In-line Static Mixers Research Articles

Polymer Solution Preparation, Quality Control, and Produced Fluid Analysis at Milne Point

Summary This paper focuses on solution preparation and quality control activities associated with the Milne Point polymer flood on the North Slope of Alaska. This project uses 10 different polymer injection locations with a variety of skid types and configurations, which had a notable impact on polymer quality control and dissolution operations. Compared with bulk 500-kg to 750-kg polymer bags, silos greatly improved the storage capacity and increased the overall quality of the polymer solutions. Silos required less physical effort when transferring polymer. Polymer hydration skids that were made in-house by the polymer supplier were more reliable and experienced fewer polymer solution quality and startup issues than those that were outsourced. These in-house skids also used a uniform programming software that made it relatively easy to train the operators on new hydration skids. For pumping polymer mother solution, triplex pumps provided the best runtime and were most maintenance-friendly, compared with diaphragm or triple screw pumps. Because of the soluble iron present in the polymer makeup water, nitrogen blanketing was preferred to minimize corrosion and oxidative degradation. Inline static mixers were ineffective in mixing mother solution with dilution water when the mixing occurred close to the wellhead. Mixing the two streams too close to the wellhead led to substantial variations in wellhead viscosity measurements. Dedicating individual pumps for injection into a given well provided desirable flexibility in controlling rates and concentrations of polymer for the well. Monitoring produced salinity and polymer concentration provided useful insights about improved sweep and polymer retention associated with the polymer flood. The observed field behavior was consistent with laboratory studies, indicating a “tailing” phenomenon associated with polymer retention at Milne Point.

The Use of A Static Mixer for The Coagulation Unit in The Duren Seribu II Water Treatment Plant

In the drinking water treatment plant involves a significant component i.e., coagulation, which distributed coagulants vastly and equally through rapid stirring for destabilizing colloids and suspended particles in the raw water. In water treatment plants, coagulation units are often classified into mechanical and hydraulic coagulation. This study aimed to discover the use of and in-line static mixers as coagulation in designing the Duren Seribu II Drinking Water Treatment Plant (WTP). The design criteria for coagulation unit in Duren Seribu II WTP was determined by comparing several data obtained from literature studies and evaluation of the existing conditions of Duren Seribu I WTP. Duren Seribu I WTP was evaluated by direct measurement in the field. From the results of data analysis, the design criteria appropriate for Duren Seribu II WTP, the G value is 2078.07 sec-1, the detention time (td) is 4 sec, and the G.td value is 8352.19.

A PBM-Based Procedure for the CFD Simulation of Gas–Liquid Mixing with Compact Inline Static Mixers in Pipelines

A compact static mixer for gas–liquid dispersion in pipelines is studied in this paper with a Reynolds averaged two fluid model approach. A procedure based on the lumped parameter solution of a population balance model is applied to obtain the bubble Sauter mean diameter needed to model the interphase forces. The gas distribution in the pipe is analyzed in two different operative conditions and the efficiency of the static mixer is assessed in terms of the gas homogeneity in the pipe section, with low coefficients of variations being obtained. A computational model to obtain the volumetric mass transfer coefficient, kLa, developed for partially segregated systems is applied finding kLa values comparable to those typically obtained with other static mixers. The proposed computational model allows us to locally analyze the oxygen transfer rate by observing the limitations due to gas accumulation behind the body of the static mixer, which leads to the local depletion of the driving force. Geometrical optimization of the static element is proposed, based on the analysis of gas–liquid fluid dynamics and of the interphase mass transfer phenomena.

ANALISIS MULTI KRITERIA DALAM PEMILIHAN UNIT PENGOLAHAN AIR IPA CIAWI, KECAMATAN MEGAMENDUNG, KABUPATEN BOGOR

To increase service coverage and meet the increasing demand for drinking water, PDAM Tirta Kahuripan plans to build a Ciawi WTP in Megamendung District with a processing capacity of 165 L/second using the Sukabirus River as a raw water source. The purpose of this study was to determine the processing units in the design of the Ciawi WTP using multi-criteria analysis. Based on the results of the analysis of raw water quality, there were several parameters that do not meet the drinking water quality standards according to the Minister of Health Regulation No. 492 of 2010 and PPRI No. 82 of 2001, namely turbidity, Fecal coliform, total coliform, TSS, BOD, COD, and DO. There were three alternative processing circuits used. Alternative I consists of intake, hydraulic coagulation, up-down flow hydraulic flocculation, plate settler sedimentation, rapid sand filtration, disinfection, and reservoir. Alternative II consists of intake, hydraulic coagulation, vertical-shaft paddle wheel mechanical flocculation, tube settler sedimentation, rapid sand filtration, disinfection, and reservoir. Alternative III consists of intake, in-line static mixers coagulation, horizontal-shaft paddle wheel mechanical flocculation, plate settler sedimentation, rapid sand filtration, disinfection, and reservoir. There are other factors that must be considered in the selection of treatment units, namely contaminant removal, reliability, flexibility, construction, land requirements, ease of operation, maintenance, cost, and environmental compatibility. Based on multi-criteria analysis, the percentage of suitability for alternative I is 78%, Alternative II is 63%, and Alternative III is 48%. From this assessment, it can be said that alternative I is the best alternative.

