator, the total heat load of the hot oil system will not be decreased. However, some of the hot oil generation load is taken by the WHR2 at a lower temperate and therefore the load of WHR1 is decreased.
Chemical conditioning of drinking water to reduce Ca precipitation using water pinch methodology for sources with different Ca and Mg hardness composition
Published in Urban Water Journal, 2022
Juan Ernesto Ramírez Juárez, Alba Nélida García Beltrán, Anuard Isaac Pacheco-Guerrero, Ángel Alfonso Villalobos de Alba
The network construction for Ca2+ reduction concentration is carried on through the NNA previously described. This network must meet with the amount of 134.7 m3/h of freshwater obtained through water pinch analysis, Figure 3(a). Demand D1 requires 20 mg/L of Ca2+ at 121.8 m3/h. The nearest neighbour Sk and S(k+1) are therefore S0 (freshwater) and S1, respectively. Equations (3) and (4) give FS0,D1 + FS1,D1 = 121.8 and FS0,D1(0) + FS1,D1(30) = 121.8(20), which may be solved to obtain FS0,D1 = 40.6 m3/h and FS1,D1 = 81.2 m3/h. Both these flow rates are less than the available amounts (130 and 121.5 m3/h, respectively), and hence the entire demand for D1 is fulfilled by sources S0 and S1. The flow rates now available for S0 and S1 are 94.1 and 40.3 m3/h, respectively. Demand D2 target is 25 mg/L of Ca2+ at 216.6 m3/h. The nearest neighbours are S0 and S1, nonetheless are not enough to cover the flow rate. Then, the nearest neighbour is used and corresponds to S2. The procedure to resolve this is to use the residual of S1 and resolve the Equations (3) and (4) with S0 and S2 as Ss and St, respectively. The equations are established as follows: FS0,D2 + FS2,D2 = 216.6–40.3 and FS0,D2(0) + FS2,D2(38.1) = 216.6(25) – 40.3(30), resolving S0 and S2 are 65.8 and 110.5 m3/h, respectively, which are lower than the available flow rates. Refresh flow rates for S0 and S2 are obtained at 28.3 and 106.8 m3/h, respectively. The demand D3 objective is 35 mg/L Ca2+ at 203 m3/h; total residual flow rate of freshwater is used to fit with total freshwater added to the system, as well as the total S2 residual flow rate is incorporated. Then, S3 and S4 are used as Ss and St, respectively, to fulfil the demand. Equations (4) and (5) give FS3,D3 + FS4,D3 = 203–28.3 – 106.8 and FS3,D3(43) + FS4,D3(48.1) = 203(35)-28.3(0)-106.8(38.1), respectively. The solution to the equations gives 45.1 and 22.9 m3/h for S3 and S4, respectively, to fulfil demand D3. The residual flow rates are S3 = 14.9 m3/h and S4 = 130.1 m3/h. Both balance of Mg2+ concentration and Ca/Mg ratio obtained in accord with the flow rates resolved are presented in Figure 3(a).