information centre


Application of forward osmosis technology in brine concentration

来源:杭州天创环境科技股份有限公司 编辑:程棋波 阅读量:30465 2019-08-13 10 : 53 : 46Source : Hangzhou Tianchuang Environmental Technology Co., Ltd. Editor: Cheng Qibo

Introduction: Forward osmosis is a new membrane separation technology developed in recent years for wastewater treatment and desalination. This article mainly introduces the use of old brine as the draw solution, through forward osmosis concentration, to achieve the concentration of refined brine with low energy consumption, thereby reducing economic costs. This process mainly uses special separation membranes as the core, low operating cost and small footprint.
In general, the salt production in China's seaside is mainly made by the salt drying process. When salt is exposed, the seawater is first introduced into the evaporation pond. After the sun evaporates water to a certain extent, it is poured into the crystallization pond. When the sun continues, the seawater will become a saturated solution of salt, and then the salt will gradually precipitate.
However, the salt-making process using salt drying technology takes up a large area, has a long salt-making cycle, and is greatly affected by the weather. With the continuous increase of salt production, the area demand of salt fields is increasing. However, due to the limitation of the area where the salt is produced, the land resources around the salt field are tight, and it is impossible to expand the salt production.
Forward osmosis is a new membrane separation technology developed in recent years for wastewater treatment and desalination. Forward osmosis refers to the process by which water is transferred spontaneously from a region of high water chemical potential (or lower osmotic pressure) to a region of low water chemical potential (or higher osmotic pressure) through a semi-permeable membrane. Two different osmotic solutions of water and saline are placed on both sides of the container separated by a semi-permeable membrane. When there is no external pressure, water will spontaneously diffuse from the pure water side to the saline side through the semi-permeable membrane, so that the saline side The liquid level rises until the pressure difference between the liquid level on both sides of the membrane is equal to the osmotic pressure difference on both sides of the membrane, which is the normal osmosis process. Compared with the pressure-driven membrane separation process, the forward osmosis process does not require external pressure, and is only driven by osmotic pressure. Therefore, the energy consumption during the forward osmosis operation is small, and the membrane pollution is relatively small, and it can be operated for a long time without frequent cleaning.
Ultrafiltration + nanofiltration + forward osmosis coupling process can realize the purification and concentration of brine. Through ultrafiltration + nanofiltration process, larger pollutants in brine and divalent ions in water are removed to achieve the purification of brine. This article mainly introduces the use of old brine as the draw solution, through forward osmosis concentration, to achieve the concentration of refined brine with low energy consumption, thereby reducing economic costs. This process mainly uses special separation membranes as the core, low operating cost and small footprint.

Test device diagram
As shown in the figure above, the old brine and brine respectively circulate on both sides of the forward osmosis membrane. Using the characteristic of selective permeability of the forward osmosis membrane, the osmotic pressure difference on both sides of the membrane is used as the driving force to move water from the brine side to the Halogen side, so as to achieve the purpose of brine concentration. In the experiment, the concentration process is carried out in two steps: first, the first-stage concentration of the nanofiltration produced water (brine-0) is performed using the diluted old brine (old brine-1) as the driving liquid, and the membrane flux will gradually increase during the concentration process. Decrease, when it reaches the predetermined value, stop concentrating to obtain brine-1; then use the new old brine (old brine-0) to perform secondary concentration of brine-1 to obtain old brine-1 and final product brine-2, as shown in the figure 4 shown.

Schematic diagram of two-stage concentration process of forward osmosis
In a two-month pilot test in a salt field in Shandong Province, the following conclusions were finally obtained by optimizing the test parameters:
Using the forward osmosis concentration process, using the refined brine as the feed liquid, and concentrating with 28 ° Be '(Baume degree) old brine, when the old brine: brine (volume ratio = 1: 1), the The brine is concentrated from 5.5 ° Be 'to 16.1 ° Be', and the average energy consumption per ton of water is 4.77kW.h when the average operating flux is 8.14LMH; when the old brine: brine (volume ratio = 1.5: 1), the brine is removed from 5.5 ° Be 'is concentrated to 17.7 ° Be', with an average operating flux of 9.01LMH, the energy consumption per ton of water is 4.32kW.h; when the old brine: brine (volume ratio = 1.5: 1), the brine is changed from 5.5 ° When Be 'is concentrated to 16.4 ° Be' and the average operating flux is 10.46LMH, the energy consumption per ton of water is 3.72kW.h. The electrodialysis condenses the brine to 19%, which translates to about 200 kW.h of energy per ton of salt. Therefore, the concentration of energy is about 1/4 of that of electrodialysis using forward osmosis technology.
Taken as a whole, the use of forward osmosis technology for concentration has lower energy consumption. Moreover, no additional driving force is needed. The forward osmosis membrane has good pollution resistance and long service life, so the operating cost is low.
However, the application of forward osmosis technology to industrialization is still constrained by many factors, the key of which is the choice of forward osmosis membrane and extraction solution. In this project, the retention rate of the forward osmosis membrane is relatively low, and the ion diffusion phenomenon is serious, which results in the degradation of the feed water quality. The calcium, magnesium, and sulfate ions need to be further removed before they can be used further. Therefore, the development of a forward osmosis membrane with high rejection and large flux is the key to the industrialization of forward osmosis technology.

