旋流煤粉燃烧第四类稳燃技术

将国内外旋流燃烧器现有的稳燃措施根据其稳燃原理分为3类.分类分析现有稳燃措施不能适应低挥发分煤稳燃的原因和存在的问题,分析得出:扩口、扩流锥、浓淡燃烧、齿环稳燃器等稳燃措施都没有考虑煤粉气流进入炉膛后与高温烟气迅速混合问题.在这些稳燃措施的流场中,煤粉气流进入炉膛,除脉动外,首先沿回流区外缘流动,向外扩张,与二次风混合过早,而并不迅速与热烟气混合;煤粉气流与高温烟气的混合动力为二者之间的横向湍流脉动,混合强度弱.因此,对于低挥发分煤不能起到良好的稳燃作用.提出了第4类稳燃技术花瓣稳燃器,该技术充分考虑了煤粉气流与高温烟气间的掺混速度和前期掺混强度.花瓣稳燃器能够在其背流面形成轴向和径向多种回流区,使得煤粉颗粒与高温烟气间的混合动力除横向湍流脉动外还有宏观对流混合,加大了二者之间的热质交换强度.

Fourth technology of combustion stability for swirl combustion

The stable combustion measure of existing swirl burner are divided into three categories according to their steady combustion principles.Respectively analyzed the reasons and problems of existing measures are hard to burnt low volatile coal fuel.The results show that expanding mouth,expanding flow cone, shading burning and teeth central steady combustion devices are ignored the rapid mixing of the recirculated flue gas with the pulverized coal-primary air mixture.Entering the furnace the primary air-pulverized coal flow moves near the boundary of the central recirculation zone(CRZ),whereas the recirculated flue gas at the boundary moves at the same direction parallel with the pulverized coalprimary air flow.The first zone extends along the back flow of outward expansion,and second wind mixed early,rather than rapidly mixed with hot gases;air-pulverized coal currents and the high-temperature gases for hybrid between horizontal turbulence times,mixed intensity weak.For low-volatile coal can not play a good solid sub-lighted.The Fourth technology that Petal flame stabilizer(PFS) put forward in this paper fully considers the rapid mixing and the intensification between the pulverized coal-air flow and the recirculation high temperature gas.The flow pattern of PFS in the near burner flame consists of many kinds of stable recirculation zones such as radial and axial recirculation.Petals steady flow of fuel vehicles to its back side and radial formation must return multiple zones with high-temperature gas-particle makes air-pulverized coal flow the hybrid character of a microscopic,horizontal turbulence mixed convection,and increased quality exchange between hot intensity.