1156 posts
Burning Question 85
I am working on a project for my university studying the different technologies used in the cement production process from different companies, and I would like to know if any corporation has already constructed its process with a fluidised bed cement kiln for commercial operation and could reach acceptable efficiency. Also, I am researching for the system with most number of steps at the preheater, and the performance of the process compared to other ones.
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1156 posts
Re: Burning
I am not aware of any commercial operations using fluidised bed for industrial cement clinker production. There are pilot and research installations but not of commercial capacity. There are number of kilns with six-stage preheaters. This brings the exhaust gas temperature down to less than 300 degrees Celcius. However, the most economic number of preheater stages is usually five as increased capital costs for six stages cannot be recovered by the energy savings. A company might choose a six-stage preheater if there is a shortage of water for exhaust gas cooling and conditioning. Therefore most of the existing six-stage preheater kilns are in desert environments.
1156 posts
Burning Question 86
We're suffering from brown clinker. As the results of microscopic analyses, there surely should be reducing condition in the burning of the kiln. So we increased the cooling air flow into the kiln to supply sufficient oxygen. It's getting better but we still have brown clinker. We can't increase the cooling air rate anymore because we already operated the exhaust fan with fully opened condition. So we're considering reducing the coal flow rate. It means clinker production should be decreased. What's the next methods we can do except reduction of throughput production to avoid the brown clinker.
1156 posts
Re: Burning
It sounds to me that you must have combustion problems. I recommend that you should contact specialists and pay for a combustion audit. This will be the best way to find the solution. You might try increasing the primary air flow of the burner to maximum, or reducing the secondary air temperature by running the cooler grate with a lower under-grate pressure setpoint.