We regulate our raw material pile at 105-110 lsf. However the lsf of the raw mill's sample becomes 85-90. How can we have such a large difference?

There might be a problem in the sampling station. More likely you have a problem of segregation of the material. This is most likely when you are reclaiming the end-cones of the pile or in the intermediate feed bin between the pile and the raw mill. One solution is to add the end-cone to the next pile rather than sending it to the raw mill. The intermediate bin should be kept at a high level by setting the reclaimer start signal to a high bin level.

I want to know about calculation mathods of gas & material flow in preheater, pc, kiln, cooler. Further, can you advise why we are getting brown clinker problem in our 2000tpd off-line calciner kiln from which we are recently producing 2500tpd while having 90-91 LSF, 2.26 SM, 1.4 AM.& kiln feed residue up to 22 per cent. How we can improve our clinker quality?

The calculation of gas and material flow in the preheater relies on the principles of stoichoimetry (to assess the combustion gas products from the fuel) and the conservation of mass. In principle what goes into the kiln must come out somewhere and will allow you to prepare a mass balance for the kiln. With regard to the brown clinker you are producing this is most probably caused by having reducing burning conditions in the burning zone of the kiln. This is very bad for clinker quality and fuel efficiency of the kiln. Almost certainly the problem is with the kiln burner and might be solved by adjustment. You must be sure that you maintain at least one per cent oxygen at the kiln inlet.