Dosage of reverse osmosis scale inhibitor and scale inhibitor clogging

This post was last edited by CoCo070563 on 2015-8-11 08:01. It depends on the flow rate of the pipeline through which the chemical is added; generally, 3-5 ppm of scale inhibitor is sufficient. Feel free to consult me for more details – contact me via private message.

Those that produce concentrated solutions are just gimmicks, and they become unstable when diluted. Stop struggling. Change the medication quickly.

The concentrates are all fake; they’re meant to deceive people, and they’re also sold at high prices. Generally, we use standard solutions, with a dosage of 2–5 g/m3. The dosage you’re using is too high; based on the maximum allowable levels, 1.1/2/4.5 = 122 g/m3. Such a high dosage can cause fouling and scaling of the membranes

What does the 2 in your calculation formula mean? Does it mean a concentration of 0.5? What is the concentration of the standard solution?

I’m not sure either whether the scale inhibitor I bought is a standard solution or a concentrated one; it was said that it needs to be diluted eight times. Could you tell me about the concentrations of these two types of solutions?

I’m not quite sure what the concentrations of the standard solution and the concentrated solution are respectively. Could you explain that?

It’s either Qingli or PWT; concentrated solutions are just a gimmick. Why do they say that? They produce concentrated solutions whose price per ton is high, but they claim that after dilution, the price per ton becomes very low. Then the dosage of the chemical added is very high, which is equivalent to no dilution. For example, suppose you need to take medicine to treat an illness: taking one tablet a day is the same as dividing that tablet into 8 parts and taking one part 8 times a day. But the chemicals produced by our manufacturer have a fixed concentration. The reason for this is to facilitate things: after the chemicals are delivered to the site, they can be added directly at a concentration of 2-6 Ppm. The dosing pump used for adding these chemicals is adjustable, with a range generally between 1-10 Ppm. Thus, the concentration of 2-6 Ppm specified by our manufacturer falls within the range of the metering pump’s capabilities, so there is no need for diluents or a different pump. When adjusting the dosing frequency of a metering pump, the error is not too large; it remains around the midpoint between the pump’s upper and lower limits. Therefore, based on the dosage required for typical systems, the manufacturer determines a suitable dilution concentration; the solution is diluted within the factory, and appropriate stabilizers are added to prevent instability that might arise from dilution from affecting the product’s stability, thus ensuring no issues occur during the warranty period. Only after that is the product sold to customers, which reduces the additional work that customers need to carry out, such as dilution. This is because the pure water used for dilution has specific requirements, and a stabilizer must be added. Many manufacturers of water treatment chemicals sell semi-finished products directly, as they are unable to ensure stability after dilution; they claim that this does it to reduce storage and logistics costs, which are then passed on as discounts to the customers. In reality, they are doing less work in this process. Moreover, if the customer dilutes the product themselves and problems arise, such as reduced water production due to scaling leading to shutdowns, the manufacturer can argue that there was an issue with the customer’s dilution process, since the pure water used was not provided by them. You can argue however you want. I really don’t understand why so many people who don’t know much about this subject prefer to use concentrated solutions. Why don’t the three major companies in the water treatment industry produce concentrated solutions? It’s only those third- or fourth-rate products that are made in this form. Use your own brain! Of course, it’s impossible to expect those who use the concentrate to understand, because after all, people with any amount of common sense wouldn’t work in factories. Just as you can’t expect civil servants not to commit corruption, those who want to become civil servants generally don’t have the skills to earn money; so what else can they do if they don’t commit corruption?

To put it simply, let’s say you are the client who wants to purchase chemicals. Just like other clients, you foolishly set a limit that the price per ton for purchasing scale inhibitors cannot exceed 30,000. The products I purchased myself were from Nalco or GE; their chemical costs 40,000 yuan per ton. So I found a small factory and had the substance diluted by half, which reduced the amount per ton to 2 tons at a cost of 20,000 yuan. This seemed like a cheap price. After the bidding process, I won the contract. Then I asked Nalco or GE for instructions on how to use this chemical. Based on an analysis of the quality of the water, they suggested using 3 ppm. But I advised using 8 ppm. Why? Because if I had suggested 6 ppm, it would have been the same as what the manufacturers recommended, and there would be no problem with its use. By adding 2 extra ppm, I could encourage customers to buy more of my product. Later, I diluted their product by three times again, and with 8 ppm still used, my profit tripled. This is why the market for water treatment chemicals is in such a chaotic state: some products yield extremely high profits, while others only have 5% profit margins; yet end-users consider the prices to be too high and refuse to buy them. I’d rather buy medications with high profits and low prices. So, as a GE salesperson, I think China is really chaotic. Sooner or later, I’ll do these tasks myself and trick you clients just the same. I’ll give you match point money to make you overjoyed. As a result, people laughed at you from behind, calling you stupid.

For example, with a corrosion inhibitor in a 25-kilogram bucket, if it is specified that 3 ppm should be used, that means 3 mg of the concentrated solution per liter of water. That is 3 parts per million. If the flow rate of water entering is 1000 M3/L, then for 1000 m3 of water in 1 hour, the amount required is 1000 tons, which equals 1,000,000 liters. An amount of 3 parts per million of the chemical is needed; simply put, 3 kg of the pure chemical is required for 1000 tons of water. So if your metering pump has a capacity of 6 L/h, you need to adjust it so that it dispenses 3 L of the liquid reagent per hour. Depending on the density of the reagent – whether it’s 1 kg/cm3 (where 1 cm3 equals 1 liter) or 1 t/m3 – the amount required remains 3 L/h. You then need to set the percentage of the metering pump to 50%. That’s fine. So if it operates 24 hours a day, 24*3L of chemical is needed; therefore you will require a large tank that can hold enough chemical for at least 3 days or 1 week. The amount required would be 24*3L*6 days, which gives you an idea of the size of the tank needed.

How much is the 8x concentrated solution you bought?