Page 7 - MESCO Newsline 10th Edition 2018
P. 7

MESCO Newsline

                                          Know Your Plant


                                             DRI  (MESCO STEEL -II)
           M         aithan Ispat Ltd (A Unit Of Mesco Steel)   Temperature  and  process  control  in  the  kiln  are

                                                               carried out by installing suitable no. of air injection
                     is  one  of  the  leading  manufacturer  of
                                                               tubes  spaced  evenly  along  the  kiln  length.  The
                     Directly Reduced Iron (DRI), Steel Billets
                     and Reinforcement bars in India as well   product (DRI) is discharged from the kiln at about
           as  International  standard  specifications.  Maithan   1000°C to a rotary cooler. The cooler is a horizontal
           Ispat  Ltd  was  established  in  2004  and  located  in   revolving  cylinder  of  appropriate  size.  The  DRI  is
           Kalinga  Nagar  Industrial  Complex,  Jajpur-Road   cooled indirectly by water spray on the cooler upper
           (Odisha).  Back-up  Facilities  for  Heavy  Section   surface. Solids discharged to the cooler through an
                                                               enclosed chute are cooled to about 100°C. without
           /Billet & Reinforcement Steel Bar
                                                               air contact. The product is screened to remove the
           Product Capacity                                    plus  25mm  DRI.  The  undersize  –  a  mix  of  DRI,
           Annual DRI production capacity is 210,000 MT with   Dolochar and coal ash are screened into +/- 5mm
           2 X 350 MTPD rotary kilns                           fractions. Each fraction passes through a magnetic
                                                               separator.  The  non-magnetic  portion  of  –  5mm
           Sponge Iron Making Process                          fraction  mostly  spent  lime,  ash  and  fine  char  is
           The process of sponge iron manufacturing involves   discarded.
           removal  of  oxygen  from  iron  ore.  When  that   The flue gases then pass through an after burning
           happens, the departing oxygen causes micro pores    chamber where un-burnt combustibles are burnt by
           in  the  ore  body,  turning  it  porous.  When  the   blowing  excess  air.  The  temperature  of  the  after
           eventual product is observed under a microscope, it   burner  chamber,  at  times,  is  controlled  by  water
           resembles  a  honeycomb  structure,  which  looks   sprays.  The  burnt  gases  then  pass  through  a
           spongy in texture. Hence the name is sponge iron.   pollution  control  equipment  namely  ESP  where
           As part of the reduction process, there are several   balance dust particles are separated. Then the gas is
           endothermic as well as exothermic reactions are     let off into the atmosphere through stack via ID fan.
           taking  place  inside  the  kiln.  3Fe2O3+Co→       Raw Material handling and Preparation
                                                                      Crushing and screening operation are being
                                                               (a)
           2Fe3O4+Co2,  Fe3O4+Co→ 3FeO+Co2,  FeO+C→                   carried out in enclosed area. Centralized
           Fe+Co.
                                                                      de-dusting facility
                                                               (b)    Work area including the roads surrounding
           Process Technology                                         the plant are being asphalted or concreted.
                                                                      In the wet system, water sprays/ sprinklers
                                                                      are being provided at the
                                                               following strategic locations for dust suppression
                                                               during raw material transfer.
                                                               Equipments
                                                                       Rotary  Kiln,  a  cylindrical  vessel,  inclined
                                                               slightly to the horizontal as in Figure which is rotated
                                                               slowly about its axis. The material to be processed is
                                                               fed into the upper end of the cylinder. As the kiln
                                                               rotates,  material  gradually  moves  down  towards
                                                               the lower end, and may undergo a certain amount
                                                               of stirring and mixing. Hot gases pass along the kiln,
                                                               sometimes  in  the  same  direction  as  the  process
                                                               material (co-current),  but  usually  in  the  opposite
                                                               direction (counter-current). The hot gases may be
           Generally in any sponge iron process, the coal and   generated  in  an  external  furnace,  or  may  be
           iron  ore  are  metered  into  the  high  end  of  the   generated by a flame inside the kiln. Such a flame is
           inclined kiln. A portion of the coal is also injected   projected  from  a  burner-pipe  (or  "firing  pipe")
           pneumatically from the discharge end of the kiln.   which acts like a large Bunsen burner.
           The burden first passes through a pre-heating zone   Important Equipments/Machineries
           where  coal  de-volatilization  takes  place  and  iron   Kiln Shell/Refractory Lining/Tyres and Rollers/Drive
           ore  is  heated  to  pre-heating  temperature  for   Gear/ Rotary air lock feeder/Lobe
           reduction.                                          Compressor/Coal Throw Pipe/ Air
                                                               Tubes/ESP's/Feed Tube/ Air Tube

           Winners make a habit of manufacturing their own positive expectations in advance of the event       05
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