Low-yield single-pump two-stage reverse osmosis system

Abstract

The invention relates to a low-yield single-pump two-stage reverse osmosis system. Pretreated running water is connected with a first-stage reverse osmosis membrane through a first-stage booster pump. A concentrated water outlet pipeline of the first-stage reverse osmosis membrane is sequentially and serially connected with a first-stage pressure gauge and a first-stage waste water proportional valve. The first-stage waste water proportional valve is in parallel connection with a washing electromagnetic valve and then connected with a concentrated water outlet. A pure water outlet pipeline of the first-stage reverse osmosis membrane is sequentially and serially connected with a second-stage pressure gauge and a one-way valve A and then connected with a water inlet of a second-stage reverse osmosis membrane. Waste water of the second-stage reverse osmosis membrane flows back to a water inlet of the booster pump through a second-stage proportional valve. A second-stage pure water outlet pipeline of the second-stage reverse osmosis membrane is sequentially and serially connected with a water quality monitoring instrument and a producing water quality control valve. By employing the low-yield single-pump two-stage reverse osmosis system, producing water quality can reach standards fast, long-term stability of the producing water quality is achieved, recovery reaches at least 20%, complex pretreating processes are not needed, salt removing rate can stably reach more than 99%, and double reduction of producing cost of ultrapure water produced by using DI (desorption ionization) (ion exchange) as post-stage purification.

Description

technical field [0001] The invention relates to a small-scale water purification system, in particular to a water purification system of ≤10L / H25°C. Background technique [0002] Existing small-scale water purification systems widely use reverse osmosis technology in the primary purification stage. Considering the structural space, cost and design difficulty of small-scale systems, single-stage reverse osmosis (single-stage RO) technology is widely used at present, and the application of this technology is the same It can achieve the purpose of removing more than 90% of inorganic ions, organic matter and particles, but there are the following disadvantages: [0003] 1) When dealing with water sources with high salinity, the desalination rate of the single-stage RO system cannot guarantee a sufficient desalination rate-based on the desalination characteristics of the reverse osmosis membrane itself, the removal rate is the standard, and the salt content of the produced water ...

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Problems solved by technology

[0003] 1) When dealing with water sources with high salinity, the desalination rate of the single-stage RO system cannot guarantee a sufficient desalination rate-based on the desalination characteristics of the reverse osmosis membrane itself, the removal rate is the standard, and the salt content of the produced water will also be With the increase of the salinity of the influent water, it will increase accordingly. When a certain index is fixed, the established conductivity standard of the product water will not be reached; because the salt content (ion concentration) of the product water quality is still high, if the later stage needs to be carried out Deep purification, such as using ion exchange methods, will also directly reduce the treatment capacity and service life of ion exchange resins;

[0004] 2) The stability of the product water quality is not good - the product water quality of the single-stage reverse osmosis system is affected by many factors such as pressure, temperature and pH at the same time. Once the conditions fluctuate, the product water quality will fluctuate rapidly and it will take longer Stablize;

[0006] 1) The recovery rate is not high - because the two-stage reverse osmosis is designed to use the product water of the first-stage reverse osmosis membrane (usually the recovery rate of a single membrane is between 15-30%) as the water inlet of the second-stage reverse osmosis membrane, the This method will inevitably lead to an extremely low recycling rate of the system as a whole. For small and simple two-stage reverse osmosis systems, the overall recycling rate of the system usually does not exceed 15-20%;

[0007] 2) The durability and reliability are not high - because the small system is different from the industrial system, based on the principles of economy and practicability, the pretreatment process of the raw water is simple, the controllability of the system operating parameters is relatively low, and usually the raw water Without softening, the membrane filtration system may work in a non-ideal (or even bad) state for a long time, which may easily cause problems such as scaling, fouling, and performance degradation. Therefore, the service life is often not high, and the water quality of the produced water cannot be stable for a long time;

[0008] 3) Complex system design - some small two-stage reverse osmosis systems refer to industrial system design, resulting in very complex systems and a substantial increase in cost, so the economic benefits are not obvious. At the same time, the complexity of the system is difficult for non-professional users to operate and maintain. brought a lot of inconvenience

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