Method for the purification of a liquid by membrane distillation, in particular for the production of desalinated water from seawater or brackish water or process water
US6716355B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2002 |
| Grant date | Apr 6, 2004 |
| Priority date | — |
| Expiry date | Mar 13, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A20/131
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The following process steps are carried out in order to purify a liquid by membrane distillation, in particular to produce desalinated water from seawater or brackish water or process water:passing a relatively warn vaporising stream of liquid (retentate stream) over a porous membrane, vapour flowing via the pores of the membrane to the other side of said membrane, andcondensing said vapour on a relatively cool condenser surface to give a distillate stream, said condenser surface forming the non-porous separation between a feed stream to be purified and said distillate steam, which feed stream is in counter-current with the retentate stream so that an appreciable proportion of the latent heat will be transferred via vapour to the feed stream, and a gas gap with a width of less than 5 mm being present between the porous membrane and the condenser surface.In order to improve the distillate flow rate per unit driving force, a pressure which is lower than the atmospheric pressure and higher than the vapor pressure of the feed stream is maintained in the gas gap, the porosity &egr; of the porous membrane is higher than 0.7, porosity being understood to be the ratio of the open volume to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.