Towards the improvement of thermal efficiency in lignite‐fired power generation: Concerning the utilization of Polish lignite deposits in state‐of‐the‐art IGCC technology |
| |
| Authors: | Yosuke Komatsu Anna Sciazko Marcin Zakrzewski Taro Akiyama Akira Hashimoto Naoki Shikazono Shozo Kaneko Shinji Kimijima Janusz S Szmyd Yoshinori Kobayashi |
| |
| Affiliation: | 1. Shibaura Institute of Technology, Graduate School of Engineering and Science, Division of Regional Environment Systems, Saitama‐shi, Saitama, Japan;2. The University of Tokyo, Institute of Industrial Science, Meguro‐ku, Tokyo, Japan;3. AGH University of Science and Technology, Faculty of Energy and Fuels, Department of Fundamental Research in Energy Engineering, Krakow, Poland;4. Shibaura Institute of Technology, College of Systems Engineering and Science, Department of Machinery and Control Systems, Saitama‐shi, Saitama, Japan |
| |
| Abstract: | Integrated coal Gasification Combined Cycle (IGCC) is the most advanced technology for coal‐fired power generation. The two‐stage entrained flow gasification process allows for the use of a wide range of coal, as long as the gasification temperature is above the ash melting point of a used fuel. In this gasification technology, lignite, which often has a low ash melting point, can be preferably utilized. However, ash fluidity is also another importance, because the behaviour of molten slag can diminish a stable ash discharge from a gasifier. As the eligibility of coal ash properties is a considerable factor, water physically and chemically kept in lignite (30 – 60% in mass) attributes to deteriorating gasification efficiency, because it causes significant heat loss and increasing oxygen consumption. Developing a thermal evaporative lignite drying method will be a necessary attempt to apply lignite to the coal gasification process. For those preceded objectives, coal and ash properties and drying characteristics of several grades of Polish lignite, extracted from Belchatow and Turow deposits, have been experimentally investigated in a preliminary study evaluating the applicability and consideration for its utilization in state‐of‐the‐art clean coal technology, IGCC. This paper particularly discusses the eligibility of Polish lignite from the perspective of the fusibility and fluidity of ash melts and the fundamental drying kinetics of lignite in superheated steam in the light of water removal. The viscosity of ash melts is measured at high temperature up to 1700 °C. In the drying tests, the significant influence of structural issues, because of the provenance and origin of lignite on the drying characteristics, was found by applying the method of sensitivity analysis of physical propensity. This paper concludes that the investigated Polish lignite has characteristics favourable for utilization in IGCC technology, once the precautions related to its high moisture have been carefully addressed. Copyright © 2016 John Wiley & Sons, Ltd. |
| |
| Keywords: | lignite polish deposits gasification ash fusibility molten slag lignite upgrading lignite drying superheated steam drying |
|
|
