Energy consumption to achieve macromixing revisited

Liné, Alain

doi:10.1016/j.cherd.2015.11.016

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…Because the CIST has a non-standard geometry, scale-up has to be performed on the basis of the reproduction of the total mixing energy (J/ kg) 47,48 at both bench and industrial scales. Machado and Kresta 30 provide a procedure showing how to mimic conditions from an industrial-scale pipeline in the CIST.…”

Section: Methodsmentioning

confidence: 99%

Reduce Overdosing Effects in Chemical Demulsifier Applications by Increasing Mixing Energy and Decreasing Injection Concentration

et al. 2016

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It has been known for years that the performance of a demulsifier in diluted bitumen dewatering improves up to a certain demulsifier bulk concentration. After this limit, the water removal deteriorates. This phenomenon is called overdosing. In this paper, the effects of mixing energy and demulsifier injection concentration on water removal are studied in systems with a high bulk demulsifier concentration. The experiments were conducted in a confined impeller stirred tank (CIST), which provides well-controlled mixing conditions with more uniform turbulence and flow than a conventional stirred tank. The results show that an increase in mixing energy and pre-dilution of the demulsifier may be able to overcome overdosing effects at a high bulk (mean) concentration. If the mixing conditions are well-designed, high local demulsifier concentrations at the feed point are avoided and the demulsifier can perform well, even at high bulk concentrations. The best demulsifier performance in an overdosed system was obtained with a combination of high mixing energy and low injection concentration, where over 80% of the water content was separated at a demulsifier bulk concentration that showed severe overdosing behavior at poor mixing conditions.

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Section: Methodsmentioning

confidence: 99%

Reduce Overdosing Effects in Chemical Demulsifier Applications by Increasing Mixing Energy and Decreasing Injection Concentration

et al. 2016

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“…ε imp and t mix were lumped into a single parameter, the mixing energy J (= ε imp ×t mix ). 44,47 Instead of repeating the complete Box−Behnken factorial design, a two-level factorial design was conducted in which the variables X BC , X IC , and X J had two values: −1 and +1, as shown in Table 1. A full factorial design of eight experiments was conducted.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Demulsifier Performance in Diluted Bitumen Dewatering: Effects of Mixing and Demulsifier Dosage

et al. 2016

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Mixing conditions were explored as a possible avenue for improvement of demulsifier performance in the solventdiluted bitumen dewatering process. The effects of demulsifier bulk concentration, demulsifier injection concentration, and mixing energy on water and solids removal from the oil phase were tested. All of the experiments were carried out in a confined impeller stirred tank, which provides well-characterized mixing conditions and relatively uniform flow and turbulence. Results showed that lowering the injection concentration and increasing the mixing energy both improve demulsifier performance, allowing a 50% drop in the bulk concentration of demulsifier. This result agrees well with an earlier study by Laplante et al. 1 in which a different demulsifier was investigated. In that study, it was shown that the product of mixing time and energy dissipation rate at the feed point (the mixing energy = J) provides an alternate mixing variable.

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“…23,24 Cumulative mixing energy has been shown to work as a scaling variable where geometric similarity is not possible or practical, contingent on maintaining fully turbulent flow in the test vessel. 27,28 This work seeks to extend the knowledge of mixing effects into poorer-processing froth by studying the water content as it changes over the full height of the vessel during settling. The effects of demulsifier bulk concentration, demulsifier injection concentration, and mixing energy were assessed.…”

Section: Introductionmentioning

confidence: 99%

Dewatering of Poor-Quality Bitumen Froth: Induction Time and Mixing Effects

Saraka

Machado

et al. 2018

Energy Fuels

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The impact of mixing conditions on the removal of water and solids from high-water, poor-quality bitumen froth was explored. Naphtha diluent and a demulsifier were added to improve removal of water and solids from bitumen froth. The mixing and subsequent settling of this system were carried out in the confined-impeller stirred tank, a lab-scale mixing test vessel with well-characterized, relatively uniform mixing conditions. A protocol for finding the proper demulsifier dosage at which to study mixing effects was applied successfully. High mixing energy J and the predilution of demulsifier (characterized by its injection concentration IC) improved dewatering and solids removal performance, agreeing with earlier studies in diluted bitumen and bitumen froth of higher quality (Laplante et al. Fuel Process. Technol. 2015, 138, 361–367; Arora, N. Mechanisms of Aggregation and Separation of Water and Solids from Bitumen Froth Using Cluster Size Distribution, 2016). An unexpected finding was that dewatering was significantly delayed in poor-quality froth: it was not detectable until up to 45 min in some cases. This induction time was replicated and was clearly impacted by changes in the mixing conditions.

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Energy consumption to achieve macromixing revisited

Cited by 7 publications

References 11 publications

Reduce Overdosing Effects in Chemical Demulsifier Applications by Increasing Mixing Energy and Decreasing Injection Concentration

Reduce Overdosing Effects in Chemical Demulsifier Applications by Increasing Mixing Energy and Decreasing Injection Concentration

Demulsifier Performance in Diluted Bitumen Dewatering: Effects of Mixing and Demulsifier Dosage

Dewatering of Poor-Quality Bitumen Froth: Induction Time and Mixing Effects

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