气脉冲除灰器工作机理研究(英文)

STUDY ON THE WORK MECHANISM OF GAS PULSE ASH REMOVER

中国电站锅炉燃用大量的未经洗选的劣质煤,导致严重的锅炉积灰问题,尤其是200~300 MW 的大型锅炉的回转式空气预热器堵灰更加严重.积灰不仅使锅炉热效率下降,而且堵塞烟气流道,影响了锅炉的正常运行.已有的蒸汽吹灰、声波除灰都有较大的局限性.根据我国国情开发出了燃烧气脉冲除灰技术,并在大型电站锅炉应用取得了很好的效果.为了理解气脉冲除灰的工作过程,掌握运行规律,解释应用中出现的问题,以提高技术水平和开发新产品,尚需对气脉冲除灰的燃烧和除灰过程做更深入的研究.该文主要研究了燃料种类,燃料空气比和湍流产生装置对火焰传播速度和压力脉冲峰值的影响,分析了这些参数对除灰能力的影响.这些实验分析结果对实际应用有指导作用.

Chinese power plants burn a large amount of high-ash coal without washing, so the fouling problems areoften serious, especially in the rear portion of the flue gaspassage. For instance, the rotary air preheaters are often fouled up so badly that the furnace has to be stopped for mechanical cleaning of the gas passages. The ash deposits cause lowering of heat transfer capacity and rise in flow resistance, resulting in reduction of output and boiler efficiency. Ordinary steam jetblowers and ultra-sonic or infra-sonic devices are not tooeffective against the hard deposits. The gas-explosion sootremover has been used in some Ukrainian power plants. We have developed similar apparatus and applied it to the airpreheaters of 200~300MW power plants with good results.The combustion process in such devices has been studied in our laboratory. The device consists of a combustion chamber for premixed fuel and air and output tube with openings for the gas jet pulse. The pressure rise and turbulent flame propagation in the prototype and a scaled-down model have been measured with various fuel/air ratios and turbulence-generating setups as experimental parameter. It was found that all these parameters had important effects on the pressure pulse shape. This papermainly gives results of the laboratory study, but also brieflydescribes the results of practical application.