Patents Assigned to Tennessee Valley Authority
  • Patent number: 4587358
    Abstract: One approach to improving storage stability, particularly that attribute characterized by reduction in the tendency for caking during storage of freshly prepared urea particles such as granules, is to treat the surface areas of the freshly prepared particles/granules with appropriate amounts and kinds of conditioning agents. This approach does not address the problem of increasing the hardness of the particles to impart improved high-strength characteristics thereto. A second approach to this problem of improving storage stability of urea granules is to admix and/or react certain anticaking and hardness improving additives into or with the urea melt prior to the solidification of urea particulates therefrom. The instant invention is directed to this second approach of imparting to the ultimately prepared urea particles both improved anticaking and hardness (as opposed to being easily crushed, i.e., friable) characteristics by means of addition to the urea melt of certain additives.
    Type: Grant
    Filed: August 26, 1985
    Date of Patent: May 6, 1986
    Assignee: Tennessee Valley Authority
    Inventor: Glenn M. Blouin
  • Patent number: 4571435
    Abstract: A process for the preparation of nitrogen fertilizers, especially oxamide, either indirectly or directly from oxalate esters, including the regeneration of the quinone oxidant utilized in the formation of the above esters. The process teaches preparation of oxamide, a potential slow-release nitrogen fertilizer via the oxidative carbonylation of alcohols with carbon monoxide in the presence of a catalytic amount of a platinum group metal salt and an optionally substituted quinone (substituted or unsubstituted 2,5-cyclohexadiene-1,4-dione) followed by ammoniation of the filtered reaction mixture at room temperature, or below. High yields of isolated oxamide were obtained by regulating the temperature and pressure during the oxidative carbonylation and maintaining essentially anhydrous conditions throughout the process. In addition, nearly quantitative yields of the hydroquinones (1,4-dihydroxybenzenes) are recovered for recycle along with the solvents, or for other commercial uses.
    Type: Grant
    Filed: December 3, 1981
    Date of Patent: February 18, 1986
    Assignee: Tennessee Valley Authority
    Inventors: Robert J. Radel, Jack M. Sullivan
  • Patent number: 4565625
    Abstract: A phosphate ore flotation process comprising subjecting a phosphate ore containing surface-activated silica and silicates to froth flotation in the presence of a fatty-acid collector, recovering the phosphate concentrate from the overflow; removing the fatty acid collector from the phosphate concentrate in the presence of a sulfuric acid deoiling agent; subjecting the phosphate concentrate to a reversed froth flotation in the presence of a silica collector and a modifier, said silica collector being an amine and said modifier being either alkyl diphosphonic acid, or being HF; removing the separated silica from the overflow; and recovering the phosphate product in the underflow. The process of the present invention not only overcomes the problems of activated silica flotation, but also results in greatly improved grade and/or recovery of phosphate product in comparison to present conventional phosphate ore flotation processing.
    Type: Grant
    Filed: December 10, 1984
    Date of Patent: January 21, 1986
    Assignee: Tennessee Valley Authority
    Inventors: Shuang-shii Hsieh, James R. Lehr
  • Patent number: 4557909
    Abstract: Phosphate rock is heated under controlled conditions to essentially eliminate organic impurities and sulfides from the rock and subsequently leached with water to substantially increase the porosity and surface area of the calcined solid and remove any traces of sulfide still remaining in the calcine. This process yields an improved calcined product rendered more suitable for acidulation to wet-process phosphoric acid and is beneficial for apatitic phosphate rocks possessing a moderate to high content of organic impurities and a high degree of carbonate substitution in the apatite crystal lattice.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: December 10, 1985
    Assignee: Tennessee Valley Authority
    Inventor: Alexander D. Mair
  • Patent number: 4531962
    Abstract: In the first embodiment of our invention, solution type fertilizers are produced by reacting phosphoric acid with urea-ammonium nitrate solution (35 percent CO{NH.sub.2 }.sub.2, 45 percent NH.sub.4 NO.sub.3, and 20 percent H.sub.2 O), and urea. In the second embodiment of our invention, the same solution is produced by reacting phosphoric acid with a urea-ammonium nitrate suspension that contains 36 percent nitrogen, 56 percent urea, and 29 percent ammonium nitrate. The ammonium nitrate portion of the nitrogen solution in said first embodiment reacts with the urea and phosphoric acid to produce urea nitrate (CO{NH}.sub.2.HNO.sub.3) and ammonium phosphate (probably NH.sub.4 H.sub.2 PO.sub.4). This solution contains rapidly available nitrate nitrogen as well as ammonium type nitrogen that is more slowly available than nitrate nitrogen. Similar results were obtained in said second embodiment when nitrogen solution and urea were reacted with sulfuric acid. The resulting solution contained CO(NH.sub.2).sub.2.HNO.
