FEDKENHEUER, Alvin, W. (3208 Bearspaw Drive, NWCalgary, AB T2L 1T2, 1T2, CA)
CARIN, Christianne (203 Iverness Park, SECalgary, AB T2Z 3K6, 3K6, CA)
FEDKENHEUER, Alvin, W. (3208 Bearspaw Drive, NWCalgary, AB T2L 1T2, 1T2, CA)
1. A method of processing algae comprising: harvesting wild algae; preprocessing the algal harvest to remove undesirable materials from the harvested algae; and drying the algae with the exhaust gases from a gas turbine generator.
2. The method of claim 1 , wherein the harvesting step occurs in the ocean.
3. The method of claim 2, wherein the harvesting step occurs in the Gulf of Mexico.
4. The method of claim 2, wherein the harvesting step occurs in the dead zone in the Gulf of Mexico.
5. The method of claim 1 , wherein the harvesting, preprocessing, and drying steps are accomplished before the algae are transported over land.
6. The method of claim 1, wherein the harvesting, preprocessing, and drying steps are accomplished on an offshore platform.
7. The method of claim 1 , wherein the harvesting, preprocessing, and drying steps are accomplished on a ship.
8. The method of claim 1 , where the preprocessing step includes washing the algae.
9. The method of claim 1, where the preprocessing step includes filtering the algae.
10. The method of claim 1, wherein the algae are dried without significant oxidation.
11. The method of claim 1 , wherein the algae are reduced in a milling process.
12. The method of claim 1, wherein the algae are processed into a food product.
13. The method of claim 12, wherein the algae are processed into animal feed.
14. The method of claim 1, wherein the algae are processed into fuel.
15. The method of claim 14, wherein the algae are processed into ethanol.
16. The method of claim 14, wherein the algae are processed into biodiesel.
17. The method of producing animal feed comprising: harvesting wild algae from the Gulf of Mexico; drying the algae with the exhaust gases from a gas turbine generator; milling the algae to reduce algae; and mixing the algae with a substrate to create animal feed.
18. The method of claim 17, wherein the substrate includes corn products.
19. The method of claim 17, further comprising a washing step that removes minerals from the algae.
20. The method of claim 17, wherein the harvesting and drying steps occur offshore.
This application is being filed on 19 November 2009, as a PCT International Patent application in the name of EarthRenew, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and
Christianne Carin, a citizen of Canada, and Alvin W. Fedkenheuer, a citizen of the U.S., applicants for the designation of the US only, and claims priority to U.S. Provisional patent application Serial No. 61/116,923, filed November 21, 2008.
Technical Field This disclosure relates to a method and apparatus for economically processing harvested algae.
Algae are fast-growing plant-like organisms. The term "algae" as used herein refers to any of numerous groups of chlorophyll-containing, mainly aquatic, eukaryotic organisms. Algae are distinguished from traditional plants by their absence of true roots, stems, and leaves and by their lack of nonreproductive cells in the reproductive structures.
Algae are comprised of, among other components, lipids (e.g., oils), carbohydrates, and proteins. Algae have many potential commercial uses including, for example, making ethanol, biodiesel, paper, and feed/food products. Example methods of converting algae to fuel are disclosed in: US 7,135,308 titled Process for the Production of Ethanol from Algae; US 2007/0202582 titled Process for the Production of Ethanol from Algae; US 4,351,038 titled Oil Products from Algae; US 2007/0048848 titled Method, Apparatus and System for Biodiesel Production from Algae. An example method of converting algae to paper is disclosed in US
5,500,086 titled Method for Producing Pulp from Green Algae. Example methods of converting algae to food/feed products are disclosed in US 5,715,774 titled Animal Feedstock Comprising Harvested Algal Turf and a Method of Preparing and Using the Same and US 7,208,160 titled Process of Treating Sea Algae and Halophytic Plants.
Algae can be cultivated and harvested like a traditional crop, or wild algae can also be harvested. Harvesting wild algae from the oceans avoids the cost of cultivation, but poses additional challenges relating to the harvesting, processing, and transporting of the algae. There is a need for improved methods and machines for harvesting and processing wild algae.
