{"id":2481,"date":"2010-09-29T09:57:42","date_gmt":"2010-09-29T09:57:42","guid":{"rendered":"http:\/\/www.oilgae.com\/blog\/2010\/09\/characteristics-of-major-aerators.html"},"modified":"2010-10-02T05:31:37","modified_gmt":"2010-10-02T05:31:37","slug":"characteristics-of-major-aerators","status":"publish","type":"post","link":"http:\/\/www.oilgae.com\/blog\/2010\/09\/characteristics-of-major-aerators.html","title":{"rendered":"Characteristics of major Aerators"},"content":{"rendered":"

Following the previous post (http:\/\/www.oilgae.com\/blog\/2010\/09\/aeration-in-a-photobioreactor.html<\/a>), here is an analysis of the various aerator designs:
\n1. Ring or Orifice sparger
\nThe stirred tank and flat-plate photobioreactors are generally equipped with a ring sparger for aeration.
\nFeatures & Benefits
\n\u2022 Orifice or ring sparger is essentially a perforated pipe made of a perforated metal tube, a porous ceramic material in the form of a ring. Common types include Single Orifice Sparger (SOS) and Multiple Orifice Sparger (MOS)
\n\u2022 When compared to the SOS for a given gas flow rate, the MOS give better gas holdup distribution in the draft tube, enhance the liquid recirculation, and reduce the fraction of the poorly mixed zones
\n\u2022 Ring sparger comprises a plurality of converging nozzles for air entry
\n\u2022 A typical ring sparger encircles the interior of the base of the bioreactor and contains a large number (several hundred) of nozzles from which air emerges.
\n\u2022 Gas bubbles escape from the sparger and pass upwardly until they escape from the surface of the liquid algal culture medium. A downward movement of fluid also results from the gas sparging.
\n\u2022 Thus, the gas sparging causes a gentle circulation and mixing of the liquid algal culture
\nhttp:\/\/www.freepatentsonline.com\/4322384.html<\/a><\/p>\n

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\n2. Mott sparger
\nMott spargers developed by Mott Corporation, a porous metal-product manufacturer are used for aeration in a photobioreactor during the production of algae for fuel.
\nFeatures & Benefits:
\n\u2022 Mott spargers introduce gases into liquids through thousands of tiny pores, creating bubbles far smaller and more numerous than with drilled pipe and other sparging methods.
\n\u2022 The result is greater gas\/liquid contact area, which reduces the time and volume required to dissolve gas into liquid.
\n\u2022 Mott spargers are constructed entirely of metal, to provide long-lasting operation even in the midst of temperatures as high as 1450\u00b0F under oxidizing conditions.
\n\u2022 Simple, cost-effective, easy-to-install.
\n\u2022 From single elements to manifolded systems, Mott spargers are among the simplest, most affordable and most efficient equipment.
\nhttp:\/\/www.mottcorp.com\/<\/a><\/p>\n

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\n3. Membrane sparger
\nHelical tubular photobioreactors employ membrane sparger for carbon dioxide biofixation.
\nFeatures & Benefits:
\n\u2022 A sparger useful for introducing gas into a liquid is composed of one or more gas-permeable members positioned between a gas inlet means and a gas distribution means.
\n\u2022 Membrane diffusers are constructed with EPDM (Ethylene propylene diene Monomer) membranes for maximum aeration efficiency and operational flexibility
\n\u2022 Hollow fiber membranes are uniformly fitted inside the reactor, which function as a gas sparger and produced small bubbles.
\n\u2022 Membrane sparger delivers small bubbles that give an efficient mass transfer of CO2 from gas to liquid.
\n\u2022 The membrane sparger (elastic) operates as a linear area device, that is, the hole area appears to increase linearly with increasing pressure.
\n\u2022 Few photobioreactors are designed using a membrane sparger in a loop configuration resulting in a large gas\/liquid interfacial area.
\nhttp:\/\/bit.ly\/a8FkoP<\/a><\/p>\n

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\n4. Sintered Air Diffuser
\nFlat-plate and bubble-column photobioreactors employ sintered glass air diffusers to supply air\/CO2
\nFeatures & Benefits
\n\u2022 Bioreactors use a range of sintered glass gas diffusers with differently sized pores to disperse humidified air within the liquid biomedium
\n\u2022 Extremely durable and washable (reusable) air diffusing media
\n\u2022 Manufactured with brown Adamantine Spar (corundum\/alumina) under ultra high temperature and pressure
\n\u2022 Applicable in Acidic or Alkaline waters (low or high pH)
\n\u2022 Ozone resistant
\nhttp:\/\/www.alita.com\/diffuser\/sintered.php<\/a><\/p>\n

<\/a>
\n5. Sandstone and Stainless Steel Disk for Air Diffusion
\nFeatures & Benefits
\n\u2022 A unique method of aeration and mixing in which air is introduced deep into the water layer through a sandstone or stainless steel gas diffusion disk releasing numerous air bubbles are formed in the water phase.
\n\u2022 These numerous water coated bubbles rise through the liquid interface into the ester, carrying large amounts of water in the film
\n\u2022 These bubbles and droplets seem to be of such size and nature that the droplets formed do not remain emulsified when they reach the aqueous phase, but quickly coalesce and disappear into the aqueous layer.
\n\u2022 This method greatly magnifies the interface area, and at the proper aeration rate, half or more of the ester phase volume seems to be filled with quite rapidly settling droplets of aqueous phase
\nhttp:\/\/bit.ly\/aGiuX7<\/a><\/p>\n

