WO2010059807A2

WO2010059807A2 - Method of using a gas turbine generator system in dehydration applications

Info

Publication number: WO2010059807A2
Application number: PCT/US2009/065119
Authority: WO
Inventors: Christianne Carin; Alvin W. Fedkenheuer
Original assignee: Earthrenew, Inc.
Priority date: 2008-11-21
Filing date: 2009-11-19
Publication date: 2010-05-27
Also published as: WO2010059807A3

Abstract

The present disclosure provides methods related to modifying an existing manufacturing facility that includes a dehydration unit, the method including replacing the existing dehydration unit with a gas turbine system including a gas turbine configured to produce exhaust gases and a dryer vessel, wherein the dryer vessel is adapted to receive the exhaust gases from the gas turbine through a connection adapted to substantially preclude introduction of air into the dryer vessel.

Description

METHOD QF USING A GAS TURBINE GENERATOR SYSTEM IN DEHYDRATION APPLICATIONS

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. 61/116,935, filed November 21, 2008.

Technical Field

The present disclosure relates to methods of using a gas turbine generator system in various manufacturing processes that include a dehydration component.

Background

Industrial processing facilities for food, paper, drug and other manufacturing that involve the use of and removal of large amounts of water have a continuing need for more efficient and more economical equipment and processes for removal of water from raw material streams and/or intermediate product streams. Rising fuel costs always bring more urgency to the need for more efficient and lower cost water removal and dehydration technologies.

The present disclosure is directed to methods, apparatus, and systems for meeting some or all of these needs.

Summary

The present disclosure relates generally to methods of using a gas turbine generator system in various manufacturing processes including a dehydration component such as food/feed processing, pharmaceuticals/chemicals manufacturing, biomass fuel manufacturing, drywall manufacturing, etc. According to one aspect of the disclosure, the disclosure is related to a method of replacing conventional apparatuses and equipment used in various dehydration applications with a gas turbine generator system to improve the efficiency and the economics of the overall manufacturing processes. Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure. A brief description of the drawings is as follows:

FIG. 1 is a diagrammatic view of an example manufacturing process utilizing a gas turbine generator system, the process having features that are examples of inventive aspects in accordance with the principles of the present disclosure;

FIG. 2 diagrammatically illustrates retrofitting an existing manufacturing facility utilizing a conventional dehydration system with the gas turbine generator system of FIG. 1 to improve the efficiency and the economics of the overall manufacturing facility;

FIG. 3 is a diagrammatic view illustrating an example conventional wood pellet manufacturing process; FIG. 3 A is a diagrammatic view of a conventional pellet mill used in production of wood pellets;

FIG. 4 is a diagrammatic view illustrating an example conventional drywall board manufacturing process;

FIG. 4A is a diagrammatic view showing the pre-dehydration steps of drywall board construction;

FIG. 5 is a diagrammatic view illustrating an example conventional pharmaceutical manufacturing process;

FIG. 6 is a diagrammatic view illustrating an example conventional potato chip production process; and FIG. 6A is a diagrammatic view illustrating an example conventional corn chip production process.

Detailed Description

Reference will now be made in detail to the exemplary aspects of the present invention that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Industrial processing facilities for manufacturing or producing various types of products including but not limited to foods, drugs, fuels, construction materials, and other products utilize the use of and removal of large amounts of water, either from raw material streams and/or intermediate product streams. Such facilities have a continuing need for more efficient and more economical equipment and processes for removal of water from raw or intermediate feedstock used in production. Depending upon the type of industrial processing, conventional manufacturing facilities have resorted to various types of dehydration apparatuses and equipment to obtain the moisture levels needed in the feedstock. A number of conventional dehydration systems used in the production of the above-mentioned products include natural gas burners, microwave energy dryers, radiant heat dryers, dielectric dryers, superheated steam dryers, etc.

There is a substantial unmet need for more economical removal of water from high water content process streams. Moreover, there is a substantial need for cost and energy efficient dehydration systems that can be retrofit into existing manufacturing facilities and systems. FIGS. 1-2 diagrammatically illustrate a gas turbine generator system that can be retrofit into various existing industrial applications that utilize a dehydration component. FIG. 1 illustrates the gas turbine generator system integrated into an existing manufacturing facility. FIG. 2 illustrates retrofitting an existing manufacturing facility utilizing a conventional dehydration system with the gas turbine generator system of FIG. 1 to improve the efficiency and the economics of the overall manufacturing facility.

The gas turbine generator system shown in FIGS. 1 and 2 is described in further detail in U.S. Patent Nos. 7,024,796 and 7,024,800, the entire disclosures of which are incorporated herein by reference. In the present disclosure, various aspects and details of the gas turbine system illustrated in FIGS. 1 and 2 will be described. Also, various conventional manufacturing processes wherein the gas turbine generator system of the present disclosure can be retrofit and utilized will be described. Although only a few different example manufacturing processes that are well suited for the gas turbine generator system of FIGS. 1 and 2 are discussed in the present application, it should be noted that the gas turbine generator system illustrated and described herein can be utilized in and retrofit into virtually any application including a dehydration component, wherein the feedstock input and output parameters and conditions are similar to those that can be obtained by the gas turbine generator system, as will be described in further detail hereinafter.

Referring to FIG. 1, the gas turbine generator system 10 of the present disclosure includes a gas turbine 101 and an electric generator 102. The gas turbine has air intake filter 104 and fuel feed 103. If desired, optional exhaust gas bypass 908 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 a dryer vessel 200. The exhaust gas bypass 908 around the dryer vessel can be directed to any appropriate downstream unit, such as a separator and/or condenser 208 of the gas turbine generator system. The gas turbine 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 high water content feedstock is not present in the dryer vessel 200. However, when both are present, any such air inlet is normally 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. An optional burner 107 can also be included to provide a 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 107 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 high water content feedstock is typically introduced into the system by mechanical means, such as pump, auger or whatever is appropriate for a particular industrial process or feedstock.

Depending upon the process, the output from the dryer vessel 200 may be transferred by conduit 205 to a separator 208 where solids and gases may be separated. The gases may pass to the atmosphere or to other processes, depending upon the industrial application. The output from dryer vessel 200 can also pass through optional heat exchangers for recovery of process heat for use downstream or in preheating the high water content feedstock or turbine intake air. The solids output from separator 208 may be directed downstream for further processing, depending upon the nature of the manufacturing process. As will be discussed in further detail below, according to one example, the solids output from the dryer vessel 200 may pass to a pelletizing unit to form solid pellets. An example pelletizing operation utilizing the gas turbine generator system of the present disclosure is described in detail in U.S. Patent Nos. 7,024,796 and 7,024,800, the entire disclosures of which have been incorporated herein by reference.

The gas turbine generator system of the present disclosure can be positioned on the operation site and integrated into the industrial facility. According to another embodiment, the gas turbine generator system can be provided as a portable, truck- mounted (e.g., semitrailer trucks) units that may be adaptable to a variety of sites that may have limitations on space available.

Still referring to FIG. 1, the existing manufacturing facility that is suitable for utilizing the gas turbine generator system may include an operation 901 involving a high water content feedstock. In addition to the dehydration of the high water content feedstock, the gas turbine generator 101/102 produces electric power 905, which can be either sold to the local power company 906 or distributed by 907 for use in the manufacturing operation or the processing units in the systems of this disclosure. The economics of each commercial operation, fuel costs, selling price/purchase price of electricity and capital cost of equipment will determine whether the electricity is used internally in the manufacturing operation, sold to the power company, used in the systems of this disclosure or used in other nearby operations or any combination thereof.

