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

Yosuke Komatsu, Anna Sciazko, Marcin Zakrzewski, Taro Akiyama, Akira Hashimoto, Naoki Shikazono, Shozo Kaneko, Shinji Kimijima, Janusz S. Szmyd, Yoshinori Kobayashi

Research output: Contribution to journalArticle

3 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)1757-1772
Number of pages16
JournalInternational Journal of Energy Research
Volume40
Issue number13
DOIs
Publication statusPublished - 2016 Oct 25

Keywords

  • ash fusibility
  • gasification
  • lignite
  • lignite drying
  • lignite upgrading
  • molten slag
  • polish deposits
  • superheated steam drying

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

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