Chloride index for steam boilers?

Due to the high solubility of chlorides, it is difficult for them to precipitate in a solid phase; therefore, changes in chloride ions in the boiler are often used as an indirect indicator of changes in the salt content of the boiler water. The amount of continuous blowdown from our drum is determined based on the conductivity of the boiler water; it is required that the conductivity of the boiler water be ≤100μS/cm. It seems that the chloride ions in the boiler water can be used to calculate the conductivity of the boiler water; as for the exact method of calculation, I need to check the boiler operation manual.

Based on the capacity of your boiler, chloride ions are not actually a criterion for evaluation. You can check it; it seems there’s an issue with the water supply. You can change the water treatment method, for example by using a mixed-bed system

Reply to 3# Forever Love Yuanping: Could you be more specific? If, as you say, a 15-ton boiler doesn’t need to have its chloride level tested, then what needs to be tested?

Appendix 3: Standard of the People’s Republic of China **GB 12145-1999 – Quality criterion of water and steam for steam power equipment. Published on March 23, 1999; came into effect on October 1, 1999. Issued by the **Technical Supervision Bureau. Preface: This standard was first formulated and issued in December 1989; it has been in use for eight years now. In recent years, large-capacity, subcritical, supercritical units, once-through boilers, as well as new water treatment equipment have been put into operation one after another. The rapid development of 300 MW units as the main power plants has led to significant improvements in the technologies for corrosion and scale prevention in water treatment and thermal equipment, as well as in the monitoring of water and steam quality. New research findings were presented and new experiences were summarized, providing important technical basis for revising this standard. The format and other aspects of GB 12145-1989 have been revised in accordance with the national standard GB/T 1.1-1993 \"Guidelines for standardization work – Part 1: Rules for drafting and expressing standards – Section 1: Basic provisions for standard drafting\". The main revisions in this version are as follows: ──A preface has been added. ──To align with the international standard ISO drafting style, the subject matter and scope of Chapter 1 have been changed to Scope. ──Indices related to the control of supercritical units (DC boilers) have been added. ──Indices related to the control of neutralization treatment and combined water treatment for DC furnace feedwater have been added. ──Standardize the quality requirements for the cooling water of water-cooled generators with those specified in the generator operation procedures and the technical requirements for turbine-type synchronous motors (GB/T7064-1996), to facilitate on-site operation control. ──Added handling procedures for water vapor quality degradation. It is aligned with the relevant provisions of DL/T561-95 \"Guidelines for Chemical Monitoring in Thermal Power Plants\" formulated by the Ministry of Electric Power, emphasizing full-process management of chemical monitoring and implementing the principle of \"prevention first\" in chemical monitoring to prevent problems before they occur. ──To ensure the quality of the boiler water, a reference control standard for conductivity has been added to the boiler water control. ──To ensure the quality of demineralized water, the water quality standard for the turbidity of the effluent from the clarifier has been increased. ──Several major industrial water and steam quality standards or guidelines were referred to, including Japan’s JIS8223:1989 \"Quality Standards for Feedwater and Boiler Water in Natural Circulation Boilers, and Quality Standards for Feedwater in Once-Through Boilers\", Germany’s VGB-R450L:1988 \"Quality Standards for Feedwater, Boiler Water, and Steam in Boilers Operating at Pressures Above 68 bar\", the feedwater specifications for once-through boilers in Soviet power plants, the United States Electric Power Research Institute’s EPRI-CS-4629:1986 \"Guidelines for Chemical Operation Management in Thermal Power Plants\", as well as the water and steam quality standards for several imported units and supercritical units in China. The standard values specified in this standard are limit values, while the target values are intended to ensure the safer operation of the unit. This standard was proposed by the Ministry of Electric Power of the People’s Republic of China. This standard is under the jurisdiction of the Thermal Engineering Research Institute of the Ministry of Electric Power. The main drafting entity for this standard is the Thermal Engineering Research Institute of the Ministry of Electric Power. Main drafters of this standard: He Huichun, Li Guicheng, Chen Jie. Revised by Chen Jie and Cao Jieyu. This standard was first issued on December 29, 1989, and revised in March 1999. This standard is entrusted to the Thermal Engineering Research Institute of the Ministry of Electric Power for interpretation. Table of Contents Preface 1. Scope ...............................................1 2. Referenced Standards............................................1 3. Quality Standards for Steam........................................1 4. Quality Standards for Boiler Feedwater............................2 5. Quality Standards for Turbine Condensate...........................3 6. Quality Standards for Boiler Water.................................3 7. Quality Standards for Makeup Water..............................4 8. Quality Standards for Desuperheating Water......................5 9. Quality Standards for Drainage Water and Process Return Water......5 10. Quality Standards for Heat Network Makeup Water................5 11. Quality Standards for Cooling Water in Water-Cooled Generators......5 12. Quality Standards for Water and Steam during Startup of Shutted-Down or Standby Units.............................................6 13. Measures to Address Degraded Quality of Water and Steam..............7 1. Scope This standard specifies the quality standards for water and steam in thermal power generation units and steam-powered equipment during normal operation, as well as during the startup of shutted-down or standby units. This standard applies to thermal power generation units and steam power equipment with a boiler outlet pressure of 3.8 MPa to 25.0 MPa (gauge atmospheric pressure). 