Algae Biofuel Farm: Photobioreactor Harvester Extraction System

Sharing is caring!

Sustainable fuel sources are incredibly important and will become more so as the world continues to deplete fossil fuels. Biofuels hold great promise as renewable fuel sources. The key is making production processes of these fuels as efficient as possible. The concept below is my idea for an algae photobioreactor and harvester system. This system would remove the need for expensive and energy-draining dryers, conveyors, and centrifuges in the production of algae biofuel.

Algae Photobioreactor Harvester Extraction System

The problem with current algae biofuel systems:

Most systems currently available are not energy efficient, use massive amounts of electrical energy, and materials and equipment are highly expensive.

Economically inefficient and energy-intensive algae farming systems require massive energy and expensive equipment and technology to operate. This drives up the cost per gallon of biofuels and byproducts produced with the leftover algal biomass after oil extraction.

The solution: 

The concept is simply to use gravity-fed systems to drain the photobioreactor tanks containing the algae/water into a larger steel cylinder similar to a giant tank, then use a hydraulic ram to press all liquid water and oil from the algae through a steel/charcoal filtration system. This should, if it works, remove all need of dryers, lighting, conveyors, and centrifuges which require massive amounts of electrical energy to operate.

After pressing the algae through the system, there would be a large “plug” of biomass left over which can be dried and palletized outdoors, using the sun’s energy. This material can then be processed into feedstock, other products, or sold as biomass to pharmaceutical companies.

The hydraulic ram system pushes the water and oil through the filtration system into an oil/water separator tank, whereby the water can be drained via gravity back into the large culture tank.

The oil can then be drained into a holding tank to be processed into biofuel.

Gravity Fed System

This whole concept uses gravity flow in both directions. It also minimizes the use of electric water pumps. In this system, there is only 1 pump and 1 hydraulic ram which uses electricity. The hydraulic ram can be powered by biodiesel fuel (which we just happen to produce) or electricity power by solar energy.

The culture tank is a “water tower” 100 feet in the air, providing more than enough pressure to fill all the photobioreactor tanks. The water tower can be filled using a small 10,000/gallon/hour pump.

Since the photobioreactor/grow tanks are vertical, draining them into the steel cylinder/press is simple and uses no energy other than gravity. The hydraulic ram is the only energy consumer in this line. Then the oil/water is separated via gravity with a simple valve system at the base of the oil/water separator tank, which feeds into the culture tank, completing the closed-loop system.

Oil is lighter than water and floats on top of the water. Once the water is drained out of the separator tank, the second valve can be flipped and the oil drains into the oil tank. At that point that oil merely needs to be filtered/cleaned, which can also be powered by a gravity-fed oil filtration system.

Governments and corporations are turning to microalgae for biofuel and feedstock solutions.

Some species of algae produce 50% or more lipids (oils) through a photosynthetic process. These oils can be extracted from large algae farms to produce biofuels like biodiesel, biogasoline, and biojetfuel, as well as plastics, adhesives, and cosmetics. They can even be used for products such as protein pills, pharmaceuticals, and feed for livestock. Algae-based biofuels are being considered as a substitute for fossil fuels.

Method: Form a small scale pilot project farm to test the feasibility of the system.
Budget: $100,000 5 Person TEAM: Director, Manager, Designer, Engineer, Scientist

OIL PRODUCTION VOLUME (Yield) per 5000 gallons algae/water: One 5000 gallon vertical photobioreactor tank will produce approximately 4.71 gallons of algae oil per day.

Yield per 5000 gallon tank:

• Daily = 4.71 gallons
• Monthly = 141.3 gallons
• Quarterly = 423.9 gallons
• Annual = 1719.15 gallons

82,519.2 GALLONS OIL PER ACRE

48 tanks per acre of land = 82,519.2 gallons oil annual yield 100 acres = 4800 tanks = 8,251,920 gallons oil annual yield

DOUBLE YIELD: Conceptually, we can double the yield by going vertical/higher with the same diameter tanks. Going to a 10,000 gallon 4800 tank system will produce approximately 16,503,840 gallons of oil annually.

There are approximately 1.7 grams algae per liter of water, so 3.78 liters water per gallon = 6.42 grams algae per gallon. 50% algae by weight is oil 5,000 Gallon Tank x 6.42 grams algae per gallon = 32,100 grams algae 50%

Oil content: 32,100 / .5 = 16,050 grams oil per tank 3401.25 grams algae oil per gallon

16,050 grams oil per tank / 3,401.25 grams oil per gallon = 4.71 gallons algae oil per 5000 gallon tank

[Based on liquid volume measurements: ~7.5 Pounds per gallon 453.5 grams per pound)]

————————————————————–

This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 Generic License.