1. Field of the Invention
This invention relates to an apparatus for cultivating photosynthetic organisms. The apparatus can be used in a renewable energy system, such as a system which uses biomass to produce fuels, e.g., ethanol and bio-diesel; chemicals, e.g., glycerin; and dry distilled grains (DDGs) for feeding livestock, e.g., cows. A multitude of these apparatuses for cultivating photosynthetic organisms may be interconnected in parallel, series, or a combination thereof in order to increase algae production. The invention also relates to a process for cultivating photosynthetic organisms in a renewable energy system.
2. Description of Related Art
Renewable energy processes may involve one or more renewable energy resources, such as solar, wind, water, plants, animals, and municipal wastes, since these resources always exist. Renewable energy resources generally offer clean alternatives to fossil fuels, e.g., coal, oil and natural gas, for supplying most energy needs, since the renewable energy resources produce very little or no pollution or greenhouse gases.
A prior art renewable energy process uses coal bed methane, coal gasification, and landfill gas recovery for biogas production used to produce steam, heat, and electricity needed in the cycle. Manure slurries are used to produce dry fertilizer products for fertilizing the corn fields. The corn is used in the production of ethanol and bio-diesel. Such a process is illustrated in the brochure entitled “Where Can Fluid Engineering Help Your Bio-fuel Plant?” provided by Fluid Engineering, Erie, Pa.
Among many things, this illustration shows that carbon dioxide produced within the system can be bubbled into ponds to grow algae that can be converted into bio-diesel fuel, and one source of carbon dioxide is from the fermentation tanks for the corn. Corn is used to produce DDGs for feeding livestock. Corn, corn oil, algae, and other products are used to produce bio-diesel which is made through a chemical process called transesterification, whereby glycerin is separated from the fat and/or vegetable oils. The transesterification process leaves behind two products—methyl esters, which is the chemical name for bio-diesel, and glycerin, which is used in food and beverages, pharmaceuticals, cosmetics and toiletries, paper and printing, textiles, livestock, and biodegradable packaging.
It can be appreciated that this prior art renewable energy process involves a complicated system and uses coal bed methane, coal gasification, landfill gas recovery and manure slurries as its main input components for producing outputs such as ethanol and bio-diesel.
Algae culture is often done in ponds and lakes which are open to the elements. This type of culturing is vulnerable to contamination by microorganisms, such as bacteria. Open pond systems do not allow control over water temperature and lighting conditions. In addition, the growing season is largely dependent on location and is limited to the warmer months. These factors limit the number of species successfully cultivated in an open-pond system. However, open-pond systems are often less expensive to operate and offer large growth areas.
Algae may also be grown in closed systems, often referred to as a photobioreactor. A photobioreactor incorporates some type of light source. These structures are generally smaller systems, and, for economic reasons, often do not solve many of the problems associated with an open system.
One advantage to utilizing algae in a renewable energy system is that this organism can grow in salt water, freshwater, or even contaminated water. In addition, algae show accelerated growth in the presence of excess carbon dioxide (the main greenhouse gas) and organic material like sewage. Algae may be used to clean carbon dioxide or untreated sewage. The oil produced by algae can then be harvested and converted into bio-diesel and the algae's carbohydrate content can be further fermented into ethanol. Both of these substances are much cleaner burning fuels than petroleum-based diesel or gas.
One impediment to the expansion of large scale algae culture for pollution abatement has been the difficulty in developing an efficient and cost effective culture system. Growth in large open environments makes control of the temperature, nutrient, carbon dioxide and light levels difficult. Thus, a need exists for the controlled optimization of growth conditions in a closed culture environment.
According to one aspect, the invention is directed to an apparatus for cultivating photosynthetic organisms, comprising: a chamber for growing photosynthetic organisms in a liquid medium; a device for holding the photosynthetic organism; a carbon dioxide source; a medium intake source; and a system for providing movement of the liquid medium within the chamber. According to one embodiment, the apparatus is constructed of a material that is at least partially transparent to light or configured to transmit or reflect light, such as plastic, glass, fiberglass, alloy steel and aluminum. The surface of the apparatus can be lined with a light reflective material, such as aluminum or alloy steel. The chamber can be enclosed or partially enclosed and can be radiused. The light source can comprise an artificial light source or can be a combination of an artificial light source and sunlight. The artificial light source can comprise Fresmel-lense-based lenses, a Himanari solar concentration and transmission system, and a mirror based optical wave guide solar lighting system. The liquid medium movement system can comprise a paddle wheel. The carbon dioxide can be provided from a power generation system or an engine system and the medium intake source can comprise a water source and a nutrient source. The nutrient source can be provided from agricultural waste or municipal sewage. The apparatus can include one or more monitors to measure temperature, pH, carbon dioxide, light intensity, and oxygen levels in the liquid medium. The device for holding the photosynthetic organism can comprise a perforated plate barricade located within the chamber which is in contact with the moving liquid medium for holding the photosynthetic organism in a fixed position. The apparatus can further include at least one of a gas sparger for introducing gas or air bubbles into the liquid medium and an agitation member to enhance movement of the liquid medium. The apparatus can also include a liquid medium outtake for removal of liquid medium used for the culture of the photosynthetic organism. A heat source can be provided for maintaining a predetermined temperature within the system based upon the photosynthetic organism culture being grown.