2 Referenced Standards The relevant provisions contained in the following standards become part of this standard by being referenced herein. At the time of standard publication, all versions shown are valid. All standards will be revised, and those using this standard should consider the possibility of adopting the latest versions of the following standards. GB/T 7064-1996 Technical requirements for turbine-type synchronous motors; GBJ 13-1986 Code for design of outdoor water supply systems; DL 434-1991 Provisions regarding the use of legal units of measurement in the field of chemical water treatment in power plants; DL/T 561-1995 Guidelines for chemical supervision of water and steam in thermal power plants. The testing methods shall comply with national standards. 3 Steam quality standards: The quality of saturated steam and superheated steam in natural circulation, forced circulation drum boilers, or once-through boilers shall comply with the specifications in Table 1. To prevent the accumulation of metal oxides inside the turbine, the copper and iron contents in the steam must comply with the specifications in Table 2. 4 Quality standards for boiler feedwater 4.1 The hardness, dissolved oxygen, iron, copper, sodium, silica, and conductivity (after hydrogen ion exchange) in the feedwater shall meet the requirements specified in Table 3. For slurry slag discharge furnaces and boilers originally designed to use fuel, the hardness of their feedwater, as well as the levels of iron and copper in it, shall meet the requirements specified for boilers of one pressure class higher. 4.2 The content of hydrazine and oil, as well as the pH value of the feed water, shall comply with the provisions in Table 4. Note: ① For units with a pressure of 3.8–5.8 MPa, the heater is made of steel pipes, and the pH of the feedwater can be maintained between 8.8 and 9.5. ②Power plants that use lime-sodium ion-exchanged water as make-up water should switch to controlling the pH of the turbine condensate, keeping it at no more than 9.0. ③For boilers with a pressure greater than 12.7 MPa, the total carbonate content in the feedwater (expressed as carbon dioxide) should generally be ≤1 mg/L. 4.3 The dissolved oxygen content, pH value, and conductivity of the feedwater subjected to oxygenation treatment in DC furnaces shall comply with the specifications in Table 5. 5 Quality standards for turbine condensate 5.1 The hardness, sodium and dissolved oxygen content, as well as the conductivity of the condensate, shall meet the requirements specified in Table 6. Note: ① When seawater, brackish water, or water with a high salt content but low hardness is used as cooling water for steam turbine condensers, it is also necessary to monitor the sodium content in the condensed water, etc ； ②When using a neutral treatment, dissolved oxygen should be controlled at 50–250 μg/L ； The conductivity should be less than 0.20 μS/cm. ③For condensate water that has been treated with a mixed-bed system, the sodium level can be relaxed to 10 μg/L. 5.2 The hardness, silica, sodium, iron, copper contents, and conductivity of the condensed water after treatment in a hydrogen-type mixed-bed reactor shall meet the specifications in Table 7. ① The sodium content in the condensate water after treatment in a mixed-bed system should meet the requirements for boiler water treatment. 6 Standards for the quality of boiler feedwater 6.1 The salt content, chloride ions, and silica content in the feedwater of drum boilers shall be determined through specialized tests on water and steam quality, and control can be carried out in accordance with the provisions in Table 8. ①All refer to the water from a single-stage evaporation furnace, with the total salt content serving as the reference indicator. ②When there is a steam washing device in the drum, its control parameters can be relaxed appropriately. 6.2 When a drum boiler is subjected to phosphate-PH control, the molar ratio of Na to PO4 in the boiler water should be maintained between 2.3 and 2.8. If the molar ratio of Na to PO4 in the boiler water is below 2.3 or above 2.8, a neutralizing agent can be added for adjustment. 7 Quality standards for make-up water: The quality of make-up water shall be such that it does not affect the quality of the feed water. 7.1 Quality standards for the water discharged from the clarifier The quality of the water exiting the clarifier (tank) must meet the requirements set for water quality in the subsequent treatment stage ； The turbidity of the water exiting the clarifier (tank) is normally <5 FTU, and <10 FTU for a short period of time. 7.2 For water entering the ion exchanger, attention should be paid to the levels of turbidity, organic matter, and residual chlorine in the water. Control according to the following values: Turbidity < 5 FTU (fixed-bed co-current regeneration) ； Turbidity < 2 FTU (fixed-bed convective regeneration) ； Residual chlorine < 0.1 mg/L ； Chemical oxygen demand < 2 mg/L (KMnO4, 30-minute water bath boiling method). 7.3 The effluent standards for ion exchangers can generally be controlled according to Table 9. ①The quality of the water output from the ion exchanger should meet the requirements for boiler water treatment. ②For the primary deionized water produced by a primary deionization-hybrid bed system, the conductivity can be relaxed to 10 μS/cm. 7.4 The mass of water and steam in the evaporators and steam generators shall comply with the following requirements: 1) For secondary steam, the sodium content shall be ≤500 μg/kg ； Silica content ≤ 100 μg/kg ； Free carbon dioxide content: It shall be set such that it does not affect the quality of the boiler feedwater. 2) Feed water for evaporators and steam generators: hardness ≤ 20 μmol/L ； Dissolved oxygen (after deoxygenation) ≤ 50 μg/L. 3) Water in the evaporator: The mass of water in the evaporator and steam generator shall be determined based on vapor quality tests. The phosphate content is generally between 5 mg/L and 20 mg/L; for evaporators that use boiler wastewater as make-up water, the phosphate content is not subject to this limit. 