Experimental and numerical investigations of mixing in raceway ponds for algae cultivation

Prussi, Matteo; Buffi, Marco; Casini, David; Chiaramonti, David; Martelli, Francesco; Carnevale, Mauro; Tredici, Mario R.; Rodolfi, Liliana

doi:10.1016/j.biombioe.2014.05.024

Cited by 69 publications

(38 citation statements)

References 19 publications

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“…The intensity was calculated to be 3.5-4% for the range of inlet velocities tested; this was similar to the value found in other CFD investigations into raceways [36]. As the use of this formula is an approximation and the intensity at the inlet is unknown and dependent upon the upstream history of the flow an intensity of 5% was chosen as the recommended value [43].…”

Section: Boundary Conditionsmentioning

confidence: 54%

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Investigating the hydrodynamic performance of carbonation sumps in High Rate Algal Pond (HRAP)raceways using computational fluid dynamics (CFD)

Musgrove

Heaven

2014

Biofuels

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The production of microalgae requires carbonation and deoxygenation which is commonly supplied through a sump. This needs to be designed to minimise the energy loss to ensure a high net energy gain from the biofuel. Computational fluid dynamics was used to evaluate different sump designs and flow velocities in terms of energy loss and flow distribution to find the optimum configuration. It was established that increasing the radius of curvature of the corners to 0.1 m and the implantation of one flow deflector resulted in a reduction in hydraulic power of 73% compared to the basic setup. It was apparent that the central baffle resulted in considerable energy loss and when this was removed than a power saving of 95% was possible. There was, however, a much reduced flow around the sump leading to shortened contact time between the gas and fluid which could in turn decrease the carbonation of the fluid. It was also apparent that the use of standard formulas for the calculation of head loss was not applicable.

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Section: Boundary Conditionsmentioning

confidence: 54%

“…More recently the modelling of raceways has become more sophisticated with the use of free surface models [36,37]. Some studies have even modelled the motion of the paddlewheel within the mesh [38].…”

Section: Introductionmentioning

confidence: 99%

Investigating the hydrodynamic performance of carbonation sumps in High Rate Algal Pond (HRAP)raceways using computational fluid dynamics (CFD)

Musgrove

Heaven

2014

Biofuels

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“…This is evidenced by the growing volume of experimental and numerical studies exploring the three-dimensional idiosyncrasies of these facilities (see e.g. Hadiyanto et al, 2013;Mendoza et al, 2013;Hreiz et al, 2014;Prussi et al, 2014). In particular, this study will focus on secondary currents in the plane perpendicular to the streamwise flow.…”

Section: Physical Processes: Open Channel Turbulencementioning

confidence: 99%

“…This is evidenced by the growing number of physical and numerical studies into the hydrodynamics of these facilities (see e.g., Hadiyanto et al, 2013;Mendoza et al, 2013;Li↵man et al, 2013;Prussi et al, 2014;Hreiz et al, 2014;Ali et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Identifying the dominant physical processes for mixing in full-scale raceway tanks

2018

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Biodiesels from microalgae are a promising alternative to fossil fuels with a number of unique benefits over other alternative fuel sources. However, to date, their viability in the fuels market remains infeasible due in part to a number of ine ciencies in the cultivation process. This has led to a growing interest in the hydrodynamics of open raceway tank (RWT) reactors, and cultivating conditions that are favorable to algae growth. In particular, two impediments require attention: the lack of vertical mixing in the straight portions of the reactor, and the need for e cient introduction of atmospheric carbon into the growth medium. It is proposed that the promotion of cellular, secondary currents by introduction of longitudinal ridges along the bed of the reactor can both promote vertical mixing and enhance gas transfer across the free surface of the growth medium. Experiments are performed in a full-scale open RWT at the University of Illinois, Urbana-Champaign, Ecohydraulics and Ecomorphodynamics Laboratory (EEL), in which the bed of the RWT is modified with longitudinal ridges of two di↵erent sizes, triangular and semi-circular cross-sections, and variable spacing.The 3-dimensional velocity components are monitored at significant locations in the reactor by means of acoustic doppler velocimetry (ADV) and surface particle image velocimetry (sPIV), and the gas transfer across the free-surface is measured by re-aeration curves of dissolved oxygen (DO). It is found that the cellular, secondary cells can be visualized in the velocity data after the introduction of longitudinal ridges. However, the impacts at the free surface are limited and consequently so is the gas transfer. A range of flow structures are observed that impact the relative significance of these cellular currents, including: vortex shedding from bend vanes, secondary currents of Prandtl's first kind induced by the ii bends, paddlewheel pulsation, and boundary layer development. These structures are found to overwhelm the presence of the cellular currents, and indicate that flows in the straight portions of the RWT reactor are a complex composite of boundary layer flow, secondary currents, resonance structures, energy input conditions, and shear flows. If cellular, secondary currents are to be used to promote the ideal algae growth conditions, further developments on this method will be required to overwhelm or work cooperatively with the dominant bend-induced dynamics.iii To Jarah.

