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Shaft Furnace

Process Description

In the shaft furnace the feed material flows from the top to the bottom of a perpendicularly positioned oven chamber. The energy for the melting process is generated by the combustion of coke and combustible components of the feed material (for example, plastics). The air necessary for combustion is fed into the melting zone. Shaft furnaces are used for the manufacture of primary lead and for lead recycling. During primary lead manufacture, the lead oxide resulting from the roasting process is reduced to metallic lead in the shaft furnace with the help of coke. When recycling batteries, the batteries are separated from the accompanying acid, roughly shredded with other scrap lead and discontinuously fed with additives to the shaft furnace for melting.

Gas Application

The combustion air necessary for the process is enriched with oxygen and introduced into the region of the melting zone via tuyeres or wind nozzles. To ensure the predetermined oxygen content in the combustion air, the controls of the oxygen supply communicate with the furnace controls.  Messer’s Oxijet- supersonic lances, which feed the oxygen directly into the furnace, are used. The controlled Oxijet process was developed in order to be able to accurately control oxygen levels even at supersonic entry.

Oxygen enrichment at lead shaft furnace

Oxygen enrichment creates the following advantages when used with a shaft furnace: 

  • Reduction in coke rate
  • Improved performance 
  • Reduces post-combustion burden
  • Faster reaction speeds
  • Greater flexibility
  • Raised temperatures in the melting zone 
  • Even temperature distribution across the shaft cross-section 
  • Lower production costs
  • Lower emissions

The table shows possible increases in performance for one application through the addition of oxygen to a shaft furnace.

130 t/d Shaft furnace

with O2

O2-content in furnace wind

23-25%

Increase in performance

10%

Increase in performance through addition of oxygen to shaft furnace. 

Oxijet-technology has been installed over 40 times in cupola and shaft furnaces, with 2 of these in the lead industry. 

Messer-Solution

In addition to the gases required for your process, Messer offers a variety of equipment for its optimisation under the brand names Oxipyr and Oxijet. 

In order to select the optimum system, experts from Messer first carry out a comprehensive process analysis. Following calculations and basic engineering, suggestions are made for optimisation and further procedures.

Controlled (Pulsating) Oxijet

Oxygen is introduced directly into the furnace via lances with the oxygen exit velocity in the supersonic range.  The lava lances used only generate the required impulse when there is a defined design point. Pulsation guarantees consistent oxygen content in the air/oxygen mixture. 

Oxipyr – Burner Technology

Oxipyr-burners shorten the cold start time of shaft furnaces. Oxipyr-burners are used in combination with dust feed systems. Dust feed lances and high momentum burners together form one unit.  

Advantages:

  • Higher combustion efficiency
  • Higher melting rate
  • Faster heating-up times
  • Lower fuel consumption
  • Higher processing temperatures possible
  • Faster reaction speeds
  • Lower exhaust gas levels
  • Less dust
  • Lower emissions
  • Lower production costs      

The characteristics of the burner types are multi-faceted and range from low to high momentum burners, oxyfuel to oxygen/air mixing burners and burners for different fuels or fuel combinations. The systems are controlled manually, semi- or fully automatically following compositions or temperature.

Oxipyr

Fuel

 

Burner protection

Flame

Burner Technology

gas

liquid

solid

low NOx

refractory material

traversing devices

cooling

monitoring

ignition

Oxipyr – P

X

 

 

 

X

X

X

X

X

Oxipyr – F

X

X

X

X

X

X

X

X

X

Oxipyr – Flex

X

X

X

X

X

X

X

X

X

Oxipyr – Air

X

X

X

X

X

X

X

X

X