Carbon dioxide generation and dispensing device and method of production

A CO2 generating and dispensing device having container with a first space for receiving oxalic acid and water, and a second space for receiving a CO2 generator which generator is attached to a lid. The lid secures to the container. Two conductive rods extend above the lid and are attached to the CO2 generator. Electric current is applied to the rods which initiates the CO2 generation. Generated CO2 rises from the second space and out a discharge vent on the lid. An hose attached to the discharge vent direct the CO2 to a pre-determined destination.

BACKGROUND

This device relates to an improvement in the generation of carbon dioxide, and more particularly to a self-sustaining, on-site generation of carbon dioxide.

Commercial carbon dioxide is widely used and is generally manufactured by separation and purification from carbon-dioxide-rich gases produced by combustion or by biological processes. It is also found in underground formations in some states. Carbon dioxide is also commercially available as high-pressure cylinder gas [about 300 psig], in refrigerated liquid form, or as a solid [dry ice].

Common uses of carbon dioxide include, among other uses, use in fire extinguishing systems, for carbonation of soft drinks and beer, freezing of food products, refrigeration and maintenance of environmental conditions during transportation of food products, enhancement of oil recovery from wells, materials production [such as plastics and rubber], and treatment of alkaline water, as a shield during welding where it protects the weld against oxidation, dry ice pellets for sand blasting surfaces without leaving residues, in the chemical processing industry such as methanol production, for priming oil wells to maintain pressure in the oil formation, for removing flash from rubber or plastic objects by tumbling with dry ice, for the creation of inert blankets or environments, for the prevention of fungal and bacterial growth, as an additive to oxygen for medical use, as a propellant in aerosol cans, and to aid in maintaining a level of 1000 ppm in green houses to increase production yields of vegetables and flowers, to name a few.

To meet the needs of these various applications, requiring from small quantities of carbon dioxide (less than a pound/day) to extremely large quantities (tons/day), carbon dioxide is available as a compressed gas requiring heavy cylinders, or a liquid under pressure available from tube or liquid trailers, or as solid dry ice.

Very small users rely on high pressure cylinders. Their distribution is generally conducted by locally-focused businesses that buy the gas in bulk liquid form and package it at their facilities. Small to medium size customers truck-in bulk liquid products that are then processed through evaporation to produce the gas. Larger customers' needs are often met with “tube trailers”, i.e., bundles of high-pressure cylinders mounted on wheeled platforms. Onsite” plants are usually installed by customers consuming more than 10 tons/day of the gas.

There is an increasing interest in user-owned, small, non-cryogenic gas generators, in many markets. Such generators are available for oxygen, hydrogen and nitrogen, but not for carbon dioxide. For example, small to medium size users of oxygen or nitrogen may find an economical supply alternative in pressure-swing-adsorption (PSA) plants. Or again, hydrogen and oxygen may be produced through electrolysis of water. High purity hydrogen may then be produced by purification of the stream by using palladium foil diffusers.

To-date, “on-site” economical carbon dioxide generators, such as are available for hydrogen and oxygen, do not exist, although the demand for carbon dioxide is substantial. Moreover, the benefits of these “on-site” generators are multiple. For example, generation on demand, as needed independence from suppliers and possible supply interruptions, cost-insensitivity to supply issues no need for pressure vessels, their storage and recycling, and the like.

To meet this need, applicant has invented an electrolytic process and methods to produce carbon dioxide from organic acids which were originally described in U.S. Pat. Nos. 6,780,304 and 6,387,228. Applicant has pursued the development of that generation technology by developing multiple electrochemical cells assembled in stacks to achieve production rates and volumes much larger than those described in these patents.

Continuing in this vein, applicant has now designed an entire, self-sufficient carbon dioxide generation system comprised of solar panels, an electronic control unit for the transfer of solar energy to a battery, an electronic control module controlling the current output to an electrochemical carbon dioxide generator [electrolyzer] such as disclosed in applicant's pending application, application Ser. No. 11/650,016 filed on Jan. 5, 2007, which is hereby incorporated by reference.

The preferred mode utilizes the carbon dioxide generator disclosed in applicant's pending application ['016] which comprises a stack of at least two electrochemical cells, though any on-site carbon dioxide generator suited for the intended purpose may be used. The targeted carbon dioxide generation rate was 12 Liters/hour (0.05 lb/hr) for a duration of 10 hours per day, however, the system has been designed to, and can, generate in excess of 45 L/hr (0.18 lb/hr).

