# US 11,897,801 B2 · Silica scale inhibitors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,897,801 B2 - Document ID: US11897801B2 - Status: Granted - Kind: B2 - Application number: 16/940,498 - Filed: 2020-07-28 - Published: 2021-02-04 - Granted: 2024-02-13 - Earliest claimed: 2019-07-30 - Assignees: Solenis Technologies, L.P. - Applicants: Solenis Technologies, L.P. - Inventors: Michael A. Todd - Web page: https://patentgrep.com/patent/US11897801B2 ## CPC - C02F 5/12: containing nitrogen (C02F5/14 takes precedence) - C08L 71/02: Polyalkylene oxides - C02F 1/00: Treatment of water, waste water, or sewage (C02F3/00 - C02F9/00 take precedence) - C02F 2103/023: {Water in cooling circuits} - C02F 2103/10: from quarries or from mining activities - C02F 2103/18: from the purification of gaseous effluents - C02F 2103/28: from the paper or cellulose industry - C02F 2103/365: {from petrochemical industry (e.g. refineries)} - Y02E 10/10: Geothermal energy - 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) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Industrial water such as in a geothermal unit is stabilized against silica polymerization and flocculation by using a combination of inhibitors including a nonionic polyether and a monomeric polycarboxylate. ## Claims ### Claim 1 A method of inhibiting the formation of silica scale in a geothermal system, comprising treating the water in the geothermal system with an anti-scalant effective amount of a combination of two inhibitors comprising a first inhibitor and a second inhibitor, wherein the first inhibitor comprises polyethylene glycol having a minimum molecular weight of 2000 g/mol and wherein the second inhibitor comprises EDTA or pentetic acid. ### Claim 2 (depends on 1) The method according to claim 1, wherein the second inhibitor comprises EDTA. ### Claim 3 (depends on 2) The method according to claim 2, wherein a combination of two inhibitors has a polyethylene glycol to EDTA weight ratio of 1:2. ### Claim 4 (depends on 1) The method according to claim 1, wherein the first inhibitor comprises PEG 9000. ### Claim 5 (depends on 1) The method according to claim 1, wherein treating the water comprises forming treated water, and wherein a concentration of the first inhibitor in the treated water is from about 0.1 ppm to about 100 ppm, and a concentration of the second inhibitor in the treated water is from about 0.1 ppm to about 100 ppm. ### Claim 6 (depends on 1) The method according to claim 1, wherein the pH is 7 to 8. ### Claim 7 (depends on 1) The method according to claim 1, wherein the first inhibitor has a weight average molecular weight of 3800 to 20000 Dalton. ### Claim 8 (depends on 1) The method according to claim 1, wherein the second inhibitor is pentetic acid. ### Claim 9 (depends on 1) The method according to claim 1, wherein the water in the geothermal system comprises 20 ppm to 1000 ppm silica as SiO2. ### Claim 10 (depends on 1) The method according to claim 1, wherein the polyethylene glycol has a weight average molecular weight of at least 4000 Dalton. ### Claim 11 (depends on 1) The method according to claim 1, wherein the polyethylene glycol has a weight average molecular weight of at least 5000 Dalton. ### Claim 12 A method of inhibiting the formation of silica scale in the water of a geothermal system, comprising treating the water of the geothermal system with an anti-scalant effective amount of a combination of two inhibitors consisting of a first inhibitor and a second inhibitor, wherein the first inhibitor comprises a polyethylene glycol having a molecular weight of at least 2000 g/mol and the second inhibitor comprises EDTA, pentetic acid, or salts thereof. ### Claim 13 (depends on 12) The method according to claim 12, wherein the water in the geothermal system comprises 1 ppm or more of Al3+. ### Claim 14 (depends on 12) The method according to claim 12, wherein the water in the geothermal system comprises 20 ppm to 1000 ppm silica as SiO2. ### Claim 15 (depends on 12) The method according to claim 12, wherein the first inhibitor comprises polyethylene glycol with a number average molecular weight of at least 3800 g/mol. ### Claim 16 (depends on 12) The method according to claim 12, wherein the first inhibitor comprises polyethylene glycol with a number average molecular weight of at least 4000 g/mol. ### Claim 17 An aqueous composition stabilized against silica polymerization and flocculation comprising water and silica, and further comprising stabilizing amounts of a first inhibitor comprising a polyethylene glycol having a molecular weight of at least 4000 g/mol and of a second inhibitor comprising EDTA or pentetic acid. ### Claim 18 (depends on 17) The aqueous composition according to claim 17, further comprising 1 ppm or more of Al+3. ### Claim 19 (depends on 18) The composition according to claim 18, comprising 0.1 to 100 pm of the polyethylene glycol and 0.1 to 100 ppm of EDTA. ### Claim 20 (depends on 17) The composition according to claim 17, comprising 200 ppm to 1000 ppm of SiO2.