Impact of preflocculation on scroll decanter centrifuge separation performance

AbstractIndustrial scroll decanter centrifuge (SDC) separation of the solids in fluid fine tailings (FFT) which have particles 10 μm and smaller in size require flocculant addition. Accordingly, the mechanism in the centrifuge is flocculation of the fine solid particles followed by sedimentation. Thus, feeding preflocculated material obviates the flocculation step inside the SDC resulting in improved process efficiency by reducing the power consumption and increasing the throughput capacity of each SDC. This work evaluated the separation performance of the SDC using inline static mixers to preflocculate oil sands FFT containing solids, 90 mass% of which are < 9 μm in size. The minimum G‐forces required to achieve the industry benchmarks of < 1 mass% solids in the centrate water and > 97 % fines capture rate were 750 G without preflocculation and 400 G with preflocculation. Since power consumption by the SDC, as expected, was directly proportional to the G‐force, the savings in power due to preflocculation amounted to 47 %. Preflocculation increased SDC throughput capacity by up to 50 %. Operating at lower G‐force has the additional benefits of protecting the high‐capital‐cost SDC machine and reducing ambient noise levels.

The assembly and use of continuous flow systems for chemical synthesis.

The adoption of and opportunities in continuous flow synthesis ('flow chemistry') have increased significantly over the past several years. Continuous flow systems provide improved reaction safety and accelerated reaction kinetics, and have synthesised several active pharmaceutical ingredients in automated reconfigurable systems. Although continuous flow platforms are commercially available, systems constructed 'in-lab' provide researchers with a flexible, versatile, and cost-effective alternative. Herein, we describe the assembly and use of a modular continuous flow apparatus from readily available and affordable parts in as little as 30 min. Once assembled, the synthesis of a sulfonamide by reacting 4-chlorobenzenesulfonyl chloride with dibenzylamine in a single reactor coil with an in-line quench is presented. This example reaction offers the opportunity to learn several important skills including reactor construction, charging of a back-pressure regulator, assembly of stainless-steel syringes, assembly of a continuous flow system with multiple junctions, and yield determination. From our extensive experience of single-step and multistep continuous flow synthesis, we also describe solutions to commonly encountered technical problems such as precipitation of solids ('clogging') and reactor failure. Following this protocol, a nonspecialist can assemble a continuous flow system from reactor coils, syringes, pumps, in-line liquid-liquid separators, drying columns, back-pressure regulators, static mixers, and packed-bed reactors.

Assessing the potential of using chaotic advection flow for thermal food processing in heating tubes

Most food materials tend to be viscous and in general flow in the laminar regime. In continuous food sterilisation, the non-uniform velocity profile which characterises viscous flow coupled with a non-uniform temperature distribution result in a wide variation of product sterility and nutritional quality across the tube. The challenge is to be able to sterilise the fastest parts in the core region of the tube without over-processing too much the slowest parts near the wall. Chaotic advection is an alternative to turbulence, and uses the stretching and folding property of chaotic flows to promote fluid mixing at low Reynolds numbers. The use of inline static mixers or vortex generators to promote radial mixing and, thus, heat transfer and temperature uniformity, generates large pressure drops but more importantly these devices are unhygienic. We use a validated Computational Fluid Dynamics (CFD) model to show that mechanical vibration is an effective source of chaotic advection. The superimposition of a transverse harmonic motion on the flow of a single-phase viscous fluid in a heating tube, leads to large improvements in thermal processing uniformity and efficiency compared with a conventional process with or without an inline static mixer fitted. Results show that high levels of sterility, processing uniformity and product quality can be achieved in relatively short heating tubes, thus, potentially obviating the need for a holding stage.

