1156 posts
Burning Question 61
I have two questions: What is the effect of NOx and SOx in controlling the burning zone temperature and what other parameters like kiln torque, kiln inlet oxygen or if anything else affects the kiln operation.
Secondly, how to improve the ventilation in ball mills, as we observe the coating formation on the balls is on the high side.
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1156 posts
Re: Burning
NOx and kiln torque are both good indicators of the temperature in the burning zone of the kiln. This is key to ensuring stable operation and good combination of the clinker. Kiln inlet oxygen is a good indicator of the combustion conditions in the kiln where a small excess of oxygen is necessary to ensure burning in oxidising conditions. SOx rises if there is reductive burning and CO present in the burning zone therefore this reinforces the kiln inlet oxygen measurement.
To improve the ventilation in the ball mill you need to increase the speed of the induced draft fan. However if you are suffering coating of the media this is more likely related to temperature control in the mill. This is a function of the clinker temperature, ventilation and the cooling with water injection.
1156 posts
Burning Question 62
Ours is ILC 5-stage pre-heater kiln with 3300t/day production capacity. Recently we have changed the kiln fuel from fuel oil to 100 per cent coal. The kiln torque in case of fuel oil firing used to vary between 28 and 38 on normal kiln running. After switching the kiln on coal, the torque figure remains between 6 to 11. The litre weight of the clinker remains between 1.35 where as on fuel oil the same varied between 1.22 to 1.28. Otherwise the operational parameters for kiln in both the cases are more or less same.
1156 posts
Re: Burning
The composition of the coal has affected the melt content of your clinker. This is affecting the kiln torque because stickiness in the charge in the kiln has changed and is not climbing the rotating walls of the same extent. This also explains the increased density of the clinker. However, you are not suffering any other operational problems which is a good result with such a major change in operations. Congratulations!