Summary The present disclosure relates to a method and apparatus for processing algae. The method and apparatus is particularly advantageous in harvesting wild algae. A method of harvesting and preprocessing wild algae offshore is provided. According to one embodiment of the present disclosure, the alga is harvested from a dead zone in the ocean and processed offshore on a ship and/or an oil platform. The preprocessing step can include, for example, the steps of separating the target algae from the harvested material, drying the algae, and/or milling the algae. The algae can be further processed on or offshore. In some embodiments, the algae is washed to decrease the mineral content, and subsequently mixed with other edible materials to result in animal feed. In another embodiment, the algae are converted into fertilizer or fuel.
Brief Description of the Figures
FIG. 1 is a schematic diagram of a process for treating algae using the process and equipment in accordance with the present disclosure.
FIG. 2 is a plan view of the process units according to this disclosure in the form of portable units.
FIG. 3 A is a plan view and FIG. 3B is an elevation view of an illustration of a configuration of the system of this disclosure mounted on a platform.
FIG. 4 is a schematic of processes for processing algae.
Algae blooms in the oceans have created what is commonly referred to as the "Dead Zone." Some estimate that, at times, the dead zone in the Gulf of Mexico stretches for 7,000 square miles off the coast of Louisiana. The scientists believe the dead zone in the Gulf is attributable to the high levels of nutrients, in particular nitrogen, that flow out of the Mississippi and into the Gulf. These rich stores of nutrients feed algal populations which explode during the summer. These blooms eventually fall to the ocean floor. When bacteria begin decomposing the dead algae, they deplete the oxygen from the ocean bottom. The hypoxic conditions result in massive marine life kills.
Some of the algae booms are toxic and can kill marine species by paralyzing their respiratory systems. Some toxic algae produce potent neurotoxins which can be transferred through the food web, affecting or killing higher life forms. The blooms present in the Dead Zone are primarily nontoxic.
The present disclosure provides algae processing systems and methods that can make use of these otherwise undesirable algae blooms. The systems and methods are potentially much more efficient than systems and methods involving algae cultivation, as these systems and methods do not require energy inputs in growing the algae. The systems and methods also can potentially control the algae blooms and thereby ameliorate some of the negative effects of the algae blooms on marine life. The present disclosure provides new technology in the form of processes, apparatus, and systems for conversion of wild algae to useful, environmentally acceptable materials and products. As disclosed herein, the present disclosure provides technology which reduces or eliminates the undesirable environmental impacts of algae blooms in the oceans. The high temperature treatment of algae, preferably by direct contact with hot gases, e.g., >l,000°F, can destroy or convert to harmless forms substantially all undesirable components present in the algae harvest, particularly when such heat treatment takes place for a sufficient time and without significant oxidation, incineration, or pyrolysis of the algae. Drying the algae can also make the algae much easier to transport and otherwise process (grinding, chopping, etc.).
An efficient way of providing the hot gases for contact with the algae is the exhaust from a gas turbine, and preferably a gas turbine electric generator. According to the system of this disclosure, the gas turbine is fueled from locally available conventional fuel sources. The electricity produced from the gas turbine generator can be sold back into the local power grid as a revenue source for the operation of this disclosure, but it can be used internally in the operation of the system of this disclosure or in other nearby operations as a supplemental source of power or in a combination of uses for power and heat recovery from the processes employed in this disclosure. The ability to generate electric power can be especially advantageous when the heat treatment occurs at a location distant from the power grid (e.g., out on a platform on the ocean).