The exhaust gases from the gas turbine 101 are passed to the dryer vessel 200 by the connection 105. The connection 105 precludes outside air from entering the dryer. As disclosed herein, the system is operated so that the oxidation of the high water content feedstock in the dryer vessel 200 and elsewhere in the system is minimized and substantially avoided. The dryer vessel 200 may also serve as a silencer for the gas turbine to satisfy any noise restrictions that might be applicable, hi operation of the gas turbine generator system, the high water content feedstock 215 is fed to the dryer vessel 200 along with the exhaust gases from connection 105 and any auxiliary heat provided from alternate or auxiliary heat source 107. If bio-material, the feedstock to be dehydrated preferably comes directly from the high water content feedstock in 901 in manufacturing facility 900 so it is fresh and has little or no time for bioconversion. Other high water content feedstock sources 910 can be used or included in the system, such as stockpiled feedstock or feedstock from other operations that is brought in to be combined or mixed with the feedstock from the immediate facility. While the present disclosure is illustrated herein with an embodiment of a dryer vessel, it will be apparent to one skilled in the art other configurations and operating designs of this system can be used depending on needs and configurations of the manufacturing facility employing this system. For example, a paper, cardboard or drywall facility may have the need to remove water from a slurry, mat or laminate on a moving belt instead of inside a dryer vessel per se. In such an operation, the exhaust gases from the gas turbine can be directed through appropriate conduits for direct contact with the material

(feedstock herein) on the belt to accomplish the desired water removal, dehydration and/or conversion of material as disclosed herein. In essence, in such configuration the entire enclosure around the belt and the area where the turbine exhaust gases contact the material on the belt becomes the "dryer vessel" for purposes of description of this system.

As discussed above, the output from the dryer vessel 200 may be sent via 205 to the separators/condensers designed to separate the solids 912 for further processing downstream, to condense the water vapors as reclaimed water and to clean the gases 914 vented to the atmosphere. The reclaimed water can be used downstream as process water, recycled for use in the manufacturing facility, for preparing or conditioning the high water content feedstock, used for industrial process water or other uses. The solids output 912 from the separator units 208 may be further processed (e.g., as in milling, pelletizing, granulating, bagging, etc.). Also, the solids 912 can be used as an intermediate to form other types of products. For example, the dry material can be baled, formed into shapes, slurried for pumping, or can be used alone or in combination with other materials for incineration to utilize the fuel value of the material (e.g., wood pellet).

In each of the downstream operations, water vapor may be recovered and recycled to the separators/condensers 208 for reuse. As is apparent, the systems of this disclosure are adaptable to various configurations and various designs depending on the processing needs and economics of particular manufacturing operations. Various conventional heat recovery and recycle aspects, not shown in FIG. 1, can be designed into commercial installation of the systems of this disclosure by using ordinary process engineering design skills, including use of gas/vapor stream 914 for various heat recovery and pre-heating applications, insertion of binders, additives and blending materials at various desired points in the system, cooling the combustion air 904, e.g., by water spray, to increase efficiency and power output of the gas turbines, mechanically pretreating feedstock for dewatering very high water content feedstock, etc., as will be apparent to one skilled in the art following the disclosure herein.

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 feedstock processing capacity but also to provide operation flexibility for processing varying feedstock loads and for performing equipment maintenance without shutting down the operation.

The term "high water content feedstock" is used herein to mean and include industrial manufacturing process streams which can be raw material streams, intermediate streams or semi-finished product streams that need water removed to enable further processing or produce a final product and which may optionally comprise organic materials or which may optionally comprise inorganic materials or mixtures thereof. This disclosure describes efficient processes and systems for removal of water from process streams and/or provide heating to thermally convert or react a product stream to a converted or reacted product (in batch or continuous operations).

As will be discussed in further detail below, uses of the gas turbine generator system of this disclosure include, but are not limited to, removing water from, drying and treating continuous process streams and/or batches in paper manufacturing, manufacture of particle board, cardboard, drywall board, green board, etc., potato processing, human food production, such as production of oatmeal, corn flakes, corn syrup, corn meal, corn starch, mashed potatoes, sugar, milk, powdered milk, cheese, sauces, ketchup, jams and jellies, "instant" coffee, juice concentrates, and other dehydrated products which are rehydrated at the time of use, beer and other fermented and/or distilled products, snack foods and other consumer products, such as pet food, drugs, pharmaceuticals, cosmetics, chemicals, biomass fuels such as wood pellets, cordwood, wood chips, waste paper, other agricultural byproducts, and other manufacturing processes. As is apparent, the systems and processes of this disclosure can be used to process a feedstock by dehydration without conversion or reaction, by conversion or reaction without dehydration, or by any combination or proportion of both. The systems and apparatus of this disclosure can also be adapted for installation at particular individual facilities to intercept the process streams for water removal.

The present disclosure describes simplified, economically efficient processes to produce liquid, paste, slurry, or solid products that comprise the solids content of the high water content feedstocks (including intermediate process streams or intermediate products) that have been dehydrated to the desired moisture content level and/or have been converted, reacted or altered physically and/or chemically as desired. This disclosure also describes recovering and recycling the water removed from the feedstock, which water can be used for process water or other industrial uses, and for recovering and recycling all solids (fines or other) produced in the process, so that there are no significant solid products produced or resulting from this system other than the desired products suitable for commercial use. The selection and adaptation of the processes, apparatus and systems of this disclosure to treat or process a particular feedstock to produce a particular desired solid, liquid, paste or slurry product will be apparent to one skilled in the art from the disclosure herein. According to this disclosure, one preferable way of providing the hot gases for contact with the high water content feedstock is the exhaust from a gas turbine, and preferably a gas turbine electric generator. According to the system of this disclosure, the gas turbine may be fueled from locally available conventional fuel sources, such as pipeline natural gas. The electricity produced from the gas turbine generator is preferably used internally in the manufacturing facility or in other nearby operations as a source of power or in a combination of uses for power and heat recovery from the processes described herein, or can be sold into the local power grid as a revenue source.

A preferred feature of the process and apparatus of this disclosure is that the gas turbine and the high water content feedstock dryer vessel receiving the exhaust gas from the gas turbine are connected together such that induction of outside air into the dryer vessel is substantially or completely precluded and the dryer vessel preferably receives the exhaust gases directly from the gas turbine. It is preferred that almost 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. It is also recognized that excess exhaust gases from the turbine not needed for the dryer vessel operation can be diverted to provide heat required in other aspects of the manufacturing facility or in other nearby operations.

In certain embodiments of the system, it is preferred that the exhaust gases result from conventional and efficient combustion ratios in the gas turbine so that the exhaust gases contain a relatively small amount of free oxygen, essentially no unburned fuel, no exposed flame and that the optimum exhaust gas temperature (EGT) may be achieved, for maximum heat produced, per unit of fuel consumed. The absence of significant amounts of excess oxygen in the exhaust gases, precluding outside air induction into the dryer vessel, the absence of exposed flame and operation at the temperatures set forth herein prevents significant oxidation of the high water content feedstock in the dryer vessel, preserves the maximum nutrient value in the high water content feedstock (if bio materials) for containment in the end product and, when the output of the dryer vessel is a dry, oxidizable material, prevents the danger of fire damage to the equipment and provides an operation safe from flash fires in the dryer vessel. The absence of significant amounts 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 system before being released into the atmosphere. In other preferred operations of this system it may be desired or essential that air or oxygen be introduced in controlled quantities or ratios to provide a desired oxidation or chemical conversion of the high water content feedstock in the dryer vessel.

For use in this system, in certain embodiments, the high water content feedstock have a moisture content of at least 20% by weight water, or at least 30%, or at least 50%, or at least 70% in order for the economic benefit of this system to be best utilized. However, in some operations the water content of the feedstock material may be as high as 90%, 95% or even 98%. In addition, the feedstock material may be a solution with all solids dissolved therein, where the dissolved solids are precipitated out as the water is evaporated from the feedstock in the processes and systems of this disclosure. As discussed above, the present system can efficiently and economically process such high water content feedstocks to not only recover the solids content in the form of a final product, but to also recover the process water, which can be recycled and reused. This system can process and dehydrate high water content feedstocks efficiently and economically due to the fact that, in its preferred aspects, from a given combustion of natural gas fuel, the gas turbine generator provides both electric power for use or sale and heat for processing the feedstock, plus the excess steam produced in the dryer vessel can be used downstream, upstream or in other nearby operations, such as for preheating high water content feedstock, process heat, etc., providing additional operational fuel efficiency. This system can be adapted as disclosed herein, to contain and process not only the water and solids but also the gases produced in a manufacturing operation, hi some cases it may be desirable for economic operation reasons to mechanically separate part of the water from high water content feedstock, e.g., by centrifuges, filters or presses, before processing the feedstock in the system of this disclosure. Such separated water can be recycled for use as disclosed above.

