How to Choose and Use Water Treatment Chemicals Reasonably
The practice has shown that the use of water treatment chemicals is still the main method for the stable treatment of water quality.
For systems with a constant hydration water source, the concentration factor should be strictly controlled. For systems that do not have a constant hydration water source or partially supplement weak acid softened water, care should be taken to control the proportion of various hydration to ensure the stability of the system water quality. For systems that use alkalinity to adjust alkalinity, the rate of continuous dosing should be strictly controlled.
The water treatment chemical used should be familiar with the hardness tolerance, alkalinity tolerance and other properties of the chemicals.
Choose A Composite Water Stabilizer with Excellent Comprehensive Performance
Nitrogen-containing heterocyclic compounds such as mercaptobenzothiazole, benzotriazole, benzoimidazole, polybenzimidazole have a strong affinity for metallic copper. They combine with covalent and coordinate bonds with copper ions to form a dense protective film. The dissolution reaction of the non-ferrous metal is blocked by adsorption on the reactive site of the metal surface.
Therefore, the composite water stabilizer should contain a sufficient concentration of thiazoles or other substances having the same function to ensure good corrosion inhibition.
For water quality with high hardness, high alkalinity, high pH properties, the usual scale inhibitors (such as ATMP, EDTMP, HPMA, PAA, etc. commonly used in power plant circulating water systems) often fail to meet their requirements.
In this case, a new type of component having excellent hardness and alkali resistance properties should be used. Suitable agents for the “three high” poor water quality include PBTCA, PESA, POCA, PAPEMP, and other multi-component copolymers.
PBTCA has an excellent scale and corrosion inhibition properties. It is resistant to high temperatures and oxidation and has an excellent inhibitory effect on calcium carbonate scale. PBTCA has good synergy with organic phosphates, zinc salts and the like.
PESA (polyepoxysuccinic acid) has excellent chemical and thermal stability. It has excellent scale inhibition and dispersion effect on calcium carbonate and calcium sulfate. PESA and zinc salt compound has excellent corrosion and scale inhibition performance. It is a green water treatment chemicals with no phosphorus, non-nitrogen and good biodegradability.
POCA (phosphonocarboxylic acid) and PAPEMP (polyaminopolyether based organophosphoric acid) have high calcium tolerance and excellent chemical stability, oxidation resistance (nearly interacting with chlorine) and thermal stability. They have excellent scale inhibition and dispersion for calcium phosphate, calcium sulfate, zinc salt deposition, and iron oxides.
These water treatment chemicals are suitable for water treatment with high hardness, high alkalinity, high pH and high concentration multiple. It is the ideal agent for the treatment of “three high” water quality in China.
Other multi-component copolymers such as PCA, AA/AMPS copolymers, etc., also exhibit good performance in the three-high system. Only the selected formula has a reasonable composition and excellent performance to ensure good scale and corrosion inhibition effect and ensure the normal operation of the system.
Scientifically and Rationally Add The Carbon Steel Corrosion Inhibitor
Different industries have different industry habits.
In the circulating cooling water treatment of petrochemical systems, steel systems, and chemical industries, the standard commercial pharmaceutical dosage is 50-80 mg/L (according to the water supply).
In the circulating cooling water treatment of the power industry, the standard commercial pharmaceutical dosage is 5-10 mg/L (according to the water supply).
In the water treatment chemicals of the power industry, if the formulation of the medicament is reasonable and the water quality is not very bad, the dosage is sufficient to solve the corrosion problem of copper and the general scale inhibition problem. But it is impossible to consider the corrosion inhibition of carbon steel.
Because the organophosphorus compound as a corrosion inhibitor has a certain corrosion inhibition effect on carbon steel only under the condition of high concentration of the agent. In order to ensure that it can function at a lower concentration, it is usually necessary to add about 2 mg/L of the cathode corrosion inhibitor Zn2+.
Therefore, in the power system, if the corrosion inhibition of carbon steel is to be considered, the cathode corrosion inhibitor zinc sulfate should be added.
The operating conditions of the circulating water systems of different thermal power plants vary. The causes of corrosion and scaling of copper pipes are also different. However, all should find the cause of the problem in a targeted manner, take effective measures, try to ensure the normal operation of the circulating water, thus ensuring the normal operation of the unit and truly saving power generation costs.
- How to Choose and Use Water Treatment Chemicals Reasonably
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- Is PBTCA An Environmentally Friendly Scale Inhibitor
- Use of Circulating Water Treatment Chemicals in Power Plants
- Selection and Industrial Application of Scale and Corrosion Inhibitors
- Exploration of Oilfield Produced Water Treatment Technology