Development and Optimisation of Analytical Techniques for Non-Woven Flue Gas Filtration Media

Combustion of solid fuels produces solid and gaseous emissions which are harmful to the environment. Filtration, in combination with additional process such as sorbent injection aim to reduce the concentration of these emissions before being released into the atmosphere. Bag house filtration composes of multiple bags of filtration media that collects the solids from gas streams. In power generation, these units collect fly ash and other solids from the flue gas, depositing them into a hopper for disposal. Industrially new and used filtration media from various sites were examined. Analytical techniques such as air permeability, mass/density, and thickness were used to determine the variation within a defined sample size. Whilst the British Standards were used as the baseline methodology, they required a significantly small surface area for analysis in comparison to surface area of a flue gas filtration bag. When the sample size was increased, results suggested a relationship between the data and the diameter of the bag for air permeability, mass/density, and thickness. In addition, a preliminary longevity study was explored using new and industrially used media. This study used µCT, SEM, air permeability, mass/density, and thickness measurements to illustrate how the media changed once it had reached a predefined end point. Whilst these results are preliminary, the critical evaluation of the data suggested how longevity may be calculated. As the sample size increases, so does the time required to perform analysis. The work presented in this thesis demonstrated the potential variation in a sample and illustrated relationships about the circumference of the bag. These relationships could be investigated without severely impacting the sample turnaround time. This work is being discussed with members of the British Standard Working Group 7 to update their standards to better reflect and understand the potential variation across air permeability, mass/density, and thickness analysis.