The Effects of Ca(OH)₂ on the Steam Gasification Process of Acid-Washed and Raw Lignite

Abstract:

The effect of Ca (OH)₂ prepared by the wet-mixing method on acid-washed and raw lignite steam gasification process at 800°C were analyzed in a spout-fluid bed reactor. The addition of Ca (OH)₂ on acid-washed lignite obviously increased the coal conversion, gas yield and reduced the tar yield, and the Ca (OH)₂ addition on raw lignite significantly reduced the tar yield but just slightly increased the coal conversion and gas yield. As a catalyst, Ca (OH)₂ can promote the tar steam reforming in the gasification process. Based on GC-MS data, it can be deduced that Ca (OH)₂ has different catalytic activity on the steam reforming of tar with different molecular structures. Aliphatic hydrocarbons, Class 2 and Class 5 tars were clearly catalytic reformed, while the concentration of Class 4 tars increased. The CO concentration decreased and the CO₂ and H₂ concentration increased with the addition of Ca (OH)₂ on both acid-washed and raw lignites, which was mainly caused by the catalytic effect of Ca (OH)₂ on WGS reaction. The effect of Ca (OH)₂ addition on acid-washed lignite was more significant than on raw lignite, and no adsorption of CO₂ was detected in the process by using active carbon as a model compound_.

• Periodical: Advanced Materials Research (Volume 1102)
• Pages: 161-168
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1102.161
• Online since: May 2015
• Authors: Chao Shuai, Song Hu*, Jun Xiang, Sheng Su, Lu Shi Sun, Yi Wang
• Keywords: Ca(OH)₂, Lignite, Steam Gasification, Tar Reforming, WGS Reaction

References

[1] S. Kajitani, H. -L. Tay, S. Zhang, C. -Z. Li, Mechanisms and kinetic modelling of steam gasification of brown coal in the presence of volatile–char interactions, Fuel. 103 (2013) 7-13.

DOI: 10.1016/j.fuel.2011.09.059

[2] Y. K. Kim, J. I. Park, D. Jung, J. Miyawaki, S. H. Yoon, I. Mochida, Low-temperature catalytic conversion of lignite: 1. Steam gasification using potassium carbonate supported on perovskite oxide, Journal of Industrial and Engineering Chemistry. 20 (2014).

DOI: 10.1016/j.jiec.2013.04.004

[3] Y. Ohtsuka, K. Asami, Steam gasification of coals with calcium hydroxide, Energy & Fuels. 9 (1995) 1038-1042.

DOI: 10.1021/ef00054a016

[4] Y. Ohtsuka, K. Asami, Ion-Exchanged Calcium from Calcium Carbonate and Low-Rank Coals:  High Catalytic Activity in Steam Gasification, Energy & Fuels. 10 (1996) 431-435.

DOI: 10.1021/ef950174f

[5] N. Kayembe, A. H. Pulsifer, Kinetics and catalysis of the reaction of coal char and steam, Fuel. 55 (1976) 211-216.

DOI: 10.1016/0016-2361(76)90090-9

[6] C. C. Dean, J. Blamey, N. H. Florin, M. J. Al-Jeboori, P. S. Fennell, The calcium looping cycle for CO2 capture from power generation, cement manufacture and hydrogen production, Chemical Engineering Research and Design. 89 (2011) 836-855.

DOI: 10.1016/j.cherd.2010.10.013

[7] A. K. Dalai, E. Sasaoka, H. Hikita, D. Ferdous, Catalytic Gasification of Sawdust Derived from Various Biomass, Energy & Fuels. 17 (2003) 1456-1463.

DOI: 10.1021/ef030037f

[8] L. Wei, S. Xu, L. Zhang, C. Liu, H. Zhu, S. Liu, Steam gasification of biomass for hydrogen-rich gas in a free-fall reactor, International Journal of Hydrogen Energy. 32 (2007) 24-31.

DOI: 10.1016/j.ijhydene.2006.06.002

[9] G. Xu, T. Murakami, T. Suda, S. Kusama, T. Fujimori, Distinctive Effects of CaO Additive on Atmospheric Gasification of Biomass at Different Temperatures, Industrial & Engineering Chemistry Research. 44 (2005) 5864-5868.

DOI: 10.1021/ie050432o

[10] Y. Jia, J. Huang, Y. Wang, Effects of Calcium Oxide on the Cracking of Coal Tar in the Freeboard of a Fluidized Bed, Energy & Fuels. 18 (2004) 1625-1632.

DOI: 10.1021/ef034077v

[11] D. Sutton, B. Kelleher, J. R. H. Ross, Review of literature on catalysts for biomass gasification, Fuel Processing Technology. 73 (2001) 155-173.

DOI: 10.1016/s0378-3820(01)00208-9

[12] L. Devi, K. J. Ptasinski, F. J. J. G. Janssen, A review of the primary measures for tar elimination in biomass gasification processes, Biomass and Bioenergy. 24 (2003) 125-140.

DOI: 10.1016/s0961-9534(02)00102-2

[13] J. Udomsirichakorn, P. Basu, P. A. Salam, B. Acharya, Effect of CaO on tar reforming to hydrogen-enriched gas with in-process CO2 capture in a bubbling fluidized bed biomass steam gasifier, International Journal of Hydrogen Energy. 38 (2013).

DOI: 10.1016/j.ijhydene.2013.09.055

[14] C. A. Jordan, G. Akay, Effect of CaO on tar production and dew point depression during gasification of fuel cane bagasse in a novel downdraft gasifier, Fuel Processing Technology. 106 (2013) 654-660.

DOI: 10.1016/j.fuproc.2012.09.061

[15] G. Skodras, G. P. Sakellaropoulos, Mineral matter effects in lignite gasification, Fuel Processing Technology. 77–78 (2002) 151-158.

DOI: 10.1016/s0378-3820(02)00063-2

[16] Z. Min, M. Asadullah, P. Yimsiri, S. Zhang, H. Wu, C. -Z. Li, Catalytic reforming of tar during gasification. Part I. Steam reforming of biomass tar using ilmenite as a catalyst, Fuel. 90 (2011) 1847-1854.

DOI: 10.1016/j.fuel.2010.12.039

[17] D. M. Quyn, H. Wu, J. -i. Hayashi, C. -Z. Li, Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part IV. Catalytic effects of NaCl and ion-exchangeable Na in coal on char reactivity☆, Fuel. 82 (2003).

DOI: 10.1016/s0016-2361(02)00323-x

[18] T. Zhu, S. Zhang, J. Huang, Y. Wang, Effect of calcium oxide on pyrolysis of coal in a fluidized bed, Fuel Processing Technology. 64 (2000) 271-284.

DOI: 10.1016/s0378-3820(00)00075-8

[19] L. Devi, K. J. Ptasinski, F. J. J. G. Janssen, S. V. B. van Paasen, P. C. A. Bergman, J. H. A. Kiel, Catalytic decomposition of biomass tars: use of dolomite and untreated olivine, Renewable Energy. 30 (2005) 565-587.

DOI: 10.1016/j.renene.2004.07.014

[20] R. Coll, J. Salvadó, X. Farriol, D. Montané, Steam reforming model compounds of biomass gasification tars: conversion at different operating conditions and tendency towards coke formation, Fuel Processing Technology. 74 (2001) 19-31.

DOI: 10.1016/s0378-3820(01)00214-4

[21] N. H. Florin, A. T. Harris, Enhanced hydrogen production from biomass with in situ carbon dioxide capture using calcium oxide sorbents, Chemical Engineering Science. 63 (2008) 287-316.

DOI: 10.1016/j.ces.2007.09.011