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Enhancing the contact or interaction between cellulose and solid catalyst is a significant aspect in its efficient catalytic conversion. Herein, mixed ball milling of cellulose and solid catalyst was presented to achieve this goal, and the promotion effect was measured by hydrolytic hydrogenation of cellulose to sugar alcohols (the platform compounds for biogasoline) with solid acid and commercial 5 wt % Ru/C in water. The effects of ball-milling modes, time, and reaction parameters were studied. The properties of cellulose and solid acid catalyst before and after treatment were also analyzed. The yield of sugar alcohols reached 90.3% at 463 K with amorphous zirconium phosphate and Ru/C (mixed ball-milling time of 2 h). This high yield of sugar alcohols achieved in the mixed ball-milling time of 2 h was 12 times faster than that by the single ball milling of 24 h under the same reaction conditions. It is ascribed to the enhanced contact between cellulose and catalyst, resulting in promoting cellulose depo...

Ni-Based catalysts using mixed oxides of Al2O3–SiO2, Al2O3–TiO2, TiO2–SiO2, and TiO2–ZrO2 as supports were evaluated for hydrotreatments using guaiacol as the model compound and characterized by N2...

Catalytic hydrodeoxygenation (HDO) of vegetable oils to renewable alkane-type biofuels has attracted more and more concern in recent years. However, the presently used catalysts were mainly focused on the sulfided CoMo and NiMo catalysts, which inevitably posed sulfur contamination in final products. Therefore, exploring nonsulfured catalyst for this processing is of fundamental importance, but it is still an open challenge. In this paper, we prepared the sulfur free Ni supported on SiO2, γ-Al2O3, SAPO-11, HZSM-5, and HY by incipient wetness impregnation and tested the catalytic performance in HDO of methyl palmitate. Alkanes with long carbon chains were mainly produced with two possibly parallel approaches: hydrogenation of hexadecanal to hexadecanol, followed by dehydration/hydrogenation to C16 alkane and decarbonylaton/decarboxylation of hexadecanoic acid to C15 alkane. The acidity of catalysts significantly influenced their catalytic performance, and the Ni/SAPO-11 catalysts with weak and medium acidi...

A pilot-scale biomass-gasification-reforming system (feedstock of 150−300 kg/h, on a dry basis) was established to produce synthesis gas for liquid fuel synthesis. The design and operation of this system were preliminarily discussed. Reforming of biomass raw fuel gas over NiO−MgO/γ-Al2O3/cordierite monolithic catalysts was investigated in a multi-tube reformer. The anti-coking and anti-sintering properties of NiO−MgO/γ-Al2O3/cordierite monolithic catalysts were characterized. The results showed that the NiO−MgO/γ-Al2O3/cordierite monolithic catalyst with a pore channel size of 7 × 7 mm could continuously deal with biomass raw fuel gas containing large amounts of fly ash. No channel blocking was observed for a long time running. The pressure drop of the reformer was only below 700 Pa even under the conditions of fuel gas velocity of 1.4 m/s and fly ash content of 330 g N−1 m−3 in the raw fuel gas. The synthesis gas [H2 + CO > 60 vol %, H2/CO ratio = 0.9−1.0, and lower heating value (LHV) > 10 MJ N−1 m−3] c...

Preparation of emulsions from aqueous fractions of biomass pyrolysis liquid (bio-oil) and 0# diesel was studied under ultrasonic power. The thermogravimetric analysis and combustion characteristics of the optimized emulsions in a particular diesel generator were also investigated. The results show that the mass ratio of aqueous bio-oil fraction to 0# diesel affected the emulsion stability greatly, by factor analysis method, and the optimized emulsion was not stratified for 30 days when the ratio was 1:9 under the following conditions: water:bio-oil mass ratio, 2:1; ultrasonic time, 120 min; formula emulsifier addition (Span-80:Tween-80:Tween-20:n-octanol ratio = 72:9:9:10, wt %), 3 wt % (which was longer than that prepared by mechanical agitation). The density and heat value of the nonstratified emulsions (after 30 days) were similar with those of 0# diesel, because of the low aqueous bio-oil fraction content and 0# diesel dilution; however, an increase of more than 38.4% in the dynamic viscosity and a de...

