Lixia Yuan

Hydrogen Production by Low-temperature Steam Reforming of Bio-oil over Ni/HZSM-5 Catalyst

We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregnation method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst composition, reforming temperature and the molar ratio of steam to carbon fed on the stream reforming process of bio-oil over the Ni/HZSM-5 catalysts were investigated in the reforming reactor. The promoting effects of current passing through the catalyst on the bio-oil reforming were also studied using the electrochemical catalytic reforming approach. By comparing Ni/HZSM-5 with commonly used Ni/Al2O3 catalysts, the Ni20/ZSM catalyst with Ni-loading content of about 20% on the HZSM-5 support showed the highest catalytic activity. Even at 450 °C, the hydrogen yield of about 90% with a near complete conversion of bio-oil was obtained using the Ni20/ZSM catalyst. It was found that the performance of the bio-oil reforming was remarkably enhanced by the HZSM-5 supporter and the current through the catalyst. The features of the Ni/HZSM-5 catalysts were also investigated via X-ray diffraction, inductively coupled plasma and atomic emission spectroscopy, hydrogen temperature-programmed reduction, and Brunauer-Emmett-Teller methods.

Design of Multiple Metal Doped Ni Based Catalyst for Hydrogen Generation from Bio‐oil Reforming at Mild‐temperature

A new kind of multiple metal (Cu, Mg, Ce) doped Ni based mixed oxide catalyst, synthesized by the co‐precipitation method, was used for efficient production of hydrogen from bio‐oil reforming at 250–500 °C. Two reforming processes, the conventional steam reforming (CSR) and the electrochemical catalytic reforming (ECR), were performed for the bio‐oil reforming. The catalyst with an atomic mole ratio of Ni : Cu : Mg : Ce : Al =5.6:1.1:1.9:1.0:9.9 exhibited very high reforming activity both in CSR and ECR processes, reaching 82.8% hydrogen yield at 500 °C in the CSR, yield of 91.1% at 400 °C and 3.1 A in the ECR, respectively. The influences of reforming temperature and the current through the catalyst in the ECR were investigated. It was observed that the reforming and decomposition of the bio‐oil were significantly enhanced by the current. The promoting effects of current on the decomposition and reforming processes of bio‐oil were further studied by using the model compounds of bio‐oil (acetic acid and ethanol) under 101 kPa or low pressure (0.1 Pa) through the time of flight analysis. The catalyst also shows high water gas shift activity in the range of 300–600 °C. The catalyst features and alterations in the bio‐oil reforming were characterized by the ICP, XRD, XPS and BET measurements. The mechanism of bio‐oil reforming was discussed based on the study of the elemental reactions and catalyst characterizations. The research catalyst, potentially, may be a practical catalyst for high efficient production of hydrogen from reforming of bio‐oil at mild‐temperature.

Effects of Current on Microcosmic Properties of Catalyst and Reforming of Bio-oil

Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming catalyst (NiO-Al2O3), where an AC electronic current passed through the catalyst bed. The promoting effects of current on the bio-oil reforming were studied. It was found that the performance of the bio-oil reforming was remarkably enhanced by the current which passed through the catalyst. The effects of currents on the microcosmic properties of the catalyst, including the Brunauer–Emmett–Teller (BET) surface area, pore diameter, pore volume, the size of the crystallites and the reduction level of NiO into Ni, were carefully characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscope. The desorption of the thermal electrons from the electrified catalyst was directly observed by the TOF (time of flight) measurements. The mechanism of the electrochemical catalytic reforming of bio-oil is discussed based on the above investigation.

Production of Hydrogen from Bio-oil Using Low-temperature Electrochemical Catalytic Reforming Approach over CoZnAl Catalyst

High-efficient production of hydrogen from bio-oil was performed by electrochemical catalytic reforming method over the CoZnAl catalyst. The influence of current on the hydrogen yield, carbon conversion, and products distribution were investigated. Both the hydrogen yield and carbon conversion were remarkably enhanced by the current through the catalyst, reaching hydrogen yield of 70% and carbon conversion of 85% at a lower reforming temperature of 500°C. The influence of current on the properties of the CoZnAl catalyst was also characterized by X-ray diffraction, X-ray photoelectron spectroscopy, thermal gravimetric analysis, and Brunauer-Emmett-Teller measurements. The thermal electrons would play an important role in promoting the reforming reactions of the oxygenated-organic compounds in the bio-oil.

Hydrogen Production From Crude Bio-oil and Biomass Char by Electrochemical Catalytic Reforming

We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield reached 110.9 g H2/kg dry biomass. The product gas was a mixed gas containing 72%H2, 26%CO2, 1.9%CO, and a trace amount of CH4. It was observed that adding biomass char (a by-product of pyrolysis of biomass) could remarkably increase the absolute H2 yield (about 20%-50%). The higher reforming temperature could enhance the steam reforming reaction of organic compounds in crude bio-oil and the reaction of CO and H2O. In addition, the CuZn-Al2O3 catalyst in the water-gas shift bed could also increase the absolute H2 yield via shifting CO to CO2.