Seeking knowledge related to alkalinity

For different fields or industries, the range of alkalinity varies. Alkalinity is measured in petroleum products, in water quality tests, and in certain additives; these are all different types of alkalinity. What type of alkalinity does the landlord want to measure?

Your question isn’t very clear; could you provide more details?

This is the sulfuric acid area; I assume LZ is asking about the alkalinity of the boiler feed water. Alkalinity refers to all the substances in water that can neutralize strong acids, as well as the total amount of substances that can accept protons H+. It is a measure of the water’s ability to buffer acids. The main requirements for water quality in boilers include hardness, alkalinity, and conductivity.

The friend on the 4th floor is really smart; it’s a shame the introduction wasn’t detailed enough. I hope more can be added. I mainly want to understand the components that make up the alkalinity of feedwater and boiler water, how to accurately calculate the alkalinity content of various salts, and the relationship between alkalinity and pH, among other things. :dizzy:

The concentrations of all substances that can accept hydrogen ions, such as OH, HCO3, and CO3.

The concentrations of all substances that can accept hydrogen ions, such as OH, HCO3, and CO3.

The total amount of substances that can accept hydrogen ions is collectively referred to as alkalinity

This post was last edited by jackson404 on 2010-6-2 08:43. The alkalinity of water refers to the amount of substances in water that can accept H+ ions to undergo neutralization reactions with strong acids. The substances that produce alkalinity in water are mainly carbonate alkalinity generated by carbonates, bicarbonate alkalinity generated by bicarbonates, and hydroxide alkalinity resulting from the presence of hydroxides and the hydrolysis of strong bases and weak acids. Therefore, alkalinity represents the sum of CO32-, HCO3-, OH-, and other weak acid salts in water. The aqueous solutions of these salts are all alkaline and can be neutralized with acid. However, in natural water, alkalinity is mainly composed of salts of HCO3-. It can be assumed that the total alkalinity M=+2+-; when the pH value is greater than 7.0, this value can be omitted. Thus, M=c(Bx-)=++ mol/L. The substances that contribute to alkalinity in water, namely carbonates and bicarbonates, can coexist, and carbonates and hydroxides can also coexist. However, bicarbonates and hydroxides cannot coexist; they undergo the following reaction in water: HCO3- + OH- == CO32- + H2O. It can be seen that carbonates, bicarbonates, and hydroxides can exist separately in water. In addition, there are two other combinations of alkalinity, so there are five forms of alkalinity in water, namely: (1) Bicarbonate alkalinity HCO3- ； (2) Carbonate alkalinity CO32- ； (3) Hydroxide alkalinity OH- ； (4) Bicarbonate and carbonate alkalinity HCO3- + CO32- ； (5) Carbonate and hydroxide alkalinity CO32- + OH-. In short: Alkalinity is the quantitative capacity of an aqueous medium to react with hydrogen ions, and it is determined quantitatively by titrating a certain volume of water sample with a strong acid standard solution to a specific pH value. The test results are expressed as a mass solution equivalent to calcium carbonate, in mg/L. When titration is carried out until the phenolphthalein indicator changes from red to colorless, the pH value of the solution is 8.3, indicating that the hydroxide ions (OH-) in the water have been neutralized and all carbonates have been converted into bicarbonates. The result of this titration is referred to as \"phenolphthalein alkalinity\". When titration is carried out until the methyl orange indicator changes from yellow to orange-red, the pH of the solution is 4.4–4.5, indicating that the bicarbonates in water (both those originally present and those formed from carbonates) have been neutralized. The result of this titration is referred to as \"total alkalinity\". Low alkalinity boiler water is a precursor to boiler corrosion. Therefore, the national standard GB-T14419-93 includes methods for the analysis of water used in boilers and cooling systems, specifically a method for determining alkalinity. It can be used as a reference. pH value is an indicator that shows the acidity or alkalinity of water. It is also known as acidity level. Pure water serves as the reference point (pH = 7); values higher than 7 indicate alkalinity ； PH<7 is acidic ； PH=7 is neutral. The pH value is actually the negative derivative of the hydrogen ion concentration in a solution; it has no units. pH = -lg ； At 20 degrees, POH = -lg, and * = 10 to the power of -14. In other words, PH + POH = 14