Image-based Method for Measuring Pellet Size Distribution in the Stable Area of Disc Pelletizer

Abstract

Disc pelletizer is widely used in the agglomeration process to form powdered iron ore into iron ore green pellets. The pellet size distribution (PSD) is one of the major measures of product quality. An imaging system is developed for measuring PSD in the stable area of the disc pelletizer. Image pre-processing is performed to extract the densely distributed pellets as foreground, followed by identifying surface pellets using pellet markers and K-means clustering method. Then a marker-controlled watershed algorithm is applied to segment overlapping pellets in the image. The pellet sizes and thus PSD are then obtained using circumscribed circle fitting. The proposed image-based measuring method was tested in a steel company. The measured PSD was compared with manual sieving results. It shows good accuracy for different size ranges under different pelletizing conditions. The proposed method also makes it possible to evaluate online the pellet quality.

Evaluation of Deep Network-based Methods for Crack Detection of Iron Ore Green Pellet

“…With the rapid development of image processing technology, image-based method can be adopted to achieve the automatic detection of pellet cracks. 4) However, here comes some difficulties when adopting the image processing algorithm for pellet crack detection: (1) Cracks with different types appear in pellet surface after dropping, including long crack, short crack, wide crack, short crack, etc. (2) Several material stains and water stains are inevitably remained on the steel plate after pellet dropping, leading to the complex background in captured images.…”

Experimental Analysis of Image Dehazing Algorithms for Pelletization Process Images

“…Xin WU, 1,2) Xiaoyan LIU 1,3) * and Fei YUAN 1) 1) College of Electrical November 11, 2020) The product quality of pelletization process in steel industry is usually monitored by machine vision system. However, the image quality deteriorates significantly by haze generated during pelletization.…”

“…In order to improve the measuring accuracy of pellet size, many useful algorithms were proposed to cope with uneven illumination and light reflection problems in processing of pellet images. 1,4) However, up to now, little effort has been made to the problem of haze removal from green pellet images in the metallurgical process, as presented in Fig. 1(c) for example.…”

“…Pelletization is a size-enlargement process to mold powder particles into the shape of pellets, which is a common process used in metallurgical and chemical industries. 1) Figure 1 gives an example of pelletization process in rotary disc equipment in steel industry. The hybrid raw material of iron ore fines, bentonite, and other powders are conveyed into a rotary disc and sprayed from above.…”

“…Pellet size distribution is an important quality control index, because it greatly affects the energy consumption and producing efficiency in the following sintering process in blast furnace. [1][2][3] In recent years, machine vision has become a popular method for online monitoring the size distribution of green…”