High Temperature Corrosive Environment in a Sintering Plant for Pig Iron Production and Its Effect on Different Steel Grades
The harsh environment in a sintering plant for pig iron production leads to high temperature corrosion of the sinter grates. In the present study, a detailed analysis of the corrosives in such applications is given to understand materials failure. Various steels are tested, revealing effects of various alloying concepts, the resulting phases and their corrosive behavior in this complex corrosive environment at ≈900 °C. In order to understand the underlying corrosion mechanisms, detailed analyses are performed. Results indicate mainly chlorine, sulfur, and oxidation based corrosive decay at elevated temperature and a high relevance of protecting alloying elements within the steels.
High temperature corrosion studies of cermet particle reinforced NiCrBSi hardfacings
Abstract Metal matrix composite hardfacings provide various types of heat and wear resistant products. They are widely used in high temperature aggressive environments due to their excellent high temperature corrosion and wear resistance. In this study, Cr3C2–Ni and TiC–NiMo particles were used to reinforce a NiCrBSi matrix in plasma transferred arc welding process. These cermet particle reinforced hardfacings were examined on their oxidation behaviour and high temperature corrosion in different solid salts to optimise the field of application under high temperature conditions. Corrosion behaviour in solid salts is strongly dependent on the corroding anion. Cr3C2–Ni reinforced hardfacings behave better in oxidative and sulphate/phosphate environment, while TiC–NiMo hardfacings show better resistance against chlorine and carbonate ions up to 700 °C. Additionally, oxidation is no critical exposure for these types of hardfacings.
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.