Toluene Steam Reforming over Ni/CeZrO2—The Influence of Steam to Carbon Ratio and Contact Time on the Catalyst Performance and Carbon Deposition

Agata Łamacz

doi:10.3390/catal12020219

Abstract

The formation of tars during coal or biomass gasification is a serious issue resulting in decreasing efficiency of the process and increased maintenance costs. The decomposition of tars can be conducted via catalytic steam reforming that enriches the produced gas in hydrogen. Nevertheless, the catalyst should be characterized by high activity, stability, and resistance towards carbon deposition. Ceria-zirconia supported nickel (Ni/CeZrO2) is a very good candidate to catalyze tar removal—Ni is an active phase for reforming reactions, while CeZrO2 provides the active sites that play important roles in protecting the catalyst from carbon deposition. Ni/CeZrO2 shows high activity in the steam reforming of model tar compounds. In this paper, its performance in the steam reforming of toluene and carbon deposition is discussed considering the changing parameters of the reaction: the temperature, steam to carbon ratio, and the contact time.

Highlights

Influence of Steam to Carbon RatioBoth coal and biomass gasification are accompanied by the formation of tars that negatively influence the efficiency and total cost of the process
Catalytic Runs of Toluene Steam Reforming over CeZrO2 and Ni/CeZrO2
Ni/CeZrO2 conducted at steam to carbon ratio (S/C) = 2.4 and tc = 0.36 s are presented in Table 1, which shows that toluene converts mainly to CO and CO2, with some insignificant transformation to benzene in the reaction of steam dealkylation (Equation (5))

Summary

Introduction

Both coal and biomass gasification are accompanied by the formation of tars that negatively influence the efficiency and total cost of the process. The most widely used techniques for tar removal are thermal cracking, steam reforming, and mechanical separation [1]. The latter, efficient, has a significant negative impact on the environment. The main reactions occurring during steam reforming process are steam reforming (SR) (Equation (1)), total oxidation (Equation (2)), water gas shift (WGS).

Methods

Results

Conclusion