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 degrees F, preferably at least about 700 degrees F, more preferably at least about 900 degrees F and most preferably greater than about 1,000 degrees F. Gas turbines are the heat source preferred for use in this system because of their efficient operation and high heat output. The gas turbine generator is further preferred for use in this system due to the production of energy by the generator, which energy can be utilized or sold to improve the economics of the operation of this system. 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 system. This can be an option when it is economically more important to have small (e.g., trackable) 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 system can be fueled from any available source with any suitable fuel for the particular gas turbine and for the process equipment designed. The preferred and conventional fuels are sweet natural gas, diesel, kerosene and jet fuel because the gas turbines are designed to run most efficiently on good quality fuels of these types and because of their common availability, particularly at remote agricultural operations, where the units of this system may be located. However, other fuels that can be used to fuel the gas turbine include 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 system 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 and 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 solids 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 an 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. For large industrial installations, where there is no interest in moving the system between facilities, the gas turbine generator can be any large size suitable for permanent installation at the facility, such as a 10 MW, 20 MW or 40 MW unit, or larger. The dryer vessel employed in this system can be any type or configuration that is suitable for drying the high water content feedstock available and that can be adapted for receiving the gas turbine exhaust gases and receiving the high water content feedstock without allowing a significant amount of outside air to enter the drying chamber in the dryer vessel where the exhaust gases contact the high water content feedstock. The objective of the design of the gas turbine exhaust connection to the dryer vessel for purposes of this system is to preclude any significant outside air from entering the dryer vessel to help prevent significant oxidation of the high water content feedstock. As previously pointed out, this is preferred to preserve the organic matter, carbonaceous and/or nutrient values present in those types of high water content feedstocks, to prevent fires and to provide a safe operation. The turbine may 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. Other operational parameters are certainly possible. As discussed above, additional sources of hot gases can optionally be connected to the dryer vessel according to this system 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 or surge load conditions or for backup in the event the gas turbine goes offline.

It will be recognized that in some operations of this system, not all outside air can be excluded and oxidation of the high water content feedstock cannot be completely precluded, primarily because of the air present in and entrained in the high water content feedstock, the air dissolved in the moisture present in the high water content feedstock and excess oxygen that may be present in the turbine exhaust gases. Li addition, in some cases oxygen may be produced or liberated from the organic or other materials present in the high water content feedstock when the thermal treatment and conversion takes place and decomposes or converts such materials. Therefore, the terms as used herein which refer to "preclude introduction of air," "without significant oxidation," and the like, are used in the above operational context and with the recognition and intended meaning that the air or oxygen entering the system as part of the high water content feedstock or exhaust gases or produced in the thermal conversion process is not intended to be precluded and that the oxidation that may occur as a result of that air entering the system with the high water content feedstock is not intended to be prevented. However, such a level of oxidation is not considered significant within the scope, context, or the meanings of those terms as used herein. Similarly, "without significant pyrolysis" is used herein to mean that not more than an insignificant portion of the high water content feedstock is pyrolized. Pyrolysis products are normally undesirable in the processes and products of the present disclosure, and the processes and equipment of this disclosure are operated to achieve the desired drying of the high water content feedstock and the desired conversion of various high water content feedstock components to the desired final products. Following the disclosures herein, it will be apparent to one skilled in the art for some applications, to control the exhaust gas temperatures, the contact times and/or residence times in the dryer vessel, the moisture content of the solids and of the vapor phase in the dryer vessel and other variables in order to process a particular high water content feedstock to achieve the desired results and to maximize the desired final products, hi other applications, the temperatures, contact times and other operating parameters can be adapted to achieve a desired level or degree of oxidation or pyrolysis, if the properties of the final product to be made using the systems of this disclosure require oxidation or pyrolysis of the feedstock. Exclusion of outside air is also preferred for economic efficiency as well, because heating excess or outside air along with heating the high water content feedstock reduces the efficiency of the process. In some instances where the high water content feedstock is very low in moisture content or too dry for preferred operation of this system, water can be added to the feedstock, to the turbine exhaust, to the turbine intake or to the dryer vessel to raise the moisture level in the dryer vessel to a level for efficient operation and to produce a solids material from the dryer vessel with a desired moisture content.

It will be recognized that the operation of the dryer vessel is normally to dry or reduce the moisture content of the high water content feedstock, but it is to also achieve the high temperature heating of the high water content feedstock to convert certain components and to achieve a chemical or thermal alteration in the feedstock to provide the content and properties desired in the final product (e.g., in production of wood pellets). As noted, one aspect of this disclosure is the thermal conversion of the various components of the high water content feedstock without significant oxidation from the outside air. Although the range of components in high water content feedstocks are widely varied, it will be understood by one skilled in the art of conventional processing of a particular high water content feedstock how to effectively and efficiently employ this system to improve the economics of the manufacturing operation processing that feedstock. The types of dryer vessels that can be used in this system are, for example, the following: Rotary drum with or without internal scrapers, agitation plates and/or paddles; Stationary "porcupine" drum dryer with or without scrapers and/or agitator plates and/or paddles; 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; Evaporator systems; Baking ovens. Examples of commercially available dryer vessels useful in or that can be adapted for use in this system include: Scott AST Dryer.TM. 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, Inc. direct or indirect dryer systems; Pulse Drying Systems, Inc.; MEC Company dryer systems. Further examples of dryer vessels useful in or that can be adapted for use in this system are disclosed in U.S. Pat. Nos. 5,746,006, 5,570,517, and 6,367,163, 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 high water content feedstock in the system of this disclosure. The dryer vessel also functions as the thermal treatment/conversion/alteration vessel or oven in which the high water content feedstock is heated to sufficient temperatures for sufficient times to produce the desired final materials and products as disclosed herein. In addition, the dryer vessel need not provide direct contact of the turbine exhaust gases or other heat source and the high water content feedstock, but can provide indirect heating of the high water content feedstock to achieve the drying and/or thermal treatment/conversion/alteration desired. The dryer vessel can be lined with appropriate material to prevent or reduce corrosion, erosion or excessive wear. It will be recognized that the systems of this disclosure can be adapted to perform various functions in various configurations in a particular installation or operation. For example, two dryer vessels can be operated in series where a high water content feedstock is dried in the first dryer vessel then the output from the first dryer vessel is thermally treated in the second dryer vessel to achieve the desired chemical or physical conversion or alteration. In such an arrangement, the exhaust gases can be supplied from a single gas turbine exhaust split between the two dryer vessels, or can be supplied by two separate gas turbines. From this example it can be seen that the processes, apparatus and systems of this disclosure can be adapted to operate various equipment components in series or in parallel to perform various processing functions desired following the teachings of this disclosure to achieve the effective and economic operation thereof.

Another aspect of the dryer vessel adapted for use in this system is that the dryer vessel preferably also functions as the silencer 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 system, due to the connection between the gas turbine exhaust and the dryer vessel preferably 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 high water content feedstock, 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 may be 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 may be desirable to accommodate startup, shutdown, upset or feedstock variability, but will normally be operated as a closed system having only final product output and clean gas venting. The turbine exhaust can optionally be partially or temporarily wholly diverted to other downstream units, bypassing the dryer vessel, when needed for supplemental heat in other process units or for startup, shut-down or upset. Another aspect of this system 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 system as described above. To achieve high efficiency of operation of this system, 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 high water content feedstock 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 system 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 system will be apparent to one skilled in the art following the teachings herein.

