GB/T 44553-2024Technical specification for the energy saving of hot-dip galvanizing production lines (English PDF)

4.2 Galvanizing furnace body, combustion system and control system

4.2.1 Energy selection The heating energy of the galvanizing furnace shall be natural gas, liquefied petroleum gas, other clean energy or new energy. When natural gas is used for heating, the calorific value and pressure shall meet the following requirements:

a) The heat output is stable, and the fluctuation range allowed during production is within ±10%;

b) The pressure is stable, and the allowable fluctuation range of the workshop gas contact pressure is within ±5%.

4.2.2 Furnace type selection and main structure design

4.2.2.1 The furnace type can be a flat flame galvanizing furnace or a high-speed pulse galvanizing furnace.

4.2.2.2 The furnace body may adopt an I-shaped or U-shaped steel structure frame, and the furnace width should not exceed 1650 mm.

4.2.2.3 The zinc pot shall be equipped with a supporting device.

4.2.2.4 The galvanizing furnace shall be equipped with a zinc leakage pit of reasonable capacity.

4.2.3 Galvanizing furnace insulation

4.2.3.1 The side walls and furnace roof shall be made of ceramic fiber products, and the outer surface temperature of the furnace wall shall comply with the provisions of GB/T 16618.

4.2.3.2 On the premise of meeting the performance requirements such as temperature and load bearing, the furnace bottom masonry materials shall also be selected based on insulation effect, service life and economic rationality.

4.2.3.3 When refractory bricks and thermal insulation bricks are used to build the furnace bottom, the length and width of the refractory brick masonry are recommended to be integer multiples of 116 mm, and the masonry height is recommended to be an integer multiple of 68 mm.

4.2.3.4 When refractory castables are used to cast the furnace bottom as a whole, the temperature and load-bearing requirements shall be met.

4.2.4 Galvanizing furnace heat load

4.2.4.1 The zinc capacity of the zinc pot should be 15~20 times the designed production capacity per unit time.

4.2.4.2 The average heating intensity of the zinc pot wall shall not be less than 24 kW/(m2 - h).

4.2.4.3 The combustion device of appropriate specifications shall be selected according to the type and structural size of the galvanizing furnace, heating process, fuel type, heat load size and environmental protection requirements.

4.2.4.4 The heat supply of the galvanizing furnace shall be determined by heat balance calculation or selected according to empirical data.

4.2.4.5 The maximum heat load of the galvanizing furnace shall not exceed

1.3 times the rated heat load.

4.2.5 Energy saving of galvanizing furnace

4.2.5.1 The exhaust gas temperature of the galvanizing furnace should not exceed 600 °C, and the waste heat shall be recycled.

4.2.5.2 It is recommended to use a computer control system for the thermal system of the galvanizing furnace and effectively control the zinc liquid temperature according to the heating model.

4.2.6 Combustion system configuration of galvanizing furnace

4.2.6.1 The combustion system shall include low NOx burners, gas regulating valves, monitoring systems, induced draft fans and temperature sensors, and be equipped with automatic ignition and flame monitoring devices.

4.2.6.2 The burners of the flat flame galvanizing furnace shall be arranged reasonably according to the combustion chamber, the influence of temperature uniformity and the smoke exhaust method.

4.2.6.3 The center line of the burner of the high-speed pulse galvanizing furnace shall be arranged vertically on the center line of the fire channel.

4.2.6.4 The combustion system shall be equipped with a main shut-off valve with alarm

4.3 Waste heat system...

4.3.2 Waste heat system process design

4.3.2.1 When designing the process for collecting and utilizing the waste heat of the production line, energy-saving factors shall be considered, including fully collecting and utilizing the waste heat from production line combustion and workpiece cooling.

4.3.2.2 In the waste heat collection system, the waste heat collection equipment and automatic control system are used to automatically collect or utilize the waste heat from the production line online.

4.3.2.3 The waste heat utilization system uses the collected heat for drying, heating and steam production required by other processes, as well as office life, etc. until the heat energy is fully utilized.

4.3.3 Waste heat collection equipment

4.3.3.1 Waste heat collection equipment shall include heat recovery steam generator, pipelines, control system, accessories and instruments, etc.

4.3.3.2 The design and selection of flue-type heat recovery steam generators shall comply with the requirements of

GB/T 28056, YB/T 4483 and JB/T 7603.

4.3.3.3 The design and material selection of pipelines shall comply with the provisions of YB/T 4483. The pipeline surface shall have a thermal insulation layer, and the design of the thermal insulation layer shall comply with the provisions of GB 50126.

4.3.3.4 The design and selection of accessories and instruments for flue-type heat recovery steam generators shall comply with the provisions of YB/T 4483.

4.3.3.5 The thermal efficiency of the heat recovery steam generator shall not be less than 80%.

4.3.4 Waste heat utilization equipment

4.3.4.1 The heat exchange system shall select shell-and-tube polytetrafluoroethylene heat exchangers, stainless-steel coiled pipe heat exchangers or graphite heat exchangers according to the application conditions, and be equipped with waste heat collectors, heat exchangers, pipelines, valve groups and temperature and flow meters.

4.3.4.2 The design and selection of shell-and-tube PTFE heat exchangers shall comply with the requirements of GB/T 27698.3 and HG/T 4172.

4.3.4.3 Stainless-steel Coiled pipe heat exchangers should use pipes specified in GB/T 13296 or GB/T 24593.

4.3.4.4 The design, thermal conductivity and measurement method of graphite heat exchangers shall comply with the requirements of GB/T 8722 and

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