One important feature of the process and apparatus of this disclosure is that the gas turbine and the algae dryer vessel receiving the exhaust gas from the gas turbine are connected together such that induction of outside air into the dryer vessel is precluded, and the dryer vessel preferably receives the exhaust gases directly from the gas turbine. It is preferred that 100% of the gas turbine exhaust gases are passed into the dryer vessel and, for most efficient operation, preferably without passing through any intervening heat exchanger, silencer, or other equipment in order that the dryer vessel receives the maximum heating from the gas turbine exhaust. But, it is recognized that excess exhaust gases not needed for the dryer vessel operation can be diverted to provide heat required in other steps in the systems of this disclosure or in other nearby operations. It is also preferred that the exhaust gases result from conventional and efficient combustion ratios in the gas turbine so that the exhaust gases contain minimum or limited amounts of free oxygen, essentially no unburned fuel, no exposed flame, and that the optimum exhaust gas temperature (EGT) is achieved, for maximum heat produced, per unit of fuel consumed. The combustion can also be at stoichiometric ratio for peak EGT operation at maximum temperature, and maximum heat input for the process. The absence of excess oxygen in the exhaust gases, precluding outside air induction into the dryer vessel, the absence of exposed flame, and operation at the temperature set forth herein prevents significant oxidation of the algae in the dryer vessel, preserves the maximum nutrient value in the algae for containment in the end product, prevents the danger of fire damage to the equipment, and provides an operation safe from flash fires in the dryer vessel. The absence of excess fuel in the exhaust gases prevents the exhaust gases from being a source of hydrocarbons that must be scrubbed from the vapor effluent from the operation of this disclosure before being released into the atmosphere. The term "gas turbine" is used herein to mean and include any turbine engine having a compressor turbine stage, a combustion zone, and an exhaust turbine stage that is capable of producing exhaust gas temperatures of at least 500°F, preferably at least about 700°F, more preferably at least about 900°F, and most preferably greater than about 1,000 0 F. Gas turbines are the heat source preferred for use in this disclosure because of their efficient operation and high heat output. The gas turbine generator is further preferred for use in this disclosure due to the production of energy by the generator, which energy can be utilized or sold to improve the economics of the operation of the system of this disclosure. The generator will typically be an electric generator due to the convenience of using and/or selling the electricity produced. However, the generator can be any other type of energy generator desired, such as a hydraulic pump or power pack that can drive hydraulic motors on pumps, augers, conveyors and other types of equipment in the system of this disclosure or equipment in other nearby operations. The heat requirements and the system economics will determine whether a gas turbine or gas turbine generator is used. If it is desired to have higher temperature exhaust gases and higher heat output from a given smaller size gas turbine, it may be desired to use a gas turbine instead of a similar size gas turbine generator. Compared to the gas turbine, the gas turbine generator further expands and cools the exhaust gases in absorbing energy to drive the generator, where in a gas turbine that energy is contained in higher temperature gases available for use in the dryer vessel of this disclosure. This can be an option when it is economically more important in the practice of this disclosure to have small (truckable) high temperature units than to have the revenue stream or economic benefit of the electricity or other energy production by the gas turbine.
The gas turbine or gas turbine generator useful in this disclosure can be fueled from any available source with any suitable fuel for the particular gas turbine and for the process equipment designed according to this disclosure. Fuel sources for the turbine include, for example, sweet natural gas, diesel, biodiesel, ethanol, kerosene and jet fuel, methane, propane, butane, hydrogen, and biogas and bioliquid fuels (such as methane, oils, diesel and ethanol).
Examples of commercially available gas turbines and gas turbine generators useful in the present disclosure include the following (rated megawatt (MW) outputs are approximate): Rolls Royce Gas Turbine Engines Allison 501- KB5, -KB5S or -KB7 having a standard condition rated output of 3.9 MW; European Gas Turbines Tornado having rated output of 7.0 MW; Solar Mars 90 having rated output of 9.4 MW; Solar Mars 100 having rated output of 10.7 MW; Solar Tarus 60 having rated output of 5.5 MW; and Solar Tarus 70 having rated output of 7.5 MW. For a nominal product output capacity of 2.5 metric tons/hr (2,500 kg/hr), a gas turbine generator size of about 4 MW can be used, depending on the heat insulation and heat recovery efficiencies designed into the overall system. For small single semitrailer or truck systems, the units may be scaled smaller. For smaller product output systems, such as a 0.3 metric ton/hr product output, small gas turbines, such as Solar Saturn 0.8 MW, Solar Spartan 0.2 MW, or Capstone 0.5 MW or 0.3 MW generators, can be used depending on system efficiencies and required heat input ranges. It will be recognized that systems according to this disclosure can also be designed to utilize the exhaust gas heat from reciprocating engines, such as gasoline or diesel generators. Such small systems can be used at temporary sites, such as ships or oil drilling platforms.