Another advantage provided by this system results from the contact of the gas turbine exhaust gas with the high water content feedstock in the confined space of the dryer vessel without significant outside air present. The NOx and SOx emissions, and to some extent CO and CO2 emissions, in the gas turbine exhaust are substantially reduced, and in some cases reduced to zero, by absorbing or complexing of the NOx and SOx components into the high water content feedstock, where they remain absorbed, complexed or fixed in the dried or treated material exiting the dryer vessel and in the product after processing into other forms. This provides the advantage of both lowering or eliminating the emissions of NOx and SOx (and CO/CO2) into the atmosphere and adding the nitrogen, sulfur and carbon components to the nutrient value of the product (if desired) produced by the process and apparatus of this system.

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. The typical turbine exhaust gas temperature entering the dryer vessel will be in the range of about 500 degrees F to about 1,500 degrees F, depending on moisture and other content of the high water content feedstock and the desired condition of the product output from the dryer vessel, hi smaller systems with smaller engines, the inlet exhaust gas temperature can be as low as about 300 degrees F or about 350 degrees F. A preferred range is from about 600 degrees F to about 1200 degree F, and it is more preferred that the inlet temperature be at least about 650 degrees F and most preferably at least about 700 degrees 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 high water content feedstock. 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 water content feedstock is contacted with high temperature gases. Such contact causes the formation, sometimes instantly, of superheated steam as the moisture comes out of the high water content feedstock, then that superheated steam heats and drives the moisture out of adjacent high water content feedstock. It is believed that this mechanism is responsible for quick drying of the high water content feedstock to a low moisture content so that the remaining residence time of the high water content feedstock in the dryer vessel contributes to the desired thermal treatment/conversion/alteration or "cooking" thereof. Some high water content feedstocks may require lower temperatures but longer residence time to achieve the conversion or "cooking" needed to produce a product having self- binding (e.g., in wood pellet manufacturing) or other desired properties. The temperature of the material exiting the dryer vessel will typically be in the range of about 150 degrees F to about 450 degrees F and preferably between about 200 degrees F and about 350 degrees F. In some operations, the dryer vessel exit temperature of the material should be at least about 175 degrees F and preferably at least about 200 degrees F. As used herein the term "converted material" is used to refer to and means the dried high water content feedstock which is produced in the dryer vessel by reducing the moisture content of the high water content feedstock from an existing level to a lower level according to this disclosure and/or achieving the chemical alterations and conversions referred to herein. The "converted material" may be considered an intermediate product that is suitable for further processing into a final product suitable for consumer, commercial or industrial use. Depending upon the manufacturing process, the converted material from the dryer vessel may be further processed, for example, by milling, granulating, pelletizing, prilling, or to form flakes or other forms of the final product suitable for conventional handling, packaging and/or transport. The converted material can also be milled or otherwise powdered and made into a slurry or other liquid or pumpable product that can be recycled or used as needed. The industrial demands and the local economics will have an impact on determining the end use to be made of the material produced from the dryer vessel or the final product produced from the system of this disclosure and whether the material from the dryer vessel is subjected to further processing.

As discussed above, the high water content feedstock may typically have a moisture content between about 50% and about 90% by weight, or between about 60% and about 80% by weight or between about 65% and about 75% by weight. (Percent by weight, as used herein, is in reference to percent of the component in question based on the total weight of the mixture referred to.) Although high water content feedstock of lower moisture content, for example, as low as about 40% by weight or even 20% by weight can be processed in this system. Certain high water content feedstock treated/dried as disclosed herein has a moisture content of at least about 50% by weight, or at least about 60%, or at least about 70% by weight. When the high water content feedstock has a high moisture content in this range, processing advantages are achieved from the essentially instant production of steam and superheated steam at the inlet of the dryer vessel where the 1,000 degree F exhaust gases contact the high moisture high water content feedstock at atmospheric or subatmospheric pressure. The steam and superheated steam thus produced may contribute to the drying, cooking and conversion of adjacent or nearby and downstream particles of high water content feedstock, which enhances the efficiency of the dehydration process.

It may be preferred for operation of the process and apparatus of this disclosure for certain industries that the high water content feedstock be mixed and blended among batches or different parts (top, bottom, indoor, outdoor, etc.) of the same batches to provide a uniformity of high water content feedstock properties (e.g., in producing wood pellets). This preparation may enable the production of a more uniform material from the dryer vessel, and simplify control of the process operations.

The temperature of the high water content feedstock will typically be ambient, i.e., in the range of about 30 degrees F to about 100 degrees F, but can be lower than 30 degrees F, provided that any frozen agglomerations do not interfere with the feedstock preparation or the operation of the dryer vessel and feedstock feeder equipment. The high water content feedstock may be used at any temperature direct from a manufacturing facility or from a process unit, which may be at an elevated temperature. The economics of the systems of this disclosure may be improved if the high water content feedstock is at an elevated temperature or is preheated prior to introduction into the dryer vessel. If such feedstock preheating is employed, it may be done in any desired fashion, such as heat exchanger, solar heating, heated conveyers or augers or heated concrete slabs in the staging and feedstock preparation area, and may be done with heat recovered and recycled from the process systems of this disclosure.

The contact time between the turbine exhaust gases and the high water content feedstock will be determined by several variables including moisture content of the feedstock, moisture content desired in the dryer vessel output material, the chemical alteration/conversion desired, volume and temperature of the exhaust gases entering the dryer vessel and other factors. The contact time will be regulated to provide not only the drying desired, but also to elevate the particles of high water content feedstock solids to sufficiently high temperatures to sufficiently convert components present in the feedstock when such conversion is desired, and/or to produce a self-binding product (e.g., wood pellets), when desired. The actual temperature attained by the particles may not be important to determine, so long as the desired levels of said component destruction and conversion, the desired level of self-binding or other desired properties are achieved. The desired contact time can be varied and regulated by the dryer vessel volume and size and by the throughput volumes of the feedstock and exhaust gases. The heat transfer from the exhaust gases to the feedstock, and consequently the temperature to which the feedstock is heated, will mainly be a function of the mass ratio of exhaust gas to feedstock. The exhaust gas flow and the high water content feedstock flow through the dryer vessel may be concurrent, countercurrent, single stage, multiple stage, etc., depending on results desired and various system designs and economic considerations.

The output from the dryer vessel comprises steam, water vapor, gas turbine combustion gases and solids that are dried and/or thermally treated and converted to desired forms. Typical dryer vessel outlet temperatures of the gases and/or solids will normally range from about 200 degrees F to about 350 degrees F, but lower or higher temperatures may be selected and/or desired for economic, product quality and/or process efficiency reasons. The outlet temperatures can be from at least about 110 degrees F to at least about 500 degrees F, preferably at least about 180 degrees F and more preferably at least about 200 degrees F. It is generally desired that the solids material exiting the dryer vessel will generally have a moisture content between about 10% and about 15% by weight, but can range from about 5% to about 25% by weight. Again, depending upon the industrial requirements, lower or higher moisture content of the dryer vessel output solids may be selected and/or desired. The steam, water vapor and combustion gases exiting the dryer vessel may be routed through heat exchangers (for recovery of process heat usable downstream operations or upstream in feedstock or turbine intake air preheating), condensers (for recovery of process water for upstream or downstream use), and other conventional process equipment.

The solids output from the dryer vessel, referred to herein as converted material, maybe further processed (e.g., by milling, granulating, pelletizing, prilling, flaking or other processing) to produce a final feed, fuel, recycle or other product in the form desired for packaging or bulk distribution, transport and use. Such operations and equipment useful in this system are those that are conventional and well-known, since the output from the dryer vessel comprises solid and vapor components that lend themselves to such processing. Whatever the product in whatever form, the process, system and equipment of this disclosure provide for environmentally and economically effective processing of high water content feedstocks to remove them as environmental liabilities and provide products which are commercially useful, and to eliminate disposal in a municipal sewer or landfill. This system can be used to produce a variety of products and materials from high water content feedstocks, but the preferred materials and products are those that have no significant undesirable components remaining that have not been converted or destroyed in the heating, chemically altering and/or drying treatment in the dryer vessel or other operations.

