Boiler feedwater data

Standards of the People’s Republic of China ** GBl576—2001 Standards for Water Quality in Industrial Boilers Replaces GBl576—1996 I. Scope The standards for water quality in boilers specify the requirements regarding water quality during the operation of industrial boilers. The boiler water quality standards apply to fixed steam boilers and dual-purpose steam and water boilers that use water as the working medium, with a rated outlet steam pressure of 2.5 MPa or less; they also apply to fixed pressurized hot water boilers and atmospheric pressure hot water boilers that use water as the working medium. II. Boiler Water Quality Standards 1. For feedwater in steam boilers and dual-purpose steam and water boilers, external chemical water treatment is generally required, and the water quality should meet the specifications in Table 1. Table 1: Parameters Feedwater Boiler Water >1.0 >1.6 >1.0 >1.6 Rated steam pressure, MPa ≤1.0 ≤1.0 ≤1.6 ≤2.5 Suspended solids, mg/L ≤5 ≤5 ≤5 Total hardness, mmol/L ≤0.03 ≤0.03 ≤0.03 Without superheater: 6–26, 6–24, 6–16 respectively Total alkalinity, mmol/L With superheater: ≤14, ≤12 pH (at 25°C): ≥7, ≥7, ≥7 respectively; 10–12, 10–12, 10–12 respectively Dissolved oxygen, mg/L: ≤0.1, ≤0.1, ≤0.05 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-), 1/2CO2-3, 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, provided that the user obtains approval from the local boiler and pressure vessel safety supervision authority. 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 supplied 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-) measurement can be used for indirect control; however, the ratio relationship between dissolved solids and conductivity or chloride (Cl-) must be determined through testing. 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 combined 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. Table 2: Parameters for feedwater of water boilers – Suspended solids, mg/L: ≤20; Total hardness, mmol/l: ≤4; Total alkalinity, mmol/l: 8–26; pH (25°C): ≥7, 10–12; Dissolved solids, mg/L: <5000. For pressure-bearing hot water boilers, external water treatment is required. For non-frame type pressure-bearing 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: Treatment methods – Chemical treatment inside the boiler vs. chemical treatment outside the boiler. For feed water and boiler water: Suspended solids, mg/L: ≤20, ≤5; Total hardness, mmol/L: ≤6, ≤0.6; pH (at 25°C): ≥7, 10–12, ≥7. Dissolved oxygen, mg/L: ≤0.1. Oil content, mg/L: ≤2, ≤2. 1) The pH value of the boiler water is maintained 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; for pressure hot water boilers with a rated power of less than 4.2 MW and for atmospheric pressure hot water boilers, the feed water should 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 parameters 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).

Teacher upstairs, could you upload the original version of this material so that I can download it? Thank you!