Quickly understand reverse osmosis antiscalant in one minute

What is a scale inhibitor?

        Scale inhibitor ( Scale Inhibitor ), is a type of agent that can disperse insoluble inorganic salts in water, prevent or interfere with the precipitation and scaling of insoluble inorganic salts on metal surfaces.

Mechanism of scale inhibitor

Chelation In water with medium and low hardness, the chelation of scale inhibitors plays an important role.

Dispersion In water with medium and high hardness, the dispersion function of scale inhibitors plays a major role.

Lattice distortion Prevent scaling particles from arranging themselves on their regular lattice points.

Common classification of scale inhibitors

1 Organic phosphorus series scale inhibitors

        It has good chelation, low-limit inhibition and lattice distortion effects. It can prevent the formation of scale from scaling salts in water, especially calcium carbonate scale. It is chemically stable in water and is not easily hydrolyzed. At higher concentrations in water, it has a good corrosion inhibition effect.

2 Organic phosphonate series scale inhibitors

        It is a neutral sodium salt of organic phosphorus series scale inhibitors, which can prevent the formation of scale from scaling salts in water, especially calcium carbonate scale. It is suitable for circulating cooling water in thermal power plants and refineries, and oilfield injection water systems. It also has good compatibility with other additives, especially suitable for neutral to acidic formulations, without ammonia odor producing oxides.

3 Polycarboxylic acid scale dispersants

        Non-toxic, water-soluble, can operate under alkaline and medium concentration multiples without scaling. PAAS It can disperse the microcrystals or silt of salts such as calcium carbonate and calcium sulfate in water without precipitation, thus achieving the purpose of scale inhibition.

4 Compound scale inhibitors

        It is a composite product composed of organic phosphonic acid and polycarboxylic acid polymers, which has high corrosion inhibition and scale inhibition performance, and its temperature resistance is particularly good, which can be effectively used in the internal water treatment of low-pressure boilers.

5、 RO Scale inhibitor

        Suitable for reverse osmosis systems, nanofiltration and ultrafiltration systems, it can prevent membrane scaling, improve water yield and water quality, and reduce operating costs.

How to correctly select and use reverse osmosis scale inhibitors

What are the main components of reverse osmosis scale inhibitors?

        Reverse osmosis scale inhibitors mainly include some natural dispersants, phosphonic acids, phosphonocarboxylic acids and phosphosulfonic acids and high molecular polymers, and the vast majority of scale dispersants currently used are high molecular polymers. They can disperse insoluble inorganic salts in water, prevent or interfere with the deposition and scaling of insoluble inorganic salts.

The difference between reverse osmosis scale inhibitors and circulating water scale inhibitors

        Due to the different situations they face, the requirements for the two are different:

        The operating environment of circulating water requires long-term effectiveness and antibacterial properties. A large number of polymer dispersants can be used to provide dispersion of suspended solids to increase the scale inhibition effect. The circulating water system has a large volume and is operated outdoors, so the purity requirements for the agent are not high.

        Because the reverse osmosis scale inhibitor has a short action time, it requires the scale inhibitor to react quickly with the scaling ions, so it requires fast and high efficiency; in addition, because the internal channels of the membrane are narrow, the use of polymer dispersants will cause greater problems; at the same time, the scale inhibition process is a concentration process on the membrane surface, and if the impurity content is high, it will also affect the stable operation of the system.

        A significant advantage of high concentrations of scale inhibitors is that it can reduce transportation costs.

        For single-type scale inhibitors, the higher the concentration, the narrower the stable range. For compounded scale inhibitors, due to the different stable ranges of each single agent, it is more difficult to increase the concentration of the product.

        In addition, the higher the concentration of the scale inhibitor, the faster the rate of change during storage, and the higher the impurity content.

How to calculate the dosage of reverse osmosis scale inhibitor

        The recommended concentration of reverse osmosis scale inhibitor is generally 3-6ppm That is, for every ton of water entering the reverse osmosis equipment, 1 tons of scale inhibitor need to be added. 3-6g的阻垢剂。

        Monthly usage calculation: W=Q×S×H×30/1000 Where: W is the monthly usage ( Kg );

Q is the influent flow rate of the reverse osmosis equipment ( m3/h ); S is the dosage concentration ( 3-6ppm That is, g/ ton), H is the working time of the reverse osmosis equipment (hours);

       1000 is g and Kg conversion.

        Anti-scaling agents for reverse osmosis are typically added before the security filter, i.e., the precision filter, of the reverse osmosis system (through the filter element, allowing the added anti-scaling agent to mix well with the raw water). They are added to the pipeline of the reverse osmosis equipment via a metering pump. The original solution can be used directly or diluted before use; the dilution ratio must not exceed 10 times, i.e., the concentration must not be lower than 10%。