SYSTEM AND METHOD FOR CUSTOMIZING A FUEL PELLET

FORMULATION

CROSS REFERENCE TO RELATED APPLI ATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 61/004,478 filed November 28, 2007 entitled SYSTEM AND METHOD FOR CUSTOMIZING A FUEL PELLET FORMULATON, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Oil and coal are commonly used for heating. However, increasing costs and environmental concerns related to fossil fuels have led to an increased demand for alternative heating fuels. One such alternative is pelleted fuel.

[0003] Hardwood pellets can provide sufficient heat to be an efficient fuel. However, pelleted hardwood fuels face some of the same limitations as fossil fuels. For instance, hardwood trees that are harvested take years to replace with new growth. Also, the increased efficiencies achieved in the lumber and paper industries place constraints on the amount of hardwood scrap that is available for pelleting. Hardwood also has a high lignin content (e.g., typically at least about 25 wt.%). High lignin content can result in the production of tar-like residues when the fuel is burned. This may necessitate processing of hardwood materials to remove a portion of the lignin content prior to being used to form a fuel pellet.

[0004] Fuel pellets may also be formed using ingredients other than or in addition to hardwoods. These fuel pellets may be created using a variety of available materials including, for example, shelled corn and hulled wheat. These fuel pellets may be produced by processing a variety of materials to generate the fuel pellets.

[0005] There is a need for a system and method for generating a fuel pellet formulation in view of a fuel pellet criteria. There is further a need for such a system configured to generate the fuel pellet formulation to produce fuels that are renewable and in adequate supply.

SUMMARY OF THE INVENTION

[0006] The present application is directed to a system and method for generating a formulation for fuel pellets formed from a mixture which includes an agricultural biomass. Suitably, the fuel pellets include substantial amounts of agricultural biomass having a relatively low lignin content. The fuel pellets may be specifically formulated to meet a defined criteria, e.g., to have a low ash content, good pellet durability (e.g., as determined by their pellet durability index), heating values comparable to conventional hardwood fuel pellets, etc. In some embodiments, it may be useful to formulate the fuel pellet such that it has an ash content with composition and/or characteristics comparable to that of fly ash.

[0007] One embodiment of the present system relates to a system for determining formulation of a pelleted fuel. The system includes a first memory portion configured to store fuel ingredient data representative of fuel ingredients, a second memory portion configured to store at least one evaluation criteria constraining the generation of the formulation data, and a data processing circuit in communication with the first and second memory portions and configured to generate a fuel pellet formulation representative of a combination of fuel ingredients, the fuel pellet formulation data being generated by the data processing circuit based upon the fuel ingredient data and evaluation criteria. The formulation system may also include a formulation system user interface, a fuel pellet formulation engine, and/or a back end interface. Further, each engine or interface may alternatively be implemented using multiple, distributed systems. In some embodiments, the formulation system may also be configured to allow manufacturers or producers of pelleted fuels to access consulting services using system.

[0008] Another embodiment of the invention relates to a method of determining formulation of a pelleted fuel. The method includes receiving fuel ingredient data representative of fuel ingredients, receiving at least one evaluation criteria constraining the generation of the formulation data, and generating a fuel pellet formulation representative of a combination of fuel ingredients. The fuel pellet formulation data is generated based upon the fuel ingredient data and evaluation criteria.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 shows a networked system for generating and providing a fuel pellet formulation, according to an exemplary embodiment.

[00010] FIG. 2 depicts the fuel pellet formulation engine of FIG. 1 shown in further detail, according to an exemplary embodiment.

[00011 ] FIG. 3 is a flowchart 300 illustrating a method for generating a fuel pellet formulation, according to an exemplary embodiment.

[00012] FIG. 4 shows a graph of BTU/lb (dry matter basis) for actual lab analysis compared to formulated predicted values for the eight fuel pellet formulations shown in Table IV.

[00013] FIG. 5 shows a graph of BTU/lb (as is basis) for actual lab analysis compared to formulated predicted values for the eight fuel pellet formulations shown in Table IV.

