Hydrate-based desalination with hydrate-elevating density-driven circulation

Abstract

In hydrate-based desalination or other water purification conducted using naturally buoyant or trapped-gas-assisted buoyancy hydrate in a hydrate fractionation column, a portion of fresh or purified product water is extracted from an upper, hydrate dissociation region of the fractionation column and reintroduced into a lower portion of the fractionation column at a point above but generally near a product water / saline water interface. The difference in density between the reintroduced product water and the fluid in the hydrate fractionation column above the point of reintroduction (water, hydrate, and gas) drives a natural circulation system which enhances the rate at which hydrate rises into the hydrate dissociation region.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10 / 266,258 filed Oct. 8, 2002, which is a divisional of U.S. patent application Ser. No. 09 / 397,500 filed Sep. 17, 1999 (now issued as U.S. Pat. No. 6,497,794 on Dec. 24, 2002), which is a continuation-in-part of U.S. patent application Ser. No. 09 / 375,410 filed Aug. 17, 1999 (now issued as U.S. Pat. No. 6,531,034 on Mar. 11, 2003), which is a continuation-in-part of U.S. patent application Ser. No. 09 / 350,906 filed on Jul. 12, 1999 (now issued as U.S. Pat. No. 6,565,715 on May 20, 2003), the entire contents of all four of which are incorporated by reference. Priority is claimed from each of those four applications. [0002] This application is also a continuation-in-part of co-pending U.S. patent application Ser. No. 09 / 941,545 filed Aug. 30, 2001, which is based on now-expired provisional U.S. Patent Application Ser. Nos. 60 / 230,790 filed Sep. 7, 2...

AI Technical Summary

Benefits of technology

"The invention is a method for conducting hydrate-based desalination or water purification in a hydrate fractionation column. The method involves introducing hydrate-forming substance into the column and allowing the hydrate to rise naturally through the column. The hydrate is then dissociated to release fresh or purified water and the hydrate-forming substance. The released water is reintroduced into the column at a lower region, where it mixes with the hydrate and flows upward through the column. This circulation pattern enhances the rate at which the hydrate rises, improving the yield of fresh water and minimizing the mixing of residual brine. The use of smaller hydrate masses also reduces the required residence time and improves heat dissipation. The invention helps prevent seawater and residual brines from being drawn upward with the hydrate as it rises, resulting in better desalination efficiency."

Problems solved by technology

As the hydrate rises, it becomes unstable and disassociates into pure water and the hydrate-forming gas or gas mixture.

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