CFB boiler supporting a large high-pressure fan in the first China-made features and trends
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Abstract: The large-scale circulating fluidized bed boiler led to the development of the domestic manufacturing sector, the development of auxiliary facilities so that the CFB boiler supporting high-pressure fan in the first home-made step by step. This article describes the home-made high-pressure fan in the first manufacturing technology and to analyze the characteristics of the domestic trend.
Key words: CFB boiler; the first high-pressure fan; domestic
Key words: TK223.26 Document code: B
 
Large-scale circulating fluidized bed boiler led to the development of the domestic manufacturing sector, the development of auxiliary facilities so that the CFB boiler auxiliary facilities of the main high-pressure fan in the first (back to the material flow of high pressure air, cold residue of high pressure air flow, a fan) made step by step . At present, China-made high pressure air has been successful in supporting 410t/h-460t/h large-scale circulating fluidized bed (CFB) power plant boiler. As the circulating fluidized bed boiler furnace with a large number of materials in circulation, so air supply system to overcome the larger resistance circulating fluidized bed boiler so that the fan support was significantly higher than that of the head with pulverized coal capacity corresponding to the fans , In particular, was a fan. Because it has to overcome the bottom plate of the cloth wind resistance, as well as the need for the flow of material power. If the 440t / h circulating fluidized bed boiler pressure of a fan in general as much as more than 24kPa, high-pressure stream of fans (Roots blower) up to the general pressure for more than 58kPa. As the circulating fluidized bed boiler system to ensure fans are safe and stable operation of the boiler of the most important accessory equipment, so fans in the design and manufacturing process, the reliability of the domestic companies have been in the first place. Domestic companies a detailed analysis of circulating fluidized bed boiler system and the smoke wind flow fan of the technical requirements of foreign countries have opted for the production of 100-year-old fan of the company as a technology partner to learn from their successful experiences.
First, domestic companies to develop a fan of the CFB boiler technology characteristics
     1. High-pressure fan for the first time reliable and economic operation. Choice of advanced aerodynamic model class, and "tailor" counterparts in the design, so as to ensure maximum air pressure up to 30kPa, the largest flow of up to 200 000m3 / h, the highest efficiency of the fan up to 86%.
     2. Well-designed, reliable, and stable operation. Taken in the design of a number of quality assurance and reliability.
(1) finite element theory, analysis, calculation of impeller stress and strain, natural frequency and so on; (2) selection of high-strength materials, large enough to guarantee the safety factor to prevent fatigue damage; (3) of the shaft vibration in response to the calculation, Calculations take into film stiffness and rigidity of the base to ensure the stability of the rotor; (4) 410t / h circulating fluidized bed boiler for more than a fan bearings using sliding bearings, and increased the radial and axial bearing capacity and extend the service life.
     3. In the manufacture of a number of assurances to take to improve the quality and reliability.
     (1) high-precision dynamic balance; (2) advanced means of welding. Such as submerged arc welding and so on; (3) strictly reliable weld inspection: X-ray (on the seam), coloring, Magnetic Particle Testing (welding every angle).
     Second, the domestic companies to develop the CFB boiler technology characteristics of the Roots-feng
     L, 3R series Roots blower fan is in the national joint design and manufacture of technology based on internal company set nearly 40 years of experience in manufacturing Roots blower, foreign technology long after the modified design of the production of a high-energy, low-noise New Roots blower, which has been widely used in all walks of life. Several domestic companies design and production of sophisticated product mix, the fine materials, manufacture of high precision, low noise, long life, to facilitate the use of maintenance products in strict accordance with national standard production, high-precision machining equipment. Its characteristics are as follows.
     1. Impeller fan-line using the new composite structure of the face to the world's advanced level of high-precision CNC machining center impeller processing, to ensure good value gap, which leaked a small amount of low-temperature, greatly enhanced the efficiency of the air volume, reaching a high Energy-saving effect. At the same time reducing noise played an obvious role.
     2. High pressure air using water-cooled wall panels, the lower the air temperature gas within 8-10 ℃, increased gas density, an increase of the quality of volume, has received a certain energy-saving effect of long-term bearing on the lower temperature operation, to extend the service life of bearings .
     3. Fans use PTFE composite seal, seal wear ring, seal to be effective, easy to replace.
     4. Case, the key parts, such as wall panels using high-intensity HT250 gray cast iron, to ensure that the stiffness of the fan, a fan to improve the whole life.
     5. 40CrMo gear used to create high-quality steel, the tooth surface carburization use or deal with nitrogen, up to the surface hardness of HRC56-58, accuracy of up to 5 to ensure that the service life of gear. Gears, bearings used splash lubrication, as a result of lubricants to overcome the broken oil pump failure and damage to the defective fan. Were the words used gear tooth group, the elimination of air operations generated axial thrust, to extend the service life of bearings. Gear wheel and axle with 1:50 taper for the gear assembly and the demolition to ensure the reliability of the fan running, security.
6. Fan out the use of progress under the intake and exhaust means to overcome as a result of the progress of the exhaust gas generated by the pulse of fan vibration. (As a result of progress under the pulse of the gas produced by vibration of the ground with a vertical direction, the direction of amplitude base was spread on the ground in line with the direction of gravity, it was on the ground to absorb vibration, the pulse of gas to overcome the fan caused by vibration)
Third, the conclusions
     To sum up, the first high-pressure fan's domestic manufacturing capability and has a very mature technology, product quality has reached internationally advanced levels. Such fan in the boiler on the application of domestic trends will be strong.