NTE (NOL-TEC Europe) Steelmaking Plants:

• Lime and Carbon Injection System

In  steel   making   process, they  inject   pulverized  lime   and  carbon  into  EAF furnaces   for   process   reasons   especially   sludge   formation. To   inject   the mentioned material into  the  furnace  under  operation, they  need  pneumatic force.

Lime  and  carbon  injection  system  is actually a pneumatic  conveying  system which  conveys  pulverized  material  from  the  silos  to  injection lances  of  the furnace. This system is comprised of  two  distinct and  independent  parts. The first part conveys material from  outdoor  storage facilities to  daily  bins  inside the  workshop  and  the  other  part  conveys  material  from  daily bins into the furnace.

The main components of the system include:

> Siloes  and  storage facilities in  which all of  provisions for  fluidization and inertization are envisaged. The whole process is under monitoring by means of  sensors  to  evaluate  temperature  and  pressure  of  the  system. In case temperature exceeds a certain limit about combustible material like  carbon, Nitrogen injection facilities will be put  into  action  to  eliminate  combustion threat. The silos are also equipped with level  controlling devices. All  of  silos have  a  top  silo  filter  on  their  roof to mitigate dust emission during silo or transporter  loading  cycles. The  silos  can  be charged both by truck loading device or big bag unloading stations.

> Transporters  whic are pressured vessels equipped with level and pressure sensors. They  receive  material  from  storage  silos  and inject them into the conveying  pipeline.  The  indoor  transporters  which  receive  material  from daily bins are equipped with weighing sensors to inject the right  quantity  of material into the furnace according to the set point defined by the  operator. The  mechanism  is  like  LIW feeder in which the weight of the transporter is measured   periodically   in   time  and  the  feedback  of  the  control  system controls quantity  of  injected  material  commanding  a  proportioning  valve underneath the transporter.

> Conveying lines  which are  equipped  with revolutionary NTE patent named “Air  Assist”. The  function  of  this  system  is  to  balance  pressure  of  certain positions of the conveying line with transporter and in case the pressure drop is considerable, compensates this pressure loss injecting  compressed air into the pipeline. The  advantage  of  this  system is  that  generally  the  conveying pressure reduces compared with the other  technologies and  compressed air consumption  is  saved  considerably.  Furthermore,  the  column  of  material inside the pipeline is broken into several parts with air  packs  in  between. So in the case system stops due to power failure or  any  other reason, it  will  be possible to bring back the system  into o  peration  simply  pushing  the  push button without needing to open the elbows to empty  the  pipeline  manually. This problem is very common in pneumatic conveying lines.

> Control  System  which  consists  of  RIO  cabinets  to collect  field signals to communicate   them   to   the  LCP   panel   under   network   communication protocols like Profibus. As RIO cabinets are  located close to  the  equipment, weighing boards are also mounted inside them. The LCP is equipped with IO and PLC  modules  to  monitor  and  control  the  whole  system. The  control system is normally based on  Siemens  technology  although it is possible  to supply other control systems upon customer’s request.