The dryer vessel employed in this disclosure can be any type or configuration that is suitable for drying the algae available and that can be adapted for receiving the gas turbine exhaust gases and receiving the algae without allowing a significant amount of outside air to enter the drying chamber in the dryer vessel where the exhaust gases contact the algae. The objective of the design of the gas turbine exhaust connection to the dryer vessel for purposes of this disclosure is to preclude any significant outside air from entering the dryer vessel to help prevent significant oxidation of the algae. As previously pointed out, this is to preserve the organic matter, carbonaceous and/or nutrient values present in the algae, to prevent fires, and to provide a safe operation. As used in this disclosure it is preferred and expected that the turbine will be operated at a conventional ratio of fuel to combustion air in order to produce the most efficient exhaust gas temperature (EGT) for the dryer vessel and to produce gases entering the dryer vessel that contain a minimum of free oxygen. It will be recognized by those skilled in the art from the disclosure of this disclosure, that alternate sources of hot gases other than a gas turbine can be used and connected to the dryer vessel, such as the exhaust from conventional oil or gas burners and reciprocating engines, provided they are operated at conventional combustion ratio conditions to minimize free oxygen, or at stoichiometric ratio for no free oxygen in the exhaust, and are connected to the dryer vessel in a fashion that precludes significant outside air from entering the dryer vessel in order to preclude significant oxidation. Of course, such an alternate and additional source of hot gases can optionally be connected to the dryer vessel according to this disclosure, and be used to supplement the exhaust gases output of the gas turbine in order to provide additional heat input capacity for the dryer vessel if needed for start up, shut down, surge load conditions, or for backup in the event the gas turbine goes offline.
Exclusion of outside air is preferred for economic efficiency as well, because heating excess or outside air along with heating the algae reduces the efficiency of the process. It will be recognized that the operation of the dryer vessel is normally to dry the algae, but it is to also achieve the high temperature heating of the algae.
The types of dryer vessels that can be used in this disclosure are, for example, the following: a rotary drum with or without internal scrapers, agitation plates and/or paddles; a stationary "porcupine" drum dryer with or without scrapers and/or agitator plates and/or paddles; a triple pass stepped drying cylinder or rotary drum dryer systems with or without scrapers and/or agitator plates and/or paddles; rotary drum dryer systems with or without steam tubes and with or without scrapers and/or agitator plates and/or paddles; turbo-dryer or turbulizer systems; conveyor dryer systems with or without scrapers and/or agitator plates and/or paddles; indirect or direct contact dryer systems with or without scrapers and/or agitator plates and/or paddles; tray dryers; fluid bed dryers; and evaporator systems.
Examples of commercially available dryer vessels useful in or that can be adapted for use in this disclosure include: Scott AST Dryer™ Systems; Simon Dryer Ltd. drum dryers; Wyssmont Turbo Dryer systems; Duske Engineering Co., Inc. Energy Unlimited drying systems; the Onix Corporation dehydration systems; International Technology Systems, Lie. direct or indirect dryer systems;
Pulse Drying Systems, Inc.; and MEC Company dryer systems. Further examples of dryer vessels useful in or that can be adapted for use in this disclosure are disclosed in U.S. Pat. No. 5,746,006 to Duske et al., and U.S. Pat. Nos. 5,570,517 and 6,367,163 to Luker, the disclosures of which are incorporated herein by reference in their entirety.
As noted above the "dryer vessel" does not necessarily always function primarily as a dryer by removing moisture from the algae in the system of this disclosure. The dryer vessel also functions as the thermal treatment/conversion/alteration vessel or oven in which the algae are heated to sufficient temperatures for sufficient times to produce the desired final materials and products as disclosed herein. In addition, the dryer vessels need not provide direct contact of the turbine exhaust gases or other heat source and the algae, but can provide indirect heating of the algae to achieve the drying and/or thermal treatment/conversion/alteration desired according to this disclosure. In either direct or indirect heating, the system is controlled so that no significant oxidation and no significant pyrolysis of the algae takes place.
