Patents Assigned to Tetra Technologies, Inc.
  • Patent number: 5917110
    Abstract: Free-flowing moisture resistant calcium-containing particles that inhibit the water absorption characteristics of calcium products, including soluble calcium products that are hygroscopic and deliquescent, by providing a moisture resistant coating. The core of the particle is a calcium-containing material, more particularly a soluble calcium-containing material. Moisture resistant or hydrophobic coatings are applied to the core to inhibit water absorption by the calcium-containing material. The coated particles may then be more easily shipped, stored and handled as a dry, anhydrous product. A core comprised of calcium chloride coated with urea is useful as both a soil conditioner and a fertilizer. Additional plant nutrients are mixed with either the core or the coating materials to improve fertilizing qualities. Additional coatings of hydrophobic materials such as a paraffinic hydrocarbon or a polymeric resin increase the water resistance of the particles.
    Type: Grant
    Filed: October 18, 1996
    Date of Patent: June 29, 1999
    Assignee: Tetra Technologies, Inc.
    Inventor: Roger N. Kust
  • Patent number: 5907908
    Abstract: A dehumidifying pouch comprising a container having a moisture-absorption compartment and a collection compartment, the moisture-absorption compartment comprising semi-permeable material that encloses a deliquescent desiccant material and an optional deodorizing material. The collection compartment comprises walls made of a moisture impervious material. The collection compartment is connected to the moisture-absorption compartment, preferably by a broken seal, so that liquids from the moisture-absorption compartment can be transferred to the collection compartment of the pouch. The semi-permeable material can comprise polyethylene or expanded polytetrafluoroethylene, individually or a combination thereof. The moisture impervious compartment can comprise either polyethylene film or polypropylene film. Alternatively, the dehumidifying pouch is comprised of one compartment having a moisture-absorption section and a moisture collection section.
    Type: Grant
    Filed: October 1, 1997
    Date of Patent: June 1, 1999
    Assignee: Tetra Technologies, Inc.
    Inventors: Joaquin Paz Cunanan, David Prince Heaner, David J. Hanlon
  • Patent number: 5891225
    Abstract: A method for applying halide brine to surfaces requiring protection against freeze conditions, inhibition of snow and ice accumulating, deicing or freeze retardation, for example, or dust control with limited corrosion is disclosed, the method comprising the steps of forming an admixture of polyhydroxy carboxylate and polyalkoxylated amine dispersed in an halide brine solution in an amount effective to inhibit corrosion; and applying the admixture to surfaces. The method of this invention can be used to limit corrosion in the application of a halide brine to surfaces of dust-producing materials as well as surfaces requiring protection against freeze conditions.
    Type: Grant
    Filed: January 23, 1998
    Date of Patent: April 6, 1999
    Assignee: Tetra Technologies Inc
    Inventors: Surendra K. Mishra, David J. Hanlon, Nam-Sook Bae
  • Patent number: 5776344
    Abstract: A process and apparatus for treating wastewater containing nitrogen compounds is disclosed. The process includes passing the wastewater to be treated through a biologically active material in one direction to treat the wastewater and passing the treated wastewater through the biologically active material in a second direction to further treat the wastewater under alternating aerobic and anoxic conditions, converting nitrogen compounds to nitrates and nitrites, and converting nitrates and nitrites to gaseous nitrogen.
    Type: Grant
    Filed: October 26, 1995
    Date of Patent: July 7, 1998
    Assignee: Tetra Technologies Inc.
    Inventors: Donald J. McCarty, Keith Dobie
  • Patent number: 5612293
    Abstract: There is provided a method of drilling an oil or gas well, comprising drilling a wellbore into an underground formation in which a drill bit at the lower end of a drill pipe is placed at the bottom of the wellbore; pumping a first drilling fluid into the wellbore; determining the producing zone of the underground formation; and introducing a second drilling fluid into the wellbore through the drill pipe when the borehole is within the producing zone of the underground formation, wherein the second drilling fluid is a high density drill-in fluid, having a composition different from that of the first drilling fluid and including a brine system with at least one dissolved monovalent salt and at least one dissolved divalent salt together with a suspension polymer, said drilling fluid having a density of at least about 1.50 g/cm.sup.3 and a plastic viscosity of less than about 50 lbs/100 ft.sup.2.
    Type: Grant
    Filed: December 22, 1994
    Date of Patent: March 18, 1997
    Assignee: Tetra Technologies, Inc.
