Regenerative Burners
The use of regenerative burners in Aluminium melting furnaces has become the norm, with around 80% of new furnaces being commissioned, and many others being upgraded, to use this energy saving technology.
Regeneration uses a pair of burners that alternate firing cycles whilst recovering and storing the waste heat from exhaust gasses. The exhaust gasses are passed through a bed of media balls which trap the heat, using it to preheat the air to temperatures of around 300oF - 500oF before the burner is ignited, continuing the cycle.
Regenerative burners are extremely effective, utilising waste heat to reduce fuel consumption by up to 50%.
Bed Changes
The problem then arises that the media balls heat retention properties will decrease as contaminates from the exhausted gasses build up around the balls restricting air flow and reducing heat transfer. This occurs more often when processing scrap with higher contamination levels resulting in increased periodic changes of the media beds.
Media bed changes can be time consuming, messy, and need to be scheduled during burner downtime.
Improving the process
Air Cannon technology improves performance of the media beds by automatically delivering a bust of air into each bed at recurrent intervals between burner shut offs and transfer of exhausted gasses, agitating bed media allowing any contaminates to fall away. The fine dust that causes blockages is blown through the system rather than being allowed to build up, therefore reducing the period between media bed changes.
The system
Air Cannons can be fitted to existing regen beds and integrated into existing control systems. Using pre-existing compressed air lines, the cannons are usually installed between burner pairs, by modifying each burner bed to include an internal distribution pipe for the air to be released into the bed under operation.
Case Study
This technology was installed on a Mechatherm X-Series furnace operating in North America. The system was set up for 90% of the exhaust gasses to pass through the regen beds and 10% through the furnace flue. Before the installation there was a requirement to change the media beds every 4 days. This requirement was driven by the beds blocking with a fine dust, causing the air flow through the beds to reduce, meaning the 90% to 10% ratio would start to change. Since the installation of the system the requirement to change the media beds has reduced to just once a month, initiated during regular maintenance.
Mechatherm Services
Mechatherm International Limited is licenced to install Air Cannon technology and offers a broad range of upgrades and servicing plans through our dedicated in-house Services division.