To create the self-sufficient carbon dioxide generation system applicant first devised a novel process to produce solid oxalic acid [OA] toroidal “briquets” weighing about 2 kg. each for placement and use in the novel dispenser. This generation and dispensing device designed by applicant forms the primary subject matter of this current application. Assembling and placing four such toroidal briquets into the device would allow for autonomous system operation and carbon dioxide generation for about one month, provided adequate solar energy can be harvested to sustain operation.

These oxalic acid [OA] toroidal briquets are used as the source for carbon dioxide generation. Anhydrous OA contains as much as 97.7 wt % carbon dioxide and therefore is the preferred source though, in some instances, oxalic acid dihydrate [OA 2H2O] can also be used. As developed by applicant, each toroidal briquet has an external diameter of approximately 25 cm, an internal diameter of approximately 10 cm, a thickness of approximately 3.5 cm, and weighs approximately 2.1 kg. A single toroidal briquet is adequate to support operation, at the nominal 12L/hr rate, for up to 9 days. As many as four such toroidal briquets can be stacked up in applicant's generating and dispensing device.

It should be understood that the size and dimensions of the toroidal briquet can vary as can the dimensions of the generating and dispensing device to accommodate the varying sizes of the toroidal briquet.

The toroidal briquets are compact, solid OA that can be easily handled without undue precaution. The ability to stack these toroidal briquets is the key component of the sub-system which makes the generating and dispensing device the vital and indispensable component thereof. The generating and dispensing device has an inner chamber inside of which the carbon dioxide generator of my pending application ['615], one or more, may be housed and outside of which the toroidal briquets are stacked. An upstanding inner cylindrical wall [central pipe] extending from the floor of the generating and dispensing device up to approximately its top form a barrier between the carbon dioxide generator and the toroidal briquets. With current applied to the carbon dioxide generator and the desired carbon dioxide generation rate is set, the system will generate carbon dioxide without any human oversight, interface, or maintenance.

Through experimentation is has been shown that the system is capable of producing approximately 9.12 L/hr of carbon dioxide per amp. A current load of approximately 1.32 amps has been shown to be adequate to achieve the nominal carbon dioxide generation rate. A current load of approximately 3.29 amps has proven to be adequate to generate approximately 30 L carbon dioxide/hr.

Under these current loads the voltage applied to an electrolyzer, for example, holding 10 electrochemical cells, in series connection, is approximately 12 volts. Consequently, a 12-volt battery should be adequate for the entire system for adequate operation and uninterrupted and unsupervised carbon dioxide generation. The nominal power requirement should be between approximately 16 watts to approximately 40 watts for a maximum rate of production of approximately 30 L/hr of carbon dioxide. With the system operating for approximately 10 hours/day, the total daily energy required will be approximately 160 to 400 watt-hours.

The container of the generating and dispensing device is approximately 30 cm in diameter and approximately 16 cm high. The upstanding inner cylindrical wall [or central pipe] has a diameter which is smaller than the diameter of the inner diameter of the toroidal briquet. Given this configuration it can been seen that up to four toroidal briquets can be staked into the container. A lid is securely attached to the container. It has through holes for the stack terminals and the exhaust gas. The thick-walled container has been especially molded for this application. The toroidal briquets are to be located between the outer wall of the container and its upstanding inner cylindrical wall. As previously mentioned, this upstanding inner cylindrical wall is attached to the floor of the container and prevents the OA toroidal briquets from interfering with the extraction of the stack of toroidal briquets, should maintenance be required.

Before operation approximately 1-2 pints of water are poured into the container to initiate the process to dissolve the bottom most OA toroidal briquet.

The system has been designed to operate during night-time hours. Therefore any solar-generated energy is to be stored for nighttime consumption. The battery described above is selected on the basis of its ability to store sufficient energy for 1-2 days of operation during cloudy days. The battery voltage is selected for its compatibility with solar panels and the current load required by the electrolyzer [carbon dioxide generator]. As noted above a 12-volt, 55 A-hr battery is adequate for the nominal generation rate. The battery selected is a 490T SunXtender. A larger battery such as a 560T or 690T model with storage capacity of 63 and 79 A-hr will be needed for the sustained operation at 30 L/hr.

Two control units are necessary to the operation of the system as described; a conventional commercially-available charge controller and a commercially-available modified load current controller. A typical charge controller, such as a Steca PR 110 unit is suitable for the intended purpose. Its main function is the regulation of current and voltage between panels and the battery to optimize battery charging without overload, and the like.

