The boiler water has hardness

It’s from the internet, and it seems the issue still isn’t clearly explained. Actually, it’s one sentence in 【concise】 form. Just like the concentration ratio of circulating water. Both the boiler feedwater and the water inside the boiler need to be tested; hardness refers to the amount of calcium and magnesium ions in the water that can cause scale formation. Alkalinity is a necessary condition to prevent boiler scaling. That set of procedures are the water treatment processes and operational standards. For the specific standards, see below. Water quality standards for low-pressure boilers (GB1576-2001, 2001) – Water quality for industrial boilers; replaces GBl576—1996. 1. Scope: These standards specify the water quality requirements for industrial boilers during operation. This standard applies to fixed steam boilers and steam-water dual-purpose boilers that use water as the working medium, with a rated outlet steam pressure of 2.5 MPa or less; it also applies to fixed pressurized hot water boilers and atmospheric pressure hot water boilers that use water as the working medium. II. Water Quality Standards 1. For feed water in steam boilers and dual-purpose steam and water boilers, external chemical water treatment is generally required, and the water quality must meet the specifications in Table 1. Table 1: Parameter – Feed Water / Boiler Water; Rated Steam Pressure, MPa: ≤1.0, >1.0, >1.6; ≤1.0, >1.0, >1.6; ≤1.6, ≤2.5, ≤1.6, ≤2.5. Suspended solids, mg/L: ≤5, ≤5, ≤5. Total hardness, mmol/L: 1) ≤0.03, ≤0.03, ≤0.03. Total alkalinity, mmol/L: 2) Without superheater: 6–26, 6–24, 6–16; With superheater: ≤14, ≤12. pH (25°C): ≥7, ≥7, ≥7; 10–12, 10–12, 10–12. Dissolved oxygen, mg/L: 3) ≤0.1, ≤0.1, ≤0.05. Dissolved solids, mg/L: 4) Without superheater: <4000, <3500, <3000; With superheater: <3000, <2500. SO2-3, mg/L: 4) 10–30, 10–30. PO4-3, mg/L: 10–30, 10–30. Relative alkalinity (free NaOH/dissolved solids): 5) <0.2, <0.2. Oil content, mg/L: ≤2, ≤2, ≤2. Iron content, mg/L: 6) ≤0.3, ≤0.3, ≤0.3. 1) The basic unit for hardness in mmol/L is c(1/2Ca2+, 1/2Mg2+); the same applies hereinafter. 2) The basic units for alkalinity in mmol/L are c(OH-), 1/2CO3^2-, and HCO3-, the same applies hereafter. For boilers that have low requirements regarding steam quality and do not include a superheater, the upper limit for the alkalinity value can be appropriately increased, subject to approval from the local boiler and pressure vessel safety supervision authority by the user entity. 3) Deoxidization is required when the rated evaporation capacity of the boiler is 6 t/h or more. For boilers with a rated evaporation capacity of less than 6 t/h, deoxidization measures should be applied to the feedwater in case of local corrosion; the oxygen content in the feedwater for boilers supplying steam to turbines should be less than or equal to 0.05 mg/L. 4) If it is difficult to determine the dissolved solids, conductivity or chloride (Cl-) levels can be used as indirect indicators; however, the ratio between dissolved solids and conductivity, or between dissolved solids and chloride (Cl-), must be determined through experimentation. This ratio should also be rechecked and adjusted regularly. 5) The relative alkalinity of fully welded structure boilers can be left uncontrolled. 6) Only for fuel and gas boilers. 2. Steam boilers and dual-purpose steam and water boilers with a rated evaporation capacity of 2 t/h or less, and a rated steam pressure of 1.0 MPa or less (provided that there are no special requirements regarding the quality of steam and water) can also employ chemical treatment inside the boiler. However, strict supervision must be exercised over scaling, corrosion, and water quality in the boiler; proper dosing, sludge removal, and cleaning procedures must be carried out, and the water quality must meet the requirements specified in Table 2. Items: Suspended solids in feedwater for boilers, mg/L ≤20; Total hardness, mmol/l ≤4; Total alkalinity, mmol/l 8–26; pH (25°C) ≥7–12; Dissolved solids, mg/L <5000. Table 2:3. Feedwater for pressure hot water boilers requires external water treatment. For non-skeled pressure hot water boilers with a rated power of 4.2 MW or less, as well as atmospheric pressure hot water boilers, internal chemical treatment can be used; however, close monitoring of scaling, corrosion, and water quality is necessary, and proper chemical treatment must be carried out, with the water quality meeting the requirements specified in Table 3. Table 3: Items. In-boiler chemical treatment; Outside-boiler chemical treatment. Feed water; Boiler water; Feed water; Boiler water. Suspended solids, mg/L: ≤20, ≤5. Total hardness, mmol/L: ≤6, ≤0.6. pH (25°C): 1) ≥7, 10–12, ≥7. Dissolved oxygen, mg/L: 2) ≤0.1. Oil content, mg/L: ≤2, ≤2. 1) The pH value of the boiler water is controlled between 10 and 12 by adding chemicals. 2) The feed water for pressure hot water boilers with a rated power of 4.2 MW or more should be deoxygenated; the feed water for pressure hot water boilers with a rated power of less than 4.2 MW and for atmospheric pressure hot water boilers should also be deoxygenated as much as possible. 4. For DC (through-flow) boiler feed water, external chemical treatment should be employed, and the water quality shall comply with the standards specified in Table 1 for a rated steam pressure of greater than 1.6 Mpa and less than or equal to 2.5 Mpa. 5. The water quality specifications for waste heat boilers and electric heating boilers shall meet the requirements of boilers of the same type and with the same parameters. 6. The water quality testing methods shall be carried out in accordance with Appendix A (the appendix to the standards). If the hardness is too high, a fully automatic water treatment device can be used; if the alkalinity is too high, wastewater can be discharged in appropriate amounts to address the issue.

Impurities such as rust; sometimes it may also be due to inadequate purification of the water

Check whether the sampling cooler coil is leaking, by turning on and off the corresponding valves to determine this