Examination of the B-240 plastic to oil system for cleaning up the oceans

 

b-240-3g  Updated brochure.

This system fascinates me and I wanted to do a back of the envelope calculation with respect to its cost per kilo of cleaning up the plastic and how many of these you would need to have going to keep up with the plastic in the ocean.

Ok, lets summarize what it claims:

Throuput: 2.7 gal (.0643 barrels)  per hr  from 22 lbs (10 kg)  of plastic.

Per day this produces about 1.5 barrels of oil from 240 kg of plastic.

We can look at this in terms of energy:  Assume density of HHV bio-oil 4.55kg/gal and 17.9 MJ/kg then 2. 7 gal/hr equates to 220 MJ/hr .   The price of bio-oil is running around 6 Euro/GJ so the value of the oil produced is about  1.3 Euro/hr (1.69 $US).

Energy use:   Stated as 7 kw per hr.   Not sure how to intrepret this since it is a power per hour rather than energy per hr.     Energy units are usually kwhr.  If we ignore the per hr and assume it consumes  7kw  then the machine would use 7kwh per hr .   Residential electricity costs about 10 cents per kwhr however on a ship it is probably much higher.   But even at 10 cents per hr it would cost about a $1/hr just for electricity.

Plastic density:

Plastic density varies considerably in the ocean.  For example, sampling in the North western Atlantic showed an avg might be .1 kg/per sqkm up to a max of about 1.4 kg per sq km

Suppose for convience, we assume a plastic density in surface waters to be  1 kg per sq km .  So we would need 10 sq km per hr of ocean clean up to keep this machine going .

How can we get that kind of input stream?  Lets consider two conceptual ways both involving what I call Sea Kites the are flown in the ocean.  Boyan Slat Marine Litter Extraction Array (MLEA) is fixed and the Ralph Schneider Floating Horizon is propelled by the waves.

MLEA concept:

Lets suppose that the sampling is done with a fixed boom that filters sea water out like Boyan Slat’s Sea kites.   The average current assumed in a 5 year gyre rotation is about .2 km per hr so this leads to a boom length of  10 sq km per hr/.2 km per hr  = 50km.

So it appears that with the 1 kg/km plastic density about 1 Sea Kite of 50km would be required to keep this machine busy.

Floating Horizon:

The basic sweep width is 7 m x  2 km/hr = 14 000 sq m/hr   = .014 sq km/hr

To sweep 10 sq km/hr one would need about 700 units and some how be able to consolidate the collection for processing.    Ralph had proposed about 4000 units to clean the entire ocean area with 570 units per service ship.   Thus, one of the machines could be assigned to a service ship.

Cost of Machine and Solar arrays:

B-240   $200,000 ??

Marine quality solar arrays  $8/watt*5000 watt = $40,000

Probably need a plastic shredder , rinser, oil collector, conveyors ..  $300,000

More later:

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One Response to Examination of the B-240 plastic to oil system for cleaning up the oceans

  1. Hi Chris,

    nice calculation.

    Have a good day! 🙂

    cheers Ralph

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