# US 2019/0169057 A1 · Methods for treating produced water to remove boron and ammonia > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0169057 A1 - Document ID: US20190169057A1 - Status: Published application - Kind: A1 - Application number: 16/274,295 - Filed: 2019-02-13 - Published: 2019-06-06 - Earliest claimed: 2013-03-15 - Assignees: Chevron U.S.A. Inc. - Applicants: Chevron U.S.A. Inc. - Inventors: Sandra HEIMEL - Web page: https://patentgrep.com/patent/US20190169057A1 ## CPC - C02F 9/00: Multistage treatment of water, waste water or sewage - B01D 61/026: {comprising multiple reverse osmosis steps} - B01D 61/149: {Multistep processes comprising different kinds of membrane processes selected from ultrafiltration or microfiltration} - B01D 61/58: Multistep processes - C02F 1/441: {by reverse osmosis} - C02F 5/06: using calcium compounds - E21B 43/35: {specially adapted for separating solids (down-hole drilling fluid separation systems E21B21/002; separating solids from drilling fluids E21B21/065)} - E21B 43/40: Separation associated with re-injection of separated materials {(E21B43/385 takes precedence)} - B01D 61/025: {Reverse osmosis; Hyperfiltration} - B01D 61/04: Feed pretreatment - B01D 2311/268: Water softening - B01D 2317/025: Permeate series - C02F 1/20: by degassing, i.e. liberation of dissolved gases (degasification of liquids in general B01D19/00; arrangement of degassing apparatus in boiler feed supply F22D) - C02F 1/24: by flotation (C02F1/465 takes precedence) - C02F 1/42: by ion-exchange (ion-exchange in general B01J) - C02F 1/442: {by nanofiltration} - C02F 1/444: {by ultrafiltration or microfiltration} - C02F 1/52: by flocculation or precipitation of suspended impurities {(C02F1/463 takes precedence)} - C02F 1/5245: {using basic salts, e.g. of aluminium and iron} - C02F 1/66: 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) - C02F 5/00: Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents (softening using ion-exchange C02F1/42) - C02F 5/025: {Hot-water softening devices} - C02F 5/083: {Mineral agents} - C02F 2001/007: {Processes including a sedimentation step} - C02F 2001/425: {using cation exchangers} - C02F 2101/10: Inorganic compounds - C02F 2101/108: {Boron compounds} - C02F 2101/16: Nitrogen compounds, e.g. ammonia - C02F 2101/32: Hydrocarbons, e.g. oil - C02F 2103/10: from quarries or from mining activities - C02F 2103/365: {from petrochemical industry (e.g. refineries)} - C02F 2209/06: pH - C02F 2209/10: Solids, e.g. total solids [TS], total suspended solids [TSS] or volatile solids [VS] - C02F 2209/11: Turbidity - C02F 2303/22: Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence) - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract Produced water from a crude oil or natural gas production process is purified using a membrane purification system for petroleum production, agricultural, commercial and domestic uses. The produced water is pretreated to remove, at least, particulates and oil from the produced water. The minimally pretreated water is then purified in a membrane purification system that is operated at conditions such that contaminants are removed. In particular, the membrane purification system is operated with pH adjustments to allow boron and ammonia to be effectively removed. In some embodiments, greater than 95% of the boron content and greater than 95% of the ammonia content are removed. Some method embodiments include no separate ion exchange separation step capable of removing ammonia. ## Claims ### Claim 1 A method of treating produced water produced from an oil or gas well, comprising: a. recovering the produced water comprising a mixture of water, oil, solid particulates and dissolved solids from a well extending into a subterranean formation; b. pretreating the produced water to remove a portion of the oil and solid particulates therefrom, to produce a clarified water having a turbidity of no more than 0.5 NTU units, an oil content of at most 5 ppm, solid particulates that are at most 5 μm in size, a boron content of greater than 25 mg/L, and an ammonia content of greater than 10 mg/L; and c. removing boron content and ammonia content from the clarified water using a first reverse osmosis membrane module and a second reverse osmosis membrane module to form purified water; wherein: the clarified water is passed through one of the first or second reverse osmosis membrane modules at a first pH from such that the boron content is reduced to less than 5% of the boron content of the clarified water; and the clarified water is passed through one of the first or second reverse osmosis membrane modules at a second pH such that the ammonia content is reduced to less than 5% the ammonia content of the clarified water. ### Claim 2 (depends on 1) The method of claim 1, wherein the first pH is from about 10.5 to about 11.5. ### Claim 3 (depends on 1) The method of claim 1, wherein the second pH is from about 3 to about 7.9. ### Claim 4 (depends on 1) The method of claim 1, wherein the first plurality of reverse osmosis membrane elements and second plurality of reverse osmosis membrane elements comprise polymeric membrane elements. ### Claim 5 (depends on 1) The method of claim 1, wherein pretreating the produced water includes filtering the produced water using microfiltration, ultrafiltration, nanofiltration and combinations thereof. ### Claim 6 (depends on 1) The method of claim 1, further comprising passing the produced water through an ultrafiltration membrane, wherein the produced water contains greater than 100,000 ppm TDS. ### Claim 7 (depends on 1) The method of claim 1, wherein pretreating the produced water comprises partially softening the produced water to a hardness in a range from 1 to 50 ppm. ### Claim 8 (depends on 1) The method of claim 1, wherein pretreating the produced water comprises partially softening the produced water at a temperature of from 150° F. to 200° F. ### Claim 9 (depends on 1) The method of claim 1, wherein pretreating the produced water comprises partially softening the produced water by passing the produced water through an ion exchange softening process for reducing the hardness of the produced water and wherein the partially softened produced water has a hardness of greater than 50 ppm. ### Claim 10 (depends on 1) The method of claim 1, wherein pretreating the produced water does not include a warm lime softening process, and further does not include an ion exchange softening process. ### Claim 11 (depends on 1) The method of claim 1, wherein pretreating the produced water includes precipitating particulates in the produced water in a clarification module, wherein precipitating particulates in the produced water includes supplying a sufficient amount of an alkaline chemical, selected from sodium hydroxide, soda ash, sodium carbonate, calcium oxide, calcium hydroxide, calcium carbonate, magnesium oxide and combinations thereof, to the produced water to increase its pH by at most 2 numbers, and further comprising filtering the pretreated water from the clarification module. ### Claim 12 (depends on 1) The method of claim 1, wherein the produced water has a TDS content of greater than 1000 mg/l. ### Claim 13 (depends on 1) The method of claim 1, wherein the clarified water has a TDS content of greater than 1000 mg/l. ### Claim 14 (depends on 1) The method of claim 1, wherein the purified water contains no more than 0.004 ppm hardness, no more than 0.1 ppm silica and no more than 19 ppm TDS. ### Claim 15 (depends on 1) The method of claim 1, wherein the ammonia content is reduced to less than 3% the ammonia content of the clarified water. ### Claim 16 (depends on 1) The method of claim 1, wherein the purified water contains no more than 0.5 mg/L boron. ### Claim 17 (depends on 1) The method of claim 1, wherein the purified water contains no more than 5 mg/L ammonia. ### Claim 18 (depends on 1) The method of claim 1, wherein the purified water contains no more than 0.79 mg/L ammonia and no more than 0.41 mg/L boron. ### Claim 19 (depends on 1) The method of claim 1, wherein a feedstream for the second reverse osmosis membrane comprises a permeate stream of the first reverse osmosis membrane module. ### Claim 20 (depends on 1) The method of claim 1, wherein a feedstream for the first reverse osmosis membrane comprises a permeate stream of the second reverse osmosis membrane module.