    Type: Grant
    Filed: June 4, 1984
    Date of Patent: July 30, 1985
    Assignee: Tennessee Valley Authority
    Inventors: Frank P. Achorn, Carl A. Cole, Jr.
  • Patent number: 4531571
    Abstract: Herein is described a method for feeding chlorine to a heat exchanger (condenser) for biological fouling control by targeting the feed to only a few tubes at a time. The assembly comprises a manifold surrounded by a seal which directly contacts the condenser tube sheet, thereby feeding chlorine to only a few selected condenser tubes at a time and the seal serves to restrict the flow of water through the tubes, thereby increasing the contact time between the chlorinated water and the fouling mass in the tubes. The manifold, powered by a pneumatic/hydraulic drive, moves across the entire condenser tube sheet so that all tubes are chlorinated for the same duration. A principal advantage of this system is that it allows the feed of relatively high concentrations of chlorine to the selected tubes, but is designed to meet EPA effluent limitations without dechlorination.
    Type: Grant
    Filed: April 23, 1984
    Date of Patent: July 30, 1985
    Assignee: Tennessee Valley Authority
    Inventor: Robert D. Moss
  • Patent number: 4512793
    Abstract: A process for direct granulation of unpurified urea phosphate from urea and merchant- or filter-grade wet-process phosphoric acid to produce a product with exceptional satisfactory physical and chemical properties for direct application to the soil or for use in production of fluid fertilizers. The process involves the utilization of sweep air in both the reactor and the granulator to remove water from the heat-sensitive urea phosphate mixture to enhance the granulation characteristics of the product. Product drying with applied heat after granulation is essentially eliminated. Moisture content of the urea phosphate is reduced to an acceptable level (about 1.0 percent) in the granulator; however, the granules are somewhat sticky. It has been found, however, that the resulting urea phosphate with about 1.0 percent moisture is less sensitive to heat than high (4 to 6 percent) moisture product. Consequently, heated air (up to about 200.degree. F.
    Type: Grant
    Filed: April 30, 1984
    Date of Patent: April 23, 1985
    Assignee: Tennessee Valley Authority
    Inventor: Cecil P. Harrison
  • Patent number: 4511388
    Abstract: An improved process for the production of highly concentrated (N-P.sub.2 O.sub.5) suspension fertilizers effected by the ammoniation of wet-process or other impure orthophosphoric acids in batch-type equipment. The underlying concept which goes to the gist of the instant invention involves the use of a heel of product from a previously prepared batch to provide nuclei and a suitable environment for the conversion of the metallic impurities therein into crystalline habits rather than the usual highly undesirable form of metallic impurity gel-like compounds, which gels cause extremely high viscosities, nonpourability, and complete destruction of fluidity in concentrated ammonium phosphate suspension fertilizers prepared by prior-art procedure.
    Type: Grant
    Filed: February 27, 1984
    Date of Patent: April 16, 1985
    Assignee: Tennessee Valley Authority
    Inventors: Thomas M. Jones, Lucian A. Kendrick, Jr.
  • Patent number: 4506453
    Abstract: An enhanced heat transfer process whereby solid particles are heated, dried, or cooled by a gas: Particles are repeatedly lifted and dropped as, for example, in flighted rotary drums. By forced recirculation, gas is passed through showering particles generally perpendicular to their plane of fall. Examples show gas forced to contact particles in this manner imparts an overall volumetric heat transfer coefficient to a rotary drum superior to that expected from classical literature or presently operating rotary drum heat exchangers. Disclosure teaches gas temperature adjustment between forced recirculations. Technique usage will reduce exchanger captial cost, increase energy efficiency, and reduce pollution problems. Also, prewetting of the particles in certain instances can be utilized to effect substantially increased pseudo volumetric heat transfer coefficients when cooling non-hygroscopic materials.
    Type: Grant
    Filed: September 20, 1983
    Date of Patent: March 26, 1985
    Assignee: Tennessee Valley Authority
    Inventors: Arthur R. Shirley, Jr., Frederick T. Carney, Jr.