The products and materials produced by this system may be useful for and include blends with other materials, products or chemicals, as may be desired for particular end uses requiring particular properties or characteristics. Such other materials and additives can be added and blended at any appropriate point in the process: blended with the high water content feedstock, added to the dryer vessel, added in the process water at any point, added to the material exiting the dryer vessel, added as part of any downstream operation such as milling, granulating, pelletizing, flaking or other processing or simply mixed with the final product or blended in before bagging or packaging or at the point of use. For example the final products, while usually relatively odor free, can be blended with other materials that can either provide a pleasant odor or provide flavoring as desired as well known in the food processing industry. The systems of this disclosure can be particularly useful in essentially eliminating the release of harmful environmental emissions from manufacturing operations by directing manufacturing operations exhaust into the combustion air of the gas turbine. By routing the manufacturing operations exhaust through the gas turbine, emission gases are burned along with the regular gas turbine fuel supply, thereby converting CH4 to H2O and CO2 and converting the mercaptans and other noxious or acrid compounds to H2O, COx, NOx and SOx. Second, when an optional dryer vessel is connected to the gas turbine exhaust, the exhaust gases from the gas turbine are contacted with a high water content feedstock, where the NOx and SOx and to some extent COx gases are absorbed into or complexed with the high water content feedstock as it is dried and/or thermally treated to form a converted material or to form a final product. When desired aspects of this system are employed utilizing the water removal and dehydration processes, the contacting of the gas turbine exhaust gases with the high water content feedstock absorbs or

"scrubs" at least a portion of NOx, SOx, and COx and other compounds resulting from conversion of emissions in the gas turbine combustion from the exhaust gases and retain those compounds in the water removed or in the resulting stream containing the solids of the feedstock, thereby preventing those resulting compounds from being released into the atmosphere. FIG. 2 diagrammatically illustrates the gas turbine generator system of FIG.

1 described in detail above being retrofit into a conventional manufacturing process and replacing a conventional dehydration component of that manufacturing process. FIG. 3 illustrates one example of a manufacturing process that is suitable for utilization of the gas turbine generator system of FIG. 1. The process shown in FIG. 3 relates generally to the manufacturing of biomass fuels, specifically to the manufacturing of pelletized bio fuels. Pelletizing may be used as a process to make waste materials into solid fuel. Wood pellet is one of the most commonly used pelletizing materials. The most common residential pellets are made from sawdust and ground wood chips, which may be waste materials from trees used to make furniture, lumber, and other products. Wood pellets can be made from any type of Agro-Forestry waste: Groundnut-shell, Sugarcane Biogases, Caster Shells/Stalk, Saw dust, Coffee Husk, Paddy Straw, Sunflower Stalk, Cotton Stalks, Tobacco waste, Mustard Stalk, Jute waste, Bamboo Dust, Tea waste, Wheat Straw, Palm husk, Soybeans husk, Coir Pitch Barks/Straws, Rice husks, Forestry wastes, Wood chips and many other Agro wastes.

Pellet fuels provide a low net CO2 solution because the quantity of CO2 emitted during combustion is equal to the CO2 absorbed by the tree during its growth. During burning, emissions such as NOx and volatile organic compounds are very low, making pellet fuel one of the most non-polluting heating options available.

The wood pellets normally have a cylindrical form 6mm to 8mm (1/4 to 5/16 inch) in diameter and are normally no longer than 38mm (1.5 inches). The heating value of the pellets varies with the composition of the wood, including the wood species, resins and bark. Pellets made from the wood of non-resinous species have a higher heating value of 18.6 to 19.8 MJ/kg (8000 to 8500 Btu/lb.) and fuels from the bark yields values of 17.2 to 22.8 MJ/kg (7400 to 9800 Btu/lb.). The wood of resinous species yields 20.0 to 22.5 MJ/kg (8600 to 9700 Btu/lb.) and the bark has 20.4 to 25.1 MJ/kg (8600 to 9700 Btu/lb.). Pelletizing itself does not change the calorific value of the material. Pelletizing merely puts the material in a different physical form with higher density, better storage, handling, and transportation characteristics. However, the dehydration process that occurs prior to the pelletizing step improves the calorific value.

Wood is basically made of three components: 1) Cellulose - the fiber that constitutes 40 to 50% of the wood composition; 2) Hemicelluloses, which constitutes 20 to 35%; and 3) Lignins, which constitute 15 to 35%. The lignins occurring naturally in the sawdust hold wood pellets together, so they usually contain no additives.

Pellets are produced by compressing the wood material feedstock which has first been passed through a hammer mill to provide a uniform dough-like mass. This mass is fed to a press where it is squeezed through a die having holes the size required (normally 6mm diameter, sometimes 8mm or larger). The high pressure of the press causes the temperature of the wood to increase greatly, and the lignin plassifies forming a natural "glue" that holds the pellet together as it cools. Pellets commonly manufactured and used have less than 10% water content, are uniform in density, have good structural strength, and low dust and ash content. Because the wood fibers are broken down by the hammer mill, there is virtually no difference in the finished pellets between different types of wood. Thus, the pellets can be made from nearly any wood variety. The pellet production process, as described herein, is ideal for utilizing the gas turbine generator system of the present disclosure. In pellet production, the densification of the pellet itself is only a part of an overall system necessary to achieve the finished product. Pre-processing steps such as grinding and drying must occur prior to pelletizing and densification. The actual pelletizing process occurs after the wood waste has been through all the preparation steps required to bring the wood waste to a consistent composition and moisture. As discussed above, the pellets are produced with no added adhesives, thus the process requires no additives, but rather uses the natural adhesives present in the wood to bind the pellets together. The self bonding of wood to form a pellet involves the thermo-plastic flow of the polymeric material, basically the lignin and hemicellulose naturally occurring in the wood feedstock. These materials become plastic and flow at specific conditions of temperature and moisture.

In production, because the wood used is often from waste materials, the wood wastes frequently contain materials such as metal, stones, glass, etc. These types of materials must be removed prior to further processing steps. The wood material (if the thickness thereof is greater than 10mm) is then chipped into small pieces, which are then crushed into wood powder having diameter of less than 3mm.

The wood being used should be as consistent as possible. This can be controlled in a number of ways, either with initial control and/or blending the as- received feedstock in some manner. If there is a wide range in the wood being received, many producers use a process of storing the different types of woods in separate bins and metering the appropriate percentage of each wood to a blending process prior to either the drying or the final grind process. In the drying portion of the process, the wood powder must be brought to a feedstock moisture level of about 10% to 1%. This initial moisture level of the waste wood is vital to set the system requirements for downstream processes. There are three conditions of wood that determine the level of drying necessary: 1) Greenwood (non-dried wood waste); 2) Pre-dried feedstock; and 3) Feedstock that is too dry. Greenwood will normally require a significant amount of drying. Conventionally performed in burners, the drying component of the process can utilize the gas turbine exhaust generator of the present disclosure. Pre-dried feedstock normally includes waste products such as planar shavings and are usually received in the correct moisture range by the very nature of the way they are formed. This type of feedstock generally goes directly to a hammermill for final grind, prior to pelletizing. Feedstock that is too dry needs to have water added to the final grinding in order to effectively wet the wood and allow the lignin to absorb water before the wood reaches the pellet machine. Lignins tend to be hydrophobic. Thus, once water is removed, it is very difficult to get it back into the feedstock and time is needed for this to occur effectively.

After the wood waste has been mixed and dried properly, a pellet mill then forms the pellet. FIG. 3 A diagrammatically illustrates a pellet mill. As shown, the roller assembly is a cylinder idling on bearings. The only driving force acting on the roller assembly is the frictional turning force from the die, acting through a very thin layer of feedstock between the die and the roll. The die is the rotating, driven component, composed of a ring of steel perforated with holes through which material flows at pellet density. Work Area can be defined as the area where the converted material feedstock is received at its own density, compressed and then forced through the holes in the die. Compression Area is where the converted material feedstock is compressed to near pellet density with the entrained air forced out. Extrusion Area is where the converted material feedstock has reached pellet density and is forced through the die holes.