Scaling inline static mixers for flocculation of oil sand mature fine tailings

Operations to reclaim mature fine tailings (MFT) ponds involve flocculation using high‐molecular‐weight polymers, for which inline static mixers are suited. Three different commercial static mixers were utilized to determine mixing parameters corresponding to optimal dewatering performance of flocculated MFT. MFT was treated with polymer solution under different mixing conditions. The dewatering rates passed through a peak with increasing mean velocity, V and Reynolds number, Re of the fluid. The greater the number of mixer elements, the lower the V and Re at which the peak dewatering rate occurred. Mixing parameters such as G‐value, residence time, and mixing energy dissipation rate of the most rapidly dewatering flocculated MFT were dependent on mixer type and setup. In contrast, peak dewatering rates converged when scaled with respect to specific mixing energy, E, demonstrating that E is a suitable scale‐up parameter for inline static mixing to produce optimally dewatering MFT. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4402–4411, 2015

Review of Coagulation’s Rapid Mixing for NOM Removal

This review focuses on rapid mixing in the coagulation process for improved natural organic matter (NOM) removal in water treatment. Rapid mixing aims to instantly and efficiently disperse coagulant species into raw water, before flocculation, sedimentation, and filtration processes. Mechanical mixing with a longer retention time cannot guarantee an instantaneous and uniform coagulant dispersion. For this reason, the so-called pump diffusion mixer (PDM) has been proposed. Using various rapid mixing devices to test the sedimentation performance, it is showed that in-line hydraulic jet and static mixers are able to achieve performance equivalent to that of the mechanical mixing type at a lower coagulant dosage. On the other hand, the removal of NOM as disinfection by-products (DBPs) precursor by chemical coagulation (CC) has been extensively studied. It is well reported that enhanced coagulation (EC) by adjusting the pH downwards to 4-5 prior to coagulant addition will encourage the formation of soluble NOM–Al complex from low-turbidity waters. In case of most waters, therefore, acid must be added to maintain the desired coagulation pH for EC, and excess coagulant is required to improve the removal of NOM. However, CC using in-line hydraulic jet mixer such as PDM is a reasonable method for the improvement of coagulation process compared to EC, since it is possible to obtain good removals of NOM as well as turbidity using a lower dosages of coagulant without supplementary addition of chemicals for pH control and thus producing a smaller volume of waste solids.

Development of a Continuous Plug Flow Process for Preparation of a Key Intermediate for Brivanib Alaninate

A thermal runaway potential was identified for the conversion of a tertiary alcohol to a hydroxypyrrolotriazine intermediate in the synthesis of brivanib alaninate. A continuous process was developed to mitigate the potential thermal runaway and allow for safer scale-up. This paper describes the hazard analysis, process development, reactor development, reaction engineering model development, and scale-up of the continuous process. The process includes three separate and stable feed streams that are mixed in distinct order using in-line static mixers. Heat exchangers are arranged and connected to facilitate a “plug flow” reactor scheme allowing sufficient residence time for reaction completion. The process has been scaled-up to the pilot plant and to manufacturing.

A Numerical Study of the Global Performance of Two Static Mixers

The use of in-line static mixers has been widely advocated for an important variety of applications, such as continuous mixing, heat and mass transfer processes, and chemical reactions. This paper extends previous studies by the authors on industrial static mixers and illustrates how static mixing processes of single-phase viscous liquids can be numerically simulated. Mixing of Newtonian, shear-thinning, and shear-thickening fluids through static mixer, as well as thermal enhancement by static mixer is studied. Using different measuring tools, the global performance and costs of SMX (Sulzer mixer X) and helical static mixers are studied. It is shown that the SMX mixer manifests a higher performance; however, the required energy to maintain the flow across a SMX mixer is significantly higher.

Using in-line static mixers to intensify gas–liquid mass transfer processes

A novel static mixer design (screen-type elements) capable of taking advantage of the interfacial characteristics of industrial gas/liquid systems was developed. The interfacial area of contact, and volumetric oxygen transfer coefficient, were investigated using a 25.4 mm pipe loop in which liquid superficial velocities of up to 2.0 m/s (and gas holdups as high as 0.15) were tested. Volumetric mass transfer coefficients as high as 0.44 s - 1 were achieved. The ability of this design to achieve high energy utilization efficiencies is validated by achieving oxygen transfer rate as high as 4.2 kg/kWh in the presence of surfactants. Depending on the process requirements and the interfacial properties of the system, high volumetric oxygen transfer coefficients or high energy utilization efficiencies can be achieved by modifying the contactor design and/or operating conditions.

Emulsion Polymerizations in a Pilot-Scale Loop Reactor with Inline Static Mixers

Emulsion polymerizations of methyl methacrylate were carried out in a pilot-scale tubular reactor configured in a batch-loop mode. The tubular sections of the reactor were fitted with in-line static mixers to incite low-shear mixing. The reactor was used to investigate the influence of different recipes and operating conditions on reaction, particularly on the monomer conversion and the polymer particle-size distribution. Experimental data were compared to equivalent bench-scale studies using a conventional stirred flask. A mathematical model was also developed for predicting the temperature dynamics and the conversion of methyl methacrylate polymerization in the pilot-scale reactor. Conversions and particle-size distributions of the pilot-scale loop reactor were found to be very similar to that of the bench-scale studies. The results indicate that in-line static mixers can help to maintain emulsion stability and provide a means for good temperature control, without unduly influencing polymer particle-size distribution. © 2005 American Chemical Society.

