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Calciner

Process Description

Calcination, also known as de-acidification, describes the expulsion of CO2 from the limestone at approx. 850°C upwards.  This process step takes place in the calciner and in the calcining zone of the rotary kiln. The calciner is usually to be found in the form of a cyclone pre-heating tower (formerly LEPOL kiln). The raw meal is heated in this counter-current heat-exchanger. The energy for the calcination reaction must also be introduced here, or via a burner in an additional pre-calciner. Modern pre-calciners already use up to 100% replacement fuels. 

Gas Application

Oxygen as an oxidising agent can improve burnout and reduce total emissions of CO and VOCs.  

Advantages:

  • Higher adiabatic flame temperature
  • Faster reaction speed
  • Greater gas radiation
  • Earlier ignition and thus better and faster burnout of fuel particles 
  • Reduction of emissions (CO and VOCs)
  • Additional parameters for kiln control (fast and easy to control)
  • Less strain on the induced draft

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. 

  

Oxijet – basic impulse lance inside a calciner

The gas input system must be specific to the type of burner and calciner.  Various nozzles can be used for this purpose: 

  • Messer Oxijet - basic                  Impulse lance for burners or calciners
  • Messer Oxijet - swirl                   Swirling lance for burners or calciners for rapid mixing
  • Messer Oxijet - supersonic         Laval lance for burners or calciner, adjusted to O2 throughput
  • Messer Oxijet - atomising           Atomisation of lowest caloric liquid fuels with oxygen   

Application:

Calciner with in-line-precalciner burner:

  • 1000 Nm³/h O2
  • Reduction of total CO-emissions by a 1/3
  • Reduction in total VOC-emissions from incineration by 2/3