1 Scope
This standard specifies water quality criteria of industrial boiler in operation.
This standard is applicable to fixed steam boiler and steam-water multifunctional boiler with water as medium whose nominal outlet steam pressure is less than 3.8 MPa, as well as fixed pressurized hot water boiler and constant-pressure hot water bolier with water as medium.
This standard is not applicable to boilers made of aluminium products.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments (excluding amending error in the text) to, or revisions of, any of these publications do not be applied. However, the parties whose enter into agreement according to these specifications are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to these specifications.
GB/T 601 Chemical Reagent -- Preparations of Standard Volumetric Solutions
GB/T 603 Chemical Reagent -- Preparations of Reagent Solutions for Use in Test Method (GB/T 603-2002, ISO 6353-1: 1982, Rcagents for Chemical Analysis -- Part 1: General Test Methods, NEQ)
GB/T 6682 Water for Analytical Laboratory Use -- Specification and Test Methods (GB/T 6682-2008, ISO 3696: 1987, MOD)
GB/T 6903 Analysis of Water Used in Boil and Cooling System - General Rule
GB/T 6904 Water Used in Industrial Circulating Cooling System and Boiler -- Determination of pH
GB/T 6907 Analysis of Water Used in Boil and Cooling System -- The Sampling Method of Water
GB/T 6908 Analysis of Water Used in Boil and Cooling System -- Determination of Electrical Conductivity
GB/T 6909 Analysis of Water Used in Boiler and Cooling System -- Determination of Hardness
GB/T 6913 Analysis of Water Used in Boiler and Cooling System -- Determination of Phosphate (GB/T 6913-2008, ISO 6878: 2004, Water quality -- Determination of phosphorus -- Ammonium molybdate spectrometric method, NEQ)
GB/T 12145 Quality Criterion of Water and Steam for Generating Unit and Steam Power Epuipment
GB/T 12151 Analysis Method of Boiler Water and Cooling Water - Determination of Turbidity (Formazin turbidity)
GB/T 12152 Water for Boiler and Cooling System -- Determination of Mineral Oil
GB/T 12157 Water for Industrial Circulating Cooling System and Boiler -- Determination of Dissolved Oxygen (GB/T 12157-2007, ISO 5813: 1983, Water quality -- Determination of dissolved oxygen -- Iodimetric method, NEQ)
GB/T 15453 Water for Industrial Circulating Cooling System and Boiler -- Determination of Chloridion
DL/T 502.1 Analytical Methods of Steam and Water in Power Plants -- Part 1: General Rules
DL/T 502.25 Analytical Methods of Steam and Water in Power Plants -- Part 25: Determination of Iron (Spectrometric method using sulphosalicylic acid)
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
Raw water
The water not applied any treatment.
3.2
Softened water
The water whose all or a majority of calcium and magnesium ions are removed.
3.3
Demineralized water
The general name of finished water whose all or a majority of impurities like suspended matter, inorganic matter and positive ions are removed through effective technology treatment.
3.4
Make-up water
The treated water that is used to supplement boiler blowdown and steam-water loss.
3.5
Boiler feed water
The water directly entering boiler, which generally consists of make-up water, back water and drainage.
3.6
Boiler water
The water that raise steam or becomes hot by absorbing heat in operating boiler.
3.7
Back water
The water that steam and hot water made by boiler come back to boiler feed water after doing works or heat exchange.
3.8
Internal chemical boiler water treatment
The method that a certain amount of chemicals is dosed into boiler in order to avoid and reduce boiler scalling or corrosion.
3.9
External boiler water treatment
The method that harmful impurity caused by boiler operation is applied with necessary technology before the raw water enters into the boiler.
4 Water Quality Ccriteria
4.1 Water quality of natural cycle steam boiler and steam-water multifunctional boiler
4.1.1 Water quality of natural-cycle steam boiler and steam-water multifunctional boiler adopting external boiler water treatment
Water quality of boiler feed water and boiler water for natural-cycle steam boiler and steam-water multifunctional boiler adopting external boiler water treatment shall meet the requirements specified in Table 1.