Calorimetric estimation for a batch-loop emulsion polymerisation reactor

To facilitate the online monitoring and control of a pilot-scale polymerisation reactor, state estimation techniques are investigated. Specifically, a batch-loop reactor is employed for the emulsion polymerisation of methyl methacrylate. The reactor consists of jacketed tubular sections fitted with in-line static mixers, thus providing mixing homogeneity and improved temperature control. A direct estimation of the reaction rate is attained through measurements of process and jacket side temperatures, and thus a calorimetric method of estimation. This is compared with a Kalman filter based calorimetric approach, in which there is compensation for model uncertainties and measurement noise. For both estimation methods, no knowledge of the kinetic model for polymerisation is needed. Experimental results indicate that with an accurate model of the process energy balance, in which, for example, the recycle pump energy input is described, the Kalman filter approach is found to provide excellent prediction of conversion, for both high and low conversions, for this pilot-plant reactor system. The approach does not require any (approximate) kinetic knowledge, and is thus considerably easier in implementation than the extended Kalman filter approaches.

Polymerisation of methyl methacrylate in a pilot-scale tubular reactor: modelling and experimental studies

A pilot-scale tubular reactor fitted with in-line static mixers is experimentally and theoretically evaluated for the polymerisation of methyl methacrylate (MMA). A non-isothermal and non-adiabatic axially dispersed plug-flow model is used to describe the flow characteristics of the reactor. The model is applied to the polymerisation of a concentrated MMA solution (up to 72% (v/v)). Key model parameters were attained through independent bench and pilot-scale experiments. Measured monomer conversions and polymer molecular weight were accurately predicted by model simulation. The presence of static mixers is shown to give near-ideal plug-flow operation for the experimental conditions of this study. Furthermore, an approximately four-fold increase in overall heat transfer coefficient is indicated due to the radial mixing incited by the mixers. Studies also demonstrated the importance of inhibitor kinetics on the dynamic and steady-state performance of the reactor.

Flocculation in flow through pipes and in-line mixers

A laboratory investigation was performed on flocculation following the addition of polymer to slurries flowing through pipes and in-line (static) mixers. Results are presented showing the effects of flow velocity, pipe length, inline mixer elements and the use of multiple addition points. Flocculation performance was measured by the settling rate and the supernatant turbidity. The effects of agitation and mixing time are shown to be generally consistent with the results of equivalent tests (both batch and continuous) conducted in stirred tanks.

Hydrodynamics and heat transfer of rheologically complex fluids in a Sulzer SMX static mixer

In-line static mixers are widely used in continuous mixing, heat and mass transfer processes and chemical reactions. However, a good grasp of the hydrodynamics and heat transfer is still missing when rheologically complex fluids are involved. This paper presents a study of the hydrodynamics through Residence Time Distribution (RTD) determination and pressure drop, heat transfer and mixing mechanism in a Sulzer SMX static with both Newtonian and rheologically complex fluids. A RTD model and a correlation of friction fanning factor f/2 are proposed to explain the flow pattern inside the mixer. A general heat transfer coefficient correlation shows an enhancement of a factor about 5 with respect to an empty tube. The state-of-the-art chaos analysis applied to the temporary measurements of resistivity or temperature demonstrates that the mixing mechanism is chaotic in the Sulzer mixer.

A simple stochastic model of two phase flow pressure drop accompanied by boiling inside circular tubes with in-line static mixers

A simple stochastic model has been developed for boiling pressure drop inside a circular tube with in-line static mixers. This model gives rise to the dimensionless correlating equation of the form: [f] = a[Pr m] −1 2 [Re L] −1 μm μ L ρ ρ −1 2 H se + xH LG C pmΔT −1 2 This correlation shows good agreement with the experimental data.

Pressure drop of two-phase flow through circular tubes with in-line static mixers accompanied by condensation—Simple stochastic modelling of the data

Pressure drop of two-phase flow through circular tubes with in-line static mixers accompanied by condensation—Simple stochastic modelling of the data

Surface renewal model of condensation heat transfer in tubes with in-line static mixers

A surface renewal model has been developed for condensation heat transfer inside a circular tube with in-line static mixers. This model gives rise to the following dimensionless correlating equation: [ Nu] = C[ pr][ Re l ][ μ l μ m ][ d L ][ p m p ̄ l ] 1 2 [(1−x)H fg + H sp+ C pmΔT] 1 2 The constant C was determined experimentally.