cavitation
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CT: Photosynthetic algae use sunlight to convert CO2 into natural oils that are suitable for conversion into biodiesel. However, harvesting the algae and extracting the oil are currently difficult and expensive operations. Cheaper and more energy efficient processes are required before mass production of algae can be used to produce biodiesel economically.
The DynaJets® cavitating jets allow collection of lipids and other intracellular material from algae growth media without pre-concentrating the algae. Solutions of algae can be lysed and the released cellular contents including lipids can be recovered.
The cavitation, high shear, and rapid pressure changes cause the algal membranes to rupture and lyse. The triglycerides and other cellular material are then removed from the liquid and concentrated by entraining small air bubbles into the mixture. The hydrophobic compounds partition to the bubble water interface. A stable foam is formed when the bubbles rise to the free surface. The foam is then collected and the lipids recovered.
Extracting and collecting the lipids from the dilute algae solutions avoids costly harvesting and drying processes and reduces the energy required to produce biofuel from algae.
The DynaJets® cavitating jets technology is being further developed for renewable and green energy applications. Dynaflow, is interested in discussing possible applications and collaboration to commercialize this process.

S: DYNA – https://goo.gl/dXW8fm (last access: 17 November 2017)

N: 1. From the English word “cavity”, concept adopted from the French term cavité, from late Latin cavitās, from the ancient Latin cavus: “hollow”.
2. Cavitation is the sudden formation and collapse of low-pressure bubbles in liquids by means of mechanical forces, such as those resulting from rotation of a marine propeller.
3. Cavitation may occur when local static pressure in a fluid reaches a level below the vapour pressure of the liquid at the actual temperature. According the Bernoulli Equation this may happen when a fluid accelerates in a control valve or around a pump impeller.
4. Cavitation is used in the mixing of biodiesel in ultrasonic mixing reactors. Ultrasonic mixing reactors replace tank agitators and other dynamic shear mixers. The ultrasonic reactors are generally installed to mix two feed streams. Oil and methanol (with catalyst). For this, a crude pre-mix is pumped into the ultrasonic reactor, where the ultrasonic cavitation mixes and emulsifies both reagents within 5 to 15 seconds. This is an inline mixing process. When the mix exits the flow cell reactor, the glycerine will separate by gravity within less than 60 minutes. Alternatively, you can feed the mix into a centrifuge after several minutes of residence/reaction time. The inline mixing reduces the number and volume of tanks used for conventional batch processing. This improves capital utilization.
5. Cavitation occurs in the collection of renewable energies processes in which liquid, normally water, is involved. The effect of cavitation is usually considered as negative. The reason is that cavitation produces a fast and regional decomposition around the metal surface caused by the exploding steam bubbles, for example in Geothermal Machines.

S: 1. AHD – https://goo.gl/yh9s6t; AHD – https://goo.gl/wH52Uw (last access: 16 November 2017). 2. AHD – https://goo.gl/v4VQrX (last access: 17 November 2017). 3. TET – https://goo.gl/kz3gLM (last access: 17 November 2017). 4. HIELSCHER – https://goo.gl/3T4pbG (last access: 17 November 2017). 5. Geoth. Energy – https://goo.gl/fL1bTw (last access: 17 November 2017).

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CR: biodiesel , geothermal energy, hydraulic turbine, renewable energy, vane, water hammer.