THE YEAR-BOOK OF THE COKE OVEN - Coke Oven Managers ...

2.6 Specifications of Coals Supply:
Specification of coal supplied by Tata Steel for conversion is shown in table 1.
Coal Source Ash V.M. Moisture Coal in Blend
Imported 10 % max. 23.5 %
max.
8 % max (may
go up to 10%
during
monsoon)
50 % or (Semi
Soft - 30 %,
Jellinbah- 20
%)
Captive
(Jamadoba )
17 % max. 24 % max. 9.5 % max
(may go up to
10% during
monsoon)
50 %
Table 1: Specification of coal supplied by Tata Steel for conversion
3. Challenges
Problems were faced with respect to coke quality during initial stage of
conversion of coal to coke through beehive oven route. The CSR of coke which
is one of the vital parameters for coke quality was found varying significantly
from ovens to ovens and even within a beehive oven battery. Also, the CSR
values were low and varying in the range of 35-45. Blast furnace operators
refused to charge such low CSR coke in to the blast furnaces. Therefore,
challenge was taken to improve the CSR of beehive coke to above 60 as well as
its consistency.
As per the agreement between Tata Steel and conversion agent, maximum
allowed moisture in converted beehive coke received at Jamshedpur works was
10%. But, actual beehive coke moisture received at Jamshedpur works was
15.1% (average). The undersize (-10 mm) in coke was approximately 3.55%.
High moisture in beehive coke resulted in loss in coke yield, increased
transportation cost and finally caused increase in blast furnace fuel rate. High
fines in beehive coke resulted in coke yield loss and increased cost of
transportation. Hence, challenge was taken to reduce beehive coke moisture by
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