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

coke handling processes with beehive ovens operators. Written procedures were
also not found for quality assurance activities like sampling, sample preparation
and analysis of coal and coke. With respect to coal handling system, it was
observed that no distinct demarcation was being maintained between various
received coals (Semi Soft / Jamadoba/ HCC (imported hard coking coal) / WB
(west bokaro) and blended coal) in the premises of beehive ovens. Different
types of coal had no nameplates or display board for proper identification.
Various individual coals were dumped haphazardly near the blended coal. Coals
were stored in open areas which resulted in moisture gain during rains. It was
also observed that process was not followed for coal usage based on the
principle of “first in, first out” (FIFO) to avoid usage of weathered coal. Latest
received coals were being utilized first. Crushing fineness of blended coals was
inadequate. Stock management of various coals was poor.
Assessment of old practices of coke quenching and handling system at beehive
coke ovens was carried out. It was observed that the time elapsed between coke
pushing and coal charging was very high and varying. The heat condition of the
battery was poor which resulted in green coke pushing (un-carbonized / partially
carbonized coke). This might led to the weakening of coke and generation of
fines. Leakages through the door were noticed. In some of the ovens, whole
bricks from the door were collapsed before coke pushing. Poor sealing of doors
and opening of oven top covers was found in a number of ovens. Cracks on
walls were also observed. Carbonization time was not being adjusted according
to the coal moisture to get good quality of coke. After pushing from ovens, coke
was not quenched immediately due to unpreparedness of quenching system
which resulted in coke burning. Lots of green pushing was observed because of
poor process control.
It was observed that a single big hosepipe was being utilized for coke quenching
with water. This led to requirement of more volume of water for completing the
coke quenching because single stream of water could not cover entire hot coke
pile at a time. This resulted in high moisture (15-17%) in dispatched coke. High
moisture in coke resulted in sticking of fines on lump coke. It was also noticed
that for coke quenching, uncontrolled and continuous single stage quenching
operation was practiced. Quenching was being done continuously for 15-25
minutes duration. Also, the quenching of coke was practiced without dispersing
the red hot coke pile after the pushing. This caused inadequate quenching of hot
coke inside the pile and restricted removal of fines. Velocity of water in single
hosepipe was not sufficient to flush out the fines. Other observations were made
6