Effects of inherent potassium on the catalytic performance of Ni/biochar for steam reforming of toluene as a tar model compound

doi:10.1016/j.cjche.2020.06.010

Abstract

Abstract: Biochar supported nickel (Ni/BC) has been widely studied as a cheap and easy-to-prepare catalyst with potential applications in tar reforming during the gasification of low-rank fuels, such as brown coal and biomass. However, the role and behaviors of inherent K species, especially their interactions with Ni particles and the biochar support, are not well understood yet. In this work, three Ni/BC catalysts with varying K amount were prepared from raw, water-washed, and acid-washed biomass. They were used in steam reforming of toluene as a tar model compound to elucidate the effects of inherent K on the catalytic activity and stability. Detailed characterization indicated that K enhanced water adsorption due to its hydroscopicity and lowered the condensation and graphitization degrees of biochar, but the alteration to the electronic state of Ni was not observed. These effects together led to a temperature-dependent role of K. That is, at relatively low temperatures of 450 and 500℃, toluene conversion was increased in the presence of K, due to the increased concentration of adsorbed water around Ni particles. By contrast, at relatively higher temperatures of 550 and 600℃, although initial high activity was achieved, Ni/BC with K deactivated rapidly because of the accelerated consumption of the biochar support.

Key words: Catalyst, Instability, Steam reforming of toluene, Adsorption, Ni/biochar, Potassium

摘要： Biochar supported nickel (Ni/BC) has been widely studied as a cheap and easy-to-prepare catalyst with potential applications in tar reforming during the gasification of low-rank fuels, such as brown coal and biomass. However, the role and behaviors of inherent K species, especially their interactions with Ni particles and the biochar support, are not well understood yet. In this work, three Ni/BC catalysts with varying K amount were prepared from raw, water-washed, and acid-washed biomass. They were used in steam reforming of toluene as a tar model compound to elucidate the effects of inherent K on the catalytic activity and stability. Detailed characterization indicated that K enhanced water adsorption due to its hydroscopicity and lowered the condensation and graphitization degrees of biochar, but the alteration to the electronic state of Ni was not observed. These effects together led to a temperature-dependent role of K. That is, at relatively low temperatures of 450 and 500℃, toluene conversion was increased in the presence of K, due to the increased concentration of adsorbed water around Ni particles. By contrast, at relatively higher temperatures of 550 and 600℃, although initial high activity was achieved, Ni/BC with K deactivated rapidly because of the accelerated consumption of the biochar support.

关键词: Catalyst, Instability, Steam reforming of toluene, Adsorption, Ni/biochar, Potassium

Chen Xu, Zhenyi Du, Shiqi Yang, Hongda Ma, Jie Feng. Effects of inherent potassium on the catalytic performance of Ni/biochar for steam reforming of toluene as a tar model compound[J]. Chinese Journal of Chemical Engineering, 2021, 35(7): 189-195.

