Yan Yong-jie

Comparison of effect of ferric sulfide catalyst and nickel sulfide on coliquefaction of coal and biomass

Abstract Coliquefaction of coal and sawdust in the presence of catalysts was studied under cold hydrogen pressure from 2.04 to 4.76 MPa in the temperature range of 300–400 °C. In terms of overall conversion, yields and increment values from comparisons, investigations were made on catalysts of the sulfides of Fe, Ni and Cu and the methods of catalyst preparation. As economics of the technological process is concerned, a catalyst of ferric sulfide is preferred, apart from its advantages over the catalyst of nickel sulfides in catalytic effects under three sets of reaction conditions from our experiments. The optimal operation conditions were concluded for the preferred catalyst FeS x .

Hydrogen production from glycerol steam reforming over Ni/La/Co/Al2O3 catalyst

ABSTRACT Hydrogen production by steam reforming reaction of glycerol over Co/La/Ni-Al2O3 was studied in tubular fixed-bed reactor. The influences of operating parameters such as temperature, steam/carbon ratio, and weight hourly space velocity (WHSV) on hydrogen yield and carbon conversion were examined under atmospheric pressure. The results showed that carbon conversion increased with the increase of temperature and steam-to-carbon mole ratio (S/C). At 700°C, S/C=3:1, and WHSV=2.5h−1, hydrogen yield and potential hydrogen yield were up to 77.64% and 89.64%, respectively; meanwhile, the carbon conversion reached 96.36%.

Hydrogen production by glycerol reforming in a fixed-bed reactor

ABSTRACT Hydrogen production from the steam-reforming reaction of glycerol was studied over charcoal as catalyst in a tubular fixed-bed reactor. The results showed that charcoal was a novel kind of catalyst, which not only had an active effect on the reforming process, but can decrease the cost of production. The optimum conditions were obtained at 800°C, S/C of 4, WHSV of 1.5 h−1. Hydrogen yield and potential hydrogen yield were up to 75.12% and 84.31%, as well as the carbon conversion reached 89.08% at the optimum conditions. The results of SEM and TGA indicated that there was polymerization and polycondensation of glycerol still in steam-reforming process.

Analysis of coke precursor on deactivated catalyst in bio-oil upgrading process.

ABSTRACT Characterization of coke precursor on deactivated catalyst in bio-oil upgrading under CO atmosphere was analyzed with thermogravimetry, X-ray diffraction, infrared analysis, scanning electron microscopy, and nuclear magnetic resonance. The results showed that the deposition of coke precursor on a catalyst surface was mainly low-boiling point of saturated hydrocarbon compounds and the coke precursor of internal channels of deactivated catalyst were major aromatic hydrocarbon compounds. The coke precursor was in an amorphous state, which was highly dispersed on the catalyst surface or into the catalyst micropore. In addition, the catalyst deactivation mechanism was speculated that the small molecule aromatic compounds entered the internal channels of a catalyst and formed macromolecular aromatic hydrocarbons by aromatization gradually, further condensed to form coke and obstructed the channels of the catalyst.

Acid pretreatment of bagasse pith at low temperature with steam-assisted heating

In this paper, dilute acid pretreatment of bagasse pith was investigated at low temperature. Process parameters varied including mass ratio of liquid to solid (r = 6:1–12:1 l/kg), reaction temperature (T = 100 °C–130 °C), and acid concentration (c = 0.75 wt. %–1.5 wt. %) in order to effectively transform hemicellulose to fermentable sugar to improve the utilization of bagasse pith. The effects of dilute acid pretreatment were evaluated by fermentable sugar yield and decomposition products concentration. The optimum pretreatment conditions for depolymerization of hemicellulose bagasse pith was obtained at r = 10:1 l/kg, T = 120 °C, c = 1.0 wt. %, t = 16 min. From this paper, it could be concluded that dilute acid pretreatment can be successfully applied to bagasse pith to achieve high yield of xylose (84.41%) with acceptable levels of fermentation inhibitors formation.

DEVELOPMENT OF A NEW TYPE OF LOW-TEMPERATURE PATTERN WAX

The effects of several important components on casting waxes, such as low-melting point petroleum waxes, high-melting point waxes, stearic acid and additive 201 were investigated. A new type of LPW low-temperature pattern wax was developed by method of cooling curve. The experimental results showed that stearic acid and No. 56 petroleum wax could lower the casting temperature. No. 80 microcrystalline wax, No. 85 microcrystalline wax and additive 201 all could make the pattern wax crystal construction finer, although additive 201 was more effective than the microcrystalline waxes. The application tests showed that LPM pattern waxes were higher quality pattern waxes such as better gloss, higher rigidity and higher intensity than the original common low casting temperature pattern waxes.

DEVELOPMENT OF OXIDIZED POLYETHYLENE WAXES

ABSTRACT A method of preparation of oxidized polyethylene waxes, which have many applications such as in plastics, rubber, leather, paper, inks and textile, etc. was developed. The experiments of polyethylene waxes oxidization were carried out in a pilot plant. The reactor was a 0.27 m diameter and 3 m high column reactor with a conical distribution plate. The experimental results showed that the optimal conditions for preparation of the Oxidized Polyethylene Waxes were: catalyst KMnO4, reaction temperature 141—148°C, reaction time 3-7 h, air velocity 4—8 m/s. The oxidized polyethylene waxes with acid number of above 30 mgKOH/g could be obtained with this method.