Related reading: Application of MBR integrated equipment in rural sewage treatment
This article is submitted by Hangzhou Tianchuang Environmental Technology Co., Ltd. and does not represent the views and positions of this site. The content of the article is for reference only. If it involves infringement, please contact this site in time to deal with it. The picture is authorized for publication and the copyright belongs to the original author.

I want to comment

Civilize the Internet and speak rationally. (You can also enter 200 characters)

All comments represent the opinions of netizens and have nothing to do with this stand.

related 3d之家

What are the total investment of 13.8 billion in 2019 over 500 million village and town sewage projects? 2020-01-15 08:42:26
China Water Network incompletely counted 9 village and town sewage projects with an investment of more than 500 million in 2019, with a total investment of 13.813 billion. These projects are mostly distributed in the southern region. The project with the largest investment amount is 4.371 billion rural sewage treatment facilities franchise projects in Jiangning District, Nanjing City, Jiangsu Province.
Help enterprises to seize the outstanding "sea" International Evaporation and Crystallization Exhibition August 26 2020-01-14 10:37:31
The twelfth Shanghai International Evaporation and Crystallization Technology Equipment Exhibition co-sponsored by China Chemical Industry Enterprise Management Association, China Chemical Machinery Power Technology Association, Guangdong Petroleum and Chemical Industry Association, Guangdong Chemical Industry Society, and Zhenwei Exhibition Co., Ltd. Held at Shanghai New International Expo Center from August 26th to August 28th.
Ranking of 4,560 sewage treatment plants in the country 2020-01-14 09:15:29
According to incomplete statistics, the number of sewage treatment plants that have been completed and operated nationwide is about 4,500, among which there are about 30 kinds of sewage treatment processes. Today we have compiled the use of various technical processes for everyone, come and find out ~

Copyright and Disclaimer: All works marked "Source: Environmental Protection Online" on this website are works by Zhejiang Xingwang Baomingtong Network Co., Ltd.-Environment Protection Online legally owns the copyright or the right to use, and may not be reproduced without the authorization of this website , Extract or use the above works in other ways. Those who have already authorized the use of works on this website shall use them within the scope of authorization and indicate "Source: Environmental Protection Online". Anyone who violates the above statement will be held responsible for related legal responsibilities.

This website reprints and notes works from other sources (non-environmental protection online) for the purpose of transmitting more information, does not mean that this website agrees with its views or is responsible for its authenticity, and does not assume direct responsibility for such works infringement And joint liability. When other media, websites or individuals reprint from this website, they must retain the first source of the works indicated on this website and bear their own legal responsibilities such as copyright.

If you are involved in the content of the work, copyright, etc., please contact this website within one week from the date of publication of the work, otherwise it is deemed to waive the relevant rights.

Don't want to miss industry 3d之家?

Download Environmental Online App

One-click filtering to subscribe

More informative

环保新闻网热门广告位招租中 资讯页热门广告位招租——列表页右侧1

Information Leaderboard


更多 Illustration says more environmentally friendly

About Us | Site Services | Member Services | Enterprise Websites | Owned Websites | Friendly Links | Browse Product Categories | Product Sitemap | Channel

Environmental Protection Online-"Internet +" Service Platform for Environmental Protection Industry

Copyright 2020gatisrael.com All Rights Reserved Legal Adviser: Lawyer Jia Ximing of Zhejiang Tianlu Law Firm

Customer Service Hotline: 0571-87209775 Purchase Hotline: 0571-87759925 Media cooperation: 0571-87759680

Customer Service Department: Purchasing Department: Editorial Department: Exhibition cooperation: Market Group: Market Group II:

shut down
$ VoteIsLock