  • Patent number: 4507139
    Abstract: The present invention relates to the reaction of phosphate rock with nitric acid and urea to produce nitrogen-phosphorus containing slurries, which slurries, in turn, may be granulated and dried to produce solid N-P fertilizer products with agronomically advantageous low pHs (1.0-4.0). The products have excellent storage characteristics. The improved properties of these products result partially from the formation of a new compound, Ca(H.sub.2 PO.sub.4)(NO.sub.3).CO(NH.sub.2).sub.2, which was discovered during the course of the investigation that led to the instant invention.
    Type: Grant
    Filed: October 26, 1984
    Date of Patent: March 26, 1985
    Assignee: Tennessee Valley Authority
    Inventors: Jack M. Sullivan, Yong K. Kim, Kjell R. Waerstad
  • Patent number: 4486301
    Abstract: A phosphate ore flotation process subjecting a phosphate ore containing carbonate mineral impurities to froth flotation in the presence of modifying agents, said modifying agents being alkyl phosphonic acids and hydrofluoric acid, and a collector, said collector being fatty acids; collecting the phosphate and carbonate minerals as rougher concentrate from the overflow; subjecting the phosphate and carbonate mineral concentrate to a differential desorption with an acid to remove the fatty acid from the surface of the phosphate mineral; removing the separated carbonate minerals from the overflow; and recovering the phosphate values in the underflow.
    Type: Grant
    Filed: January 16, 1984
    Date of Patent: December 4, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Shuang-shii Hsieh, James R. Lehr
  • Patent number: 4461913
    Abstract: A two-stage continuous crystallization process for production of urea phosphate by reaction of impure wet-process orthophosphoric acid (about 54 percent P.sub.2 O.sub.5) and urea with simultaneous addition of a selected acidifying agent (sulfuric acid, hydrochloric acid, or phosphoric acid) to clarified mother liquor used as recycle in the process. Addition of the acidifying agent decreases pH in the crystallization process whereby the solubility of a contaminating water-insoluble iron phosphate-urea salt [FeH.sub.3 (PO.sub.4).sub.2.2CO(NH.sub.2).sub.2 ] is increased, purity of the crystalline urea phosphate product is improved significantly, and the useful storage life of the recycle mother liquor is prolonged.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: July 24, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Harry T. Lewis, Ewell F. Dillard
  • Patent number: 4454101
    Abstract: The dewatering capabilities of sulfite sludges from flue gas desulfurization facilities are substantially improved by the addition of relatively small amounts of sodium thiosulfate additive, or additives derived from or related to sodium thiosulfate, into the scrubber slurry liquor. As an added embellishment, these predetermined amounts of said additives are greater than those required for effecting substantial scale inhibition in the scrubber innards. Subsequently, conventional dewatering of the sulfite sludge to about 80 to 90 percent solids directly produces a waste product disposable in both an economically and an environmentally acceptable manner, in that the thixotropic characteristics of such sludges which are associated therewith upwards to about 70-percent solids therein are completely eliminated.
    Type: Grant
    Filed: June 29, 1983
    Date of Patent: June 12, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Forrest C. Garrison, William L. Wells
  • Patent number: 4449480
    Abstract: A proess, and a composition of matter utilized therein, to obtain transformation of the glochidia of freshwater mussels to the juvenile stage. In nature, glochidia normally transform while as parasites on fish. The instant artificial process involves the use of cell culture and bacteriological techniques to best assure environmental integrity during the protracted culture period. The composition of the media includes a combination of the blood plasma of fish and commonly available tissue culture fluids and inorganic salts. A nonspecific component of fish blood plasma in combination with the media, supra, was determined to be essential for glochidial transformation to juveniles.
    Type: Grant
    Filed: October 29, 1982
    Date of Patent: May 22, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Billy G. Ison, Robert G. Hudson
  • Patent number: 4439223
    Abstract: Highly concentrated nitrogen suspension fertilizers which have excellent long-term storage and handling properties in both warm and severely cold weather are produced from urea, ammonium nitrate, water, and attapulgite clay and contain urea crystals suspended in a saturated solution containing urea and ammonium nitrate. The compositions must be maintained within a very narrow range to produce satisfactory suspensions. Deviation from this narrow range results in poor quality, unusable products. For prevention of scale formation and production of small crystals, the products are cooled in two or more stages with gelling-type clay added prior to or during crystallization and with air cooling used in the cooling stage(s) involving crystallization.
