Chemical agglomeration properties of fine particles immersed in solutions and the reduction in fine particle emission by adding emulsion polymers

• Published in: Fuel processing technology 2018-06, Vol.175, p.44-53
• Main Authors: Zhou, Lei, Yang, Shu-ying, Chen, Wu, Wang, Xiao-bei, Yuan, Zhu-lin, Yang, Lin-jun, Wu, Hao
• Format: Article
• Language: English
• Subjects: Agglomeration; Atomizing; Chemical agglomeration; Droplet diameter; Droplets; Emissions; Emulsion polymerization; Emulsion polymers; Fine particles; Flue gas; Fly ash; Molecular chains; Nozzles; Organic chemistry; Particle emission; Phase Doppler Anemometer; Velocity measurement; Viscosity; Water chemistry; Water soluble polymers
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2018.02.027

To reduce the fine particle concentration in coal-fired flue gas, an emulsion agglomeration agent with excellent atomization performance and low viscosity was applied in a chemical agglomeration experiment. The chemical agglomeration properties of an emulsion polymer and a water-soluble polymer on fine particles were compared and investigated experimentally in this study. In addition, the relationship between the mass concentration and solution viscosity was explored, and the atomization performances of a two-fluid nozzle were also studied. The results showed that when the mass concentration of the agglomeration agent increased, the fly ash particles in the solution became larger; moreover, the final agglomerate diameter and the solution viscosity were related to the polymer molecular weight. According to the phase Doppler anemometry (PDA) experimental results, the median diameter (D50) of the agglomeration solution droplets increased as the mass concentration increased, and the atomization property of the emulsion polymer solution was evidently superior to that of the water-soluble polymer solution. In the experimental facility, chemical agglomeration experiments using four kinds of agglomeration agent were carried out, and they proved that the removal efficiency of fine particles was inversely proportional to the median diameter of the atomized solution droplets. Emulsion polymers can greatly enlarge fine particles and reduce the concentration of the fine particles. The removal efficiency of number concentration was improved by 20–25%. •An emulsion agglomeration agent with good atomization performance is proposed.•The particle size of the final agglomerate increases with increasing molecular weight.•The mass concentration is an important factor influencing the viscosity of the solution.•Increasing the viscosity of the agglomeration solution will enhance the droplet size.•The removal efficiency of fine particles decreases as the diameter of droplets increases.