PROCESS DESCRIPTION

The cupola furnace has a special significance for the production of cast iron. Over the decades a great deal of development work has been carried out to optimise melting performance and costs. Scrap pig iron, recycled material and aggregates are loaded into the oven from the top and pre-heated on their way to the melting zone. Melt and slag is separated from each other and continuously or discontinuously tapped off.  

Energy for the melting process in the cupola furnace, with the exception of the cokeless cupola furnace, is created through the combustion of coke. The oxygen-enriched air necessary for the process is fed into the combustion zone via wind nozzles.  

The combustion zone is covered by the melting zone, further creating a reduction zone. The use of oxygen is particularly effective when the feed system used allows it to penetrate deeply into the coke bed. This can be attained through addition of oxygen at supersonic speeds. The aim is to achieve a uniform temperature increase and an even melting of the feed over the entire furnace cross-section without additional wear to the refractory material.  

Advantages:

• Reduction in coke rate
• Increase in performance
• Higher tapping temperature
• Faster reaction speeds
• Greater flexibility
• Increased temperature in the melt zone
• Even temperature distribution over the shaft cross-section
• Lower production costs
• Lower emissions

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.

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. There is communication between feed and furnace controls.

It is important that special rapid-switching valves are mounted as close as possible to the lances in order to provide supersonic speed during each phase of oxygen input. With controlled oxygen input the oxygen volume can be adjusted as desired for the melting performance. In addition to all its process technology advantages, the system, with its well thought-out simple construction, requires little maintenance, is easy to assemble and operate and has low investment costs with a long service life. The fine-tuning of the regulated frequency is carried out during on-site commissioning; the optimised parameters are stored and can be called-up for each product and/or melting performance.   

Oxipyr – Burner Technology

Oxipyr-burners are used as a back-up to superheat the melt in forehearths, which are connected downstream of the cupola furnace. Oxipyr-burners shorten the cold start time of cupola 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