8 Quality standards for desuperheating water: When mixed desuperheating is used for boiler steam, the quality of the desuperheating water must ensure that the levels of sodium, silica, and metal oxides in the steam after desuperheating comply with the specifications given in Tables 1 and 2 of the steam quality standards. 9 Quality standards for demineralized water and process return water: The quality of demineralized water and process return water is controlled in accordance with the provisions in Table 10, on the premise that it does not affect the quality of the feed water. For the production return water, necessary testing items should also be added depending on its properties. 10 Quality standards for make-up water in the heating network: The quality of make-up water for the heating network is generally controlled in accordance with Table 11. 11 Quality standards for cooling water in water-cooled generators 11.1 The quality of the cooling water used in dual water cooling systems and those with independent rotor circulation shall meet the requirements specified in Table 12. 11.2 The hardness of the cooling water is specified according to the power of the turbo-generator: it shall not exceed 10 μmol/L for units with a power of 200 MW or less ； For capacities over 200 MW, it should be no more than 2 μmol/L. 11.3 When the stator windings of a steam turbine generator use an independent closed circulating water system, the conductivity of the cooling water should be less than 2.0 uS/cm. 12 Water and steam quality standards during the startup of shut-down and standby units 12.1 The quality of steam after the boiler is started, and before steam is supplied to the turbine, can be controlled in accordance with the specifications in Table 13; these values should reach the standard levels for normal operation within 8 hours. 12.2 When the boiler is started, the quality of the feedwater shall meet the requirements specified in Table 14, and it shall reach the standard values for normal operation within 8 hours. 12.3 When the unit is started, the condensate quality can begin to be recovered in accordance with the parameters specified in Table 15. 12.4 During unit startup, the quality of the drain water should be strictly monitored. The drain water from the high and low pressure heaters can be recycled when its iron content is not greater than 400 μg/L. 13 Handling when water vapor quality deteriorates When the quality of water vapor deteriorates, it is necessary to promptly check whether the samples taken are representative ； Are the test results correct? ； A comprehensive analysis of the changes in the mass of water and steam within the system should be conducted; once it is confirmed that the assessment is accurate, the situation should be reported immediately to the plant’s management along with appropriate recommendations. Leaders should instruct the relevant departments to take measures to restore water and steam quality to standard levels within an allowable time frame. The meanings of the following three levels of treatment values are as follows: Level 1 treatment value – there is a possibility of corrosion caused by impurities; it should return to the standard value within 72 hours. Secondary treatment value – There is a definite possibility of corrosion caused by impurities; it should return to the standard value within 24 hours. Tier 3 treatment value – Rapid corrosion is occurring; if the water quality does not improve, the boiler should be shut down within 4 hours. At each level of exception handling, if normal operation cannot be restored within the specified time, a higher-level handling method should be employed. For drum boilers, one way to restore the standard value is to operate at reduced pressure. 13.1 The treatment measures in case of abnormal water quality of condensate water (at the outlet of the condensate pump) are specified in Table 16. Note: ① In power plants cooled by seawater, the plant should be shut down urgently when the sodium content in the condensate exceeds 400 μg/L. 13.2 The treatment values in case of abnormal boiler feedwater quality are specified in Table 17. 13.3 The handling values in case of abnormal boiler feedwater are specified in Table 18. When water quality abnormalities occur, it is also necessary to measure the chloride content, sodium content, conductivity, and alkalinity in the boiler water in order to identify the cause and take appropriate measures. Engineer Wen: Hello! The above is GB12145-2008 \"Quality Standards for Water and Steam in Thermal Power Generating Units and Steam Power Equipment.\" The 3 boilers with a capacity of 75 tons/h and a pressure of 5.2 MPa in your facility should comply with the water and steam quality standards specified for pressures ranging from 3.8 to 5.8 MPa under this standard. That is: Water supply: hardness ≤ 2 μmol/L ； PH=8.8-9.2 ； Dissolved oxygen ≤15μg/L ； Fe2+≤50μg/L ； Cu2+ ≤ 10 μg/L. Boiler water: PH=9.0-11 ； PO43- = 5-15 mg/L. Steam: SiO₂ ≤ 20 μg/L ； Na+ ≤ 15μg/L ； There are no specifications for hydrazine in boiler feed water at 3.8-5.8 MPa. The function of hydrazine is to reduce the dissolved oxygen in water, thereby further preventing oxygen corrosion in boilers. Dissolved oxygen in feed water ≤ 15 μg/L ； No additional treatment with hydrazine is required. For boilers operating at 3.8-5.8 MPa, the control level for PO43- in the boiler water is 5-15 mg/L. The purpose of adding trisodium phosphate is to further remove residual hardness from the feed water and prevent scaling in the boiler. The amount of trisodium phosphate added for the first time when starting the boiler, in Kg: Kg = 1/a × 1/b × 1/1000 × V(c + 28.5 × H). The amount of trisodium phosphate added during boiler operation, in Kg/h: Kg/h = 1/a × 1/b × 1/1000 × (28.5 × H × WB/h + Wp/h × c). a – Percentage of PO43- in trisodium phosphate ； b – Effective content of trisodium phosphate ； c – Content of PO43- in boiler water, in mg/L ； V – Boiler water capacity in tons ； H – Boiler feedwater hardness in mmol/L; WB – Boiler make-up water volume in tons per hour; Wp – Boiler blowdown volume in tons per hour. The values above are theoretical calculations; to ensure stability in the dosing of chemicals in the system, it is necessary to measure the PO43- content in the boiler water for further verification. Stay in touch, Chen Ying