References

[1] Y. Richardson, J. Blin, G. Volle, J. Motuzas, A. Julbe, In situ generation of Ni metal nanoparticles as catalyst for H₂-rich syngas production from biomass gasification, Appl. Catal. A Gen. 382(2) (2010) 220-230.
[2] S. Zhang, Y.G. Luo, C.Z. Li, Y.G. Wang, Changes in char reactivity due to char-oxygen and char-steam reactions using victorian brown coal in a fixed-bed reactor, Chin. J. Chem. Eng. 23(2015) 321-325.
[3] L. Ding, Z. Zhou, W. Huo, G. Yu, Comparison of steam-gasification characteristics of coal char and petroleum coke char in drop tube furnace, Chin. J. Chem. Eng. 23(7) (2015) 1214-1224.
[4] Z.H. Min, P. Yimsiri, M. Asadullah, S. Zhang, C.Z. Li, Catalytic reforming of tar during gasification. Part II. Char as a catalyst or as a catalyst support for tar reforming, Fuel 90(7) (2011) 2545-2552.
[5] K. Qian, A. Kumar, Catalytic reforming of toluene and naphthalene (model tar) by char supported nickel catalyst, Fuel. 187(2017) 128-136.
[6] J. Tao, Q. Lu, C. Dong, X. Du, E. Dahlquist, Effects of electric current upon catalytic steam reforming of biomass gasification tar model compounds to syngas, Energy Convers. Manag. 100(2015) 56-63.
[7] S. Zhang, Z. Chen, H. Zhang, Y. Wang, X. Xu, L. Cheng, Y. Zhang, The catalytic reforming of tar from pyrolysis and gasification of brown coal:Effects of parental carbon materials on the performance of char catalysts, Fuel Process. Technol. 174(2018) 142-148.
[8] Y. Qin, A. Campen, T. Wiltowski, J. Feng, W. Li, The influence of different chemical compositions in biomass on gasification tar formation, Biomass Bioenergy 83(2015) 77-84.
[9] G.Q. Guan, M. Kaewpanha, X.G. Hao, A. Abudula, Catalytic steam reforming of biomass tar:Prospects and challenges, Renew. Sust. Energ. Rev. 58(2016) 450-461.
[10] D.D. Yao, Q. Hu, D.Q. Wang, H.P. Yang, C.F. Wu, X.H. Wang, H.P. Chen, Hydrogen production from biomass gasification using biochar as a catalyst/support, Bioresour. Technol. 216(2016) 159-164.
[11] J. Lee, K.H. Kim, E.E. Kwon, Biochar as a catalyst, Renew. Sust. Energ. Rev. 77(2017) 70-79.
[12] X. Xiao, J. Cao, X. Meng, D.D. Le, L. Li, Y. Ogawa, K. Sato, T. Takarada, Synthesis gas production from catalytic gasification of waste biomass using nickelloaded brown coal char, Fuel. 103(2013) 135-140.
[13] Y.F. Shen, Chars as carbonaceous adsorbents/catalysts for tar elimination during biomass pyrolysis or gasification, Renew. Sust. Energ. Rev. 43(2015) 281-295.
[14] L. Li, K. Morishita, H. Mogi, K. Yamasaki, T. Takarada, Low-temperature gasification of a woody biomass under a nickel-loaded brown coal char, Fuel Process. Technol. 91(8) (2010) 889-894.
[15] D. Wang, W.Q. Yuan, W. Ji, Char and char-supported nickel catalysts for secondary syngas cleanup and conditioning, Appl. Energy 88(5) (2011) 1656-1663.
[16] J.P. Cao, T.L. Liu, J. Ren, X.Y. Zhao, Y. Wu, J.X. Wang, X.Y. Ren, X.Y. Wei, Preparation and characterization of nickel loaded on resin char as tar reforming catalyst for biomass gasification, J. Anal. Appl. Pyrol. 127(2017) 82-90.
[17] Z. Min, P. Yimsiri, M. Asadullah, S. Zhang, C.Z. Li, Catalytic reforming of tar during gasification. Part II. Char as a catalyst or as a catalyst support for tar reforming, Fuel 90(7) (2011) 2545-2552.
[18] C. Shen, W. Zhou, H. Yu, L. Du, Ni nanoparticles supported on carbon as efficient catalysts for steam reforming of toluene (model tar), Chin. J. Chem. Eng. 26(2) (2018) 322-329.
[19] Z.Y. Du, Z.H. Zhang, C. Xu, X.B. Wang, W.Y. Li, Low-temperature steam reforming of toluene and biomass tar over biochar-supported Ni nanoparticles, ACS Sustain. Chem. Eng. 7(3) (2019) 3111-3119.
[20] S. Hu, L. Jiang, Y. Wang, S. Su, L.S. Sun, B.Y. Xu, L.M. He, J. Xiang, Effects of inherent alkali and alkaline earth metallic species on biomass pyrolysis at different temperatures, Bioresour. Technol. 192(2015) 23-30.
[21] Y.B. Li, X.Y. Chen, C.Y. Wang, C.B. Zhang, H. He, Sodium enhances Ir/TiO₂ activity for catalytic oxidation of formaldehyde at ambient temperature, ACS Catal. 8(12) (2018) 11377-11385.
[22] Y.X. Wang, G.C. Wang, Water dissociation on clean and potassium preadsorbed transition metals:A systematic theoretical study, J. Phys. Chem. C 122(27) (2018) 15474-15484.
[23] K.Y. Yip, F.J. Tian, J.i. Hayashi, H.W. Wu, Effect of alkali and alkaline earth metallic species on biochar reactivity and syngas compositions during steam gasification, Energy Fuel 24(1) (2009) 173-181.
[24] D. Feng, Y. Zhao, Y. Zhang, S. Sun, J. Gao, Steam gasification of sawdust biochar influenced by chemical speciation of alkali and alkaline earth metallic species, Energies. 11(1) (2018) 205.
