SCR脱硝装置大颗粒灰拦截技术试验研究

Experimental Study on the Technology of Large Particle Ash Interception for SCR De-NO_x Equipment

针对部分SCR烟气脱硝装置运行中发生的较为严重的大颗粒灰堵塞催化剂问题,采用冷态物理模型试验予以研究,分析了大颗粒灰拦截网的开孔形状、外形结构与安装位置对拦灰效率与系统阻力的影响,并对灰斗、导流、拦截网相结合的多个方案进行比较。研究结果表明:拦截网阻力与开孔率的三次方成反比;对于拦截网阻力和拦灰效率,拦截网开长条形孔优于开正六边形孔和开正方形孔;屋脊式和平板式拦截网的阻力、拦灰效果基本相同;在省煤器出口采用导流挡板+深灰斗+低拦灰网/挡板方案的大颗粒灰拦截效果最佳,其拦截效率可达95%以上,在SCR入口竖直烟道设置灰斗和折线形后墙可进一步提升拦灰效果。

To solve the problem of LPA(Large Particle Ash)plugging in the SCR de-NOx equipment,the study on the technology of LPA interception is performed with the usage of the physical model based experiments.The effects of the hole pattern,the external structure and the mounting position of the LPA screen on its ash removal efficiency and the system drag force are analyzed.Multiple combination schemes of the dust hopper,the deflector and the LPA screen are compared for the best technical solution.The experimental results demonstrate that the ash removal efficiency of the LPA screen with rectangular opening is better than that with square or hexagonal opening.The drag force of the LPA screen varies inversely to the third power of the opening ratio.There is no obvious difference between the pleated and flat LPA screens in terms of the ash removal efficiency and the drag force.It is observed that the ash removal efficiency of the combination scheme of the deflector,the deep dust hopper and the low LPA screen is more than 95%when they are installed in the outlet of the economizer.The ash removal efficiency can be further improved when another dust hopper and a broken-line back wall are installed in the inlet of the vertical flue.