The forming process in the mill is quite power intense as the feedstock is forced into a die and extruded. The temperature and pressure generated contribute in causing the wood to bind together. The pressure between the roll and the pellet mill die are quite high. As is known in the art, the pressures generated in the process may vary between 20,000 to 45,000 newton per sq cm (30,000 to 65,000 psi), depending upon the characteristics of the various wood species, feedstock preparation, moisture and the final pellet hardness required.

The pellet mill discharges the hot, moist, fully formed but soft pellets to an ambient air cooler. After the pelletizing process, the temperature of the pellets are normally around 60 to 80 degrees F. The cooling process, thus, facilitates storage and transport of the pellets. Once cooled, the pellets become a hard durable product that is readily movable with standard material handling equipment.

FIG. 4 illustrates another example of a manufacturing process that is suitable for utilization of the gas turbine generator system of FIG. 1. The process shown in FIG. 4 relates generally to the manufacturing of construction materials, specifically to the manufacturing of drywall board. Drywall is a construction material consisting of thin panels of gypsum board.

The board is composed of a layer of gypsum rock sandwiched between two layers of special paper. In addition to being easy to install, drywall provides a measure of fire protection to buildings. Gypsum contains large amounts of water bound in crystalline form. For example, 10 square feet (1.0 sq m) of gypsum board may contain over 2 quarts (2 liters) of water. When exposed to fire, the water in the gypsum board vaporizes, with the temperature of the panel remaining at 212°F (100°C) until all of the water is released. This protects the underlying wood framework in constructions sites. Even after all of the water evaporates, the gypsum itself will not burn and continues to provide substantial fire protection. This is why drywall panels are widely utilized in modern construction around the world.

The primary component of drywall is the mineral gypsum. Gypsum is a light-density rock found in deposits worldwide. Each molecule of gypsum (dihydrous calcium sulfate) is composed of two molecules of water (H2O) and one of calcium sulfate (CaSO4). By weight, the compound is 21% water, but by volume it is nearly 50% water.

The water present in gypsum is in crystalline form making the material dry. The water bound in the gypsum molecules remains solid unless it is heated to 212°F (10O⁰C)₅ at which point it changes to a gaseous state and evaporates. Gypsum that has been crushed and heated to remove 75% of its water content is known as plaster of Paris. When water is added to this fine white powder, the resulting material is easily molded into any desired shape. Upon drying, the reconstituted gypsum regains its rock-like qualities while retaining the desired shape. Two types of paper are normally used in the production of most drywall: l)Ivory manila face paper and 2) gray back paper. Both of these types of paper are made from recycled newspaper. The ivory manila face paper, when properly primed, readily accepts most paints and other types of wall finishing products. The gray back paper can be laminated with aluminum foil to produce a special type of drywall that resists the flow of water vapor in environments like bathrooms.

Specialized varieties of gypsum board might be made with different types of paper. The manufacturing process of drywall papers make the utilization of the gas turbine generator system ideal. Fabrication of drywall generally consists of placing the gypsum core material between the two layers of paper, drying the product, and finishing it into panels of standard size.

To begin the process, the core material is formed. Depending upon the variety of drywall being produced, certain additives may be blended with the plaster of Paris that will form the core of the drywall. Each additional ingredient amounts to less than one half of one percent of the amount of gypsum powder. Starch may be added to help the paper facings adhere to the core, and paper pulp may be added to increase the core's tensile strength. Unexpended vermiculite may be added when producing fire-resistant grades of gypsum board. In some examples, clay may also be added.

Next, water is normally added to the plaster of Paris mixture to form a slurry of the proper consistency. An asphalt emulsion and/or a wax emulsion may be added to achieve the desired level of moisture resistance in the final product. A foaming agent such as a detergent may be included. During the mixing process, air becomes entrained into the material. In a conventional process, the finished gypsum panel will be over 50% air, minimizing the board's weight and making it easier to cut, fit, and nail or screw to framing. Glass fibers may be added to the wet core material when making firerated gypsum board.

As shown diagrammatically in FIG. 4A, the gypsum slurry is poured onto a layer of paper that is unrolled onto a long board machine. Another layer of paper is unrolled on top of the slurry. The sandwich is then passed through a system of rollers that compact the gypsum core to the proper thickness. The most common thicknesses are 0.37 inch (9.5mm), 0.5 inch (12.7mm), and 0.62 inch (15.7mm). As the drywall continues along the conveyor belt, the edges are formed. Various shapes of edges are possible, depending on the final use of the panel. By the time the edges have been shaped, the plaster core will have set sufficiently for slicing the continuous strip into standard panel sizes. The drywall board, generally 48 inches (1219mm) or 54 inches (1572mm) in width, is usually cut into panels that are 8 feet (2400mm) or 12 feet (3600mm) in length.

Conventionally, the panels are transferred to a conveyor line that feeds them through a long, drying oven that is a gas-fired oven. The panels normally enter the oven at 500⁰F (260°C) and are exposed to gradually decreasing levels of heat during the 35-40 minutes they travel through the system. These parameters and conditions make it ideal to utilize the gas turbine generator system of the present disclosure in the dehydration step of drywall production. The exhaust from the gas turbine can replace conventional sources such as gas-fired ovens as the gas turbine generator system is retrofit into existing drywall board production facilities, solving the need for more efficient and lower cost water removal and dehydration technologies. Utilizing direct exhaust heat from the gas turbine, 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 temperatures set forth herein prevents significant oxidation of the materials 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 system before being released into the atmosphere. After emerging from the drying oven, the dry wall panels are bundled, ready to be shipped.

FIG. 5 illustrates yet another example of a manufacturing process that is suitable for utilization of the gas turbine generator system of FIG. 1. The process shown in FIG. 5 relates generally to the manufacturing of medicinal products, specifically to the manufacturing of dry powder pharmaceuticals that can be inhaled as aerosols, filled into capsules or pressed into tablets for oral applications.

Although medicinal products are available in a wide variety of forms, the gas turbine generator system of the present disclosure may be suitable for types of medicines or pharmaceuticals that are normally processed as powders, either in final form or as intermediate products. The gas turbine generator system of the present disclosure may be used to replace conventional dehydration systems that are normally utilized in producing such powdered pharmaceuticals.

According to one example production process, active ingredients of a medicinal drug and additives such as excipients, binders, plasticizers, etc. are fed into a granulator/chopper system. The components of the granulator are configured to optimize mixing and granulation to achieve the desired structure for the active ingredients and additives being granulated. In addition, venting devices may be utilized at the feedstock entry point to remove entrapped air and to maximize the product throughput. The granulator may use liquids to heat and cool the granulation and to provide uniformity in temperature and better temperature control.

The granulation may exit the granulator in a wet condition. The discrete granulation particles may be passed through a screen and then leveled and deposited onto a conveying system. The conveying system may include a conveyor belt that is configured to transport the particles to a drying/dehydration unit. Conventional pharmaceutical drying operations utilize driers such as spray dryers, paddle dryers, fluidized bed dryers, media slurry dryers, and tornesh dryers and utilize conventional heat sources such as gas burners, dielectric energy, such as RF or microwave energy. For example, in a drying/dehydration unit that uses dielectric energy as the heat source, RF is used between two electrodes positioned on opposite sides of the apparatus. As the granulation enters the portion of the drying apparatus containing the electrodes, the material to be dried is acted upon by the alternating electric field created by the electrodes which heats the material. The friction caused by constant reorientation of water molecules under the influence of the alternating electric field between the electrodes causes the water in the material to rapidly heat and evaporate. Water vapor may be removed from the top and bottom of the surface of the conveyor belt by process air that flows in co-current or counter current streams. The moisture level of the material gradually decreases as the material is moved through the drying apparatus. During drying, the bed can be maintained at a temperature range determined by the nature of the product. In one embodiment, this may be within about a 30 degree range, such as from about 75 degrees C to about 105 degrees C. In a conventional system such as this described, typical residence times may vary from several minutes to a few hours, depending on the required inlet and outlet moisture levels, the properties of the product, and the required product output.