[25] D. S ′wierczyń ski, S. Libs, C. Courson, A. Kiennemann, Steam reforming of tar from a biomass gasification process over Ni/olivine catalyst using toluene as a model compound, Appl. Catal. B Environ. 74(3) (2007) 211-222.
[26] A. Sattar, G.A. Leeke, A. Hornung, J. Wood, Steam gasification of rapeseed, wood, sewage sludge and miscanthus biochars for the production of a hydrogen-rich syngas, Biomass Bioenergy 69(2014) 276-286.
[27] Y. Richardson, J. Motuzas, A. Julbe, G. Volle, J. Blin, Catalytic investigation of in situ generated Ni metal nanoparticles for tar conversion during biomass pyrolysis, J. Phys. Chem. C 117(45) (2013) 23812-23831.
[28] D.M. Keown, X.J. Li, J.i. Hayashi, C.Z. Li, Characterization of the structural features of char from the pyrolysis of cane trash using Fourier transformRaman spectroscopy, Energy Fuel 21(2007) 1816-1821.
[29] H.W. Wu, K. Yip, F.J. Tian, Z.L. Xie, C.Z. Li, Evolution of char structure during the steam gasification of biochars produced from the pyrolysis of various Mallee biomass components, Ind. Eng. Chem. Res. 48(23) (2009) 10431-10438.
[30] X.J. Li, J.i. Hayashi, C.Z. Li, FT-Raman spectroscopic study of the evolution of char structure during the pyrolysis of a Victorian brown coal, Fuel 85(12-13) (2006) 1700-1707.
[31] X.J. Li, 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 VII. Raman spectroscopic study on the changes in char structure during the catalytic gasification in air, Fuel 85(10-11) (2006) 1509-1517.
[32] L.F. Xu, H. Liu, H. Fang, J.H. Gao, S.H. Wu, Effects of various inorganic sodium salts present in Zhundong coal on the char characteristics, Fuel. 203(2017) 120-127.
[33] S.Q. Xu, Z.J. Zhou, J. Xiong, G.S. Yu, F.C. Wang, Effects of alkaline metal on coal gasification at pyrolysis and gasification phases, Fuel. 90(5) (2011) 1723-1730.
[34] K. Yip, H.W. Wu, D.K. Zhang, Effect of inherent moisture in collie coal during pyrolysis due to in-situ steam gasification, Energy Fuel 21(5) (2007) 2883-2891.
[35] F. Frusteri, F. Arena, G. Calogero, T. Torre, A. Parmaliana, Potassium-enhancd stability of Ni/MgO catalysts in the dry-reforming of methane, Catal. Commun. 2(2) (2001) 49-56.
[36] H. Praliaud, M. Primet, G.A. Martin, Physico-chemical properties of potassiumpromoted Ni/SiO₂ catalysts, Appl. Surf. Sci. 17(1) (1983) 107-123.
[37] A. Iordan, M.I. Zaki, C. Kappenstein, C. Géron, XPS and in situ IR spectroscopic studies of CO/Rh/Al₂O₃ and CO/Rh/K-Al₂O₃ at high temperatures:probing the impact of the potassium functionalization of the support, Phys. Chem. Chem. Phys. 5(8) (2003) 1708-1715.
[38] https://srdata.nist.gov/xps/.
[39] D.D. Feng, Y.J. Zhao, Y. Zhang, Z.B. Zhang, L.Y. Zhang, S.Z. Sun, In-situ steam reforming of biomass tar over sawdust biochar in mild catalytic temperature, Biomass Bioenergy 107(2017) 261-270.
[40] S. Mani, J.R. Kastner, A. Juneja, Catalytic decomposition of toluene using a biomass derived catalyst, Fuel Process. Technol. 114(2013) 118-125.
[41] Q.T. Trinh, A.V. Nguyen, D.C. Huynh, T.H. Pham, S.H. Mushrif, Mechanistic insights into the catalytic elimination of tar and the promotional effect of boron on it:first principles study using toluene as a model compound, Catal. Sci. Technol. 6(15) (2016) 5871-5883.
[42] Y. Ma, B.Liu, M. Jing, R.Zhang, J. Chen,Y. Zhang, J. Li, Promoted potassium salts based Ru/AC catalysts for water gas shift reaction, Chem. Eng. J. 287(2016) 155-161.
[43] B. Liu, T. Huang, Z. Zhang, Z. Wang, Y. Zhang, J. Li, The effect of the alkali additive on the highly active Ru/C catalyst for water gas shift reaction, Catal. Sci. Technol. 4(5) (2014) 1286-1292.
[44] M. Kusche, F. Enzenberger, S. Bajus, H. Niedermeyer, A. Bosmann, A. Kaftan, M. Laurin, J. Libuda, P. Wasserscheid, Enhanced activity and selectivity in catalytic methanol steam reforming by basic alkali metal salt coatings, Angew. Chem. Int. Ed. 52(19) (2013) 5028-5032.
[45] Y. Matsumura, T. Nakamori, Steam reforming of methane over nickel catalysts at low reaction temperature, Appl. Catal. A Gen. 258(1) (2004) 107-114.
[46] J.W.C. Liberatori, R.U. Ribeiro, D. Zanchet, F.B. Noronha, J.M.C. Bueno, Steam reforming of ethanol on supported nickel catalysts, Appl. Catal. A Gen. 327(2) (2007) 197-204.
[47] K. Yip, M. Xu, C.Z. Li, S.P. Jiang, H. Wu, Biochar as a fuel:3. Mechanistic understanding on biochar thermal annealing at mild temperatures and its effect on biochar reactivity, Energy Fuel 25(1) (2011) 406-414.