The load controller developed as part of this project provides current regulation from the battery to the electrolyzer [carbon dioxide generator]. The unit design is based on Linear Technology model LTC3780 Buck-Boost Controller, configured as a constant current source. The circuitry provides for efficient power conversion from battery to load while operating over a wide range of input voltages and load impedances. Presently the efficiency of either controller is estimated at approximately 90%. For energy efficient systems this could be increased by careful selection of certain components.

The primary source of energy contemplated is solar energy which is collected during the daytime and stored into a conventional commercially-available rechargeable battery. Surplus solar energy is dumped when the battery is fully charged. If adequate solar energy is not available, the load will extract energy mainly from the battery and progressively go dormant [the load current decreases] to protect the battery from deep discharge which would result in reduced life. The stability of the system will therefore depend on levels of insolation, battery capacity, and load demand.

During the months of interest for carbon dioxide use, and therefore generation [generally late Spring to early Fall] daytime exceeds 10 hours, insolation is high, and the conditions are optimum for the system. In the event of continuous cloud coverage for up to two days, the system is de-rated only producing partial carbon dioxide output. A daily operating duration of the generator of 10-12 hours is anticipated.

The generation rate can be selected manually by operation of a rotary switch at varying discrete values of 0, 12, 18, 24, and 30 L./hour. Once the rate is set, generation of carbon dioxide is quasi-instantaneous. The rates, however, can be changed at will.

During operation, toroidal briquet is dissolved and the saturated toroidal briquet solution is decomposed into carbon dioxide and hydrogen. The carbon dioxide gas evolves through the apertures in the inner wall [central pipe] and is released through the discharge vent located at the approximate center of the lid. The lid also can hold means to scrub the gas phase and/or means to hold a secondary releaser that will continuously feed a pheromone, such as octenol, into the exhaust stream as may be necessary or desired to attract insects.

The foregoing has outlined some of the more pertinent objects of the generating and dispensing device. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the generating and dispensing device. Many other beneficial results can be attained by applying the disclosed generating and dispensing device in a different manner or by modifying the generating and dispensing device within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the generating and dispensing device may be had by referring to the summary of the generating and dispensing device and the detailed description of the preferred embodiment in addition to the scope of the generating and dispensing device defined by the claims taken in conjunction with the accompanying drawings.

SUMMARY

The above-noted problems, among others, are overcome by the generating and dispensing device. Briefly stated, the generating and dispensing device contemplates a sealed container with an easily removable lid which, when initialized, begins generating carbon dioxide at a pre-determined rate without intervention. The container has an upstanding inner cylindrical wall extending upward from the floor defining a first space outside the upstanding inner cylindrical wall and a second space within the upstanding inner cylindrical wall.

The lid has a hollowed shaft extending downward which is adapted to seat into the second space defined within the upstanding inner cylindrical wall. Attached to the lid and in the hollow space inside the shaft is a carbon dioxide generator. One or more OA toroidal briquets are placed in the first space of the container. Water is dispensed into the first space such that the water covers the top of the bottom OA toroidal briquet.

Then the shaft, with carbon dioxide generator attached to the lid, is set into the second space and the lid secured to the container. At least two conductive rods are attached to the carbon dioxide generator and extend up and past the top of the lid. Current from outside is applied to the rods. Carbon dioxide gases are thereby generated and directed from the container through a discharge vent in the lid above the shaft space and is captured for desired use.

The foregoing has outlined the more pertinent and important features of the generating and dispensing device in order that the detailed description that follows may be better understood so the present contributions to the art may be more fully appreciated. Additional features of the generating and dispensing device will be described hereinafter which form the subject of the claims. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures and methods for carrying out the same purposes of the generating and dispensing device. It also should be realized by those skilled in the art that such equivalent constructions and methods do not depart from the spirit and scope of the generating and dispensing device as set forth in the appended claims.

DETAILED DESCRIPTION

Referring now to the drawings in detail and in particular toFIGS. 1 and 2, reference character10generally designates a carbon dioxide generation and dispensing device constructed in accordance with a preferred embodiment thereof. The device10has a container21with a floor25, an upstanding outer wall23, and an upstanding inner cylindrical wall33extending up from said floor25to a point below the top of the upstanding outer wall23referenced here as plane-K. A hollow first space24is defined between the upstanding outer wall23and the upstanding inner cylindrical wall33and a hollow second space34is defined within and inside of the inner cylindrical wall33.

