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公开(公告)号：US20240025772A1
公开(公告)日：2024-01-25
申请号：US18266259
申请日：2021-12-24
Applicant: KURITA WATER INDUSTRIES LTD.
Inventor： Yuta OHTSUKA , Kunihiro HAYAKAWA , Gou NAKAGAWA
CPC classification number: C02F1/441 , C02F1/76 , B01D65/08 , C02F2303/20 , B01D2321/168
Abstract: The purpose of the present invention is to provide a technique whereby it becomes possible to operate for a longer period of time in an aqueous system equipped with a membrane separation apparatus. The present invention can provide a membrane separation method, the method comprising containing a combined-chlorine-based oxidizing agent to water of interest, and allowing the water of interest which contains the combined-chlorine-based oxidizing agent to pass through a membrane separation apparatus, in which the water of interest which contains the combined-chlorine-based oxidizing agent has a Free 300-second value of 0.036 mg/L-Cl2 or more wherein the Free 300-second value is a result of the measurement of a chlorine concentration after 300 seconds using a free chlorine measurement reagent.
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公开(公告)号：US20220097007A1
公开(公告)日：2022-03-31
申请号：US17421734
申请日：2020-01-27
Applicant: KURITA WATER INDUSTRIES LTD.
Inventor： Yuta OHTSUKA , Kunihiro HAYAKAWA
Abstract: Multiple chemical dosing levels of differing chemical dosages are set. When control is initiated, chemical dosing is started at the level with the highest chemical dosage. Each time a sampling period S passes, the rate of increase in the pressure difference of an RO system is compared with a threshold value A. When the rate of increase is at or below the threshold value A, the chemical dosage is reduced to the level that is one step lower. When the rate of increase is greater than the threshold value A, the chemical dosage is increased to the level that is one step higher.
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3.发明申请公开(公告)号：US20250099916A1
公开(公告)日：2025-03-27
申请号：US18715096
申请日：2022-12-08
Applicant: KURITA WATER INDUSTRIES LTD.
Inventor： Yuta OHTSUKA , Junichi TAKAHASHI , Kunihiro HAYAKAWA
Abstract: A silica fouling inhibition method for a reverse osmosis membrane system is provided, in which an acrylic acid-based polymer and/or a maleic acid-based polymer; and a combined chlorine-based oxidizing agent and/or a combined bromine-based oxidizing agent are allowed to be present in water to be treated. A silica fouling inhibitor for a reverse osmosis membrane system is provided, the silica fouling inhibitor includes: a copolymer of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid and/or a terpolymer of acrylic acid, acrylamide methylpropanesulfonic acid, and N-substituted acrylamide; and a combined chlorine-based oxidizing agent and/or a combined bromine-based oxidizing agent.
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公开(公告)号：US20250051203A1
公开(公告)日：2025-02-13
申请号：US18721662
申请日：2022-12-15
Applicant: KURITA WATER INDUSTRIES LTD.
Inventor： Yuta OHTSUKA , Chikako SHIMPO , Gou NAKAGAWA , Junichi TAKAHASHI , Kunihiro HAYAKAWA
Abstract: A method for preventing microorganism fouling in a water system containing a reducing agent, said microorganism fouling prevention method for a water system being characterized by adding a stabilized chlorine-based oxidizing agent composed of a chlorine-based oxidizing agent and a sulfamic acid compound, with the ratio of the sulfamic acid compound relative to 1 mol effective chlorine of the chlorine-based oxidizing agent being 1-1.5 mol, and/or a stabilized bromine-based oxidizing agent composed of a bromine-based oxidizing agent and a sulfamic acid compound, with the ratio of the sulfamic acid compound relative to 1 mol effective chlorine conversion amount of the bromine-based oxidizing agent being 1-1.5 mol, to the water system, such that the addition concentration of the stabilized chlorine-based oxidizing agent and/or the stabilized bromine-based oxidizing agent relative to the reducing agent concentration in the water system is 2.5 times or more by molar ratio.
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