[00014] FIG. 6 shows a graph of ash content (dry matter basis) for actual lab analysis compared to formulated predicted values for the eight fuel pellet formulations shown in Table IV.

[00015] FIG. 7 shows a graph of ash content (as is basis) for actual lab analysis compared to formulated predicted values for the eight fuel pellet formulations shown in Table IV.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[00016] A system and method for customizing a fuel pellet formulation is described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of system and method. It will be evident, however, to one of ordinary skill in the art that the exemplary embodiments may be practiced without these specific details. In other instances, structures and devices are shown in diagram form in order to facilitate description of the exemplary embodiments.

[00017] Referring now to FIG. 1 , a networked system 100 for generating and providing a fuel pellet formulation is shown, according to an exemplary embodiment. System 100 includes

a fuel pellet formulation system 1 10 and a plurality of computer systems 120 used by users to access the formulation system. The formulation system 110 may be implemented on one or more host computers and may be accessible to the computer systems 120 by way of a network, such as the Internet 108. Although system 1 10 is shown as including specific systems arranged according to a specific configuration, it should be understood that system 1 10 may include more, fewer, and/or a different configuration of systems to perform the functions described herein.

[00018] The formulation system 110 includes a formulation system user interface 1 12, a fuel pellet formulation engine 114, and a back end interface 116. Interface 112, engine 114 and interface 1 16 in formulation system 110 may be implemented using separate computing systems (e.g., separate servers) as shown or may be implemented as processes on a single computing system. Further, each engine or interface may alternatively be implemented using multiple, distributed systems.

[00019] Formulation system user interface 112 is a computing system configured to provide a front-end interface to formulation system for users desiring to use the functions of system 110, such as generating a fuel pellet formulation, providing ingredient information, determining ingredient pricing and availability, determining one or more evaluation criteria, etc. as described herein. According to an exemplary embodiment, user interface 112 is configured to implement a plurality of web-based interfaces configured to allow users to access these functions. User interface 112 may also be configured to implement supportive functionality related to these transactions such as security functions, system help functions, ingredient searching functions, ingredient source searching functions, etc.

[00020] Fuel pellet formulation engine 114 is a computing system configured to generate a fuel pellet formulation. Generating a fuel pellet formulation includes generating a suggested combination of fuel pellet ingredients based one or more evaluation criteria. The evaluation criteria can include least cost, heating value, ash content, integrity to reduce the amount of fine particles released during burning, etc. as further below with reference to FIG. 2.

[00021] Back end interface 1 16 is a computing system configured to allow an implementer of system 1 10 to perform maintenance and implementation functions on system 1 10. Maintenance and implementation functions may be implemented using computer code configured to affect the operation of system 1 10. Exemplary functions may include performing

database maintenance, performing computer code updates, implementing changes to the interfaces of interface 1 12, implementing financial functions, updating ingredient listings, etc.

[00022] Computing systems 120 are configured to enable users to access the functionality of system 110, provide information to system 1 10, obtain formulation results from system 110, etc. In exemplary embodiments, the computing systems 120 may comprise personal computers, portable handheld devices (e.g., cellular telephones, PDA devices, portable e-mail devices), and other types of devices enabling users to view, edit, or otherwise access the information contained in the messaging system 110. Some embodiments may include other systems in addition to or in place of the computing systems 120 to allow the user to interact with the formulation system 110.

[00023] According to an exemplary embodiment, system 100 may be configured to allow manufacturers or producer of pelleted fuels to access consulting services using system 100. User can utilize a system 120 to provide a listing of available ingredients and desired criteria and/or characteristics of the pelleted fuel to system 110 using user interface 1 12. System 1 14 can generate one or more recommended pellet fuel formulations using engine 114. The formulation may include the provided ingredients as well as recommendation and/or offers to sell additional ingredients to assist the user in maximizing their provided criteria. Further details regarding the operation of system 1 10 are provided hereinbelow with references to FIGS. 2 and 3.