Another aspect of the dryer vessel adapted for use in this disclosure is that the dryer vessel preferably also functions as the silencer or muffler for the gas turbine or other engine providing the hot exhaust gases. It is well known that gas turbines (essentially jet aircraft engines) produce a high level of noise impact on the nearby environment. Stationary gas turbines used for electric power production or other purposes are usually required by local, state, and federal regulations to have silencers installed to muffle the noise of the exhaust of the gas turbine to acceptable levels. Such silencers have the economic disadvantages of cost and creating back pressure on the gas turbine exhaust, which reduces the efficiency of the gas turbine operation. One advantage provided by this disclosure, due to the connection between the gas turbine exhaust and the dryer vessel being closed to outside air, is that the dryer vessel functions effectively as a silencer for the gas turbine. This is at least in part a result of the internal configuration construction of the dryer vessel acting in combination with the presence of the high water content algae, which combination is effective in absorbing and muffling the gas turbine exhaust noise. This is also due to the downstream end of the dryer also being closed to the atmosphere, because the steam and off gases from the dryer vessel are collected for condensation, cleaning, recycling, and for heat recovery in the downstream processing in a closed system before being vented to the atmosphere. It will be apparent to one skilled in the art that capability for venting at various points in the process and the equipment system can be desirable, and the capability of operating as a closed system having only final product output and clean exhaust gas venting is also desirable. The turbine exhaust optionally can be partially or temporarily wholly diverted to other downstream units, bypassing the dryer vessel, when needed for supplemental heat. Another advantage provided by this disclosure is that the steam and off gases can be pulled from the discharge end of the dryer vessel by an appropriate fan, vent blower, etc., to provide a reduced pressure at the upstream entrance of the dryer vessel, thereby reducing the back pressure on the turbine exhaust. This increases the efficiency of operation of the gas turbine and is made possible because the connection between the gas turbine exhaust and the dryer vessel is not open to outside air. It will be understood that the commercial system design may include a vent or even a conventional silencer connected by tee or other configuration into the connection between the gas turbine exhaust and the dryer vessel for use during startup, shut down, or upset operation, but would not be employed in the normal operating configuration for the process and apparatus of this disclosure as described above. To achieve best efficiency of operation of this disclosure, it is preferred that the connection between the gas turbine exhaust and the dryer vessel inlet have no obstructions in order to deliver the exhaust gases to the dryer vessel with a minimum of heat and energy loss between the gas turbine and the dryer vessel. It will also be recognized from this disclosure that the operation of a gas turbine generator will preferably be controlled for optimal efficiency or economics for the algae drying, thermal conversion, chemical alteration, and other processing needs, which may not be the optimal or best gas turbine operating conditions for electricity production. The electricity production is a cost recovery revenue stream for the system, but the overall economics of the operation of this disclosure may be better under gas turbine operating conditions that favor optimum exhaust heat output for efficient dryer vessel operation and downstream production of products having desired properties and disfavor electricity production. Determination of such operating conditions for a particular installation of this disclosure will be apparent to one skilled in the art following the teachings herein. Gas turbine control systems of this type are disclosed in commonly assigned copending U.S. patent application Ser. No. 10/894,875, filed on JuI. 19, 2004, the disclosure of which is incorporated herein by reference in its entirety. The operating conditions and procedures for the dryer vessel will be apparent to one skilled in the art following the teachings herein of the disclosure of this disclosure. The typical turbine exhaust gas temperature entering the dryer vessel will be in the range of about 500 0 F to about l,500°F, depending on moisture and other content of the algae and the desired condition of the fertilizer or soil builder material output from the dryer vessel. In smaller systems with smaller engines, the inlet exhaust gas temperature can be as low as about 300 0 F or about 350 0 F. A preferred range is from about 600 0 F to about 1200 0 F, and it is more preferred that the inlet temperature be at least about 65O 0 F, and most preferably at least about 700 0 F. The temperature and flow rate of the gas entering the dryer vessel will depend in part on the moisture content and other properties of the algae. Higher moisture content will obviously generally require higher inlet gas temperatures to reduce the moisture content. It is believed that an additional efficiency is achieved in the systems of the present disclosure where high moisture content algae are contacted with high temperature gases. Such contact causes the formation, sometimes instantly, of superheated steam as the moisture comes out of the algae, then that superheated steam heats and drives the moisture out of adjacent algae. It is believed that this mechanism is responsible for quick drying of the algae to a low moisture content so that the remaining residence time of the algae in the dryer vessel contributes to the desired thermal treatment/conversion/alteration or "cooking" thereof according to this disclosure.
