Investigations into the regeneration of rigid ceramic filter candles for hot gas filtration

J. Sitzmann*, J. Markgraf, Calida-Cleantech GmbH, Germany

Due to rising environmental standards hot gas filtration of flue- and process gases at temperatures above 250°C become increasingly economic feasible. Especially, when downstream processes like SCR-catalysis for NOx -treatment require high temperatures, particulate removal at process temperatures is advantageous to avoid additional heating of the gases. This rapidly growing market reflects in the development of the ceramic filter elements, which are now available up to a length of 3 meters, with optional coating for DeNOx-Catalysis. With the manufacturers already aiming to extent the length to 6m for easy replacement of bag filters.

During regeneration of bag filters for operation below 250°C, the filter bag expands. The expansion causes the filter cake to break of. In comparison rigid, ceramic filter elements as applied for hot filtration will not expand, therefore only the developed gas stream against the filtration flow will actually blow of the filter cake. For this reason, the design of a reverse pulse system for rigid ceramic filter candles needs more knowledge about the achieved cleaning pressure as well as the pressure distribution over the length of the filter element.
Calida-Cleantech operates test facilities to investigate into the regeneration behaviour of ceramic filter elements. The filtration test unit can be operated with filter candles up to a length of 3m. The objective of the experimental set-up is to evaluate the correlation of design parameters of the reverse pulse system like tank pressure, tank volume, valve opening time and nozzle diameter to the achieved cleaning forces. The cleaning forces generated during reverse pulse were measured via piezzo-electric fast pressure transducers with a resolution of 0,05 ms. Furthermore, the results of the conventional jet-pulse system were compared with the cleaning forces achieved via a coupled pressure pulse system (CPP-system) as introduced by Mai et al. First results show, that...

Session: G15 - Hot Gas Cleaning
Day: 15 March 2018
Time: 10:45 - 12:00 h

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