233 posts
TimePosted 23/11/2010 03:12:01
xxxx says

### coal savings

I have hot air source from grate cooler at 250 degree @ 190000 m3/hr. I have a ball mill with auxiliary furnace whose tph is 9 tph with coal input moisture of 10% . The fine coal moisture is 1 %. CV of coal is 7000 kcal / kg coal. How can I calculate the saving of coal if i use this hot air & stop the auxiliary furnace? raj

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41 posts
TimePosted 24/11/2010 06:45:27

### Re: coal savings

1 What's the landing cost of 7000 kcal coal ?

2  9 tph. Is this the capacity of coal mill or auxiliary furnance? if it is coal mill capacity any do you have any rough figure of how much caol presently you are consming for HAG?

138 posts
TimePosted 24/11/2010 07:04:40
lalbatros says

### Re: coal savings

xxxx,

It needs 58.5 GJ  to heat 190000 Nm³  from 20°C to 250°C .
If your coal heat value is 27 GJ/t , 58.5 GJ represent 2.17 t coal.
(did you mean Nm³ or actual m³ in your post ?)

However, in principle, it is not possible to answer your question without knowing more about the milling/drying plant you are considering. See this thread .

also do not understand your question very well. What are these 9 tph of coal? Are these the quantity of coal you burn in the dryer, or is it the quantity of coal you need to dry ? Ideally, you should better include a drawing in your post.

It is quite possible that 190000 Nm³/h is more than what you need to burn the coal you need for drying purpose. To burn 1 ton of coal, you need (stoechiometrically) typically 8500 Nm³ of air or 16000 Nm³ for 10%O2 in the exhaust.
Finally, note that using hot air directly to dry coal might be very dangerous.

Lal