BioEnergy Research
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2015
·Vol. 8
·期 3
·1263-1274
·
IF 3.541
Zhang Zhi-bo,Lu Qiang,Ye Xiao-ning,Wang Ti-peng,Wang Xian-hua,Dong Chang-qing
Solid phosphoric acid (SPA) catalysts with different carriers were prepared and used for catalytic fast pyrolysis of poplar wood to produce levoglucosenone (LGO), a valuable anhydrosugar derivative that can be used in various organic synthesis applications. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to evaluate the catalytic capabilities of these catalysts under different reaction conditions. The results indicated that SPA catalyst prepared with the SBA-15 carrier exhibited the best catalytic capability for selectively producing LGO. Both the catalytic pyrolysis temperature and catalyst-to-biomass ratio affected the pyrolytic products greatly. The maximal LGO yield reached as high as 8.2 wt% from poplar wood, obtained at the pyrolysis temperature of 300 °C and the catalyst-to-biomass ratio of 1. The by-products during the catalytic pyrolysis process were mainly acetic acid (AA) and furfural (FF). In addition, the SPA catalyst possessed better catalytic capability than the liquid phosphoric acid (H 3 PO 4 ) catalyst to produce LGO.
研究领域:
生物能源
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催化化学
·
生物质转化
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热解化学
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绿色化学
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可再生资源利用
✓ 已验证
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Guoqing Wang,Yuyang Li,Lei Li,Fei Qi
Cellular instability of spherically expanding methanol/air flames was investigated in a constant-volume single-chamber cylindrical combustion vessel at initial temperatures of 373–423 K, initial pressures of 1–10 atm and equivalence ratios of 0.7–2.1. Flame morphology shows that the methanol/air flames suffer from cellular instability, especially at 5–10 atm. Stability analysis was performed to determine the logarithmic growth rate of disturbance, the critical Peclet number and the critical flame radius. The influences of initial temperature, initial pressure and equivalence ratio on cellular instability were analyzed to identify the influential factors. Both experimental results and stability analysis indicate cellular instability monotonically increases with increasing temperature or pressure and non-monotonically varies with increasing equivalence ratio. The reduced critical Peclet number and flame thickness slightly destabilize the flame surface as temperature increases. The almost unchanged critical Peclet number and the greatly reduced flame thickness with increasing pressure make the critical flame radius smaller and the flame surface more unstable at high pressures. The monotonically decreased critical Peclet number and the non-monotonically varied flame thickness result in the non-monotonic variation of cellular instability in methanol/air flames versus equivalence ratio. The critical flame radius consequently increases with increasing equivalence ratio under very rich conditions, while the corresponding flame surface becomes more smooth. The non-monotonic variation of cellular instability versus equivalence ratio is anticipated to exist widely in combustion of heavy fuels .
研究领域:
燃烧学
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热力学
·
流体力学
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化学动力学
·
能源工程
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jizhen Zhu,Sixu Wang,Mohsin Raza,Yuan Feng,Jing Li,Yebing Mao,Liang Yu,Yong Qian,Xingcai Lu
Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process . It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO 2 while CH 3 OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.
研究领域:
燃烧化学
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燃料科学
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化学动力学
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内燃机工程
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替代燃料技术
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Rongrong Li,Jiaqi Weng,Cuihong Ye,Anguo Ying,Qizhong Zhou,Aiguo Zhong,Hao Chen,Jianguo Yang
The equilibrium solubility of sodium 2,4-diaminobenzene sulfonate in liquid mixtures (methanol + water, isopropanol + water, and 1,2-propanediol + water) were determined at temperatures ranging from (273.15 to 323.15) K. The solubility of sodium 2,4-diaminobenzene sulfonate increased with temperature increment but decreased with the concentrations of methanol, isopropanol or 1,2-propanediol in liquid mixtures. The obtained solubility data were correlated by Apelblat equation and Sun model. On the base of the measured solubility, the dissolution enthalpy ( Δ H sol o ) of the dissolution process were calculated.
研究领域:
药物化学
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物理化学
·
药剂学
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溶解行为研究
·
热力学
✓ 已验证
DOI
高影响因子
POLYMER
·
2015
·
IF 3.562
Xue Jiang,Chun Feng,Guolin Lu,Xiaoyu Huang
A homopolymer strategy was developed to synthesize temperature and pH/CO 2 stimulus-responsive homopolymers. A new class of acrylamide monomers bearing oligo(ethylene glycol) unit and N,N -diethylaminoethyl group were designed and prepared through Aza-Michael addition reaction followed by amidation with acryloyl chloride using amino group as a linkage to connect oligo(ethylene glycol), N,N -diethylaminoethyl, and polymerizable double bond groups together. Subsequently, the corresponding homopolymers containing oligo(ethylene glycol) unit and N,N -diethylaminoethyl group in each repeated unit were prepared via RAFT polymerization with controlled molecular weights and relatively narrow molecular weight distributions . The lower critical solution temperature (LCST) of homopolymer was examined to be influenced by molecular weight, salt concentration, and pH value of aqueous solution. The LCSTs of homopolymers could be tuned in a wide temperature window by changing pH value of aqueous solution and it increased with the decrease of pH value. Particularly, CO 2 gas as a unique pH stimulus can also reversibly adjust the solubility of homopolymer without the addition of acids or bases.
研究领域:
高分子化学
·
智能材料
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药物递送
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生物医用材料
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刺激响应材料
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Kai Wang,Guangzhen Li,Yanhong Li,Yuan Chen,Ling Zhang,Zhiying Zhu,Zhiyong Xu,Wenbo Zhao
In the present work, a kind of amine alkyl siloxane N -butyl-N-((1,1,3-trimethyl-3,3-diphenyldisiloxaneyl)methyl)butan-1-amine (BTDMBA) was synthesized and used to capture SO 2 . Its thermal decomposition temperature is 160℃, which is comparable with that of Ionic liquids (ILs), but its viscosity is only 125 mPa∙s at 25℃ after the absorption of SO 2 , which is much lower than that of ILs. The reaction mechanism is that BTDMBA reacted with SO 2 to form charge transfer complex BTDMBA∙SO 2 . The reaction enthalpy and entropy change are −83.95 kJ/mol and −240.48 J·mol −1 ·K −1 , respectively, which are more negative than that of ILs. By comparing the enthalpy and entropy change of amine alkyl siloxane and absorbents reported in literatures, an unexpected entropy enthalpy compensation phenomenon was discovered and the isokinetic temperature was found to be 371 K. Based on this phenomenon and the optimization objective function, it was also found that with the decrease of entropy change, the optimal absorption and desorption temperature difference increased initially and decreased afterwards. The maximum of entropy changes is −201 J·mol −1 ·K −1 for absorbent to achieve recycle absorption capacity 0.79 mol/mol under the condition of absorption pressure 0.002 bar and desorption pressure 1 bar.
研究领域:
物理化学
·
环境化学
·
分离科学
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能源材料
·
工业气体净化
·
绿色化工
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）