THERMAL SCIENCE

International Scientific Journal

THE EFFECT OF STEAM ON AIR GASIFICATION OF MECHANICALLY ACTIVATED COAL IN A FLOW REACTOR

ABSTRACT
A combined steam-gas plant with in-cycle steam gasification of coal and hot gas purification is considered as a promising technology for increasing the efficiency of energy production with simultaneous reduction in environmental impact. To intensify steam-air gasification, mechanical activation of fuel is used; it consists in high-stress grinding in a mill-disintegrator. The supply of steam to the gasifier allows an increase in reactivity of fuel, suppression of sorbent decomposition in the unit of hot desulfurization, reduction in the steam load on the shift reactor, increase in useful external work of gas turbine expansion, reduction in nitrogen oxide formation, and general increase in the efficiency and ecological compatibility of energy generation. On the other hand, a significant amount of steam can deteriorate the heat balance and efficiency of the gasifier. In this work, the influence of the steam/fuel ratio on steam-air gasification of mechanically activated Kuznetsk coal in a flow reactor was studied experimentally. The excess air coefficient was maintained constant and equal to 0.51, which corresponded to a temperature at the reactor outlet of about 1100°C. When steam was supplied, the fuel and air-flow rates were adjusted to ensure a constant gas-dynamic regime. To evaluate the obtained regimes, the heat and material balances were compiled. A positive effect of steam on characteristics of the gasification process was revealed. For the studied coal, the maximum degree of coal conversion and the calorific value of synthesis gas are achieved with a steam/fuel ratio of about 0.4 kg/kg.
KEYWORDS
PAPER SUBMITTED: 2020-06-01
PAPER REVISED: 2020-06-14
PAPER ACCEPTED: 2020-06-27
PUBLISHED ONLINE: 2020-07-11
DOI REFERENCE: https://doi.org/10.2298/TSCI200601208N
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2021, VOLUME 25, ISSUE Issue 1, PAGES [321 - 330]
REFERENCES
  1. Giuffrida, A. et al., Thermodynamic assessment of IGCC power plants with hot fuel gas desulfurization, Applied Energy, 87 (2010), pp. 3374-3383
  2. Zheng, L. et al., Comparison of Shell, Texaco, BGL and KRW gasifiers as part of IGCC plant computer simulations, Energy Conversion and Management, 46 (2005), pp. 1767-1779
  3. Cau, G. et al., Comparative performance assessment of USC and IGCC power plants integrated with CO2 capture systems, Fuel, 116 (2014), pp. 820 - 833
  4. Damen, K. et al., Performance and modelling of the pre-combustion capture pilot plant at the Buggenum IGCC, Energy Procedia 63 (2014), pp. 6207 - 6214
  5. Giuffrida, A. et al., Efficiency enhancement in IGCC power plants with air-blown gasification and hot gas clean-up, Energy 53 (2013), pp. 221-229
  6. Ryzhkov, A. et al., Technological solutions for an advanced IGCC plant, Fuel 214 (2018), pp. 63-72
  7. Burdukov, A. et al., Mechanical activation of micronized coal: Prospects for new combustion applications, Applied Thermal Engineering 74 (2014), pp. 174-181
  8. Liu, J. et al., Influences of particle size, ultraviolet irradiation and pyrolysis temperature on stable free radicals in coal, Powder Technology 272 (2015), pp. 64-74
  9. Burdukov, A. et al., Autothermal combustion of mechanically-activated micronized coal in a 5 MW pilot-scale combustor, Fuel 122 (2014), pp. 103-111.
  10. Abaimov, N. et al., Investigation of two-stage air-blown and air-steam-blown entrained-flow coal gasification, J. Phys. Conf. Ser. 899 (2017), 092001.
  11. Prationo, W. et al., Influence of steam on ignition of Victorian brown coal particle stream in oxy-fuel combustion: In-situ diagnosis and transient ignition modelling, Fuel 181 (2016), pp. 1203-1213
  12. Ju, Y. et al., Evaluation of the energy efficiency of the shell coal gasification process by coal type, Energy Conversion and Management 143 (2017), pp. 123-136
  13. Briesemeister, L. et al. Air-Blown Entrained-Flow Gasification of Biocoal from Hydrothermal Carbonization, Chem. Eng. Technol. 40 (2017), pp. 270-277
  14. Abaimov, N. et al., Investigation of hydrodynamic features in two-stage steam-air-blown entrained-flow gasifier, J. Phys. Conf. Ser. 1261 (2019), 012001.

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence