Purefrax® Hot Gas Filters (HGFs), also known as Ceramic Candles, are used for high temperature dust filtration and emission control. Where traditional filter bags can only be used up to temperatures of approximately 260°C, HGFs are typically used for dust filtration in the 300-550°C range with the possibility of use up to 900°C. Commonly, HGFs are selected to replace Electrostatic Precipitators and Cyclones, particularly for their greater filtration efficiency and capacity of high temperature operation.

Key Drivers for High-Performance Hot Gas Filter Adoption:

• High‑temperature operation for heat‑recovery.
• Expanding high temperature applications (e.g. Gasification).
• Use of catalyst for removal of harmful gases.

However, there are certain applications where the brittle ceramic material properties of standard HGFs can be problematic. Particularly in earthquake-prone regions but also heavy industrial applications where there are additional stresses or movement.

For example, the use of HGFs in facilities such as glass manufacturing is a well-accepted technology, but when we include the risk of earthquakes and the consequential furnace shutdown, there can be reluctance to use this technology. In cases like these, filter bags are adopted as a compromise. They are made of flexible fabric substrate and resilient to tensile and shear stress, however they can only be used in lower temperatures.

Enabling safe and reliable use of HGFs in environments where ceramic filters have traditionally been a barrier has been one of Alkegen’s primary research and development projects. Today, we are able to share our innovations in this area, announcing the introduction of our new reinforced HGFs, designed to enhance resilience, reliability and performance of HGFs in extreme environments.

The Innovation

The majority of HGF breakages in applications occur at the flange section. This is where the HGF element is subject to the most force, as the flange supports the weight of the whole filter (approximately 10kg for a 3m piece). Alkegen’s new...