US 5,814,224 AGranted

Method for complex processing of sea-water

AssigneesInstitut Geokhimii I Analiticheskoi Khimii IM.V.I.Vernadskogo Ran (Geokhi Ran), Aktsionernaya Kompania Po Transportu Nefti "Transneft", Aktsionernoe Osbchestvo "Nauchno-Teknicheskaya Korporatsia" Chistaya Vode, Gosudarstvennaya Akademia Nefti Gaza IM. I.M.Gubkina

InventorsRuslan Khazhsetovich Khamizov, Boris Fedorovich Myasoedov, Boris Antonovich Rudenko, Larisa Ivanovna Mironova, Evgeny Gennadievich Abramov, Olga Vladimirovna Fokina, Eduard Grigorievich Novitsky, Vladimir Pavlovich Vasilevsky, Semen Ilich Gdalin, Valery Davydovich Chernyaev, Mikhail Ekhilievich Shvarts, Alexandr Sergeevich Dzhardzhimanov, Anatoly Nikolaevich Dmitrievsky, Kaplan Saferbievich Basniev, Jury Anatolievich Rakhmanin

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Abstract

A method for complex procesing of sea-water comprises the successive steps of mechanical filtration, calcium separation on modified zeolite, magnesium separation on weak-acid cation exchanger and processing of the resulting softened sea-water, regeneration of the modified zeolite and regeneration of the weak-acid cation exchanger. During the step of processing of the softened sea-water, its desalination it carried out so as to produce fresh water and simulatneously produce secondary brine having a concentration of salts at least as high as 100 g/l whereby the modified zeolite is regenerated. A plant for implemention of the method of complex processing of sea-water comprises a filter, two sorption columns for calcium separation connected in parallel with each other, a sorption unit for magnesium separation, a softened sea-water processing unit and a mixed concentrate processing unit.

Claims24

Dependent claims

A method for processing seawater comprising the following steps:

(a) filtering the seawater by passing the seawater through mechanical filtering means for separating the seawater into a suspension and a first filtrate whereby to obtain the suspension and the first filtrate;
(b) passing the first filtrate through a zeolite in sodium form that has been treated with magnesium to enhance a selectivity of the zeolite for ion exchange of calcium and magnesium whereby to remove calcium from the filtrate so as to obtain partially softened seawater and a zeolite enriched in calcium;
(c) passing said partially softened seawater through a weak-acid cation exchanger to remove magnesium from the partially softened seawater whereby to obtain further softened seawater and a weak-acid cation exchanger enriched in magnesium;
(d) desalinating the further softened seawater to obtain fresh water and a secondary brine comprising salt in a concentration of at least 100 g/liter;
(e) passing said secondary brine through the zeolite enriched in calcium to obtain a regenerated zeolite and a mixed concentrate comprising calcium, sodium and potassium salts;
(f) passing a solution of sodium carbonate through the weak-acid cation exchanger enriched in magnesium to obtain a regenerated weak-acid cation exchanger and a resultant solution supersaturated with magnesium carbonate that settles upon standing;
(g) repeating at least steps (a) through (e) with the first filtrate being passed through the regenerated zeolite in a repeated step (b) and with the partially softened seawater being passed through the regenerated weak-acid cation exchanger in a repeated step (c).

4 more elements

Dependencies are inferred from the claim text.