[00024] Referring now to FIG. 2, fuel pellet formulation engine 1 14 is shown in further detail, according to an exemplary embodiment. Fuel pellet formulation engine 1 14 includes a formulation processing means 205, an ingredients database 210, an evaluation criteria database 215. Although engine 114 is shown as including particular systems, it should be understood that engine 1 14 may include more, fewer, and/or different systems configured to implement the functionality described herein.

[00025] Formulation processing means 205 may be configured to include a linear program that can take input data (e.g. ingredient availability information, evaluation criteria, ingredient profile, etc.) as a basis to compute a fuel pellet formulation. The fuel pellet formulation can include data specifying a combination of ingredients based on one or more evaluation criteria. Operation of processing means 205 is described in further detail below with reference to FIG. 3.

[00026] Ingredient database 210 may be any kind of information related to ingredients to be used in generating the fuel pellet formulation, such as BTU output information, cost information, user information, etc. The information stored in database 440 may include any of a variety of types of information such as generic information, information specifically related to the user, real-time information, historic information, geographically based information, etc. Ingredient information database 210 may be utilized by formulation engine 114 to supply information necessary for generating an fuel pellet formulation in conjunction with information supplied by the user.

[00027] Ingredient information database 210 may further be configured to access external databases to acquire additional relevant information, such as ingredient market information. Ingredient market information may similarly include current prices for ingredient, historical prices for output, ingredient producer information, ash content of ingredient information, market timing information, geographic market information, delivery cost information, etc. Ingredient information database 210 may further be associated with a Monte Carlo type simulator configured to provide historical distributions of ingredient pricing and other information that can be used as inputs to other components of system 100.

[00028] Ingredient engine 210 may further include a ingredient variability engine configured to provide tracking and projection functions for factors that may affect the fuel pellet performance of an ingredient. For example, the ingredient variability engine may be configured to project the BTU output for ingredients as a function of energy component content over time. Energy components include but are not limited to moisture, ash, protein, fat, fiber (such as NDF, ADF, and their constituents), starch, and the like. The energy component content for some ingredients may change over time based on method of storage, method of transportation, natural leaching, processing methods, etc. Further, the ingredient variability engine may be configured to track variability in energy component content for the ingredients received from specific ingredient producers to project a probable energy component content for the ingredients received from those specific ingredient producers.

[00029] The ingredient variability engine may be further configured to account for variability in other variables associated with the ingredients. The estimation of variability of an ingredient may be calculated based on information related to the particular ingredient, the supplier of the ingredient, testing of samples of ingredient, etc. According to exemplary

embodiment, recorded and/or estimated variability and covariance may be used to create distributions that are sampled in a Monte Carlo approach. In this approach, the characteristics of ingredients in an fuel pellet formulation are sampled repeatedly from these distributions, producing a distribution of characteristics. Formulations may then be revised for any ingredient for which the characteristics are projected to change. The process may be repeated until the desired confidence is achieved for all fuel pellet formulations.

[00030] Evaluation criteria database 215 may be any kind of information related to desirable or undesirable criteria to be maximized and/or minimized in generating the fuel pellet formulation, such as BTU output information, cost information, user information, etc. Evaluation criteria database 215 may be populated with both user supplied and system supplied evaluation criteria. An exemplary listing of evaluation criteria and their usage is provided below with reference to FIG. 3.

[00031 ] Referring now to FIG. 3, a flowchart 300 illustrating a method for generating a fuel pellet formulation is shown, according to an exemplary embodiment. In a step 310, ingredient information can be received. The ingredient information can be information related to ingredients to be used in formulation of the fuel pellet. The ingredient information can include a listing of ingredients available for use in production of a fuel pellet. The ingredient listing can be a listing of all available ingredients on a national market, a listing of ingredients available in a local market, a listing of ingredients available at a particular site, or any other set or subset of ingredients.

