INCORPORATION BY REFERENCE

[0001] The following US Provisional applications are incorporated by reference as if fully set forth herein: 61/596,440; 61/596,467; 61/596,489; and 61/596,503 all filed on February 8, 2012.

BACKGROUND

[0002] One method for disposing of organic waste like animal manure, poultry litter, digestate from anaerobic methane digesters and even agricultural biomass is gasification and/or combustion for the recovery of heat and nutrients. One established process is called Ecoremedy®, described in US patent 6,948,436 to Mooney, which is incorporated by reference as if fully set forth herein. One challenge facing fertilizer production from manure and litter is environmental legislation prohibiting or severely limiting the use of raw manure and poultry litter as a fertilizer due to concerns about soil nutrient loading levels.

[0003] Excessive amounts of nitrogen and phosphorous applied to the soil may result in the overfertilization (pollution) of waterways causing ecological and environmental damage. Thus, the quantity of raw animal manure, processed biosolids from waste water treatment plants, digestate from methane digesters and poultry litter that cannot be land applied locally due to over-fertilization is being hauled to non-contaminated areas for land application. The practice of hauling the waste product to areas beyond the "contaminated area" results in expensive freight charges and the expansion of the "contaminated area." The production of animal and human manure and poultry litter may continue to increase with the growth of the world population.

[0004] Gasification and combustion are methods often used for solid waste disposal suited for waste materials with less than 50% moisture content. High liquid wastes such as sludge, waste water treatment solids (Biosolids), raw animal manure (dairy cows, hogs), and coarse pressed solids from anaerobic digestion systems, may be too wet for use as a fuel in gasifiers or furnaces and often contain noxious odiferous chemical compounds like ammonia (NH3).

SUMMARY

[0005] The embodiments contained herein are intended to be used directly with the Mooney technology but are useful in association with other gasification or combustion techniques or as a stand-alone material processing component. The methods and apparatuses described herein improve upon the environmental benefits offered by Mooney, as well as other gasification and/or combustion systems, by broadening the envelope of materials qualifying as available feedstock for energy generation to include high liquid wastes and by recovering nitrogen for beneficial purposes.

[0006] An apparatus for converting organic waste fuel into energy includes a moving grate that moves organic waste fuel through the apparatus from a first conditioning chamber to a second gasification chamber; in the first conditioning chamber, oxygen- depleted flue gas moves through the waste fuel to produce ammonium and water vapor that is removed from the first conditioning chamber; in the second gasification chamber, the waste fuel is exothermally converted to an oxygen- depleted flue gas for use in the conditioning chamber without the use of any external or supplemental ignition source; and a guillotine gate that separates the first chamber and the second chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a cutaway side view of the apparatus for conditioning fuel according to the invention.

[0008] FIG. 2 is an enlarged detail of the cooling rail apparatus used to preheat conditioning air and cool the refractory close to the fuel bed in the gasifier. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

INTRODUCTION

[0009] The embodiments herein broaden the spectrum of acceptable fuels for gasification and combustion to include high liquid wastes by conditioning the high liquid waste materials to a form acceptable for gasification and combustion while capturing valuable chemical constituents within the wastes for beneficial use. By removing the moisture and ammonium (NH4+) before the gasification chamber and reintroducing the water vapor and NH4+ in the oxidizer, the range of eligible fuels to be gasified may be expanded and the water vapor and NH4+ may be used to reduce nitrogen oxides (NOx), a criteria air pollutant. It is also possible to recover nitrogen from the water vapor and NH4+ gas emitted from the liquid waste in a conditioning chamber to create a renewably sourced nitrogen fertilizer.

[0010] Further, removing water from the waste material may create an improved fuel for the gasifier and may allow for the reduction in the size of the active grate within the gasifier needed to convert the carbon in the fuel to energy. Moreover, removal of water from fuel enables a higher energy content syngas to be produced in the gasifier which broadens the selection of eligible energy conversion devices to include reciprocating engines, gas turbines, rotary engines, or systems for converting syngas to another form of fuel such as liquid fuels. This water removal may also improve the uniformity of the fuel entering the gasifier.

[0011] The apparatuses and methods herein dry the organic waste material and capture the NH4+ to use for NOx reduction or as a source of nitrogen fertilizer while simultaneously improving the conditions within the gasification chamber by minimizing the edge effect of refractory which contributes to slagging and uncontrolled gasification or combustion.

