Mixing of secondary air into the flame

The M.A.S. injection system creates single air jets. Between these air jets, zones with low-pressure are created. In this way hot secondary air is drawn strongly into the flame. This provides a quick and homogenous mixing of secondary air with fuel and combustion gases, a rapid ignition, a hot sharp flame, best heat transfer to the clinker bed and excellent burn out conditions.

As Unitherm Cemcon has produced traditional dual channel burners with radial and axial air channels up to end of 1993, we compare the traditional burner with the advanced M.A.S. system.

M.A.S. burner (Multi-jet burner)	Traditional dual channel burner
Outflow of the primary air is divided into 12 to 18 individual air jets	Outflow of the primary air via two coaxial channels (axial air / radial air)
Primary air impulse remains always constant at different flame shapes and the point of design	Primary air impulse reduced with different flame shapes compared to point of design
Internal recirculation zone and recirculation of the hot secondary air, fuel and exhaust gases	Internal recirculation zone mixture and recirculation of primary air, fuel and exhaust gases
The size of the inner recirculation zone remains constant at different flame shapes	The size of the inner recirculation zone varies with different flame shape settings
Primary air flow at the nozzles is swirl free	Primary air flow at the nozzle area has a certain swirl
Flame setting is achieved via a different deflection angles of the air jets. Control range of the mixing zone length is approx. 1:3. Thus it is possible to adjust a very sharp hot flame	Flame setting is achieved via a changing of the swirl number of the primary air. Control range of the mixing zone is approx. 1:15
Primary air supply: 315 mbar of primary air pressure is sufficient to burn even hard burnable fuels	Primary air supply: 400 to 600 mbar of primary air pressure is recommendable