Re: bypass ratio
I.Flex:I need to know why bypass ratio decrease when the oxygen in the kiln inlet increases and vise verse.
The kiln inlet O2 determines the volatility of alkalis and sulphur in the kiln gases. The reaction (for potassium) is;-
K2O(g) + SO2(g) + 1/2 O2(g) <---> K2SO4(s)
As can be seen from this equation, excess oxygen promotes the formation of the far less volatile K2SO4. Being less volatile, K2SO4 is more easily able to pass through the burning zone and leave the kiln, locked within the clinker matrix. This proportionately reduces the amount of alkalis and sulphur available to condense on the bypass dust.
Either way, the same amount of alkalis and sulphur are removed. However it is far more beneficial to have sufficient O2 in the kiln inlet to maximize the amount of alkali sulphates in the clinker, and to prevent kiln inlet and lower cyclone buildups.