As further disclosure and illustration of the processes, systems, and equipment of this disclosure, reference is made to the schematic flow chart of FIG. 1. Ih the exemplary process illustrated, gas turbine generator unit 100 comprises a gas turbine 101 and electric generator 102. The gas turbine has an air intake filter 104 and fuel feed 103. If desired, optional bypass exhaust silencer 106 can be included for startup, shutdown, or upset conditions during those times the gas turbine is running but the exhaust gases cannot be directed into the dryer vessel. However, dryer vessel 200 will function as the silencer in the normal operation of the system of this disclosure. Alternatively, instead of a silencer, the exhaust gas bypass around the dryer vessel can be directed to any appropriate downstream unit, such as separator 208, which can provide a temporary silencer function. This arrangement eliminates the cost of a separate silencer and the space required for a separate silencer, which are important considerations for the portable, truck-mounted systems. The gas turbine 101 exhaust is connected to the dryer vessel 200 by connector 105. An optional air inlet (not shown) can be included for dryer vessel 200 in connector 105 or elsewhere for purging the dryer vessel or the system, for startup or shutdown or for other reasons, particularly when either the exhaust gases or the algae is not present in the dryer vessel 200. However, when both are present, any such air inlet is closed and not used in order to substantially preclude introduction of air into the dryer vessel and to preclude significant oxidation of materials being processed in the dryer vessel 200. Optional burner 107 can also be included to provide supplemental heat source and combustion gases for the dryer vessel, which can be provided for input in connector 105 or elsewhere. The optional supplemental heat source may be useful during startup, shutdown, process upset, turbine outage, or to maintain desired throughput when a peak load or unusually high water content feedstock is encountered.
The harvested algae are typically introduced into the system by mechanical means pneumatic conveyor and/or front end loader 201, which drops the algae into a separator, mixer, chopper unit 202. The algae can be further mixed and foreign objects separated in screw conveyers 203, 204 then fed to the dryer vessel 200 through 215. The stock can also be pre-mixed or conditioned for desired uniformity prior to loading into this system by conveyor 201, e.g., in storage windrows that can be combined and mixed. The output from the dryer vessel 200 is transferred by conduits 205, 206 to separator 208 where the solids and gases are separated. The gases pass through 209 and blower 210 to the atmosphere via 211 or to other downstream processing via 212. Blower 210 can be operated to lower the pressure in separator 208 and in the dryer vessel 200, which will reduce the water boiling point in the dryer vessel and will reduce the back pressure on the turbine exhaust and increase the turbine output and efficiency. Alternatively, blower 210 can be operated to maintain increased pressure in the dryer vessel for higher temperature treatment, conversion, or "cooking" of the algae, if desired. The output from dryer vessel 200 can pass through optional heat exchanger 207 for recovery of process heat for use downstream or in preheating the algae or turbine intake air. The solids output from separator 208 passes to ball mill or hammer mill 300 via conduit, conveyor or auger 301 and optional mixers and conditioner 302. FIG. 2 illustrates one configuration of the system of this disclosure in the form of skid mounted, truck mounted, ship mounted, platform mounted, or rail car mounted units. The first unit 700 comprises the gas turbine 101 and generator 102. The second unit 701 comprises dryer vessel 200 and separator 208. The dryer vessel 200 has algae inlet 215 and is connected to the gas turbine exhaust by connector 105 when stationary and in operation. The third unit 702 comprises the processing equipment desired for a particular operation, such as the ball mill. The product output is conveyed by 501 to storage units 500 or to ship 502 or other vessels for transport. Optional equipment can also include units for bagging and other packaging of the final product for various markets.