According to another aspect, the invention is directed to a system for cultivating photosynthetic organisms comprising a plurality of apparatuses. Each of the apparatuses comprises a chamber for growing photosynthetic organisms in a liquid medium; a device for holding the photosynthetic organism; a carbon dioxide source; a medium intake source; and a system for providing movement of the liquid medium within the chamber. The plurality of apparatuses can be interconnected in parallel, in series, or in a combination thereof. The plurality of apparatuses can be stacked in a multi-level design which allows for the simultaneous growth culture of different photosynthetic organisms. The apparatuses can have separate light sources, medium supplies and carbon dioxide supplies. According to another design, the apparatuses can share common medium and carbon dioxide supplies. The apparatuses can be movable with respect to one another and/or to change the angular orientation thereof.
According to yet another aspect, the invention is directed to a method of cultivating a photosynthetic organism, comprising the steps of providing the photosynthetic organism to an apparatus; feeding a medium into the apparatus; moving the medium through the apparatus; adding nutrients and carbon dioxide to the medium; and providing a light source to the apparatus. The apparatus for receiving the photosynthetic organism can be formed from a material that is at least partially transparent to light or configured to transmit or reflect light. The light source can comprise an artificial light source, sunlight, or a combination of both. The method can further include the step of agitating the liquid medium.
These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description with reference to the accompanying drawings, all of which form a part of this specification.
A renewable energy system 10 of
As shown by arrow 32 in
As shown by an arrow 48, electric power is delivered to the bio-diesel unit 16 to produce bio-diesel fuel, as indicated by an arrow 50, which can be used directly in any type of diesel engine or can be shipped to domestic and international markets for human use. As shown, the bio-diesel fuel is produced from algae oil, as indicated by an arrow 52, animal fat or yellow fat, as indicated by an arrow 54, corn oil, as indicated by an arrow 56, and soybean oil, as indicated by an arrow 58. As discussed hereinabove, bio-diesel fuel is made through a chemical process referred to as transesterification, whereby glycerin is separated from the fat and vegetable oils. The glycerin may be used in the manufacture of glycerol soap as shown by an arrow 60, used to treat lumber, as shown by an arrow 62, and is used as bio-diesel fuel, as shown by an arrow 64. One of skill in the art would recognize that the glycerin produced by this process may have multiple applications. Bio-diesel fuel has advantages over diesel fuel which is made from fossil fuels, e.g., coal and natural gas, in that it burns cleaner, is renewable, and does not cause air pollution. Also, bio-diesel fuel can be made from cooking oil and other types of fresh oils.
To the left of the bio-diesel unit 16 of
To the left of algae farm 18 of
To the left of corn unit 20, and as indicated respectively by arrows 102 and 104, electric power and steam from power plant 14 is delivered to corn stover unit 22, which are used to produce ethanol and biomass, as indicated by arrows 106 and 108, respectively. This corn stover unit 22 produces approximately 20 million gallons of ethanol per year. In one non-limiting embodiment, as indicated by an arrow 106, the ethanol is also delivered to railroad car 94, which is then shipped for human use. As is known, corn stover is a by-product of corn and is made from stalks or husks that remain once the corn is harvested. As indicated by an arrow 108, the cornhusks and stalks, now considered as sources of biomass energy, are delivered, as indicated by an arrow 110, to the biomass unit 12. The amount of ethanol produced is a function of the size of the corn stover unit 22 and amount of corn stover supplied thereto.
The fermentation cycle unit 24 is located between and is associated with corn unit 20 and the corn stover unit 22 in
An additional aspect of the renewable energy system of the invention involves the use of algae as a bio-fuel. The invention contemplates the practice of algaculture (farming algae) for making vegetable oil, bio-diesel, and other biofuels. However, it should be understood that the present invention is not limited to the production of algae, but may be applicable to the culture of other photosynthetic organisms. The term “photosynthetic organism”, as used herein, includes any organism capable of photosynthetic growth. These terms may be used to include organisms modified artificially or by gene manipulation.
The inventive system of the invention utilizes algae to treat agricultural waste or sewage to remove toxins. The system can be used to remove pollutants emitted into the atmosphere from a facility and to produce biomass that can then be converted into non-fossil fuels. This system can be used for treating wastes produced by treatment plants, agricultural centers, or other such facilities. The algae or other photosynthetic organisms can utilize the carbon dioxide from these facilities for growth while producing biomass.
