Continuous Catalytic Tar Reforming of Biomass Derived Raw Gas with Simultaneous Catalyst Regeneration

Abstract

A novel concept for secondary catalytic tar cleaning with simultaneous regeneration of the catalysts is presented in this work. The process is demonstrated by an initial experiment with producer gas from the Chalmers biomass gasifier using ilmenite (FeTiO3) as catalytic bed material. The tar cleaning system was operated at 800 °C and fed with raw gas from the Chalmers biomass gasifier, in which silica sand was used as bed material and the gasification was performed with steam. The tar content of the gas emerging from the gasifier was roughly 30 gtar/Nm3 gas. The experiment showed that the catalyst was continuously regenerated from carbon deposits, and the ilmenite reduced the total amount of tar by 35% at a gas residence time in the bed of 0.4–0.5 s. Branched hydrocarbons and phenols were more or less completely reformed, while there was an increase of stable aromatic rings (benzene, naphthalene). The catalyst showed high activity in water-gas shift reactions, and the H2/CO ratio was shifted from around 0.7 prior to the reactor to almost 3 after the reactor.

Characterization and evaluation of Ni/SiO2 catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

“…In the present work, a quantitative analysis is presented, giving detailedinformation on the distribution of compounds in the tars. Some of the compounds identified here have been previously reported by others for the pyrolysis of RDF [52] and for biomass reforming using a secondary tar cleaning system [14].…”

“…A set of decomposition reactions, have been proposed by Simell et al [13], using toluene as a tar model compound; and include steam reforming, steam dealkylation, hydrocracking, hydrodealkylation, dry reforming, carbon formation, and an additional cracking reaction was added by Lind et al [14].…”

Techno-economic assessment of biomass-to-ethanol by indirect fluidized bed gasification: Impact of reforming technologies and comparison with entrained flow gasification

“…In the present study, it is considered that simultaneous catalytic reforming of tars and hydrocarbons takes place in a reactor resembling a FCC unit, with continuous regeneration of the catalyst using air [1,11,24]. The main challenge of this option is to achieve high conversion of tars and light hydrocarbons while facing up catalyst deactivation by carbon deposition, sulfur and other pollutants from the biomass (chlorine, alkali metals).…”

Internal tar/CH4 reforming in a biomass dual fluidised bed gasifier

“…The catalysts can be used as the secondary method, in downstream catalytic reactors [10,11], such as catalytic beds, monoliths and filters, or as the primary method, e.g. added directly in the fluidised bed gasifier as the bed material.…”

“…The catalyst is usually deactivated in a gasification reactor due to carbon deposition, chloride, sulphur poisoning, oxidation and sintering. However, the lifetime of the catalyst can be prolonged by the oxygen balance in a dual fluidised bed gasifier (DFBG) [11,12].…”