Air preheater heat transfer components, installation, use, maintenance instructions Hoisting components:
Qixing power supply heat exchanger components are generally two kinds of materials, one for the low-carbon steel heat exchanger components, component thickness between 0.5 ~ 0.6mm, used in the hot end; the other for the enamel heat exchanger components coated After the thickness of 1.15 ~ 1.2mm, used in the cold side. Because the heat transfer components are rolled by the sheet, in the transport, lifting the end of the component must be avoided damage, otherwise, will cause the deformation of components, enamel shedding and other issues, the general Foundation will provide a dedicated spreader, To lift the heat transfer element cartridge. Prohibited the use of ordinary carbon steel spreader made! . Due to fatigue resistance of carbon steel is poor, prone to decoupling, fracture, etc., will cause a great security accident!
Heat transfer components Transportation Storage:
Heat transfer components in the loading and transportation process must be put neatly code, and tie the protective rope, covered with rain cloth, before unloading the car, the rain and rain to shake to the car, forbidden shaking scattered on the components. The site of the heat exchange components must be free of water, debris, and other places than the cement plains, and with a rain cloth to protect, prohibit loading and unloading in the rainy day heat exchanger components, otherwise it will cause corrosion.
Heat exchanger installation protection:
In the installation, avoid touching the steel column, electric hoist hook, guide chain and other metal objects in the hoisting grid, a certain support to check the solid steel, and clean up welding slag, scrap and other debris, When the components transferred to the grid, one by one placed asbestos blanket, the end of the components to be protected to prevent the next installation process damage to the components!
Component fouling Corrosion control:
The actual combustion of the boiler almost all the fuel contains sulfur, the boiler combustion process will be 2 to 6% of the sulfur dioxide into sulfur trioxide, and flue gas in the water reaction, denitrification ammonia escape reaction of ammonia sulfate formation , In the cold-side heat transfer element surface will form a sticky wet corrosive, in addition to the flue gas in the flue gas and catalyst in the process of blowing the particles, fragments and other damage, and thus continue to corrosion heat exchanger components, plugging Heat transfer channel, resulting in poor heat transfer heat exchanger components, short life, large pressure and other issues.
SO2 / SO3 conversion is not more than 1% (molar ratio); to avoid the air preheater in the control of the rate of the escape of ammonia in the general control of 2.3mg / m3; The "cold junction temperature" (flue gas outlet temperature + air inlet temperature) is below the recommended minimum value for long periods of operation. Avoiding water leakage from the economizer or heater failure increases the dew point of the flue gas, Road leakage should be promptly repaired.
Fire prevention measures:
In the ignition, low-load operation, poor combustion conditions, the incomplete combustion of coal, and ignition oil parcels will appear secondary combustion, and thus must prevent the surface of the fuel element of the heat transfer element deposition, otherwise it will cause air pre- Fire situation.
The air preheater rotor must be kept rotating; keep blowing soot regularly to ensure that the heat exchanger surface clean; pay close attention to the air preheater and air temperature, when the temperature anomalies occur, Should be promptly investigated and eliminated; in the event of secondary ignition, must keep the blower, induced draft fan, sootblower, low pressure water in a normal state; fire monitoring system should be maintained in normal working condition.
Check before and after running:
1, check and thoroughly clean the upper part of the air pre-heater, the flue inside the temporary pedal, scrap, support, etc.;
2, check the sootblower barrel bracket welding is solid, reliable, if necessary, to strengthen measures to prevent soot stent off stuck rotor;
3, using the handle plate rotor 2 laps to see whether the free rotation;
4, check the high-pressure water, steam pipes, valves are normal, soaked steam pipe drainage is normal, soot valve before the pressure and superheat is normal;
5, check the radial, circumferential, axial sealing gap, sealing plate bolts are normal;
6, check the rotor top and bottom bearings, gear box oil lubrication oil level to meet the requirements;
7, check the air preheater import and export baffle has been closed;
8, check the fire monitoring device, check the local cabinet to ensure its normal work;
9, check to ensure that the rotor stall alarm device is working properly;
10, check the air preheater reducer, upper and lower bearing running sound is normal;
11, check the drive motor current is normal;
12, check the air preheater air, smoke import and export of temperature is normal.
Heat exchange element soot-blowing:
1, the air preheater normal operation after blowing once every 8 hours, and in strict accordance with the sootblower instructions that ensure that the air preheater resistance to maintain the operating value within the design value, before the shutdown, in the boiler startup process and Soot blowing must be intensified during the low load stage.
2, in order to avoid condensation on the surface of the heat exchange element, the steam should be soothed when the temperature of the heat exchange element is high, so the soot blowing should be selected under the condition that the unit reaches a certain load.
3, in order to ensure that the soot blowing effect, to prevent all the external water into the air preheater, pay attention to the selection of a certain pressure and temperature of the superheated steam to ensure the provision of dry purging medium, soot steam temperature control 120 ℃ ~ 330 ℃ Between the steam nozzle outlet pressure 1.5MPa. Such as the use of steam blowing with water, will cause corrosion of the heat exchanger components.
4, to ensure that the steam pipe condensate does not enter the soot blowers, blowing must be thoroughly effective before the hydrophobic.
Blowing ash water vapor will lead to corrosion of components, air preheater heat exchanger components to increase the adhesion and hardness of the surface so that it can not be removed by steam soot blowing, exacerbating the fouling of heat exchanger components and plug.
5, in the soot blowing process if the cold side temperature is low, should take measures in advance (investment heater or hot air recycling) to improve the cold end of the heat exchanger element wall temperature, to ensure that the air preheater "cold end integrated temperature" Less than the minimum recommended value. (Ie the cold side of the flue gas temperature + air temperature of not less than 150 ℃)
Heat exchanger cleaning:
1, air preheater in the process of running, the resistance is greater than 35%, should stop using high-pressure water cleaning. When the unit is loaded with high pressure water is prohibited to clean the heat exchanger components, because the instantaneous rinse of high pressure water will cause chilling phenomenon of the components, the enamel, the component body caused fatal damage. If necessary, the need to stop after the flushing, high pressure water pressure is not greater than 15 MPa, and heater to open.
2, in the air preheater resistance is greater than 25% of the design value, the use of low pressure water rinse, once the use of low pressure washing, it is necessary to thoroughly clean, or heat transfer surface of the component will form a lump of sediment. Washing water temperature of 5060 ℃ is appropriate, washing is usually carried out under low speed conditions, and the heat exchanger temperature state (than the ambient temperature higher than about 3545 ℃) for washing, low pressure washing effect is better, hot air drying after washing dry .