[00032] The ingredient information can further include additional information related to the available ingredients. The additional information can include the cost of the ingredient, the ingredient profile of the ingredient, any limitations of the availability of the ingredient and any other related information. The cost of the ingredient can be normalized to account for any shipping, storage, or other overhead costs. The ingredient profile can be a complete listing of all attributes known regarding an ingredient or a subset of the known attributes sufficient to make an analysis. The ingredient profile of the ingredient can further include moisture content, PDl value, lignin content, sodium content, chloride content, potassium content, sulfur content, and the like. The ingredient listing may vary according to the type of fuel pellet to include only ingredients that are available to produce certain types of fuel pellets, available in a given region of a country, etc.

[00033] Other properties, such as sulfur and moisture content often have effects on pellet fuel performance. High sulfur contents can lead to pollution causing combustion products. Also, high moisture content in a fuel may reduce efficiency. Table I (published by the Agricultural Utilization Research Institute Fuels Initiative) shows the reported values for properties of a conventional hardwood pellet as well as those for a variety of agricultural biomass fuels. Other biomass fuels may be suitable for use in formulating fuel pellets as well.

[00034] For example, literature reports that normal dent corn, as it is a seed in contrast to a stalk, contains more than 9% protein. Protein is made up of amino acids, which in turn have high levels of nitrogen. Further, agricultural materials, like corn, have significantly more sulfur, chlorine, phosphorus, and potassium than wood. It is also speculated that the higher moisture levels of biomass pellets compared to typical wood pellets could also contribute to corrosion problems due to the increased potential of condensed water (with acidic pH and corrosive salts) being in prolonged and direct contact with metal surfaces. Another consideration is the ash fusion temperature, ash fusion is the temperature where ash melts. If temperatures exceed the ash fusion temperature, this can cause evaporation and condensation of corrosive compounds within the stove and stove pipe. Alkali metals such as potassium and sodium can have a great impact on the ash fusion temperature. Chlorine can act as a catalyst in association with potassium and/or sodium. Sulfur may also react with alkali metals to form alkali sulfates, which can stick to the stove surfaces.

[00035] The fuel pellet may be formed by pelleting a mixture comprising agricultural biomass which includes whole corn, corn cobs, corn stover, wheat, wheat middlings, wheat straw, soy beans, soy bean hulls, soy cotyledon fiber, alfalfa, dried distillers grain, oats, oat straw, sugar beet pulp, almond hulls, walnut meal, bagasse, glycerol, methane fermentation by product and/or sunflower hulls. Other suitable agricultural biomass materials which may be used to form the present fuel pellets include co-products from corn milling processes (e.g. corn gluten feed, white fiber), oat hulls, rice hulls, rapeseed meal, rapeseed fractions, empty palm fruit bundles, and the like.

Table I

[00036] In a step 320, an evaluation criteria is received. The evaluation criteria may be chosen from a criteria related to fuel pellet characteristics. The evaluation criteria can include a single criteria or multiple criteria. If multiple criteria are provided, the criteria can be given weights designating their relative importance in a calculation. As an example, a producer may want to generate a fuel pellet that is weighted 70% on a heat output rate criteria and 30% on a desired ash content criteria. Table II below lists an illustrative set of evaluation criteria, one or more of which may be used in the present methods.

Table II. Evaluation Criteria

Ash

Fines

Density

Sodium

Potassium

Bulk Density

Chlorine

Sulfur

Moisture

BTU/lb

Nitrogen

[00037] Biomass fuel pellets for use in stoves and boilers should desirably conform to a variety of fuel pellet criteria. The pellets should have a sufficient heating value when burned to

be an efficient source of energy. The pellets should also have a low ash content to prevent equipment fouling. To avoid unsafe burning conditions, the pellets should also have a sufficient integrity such that the amount of fine particles is kept low.

