Energy optimization of wet air oxidation reactors with sub-millimeter bubble intensification

Liu, Xiemin; Wan, Jing; Zhu, Chengfeng; Zhang, Zheng; Zhang, Feng; Zhang, Zhibing

doi:10.1016/j.ces.2022.117864

Cited by 6 publications

(4 citation statements)

References 42 publications

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“…Liu et al designed a special sparger structure to generate sub-millimetre bubbles by ceramic membrane channels in a bubble column. [44] They found that a small Sauter mean diameter can be obtained with a high cross flow velocity, small superficial gas velocity, and low viscosity. Overall, manipulation of bubble size and acceleration of bubble coalescence and breakup are effective means of gas-liquid mass transfer augmentation.…”

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confidence: 99%

“…[51] Recently, researchers have paid attention to the performance of micro-bubble spargers. [44,[52][53][54] Han et al studied the performance of multi-channel ceramic membranes in a co-current bubble column with oxygen-water and oxygen-glycerine systems separately. [52,53] They discovered that the micro-bubbles generated by the multichannel ceramic membrane can produce higher gas holdup and volumetric mass transfer coefficient compared to the conventional sparger.…”

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confidence: 99%

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Gas holdup, bubble size distribution, and mass transfer in an airlift reactor with ceramic membrane and perforated plate distributor

et al. 2023

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The airlift reactor is one of the most commonly used gas–liquid two‐phase reactors in chemical and biological processes. The objective of this study is to generate different‐sized bubbles in an internal loop airlift reactor and characterize the behaviours of the bubbly flows. The bubble size, gas holdup, liquid circulation velocity, and the volumetric mass transfer coefficient of gas–liquid two‐phase co‐current flow in an internal loop airlift reactor equipped with a ceramic membrane module (CMM) and a perforated‐plate distributor (PPD) are measured. Experimental results show that CMM can generate small bubbles with Sauter mean diameter d32 less than 2.5 mm. As the liquid inlet velocity increases, the bubble size decreases and the gas holdup increases. In contrast, PPD can generate large bubbles with 4 mm < d32 < 10 mm. The bubble size and liquid circulation velocity increase as the superficial gas velocity increases. Multiscale bubbles with 0.5 mm < d32 < 10 mm can be generated by the CMM and PPD together. The volumetric mass transfer coefficient kLa of the multiscale bubbles is 0.033–0.062 s−1, while that of small bubbles is 0.011–0.057 s−1. Under the same flow rate of oxygen, the kLa of the multiscale bubbles increases by up to 160% in comparison to that of the small bubbles. Finally, empirical correlations for kLa are obtained.

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Gas holdup, bubble size distribution, and mass transfer in an airlift reactor with ceramic membrane and perforated plate distributor

et al. 2023

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“…For all these reasons, wet oxidation treatment facilities have been installed in about 200 industrial-scale plants worldwide to treat municipal and industrial sewage sludge [10][11][12]. Due to its exothermic nature, which is self-sustained from a certain organic matter content in the sewage sludge, energy recovery is one of the main technology characteristics [13,14].…”

Section: Introductionmentioning

confidence: 99%

Phosphorus Recovery from Sewage Sludge as Struvite

Cañas

Hermana²,

Garcı́a

2023

Water

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Environmental legislation on waste management coupled with the potential for nutrient recovery are key factors encouraging the use of advanced treatment technologies to manage biosolids waste. In this context, phosphorus recovery from sewage sludge treated by a wet oxidation (WO) process was carried out in this work. High organic matter (up to 85% in COD) and total solids content (up to 75%) removal values were achieved by the WO process at elevated temperature (up to 300 °C) and pressure (up to 200 bar) conditions. The liquid and solid fractions found in the oxidation process effluent contain high amounts of phosphorus that can be recovered. This research aims to maximize its recovery in both liquid and solid fractions. In the liquid effluent, phosphorus was recovered (up to 90 mg P/L) by chemical precipitation as struvite (MgNH4PO4∙6 H2O), a slow-release fertilizer. In this case, P recoveries greater than 95% were achieved. Additionally, the solid fraction, analyzed after filtration and drying (68 mg P/gsolid), was treated by acid leaching, obtaining up to 60% phosphorus recovery. All phosphorus extracted was in orthophosphate form.

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“…For all these reasons, wet oxidation has been installed in about 200 industrial-scale plants worldwide to treat municipal and industrial sewage sludge [7][8][9]. Due to its exothermic nature, self-sustained from a certain organic matter content, energy recovery is one of the main technology's characteristics [10,11].…”

Section: Introductionmentioning

confidence: 99%

Circular Economy Model Through Phosphorus Recovery to Obtain Struvite from Sewage Sludge

Cañas¹,

Hermana²,

Garcı́a³

2023

Preprint

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Environmental legislation on waste management coupled with the potential for nutrients recovery are key factors encouraging the use of advanced treatment technologies to manage biosolids waste. In this context, phosphorus recovery from a sewage sludge treated by a wet oxidation process was carried out. High organic matter (up to 85% in COD) and Total Solids content (up to 75%) removal values were achieved at elevated temperature (up to 300 ºC) and pressure (up to 200 bar) conditions. The liquid and solid fractions found in oxidation process effluent contain amounts of phosphorus that can be recovered. This research aims to maximize its valorization in both liquid and solid fractions. In the liquid effluent, phosphorus was recovered (up to 90 mg P L-1) by chemical precipitation as struvite (MgNH4PO4∙6 H2O), a slow-release fertilizer. In this case, P recoveries greater than 95% were achieved. Also, the solid fraction, analyzed after filtration and drying (68 mg P gsolid-1), was treated by acid leaching, to achieve up to 60% phosphorus recovery. All phosphorus extracted was in orthophosphate form.

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Energy optimization of wet air oxidation reactors with sub-millimeter bubble intensification

Cited by 6 publications

References 42 publications

Gas holdup, bubble size distribution, and mass transfer in an airlift reactor with ceramic membrane and perforated plate distributor

Gas holdup, bubble size distribution, and mass transfer in an airlift reactor with ceramic membrane and perforated plate distributor

Phosphorus Recovery from Sewage Sludge as Struvite

Circular Economy Model Through Phosphorus Recovery to Obtain Struvite from Sewage Sludge

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