<\/a>
\n6. Silicone Rubber Diffuser
\nFlow of air into PBR\u2019s like Fluidized Bed BioReactors (FBBR) is facilitated through fine bubble diffusers made up of silicon rubber.
\nFeatures & Benefits
\n\u2022 High temperature resistance.
\n\u2022 Low susceptibility to encrustation.
\n\u2022 Suitable for most of the algal species
\n\u2022 Less susceptible to degradation by hydrocarbons
\n\u2022 Designed for even distribution of air bubbles throughout the culture medium
\nhttp:\/\/www.alita.com\/diffuser\/siliconehose.php<\/a><\/p>\n

<\/a>
\n7. Porous Tube Diffuser
\nThe porous tube spargers are used in combination with helical baffle flow for aeration in photobioreactors
\nFeatures & Benefits
\n\u2022 The Porous Tube sparging system deliver multiple fine air bubbles to the liquid which allow efficient dispersion of oxygen.
\n\u2022 The sparger is generally made from HDPE (High Density PolyEthylene) and its omni-directional porous structure is an excellent feature to be used for aeration purposes.
\n\u2022 High-density polyethylene tubes have excellent resistance to chemicals and abrasion.
\n\u2022 The sparger is available fine, medium and coarse pore sizes thus providing uniform distribution of fine bubbles
\nhttp:\/\/www.alita.com\/diffuser\/polyethylene.php<\/a><\/p>\n

<\/a>
\nInnovative efforts in Developing an Optimal Aerator System
\nAeration is an important parameter in photobioreactor design and operation to avoid cell death and the decline in productivity. The forthcoming details provide various innovative efforts taken by researchers in designing an efficient aeration system.
\nDual sparger
\nDual sparging laboratory-scale photobioreactor is found to be effective for continuous production of microalgae
\n\u2022 The photobioreactor is designed without moving parts and equipped with two different spargers operated in dual sparging mode.
\n\u2022 Sufficient mixing to keep the cells in suspension is obtained by sparging with air through two single orifice spargers which deliver large bubbles and pure CO2 at a controlled pH
\n\u2022 Through a perforated membrane sparger small bubbles are delivered that give an efficient mass transfer of CO2 from gas to liquid.
\n\u2022 Separation of CO2 supply from air for mixing by dual sparging increases the transfer of CO2 from gas phase to liquid phase five fold relative to conventional sparging.
\n\u2022 The dual-sparger system has the potential to minimize the required aeration rates for mass transfer as well as cell damage by bubble rupture and foam problems in large scale bioreactors.
\nhttp:\/\/www.springerlink.com\/content\/v80g09868g423508\/<\/a><\/p>\n

<\/a>
\nAlgasol Renewables Internal Aeration System
\nAlgasol Renewables, located in Spain is a developer of a unique technology for low-cost cultivation of micro algae in a closed environment
\n\u2022 Algasol Renewables has investigated and tested different internal aeration systems for the aeration and stirring of the algae biomass inside the photobioreactor considering factors including economics, efficiency and scalability.
\n\u2022 The company has successfully launched a new photobioreactor with a fully integrated internal aeration system.
\n\u2022 The new internal aeration system has lowered production cost of algae oil with 10% and the results in terms of productivity and biomass density are very promising.
\n\u2022 Algasol Renewables achieved an average microalgal productivity of more than 60 grams per m2 per day with an average biomass density of more than 4 g\/L.
\n\u2022 These results are a significant milestone in the commercialization of its novel and flexible polymer photobioreactor with internal aeration system.
\n(September 2009)
\nhttp:\/\/www.algasolrenewables.com\/en\/alga2_uk<\/a><\/p>\n

<\/a>
\nConclusion
\nThe aeration rate must be carefully balanced to achieve good mixing, liquid circulation and mass transfer while avoiding shear stress to the algal cells grown in a photobioreactor. Aeration must ensure the oxygen generated by photo-synthesis is removed; otherwise, it can inhibit cell growth. Thus, the above details about the design and operation of aerator systems stress the crucial role of aeration in algal cultivation using photobioreactor.<\/p>\n","protected":false},"excerpt":{"rendered":"

Following the previous post (http:\/\/www.oilgae.com\/blog\/2010\/09\/aeration-in-a-photobioreactor.html), here is an analysis of the various aerator designs: 1. Ring or Orifice sparger The stirred tank and flat-plate photobioreactors are generally equipped with a ring sparger for aeration. Features & Benefits \u2022 Orifice or ring sparger is essentially a perforated pipe made of a perforated metal tube, a porous […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[166,167],"class_list":["post-2481","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-aeration","tag-photobioreactors"],"_links":{"self":[{"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/posts\/2481","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/comments?post=2481"}],"version-history":[{"count":3,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/posts\/2481\/revisions"}],"predecessor-version":[{"id":2517,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/posts\/2481\/revisions\/2517"}],"wp:attachment":[{"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/media?parent=2481"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/categories?post=2481"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.oilgae.com\/blog\/wp-json\/wp\/v2\/tags?post=2481"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}