Advanced Materials Research Vols. 634-638

Abstract: A series of Ti(SO4)2/γ-Al2O3 catalysts were prepared by impregnation method and the catalytic performance of these catalysts in 1-butene oligomerization was investigated. The heat treatment temperature played great influences on the catalytic performance of these catalysts in the oligomerization. 90.1 wt.% conversion of 1-butene and 92.2 wt.% selectivity of dimers were obtained on Ti(SO4)2/γ-Al2O3(450) catalyst at 80 °C, 1.0 Mpa and LHSV=0.6 h−1. The heat treatment temperature determined the crystallinity of TiOSO4 and specific surface area of these catalysts, which affected the catalytic performance of these catalysts in 1-butene oligomerization. In addition, the physicochemical properties of these catalysts were comparatively characterized by powder X-ray diffraction (XRD), N2 isothermal adsorption-desorption techniques.

Abstract: A dynamical behavior about preparation polyketone from Carbon monoxide and ethene alternately copolymerization in methanol by catalyst cantained palladium acetate and DPPP was detailed represented in this paper. The synthesis mechanism of PK has been studied detailed, and a kinetic model equation is established, and the model parameter was determination. The product(PK) is not strictly alternating copolymerization, and their molecule chain cantained main -(CH₂CH₂CO)n-, and presence of a small amount of -CH₂CH₂CH₂CH₂CO-. The results showed that dynamical equation of the CO/C₂H₂ copolymerization to PK have corresponded with experiment data very well. In other words the kinetic equation of CO/C₂H₂ alternate copolymerization by Pd(AeO)/DPPP catalyst can used to describe their reaction behavior.

Abstract: How to dispose large amounts of free fatty acids of the desilked silkworm (Bombyx mori L.) pupae oil in a suitable way have attracted considerable attention. The feasibility of biodiesel production from the desilked silkworm pupae oil using Na₂O•SiO₂•5H₂O as a solid base catalyst was investigated, and the experimental conditions (i. e. molar ratio of methanol to oil, catalyst concentration, reaction time and reaction temperature) were studied. The experimental results indicated that Na₂O•SiO₂•5H₂O possesses high catalytic activity towards the synthesis of biodiesel from the desilked silkworm pupae oil. The methyl esters conversion of up to 73 % for free fatty acids of the desilked silkworm pupae oil was achieved using the following reaction conditions: catalyst concentration 5 %, the molar ratio of methanol to oil 6:1, reaction temperature 70 °C, and retention time 8 h. Therefore, the desilked silkworm pupae oil is proved to be a new biodiesel source in a more sustainable way.

Abstract: The objective of this study was to provide background date on rice straw pyrolysis in molten KCl(40mol%)-LiCl(60mol%). The effects of pyrolysis temperatures and sweep gas flow rates on the pyrolysis products yields and their chemical compositions were studied. The temperatures of pyrolysis and sweep gas flow rates were varied in the range of 380°C -540°C and 60L/h-260L/h, respectively. The compositions of gaseous products were analyzed by gas chromatography, and that of bio-oil obtained was investigated using gas chromatography-mass spectroscopic(GC-MS) technique. The yield of gaseous products increases with the increasing temperature, the char yield has demonstrated a downtrend, and the maximum yield of bio-oil is up to 15.43 wt.% at 460°C. The yield of char decreases with the sweep flow rate, the gaseous has a minimum yield at 100L/h, and the maximum yield of bio-oil is 15.43wt.% at 100L/h .The main gaseous products are CO, CO2 , H2 and CH4. Ketones and phenols are the main compounds in the bio-oil, the presence of molten inhabites their formation, and promotes the production of furfural. The bio-oil attained from pyrolysis is a potential source of renewable fuel and chemical feedstock.

Abstract: The release of alkali species can cause of severe problem of hot corrosion during gasification especially at high temperature and pressure. The direct use of coal may harmful for power plants. The aim of work to obtained comprehensive knowledge prior utilization of coal. Therefore, thermodynamic equilibrium calculations were performed by Fact Sage 5.2 and simulated the gasification environment at elevated temperature and pressure. Four hard and soft Chinese coal such as Yungui (Vad<6.6%), Xiao Tun(Vad<11.1), Datong (Vad <23.18), Ping Zhuan (Vad<31.84) ,and Saw dust (Vad<68.80) and Saw dust char (Vad<3.39) belongs to anthracite, Sub-bituminous, lignite, biomass and biomass char were selected and releasing order was calculated by plotting mole fraction of each species Vs temperature (1000 to 1400°C) at 1 bar and VS pressure (5 to 15bar ) at 1000°C. On the basis of predicted releasing order the H2S species can be predicted most stable species for gasification at elevated temperature and pressure. The high released amount of SO2, H2S, NaCl, KCl and HCl was obtained for YUN, DAT,SAD and SADChar at (1400°C-1000°C) temperature and (15-5bar) pressure. Comparing with high pressure the predicted release of KCl and HCl was observed higher but SO2, H2S, and NaCl release was found lower than elevated temperature during combustion process. The above available predicted information is valuable for development of hot gas cleaning technology.

