Investigations of a continuous Poiseuille flow struvite seed crystallizer – Mixer performance and aggregate disruption by sonication

Burns, Max William; Marin, Leynard Natividad; Schneider, P.A.

doi:10.1016/j.cej.2016.03.061

Cited by 9 publications

(5 citation statements)

References 25 publications

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“…Tubular crystallizers (typically with an inner diameter of <10 cm and a length >1 m) are characterized by a high surface-to-volume ratio which facilitates faster heat transfer than in equivalent batch reactors. − …”

Section: Introductionmentioning

confidence: 99%

Crystal Engineering in Continuous Plug-Flow Crystallizers

Besenhard

Neugebauer

Scheibelhofer

et al. 2017

Crystal Growth & Design

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Size, shape, and polymorphic form are the critical attributes of crystalline particles and represent the major focus of today’s crystallization process design. This work demonstrates how crystal properties can be tuned efficiently in solution via a tubular crystallizer that facilitates rapid temperature cycling. Controlled crystal growth, dissolution, and secondary nucleation allow a precise control of the crystal size and shape distribution, as well as polymorphic composition. Tubular crystallizers utilizing segmented flow such as the one presented in our work can provide plug flow characteristics, fast heating and cooling, allowing for rapid changes of the supersaturation. This makes them superior for crystal engineering over common crystallizers. Characterization of particle transport, however, revealed that careful selection of process parameters, such as tubing diameter, flow rates, solvents, etc., is crucial to achieve the full benefits of such reactors.

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Section: Introductionmentioning

confidence: 99%

Crystal Engineering in Continuous Plug-Flow Crystallizers

Besenhard

Neugebauer

Scheibelhofer

et al. 2017

Crystal Growth & Design

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“…This situation could suggest that experimental identification of the solid phase is needed. For instance, previous works 3) Synthetic nutrient solution: 25 °C, pH (9.0), units (mol=L): Mg (3.5Â10 -3 ), N (7Â10 -3 ), P (7Â10 -3 ), Cl (7Â10 -3 ) 4) Raw wastewater adjusted with chemical reagents: 37 °C, pH (8.5), units (mol=L): Mg (1.00Â10 -1 ), N (1.00Â10 -1 ), P (1.00Â10 -1 ), Ca (5.29Â10 -4 ), K (5.50Â10 -2 ) À1.30, (5.61) have experimentally shown the presence of newberyite and possible bobbierite when the molar ratio Mg:N:P are 1.5:1:1 using X-ray diffraction (Burns et al 2016). Moreover, experimental data were collected from 2-L samples of anaerobic swine lagoon liquid, and elemental analysis was performed with Inductively Coupled Plasma spectrometry (Nelson et al 2003).…”

Section: Thermodynamic Software Applicationsmentioning

confidence: 99%

“…Figure 5 shows that induction time increases exponentially below SI ¼ 0.8, irrespective of the model parameters adopted. However, it has also been shown that scaling can occur in the continuous flow where induction time models predicted that it should not (Burns et al 2016). This was attributed to larger residence times in the slow moving viscous sub-layer.…”

Section: Induction Timementioning

confidence: 99%

“…While that work regresses kinetic parameters using extensive PSD and concentration data, it does find a high correlation between kinetic parameters and makes assumptions about the PSD below 2 μm. Future publications by our research group will detail nucleation, growth and aggregation kinetic parameter optimisations using experimental data from a Poiseuille flow reactor (Burns et al 2016).…”

Section: Struvite Aggregationmentioning

confidence: 99%

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A comparison of struvite precipitation thermodynamics and kinetics modelling techniques

Marin

Burns

Schneider

2023

Water Science and Technology

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Solution thermodynamics and kinetic modelling applied to struvite crystallisation–precipitation were reviewed from diverse references to determine proximity between predicted and cited experimental measurements. These simulations show the expected variability range of struvite saturation calculation when only limited solution compositional information is given, showing acceptable agreement between predicted and experimental struvite mass. This work also compares results from struvite crystallisation kinetic studies on liquid phase species depletion, crystallisation induction time, primary nucleation, secondary nucleation, crystal growth, and crystal aggregation. Large inconsistencies between reported kinetics were observed in many scenarios. Variations in species depletion models highlighted that they are only suitably applied to the specific system from which they were regressed. Spontaneous primary nucleation was predicted to occur in the range of SI = 0.237–0.8. Predicted primary nucleation rates vary over at least 10 orders of magnitude (depending on supersaturation) because of uncertainties in interfacial tension and maximum achievable nucleation rate. Secondary nucleation rates are more agreeable, varying over approximately two orders of magnitude. Growth rates varied over five orders of magnitude due to variations in experimental conditions. Aggregation rates are not thoroughly examined enough to make any inferences.

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“…Existing research studies have reported that adding seeding material to precipitation can control the crystallization rate and promote treatment effects ( Burns et al, 2016 ). Seeding material serves as a template through the reaction and its rough surface provides crystal growth sites ( Le Corre et al, 2007 ).…”

Section: Introductionmentioning

confidence: 99%

Biochar-seeded struvite precipitation for simultaneous nutrient recovery and chemical oxygen demand removal in leachate: From laboratory to pilot scale

et al. 2022

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Refuse transfer station (RTS) leachate treatment call for efficient methods to increase nutrient recovery (NH4+−N and PO43−−P) and chemical oxygen demand (COD) removal. In this study, the effects of various operational factors (seeding dose, pH, initial NH4+-N concentration, and reaction time) on biochar-seeded struvite precipitation were investigated at laboratory and pilot scales. Mealworm frass biochar (MFB) and corn stover biochar (CSB) were used as seeding materials to compare with traditional seed struvite. The maximum NH4+−N and PO43−−P recover efficiency of the MFB-seeded process reached 85.4 and 97.5%, higher than non-seeded (78.5 and 88.0%) and CSB-seeded (80.5 and 92.0%) processes and close to the struvite-seeded (84.5 and 95.1%) process. The MFB-seeded process also exhibited higher COD removal capacity (46.4%) compared to CSB-seeded (35.9%) and struvite-seeded (31.2%) processes and increased the average particle size of the struvite product from 33.7 to 70.2 μm for better sustained release. XRD, FT-IR, and SEM confirmed the orthorhombic crystal structure with organic matter attached to the struvite product. A pilot-scale test was further carried out in a custom-designed stirred tank reactor (20 L). In the pilot-scale test, the MFB-seeded process still spectacularly recovered 77.9% of NH4+−N and 96.1% of PO43−−P with 42.1% COD removal, which was slightly lower than the laboratory test due to insufficient and uniform agitation. On the whole, MFB-seeded struvite precipitation is considered to be a promising pretreatment method for rural RTS leachate.

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Investigations of a continuous Poiseuille flow struvite seed crystallizer – Mixer performance and aggregate disruption by sonication

Cited by 9 publications

References 25 publications

Crystal Engineering in Continuous Plug-Flow Crystallizers

Crystal Engineering in Continuous Plug-Flow Crystallizers

A comparison of struvite precipitation thermodynamics and kinetics modelling techniques

Biochar-seeded struvite precipitation for simultaneous nutrient recovery and chemical oxygen demand removal in leachate: From laboratory to pilot scale

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