| 主权项 |
1. A method for treating an aqueous solution containing dissolved materials that are able to crystallize or precipitate, by crystallization of clathrates hydrates of a host molecule which crystallize at atmospheric pressure at temperatures higher than the temperature of ice crystallization, said clathrates hydrates being less dense than said aqueous solution containing dissolved materials, wherein the following steps are carried out:
a) the aqueous solution is cooled, in first cooling means, to a temperature T1 that is higher than the temperature of ice crystallization and lower than the crystallization temperature Teq of the clathrates hydrates, and this cooled aqueous solution is introduced into a thermally insulated reactor; b) a quantity of the host molecule is added into the reactor containing the cooled aqueous solution, such that the temperature T2 of the aqueous solution remains, following this addition and following the exothermic release due to the crystallization of the clathrates hydrates, lower than the temperature Teq, whereby the clathrates hydrates of the host molecule crystallize homogeneously in all of the volume of the aqueous solution by forming a suspension of clathrates hydrates crystallized in an aqueous solution concentrated in dissolved materials that may further contain crystallized or precipitated dissolved materials; c) the suspension formed during step b) is sampled in the reactor, and said suspension is sent to a decanter wherein it is separated into an aqueous solution concentrated in dissolved materials and free of clathrates hydrates, into a suspension of clathrates hydrates crystallized in the form of a sorbet in an aqueous solution concentrated in dissolved materials and free of crystallized or precipitated dissolved materials, and optionally into a supersaturated suspension containing crystallized or precipitated dissolved materials and free of clathrates hydrates in an aqueous solution concentrated in dissolved materials; d) from the decanter is withdrawn on the one hand the aqueous solution concentrated in dissolved materials and free of clathrates hydrates, and optionally on the other hand, the supersaturated suspension containing crystallized or precipitated dissolved materials and free of clathrates hydrates; e) the aqueous solution concentrated in dissolved materials and free of clathrates hydrates withdrawn in step d), is sent back in whole into the reactor after having been cooled in second cooling means that are different from the first cooling means; or else, if in the decanter there is no supersaturated suspension then a portion of the aqueous solution concentrated in dissolved materials and free of clathrates hydrates withdrawn in step d), is sent back into the reactor after having been cooled in second cooling means, and another portion of an aqueous solution concentrated in dissolved materials and free of clathrates hydrates withdrawn in step d), is recovered and/or discharged through a purge; f) the suspension of clathrates hydrates crystallized in the form of a sorbet in an aqueous solution concentrated in dissolved materials and free of crystallized or precipitated dissolved materials obtained in step c), is sent into a liquid/solid separation apparatus wherein solid clathrates hydrates are separated from the aqueous solution concentrated in dissolved materials and free of crystallized or precipitated dissolved materials which is recycled in order to form at least a portion of the aqueous solution cooled in step a); g) the solid clathrates hydrates separated in step f) are sent into a reactor for dissociating clathrates hydrates in which the clathrates hydrates are dissociated into purified water and into host molecules; h) the purified water and the host molecules obtained in step g) are separated, the purified water is recovered, and the host molecules are recycled in step b). |
