|
Fields of
application are:
Installation in simple bath-type melting
furnaces, hearth-type melting furnaces, pouring furnaces and converters. The
requirement is that there is adequate space available on the furnace
for the two regenerators to be installed on top of it. Additionally required
is a separate waste gas pipe connection for up to 20% of the hot
waste gas in order to be able to maintain the two regenerators in
thermal balance. This waste gas pipe is
also used for operating a regenerator burner with cold air (emergency operation) to facilitate cleaning and maintenance work on one of the two
regenerator-burners. Thus, the operating availability of the furnace rises
greater as 98 %. Burner and flame shape have to be specially adapted to the furnace
geometry, with burner power up to 3600 kW per pair being simply and safely
achievable and controllable.
At furnace temperatures ranging from 900°C to 1050°C energy savings
of approximately 25% to 45% are the rule. The installation of a
regenerator-burner has an appreciable impact on smelting technology.
Specifically in the secondary aluminium industry, furnaces
(collectors, converters, pouring furnaces) equipped with regenerator burners
become cost-efficient smelting systems for lumpy, compact scrap when combined
with drum-melting furnaces. With skilful production planning, considerable salt
and dump costs can be saved if appropriate scrap is available.
In order to minimize metal losses during the melting process,
controlled volume
flow of fuel/air ratio is absolutely necessary.
This is
illustrated clearly by a simple calculation.
At an annual production output of
50,000 t/year and an increased melting loss of 1 %, the financial loss is
770.000 EUR at 1.54 EUR/kg. Better amortization
rates for the installation of an efficient fuel/air ratio control system and
regular maintenance are achievable almost nowhere. In larger installations, an (expensive but more
precise) electronic fuel/air ratio control is indispensable.
Specifically in converters of the
secondary aluminium industry where cleaning of the molten aluminium bath is
carried out by blowing a gas mixture (or salt) into it, it is meaningful to
use regenerators for heat recycling. The process of bath cleaning is supported
and optimized by a special programmed chip in the burner control software.
After initial difficulties involved in
cleaning the regenerators (learning process) the system now proves practicable
and economic. Systems of this type have been in operation for over ten years.
At this writing, additional exchange regenerators can be used which can be
exchanged, under production conditions, for cleaning within a brief period of
time. To achieve this, sensible maintenance management is most helpful. |