The outer diameter of the first space24is referenced herein as D or diameter-D and its inner diameter is referenced herein as E or diameter-E. The inner diameter of this first space24, diameter-E, is also equal to the outer diameter of the upstanding inner cylindrical wall33.

A plurality of apertures37on the inner cylindrical wall33, near to the floor25, permit the free flow of matter to be described below.

A lid11securely attaches to, and covers, the container21. A conventional gasket or seal51is on the perimeter of the upstanding outer wall23providing a sealing component between the upstanding outer wall23and the lid11. The lid11is secured to the container21by fastening means between the two. As illustrated the fastening means comprise a first externally threaded fastening component29connected to, and extending above, the upstanding outer wall23and a cooperating second internally threaded component16.

As illustrated inFIG. 2, there are a plurality of externally threaded fastening components29around the upstanding outer wall23. Additionally, there are a plurality of corresponding apertures19on the lid11which register with, and fit onto, each of the externally threaded fastening components29. The seal51also has a plurality of corresponding apertures59which are in alignment with the corresponding apertures19on the lid11and with externally threaded fastening components29. As illustrated here, the internally threaded components16are conventional wing-nuts. This configuration facilitates securing the lid11to the container21and further facilitates its removal from the container21when, and as, necessary.

A hollow cylindrical shaft13extends downward from the bottom surface of the lid11which, when inserted into the second space, will extend to a point above the floor25. The outer diameter of the cylindrical shaft13, referenced herein as A or diameter-A, is less than the diameter of the second space34, referenced herein as B or diameter-B, thereby permitting the cylindrical shaft13to ride into the second space34. Diameter-B also equals the inner diameter of the inner cylindrical wall33.

Cylindrical shaft13is provided with a port18to equalize the internal pressure withing the device10. One or more such ports18may be located anywhere on the cylindrical shaft13. To facilitate the pressure equalization process, however, it is best that such ports18be above the top of the inner cylindrical wall33, plane K.

A hollow shaft space14is defined within the cylindrical shaft13. The shaft space14has a diameter referenced as G or diameter-G which also is the inner diameter of the cylindrical shaft13.

The lid11had a discharge vent17for directing the release and dispensing of pre-determined amounts of the carbon dioxide gas being generated within the device10. The discharge vent17is in communication with the shaft space14. As illustrated, the discharge vent17is relatively centrally located on the lid11, however, it may be located anywhere on the lid provided the discharge vent17remains in communication with the shaft space14such that gases generated within the device10are directed to and intended to be released only through the discharge vent17.

Typically an external hose or conduit53is removably attached to the discharge vent17to thereby convey the releasing gases to a desired destination. The lid11also has a pressure relief valve15which will permit generated gases within the device10to escape should the pressure within reach a pre-determined level.

The container21somewhat resembles an angel-food-cake pan or a bundt-cake pan. The inner cylindrical wall33is generally centrally located and rises upward from the floor25. An toroidal briquet60, with its donut-like shape, fits around the inner cylindrical wall33and, being the first toroidal briquet60placed therein, will rest on the floor25in the first space24.

FIG. 1illustrates four toroidal briquets60stacked into the first space24. A carbon dioxide generator41[electrolyzer] with its generator-housing component40seats into the second space34such that the bottom of the generator41generally should not be touching the floor25. The bottom plane of the generator41is reference character J. The generator41should generally be slightly above the floor25. It may, however, touch the floor25, but it is preferred that it not to thereby allow the OA, when in solution, to freely flow underneath the generator41.

The generator-housing component40holding the generator41comprises a guide plate45having a plurality of apertures47to permit generated gases to pass therethrough and up and out the discharge vent17. The diameter of the guide plate is referenced herein as H or diameter-H and diameter-G [diameter of the shaft space14] is greater than diameter-H.

At least two retaining rods42A,42B are affixed to the guide plate45with ends of the retaining rods42A,42B extending above and below the guide plate45. The retaining rods42A,42B have external threading and are secured to the guide plate45by any suitable fastening components such as, but not limited to, nuts46with internal threading compatible with, and to, the external threading of the retaining rods42A,42B.

The upper ends of the retaining rods42A,42B register with apertures12A,12B on the lid11and pass through and extend above and beyond the lid11. The retaining rods42A,42B must be produced using a conductive material for reasons to be explained below.