Two types of SiO2 with different mesopore size and HZSM-5 zeolite were used to prepare hybrid supported cobalt-based catalysts. The textual and structural properties of the catalysts were studied using N-2 physisorption, X-ray diffraction (XRD), and H-2 temperature-programmed reduction (TPR) techniques. Fischer-Tropsch synthesis (FTS) performances of the catalysts were carried out in a fixed-bed reactor. The combination effects of the meso- and micropores of the supports as well as the interaction between supports and cobalt particles on FTS activity are discussed. The results indicate that the catalyst supported on the tailor-made SiO2 and HZSM-5 hybrid maintained both meso- and micropore pores during the preparation process without HZSM-5 particles agglomerating. The mesopores provided quick mass transfer channels, while the micropores contributed to high metal dispersion and accelerated hydrocracking/hydroisomerization reaction rate. High CO conversion of 83.9% and selectivity to gasoline-range hydrocarbons (C-5-C-12) of 55%, including more than 10% isoparaffins, were achieved simultaneously on this type of catalyst.

Solid acid 40SiO2/TiO2−SO42- and solid base 30K2CO3/Al2O3−NaOH were prepared and compared with catalytic esterification activity according to the model reaction. Upgrading bio-oil by solid acid and solid base catalysts in the conditioned experiment was investigated, in which dynamic viscosities of bio-oil was lowered markedly, although 8 months of aging did not show much viscosity to improve its fluidity and enhance its stability positively. Even the dehydration by 3A molecular sieve still kept the fluidity well. The density of upgraded bio-oil was reduced from 1.24 to 0.96 kg/m3, and the gross calorific value increased by 50.7 and 51.8%, respectively. The acidity of upgraded bio-oil was alleviated by the solid base catalyst but intensified by the solid acid catalyst for its strong acidification. The results of gas chromatography−mass spectrometry analysis showed that the ester reaction in the bio-oil was promoted by both solid acid and solid base catalysts and that the solid acid catalyst converted volat...

Biomass synthesis gas production via co-reforming of biogas and H2-rich syngas produced by biomass air−steam gasification has been investigated in a bubbling bed biomass gasifier with a NiO−MgO catalyst packed in a downstream reactor. The composition of synthesis gas was adjusted by a co-reforming reaction to meet the desired stoichiometric factor. The H2/CO ratio of biomass synthesis gas is above 1.5. It contains trace CH4 and CO2. The feeding rate of biogas depends on the composition and flow velocity of the H2-rich syngas produced in the gasifier. Compared with the commercial nickel-based reforming catalyst Z409R, the NiO−MgO catalyst exhibits better catalytic activity and anti-coke ability at high temperature (>750 °C). Compared with conventional pathways for adjustment of the stoichiometric factor, the method of co-reforming with addition of biogas is simple and highly efficient for nearly complete utilization of the carbon contained in the biomass.

Cracking of biomass tar was investigated over Ni/dolomite catalyst prepared by the incipient wetness method using modified dolomite as precursor. Modified dolomite was prepared by mixing Fe2O3 powd...

An apparatus for the fast pyrolysis of biomass is designed and set up to simulate the fast heating rate in the fluidized bed. The features of biomass fast catalytic pyrolysis in the apparatus are studied, whereas the kinetics model of biomass catalytic pyrolysis is presented. The results show that both calcined dolomite and a nickel-based catalyst can elevate the hydrogen content greatly. The nickel-based catalyst has a stronger effect, and the hydrogen content is almost doubled. The content of methane (CH4) can be greatly reduced through the use of nickel-based catalysts. Calcined dolomite can also decrease the content of CH4, to a smaller extent. A simplified model is presented, in which the entire process is treated as a single reaction. It assumes that biomass first decomposes to gaseous products, tars, and chars via three competitive reactions and then tars go through a second cracking reaction to produce gases and chars. Through the proposed model, the calculated data fit well with the experimental ...

With the use of dolomite in the fluidized-bed gasifier and the use of nickel-based catalysts in the fixed bed reactor downstream from the gasifier, the characteristics of hydrogen yield from biomass are investigated in the present study. Some calcined dolomite is placed initially in the gasifier with an amount of 120 g/(kg h-1) biomass. To replace the eroded and elutriated dolomite, calcined dolomite (0.3−0.45 mm) is continuously fed and its feeding rate is determined by preliminary test. The influence of the operating conditions in the catalytic reactor on the production of gases, especially H2, is studied over the temperature range of 650−850 °C, for weight hourly space velocity (WHSV) in the range of 2.68−10.72 h-1. In the gaseous product, the average content of H2 exceeds 50 vol %; C2 content is lowered to below 1 vol %, and nearly half of CH4 is converted after the catalytic reactor. Over the ranges of experimental conditions examined, the highest gas yield reaches 3.31 Nm3/kg biomass, wet basis; the...