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View Diary: Morning Feature: Mass Transit - Our Lives and Footprints (Plus Kossascopes) (185 comments)

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  •  Energy input (1+ / 0-)
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    ultrasound generators can be fairly inefficient, and soupy messes such as algae cultures can further waste some of the generated ultrasound. Then the sound make not be real effective at disrupting the cells walls, taking much more energy than expected.  Ultrasound cell disruption is used all the time in the laboratory, but efficiency is not an issue there.

    OriginOil has some good ideas, but there's very little published in the scientific press so evaluation is difficult.  What they've done is not unusual, you have an interesting process that may become practical, so you patent it and hope that you can refine it. Perhaps you are getting some more venture capital to help out, boosted by the optimist tone of the patent and PR you turn out, and you genuinely think the process can be made economically successful with that additional funding.

    Harvesting seems to be the biggest stumbling block for algae derived fuels; a bit similar to processing ethanol from fermentation - a dilute starting point and somewhat energy intensive to concentrate.

    •  Thank you. It would seem that if the cells were (0+ / 0-)

      fully hydrated the tension on the walls would make them more susceptable to disruption by the US. Do they use weak osmotic solutions to adjust the fluid balance in the cells prior to US?

      Information is abundant, wisdom is scarce. The Druid

      by FarWestGirl on Sat Jul 04, 2009 at 11:10:12 PM PDT

      [ Parent ]

      •  in the lab - sometimes (0+ / 0-)

        and sometimes just use osmotic pressure to burst the cells, if the particular cells have weak walls.  A lot of methods, depending on what is being processed and the goals.

        There's been a lot of work on concentrating algae cultures for harvesting purposes. Ingenious mechanisms that don't use much energy, but are prone to clogging. Clog-prove ones that take a lot of power. Cleaver ones that take too much maintenance.  It simply isn't an easy task.

        I suspect that a workable solution is a genetically engineered variety that needs special, although not too hard to provide, conditions to grow as a way to keep it from spreading in the wild, and that takes on a clumping behavior when triggered by some low cost means. The clumped masses would be easy to strain out, possibly floating to the surface through entrained gas bubbles (plus the oils they make).  As starvation, particularly nitrogen starvation, usually triggers oil formation, a similarly triggered but delayed formation of sticky polysaccharides that bound the cells into a mat and trapped the O2 they give off might work. The combined buoyancy of oil and gas floats the mats, concentrating the cells enough that the more energy intensive harvesting methods could be used.


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