Case Studies:
Fabric Filter


A small coal fired power station required a better solution for their current installation, due to local community pressure and tighter emissions regulations. They needed to have the ability to improve emission levels if regulations changed further, and for work to be completed in a limited shutdown window.
Through an optimised process design (with built-in extra capacity for future lower regulatory levels) and working with the customer in the available shutdown period, a new fabric filter was retrofitted from the existing ESP shell casing. The existing casing was analysed for structural integrity for the new operation to ensure it could hold the extra dead mass throughout its operation. The material handling system was analysed for extra load capacity generated from the filtering process.
The change in technology resulted in emission reduction to current regulations of 10μm and further, to allow for possible future changes. In addition, the OPEX cost (both short and long term) returned the CAPEX cost of the retrofit earlier than estimated.


A mineral sands facility’s overall plant throughput capacity increased, which resulted in operating plant performance issues. Their existing fabric filter installation was experiencing high pressure drops and poor filtration collection and a major retrofit upgrade was not possible.
MAIRSTech conducted an engineering review of the system and flow and CFD analysis of the current setup (as limited information was available of their design). It demonstrated that the current allocation and casing geometry was sufficient for the flow rate, but the current filter media was unsuitable. An alternative cloth material was selected for the plant’s operation.
The enhanced air-to-cloth ratio (A/C), together with an adjustable pulse cleaning rate and control system, improved differential pressure drop across the system. The result is lessened filter bag replacement and a more stable continuous automated operating system, which requires minimal operator interaction.