    Type: Grant
    Filed: April 18, 1983
    Date of Patent: March 27, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Jeffrey L. Boles, Thomas M. Jones
  • Patent number: 4435372
    Abstract: The concentration of impurities in wet-process phosphoric acid limits the usefulness of the acid for the production of fertilizers, feedgrade phosphate and detergents. The aluminum, magnesium, and fluoride impurities are removed with the calcium sulfate hemihydrate filter cake by hydrolyzing and recycling the off-gas scrubber solutions in the presence of a ferric iron catalyst. The aluminum and magnesium are reduced to less than 0.1 percent in the acid product by the precipitation of (Ca,Mg)Al.sub.2 F.sub.8 .multidot.2H.sub.2 O, which is acid insoluble and suitable for storage with the byproduct calcium sulfate. Ferric iron also serves as a catalyst for the simultaneous precipitation of (Na,K).sub.2 SiF.sub.6. Subsequent additions of potassium as, for example, in the teachings of Gilbert (U.S. Pat. No. 3,338,675), can then be applied to obtain a purified phosphoric acid product suitable for most commercial applications.
    Type: Grant
    Filed: January 17, 1983
    Date of Patent: March 6, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Alva W. Frazier, Ewell F. Dillard
  • Patent number: 4427433
    Abstract: Method for production of granular ammonium polyphosphate fertilizer in which ammonium polyphosphate melt is prepared in a simple inline reactor and distributed onto a bed of solids in a drum granulator to bind smaller fertilizer particles into granules. The desired polyphosphate content can be obtained in the granular product by adjusting the total heat input of the feed reactants to the reactor by means of energy conservation modifications to the system. Energy losses are controlled by use of a predetermined quantity of insulation so that varying amounts of the maximum theoretical heat input can be utilized to produce products of polyphosphate contents as desired.
    Type: Grant
    Filed: September 3, 1982
    Date of Patent: January 24, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Byron R. Parker, Thomas R. Stumpe
  • Patent number: 4427432
    Abstract: The process allows essentially all of the nitrogen and P.sub.2 O.sub.5 values in the treated black ammonium polyphosphate liquid to be recovered in the form of valuable clarified product. In the process, a heel of black liquid fertilizer is first clarified by a prior-art procedure using flocculants. The improvement over the prior art picks up with the byproduct tops which is then diluted with the water of formulation required to dissolve additional amounts of ammonium polyphosphate melt. This diluted liquid is filtered, the filter cake containing upwards of 99 percent of the undesirable black carbonaceous material is discarded, and the clear filtrate, which contains essentially all of the nitrogen and P.sub.2 O.sub.5 originally in the tops, is then used in lieu of the prior-art water of formulation to dissolve additional ammonium polyphosphate melt to produce more black ammonium polyphosphate liquid.
    Type: Grant
    Filed: August 12, 1982
    Date of Patent: January 24, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Horace C. Mann, Jr., Kenneth E. McGill
  • Patent number: 4424176
    Abstract: The granulation of molten material using a heat transfer process whereby solid particles are heated, dried, or cooled by a gas: Particles are repeatedly lifted and dropped as, for example, in flighted rotary drums. By forced recirculation, gas is passed through showering particles generally perpendicular to their plane of fall. Examples show gas forced to contact particles in this manner imparts an overall volumetric heat transfer coefficient to a rotary drum superior to that expected from classical literature or presently operating rotary drum heat exchangers. Disclosure teaches gas temperature adjustment between forced recirculations. Technique usage will reduce exchanger capital cost, increase energy efficiency, and reduce pollution problems. Also, prewetting of the particles in certain instances can be utilized to effect substantially increased pseudo volumetric heat transfer coefficients when cooling non-hygroscopic materials.
    Type: Grant
    Filed: September 29, 1982
    Date of Patent: January 3, 1984
    Assignee: Tennessee Valley Authority
    Inventors: Arthur R. Shirley, Jr., Frederick T. Carney, Jr.
  • Patent number: H25
    Abstract: My testing procedures have demonstrated that thiophosphoryl triamide (I) and its linear thermal polymers (II) having the structures illustrated below are highly effective inhibitors of urease activity in agricultural soil systems.
    Type: Grant
    Filed: June 17, 1985
    Date of Patent: February 4, 1986
    Assignee: Tennessee Valley Authority
    Inventor: Robert J. Radel