Detail of GB/T 16508.3-2013

Introduction of GB/T 16508.3-2013

1 Scope This part of GB/T 16508 specifies the design and structural requirements for basic pressure parts of shell boilers, and provides the basic design requirements for cast-iron boiler (Appendix A), rectangular header (Appendix B) and water tube plate (Appendix C). This part is applicable to the design calculation for cylindrical parts subject to internal and external pressures, heads, tube plates, tension braces and foot rings as well as opening and reinforcement. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies. GB/T 1576 Water Quality for Industrial Boilers GB/T 2900.48 Electrotechnical Terminology of Boilers GB/T 9252 Method for Cycling Test of Gas Cylinders GB/T 12145 Quality Criterion of Water and Steam for Generating Unit and Steam Power Equipment GB 13271 Emission Standard of Air Pollutants for Boiler GB/T 16508.1-2013 Shell Boilers - Part 1: General Requirements GB/T 16508.2 Shell Boilers - Part 2: Material GB/T 16508.4 Shell Boilers - Part 4: Fabrication, Inspection and Acceptance NB/T 47013 (JB/T 4730) Nondestructive Testing of Pressure Equipment TSG G0001 Boiler Safety Technical Supervision Administration Regulation TSG G0002 Supervision Administration Regulation on Energy Conservation Technology for Boiler 3 Terms and Definitions For the purposes of this document, the terms and definitions established in GB/T 16508.1 and GB/T 2900.48 apply. 4 Symbols and Units Meanings and units of the symbols used in chapters and sections of this part are as follows: Et - the elasticity modulus of material upon temperature calculation, MPa; p - the calculating pressure, MPa; [p] - the maximum permissible operating pressure upon verifying calculation, MPa; pr - the rated pressure of boiler, MPa; p0 - the operating pressure, MPa; ts - the saturation temperature of medium corresponding to the calculating pressure (the nominal outlet temperature of hot water boiler), ℃; tc - the calculating temperature, ℃; tmave - the rated average temperature of medium, ℃; Δpa - the design additional pressure (the set pressure of relief valve), MPa; Δph - the liquid column static pressure borne by pressure part, MPa; Δpf - the additional pressure of dynamic resistance of medium flow, MPa; η - the correction coefficient; [σ]J - the permissible stress, MPa. 5 Basic Requirements for Design 5.1 Structural requirements 5.1.1 The boiler design shall comply with safety technical codes like "Boiler Safety Technical Supervision Administration Regulation" (TSG G0001) and "Supervision Administration Regulation on Energy Conservation Technology for Boiler" (TSG G0002); moreover, advanced technologies shall be adopted to make the product meet the requirements of safety, reliably, high efficiency, economy and environmental protection. 5.1.2 The calculating load to be considered and the load calculation to be carried out are determined according to the requirements of this part. The minimum required thickness of pressure part is determined according to relevant strength calculation formulas, stress analysis calculation formulas and requirements in this part. Where the strength of boiler pressure part is determined through test or other calculation method, relevant technical information and scheme as well as conditions and data of the test carried out shall be submitted to the Special Equipment Safety Technical Committee of General Administration of Quality Supervision, after evaluation by which, shall be submitted to the General Administration of Quality Supervision for approval; then trial fabrication and trial use may be carried out. 5.1.3 Wall thickness and length of shell and boiler furnace 5.1.3.1 Where the inside diameter of shell is greater than 1000mm, the wall thickness selected for shell shall not be less than 6mm; where the inside diameter of shell is not greater than 1000mm, the wall thickness selected for shell shall not be less than 4mm. 5.1.3.2 The inside diameter of boiler furnace shall not exceed 1800mm, and its wall thickness selected shall not be less than 8mm and not greater than 22mm; where the inside diameter of boiler furnace is less than or equal to 400mm, its wall thickness selected shall not be less than 6mm; for the reversal chamber of horizontal internal combustion boiler, the selected wall thickness of its shell shall not be less than 10mm and not greater than 35mm. 5.1.3.3 The wall thickness selected for the shell and tube plate in expansion connection shall not be less than 12mm. Structural design of expansion connection shall not be adopted for the tube with outside diameter greater than 89mm. 5.1.3.4 The calculating length of the plain boiler furnace of the horizontal shell boiler shall not exceed 2000mm; where butt connection is adopted for boiler furnace ends and tube plate flange, the calculating length of the plain boiler furnace may be increased to 3000mm. 5.1.4 The lowest safe water level of the steam boiler shall be 100mm higher than the highest fire line; however, for the horizontal shell boiler with the inside diameter not greater than 1500mm, the lowest safe water level shall be 75 mm higher than the highest fire line. The minimum and maximum safe water level of the boiler shall be indicated in the drawing. 