Deactivation of a Ni-Based Reforming Catalyst During the Upgrading of the Producer Gas, from Simulated to Real Conditions

Abstract

The deactivation of a nickel reforming catalyst during the upgrading of the producer gas obtained by gasification of lignocellulosic biomass was studied. The research involved several steps: the selective deactivation of the catalyst in a laboratory scale; the streaming of the catalyst with the producer gas of a downdraft and an oxygen/steam circulating fluidized bed (CFB) gasifier; and tests in a reformer placed in a slipstream of the CFB gasifier. The information obtained allowed to elucidate the catalyst deactivation mechanisms taking place during the reforming of the producer gas: physical deactivation by deposition of fine ashes, aerosol particulate or carbon; poisoning by H 2 S and HCl present in the gas phase and thermal sintering because of the high operation temperatures required to avoid the chemical deactivation. These physical and chemical effects depended on the composition of the biomass fuel.

Modeling of soot formation during partial oxidation of producer gas

“…Many alternatives are available and have been the focus of much research, such as steam reforming, (SR), autothermal reforming, (ATR) and catalytic partial oxidation, (CPO). The main problem with the mentioned techniques is that they rely on catalysts which are highly susceptible to sulfur poisoning [11][12][13][14]. Although much research has been devoted to finding suitable catalysts for this area no clear alternative has yet emerged.…”

Catalytic activities and resistance to poisoning of tar reforming catalysts for syngas upgrading

“…X-ray photoelectron spectroscopy (XPS) also indicated that Ni 0 peak was shifted to higher values (853.4 eV from 852.5 eV) which was ascribed to the different chemical environment of Ni 0 from the presence of Ni7S6. Ni (211), determined that both surfaces are prone to sulfidation due to the low energy barrier [114]. The studied reaction products (i.e.…”

“…As detailed in Chapter 2, the effectiveness of Ni catalysts has also been limited as they can be easily deactivated due to the presence of impurities. Sulfur compounds such as H2S and COS, and halide compounds such as HCl represent some of the syngas impurities that have a detrimental effect on Ni catalyst performance, poisoning reforming as well as water-gas shift (WGS) activities of Ni-based catalysts [31,32,92,131,143,144,211,212]. Halogen species, such as HCl, chemisorbs onto the active Ni sites forming NiX2 complexes (X = halogen).…”

“…Halogen species, such as HCl, chemisorbs onto the active Ni sites forming NiX2 complexes (X = halogen). Studies have shown that HCl has a detrimental effect on reforming activity [211], and to a larger extent, WGS activity [21,32,88].…”

“…The thermal treatment of waste containing BFRs results in the release of HBr [54][55][56][57], which can influence the activity of reforming catalysts. While there are reports describing the influence of HCl on catalytic activity during tar reforming [21,32,88,211], the effects of HBr have not been investigated. The effective strategy to overcome the detrimental effect of HBr was also investigated, by employing catalysts with different composition, structure and strength of metalsupport interaction.…”