Abstract: Desorption rate curves of n-pentane on 5A zeolites at 418 K and 10-0.03 kPa were determined, and the effects of different macropore structure on desorption performance were analyzed. Results show that macropore distribution of 5A-1 concentrates in 0.25-1.25 μm, while that of 5A-2 ranges from mesopore category to 0.3 μm, but 5A-3 contains both pores of 0.01-0.1 μm and 0.2-2 μm inside, reflecting a broadest distribution; 5A-3, 5A-1 and 5A-2 reach desorption equilibrium after 1100 s, 1400 s and 2000 s respectively at 0.03 kPa, indicating that abundant macropores make n-pentane fastest desorbed from 5A-3, but this advantage gradually disappears with the increasing pressure; the effective desorption diffusion coefficients of n-pentane on 5A-1, 5A-2 and 5A-3 are 4.2×10-15-2.2×10-14 m2/s, 2.0×10-15-2.3×10-14 m2/s, 7.4×10-15-2.4×10-14 m2/s respectively, suggesting that plenty macropores make the diffusivity less affected by the changes of pressure, which can guarantee a fast diffusion rate of n-pentane even at low pressure.

Abstract: Equilibrium adsorption capacity and adsorption rate of n-hexane on 5A zeolites(A-1~A-3) were measured by gravimetric method. The carbon depositions after intensification were studied by TG-DTA. Results show that secondary pores of A-1~A-3 distribute in 0.01~0.5μm, 0.05~5μm, 0.01~0.05μm. A-3 has the minimum average pore size and pore volume .The diffusion time constant of n-hexane on A-1 and A-3 are 4.004×10^-4, 2.038×10^-4 s^-1, are 14.8 and 7.5 times that on A-2, respectively. The decay rate of n-hexane adsorption capacity and the coke deposition amount on A-1 are 28% and 0.06% less than these on A-2, while the both on A-3 are the smallest (41% and 6.67%), after five times intensification under industrial hexane at 400 °C. Appropriate adjustment of secondary pores of 5A zeolites, to raise the proportion of the pores about 0.01 ~ 0.05μm, can improve diffusion rate of adsorbates, adsorption stability and service life of 5A zeolites.

Abstract: In this paper, the desulphurization of coals prepared briquettes using lime based products (calcium hydroxide and calcium carbonate) and sodium hydroxide as desulphurizing agents (DSA) was investigated in a vertically integrated experimental furnace. Meanwhile, the effect of sodium hydroxide on the denitrification was also studied. The results indicated that calcium carbonate as a DSA is more efficient for SO₂ removal during the char combustion, whereas hydrated lime and NaOH are efficient in both char and volatile combustion. For most of the coals, the desulfurization efficiencies in case of lime hydrated reaches over 80 %, whereas desulfurization efficiencies is below 70% when calcium carbonate is used as DSA. It was also found that NaOH can be used as denitrifying agent as well as desulphurizing agent, and the maximum denitrifying efficiencies by using NaOH denitrifying agents for coal A and coal B are 59% and 54%, respectively.

Abstract: The success of CO₂ capture from flue gas with solid sorbent is dependent of a low cost sorbent with high CO₂ adsorption capacity and selectivity. Modifying surface texture of activated carbon with impregnating amines is expected to offer the benefits of liquid amines in the typical adsorption process routes. In this work, cocoanut activate carbon (AC) is firstly alkalified by KOH solution, then modified by impregnation of tetraethylenepentamine (TEPA), triethylenetetramine (TATA), and triethanolamine (TEA) to form a new type of sorbents. The effects of alkalifying treatment and temperature on CO₂ adsorption capacities of the sorbents are investigated. Results indicate that the activate carbons modified by combining alkalification pretreatment firstly and then impregnated amines at low temperature are profitable for CO₂ adsorption. The adsorption capacities of CO₂ are enhanced with TEPA and TETA impregnation on the activate carbon pretreated by KOH solution. And CO₂ adsorption capacity of new sorbents is stable after many adsorption and desorption cycles.

Abstract: The removal of sulfides (e.g., benzothiophenes) in FCC diesel fuel is the most important issue. Here, sulfides were removed by catalytic oxidation them into sulfones by H₂O₂-formic acid and solvent extraction induced by ultrasound irradiation. The introduction of ultrasound provides energy for the oxidation reaction, which can assure a complete oxidative desulfurization for sulfides in diesel oil. The effects of extraction solvent, extraction duration, ratio of extractant over extraction times, and oil over extraction times were investigated. Under the optimum condition, the removal efficiency of sulfur compounds and the recovery of the product can amount to 94.2% and above 90%, respectively.