单独的静电除尘器(electrostatic precipitator,ESP)和布袋除尘器均对于0.1-1μm的亚微米颗粒具有较低的除尘效率。采用复合外加条件,即ESP和布袋除尘器串联的紧凑型混合颗粒收集器(compact hybrid particulate collector,COHPC),有望提高可吸入颗粒物的除尘效率。针对一典型300MW机组的ESP,讨论了2种对其进行改造的技术方案,即对ESP本体进行改造和采用COHPAC,对改造前后ESP的除尘过程进行了颗粒群平衡模拟,并对电增强布袋除尘器的非稳态除尘过程进行了数值模拟,从而定量描述可吸入颗粒物在多种外加条件下的非线性和微尺度动力学演变规律。数值模拟结果表明,COHPAC比本体改造前后ESP具有更高的可吸入颗粒物(particulate matter,PM)除尘效率,整体质量和整体数目除尘效率可以达到99%以上。
Individual electrostatic precipitator (ESP) and individual bag filter exhibit low collection efficiency of submicron particles with aerodynamic diameter of 0.1-1μm. The hybrid external conditions, namely, the compact hybrid particulate collector (COHPAC) which is characterized by the combination of electrostatic precipitator and bag filter in series, is capable of updating the collection efficiency of particulate matter (PM). As for an original ESP with a low collection efficiency of PM which was equipped in a typical 300 MW coal-fired boiler, two technique schemes, the ESP retrofit and COHPAC, were discussed. Population balance modeling was carried out against the original and retrofitted ESPs, and the unsteady dynamic filtration of the COHPAC was numerically simulated, in such a way that the nonlinear and micro-scale dynamic evolution of particle size distribution under the hybrid external conditions was quantitatively described. The results of numerical simulation show that the COHPAC, in which the overall number and mass collection efficiency reach to 99%, possesses the higher collection efficiency than the retrofitted ESP and the original ESP.