Forward osmosis absorption liquid using and recycling method and forward osmosis absorption device

Abstract

The invention discloses a forward osmosis absorption liquid using and recycling method and a forward osmosis absorption device, and belongs to the field of water treatment. According to the forward osmosis absorption liquid using and recycling method, raw material liquid is absorbed by the absorbing liquid in a forward osmosis device, so that in a raw material liquid concentration process, the absorbing liquid is an inorganic saline water solution and comprises dissolved sodium sulfate; the concentration of sodium sulfate is greater than 20wt%, and the temperature is 35-45 DEG C; the osmosis pressure of the absorbing liquid is 110-150bar; the recycling of the absorbing liquid comprises the processes of cooling crystallization and concentration recycling. By the use of the characteristic that the sodium sulfate solution is greatly different in dissolving degree due to different temperatures, the high-concentration sodium sulfate solution is used as the absorbing liquid, so that the concentration factor of the raw material liquid is increased as much as possible; when the absorbing liquid is recycled, a cooling crystallization device is added, and the concentration of sodium sulfate is reduced; under a condition of relative low pressure, the absorbing liquid is recycled by nano filtration or/and reverse osmosis concentration, and therefore, the energy consumption is low, and the cost is low; the investment and operation cost of equipment is lowered.

Description

technical field [0001] The invention belongs to the field of water treatment, and in particular relates to a method and a device for using and recovering forward osmosis drawing liquid. Background technique [0002] In the field of water treatment, the traditional method of concentrating water and other materials is evaporation and reverse osmosis. Evaporation requires high energy consumption and high operating costs. Reverse osmosis is limited by osmotic pressure, and the concentration ratio is not easy to make high. [0003] Forward osmosis technology is a new type of membrane separation treatment technology, which does not require external pressure as the separation driving force (or can operate under a lower external pressure), but relies on the osmotic pressure difference of the solution itself to promote the forward osmosis separation process , with significant advantages such as high recovery rate and relatively light membrane fouling. [0004] Forward osmosis uses t...

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Problems solved by technology

[0005] "Study on Optimization of Operating Parameters of Forward Osmosis Membrane Bioreactor" (Liao Wenchao et al. "Water Treatment Technology", Volume 39, Issue 12, Page 24-27, December 2013) uses low-concentration sodium sulfate solution as the draw solution for forward osmosis reaction , the extraction capacity is low, it is difficult to process raw material liquids such as seawater, and there is no systematically optimized recovery process for the used extraction liquid, resulting in environmental pollution and waste of resources

[0006] "Forward osmosis-nanofiltration coupled treatment of picric water desalination process" (Shi Qiang et al. "Water Purification Technology" May 2012, Volume 31, pp. 25-28, 58) uses low-concentration divalent inorganic salts as the drawing solution. A two-stage nanofiltration system is designed for the recovery of the draw liquid. The draw effect of the draw liquid is poor, and it is difficult to concentrate the high-concentration raw material liquid at a high multiple. Moreover, the draw liquid is directly recovered by nanofiltration, and the effect is affected by the osmotic pressure. bad

[0007] The Chinese utility model patent with the publication number CN203307172U discloses a carbon source recovery and treatment device for urban sewage, which uses seawater as the drawing solution with a low concentration factor, and adopts nanofiltration, reverse osmosis, and membrane distillation when recovering the drawing solution , although the recovery and reuse of the draw liquid can be realized, but the reverse osmosis and nanofiltration are limited by the osmotic pressure, and the distillation consumes a lot of energy, and the investment and operation costs are high

[0008] After searching by the applicant and its agent, no reports of using high-temperature, high-concentration sodium sulfate aqueous solution as the drawing solution were found

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