RAW MEAL HOMOGENIZATION AND STORAGE IN CEMENT INDUSTRIES

We were discussing “Cements and its types” and “Material preparation technology in cement manufacturing” in our previous posts. We have also see the concept of cement manufacturing process and its selection in our recent post.

Today we are going to start here one very important topic i.e. raw meal homogenization and storage in cement industries. We will understand the various terminologies and engineering concepts used in cement technology with the help of this category.

Further we will go for discussion of burning technology, firing technology, clinker cooling and grinding, cement packing and dispatch, pollution control and much more facts about cement technology in our next post in this category of cement technology.

Before reading this article, please read following post for better understanding of this post.

Processtechnology of cement manufacturing: Raw grinding plant

Cement manufacturing technology: storage and pre-blending

Raw Meal Homogenizing and Storage:

The final product of the raw grinding plant such as slurry and dry raw meal is essentially to be homogenized effectively due to stringent requirements of the kiln plants i.e. for:

~ Stable operation of the pyro - processing plant for sustained production

~ Quality cement clinker production

Compressed air is used widely for homogenizing the slurry or raw meal. The storage capacity of the section is designed to meet the requirement of the pyro - processing plant for 3 to 4 days.

Slurry Homogenization

Two or more blending silos are used for correcting and homogenizing the slurry. Compressed air is supplied at high pressure for a certain amount of time till the slurry is homogenized as determined by plant laboratory tests. Higher blending effect than dry raw meal can be achieved. The homogenized slurry is then stored in slurry basins provided with mechanical stirring devices and compressed air supply.

For the same capacity of the kiln plant, the investment as well as operating cost is higher than that for dry meal homogenizing.

Dry Raw Meal Homogenization

There are two basic homogenizing processes for dry raw meal i.e. Batch process and continuous process.

In the batch process, at least two pairs of double deck silos, each consisting of a blending silo at the top and a storage silo below are used. Sequence of operation of the silo i.e. filling, blending and storing is made independently.

In continuous process, one or more single deck silo is used and compressed air is used only for the aeration pads for the extraction of the raw meal from the silo. Cylindrical silo with inverted cone design for its bottom is preferred due to low specific energy (electrical) consumption.

The advantages and disadvantages of the these two processes are as mentioned here

- Investment cost for civil work is more in batch -type than continuous - type.

- Energy consumption in compressed air supply for fluidization is much higher in batch type resulting in increased operating cost.

- Blending effect is higher in batch type (1: 12 to 15) as compared to continuous type (1: 8 to 10)

Do you have any suggestions? Please write in comment box.

We will see other topic i.e. Grinding and drying of coal in cement industry in our next post in the category of Steel and cement technology.

I am very thankful to Mr. Subrata Bhaumik, Independent cement consultant, for providing such beautiful information and contents about cement technology.

Mr. Subrata Bhaumik has more than 50 (Fifty) Years (1965 - 2016) of Experience in Cement and other related Industry covering more than 100 assignments in cement plants with capacities ranging from 100 tpd to 10,000 tpd in India and abroad involving visit to 25 countries overseas in connection with work.

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