How to choose antiscalant chemical in RO water treatment
Source: | Author:demihind | Publish time: 2021-01-02 | 116 Views | Share:
How to choose antiscalant chemical in RO water treatment?What is antiscalant dosing and antiscalant chemical price

How to choose antiscalant chemical in RO water treatment

 

Generally speaking, in the operation process of reverse osmosis system, we need to add reverse osmosis antiscalant chemical to ensure the safe and stable operation of the system.

So,how to choose antiscalant chemical in RO water treatment?

 

1. Why should anti scale be added to reverse osmosis system

In reverse osmosis (RO) system, there is an important component, that is reverse osmosis (RO) membrane. When the reverse osmosis (RO) system runs continuously, some ions (such as calcium ion, magnesium ion, etc.) in the water will continuously precipitate, and then adhere to the reverse osmosis membrane to form scale and block the membrane pore. The consequence of this is to damage the reverse osmosis membrane, and then affect the effluent efficiency of the reverse osmosis system.

If we add a antiscalant dosing system and a certain amount of anti scale chemical in the reverse osmosis process, this problem will be effectively solved.

 

2. Principle of antiscalant chemical 

Anti scale chemical can be divided into three types to prevent scaling


A) Complexation and solubilization:

After dissolving in water, the reverse osmosis scale inhibitor ionizes to form a negatively charged molecular chain, and forms a water-soluble complex or chelate with easily scaling ions (such as calcium and magnesium ions) in water, so as to increase the solubility of inorganic salts and play a role in scale inhibition.

 

B) Lattice distortion:

In reverse osmosis antiscalant chemical molecule, some functional groups occupy a certain position in the inorganic salt crystal nucleus or microcrystalline, hinder and destroy the normal production of inorganic salt crystal, slow down the growth rate of crystal, reduce the formation of salt scale.

 

C) Electrostatic repulsion force:

The reverse osmosis antiscalant is adsorbed on the microcrystal of inorganic salt after being dissolved in water, which increases the repulsion force between particles, hinders their condensation, maintains a good dispersion state, and reduces scaling.

 

3. Types of reverse osmosis (RO) antiscalant chemical

In order to choose the right reverse osmosis anti scale chemical, we need to know the different types of antiscalant.

 

A) According to the brand of RO antiscalant chemical

At present, there are mainly the following brands of antiscalant in the market.

 

· Suez RO antiscalant 

The original Ge RO antiscalant (GE water treatment was acquired by Suez in 2017)

· Nalco antiscalant

· BWA antiscalant

· Demih antiscalant

 

B) According to the main components of antiscalant chemical

Common antiscalant are mainly made of organic phosphonate, organic compounds containing phosphorus and low molecular carboxylate.


· Organic phosphonate antiscalant

For example, ATMP, HEDP, PBTCA, etc.


· Organic compounds containing phosphorus

For example, ATP, HEDP, PBTC, etc. The antiscalant containing phosphorus is easy to hydrolyze and eventually become phosphate ion, which will cause calcium phosphate scaling and water eutrophication pollution.

 

· Low molecular carboxylate 

In recent years, for the purpose of environmental protection, phosphorus free scale inhibitors are more and more popular. Acrylic acid, methacrylic acid, maleic acid, fumaric acid and other carboxyl low molecular organic compounds are widely used.


In addition to the above components of antiscalant chemical, there are polyphosphate and other types.

 

C) According to different water quality requirements

The selection and dosing of antiscalant, formally speaking, depends on the different water quality to be treated.

In the practical application of reverse osmosis system, the source of influent and water quality can not be the same. Some of the inflow is groundwater, some is tap water. Some contain more iron, some contain more colloid.

According to different water quality, antiscalant chemical can be divided into the following categories:

 

 · RO  antiscalant DhroaPro 100                    · RO  antiscalant DhroaPro 8X

 · RO antiscalant DhroaPro 220       · RO antiscalant DhroaPro 60FE

 · RO antiscalant DhroaPro 11X                     · RO antiscalant DhroaPro 191

 · RO antiscalant DhroaPro 150


 

4. Dosing of reverse osmosis antiscalant

The addition of reverse osmosis antiscalant needs a antiscalant dosing box, generally before the security filter, and the dosing amount is generally controlled at 2-6ppm. The antiscalant of the finished product generally needs to be diluted, and the best dilution ratio is no more than 10 times.

Before adding and selecting reverse osmosis antiscalant chemical, the compatibility of antiscalant and reverse osmosis membrane must be confirmed. Incompatible antiscalant can cause irreversible membrane damage.