Goodmorning again;
In grate cooler, why the speed of second grate should be more than the speed of first grate although the same quantity of clinker pass from first to second grate? Since two week the speed of grate 1 and 2 is exactly the same (due to some instrument problem) and till now we don't face any problem. Any command?
saprina
Dear Saprina,
We supplied almost 2.85kg air/Kg.Cl. in a standard grate cooler to cool clinker and out of 2.85kg air/Kg.Cl only 1.121kg air/kg Cl. will be required for combustion air, rest excess hot air vented through cooler stack which is heat loss to atmosphere.Normally first grate is coming in cooler heat recuperation zone.For achieving higher heat recuperation efficiency and heat economy point of view we maintain higher clinker bed height in first grate than second grate.We don't need higher clinker bed height in second grate so second grate speed is kept slightly higher than the first grate.I do hope I have answered your query.
Regards,
R.M.Sahu,
India
Additionally, if the grates are on same level, than there is also a mechanical reason. Clinker bed depth should decrease from grate 1 to 2. Otherwise, grate 1 will have to "push" the clinker "against" grate 2. This would increase mechanical stress and risk of failure over time.
If stroke length is the same, grate 2 should therefore run a little bit faster than grate 1.
For a short period (a few weeks) I would not expect much problems however.