1.0.1 This code is formulated with a view to ensuring conformity of the ash handling design of fossil-fired power plant with the requirements of safety, reliability, advanced technology, economy and suitability, unifying and defining the construction standards, actively utilizing the advanced technologies, processes, materials and equipment proven through operation practice or industrial test.
1.0.2 This code is applicable to the ash handling design of solid fossil fuel power plant, municipal solid waste incineration power plant and straw power plant.
1.0.3 The ash handling design of fossil-fired power plant shall meet the relevant requirements of the current national standards "Code for Design of Large and Medium Fossil Fired Power Plants" (GB 50660) and "Code for Design of Small Fossil Fired Power Plant" (GB 50049).
1.0.4 The ash handling design shall create conditions for comprehensive utilization of ash.
1.0.5 The ash handling system shall be planned uniformly according to the construction scale of power plant and constructed by stages according to the construction schedule of unit. If construction by stages is unreasonable upon technical and economical comparison, it may be built-up at a time.
1.0.6 The ash handling system may adopt pneumatic, mechanical and hydraulic conveying systems or a combined system and should meet the following requirements:
1 Slag handling by dry bottom furnace should adopt mechanical slag handling system, fly ash handling by pulverized coal fired boiler should adopt pneumatic ash handling system and mill reject handling by medium speed coal mill should adopt simple mechanical conveying system. Where the conditions are suitable, other types of conveying systems may also be adopted.
2 Where dry ash storage yard is adopted, the off-site conveying system of ash, mill reject and gypsum should adopt automobile transportation.
3 Where wet ash storage yard is adopted, the off-site conveying system of ash should adopt hydraulic pipeline conveying.
1.0.7 The design capacity of off-site ash handling system shall be determined according to the specific engineering conditions and the implementation conditions of comprehensive utilization of ash.
1.0.8 The ash handling system shall be designed according to the ash discharge amount of boiler when it fires the design fuel at the working condition of maximum continuous evaporation, be checked according to the ash discharge amount of boiler when it fires the check fuel and be left with certain allowance.
1.0.9 The ash amount discharged from each part of boiler shall be calculated according to the method given in Appendix A of this code. The ash and slag ratio shall adopt the data provided by the boiler factory, and if the data is unavailable, the ash and slag ratio may adopt the value given in Table A.0.3 in the Appendix A of this code. The mill reject amount discharged by the medium speed coal mill should be calculated according to the method given in Appendix B of this code.
1.0.10 Mature operation practice experience of engineering with similar conditions shall be provided for the design of pneumatic conveying system and auxiliary storage facilities; where mature operation practice experience is unavailable, test, study and technical demonstration on the basis characteristics as well as the conveying and storage characteristics of materials shall be carried out. Where the material density data is unavailable, values may be taken according to the requirements of Appendix C of this code.
1.0.11 Necessary overhaul lifting facility shall be installed at the centralized layout place of ash handling equipment, and shall meet the following requirements:
1 The rated lifting capacity of lifting facility shall be determined according to the heaviest overhaul lifting component; the installation elevation of lifting facility shall be determined according to the lifting height of the required lifting equipment.
2 The overhaul lifting facility shall be selected in accordance with the following requirements:
1) Repair and lifting facilities shall be arranged for equipment with lifting capacity of 1t or above, pipe fittings and valve required for repair;
2) Electric lifting facilities should be arranged for frequently used equipment with lifting capacity of 3t or above;
3) Electric lifting facilities shall be arranged for equipment with lifting capacity of 10t or above;
4) Where it is inconvenient to arrange fixed maintenance and repair platform, mobile lifting facilities may be arranged;
5) Movable or fixed lifting facilities may be arranged for equipment outdoors according to surrounding conditions.
1.0.12 Necessary cleaning facilities shall be arranged at the centralized layout place of ash handling equipment and the buildings or structures with ash handling system, and dust-proof and suppression measures shall be adopted at the loading and unloading places.
1.0.13 The water and gas pipeline design of ash handling system shall meet the requirements of the current professional standards "Code for Design of Thermal Power Plant Steam/Water Piping" (DL/T 5054) and "Code for Oil/Gas Piping Design of Fossil Fuel Power Plant" (DL/T 5204), and the two phase pipeline design of ash handling system may be implemented by reference to the standards.
1.0.14 The design of ash handling system and ancillary facilities shall meet the requirements of the current professional standards "Design Code for Occupational Safety of Fossil-fired Power Plant" (DL 5053), ""Design Code for Occupational Health of Fossil-fired Power Plant" (DL 5454) and "Code for Designing Insulation and Painting of Fossil Fuel Power Plant" (DL/T 5072).
1 General Provisions
2 Terms
3 Pneumatic Ash Handling System
3.1 Basic Requirement
3.2 Positive Pressure Pneumatic Conveying
3.3 Negative Pressure Pneumatic Conveying
3.4 Pneumatic Ash Conveying Pipeline
3.5 Air Slide
3.6 Dry Ash Classifying System
4 Hydraulic Ash Handling System
4.1 Basic Requirement
4.2 Water Supply for Ash Handling System
4.3 Hydraulic Jet Pump
4.4 Ash Trench
4.5 Ash Slurrying Facilities
4.6 Centrifugal Ash Slurry Pump
4.7 Plunger Ash Slurry Pump
4.8 Dewatering Bin and Settling Facilities
4.9 Slag Settling Pond
4.10 Hydraulic Ash Conveying Pipeline
5 Mechanical Ash Handling System
5.1 Basic Requirement
5.2 Air-cooled Type Slag Conveyor
5.3 Submerged Scraper Conveyor
5.4 En-masse Conveyor
5.5 Vertical Bucket Elevator
5.6 Bucket Conveyor
6 Mill Reject Conveying System
6.1 Basic Requirement
6.2 Simple Mechanical Conveying
6.3 Hydraulic Jet Pump Conveying
6.4 Mechanical Conveying
7 Compressed Air Supply System
7.1 Basic Requirement
7.2 Air Compressor and Treatment Facilities of Compressed Air
7.3 Rotary Blower and Vacuum Pump
8 Material Storage and Unloading System
8.1 Basic Requirement
8.2 Ash Silo and Ash Hopper
8.3 Slag Bin and Mill Reject Bin
8.4 Unloading System and Equipment Selection
9 Off-site Conveying System
9.1 Basic Requirement
9.2 Automobile Transportation
9.3 Belt Conveyor
9.4 Ship Transportation
10 Ash Handling System for CFB Boiler
10.1 Basic Requirement
10.2 Slag Handling System
10.3 Limestone Powder Handling System
11 Ash Handling System for Municipal Solid Waste Incineration Power Plant
11.1 Basic Requirement
11.2 Slag Handling System
11.3 Ash Handling System
12 Ash Handling System for Straw Power Plant
12.1 Basic Requirement
12.2 Mechanical Ash Handling System
12.3 Pneumatic Ash Handling System
12.4 Ash Storage
13 Slime Pipelines Conveying System
13.1 Basic Requirement
13.2 Slime Pipelines Conveying
13.3 Equipment Selection
13.4 Slime Pump House
14 Design Requirements for Relevant Specialties
14.1 Boiler and Auxiliaries
14.2 I&C and Electrical
14.3 Civil Engineering and Hydro-structure
14.4 Hydraulic and Chemical
14.5 Heating and Ventilating
14.6 General Plan Transportation
Appendix A Calculation of Ash Amount
Appendix B Calculation of Mill Rejects Amount
Appendix C Density Lists of Material
Appendix D Calculation of Reynolds Number
Explanation of Wording in this Code
List of Quoted Standards
