Hansa cocking plant - Stiftung Industriedenkmalpflege und ...

From coal to coke –
a trip through the production
process in a coking plant
What is a coking plant – a brief introduction
In a coking plant coal is loaded into hermetically sealed chambers and
heated to high temperatures in coking ovens arranged in batteries of several
dozen narrow chambers. The coal is then baked in the ovens for around
twenty hours at over 1000 degrees Celsius and the so-called “volatile materials”
are drawn off. This process results in coke .Because of its higher carbon
content, its purity and its calorific solidity coke is a more valuable fuel than
coal. This is why it is primarily used for fuelling blast furnaces producing pig
iron in steel and ironworks
One by-product of the baking process is the crude gas which is then siphoned
out of the ovens. The crude gas not only contains pollutants like hydrogen
sulphide but also ammonia, crude benzene and tar. These so-called by-products
are then separated from the gas in further production steps. Some of
them are cleaned up and sold on as valuable products on the market. When
coke production in Germany was at its height the by-products were important
basic materials for the chemical industry. The cleaned up coking gas – it was
known as rich gas – was sold off as fuel for steel mills and other industrial
factories, or as domestic gas in the Ruhrgebiet. Gas production was a lucrative
business for the coking industry until the mid-1960s when gas suppliers
gradually rejected it in favour of natural gas.
The production process in a coking plant is primarily divided into two main
areas. The buildings used for handling the coal and producing the coke
are known as the “black side”, and the by-products from the coking gas are
separated and cleaned up in the buildings on the “white side”. The buildings
in the Hansa coking plant make it possible for visitors not only to follow the
process of producing coke, but also to get a greater understanding of the
subsequent processing of the coking gas into its by-products.
The production process in a coking plant never stops. For this reason all the
activities including the workers’ shifts have to fulfil a single aim: to ensure
that there are no stoppages whatsoever. Once a battery of coke ovens has
been heated up – a process that often takes several months - it must in no
circumstances be allowed to cool down again, otherwise this will result in
irreparable damage to the walls of the battery. Minor interruptions in the
pressing process, or defective parts must be remedied or replaced whilst the
battery is still in operation. This demands a high level of efficiency not only
from the mechanical parts involved, but also from the workers involved in
maintaining them.
We shall now describes the path of coal and the path of the crude gas as
they pass through the various areas of production in the Hansa coking plant;
beginning with coal deliveries, continuing with the baking process and ending
with the finished coke and its by-products. The Hansa coking plant provides
an ideal example of the complex processes involved in such an industrial site.
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HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
FROM COAL TO COKE 41