    Inventors: Rosa T. Swartwout, Stephen Stroh
  • Patent number: 5496472
    Abstract: This invention relates to a method and apparatus of denitrification. The apparatus includes a weir block, a denitrification vessel having a wall surface, and filter media having microorganisms on their surfaces. The weir block may have a convex outer surface which is tangentially adjacent to and preferably contiguous with the upper end of the wall, whose lower end is in contact with the water in the denitrification vessel. The method may include passing the wastewater over the convex surface of the weir block, passing the water over the second surface of the substantially vertical wall and into the denitrification vessel while preferably maintaining substantially laminar flow and limiting the dissolved oxygen in the denitrification vessel, preferably to below about 5 mg/L and more preferably to below about 4 mg/L.
    Type: Grant
    Filed: December 20, 1993
    Date of Patent: March 5, 1996
    Assignee: Tetra Technologies, Inc.
    Inventors: David C. Slack, Gregory A. Ellard
  • Patent number: 5403495
    Abstract: A method for removing dissolved fluoride from waste water involving a multiple stage process which includes a first step of contacting a solution comprising calcium fluoride with a calcium ion source to form a first precipitate and a second step of contacting the first precipitate comprising the calcium ion source with the fluoride-containing waste water solution to form a second precipitate. A first portion of the solution that has been treated directly with the waste water and which contains the second precipitate, is preferably recycled, along with calcium fluoride, to the first step for contact with the calcium ion source. A second portion of the solution treated with the waste water may be transported to a thickener or gravity settling step, and/or to a solids-dewatering step wherein standard filtration equipment may be used to produce a filter cake having a controlled particle size distribution.
    Type: Grant
    Filed: October 14, 1993
    Date of Patent: April 4, 1995
    Assignee: Tetra Technologies, Inc.
    Inventors: Roger N. Kust, Surendra K. Mishra, James B. Pfeiffer
  • Patent number: 5290531
    Abstract: A method of converting sodium bromide brine to ammonium bromide brine and optionally to calcium bromide is disclosed. The method involves introducing ammonia and carbon dioxide into the reactant brine, removing a resulting bicarbonate precipitate, driving off any excess ammonium carbonate, and optionally contacting with lime.
    Type: Grant
    Filed: March 18, 1992
    Date of Patent: March 1, 1994
    Assignee: Tetra Technologies, Inc.
    Inventors: Russell A. Fisher, Surendra K. Mishra, Rosa T. Swartwout
  • Patent number: 5277822
    Abstract: A process for the removal of thermally-stable contaminants from stack gas scrubbing amines using a continuous countercurrent ion exchange column. Amines contaminated after use in stack gas scrubbing are fed into the column containing an anion exchanger resin where the contaminants are sorbed on the resin. The amine is washed from the resin with hot water and is removed from the column. The resin is then pulsed to move the resin with the sorbed contaminants into a elution section of the column. The contaminants are removed using an eluant of sodium hydroxide solution, preferably containing chlorine to enhance elution of thiocyanate ion. A water wash removes traces of the hydroxide solution and any reaction products, and then the resin is again pulsed so as to be moved for reuse. The amines are regenerated with only the single type resin (preferably Type I) and with significantly reduced quantity of reagents.
    Type: Grant
    Filed: May 22, 1992
    Date of Patent: January 11, 1994
    Assignee: Tetra Technologies, Inc.
    Inventor: Irwin R. Higgins
  • Patent number: 5039428
    Abstract: An improved process for removing dissolved metals from waste water using a recycle high density sludge is described. Specifically, the process comprises the steps of: (1) treating waste water containing dissolved metals with a recycle stream containing alkaline surface active recycle particles to precipitate the dissolved metals on the surface of the recycle particles; (2) treating a portion of the treated waste water containing metal precipitate solids with an alkaline reagent to form alkaline surface active recycle particles; (3) recycling the alkaline treated stream containing the alkaline surface active particles; and (4) separating the portion of the stream from step (1) not treated with alkaline reagent into a water component which is free of dissolved metals and solids and a sludge component which contains solids.
    Type: Grant
    Filed: March 5, 1990
    Date of Patent: August 13, 1991
    Assignee: Tetra Technologies, Inc.
    Inventors: Thomas H. Wentzler, Surendra K. Mishra, Roger N. Kust, E. Stuart Savage
  • Patent number: 5006239
    Abstract: A novel apparatus removes hydrophobic oil from solid particulates in oily sludge waste such as waste material from oil refineries, drilling fluids or muds brines, and other chemical wastes which have solid particulates contaminated with oil. The process involves separation of different components of the sludge on the basis of their size, density and physio-chemical differences. Coarse particulates are removed with the use of screening systems such as sieve bends or vibro-sieves. Oil is removed from these coarse particulates with water rinsing. Oil is removed from fine particles by gravity separation, which separates the sludge into high and low density fractions. Froth flotation is used to remove hydrophilic materials from the high density fraction.
    Type: Grant
    Filed: April 23, 1990
    Date of Patent: April 9, 1991
    Assignee: Tetra Technologies, Inc.
    Inventor: Surendra K. Mishra