Dr.-Ing. Stefan Vogt

Do counterflow kilns hold the promise
of an energy miracle? (Part 1)

»1 Drawing excerpted from Conrad Dressler‘s patent specification for a double tunnel kiln in the year 1924 [3]

»2 Electric counterflow tunnel kiln by Kerabedarf in Nieder-Ullersdorf,
1938 (from [2])

Author/Autor

»3 Cross section of a counterflow kiln with perforated partition

Author/Autor

»4 Counterflow kiln with forced circulation fans

»5 Temperature curves of counter-travelling flows of gas and product in
a tunnel kiln

»6 Required air-to-brick ratio in exhaust gas of a counterflow kiln as a function of energy losses (postulated: natural gas H with λ = 1.0 as broken line; λ = 1.25 as solid line)

»7 As-found mass flows and temperatures characterizing the air balance in the Grechwitz counterflow kiln [9] (optimized state)

»8 Energy balance of counterflow kiln with free convection (Grechwitz)

»9 Energy balance of a tunnel kiln for backing brick production

The theoretical principles governing the energy consumption of counterflow kilns are explained and compared with the actual performance data of existing counterflow kilns. In addition, the advantages and disadvantages of different types of counterflow kilns are discussed and their energy conservation potentials compared with the energy consumption of fast firing kilns.

1 Introduction

According to research by Böger [2], Carl Emmel was awarded German Imperial Patent No. 13604 on May 1, 1880, for his counterflow kiln. The first reference to a foreign patent found by this author was made by Conrad Dressler on July 1, 1924 [3] concerning a tunnel kiln with two parallel channels through which trains of kiln cars travel in opposite directions (»1). It is not known whether a kiln of the type described was ever actually built.

In the 1930s and ‘40s, Riedhammer, Kerabedarf and Siemens-Schuckert built a number of counterflow kilns, some of which were electrically heated...

Robert Thomas Metall- und Elektrowerke GmbH & Co. KG
www.rotho.de

Issue 5/2018 Dr.-Ing. Stefan Vogt

Do counterflow kilns hold the promise
of an energy miracle? (Part 1)

1 Introduction

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Do counterflow kilns hold the promise of an energy miracle? (Part 2)

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Solid-solid recuperation for increasing the energy efficiency of tunnel kilns

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1 Introduction

ZI 4/2018

ZI 4/2018

Related articles:

Do counterflow kilns hold the promise of an energy miracle? (Part 2)

The solid-solid recuperator – a forced-convection tunnel kiln for higher energy efficiency

Benefits and boundary conditions of fast firing clay building products (Part 2)

Solid-solid recuperation for increasing the energy efficiency of tunnel kilns

Simulation of the firing of ceramic ware Part 1: Understanding the firing process in tunnel kilns