The process parameters of most pharmaceutical production systems makes the gas turbine generator system of the present disclosure an ideal dehydration system for use therein. The exhaust from the gas turbine can replace conventional sources such as gas burners and dielectric energy as the utilized heat source as the gas turbine generator system is retrofit into conventional systems, solving the need for more efficient and lower cost water removal and dehydration technologies. Also, according to other embodiments, the electricity generated by the generator of the gas turbine generator system can be utilized in supplementing a dielectric dehydration system as described above.

By utilizing direct exhaust heat from the gas turbine, 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 temperatures set forth herein prevents significant oxidation of the pharmaceutical materials in the dryer vessel, preserves the maximum active ingredient value in the feedstock for containment in the end product. 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 system before being released into the atmosphere. In addition, the dryer vessel need not provide direct contact of the turbine exhaust gases and the pharmaceutical feedstock, but can provide indirect heating of the high water content feedstock to achieve the drying and/or thermal treatment/conversion/alteration desired if degradation of the feedstock is going occur by direct contact of the exhaust gases. FIG. 6 illustrates yet another example of a manufacturing process that is suitable for utilization of the gas turbine generator system of FIG. 1. The process shown in FIG. 6 relates generally to the processing of food products, specifically to the processing of food products that are consumable as everyday snacks such as potato chips. An example production process for producing chips made out of corn is shown in FIG. 6A.

Dehydration is an essential production step in processing snacks such as potato or corn chips. According to an example production process used by Frito- Lay, Inc., located in Dallas, Texas, commercial production of potato chips typically involves a continuous or batch process wherein sliced potatoes are introduced into a vat of frying oil at a temperature of around 365 degrees F or higher. The slices are conveyed through the oil by paddles or other means and removed from the oil after about 2-3 minutes of frying when the moisture content of the chips have been reduced to about 2% by weight or less.

Conventionally, dehydration may be an essential step that is used in pre- frying processes in the production of potato chips. Dried or dehydrated potato solids will generally have a moisture content of about 15 weight percent. Since the dried potato solids have a low moisture content, they are relatively light in weight and can be economically and conveniently shipped to various processing locations. Dried potato solids are also quite storable when containerized and are thereby preserved from undue physical and chemical change before they are further processed.

It is known that potatoes having a high reducing sugar content can exhibit unwanted browning upon frying. To reduce the browning characteristics, those potatoes that have an undesirably high reducing sugar content can be formed into acceptable fried products by fermenting the potatoes in dough form to lower their reducing sugar content before frying. Although the dough can be made by directly dehydrating precooked potatoes to the required moisture content, it is in some instances advantageous to prepare the dough by the use of highly dehydrated potatoes, e.g., potato flakes or potato granules, which have a moisture level below that needed to form a dough. These potato solids can then be rehydrated or combined with high moisture potato solids to provide a dough of desired consistency, which frequently has a moisture content of about 25 to 60 weight percent. The gas turbine generator system of the present disclosure is ideal for these pre-frying processes.

Conventionally, dehydration is also used in post-frying processes in the production of potato chips. For example, dehydration may be used to convert the fried potato chips to low-oil potato chips. According to certain example processes, to produce low-oil potato chips, once fully fried and removed from the friers, the potato chips may be exposed to superheated steam to de-oil the slices.

According to another conventional production method, instead of being fully fried, the potato slices may be partially fried to a moisture content of between 3 and 15 weight percent. The par-fried potatoes, then, may be exposed to hot air blasts at between 250 degrees F and 350 degrees F to reduce the oil content while also finish- drying the slices to a moisture content of below 2 weight percent to produce low-oil potato chips. Instead of hot air blasts, the potato slices may be finish-dried with radiant energy according to other example processes. It is important to conduct all of the post-frying processing in an essentially oxygen free atmosphere, making the utilization of the gas turbine generator system of the present disclosure ideal for a number of these post- frying processes performed in manufacturing potato chips. Describing the de-oiling process in further detail, the potato slices reside within the frying medium until the slices have been partially fried to an average moisture endpoint of between about 4 and 10 weight percent, based on the total weight of the par-fried potato slices. Preferably the slices are par-fried to an average moisture end point of between about 5 and 8 weight percent, based on the total weight of the par-fried potato slices. Par-fried potato slices having average moisture contents of between about 4 and 10 weight percent are also characterized as having oil contents ranging from about 28 to about 40 weight percent, based on the total weight of the par-fried potato slices, upon removal from the fryer.

Once the desired par-fried moisture content has been reached, the potato slices are removed from the frying medium and conveyed to a de-oiling unit. According to conventional processes, the de-oiling unit may comprise an enclosed region wherein superheated steam is forced through a bed of par-fried potato slices to strip oil from the potato slices. The temperature in this region may be maintained at from 300 degrees to 340 degrees F. The superheated steam may be injected into the de-oiling unit by any known means such as a directed curtain of superheated steam, by a plurality of spaced-apart, directed nozzles, or by injection of steam into a space nearby the bed of potato slices and utilizing heater and blower means to ensure that the steam is superheated and to direct the superheated steam towards the bed of potato slices. As discussed previously, the gas turbine generator system of the present disclosure may be used to provide the steam or superheated steam for this portion of the de-oiling process, rather than being utilized as a dehydration-only system.

In all of the post-frying processes, it is desirable that the oxygen content in the production units be controlled. With the use of superheated steam, oxygen may be maintained at a reduced level, such as at a level of about 14 volume percent or less without significantly affecting the shelf life of the finished products. The reduced oxygen level may be between about 3.0 and 3.5 volume percent of the atmosphere within the de-oiling unit, or as low as about 0.5 volume percent of the atmosphere within the de-oiling unit. A reduced oxygen atmosphere enhances the ability to recover and reuse the oil that is stripped from the par-fried slices since oxidative degradation of the oil is reduced with lesser concentrations of oxygen in the atmosphere. The potato slices are maintained in the de-oiling unit for a time sufficient to reduce the oil content of the slices to less than 25 weight percent based on the total weight of a de-oiled slice having a moisture content of about 2 weight percent. The stripped oil is recoverable and may be separated from the aqueous and solid residuals for alternative uses including recycle to the fryer. The residence time of a potato slice in the de-oiling unit may be generally from about 30 to about 120 seconds.

The de-oiling unit may be employed to obtain optimal de-oiling efficiencies and, it may remain necessary to further reduce, and ensure uniformity of, the moisture content of the par-fried and de-oiled potato slices to produce high quality low oil potato chip products. This further dehydration step is conventionally accomplished by conveying a bed of par-fried and de-oiled potato slices through a dehydrating unit that is maintained at a temperature of from about 240 degrees to 320 degrees F. A lower dehydration rate is important in the dehydrating unit to decrease the potential of producing finished potato chips having burnt flavors.

In conventional processes, the dehydrating unit is operable with methods for reducing the moisture content of the potato slices, such as radiant heat, microwave energy, dielectric drying, forced hot air produced by gas burners, and superheated steam. The potato slices remain in the dehydrating unit until the final moisture content of the so-formed potato chips is uniformly reduced to between 0.8 and 2.0 weight percent, based on the total weight of the formed potato chips. Preferably the final moisture content of the potato chips is between about 1.0 and 1.5 weight percent. The residence time of a potato slice in a dehydrating unit generally ranges from about 60 to 180 seconds, varying as a function of the raw material potato characteristics and the slice thickness and configuration. The parameters employed in the dehydration processes described above make the gas turbine generator system of the present disclosure an ideal system for retrofitting into conventional dehydration units or equipment.

In production of potato chips, the fryer, de-oiling unit and dehydrating unit may be integrated, contiguous units or may be separate with the potato slices transferring between these units by conveying means, such as endless belt conveyors. Preferably, any conveying means between the fryer and the de-oiling unit and between the de-oiling unit and the dehydrating unit is covered to reduce the exposure of oil to oxygen and to retain the heat content present in the potato slices.

