Syngas production with low tar content from cellulose pyrolysis in molten salt combined with Ni/Al<inf>2</inf>O<inf>3</inf> catalyst

Abstract

The syngas production from cellulose pyrolysis was studied in carbonate salts combined with nickel supported on alumina catalyst (MS-Ni) in a preheated reactor. Tar content was greatly reduced by 10 folds when compared to that of the pyrolysis in argon gas (Ar). Molten salt resulted in the reduction of tar and CO2 formation due to the rapid heating of 141 °C/s alter the pyrolysis pathway to produce more syngas products. Further tar elimination was promoted with the presence of nickel supported on alumina catalyst in the salt. Tar was reduced by 5 folds when compared to that the pyrolysis in sole molten salt (MS). Tar from pyrolysis in MS-Ni was about 1 wt%. In addition, CH4 could be reformed with CO2 into additional syngas over the Ni/Al2O3 catalyst. As a result, the pyrolysis in the combined salt and catalyst exhibited high syngas yield at 824 mL/g cellulose. Moreover, alumina particles enhanced the heat transfer in the molten salt, resulting in the highest heating rate of 181 °C/s obtained in MS-Ni medium. However, the catalyst deactivation was a serious issue in combining molten salt with Ni/Al2O3 catalyst. The high corrosiveness would damage the alumina support, while the Ni active metal would be leached from the catalyst particles, resulting in the catalyst deactivation.