Water softening by induced crystallization in fluidized bed

Chen, Yuefang; Fan, Ren‐Hao; An, Danfeng; Cheng, Yuanbing; Tan, Hazel L.

doi:10.1016/j.jes.2016.08.014

Cited by 29 publications

(10 citation statements)

References 27 publications

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“…Chen et al (2016) applied the Amsterdam reactor in recirculating cooling water softening, and analyzed the influence factors, including the pH, height of the fluid bed, particle size, influent flow, and reflux ratio (ratio of the part of the effluent flow refluxed to influent flow and influent flow) on hardness removal. The effluent concentration of Ca 2+ reached a removal efficiency of 86.6% [11]. Hu et al (2017) studied the influence of factors including superficial velocity ( SV ), particle size ( L 0 ), and supersaturation ( S ) on the pellet growth rate of CaCO 3 .…”

Section: Introductionmentioning

confidence: 99%

Full-Scale Experimental Study of Groundwater Softening in a Circulating Pellet Fluidized Reactor

Zhi

Tang

2018

IJERPH

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The softening effect of a new type of circulating pellet fluidized bed (CPFB) reactor on groundwater was studied through a full-scale experiment. The operation of the CPFB reactor in the second water plant in Chang’an District in Xi’an China was monitored for one year, and the results were compared with those for the Amsterdam reactor in The Netherlands. The removal efficiency of Ca2+ in the CPFB reactor reached 90%; the removal rate of total hardness was higher than 60%; effluent pH was 9.5–9.8; the turbidity of the effluent and the turbidity after boiling were lower than 1.0 NTU; the unit cost was less than €0.064 per m3; and the softened effluent was stable. The pellets in the CPFB reactor were circulated, providing higher crystallization efficiency. The diameter of the discharged pellets reached between 3–5 mm, and the fluidized area height of the CPFB reactor was 4 m. The performance parameters of the CFPB reactor were optimized.

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Section: Introductionmentioning

confidence: 99%

Full-Scale Experimental Study of Groundwater Softening in a Circulating Pellet Fluidized Reactor

Zhi

Tang

2018

IJERPH

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“…Figure 6 shows a scanning electron microscopy (SEM) image of the particles discharged from the system after about 20 days of equipment operation, and their size is usually approximately 1.0–3.0 mm at the time of discharge [21]. Via testing and analysis, the content of CaO in the particles generated from the CPFBs in the Dingzhou Power Plant was found to be 51.10%, as shown in Table 2.…”

Section: Resultsmentioning

confidence: 99%

Application of Chemical Crystallization Circulating Pellet Fluidized Beds for Softening and Saving Circulating Water in Thermal Power Plants

Wang

et al. 2019

IJERPH

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The circulating pellet fluidized bed (CPFB) softening method is a highly efficient and environmentally friendly softening technology that can be used to reduce water hardness during the pretreatment process of circulating water in thermal power plants. The performance of chemical crystallization CPFB reactors was tested for increasing the concentration ratio and softening the circulating water in a thermal power plant in Dingzhou, Hebei. The results show that usage of CPFB reactors removed water hardness and Ca2+ ions with efficiencies exceeding 60% and 90%, respectively. The size of the particles discharged from the reactors was approximately 1–3 mm, and the content of CaO in these particles was found to be greater than 50%. All the discharged particles were reused in the desulfurization system in the power plant. The operational cost of the CPFB system is US$0.074 per cubic meter of water. After adopting the proposed CPFB softening method in the Dingzhou Power Plant, the concentration ratio of the circulation cooling water was increased from 4.5 to more than 9. In addition, the amount of replenished water and sewage discharge were both reduced by 150 m3/h, and the amount of scale inhibitor used in the system was reduced by more than 30%. These improvements contribute to approximately US$200,000 in annual savings in the power plant. In summary, the CPFB softening method demonstrated a high hardness removal rate, strong economic benefits, and remarkable environmental and social benefits. Therefore, this method seems ideal for softening replenished circulating cooling water, increasing the concentration ratio of the water and achieving zero liquid discharge (ZLD) in thermal power plants.

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“…To avoid these problems and to satisfy the continuous need to have soft or at least moderately hard water for drinking, domestic and industrial uses, a pretreatment process for primary water resources is an essential issue. To achieve this purpose conventional and modern methods are adapted, starting from the use of lime and soda ash for removal of hardness in water treatment plants through precipitation (Burakov et al., 2018; Labban, Liu, & Chong, 2017; Nayar et al., 2015), to ion exchange process using ion exchange resins (Segev, Hasson, & Semiat, 2011), electro deionization process (Park, Song, Yeon, & Moon, 2007), electromembrane processes (Park et al, 2007; Seo et al., 2010), capacitive deionization (Lee & Choi, 2012), membrane and fluidized pellet reactor (Chen, Fan, An, Cheng, & Tan, 2016), fluidized‐bed homogeneous crystallization (FBHC) (Chen, Shih, & Huang, 2015), and adsorption (Pastrana‐Martínez, López‐Ramón, Fontecha‐Cámara, & Moreno‐Castilla, 2010) have been studied for the removal of a wide variety of ionic and molecular species from various water streams, including those responsible for hardness (e.g. Ca(II) and Mg(II) cations).…”

Section: Introductionmentioning

confidence: 99%

Microwave‐enforced green synthesis of novel magnetic nano composite adsorbents based on functionalization of wood sawdust for fast removal of calcium hardness from water samples

Soliman

Ahmed

Fadl

2020

Water Environment Research

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Developing new generation of adsorbents for water treatment to reduce calcium hardness and producing high quality water is important and continuous trend. This manuscript is devoted with this direction. Thus, two novel magnetic nanocomposite adsorbents were synthesized by covalently binding of tartaric acid (TA) and citric acid (CA) to wood sawdust coated magnetic nanoparticles (WSD@Fe 3 O 4 NPs) using green microwave solvent-less technique. The adsorbents thus prepared WSD@Fe 3 O 4 NPs-TA and WSD@Fe 3 O 4 NPs-CA were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Preliminary batch experiments were performed to evaluate percentage of Ca(II) adsorbed by the bare WSD@Fe 3 O 4 NPs and its functionalized forms by TA and CA, as a function of pH (initial concentration 80 mg/L), indicated 59.5%, 84.70%, and 99.29%, respectively, at pH 7 as optimal value. To attain maximum adsorption capacity, effect of adsorbent dosage and contact time were also optimized for the two modified adsorbents. Accordingly, Ca(II) adsorption capacity was determined to be 18.4 mg/g as exhibited by WSD@ Fe 3 O 4 NPs-TA. However, WSD@Fe 3 O 4 NPs-CA showed higher capacity value recorded to be 27.2 mg/g. The novel adsorbents were successfully applied for fast reduction of calcium hardness from real water samples, during 15-20 min and via two consecutive in situ batch operations.

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Water softening by induced crystallization in fluidized bed

Cited by 29 publications

References 27 publications

Full-Scale Experimental Study of Groundwater Softening in a Circulating Pellet Fluidized Reactor

Full-Scale Experimental Study of Groundwater Softening in a Circulating Pellet Fluidized Reactor

Application of Chemical Crystallization Circulating Pellet Fluidized Beds for Softening and Saving Circulating Water in Thermal Power Plants

Microwave‐enforced green synthesis of novel magnetic nano composite adsorbents based on functionalization of wood sawdust for fast removal of calcium hardness from water samples

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