[0012] As shown in FIGS. 1 and 2, a portion of the downstream flue gas and/or ambient air 300 is extracted using a forced draft fan (not shown) and ducted through hollow cooling rails 109 located at the base 110 and in the side walls 111 of the gasifier 200. The flow of the thermal fluid 300 cools and extracts heat energy from the refractory 112 and gasifier chamber 200 creating a localized cooling effect along the sides of the gasifier 111 and on the edges 115 of the fuel 600 being gasified. This localized cooling reduces the propensity of the material to slag, creates a more uniform fuel pile profile with a leading edge extending the full width of the gasifier 200, reduces the amount of thermal growth of the steel structure supporting the gasifier 440 and cools the metal conveyor 400 used to transfer the fuel 600 through the gasifier 200.

[0013] When air or flue gas (from the gasification chamber 200 cooling rails

109) is used as the cooling thermal fluid, the now-heated gas may be reused in the gasification chamber 200 (see arrow indicating flow of fluid away from the conditioning chamber 100 in FIG. 1). Since this fluid may be oxygen- depleted and ignition takes place in the gasification chamber 200, some ambient or other oxygenated air may be needed in the gasification chamber 200, that is, the flue gas alone will likely not be adequate in the gasification chamber 200 because it may be oxygen- depleted.

[0014] The flue gas may also enter the conditioning air zones 310,312 located beneath and around the fuel bed 600 of the conditioning chamber 100 preceding the gasification chamber 200 (see flow of flue gas indicated in FIG. 1 towards conditioning chamber 100). If liquid, the thermal fluid is pumped through the cooling rail conduit 109 and then through an air to liquid heat exchanger with the heated air being sent to the conditioning chamber air zones 310,312. This hot conditioning gas 300 is forced through the pile of incoming wet fuel 600. The hot, dry gas heats the fuel, vaporizes ammonium and water in the fuel 600. This stream of moist, ammonium rich gas 700 is then ducted directly into the oxidizer 800 where it reacts with the NOx in the combusted gases converting it to N2 and H20 or into another separate system (not shown) for recovering the valuable nitrogen for use in fertilizers or other purposes.

[0015] By diverting water vapor and ammonium from the conditioning chamber 100 directly to the oxidizer 800, the producer gas generated in the gasifier 200 is highly concentrated and may be used for combustion in reciprocating engines, gas burners, gas turbines, and other electricity or combustion devices if desired. The pre-drying may also increase the heat release per unit area of the gasifier grate making it more efficient and requiring a smaller grate surface. An adjustable guillotine gate 103 or other leveling device evenly distributes material into the conditioning chamber 100 and is used to isolate the conditioning chamber 100 from ambient thereby containing vaporized gases. Another adjustable guillotine gate 107 or other leveling device 107 is located between the conditioning chamber 100 and the gasifier 200 isolating potential localized pressure differences between the two chambers 100, 200. This pressure isolation curtain 107 also serves to level the fuel bed as it enters the gasification chamber 200 to provide a more uniform fuel feed into the gasifier 200. An added benefit of this method and apparatus is that the conditioning chamber 100, because of its oxygen- depleted environment, creates a buffer between the hot gasifier 200 and the unprocessed, potentially flammable, fuel in the loading area 900 preceding the conditioning chamber 100.

[0016] The apparatus for conditioning high moisture organic waste into a usable solid fuel while capturing the NH4+ includes a waste loading area (near 900) for loading waste 600 onto a moving or tumbling conveyor grate 400 that moves the waste 600 through the apparatus from the waste loading area 900 to the conditioning chamber 100 and then to the gasifier 200. A level control device or guillotine gate 103 controls the amount of waste 600 that moves from the loading area 900 to the moving conveyor 400; a perforated stationary plate 500 located beneath and around the moving conveyor 400 with the waste 600 thereon that allows air to pass through perforations to the waste on the moving conveyor 400. The apparatus also has at least one controlled conditioning air zone 310 that directs air with a substantially controlled temperature through the stationary plate to the waste 600 on the moving conveyor 400. At least one nozzle 303 directs air to the conditioning air zone 310 below and around the moving conveyor 400. A level control device 107 controls the amount of waste 600 that exits from the conditioning chamber 100 on the moving conveyor 400. An exhaust duct 108 channels the NH4+ and water vapor to either the oxidizer 800 for use as a NOx reducing agent or a collection point for converting the NH4+ to nitrogen fertilizer. Cooling rails 109 preheat conditioning air and simultaneously cool the sides of the gasification chamber 200 thereby extending the life expectancy of grate metallurgy and reducing clinkers.

DESCRIPTION

[0017] The apparatus and process described herein conditions organic waste such as animal waste, human waste, poultry litter, pressed coarse solids from anaerobic methane digesters (digestate), biomass (organic matter available on a renewable basis such as forest and mill residues, agricultural crops and wastes, wood and wood wastes, animal wastes, livestock operation residues, aquatic plants, fast-growing trees and plants, and municipal and industrial wastes), or combinations thereof as a fuel to produce thermal energy, organic and/or all natural recovered nitrogen fertilizer , and/or a gaseous fluid for reducing nitrogen oxides (NOx) emissions occurring during combustion. This use for a generally discarded waste turns what is now considered a liability into a revenue stream.