As illustrated, the generator41is attached to the retaining rods42A,42B. The guide plate45is attached to the retaining rods42A,42B at a point above the generator41. The guide plate45is firmly secured in position by use of a nut46above the guide plate45and a nut46below the guide plate45. The guide plate45, with its diameter-H slightly smaller than the shaft space14diameter-G, eases and guides the extraction and insertion process of the generator-housing component40onto the lid11.

Before this generator-housing component40is set into the lid11by inserting the retaining rods42A,42B through the respective lid apertures12A,12B, one nut46is threaded onto each retaining rod42A,42B and height-adjusted such that the bottom of the generator41, when the lid11with generator-housing component40is set onto the container21, does not contact the floor25and rests at approximately plane-J. When this height-adjustment is completed the generator-housing component40is firmly secured to the lid11first by placing a sealing ring48[such as, but not limited to, a rubber or other suitable washer] against the lid11followed by threading a nut on each of the retaining rods42A,42B extending above the lid11. The sealing rings48will prevent gases generated within from escaping at that connection.

Several such lid-to-generator attachments should be pre-made so that a user need only remove the lid structure [lid11with generator41attached thereto as described above] of a processing unit and replace it with another lid structure.

This configuration makes replacing a worn or defective generator41an easy operation requiring little or no skill. The user merely removes the external hose53and unfastens the wing nuts16which secure the lid11to the container21. The lid11, with attached generator-housing component40and generator41attached, are removed with the lid. A previously pre-made lid-to-generator attachment is placed into the down the second space34and easily guided into place. No adjustments will be necessary as all such pre-made lid-to-generator attachments have been pre-made to approximately equal specifications.

FIG. 1illustrates four toroidal briquets60inside the first space24. Before the lid11, with generator41attached, is secured to the container21, water is placed into the first space24approximately up to the top surface of the generator41[illustrated here as the Water Level]. The lid11is then secured to the container21and the external hose53attached to the discharge vent17.

In the event excess water is placed into the container21, a discharge valve27on the bottom of the container21, in communication with the second space34, permits the user to easily discard any unwanted water by turning the discharge valve27to an open position, discharging water until the amount desired is left remaining, and turning the discharge valve27to the closed position. Similarly, use of the discharge valve27after carbon dioxide generation has completed, facilitates removal of any remaining aqueous OA solution from the container21.

The toroidal briquet60is donut-like with a hole63in the approximate center. The diameter of the hole63is referenced as C or diameter-C which also is equal to the inner diameter of the toroidal briquet60. The outer diameter of the toroidal briquet60is referenced as F or diameter-F. This outer diameter, diameter-F, is less than the outer diameter of the first space24, diameter-D and the diameter of the central hole63of the toroidal briquet60, diameter-C, is greater than the inner diameter of the first space24, diameter-E.

After one or more toroidal briquets60are placed into the first space24and water dispensed up to the approximate top of the generator41, the lid11secured to the container21, and an external hose53attached to the discharge vent17, a current is then applied to the retaining rods42A,42B to begin the generation and capture process.

Though wing nuts16and common internally threaded nuts46have been described with particularity herein as fastening components, it should be understood that any fastening component, suitable for the intended purpose, will suffice.

Additionally, the diameters disclosed herein are such that a relatively loose-fit is made between the outer diameter [diameter-A] of the shaft13and the diameter [diameter-B] of the second space34to preclude or best minimize escaping of any materials from the first space24into the second space34through any means other than as intended; i.e., through the plurality of apertures37on the upstanding inner cylindrical wall33. An equally loose-fit is envisioned between the guide plate45[with diameter-H] and the diameter of the shaft space14[diameter-G] for the purpose of facilitating and easing the insertion and removal of the generator-housing component40from the lid11and the shaft space14.

As described in the Background, which is incorporated herein by reference, the device, as part of the system, will continue to generate carbon dioxide, passing it through the device10as basically illustrated by the arrows inFIG. 1, for up to four weeks without need for human intervention.

The present disclosure includes that contained in the present claims as well as that of the foregoing description. Although this generating and dispensing device has been described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms has been made only by way of example and numerous changes in the details of construction and combination and arrangement of parts and method steps may be resorted to without departing from the spirit and scope of the generating and dispensing device. Accordingly, the scope of the generating and dispensing device should be determined not by the embodiment[s] illustrated, but by the appended claims and their legal equivalents.

Applicant has attempted to disclose all the embodiment[s] of the generating and dispensing device that could be reasonably foreseen. It must be understood, however, that there may be unforeseeable insubstantial modifications to generating and dispensing device that remain as equivalents and thereby falling within the scope of the generating and dispensing device.