TY - THES

T1 - Heat Balance of a Continuous Galvanizing Line

AU - Wagner, Helena

N1 - embargoed until null

PY - 2008

Y1 - 2008

N2 - Metal-working industries traditionally require high energy inputs for their various processes. Aware of the finiteness of natural fuel deposits, efforts are undertaken to reduce the fuel input and to increase the efficiency in order not to waste precious natural resources. In the present work the heat distribution and energy efficiency is examined for the continuous galvanizing line FVZ4 at Voestalpine Stahl GmbH in Linz. In the first part a literature survey gives an overview on the principles and developments in thermal treatment and galvanization of steel strips. Thereafter the process of the Andritz Selas furnace in Linz is described in detail, including the visualization of mass and energy flows during the operating of the line. These flow diagrams are the basis for a heat balance of the two furnace sections DFF (direct-fired furnace) and RTH/RTS (radiant tube heating/ radiant tube soaking). The quantification for each flow entering and leaving the two sub-systems is done by temperature and flow measurements. The majority of them are installed permanently to monitor and control the process; others were added for the purpose of the heat balance. The primary aim of the present work is to calculate to what extent the spent energy does account for the heating of the steel strip and what amount of energy is lost via waste gas, conduction losses through furnace walls etc. The results are presented for different kinds of steel strips varying in size, material and heat cycle. Analysis evidences a lack of correlation between entering and leaving energy flows, which leads to the conclusion that some of the applied measurements are apparently not working properly. A sensitivity analysis points out which of them have the greatest impact on the results. Finally possibilities for the optimization of the continuous galvanizing line are presented, including the consideration of a more accurate temperature and volume-monitoring and approaches to gain a higher energy efficiency of the process.

AB - Metal-working industries traditionally require high energy inputs for their various processes. Aware of the finiteness of natural fuel deposits, efforts are undertaken to reduce the fuel input and to increase the efficiency in order not to waste precious natural resources. In the present work the heat distribution and energy efficiency is examined for the continuous galvanizing line FVZ4 at Voestalpine Stahl GmbH in Linz. In the first part a literature survey gives an overview on the principles and developments in thermal treatment and galvanization of steel strips. Thereafter the process of the Andritz Selas furnace in Linz is described in detail, including the visualization of mass and energy flows during the operating of the line. These flow diagrams are the basis for a heat balance of the two furnace sections DFF (direct-fired furnace) and RTH/RTS (radiant tube heating/ radiant tube soaking). The quantification for each flow entering and leaving the two sub-systems is done by temperature and flow measurements. The majority of them are installed permanently to monitor and control the process; others were added for the purpose of the heat balance. The primary aim of the present work is to calculate to what extent the spent energy does account for the heating of the steel strip and what amount of energy is lost via waste gas, conduction losses through furnace walls etc. The results are presented for different kinds of steel strips varying in size, material and heat cycle. Analysis evidences a lack of correlation between entering and leaving energy flows, which leads to the conclusion that some of the applied measurements are apparently not working properly. A sensitivity analysis points out which of them have the greatest impact on the results. Finally possibilities for the optimization of the continuous galvanizing line are presented, including the consideration of a more accurate temperature and volume-monitoring and approaches to gain a higher energy efficiency of the process.

KW - Energiebilanz Feuerverzinkung Sensitivitätsanalyse Energieeffizienz

KW - heat balance galvanizing energy efficiency sensitivity analysis

M3 - Master's Thesis

ER -