[00038] To be economical, a fuel pellet should have a heating value of at least about

7000 BTU/lb (dry matter basis) when burned. Conventional hardwood may have a heating value of about 7900 BTU/lb.

[00039] Another requirement for a heating fuel is a low ash content. Ash produced by burning fuel may result in fouling of equipment. In certain embodiments, the adequate ash content may be up to about 15 wt.%, more desirably no more than about 10 wt.%. In some embodiments, an adequate ash content may be no more than about 3 wt.%. In other applications, it may be desirable to provide a biomass fuel pellet with an ash content of no more that about 2.5 wt.%. In yet other embodiments, the ash content may be no more than about 2.0 wt.% or no more than about 1.7 wt.%. In another embodiment the ash content may be no more than 1.0 wt.%.

[00040] Biomass fuel pellets must also have a sufficiently high integrity to limit the presence of fine combustible particles. A pellet's integrity can be measured by its pellet durability index ("PDI") as measured via a procedure similar to that described in Feed Manufacturing Technology III (American Feed Industry Association, Arlington VA. McEllhiney, R. R. (technical Editor). 1985. Appendix G Wafers, Pellets, and Crumbles - Definitions and methods for determining specific weight, durability, and moisture content; Section 6 Durability; Paragraph 2, Pellets and crumbles) the disclosure of which is herein incorporated by reference. The procedure includes the following steps:

1 ) Obtain a composite product sample by obtaining several samples at regular intervals throughout production. The samples should be mixed together for testing.

2) Screen sample with the appropriate screen as set forth on the Screen Sizes for Pellet and Crumbles Durability Tests (Table 1), by shaking it 30 times.

3) Place a 500-gram sample (+/- 10 grams) in a tumbler compartment. An exemplary tumbler may be 25 x 12.5 x 12, including four chambers and tumble at about 54 rpm.

4) Tumble sample for 10 minutes.

5) Screen sample with the appropriate screen as set forth on the Screen Sizes for Pellet and Crumbles Durability Tests by shaking it approximately 30 times.

6) Document the amount of sample and the amount of screened product.

[00041] Biomass fuel pellets desirably have a PDI of at least about 90, more desirably, at least about 95 and, most desirably, have a PDI of 98 or higher. The biomass fuel pellets may be generally cylindrical in shape and have a diameter of about 1/8 inch to 3/8 inch. More desirably, the fuel pellets may have a diameter of about 3/16 inch to 5/16 inch. The fuel pellets may suitably have an aspect ration (i.e. diameter : length) of about 1 :1 to 5:1.

[00042] Following the collection of data in step 310 and step 320, a processing step 330 can be performed. The processing step can be performed by a processing means. An exemplary processing means can be a computer as described with reference to FIGURE 2. The processing step can use a linear program to generate a fuel pellet formulation in view of the evaluation criteria provided in step 320. A linear program can be a mathematical model capable of solving problems involving a large number of variables limited by constraints using linear math functions. A variety of different linear math programs capable of solving problems of this type are known to those of skill in the art. One example of a program of this type is commercially available from Format International of St. Louis, MO as part of a computer software system for solving complicated multivariate problems.

[00043] The linear program can further include functionality to account for different weights associated with multiple evaluation criteria. The incorporation of weighting information in a linear program is known to those of skill in the art.

[00044] Generating a fuel pellet formulation may include providing a listing of ingredients and their relative amounts to be used in generating fuel pellets. Generating a fuel pellet may further include a listing of processing steps to be used by a manufacturer in generating fuel pellets using the fuel pellet formulation. The fuel pellet formulation may be transmitted to a user of a computing system 120, provided as an input to a manufacturing system configured to produce the fuel pellets, and the like.

[00045] Referring now to Table III, exemplary fuel pellet formulations based on a least cost formulation with maximum specifications on moisture and ash and minimum specifications set for BTU/lb and selected ingredients are shown.

