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.

For switching to natural gas you need to conduct a combustion audit with a specialised company. I would recommend Kiln Flame Systems (KFS) or Fuel Combustion Technology (FCT). Natural gas is not normally stored. It is piped to your factory and you you draw the gas you need through a flow control valve. It is likely that your specific fuel consumption will rise due to:
(1) the increased volume of combustion products associated with natural gas compared to coal
(2) the lack of ash in coal, and
(3) the lower heat flux generated by a natural gas flame.

Our kiln is a 1800tpd coal fired SP kiln with a specific fuel consumption of 850 Kcals/kg clinker. For switching over to natural gas firing I require the following details.
(1) Burner system and firing arrangement required
(2) Storage capacity and storage system required for storing the natural gas.
(3) Is there any change in the specific fuel consumption?

Oxygen enrichment of the combustion of a cement kiln is useful because it reduces the volume of the exhaust gases freeing additional capacity in the fan to produce additional output. The oxygen is required for the combustion in the cement kiln. The amount of oxygen required depends on the capacity and process of the cement kiln. It is about 120 tonnes per day for a 1 million tonne per year kiln.