Lime production experience 4.0

Italian plant engineering contractor QualiCal has designed and built a 150 t/d Synthesis regenerative vertical kiln (PFR – twin shaft burning unit) for Köhler Kalk. The kiln boasts rock-bottom investment and running costs and is capable of turning out quicklime of the highest quality. Digitization was one of the project’s major elements.

1 The calcination process

The calcination of limestone is a chemical process of decomposition in which heat applied to carbonates decomposes them into oxides. Decomposition takes place at a temperature of around 810 °C:

CaCO3 + heat = CaO + CO2

To ensure that the limestone rock decomposes all the way through, the heat of dissociation must be able to penetrate to the core. So, for complete calcination, the surface of the stone must be heated to above 900 °C. The surface temperature, however, should not exceed 1100 – 1150 °C, because that would cause sintering, or dead burning, of the calcined...

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Issue 12/2011

Simulation of lime calcination in PFR kiln – Influence of energy input and lime throughput

This article presents a one-dimensional mathematical model to describe and simulate the lime calcination process in a parallel flow regenerative (PFR) lime shaft kiln. The model comprises ordinary...


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Issue 02/2024

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The current state-of-the-art Benchmark for any proposed new lime-burning process is the PFR kiln. This type of kiln achieves the lowest possible specific thermal-energy consumption. A whole series of...

Issue 04/2012

Simulation of lime calcination in PFR kilns – Influence of source and size of limestone

The previous article presented a one-­dimensional mathematical model to describe and simulate the lime calcination process in a PFR lime shaft kiln [1]. The model was used to calculate the...