The oxidant-free dehydrogenation of n-pentanol over copper based catalysts was investigated in this paper.The effect of metal modification on the activity and stability of the copper catalyst supported onγ-Al_(2)O_(3...The oxidant-free dehydrogenation of n-pentanol over copper based catalysts was investigated in this paper.The effect of metal modification on the activity and stability of the copper catalyst supported onγ-Al_(2)O_(3)and La_(2)O_(3)(Cu/γ-Al_(2)O_(3)-La_(2)O_(3))was clarified and a Cr modified Cu/Al_(2)O_(3)-La_(2)O_(3)(Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3))showed the best catalytic performance.The conversion of n-pentanol was 70.0%and the selectivity for n-pentanal increased to 97.1%over Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3).X-ray diffraction and temperature programmed reduction of H2 indicated that the addition of Cr favors the formation and reduction of the copper oxide,and the dispersion of the active Cu^(0) species,accounting for the good activity and stability of this catalyst.Furthermore,the lower amount of acidic sites in Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3)is suggested to suppress the dehydration in oxidant-free dehydrogenation of n-pentanol,accounting for the higher selectivity for n-pentanal.展开更多
为了揭示含氧燃料与喷油策略耦合对发动机燃烧、性能和排放特性影响的机制,基于三维仿真软件CONVERGE,耦合化学反应动力学机理,研究了正戊醇—柴油混合燃料在不同喷射策略下燃烧与有害排放物的生成过程。结果表明,正戊醇促进了燃烧过程...为了揭示含氧燃料与喷油策略耦合对发动机燃烧、性能和排放特性影响的机制,基于三维仿真软件CONVERGE,耦合化学反应动力学机理,研究了正戊醇—柴油混合燃料在不同喷射策略下燃烧与有害排放物的生成过程。结果表明,正戊醇促进了燃烧过程,燃用正戊醇—柴油混合燃料时,缸内最高燃烧压力和燃烧放热峰值增大,发动机平均指示压力(indicated mean effective pressure,IMEP)升高,CO、总碳氢化合物(total hydrocarbons,THC)和碳烟排放降低,但NO_(x)排放升高。采用大比例预喷射策略可以促进主喷燃烧过程,提高缸内温度,增大IMEP,但导致CO及THC排放升高,而小预喷间隔会导致碳烟排放增加。后喷射策略导致发动机IMEP降低,但可以降低NO_(x)排放。在小后喷间隔下碳烟排放显著降低,但在大后喷间隔下碳烟排放明显升高。研究表明,正戊醇柴油混合燃料采用大预喷间隔及小后喷间隔的3次喷油策略,能够获得最高的IMEP及最低的有害物排放。展开更多
Long-chain alcohols were considered to be promising alternative fuels and fuel additives. This study was aimed at figuring out the influences of blending long-chain alcohols with jet fuel on the macroscopic spray char...Long-chain alcohols were considered to be promising alternative fuels and fuel additives. This study was aimed at figuring out the influences of blending long-chain alcohols with jet fuel on the macroscopic spray characteristic. n-Butanol and n-pentanol were chosen as tested alternative fuels. A common-rail injection system was used to create high-pressure injection conditions. The Schlieren imaging system was used to capture spray processes. Results showed that with the addition of long-chain alcohols, the spray tip penetration and the peak spray tip velocity increased, whereas the spray cone angle and the spray area decreased. Comparisons between those macroscopic spray characteristics of AKB blends and AKP blends were also conducted. Compared to AKB blends, AKP blends showed similar spray tip penetration, larger peak tip velocity, smaller spray cone angle, and smaller spray area.展开更多
基金Financial support by the National Natural Science Foundation of China(Nos.20806018 and 21376060)the Natural Science Foundation of Hebei Province(Nos.B2011201017 and B2014201024)are gratefully acknowledged.
文摘The oxidant-free dehydrogenation of n-pentanol over copper based catalysts was investigated in this paper.The effect of metal modification on the activity and stability of the copper catalyst supported onγ-Al_(2)O_(3)and La_(2)O_(3)(Cu/γ-Al_(2)O_(3)-La_(2)O_(3))was clarified and a Cr modified Cu/Al_(2)O_(3)-La_(2)O_(3)(Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3))showed the best catalytic performance.The conversion of n-pentanol was 70.0%and the selectivity for n-pentanal increased to 97.1%over Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3).X-ray diffraction and temperature programmed reduction of H2 indicated that the addition of Cr favors the formation and reduction of the copper oxide,and the dispersion of the active Cu^(0) species,accounting for the good activity and stability of this catalyst.Furthermore,the lower amount of acidic sites in Cu-Cr/γ-Al_(2)O_(3)-La_(2)O_(3)is suggested to suppress the dehydration in oxidant-free dehydrogenation of n-pentanol,accounting for the higher selectivity for n-pentanal.
文摘为了揭示含氧燃料与喷油策略耦合对发动机燃烧、性能和排放特性影响的机制,基于三维仿真软件CONVERGE,耦合化学反应动力学机理,研究了正戊醇—柴油混合燃料在不同喷射策略下燃烧与有害排放物的生成过程。结果表明,正戊醇促进了燃烧过程,燃用正戊醇—柴油混合燃料时,缸内最高燃烧压力和燃烧放热峰值增大,发动机平均指示压力(indicated mean effective pressure,IMEP)升高,CO、总碳氢化合物(total hydrocarbons,THC)和碳烟排放降低,但NO_(x)排放升高。采用大比例预喷射策略可以促进主喷燃烧过程,提高缸内温度,增大IMEP,但导致CO及THC排放升高,而小预喷间隔会导致碳烟排放增加。后喷射策略导致发动机IMEP降低,但可以降低NO_(x)排放。在小后喷间隔下碳烟排放显著降低,但在大后喷间隔下碳烟排放明显升高。研究表明,正戊醇柴油混合燃料采用大预喷间隔及小后喷间隔的3次喷油策略,能够获得最高的IMEP及最低的有害物排放。
基金supported by the National Natural Science Foundation of China(No.51376171)
文摘Long-chain alcohols were considered to be promising alternative fuels and fuel additives. This study was aimed at figuring out the influences of blending long-chain alcohols with jet fuel on the macroscopic spray characteristic. n-Butanol and n-pentanol were chosen as tested alternative fuels. A common-rail injection system was used to create high-pressure injection conditions. The Schlieren imaging system was used to capture spray processes. Results showed that with the addition of long-chain alcohols, the spray tip penetration and the peak spray tip velocity increased, whereas the spray cone angle and the spray area decreased. Comparisons between those macroscopic spray characteristics of AKB blends and AKP blends were also conducted. Compared to AKB blends, AKP blends showed similar spray tip penetration, larger peak tip velocity, smaller spray cone angle, and smaller spray area.