Dehydration is also an essential production step in processing chips made from corn (see FIG. 6A). Corn is a staple source of food in Mexico and in parts of Central America, and there is global demand for corn products such as corn chips, tortilla chips, tacos, tostadas and enchiladas. Many of these corn products are derived from masa dough (hereinafter, masa).

Corn products can be made from either wet masa, often called fresh masa, or dry masa flour (hereinafter, dry masa). In general, dry masa produces less desirable, lower quality products than wet masa. For example, dough derived from dry masa or low moisture-content masa tends to be less plastic and cohesive than wet masa or high-moisture-content masa. The more desirable wet masa, however, deteriorates quickly due to its high moisture content. Consequently, dry masa is often used to make corn products because of its longer shelf-life and transportability. Manufacturers can simply rehydrate dry masa to create masa dough rather than nixtamilize and grind fresh corn. Furthermore, dry masa may be more suitable in cooking applications where it is more desirable for the masa dough to be buoyant in cooking oil, as dough made from dry masa tends to be less dense than dough made from wet masa.

The traditional method for processing fresh corn to form masa dough is called nixtamilization. In a traditional nixtamilization process, fresh whole-kernel corn is first soaked in a solution of water and lime (calcium hydroxide) and then partially cooked at or near the boiling point for a short time depending on the hardness of the corn. The corn is then steeped in the lime-water solution and is allowed to cool for about 8-12 hours in order to loosen and degrade the pericarp (or bran) which is the outer, fibrous layer of a corn kernel. Cooking and steeping in alkaline solution causes partial dissolution of the cuticle and other pericarp layers as well as swelling and weakening of cell walls and fiber components. The corn kernels are then drained of the cooking liquor (called "nejayote"), which contains loosened pericarp and other dissolved or suspended particles, and the corn kernels are washed to remove excess lime and loose particles. Typically, up to 15% by weight of the total corn fraction may be lost during the cooking and washing steps.

The corn kernels are then stone-ground to disrupt the starch-containing cell structures. The ground, wet mixture can be mixed with water to form fresh masa dough, or it can be dehydrated in a dehydration process and ground to form dry masa flour. The ground mixture typically has a moisture content of approximately

30-50% by weight. Dry masa flour can be rehydrated at a later time to form masa dough.

According to one example process, once the dough is cut into desired units, the units are then toasted in a toasting stage. In conventional practice, the toasting stage may involve exposing the cut units to conductive, convective and/or radiant heat.

Direct conductive heat can be applied to the cut units in the toasting stage by placing the units directly on a hot oven pan or passing them along a hot conveyor belt through an oven. Other methods of providing conductive heat include, but are not limited to, directly contacting the units with heated ceramic hearthstone, firebrick or composite hearth.

A conventional convective heat source can be provided from any cooking device in which currents of hot air transfer heat to the surface of the food. Ovens or toasters using natural or forced convection can be used.

An infrared oven or burner can also be used in the toasting stage to further brown the units. An infrared burner may typically comprise of a plurality of porous ceramic plates or metal screens upon which premixed air and gases are combusted.

The combustion may provide high surface temperatures to the infrared burner, which can often reach 1800 degrees F. and causes the burner to emit radiant heat. Alternatively, combination ovens such as a hot-air/infrared oven can also be employed. Such ovens are configured to provide various combinations of conductive, convective and radiant heat simultaneously. In the toasting stage, the units are cooked to reduce the moisture from roughly 50% by weight to a moisture content ranging from about 0.5% by weight to about 15% by weight, depending on the desired amount of browning. Thus, based on the parameters of the cooking/toasting processes, the gas turbine generator system is not only suitable in the production of dehydrated masa flour but also in the cooking/toasting processes.

In certain embodiments, the units can be fried in hot oil after being toasted in a toasting stage. Thereafter, similar processes described above for producing low-oil potato chips may be utilized in de-oiling the corn chips. While we have illustrated and described various manufacturing processes in various different industry segments that may utilize the gas turbine generator system of the present disclosure, as described previously, there may be other processes or industries that are ideal for retrofitting standard dehydration systems with the gas turbine generator system of the present disclosure. The example processes described herein should not be used to limit the scope and the inventive features of the disclosure. The embodiments of the disclosure are by way of illustration only and various changes and modifications may be made within the contemplation of the inventive aspects and within the scope of the following claims.

Claims

Claims:

1. A method for producing pelletized bio fuel, the method comprising:

- providing bio fuel feedstock; - grinding the bio fuel feedstock;

- providing at least one gas turbine configured to produce exhaust gases;

- contacting the exhaust gases produced by the at least one gas turbine with the ground bio fuel feedstock for a sufficient time to produce a dried material having a moisture content less than the feedstock; and - pelletizing the dried material.

2. A method according to claim 1, wherein the pelletized bio fuel includes wood pellets.

3. A method according to claim 1 , wherein the gas turbine comprises a gas turbine generator.

4. A method according to claim 1 , further providing a dryer vessel adapted to receive the exhaust gases from the gas turbine through a connection and adapted for receiving the ground bio fuel feedstock, wherein the connection is adapted to substantially preclude introduction of air into the dryer vessel.

5. A method for producing drywall, the method comprising:

- providing a core mixture material including mineral gypsum; - placing the core mixture material between two layers or paper;

- compacting the core mixture material between the two layers of paper to produce a compacted material;

- providing at least one gas turbine configured to produce exhaust gases; and

- contacting the exhaust gases produced by the at least one gas turbine with the compacted material for a sufficient time to produce a dried material having a moisture content less than the compacted material.

6. A method according to claim 5, further comprising cutting the dried material into panels.

7. A method according to claim 5, wherein the gas turbine comprises a gas turbine generator.

8. A method for producing dry powder pharmaceuticals, the method comprising:

- providing a mixture of active ingredients of a medicinal drug and additives;

- granulating the mixture;

- screening the granulated mixture to produce a deposit; - providing at least one gas turbine configured to produce exhaust gases; and

- contacting the exhaust gases produced by the at least one gas turbine with the deposit for a sufficient time to produce a dried material having a moisture content less than the deposit.

9. A method according to claim 8, further comprising conveying the deposit to a dryer vessel adapted to receive the exhaust gases from the gas turbine.

10. A method according to claim 9, wherein the dryer vessel is connected to the gas turbine through a connection that is adapted to substantially preclude introduction of air into the dryer vessel.

11. A method according to claim 8, wherein the gas turbine comprises a gas turbine generator.

12. A method of producing a food product, the method comprising:

- providing a raw food feedstock;

- providing at least one gas turbine configured to produce exhaust gases; and

- contacting the exhaust gases produced by the at least one gas turbine with the feedstock for a sufficient time to produce a dried material having a moisture content less than the feedstock; and

- at least partially frying the dried material in oil.

13. A method according to claim 12, wherein the raw food feedstock includes potatoes.

14. A method according to claim 12, further comprising exposing the at least partially fried material to superheated steam to reduce the oil content thereof.

15. A method according to claim 14, further comprising contacting the reduced- oil material with exhaust gases produced by a gas turbine.

16. A method according to claim 12, wherein the raw food feedstock includes wet masa formed from corn.

17. A method according to claim 12, wherein the gas turbine comprises a gas turbine generator.

18. A method according to claim 12, further providing a dryer vessel adapted to receive the exhaust gases from the gas turbine through a connection and adapted for receiving the feedstock, wherein the connection is adapted to substantially preclude introduction of air into the dryer vessel.

19. A method of modifying an existing manufacturing facility that includes a dehydration unit, the method comprising:

- replacing the existing dehydration unit with a gas turbine system including a gas turbine configured to produce exhaust gases and a dryer vessel, wherein the dryer vessel is adapted to receive the exhaust gases from the gas turbine through a connection adapted to substantially preclude introduction of air into the dryer vessel.

20. A method according to claim 19, wherein the gas turbine system includes a gas turbine generator.