FIG. 3 A is a plan view and FIG. 3B is an elevation view of another portable configuration of the system of this disclosure wherein all operating units are mounted on platform 800. Gas turbine unit 100 exhaust is connected to dryer vessel 200 by connector 105. Dryer vessel 200 has algae inlet 215 and is connected to separator 208 by conduit 206. Separator 208 is connected to vapor/air cleaner separator 600 by conduit 209 and separator 600 vents to the atmosphere by vent 602. The bottom outlet of separator 208 is connected via conduit 301 to ball mill unit 300. The outlet of ball mill unit 300 is connected via conduit 312 to pelletizer unit 400, which is connected to product cleaning unit 415 by conduit 414. Cleaning unit 415 has product outlet 416. Not shown in FIGS. 2, 3 A and 3B is an optional enclosure for each skid-mounted or truck-mounted unit to enclose the entire unit for weather protection and for noise attenuation.
FIG. 4 is a schematic process flow chart of some of the optional systems of this disclosure. In a preferred operation of this disclosure, the gas turbine generator 101/102 produces electric power 905, which can be either sold to the local power company 906 or otherwise distributed.
According to one embodiment the algae are filtered or separated 900 and pre- washed 901 before being loaded into the dryer vessel. A filter or separating step can be used to remove undesirable materials that are collected in the harvesting process. A pre-washing step can also be used to preprocess the algae and remove unwanted materials. It should be appreciated that filtering, separating, and washing steps can also occur after the material exits the dryer vessel 200.
The exhaust gases from the gas turbine 101 are passed to the dryer vessel 200 by a connection 105 that precludes outside air from entering the dryer vessel. As disclosed herein, the system is operated so that the oxidation of the algae in the dryer vessel 200 and elsewhere in the system is minimized and substantially avoided. The dryer vessel 200 also serves as a silencer for the gas turbine. An optional bypass 908 can be provided so the exhaust gases can be sent to downstream equipment, such as separators/condensers 208, to silence the gas turbine exhaust when the dryer vessel is offline, and to clean the exhaust gases before release into the atmosphere during such temporary operation. Or, the bypass 908 exhaust gases can be sent to a heat exchanger for water heating or other climate control or process energy requirements. This bypass eliminates the cost of having a separate silencer to satisfy noise restrictions on the gas turbine when the dryer vessel is offline, and provides a more compact design for portable or platform mounted units.
As will be apparent to one skilled in the art, multiple gas turbines, other engines and/or burners of the same or varying types and sizes can be manifolded together to feed multiple dryer vessels of the same or varying types and sizes in a single installation. This can be done to not only provide increased processing capacity but also to provide operational flexibility for processing varying feedstock loads and for performing equipment maintenance without shutting down the operation.
According to various embodiments, the harvested wild algae can be processed to ethanol, biodiesel, paper, and feed/food products. Example methods of converting algae to fuel are disclosed in: US 7,135,308 titled Process for the Production of Ethanol from Algae; US 2007/0202582 titled Process for the Production of Ethanol from Algae; US 4,351,038 titled Oil Products from Algae; and US 2007/0048848 titled Method, Apparatus and System for Biodiesel Production from Algae, which are all hereby incorporated by reference in their entirety. An example method of converting algae to paper is disclosed in US 5,500,086 titled Method for Producing Pulp from Green Algae, which is hereby incorporated by reference in its entirety. Example methods of converting algae to food/feed products are disclosed in US 5,715,774 titled Animal Feedstock Comprising Harvested Algal Turf and a Method of Preparing and Using the Same, and US 7,208,160 titled Process of Treating Sea Algae and Halophytic Plants, which are all hereby incorporated by reference in their entirety. In some embodiments, the algae are mixed with corn products and other substrates to provide the desired feed mix.
While we have illustrated and described various embodiments of this disclosure, these are by way of illustration only, and various changes and modifications may be made within the contemplation of this disclosure and within the scope of the following claims.
The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.