5.1.5 The structural type of pressure component (part) as well as the arrangement of openings and welds shall avoid or reduce the combined stress and stress concentration as possible. The adopted weld type shall comply with the design document and GB/T 16508.4. The weld subject to non-destructive testing shall be designed as the type for which the required non-destructive testing may be carried out. 5.1.6 Full-penetration butt joint shall be adopted for main weld of the main pressure part for the boiler (e.g. longitudinal and circumferential welds of shell, boiler furnace, reversal chamber and header, as well as butt welds of head, tube plate, boiler furnace top and foot ring); overlapped structure shall not be adopted for the weld of boiler pressure part; splicing shall not be adopted for tension brace. 5.1.7 Where the inside diameter of shell is greater than 1000mm, man-hole shall be arranged on the shell or head (tube plate); where personnel cannot enter into the boiler due to structural constraint, only inspection hole may be arranged; for the boiler with smoke tube arranged in shell, the arrangement of man-hole and inspection hole shall give consideration to the overhaul demand of both upper and lower parts of shell; for the shell boiler with inside diameter of shell as 800~1000mm, at least one inspection hole shall be arranged on shell or head (tube plate); the quantity of hand-holes arranged at the lower part of vertical shell boiler shall meet the requirements of cleaning and inspection and shall not be less than 3. 5.1.8 For the boiler with furnace, the combustion shall be completed in furnace. Water entering into the boiler shall not directly scour the boiler furnace. For the boiler with inside diameter of furnace greater than 1400mm or heat input greater than 12MW, at least 3 measuring points shall be arranged in boiler for temperature measurement. 5.1.9 The hydraulic test pressure shall meet the requirements of GB/T 16508.1. 5.1.10 Corrosion allowance The corrosion allowance shall meet the following requirements: a) For the pressure parts with nominal thickness δ>20mm and all plain components, the corrosion allowance may be 0mm; b) For the pressure parts with nominal thickness δ≤20 mm, the minimum corrosion allowance may be taken as 0.5mm; c) In the case of possible severe corrosion, the value of corrosion allowance may be correspondingly increased. 5.2 Performance requirements 5.2.1 Design performance 5.2.1.1 The manufacturer shall ensure that the boiler reaches the rated evaporation or rated thermal power under design conditions, and shall provide the load range for economical operation of boiler. 5.2.1.2 The steam quality of boiler, where operating under design conditions, shall reach the following indexes: For water-fire tube boiler and shell boiler, the steam humidity of saturated steam boiler shall not be greater than 4%; the steam humidity of superheated steam boiler at the superheater inlet shall not be greater than 1%; the salt content of superheated steam shall not be greater than 0.5mg/kg. The temperature deviation tss of superheated steam of industrial steam boiler shall meet the following requirements: a) Where tss≤300℃, its deviation range is ( )℃; b) Where 300℃

Contents of GB/T 16508.3-2013

Foreword I 1 Scope 2 Normative References 3 Terms and Definitions 4 Symbols and Units 5 Basic Requirements for Design 6 Cylindrical Parts Subject to Internal Pressure 7 Cylindrical Boiler Furnace, Circular Flue, Smoke Tube and Other Part Subject to External Pressure 8 Convex Head, Boiler Furnace Top, Hemispherical Boiler Furnace and Convex Tube Plate 9 Flat Plates and Tube Plates with Tension Brace (Support and Reinforcement) 10 Tension Braces and Reinforcing Parts 11 Flat Cover and Cover Plate 12 Foot Ring 13 Opening and Opening Reinforcement 14 Welded Tee Junction 15 Verification Method for Determining Maximum Permissible Operating Pressure of Part Appendix A (Informative) Design Calculation of Pressure Part on Cast-iron Boiler Appendix B (Informative) Design Calculation of Rectangular Header Appendix C (Informative) Design Calculation of Water Tube Plate