In one aspect, illustrated in
In an alternative aspect, the growing chamber may be partially enclosed, thus allowing the access of environmental air, nutrients, and/or light.
In an additional aspect of the invention, one nutrient source for the algae farm is waste water from the treatment of sewage, agricultural power generation, or flood plain run-off, all currently major pollutants and health risks. It is useful to first treat this waste water by processing with bacteria, through anaerobic digestion. Processing of the waste water prevents contamination of the algae. The organic waste is converted to a mixture of carbon dioxide, methane, and organic fertilizer. Organic fertilizer, which exits the digester as a liquid, may first be cleaned and sterilized. Growth of the algae can be increased and accelerated when fed extra carbon dioxide (the main greenhouse gas) and organic material like sewage.
In an additional aspect, as illustrated in
The greenhouse 130 and algae farm 18 will now be described in more detail. In order to grow and maintain a pure algae culture, control outdoor parameters and extend growing parameters, the present invention allows for indoor culturing using bioreactors and waste carbon dioxide. The present invention further allows for lipid production for bio-diesel and other compositions, based upon the optimization of outdoor culture parameters, including carbon dioxide utilization.
As illustrated in
The term “liquid medium” as used herein, refers to any liquid containing sufficient nutrients to facilitate the growth of the photosynthetic organism. Generally, the liquid medium comprises water with added nutrients. Suitable mediums sufficient to support the growth of photosynthetic organisms are well known in the art.
As indicated in
Referring again to
Algae bed 270 includes a system for providing movement of the liquid medium. In one embodiment, this liquid medium movement system comprises a paddle wheel system 277 which allows for the continuous movement of the liquid medium in the device. Paddle wheel 277 provides variable speed movement of the fluid in which the algae is grown. Paddle wheel 277 also allows for a mixing feature to increase gas-liquid mixing within the bed. The photosynthetic organism is held in a fixed position through the use of a perforated plate barricade 280. Nutrients and fertilizer are fed into the water on the back side of the perforated plate barricade and paddle wheel 277 as indicated by arrow 278. Paddle wheel 277 acts to mix the nutrients with the water as it is circulated throughout algae bed 270.
The present system utilizes supplementation with carbon dioxide to increase algae growth. Typically, algae grown in a pond require seven to nine days to grow from bud to maturity (ready to harvest). The use of carbon dioxide enhances algae growth. The present system, which provides supplemental carbon dioxide, shortens the growth phase to three to four days, thus allowing for an increased number of harvests per year. Algae bed 270 includes the addition of a continuous fresh supply of carbon dioxide (as represented by arrow 282). The carbon dioxide is injected into the apparatus provided by a gas sparger tube 284 and placed in front of the perforated plate barricade 280. A “gas sparger tube” refers to any device configured to introduce gas or air bubbles into the liquid nutrient medium. Suitable gas sparger tubes are well known to those of skill in the art. The carbon dioxide is provided to the algae bed 270 from power generation system 166 or the methane gas engine 220. Movement of the nutrient water by paddle wheel 277 over the carbon dioxide sparger tube 284 provides an enriched nutrient feed for the algae. The carbon dioxide and nutrient feeds may further comprise agitation and tubular gas flow systems, containing bubble columns, air lines, and flat panel air lifts with baffles (now shown) to ensure proper movement of the water. Algae bed 270 also contains a liquid medium outtake 226. This allows for the removal and replacement of the liquid medium used for the culture of the photosynthetic organism.
It is important to control the liquid medium temperature in order to maximize photosynthetic organism culture. The specific temperature requirements will depend on the species of organism in culture. For the culture of algae, the nutrient water should be maintained at a temperature from about 10° C. to about 40° C. In the present invention, the heat utilized to maintain the water temperature is provided in the form of low pressure steam heat from the steam turbine 180 and power generation system 166, such as shown in
Algae bed 270 may optionally contain various probes and monitors for the measurement of temperature, pH, carbon dioxide, oxygen, light intensity, and other environmental factors. The apparatus may also contain instruments to measure liquid and gas flow rates, as well as illumination intensity levels in the medium.
Algae bed 270 may be arranged in a geometry other than the straight angles illustrated in
The algae bed apparatus of the present invention can comprise a plurality of identical or similar beds interconnected in parallel, series, or in combination. A parallel configuration of multiple algae beds increases the capacity of the greenhouse 130. In one embodiment, illustrated in
The algae beds of the invention may be positioned by platforms 286 and support posts 288 as illustrated in
Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of this description. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
This application claims priority from U.S. Provisional Application No. 61/180,267, filed May 21, 2009, which is incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
61180267 | May 2009 | US |