[0018] The conditioning apparatus/chamber 100 is located between the material feed hopper (not shown, but near 900) of the gasifier and the gasification chamber itself 200 and comprises a level control device or gate 103 for controlling the volume of waste 600 that moves from the metering bin into the conditioning chamber 100 via the moving conveyor 400. A perforated stationary plate 500 located beneath and around the moving conveyor 400 with the waste 600 thereon allows air to pass through perforations to the waste 600 on the moving conveyor 400. At least one controlled conditioning air zone(s) 310, 312 directs air with a substantially controlled temperature through the stationary plate 500 to the waste 600 on the moving conveyor 400.At least one nozzle 303 directs air to the conditioning air zone 310 below and around the moving conveyor 400. A level control device 107 controls the amount of waste 600 that exits from the conditioning chamber 100 on the moving conveyor 400. An exhaust duct 108 channels the NH4+ and water vapor to either the oxidizer 800 for use as a NOx reducing agent or a collection point for converting the NH4+ to nitrogen fertilizer. Cooling rails 109 to preheat conditioning air and simultaneously cool the refractory sides 112 of the gasification chamber 200 thereby extending the life expectancy of grate metallurgy and reducing the production of clinkers.

[0019] The organic waste fuel 600 is conveyed into the appartus via a material storage and handling system (not shown) using, for example, a silo with un-loader or fuel building with a walking floor system to a belt and vibratory conveyor system designed specifically for the characteristics of the fuel. The fuel is conveyed into a metering bin (not shown) located at the entrance to the apparatus. The fuel metering bin may be located directly above the moving conveyor 400 which may continuously convey waste into the apparatus 100. The high temperature moving conveyor 400 may be an open weave/mesh design, or any other conveyor that permits air passage through itself (e.g.. bars, rods, auger), allowing conditioning air to pass through a perforated stationary plate 500 into the fuel bed 600. The pressure drop across the perforated plate 500 may be significant relative to the pressure drop through the fuel bed 600. Controlling the pressure drop through the perforated stationary plate 500 ensures uniform distribution of conditioning air despite quantity, moisture and bulk density variability within the fuel bed 600.

[0020] The moving conveyor 400 pulls the fuel 600 into the conditioning chamber 100. The moving conveyor 400 may be a positive drive design. The moving conveyor 400 may move at a rate of linear travel between 2.5 feet per hour to 25 feet per hour, although other speeds are possible, and may be driven by a variable speed motor (not shown).

[0021] The fuel 600 on the moving conveyor moves through a guillotine level control gate 103. The guillotine gate assembly 103 is adjustable and used to control the bed depth of the fuel 600 (as seen in FIG. 1, guillotine gate assembly detail where the fuel depth is high on the right side of the guillotine gate and lower on the left side of the same gate).

[0022] As shown in FIG. 2, ambient air or oxygen deficient gas (flue gas) is heated by passing through the cooling rails 109 into the air plenum 306 before being introduced into the conditioning chamber 100 underneath the stationary plate 500 and forced through the fuel bed 600 using a force draft fan (not shown).

[0023] The perforated stationary plate 500 may be sectioned into separate and discreet controllable air zones 310. 312. Each conditioning air zone may extend the full width of the conditioning chamber 100 and all conditioning air zones collectively may comprise the full length of the conditioning chamber and end at the exit guillotine gate 107 located just before the gasification chamber 200. The number of controllable zones is determined by the capacity of the unit and the fuel characteristics. For example wetter fuels will require different settings than dry fuel. The conditioning zones dry the fuel at controlled temperature and drive off water vapor (H20) and ammonium gas (NH4+) prior to delivering the fuel to the gasification chamber 200 where gasification is continued in subsequent zones under conditions suited for the dry fuel source and reduced bed depth. Controlling the temperature within the conditioning chamber 100 allows finer control of the vapor generation, concentration of ammonium gas, and avoidance of the production of volatile organic compounds (VOCs) in the gas removed to the oxidizer 800.

[0024] The first zone 310 of the conditioning chamber 100 may have perforations in the stationary plate 500 comprised of holes and/or slots 502 that are sized, shaped and oriented to provide proper air distribution and pressure drop through the stationary plate 500. The pressure drop through the plate 500 provides air to all sections of the fuel bed even as the bed characteristics change as H20 and NH4+ are driven out of the wet solids in the conditioning process. The specific combination, orientation and location of holes and/or slots 502 in the perforated plate 500 are determined by the characteristics of the fuel in that section of the bed. For example, the wet fuel entering the first conditioning zone 310 may require a different amount of air and air pressure than the dry fuel in the subsequent zones like zone 312. The orientation and location of the holes reflect these changing requirements.

