Systems and methods for treatment of water, such as oilfield wastewater, via chemical coagulation

Patent metadata

Field	Value
Publication number	US-2021147265-A1
Application number	US-202017062472-A
Country	US
Kind code	A1
Filing date	Oct 2, 2020
Priority date	Sep 8, 2015
Publication date	May 20, 2021
Grant date	—

Abstract

Described herein are systems and methods for treating an aqueous input stream comprising at least one suspended and/or emulsified immiscible phase (e.g., oil, grease) and, in some cases, one or more additional contaminants, such as solubilized bicarbonate (HCO3−) ions, solubilized divalent cations (e.g., Ca2+, Mg2+), solubilized trivalent cations (e.g., Fe3+, Al3+), organic material (e.g., humic acid, fulvic acid), hydrogen sulfide (H2S), and/or suspended solids. According to certain embodiments, the aqueous feed stream is supplied to a water treatment system comprising a chemical coagulation apparatus and a suspended solids removal apparatus (e.g., a clarifier). Within the chemical coagulation apparatus, an amount of an inorganic coagulant (e.g., aluminum chlorohydrate, polyaluminum chloride), an amount of a strong base (e.g., sodium hydroxide), and an amount of a polyelectrolyte (e.g., polyacrylamide) may be added to the aqueous input stream to form a chemically-treated stream. In some embodiments, the inorganic coagulant, strong base, and/or polyelectrolyte may induce coagulation and/or flocculation of at least a portion of the contaminants within the aqueous input stream, and the chemically-treated stream may comprise a plurality of flocs (i.e., particle agglomerates). In some embodiments, the chemically-treated stream is directed to flow to the suspended solids removal apparatus. Within the suspended solids removal apparatus, a plurality of flocs may be removed from the chemically-treated stream to form a contaminant-diminished stream having a lower concentration of contaminants than the aqueous input stream. In some embodiments, the chemically-treated stream and the contaminant-diminished stream each have a pH of about 8 or less. In some embodiments, the chemically-treated stream and the contaminant-diminished stream each have a temperature of about 15° C. or less.

First claim

What is claimed is:

1 - 50 . (canceled)

51 . A method for treating water, comprising:
adding an amount of an inorganic coagulant, an amount of a strong base, and an amount of a polyelectrolyte comprising polyacrylamide to an aqueous input stream comprising at least one suspended and/or emulsified immiscible phase to form a chemically-treated stream; and removing at least a portion of suspended solids from the chemically-treated stream to form a contaminant-diminished stream, wherein each of the chemically-treated stream and the contaminant-diminished stream has a temperature of 15° C. or less.

52 . The method of claim 51 , wherein the inorganic coagulant is a cationic inorganic polymer.

53 . The method of claim 51 , wherein the inorganic coagulant has a basicity of at least 50%.

54 . The method of claim 51 , wherein the inorganic coagulant has a number average molecular weight from 200 g/mol to 800 g/mol.

55 . The method of claim 51 , wherein the inorganic coagulant comprises aluminum.

56 . The method of claim 51 , wherein the polyelectrolyte is anionic or nonionic.

57 . The method of claim 51 , wherein the polyelectrolyte has a molecular weight in the range of 10,000 g/mol to 30,000,000 g/mol.

58 . The method of claim 51 , wherein the polyelectrolyte comprises anionic polyacrylamide.

59 . The method of claim 51 , wherein the removing at least the portion of suspended solids comprises gravity-based settling.

60 . The method of claim 51 , wherein the removing at least the portion of the suspended solids produces 0.25 kg or less of a solids-containing stream per barrel produced of the contaminant-diminished stream.

61 . The method of claim 51 , further comprising flowing a solids-containing stream to a solids-handling apparatus, wherein the solids-handling apparatus comprises a filter press, a vacuum filter, and/or a centrifuge.

62 . The method of claim 51 , further comprising removing at least a portion of the water from at least a portion of the contaminant-diminished stream.

63 . The method of claim 62 , wherein the removing at least the portion of the water is performed in a humidification-dehumidification desalination system.

64 . The method of claim 51 , wherein the aqueous input stream has a total suspended solids concentration of at least 500 mg/L.

65 . The method of claim 51 , wherein the aqueous input stream comprises humic acid and/or fulvic acid.

66 . The method of claim 51 , wherein the aqueous input stream has a Pt—Co color value of at least 500.

67 . The method of claim 51 , wherein a total suspended solids concentration within the contaminant-diminished stream is at least 50% less than a total suspended solids concentration within the aqueous input stream.

68 . The method of claim 51 , wherein the contaminant-diminished stream has a Pt—Co color value of 50 or less.

69 . The method of claim 51 , wherein the adding is performed in a vessel, and the residence time of the aqueous input stream in the vessel is 1 hour or less.

70 . The method of claim 51 , wherein the adding results in the precipitation of Ca 2+ ions and/or Mg 2+ ions.

71 . The method of claim 51 , wherein the adding results in the precipitation of Ca 2+ ions.

72 . The method of claim 70 , wherein the adding results in the precipitation of Ca 2+ ions and Mg 2+ ions.

73 . The method of claim 51 , wherein, during the adding, ions of the strong base interact with Ca 2+ ions to form Ca(OH) 2.

74 . The method of claim 51 , wherein each of the chemically-treated stream and the contaminant-diminished stream has a temperature of at least −5° C. and less than or equal to 15° C.

75 . The method of claim 51 , wherein the removing at least the portion of suspended solids is performed at least in part via a lamella clarifier.

Assignees

• Gradiant Corp

Inventors

• Andrews Jonn-Ross
• Govindan Prakash Narayan
• St John Maximus G
• Lam Steven

Classifications

• C02F2103/365

  from petrochemical industry (e.g. refineries) · CPC title

• C02F2103/06

  Contaminated groundwater or leachate · CPC title

• C02F1/66

  by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58) · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title

• C02F1/5236

  using inorganic agents · CPC title