I wanted to paste it directly for you, but the table isn’t available; I’ll post it here so you can take a look

Thank you for your support, but the materials you provided are suitable for power station boilers and seem not to be appropriate for ordinary steam boilers. :(

Standard for Water Quality of the People’s Republic of China – Water Quality for Industrial Boilers. Standard of the People’s Republic of China GB1576—2001: Water Quality for Industrial Boilers, replacing GB1576—1996. Approved by the State Bureau of Quality and Technical Supervision on January 10, 2001; implemented on October 1, 2001. 1. Scope: This standard specifies the requirements for water quality during the operation of industrial boilers. 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 shall comply with 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/L1): ≤0.03, ≤0.03, ≤0.03; Total alkalinity, mmol/L2): 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/L3): ≤0.1, ≤0.1, ≤0.05; Dissolved solids, mg/L4): Without superheater: <4000, <3500, <3000; With superheater: <3000, <2500. SO2-3, mg/L4): 10–30, 10–30; PO3-4, 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/L6): ≤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-), 1/2CO2-3, 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 operating unit 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 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 re-evaluated 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 internal chemical treatment. 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: Requirements for feedwater of water-tube boilers – Suspended solids: ≤20 mg/L; Total hardness: ≤4 mmol/l; Total alkalinity: 8–26 mmol/l; pH (at 25°C): ≥7–10.12; Dissolved solids: <5000 mg/L. For pressure hot water boilers, external water treatment is required. For non-scaffolded 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; External 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 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 atmospheric pressure hot water boilers, deoxygenation of the feed water is advisable. 4. For DC (through-flow) boiler feedwater, external chemical water treatment shall 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).