[0025] The conditioning unit 100 may be fabricated with industry standard materials, construction techniques and practices and controls systems. For example, carbon steel may be used for the external walls of the conditioning chamber apparatus 100. Industry standard welding and bolt assembly practices may be used to fabricate the shell 120. Select grades of stainless steel may be required within the apparatus to withstand areas of high temperature and corrosion due to the physical and chemical properties of the waste 600. Other industrial grade materials like insulation, gaskets and high temperature paints may also be used.

[0026] The gasifier chamber 200 may operate at temperatures between

1200 and 1400 degrees Fahrenheit causing the cooling rail apparatus 109 described herein to possibly operate at temperatures between 200 and 600 degrees Fahrenheit and the conditioning chamber 100 may operate at temperatures between 100 and 400 degrees Fahrenheit. Cooler operating temperatures may be used for materials with high carbon content to avoid the release of volatile organic compounds (VOC). Lower operating temperatures require larger conditioning chamber volume and grate surface.

[0027] The current Mooney gasifier may process animal and human wastes up to 40% moisture and biomass up to 50% moisture without any fuel conditioning necessary. Poultry manure or litter (manure with bedding, usually woodchips or rice hulls) is generally below 40% moisture coming directly from a farm. The fuel conditioning chamber 100 may increase the spectrum of possible feedstock for gasification to include sludge or separated solids from high liquid waste streams such as cow and swine manure and biosolids from waste water treatment plants (up to 75% moisture post separator) without the need for drying techniques requiring the use of fossil fuels and enables the capture of NH4+ for beneficial purposes.

EMBODIMENTS [0028] The following is a partial list of embodiments described herein.

[0029] Embodiment 1. An apparatus for converting organic waste fuel into energy comprising: a moving grate that moves organic waste fuel through the apparatus from a first conditioning chamber to a second gasification chamber; in the first conditioning chamber, oxygen- depleted flue gas moves through the waste fuel to produce ammonium and water vapor that is removed from the first conditioning chamber; in the second gasification chamber, the waste fuel is exothermally converted to an oxygen-depleted flue gas for use in the conditioning chamber without the use of any external or supplemental ignition source; and a guillotine gate that separates the first chamber and the second chamber.

[0030] Embodiment 2. The apparatus of embodiment 1, wherein the guillotine gate isolates localized pressure differences between the two chambers.

[0031] Embodiment 3. The apparatus of embodiment 1, wherein the guillotine gate controls an amount of waste fuel that moves from the first chamber to the second chamber.

[0032] Embodiment 4. The apparatus of embodiment 1, wherein the moving grate moves the waste fuel between the chambers.

[0033] Embodiment 5. The apparatus of embodiment 1, further comprising a perforated stationary plate located proximate to the moving grate with the waste fuel thereon that allows air to pass through perforations in the stationary plate to the waste fuel on the moving grate.

[0034] Embodiment 6. The apparatus of embodiment 5, wherein the perforations in the perforated stationary plate can be closed, open, or partially open, and thus restrict or promote air that passes to the waste fuel on the moving grate.

[0035] Embodiment 7. The apparatus of embodiment 5, wherein the perforations are non-uniform along the length of the perforated stationary plate.

[0036] Embodiment 8. The apparatus of embodiment 1, wherein the oxygen- depleted flue gas is heated by passing through cooling rails in proximity to the second chamber.

[0037] Embodiment 9. The apparatus of embodiment 1, wherein ammonium and water vapor removed from the first chamber are sent to an oxidizer.

[0038] Embodiment 10. The apparatus of embodiment 9, wherein the removed water vapor in the oxidizer is used to manage production of NOx by the apparatus.

[0039] Embodiment 11. The apparatus of embodiment 1, wherein the temperature in the conditioning zone is controllable.

[0040] Embodiment 12. The apparatus of embodiment 1, wherein controlling the temperature in the conditioning zone controls a concentration of ammonium in the removed gas.

[0041] Embodiment 13. The apparatus of embodiment 1, wherein controlling the temperature in the conditioning zone controls a concentration of volatile organic compounds in the removed gas.

[0042] Embodiment 14. The apparatus of embodiment 1, further comprising cooling rails through which the flue gas flows, the cooling rails located proximate to the second chamber; the flow of flue gas through the cooling rails cools an edge of waste fuel in the gasification area.

[0043] Embodiment 15. The apparatus of embodiment 14, wherein the cooling of the edge of the fuel reduces slagging in second chamber.

[0044] Although features and elements are described above in particular combinations, one of ordinary skill in the art may appreciate that each feature or element may be used alone or in any combination with the other features and elements.