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