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“…Mixing also accounts for nearly 69% of total utility costs (Hreiz et al, 2014). The importance of sufficient mixing includes (1) periodic exposure of cells to sunlight, (2) keeping cells in suspension, (3) availability of the nutrient to algal cells, and (4) removal of photosynthetically generated dissolved oxygen to avoid photooxidation and photoinhibition by respiration, thereby enhancing light utilization efficiency (Chiaramonti et al, 2013;Prussi et al, 2014;Kumar et al, 2015). As a result, the mixing level should be adjusted according to the environmental conditions; for example, the mixing velocity should be reduced during the night and even in winter time to avoid excess biomass loss in the absence of light.…”

Section: Mixingmentioning

confidence: 99%

Challenges and Perspectives on Carbon Fixation and Utilization Technologies: An Overview

Ping

Pan

Pei

et al. 2016

Aerosol Air Qual. Res.

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This paper provides an overview of state-of-the-art carbon fixation and utilization technologies. Several carbon capture processes, such as chemical absorption and chemical looping, are reviewed and illustrated. In addition, various types of chemicals and fuels that can be produced using concentrated CO 2 (or other forms) through physical, chemical, or enhanced biological methods are presented. Among those carbon conversion methods, two promising approaches, i.e., microalgae ponds and accelerated carbonation using alkaline solid wastes, are reviewed in detail. Microalgae are fast-growing and ubiquitous photosynthetic organisms, which are rich in protein and can be converted to biodiesel fuel. They have been recognized as an alternative feedstock not only because they use CO 2 from the atmosphere but also due to their high lipid content per biomass compared to other plants. In this study, for the microalgae technologies, the principles and applications of open pond systems are discussed in terms of both technological and economic considerations. The important operation parameters affecting productivity of microalgae, including light intensity, temperature, mixing, CO 2 delivery, accumulation of dissolved oxygen, and salinity are summarized. On the other hand, accelerated carbonation technologies are an attractive and feasible approach to integrating alkaline solid waste treatment with CO 2 fixation and utilization. In this study, the performance of various carbonation processes is critically reviewed from the perspectives of process design, energy consumption, and environmental benefits. The carbonated solid product can also be used as supplementary cementitious materials in a blended cement or concrete block. Accordingly, the performance of cement pastes with carbonated product, in terms of workability and strength development, are evaluated from the cement chemistry point of view. Cement manufacturing is an energy and material intensive process, with high annual production. It is noted that, through the accelerated carbonation process, significant indirect environmental benefits can be realized.

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Experimental and numerical investigations of mixing in raceway ponds for algae cultivation

Cited by 69 publications

References 19 publications

Investigating the hydrodynamic performance of carbonation sumps in High Rate Algal Pond (HRAP)raceways using computational fluid dynamics (CFD)

Investigating the hydrodynamic performance of carbonation sumps in High Rate Algal Pond (HRAP)raceways using computational fluid dynamics (CFD)

Identifying the dominant physical processes for mixing in full-scale raceway tanks

Challenges and Perspectives on Carbon Fixation and Utilization Technologies: An Overview

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