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US 12,729,139 B2Granted
Treating produced water for beneficial reuse
AssigneeRenovo Resources LLC
InventorsBrad Biagini, Lnsp Nagghappan
Life of this patent
Estimating the term…
Abstract
Produced water is pre-treated to remove oil and solids. After pre-treatment, the produced water is distilled to produce a brine and a distillate. The distillate is processed to reduce a concentration of ammonia and a concentration of volatile organics present in the distillate. The treated water can, for example, be used as irrigation and agricultural water, aquifer replenishment, industrial use, freshwater for supporting oil and gas operations, or any combinations of these.
Claims20
A method of treating produced water comprising suspended solids, free oil, iron, hydrogen sulfide, dissolved salts, ammonia and volatile organics, the method comprising:
- the pre-treating the produced water, wherein pre-treating the produced water comprises:
- receiving the produced water from a storage tank and injecting an oxidant into the produced water for oxidation of the iron and the hydrogen sulfide;
- after the addition of the oxidant, directing the produced water into a solids-liquid separator, wherein reagents are added to the solids-liquid separator to aid in coagulation, flocculation, and pH adjustment to a range between about 7.0 to about 8.0 for optimizing iron oxidation, and dissolved gas is introduced to facilitate the separation of suspended oil and solid particles from the produced water;
- directing the oil and solids that are separated from the produced water in the solids-liquid separator to a solids-liquid separation process, in which thickening and dewatering occurs to generate a solid waste suitable for disposal;
- and
- recycling a filtrate from the solids-liquid dewatering process to the storage tank upstream of the pre-treatment process;
- after the pre-treating the produced water, directing the produced water to a forced circulation thermal evaporation process with external heat exchange and concentrating the produced water in an evaporator of the forced circulation thermal evaporation process to produce a brine and a distillate comprising at least a portion of the ammonia and the volatile organics;
- operating the forced circulation thermal evaporation process independent of a phase change on a heat transfer surface of an external plate heat exchanger of the evaporator, while the heated produced water remains in a liquid phase until the heated produced water flashes in a separator vessel, at which point evaporation occurs;
- after thermal evaporation by the forced circulation thermal evaporation process, reducing a concentration of ammonia in the distillate by biological nitrification and denitrification followed by solids-liquid separation, or by ion exchange to form an effluent having a reduced concentration of ammonia in comparison to the distillate;
- after ammonia reduction, subjecting the effluent to an advanced oxidation process comprising addition of the oxidant to reduce a concentration of volatile organics;
- and
- subjecting the effluent from the advanced oxidation process to pH adjustment to generate a treated water for beneficial reuse.
9 more elements
A method of treating produced water comprising suspended solids, free oil, dissolved solids, ammonia, and volatile organics, the method comprising:
- the pre-treating the produced water, wherein pre-treating the produced water comprises:
- adding an oxidant to the produced water to oxidize iron and hydrogen sulfide;
- removing the oxidized iron and hydrogen sulfide from the produced water along with the suspended solids and oil to produce a pretreatment effluent stream comprising the dissolved solids, ammonia and volatile organics;
- after removing the iron, hydrogen sulfide, suspended solids and oil from the produced water, adjusting a pH of the pretreatment effluent stream upstream of a forced circulation thermal evaporation process to maintain a brine pH between about 4.3 and about 6.5 in the forced circulation thermal evaporation process;
- and
- after pH adjusting the pretreatment effluent stream, directing the pretreatment effluent stream to the forced circulation thermal evaporation process with external heat exchange and concentrating the pretreatment effluent stream in an evaporator of the thermal evaporation process to produce a brine and a vapor that is condensed to form a distillate comprising at least a portion of unionized ammonia and volatile organics, wherein the brine comprises ionized ammonium;
- after thermal evaporation, reducing a concentration of ammonia in the distillate by biological nitrification and denitrification, followed by solids-liquid separation or by ion exchange to form an effluent having a reduced concentration of ammonia in comparison to the distillate;
- after ammonia reduction, subjecting the effluent to an advanced oxidation process to reduce a concentration of volatile organics;
- and
- subjecting the effluent from the advanced oxidation process to pH adjustment to generate a treated water.
7 more elements
A method of treating produced water from a subterranean formation to generate a freshwater for beneficial reuse, the method comprising:
- pre-treating the produced water, wherein the pre-treating the produced water comprises:
- oxidizing at least a portion of the produced water;
- and
- after oxidizing at least the portion of the produced water, separating a waste stream from the produced water to generate a pretreatment effluent stream, wherein the waste stream comprises a first portion of solids from the produced water and the oxidized portion of the produced water, wherein the pretreatment effluent stream comprises dissolved solids, ammonia, and volatile organics;
- evaporating at least a portion of the pretreatment effluent stream to generate a brine and a vapor, wherein the brine comprises ionized ammonium, wherein the vapor comprises nonionized ammonia, wherein at least the portion of the pretreatment effluent stream is evaporated while maintaining a brine pH between about 4.3 and about 6.5;
- condensing the vapor to generate a distillate stream;
- and
- post-treating the distillate stream, wherein the post-treating the distillate stream comprises reducing a concentration of ammonia and a concentration of volatile organics in the distillate stream to generate the freshwater.
5 more elements
Dependencies are inferred from the claim text.