Experimental Investigation Of Fine Particle Agglomerator Based On Hydrokinetics Theory

Haze has become an extremely serious environmental problem in China in recent years.Fine ash particles emitted from pulverized-coal（PC）-fired boilers are the most important factor contributed to the haze formation.However,conventional particle-removal devices commonly have a poor efficiency of capturing fine fly ash particles.Particle agglomeration is one of effective technology for controlling the emission of fine ash particles from PC-fired boiler.Multifaceted investigation of hydrokinetic agglomeration technology is presented in the paper.First of all,hydrokinetic forces and inter-particle forces in the process of particle motion in the agglomerator are introduced and the order of magnitude of the hydrokinetic forces and inter-particle forces are respectively compared.Through the force analysis of particles,the mechanism of particle hydrokinetic agglomeration and working principle of the agglomerator are introduced.Secondly,the experimental project,including method and content of experiment,method of measuring and sampling,analysis method of sampled ash particles,of agglomerator are designed.The experimental system,including experimental bed,agglomerator and heat exchanger,are also designed.Experimental research of hydrokinetic agglomeration of fly ash particles is conducted.The disciplines of ash particle agglomeration influenced by the working parameters of flue gas are obtained from the analysis of the experimental results.And the effect of turbulent agglomeration,thermal agglomeration and Brown agglomeration in aerodynamic agglomeration is compared.Finally,the experimental investigation of hydrokinetic agglomerator on a 330 MW PC-fired boiler is designed.The design of the experimental investigation includes the design of the agglomerator for in-situ trial,testing content and tested method,the method of measuring and sampling and analysis methodologies of sampled ash particles.The evaluation methods of the working effect of the agglomerator are introduced.The in-situ trials of hydrokinetic agglomerator on a 330 MW PC-fired boiler are conducted.The results of the in-situ trials show that the PM_2.5 and PM₁₀ are found to decrease 56.2%and 50.6%,hence reducing the overall particle concentration by 26.3 mg/Nm³ at the outlet of the ESP.Also,the mercury concentration of 891.08ng/g obtained in the ash from hoppers of the ESP with the agglomerators is 26.4%higher than that of the ESP without agglomerator.Therefore,the application of hydrokinetic agglomerators is believed to reduce both emissions of fine particles and mercury from the flue gas of PC-fired boilers.