Table III. Illustrative Pellet Fuel formulations

[00046] Referring now to Table IV and Figures 4-7, fuel pellet content profiles and proximate analysis exemplary showing actual laboratory analysis compared to formulated predicted values according to a number of exemplary embodiments

Table IV

Formulated value uses an analyzed BTU/lb for each of the ingredients ¹ BTU/lb nutrient. 2Formulated value uses a predicted BTU/lb for each of the ingredients' BTU/lb nutrient.

[00047] Table V shows a number of characteristics of common agricultural biomass materials illustrating proximate analysis and predicted values BTU/lb values.

Table V

[00048] Table VI shows the content of key minerals that can partially influence the ash fusion temperature associated with various agricultural biomass materials This information

may be used to develop an ash fusion prediction model and/or an ash fusion parameter for use in formulating the present fuel pellet formulations.

Table VI

[00049] It should be noted that although flow charts may be provided herein to show a specific order of method steps, it is understood that the order of these steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. It is understood that all such variations are within the scope of the invention. Likewise, software and web implementations of the present invention could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various database searching steps, correlation steps, comparison steps, and decision steps. It should also

be noted that the word "component" as used herein and in the claims is intended to encompass implementations using one or more lines of software code, and/or hardware implementations, and/or equipment for receiving manual inputs. It is to be understood that any method steps as recited herein (e.g., in the claims) may be performed by a configuration utility (e.g., Java™- based) executed by a computing device based on input by a user. Of course, according to various alternative embodiments, any suitable configuration utility, application, system, computing device, etc. may be used to execute, implement and/or perform method steps as recited in this disclosure (including the claims).

[00050] Although functions have been described herein as being performed by particular systems or sub-systems, it should be understood that any described function may alternatively be performed by any of system or sub-system of system 100. Further, functions described herein as being performed by system 100 may alternatively be performed by any external system coupled to system 100.

[00051] The invention is described above with reference to drawings. These drawings illustrate certain details of specific embodiments that implement the systems and methods and programs of the present invention. However, describing the invention with drawings should not be construed as imposing on the invention any limitations associated with features shown in the drawings. The present invention contemplates methods, systems, and program products on any machine-readable media for accomplishing its operations. The embodiments of the present invention may be implemented using an existing computer processor, or by a special purpose computer processor incorporated for this or another purpose or by a hardwired system.

[00052] As noted above, embodiments within the scope of the present invention include program products comprising machine-readable media for carrying or having machine- executable instructions or data structures stored thereon. Such machine-readable media can be any available media which can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, PROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. When information is transferred or provided over a network or

another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a machine, the machine properly views the connection as a machine-readable medium. Thus, any such connection is properly termed a machine-readable medium. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machine to perform a certain function or group of functions.

[00053] Embodiments of the invention have been described in the general context of method steps which may be implemented in one embodiment by a program product including machine-executable instructions, such as program code, for example, in the form of program modules executed by machines in networked environments. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Machine-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represent examples of corresponding acts for implementing the functions described in such steps.

[00054] Embodiments of the present invention may be practiced in a networked environment using logical connections to one or more remote computers having processors. Logical connections may include a local area network (LAN) and a wide area network (WAN) that are presented here by way of example and not limitation. Such networking environments are commonplace in office-wide or enterprise-wide computer networks, intranets and the Internet and may use a wide variety of different communication protocols. Those skilled in the art will appreciate that such network computing environments will typically encompass many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Embodiments of the invention may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination of hardwired or wireless links) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[00055] An exemplary system for implementing the overall system or portions of the invention might include a general purpose computing device in the form of a computer, including a processing unit, a system memory, and a system bus that couples various system components, including the system memory to the processing unit. The system memory may include read only memory (ROM) and random access memory (RAM). The computer may also include a magnetic hard disk drive for reading from and writing to a magnetic hard disk, a magnetic disk drive for reading from or writing to a removable magnetic disk, and an optical disk drive for reading from or writing to a removable optical disk such as a CD-ROM or other optical media. The drives and their associated machine-readable media provide nonvolatile storage of machine-executable instructions, data structures, program modules, and other data for the computer.

[00056] The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.