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Purification and crystallization of xylitol from fermentation broth of corncob hydrolysates

Jinchao WEI, Qipeng YUAN, Tianxin WANG, Le WANG,

《化学科学与工程前沿（英文）》 2010年第4卷第1期页码 57-64 doi: 10.1007/s11705-009-0295-1

摘要： Xylitol, a five-carbon sugar alcohol, is a valuable sugar substitute, and widely used in the pharmaceutical, odontological and food industry due to its interesting properties. In the past decades, the xylitol industry has grown rapidly and more attention has been focused on xylitol purification, which possesses an important proportion of the whole industry. In our paper, the purification and crystallization of xylitol fermentation broth by biotechnology using corncob hydrolysates as substance were studied. An initial xylitol fermentation broth was decolored with activated carbon (1% M-1, 60°C, 165rpm), desalted with a combination of two ion-exchange resins (732 and D301), and residual sugars were separated with UBK-555(Ca). Then the solution was vacuum-concentrated up to supersaturation (750g/L xylitol). After adding 1% xylitol crystal seeds, the supersaturated solution was cooled to −20°C for 48h. The crystalline xylitol of a regular tetrahedral shape with purity 95% and crystallization yield 60.2% was obtained from the clarified xylitol fermentation broth. An intact, economical and environmental-friendly route of purification and crystallization of xylitol from fermentation of corncob hydrolysates was obtained, and its experimental procedure and data provided a sound basis for large-scale industrial production.

关键词： ion-exchange activated supersaturation tetrahedral substitute

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Upgrading of derived pyrolysis vapors for the production of biofuels from corncobs

Liaoyuan Mao, Yanxin Li, Z. Conrad Zhang

《化学科学与工程前沿（英文）》 2018年第12卷第1期页码 50-58 doi: 10.1007/s11705-017-1685-4

摘要： A bubbling fluidized bed pyrolyzer was integrated with an honeycomb as a catalytic upgrading zone for the conversion of biomass to liquid fuels. In the upgrading zone, zeolite coated ceramic honeycomb (ZCCH) catalysts consisting of ZSM-5 (Si/Al=25) were stacked and N or recycled non-condensable gas was used as a carrier gas. Ground corncob particles were fast pyrolyzed in the bubbling bed using fine sand particles as a heat carrier and the resulting pyrolysis vapors were passed on-line over the catalytic upgrading zone. The influence of carrier gas, temperature, and weight hourly space velocity (WHSV) of catalyst on the oil product properties, distribution and mass balance were studied. Using ZCCH effectively increased the hydrocarbon yield and the heating value of the dry oil, especially in the presence of the recycled noncondensable gas. Even a low usage of zeolite catalyst at WSHV of 180 h was effective in upgrading the pyrolysis oil and other light olefins. The highest hydrocarbon (≥C2) and liquid aromatics yields reached to 14.23 and 4.17 wt-%, respectively. The undesirable products including light oxygenates, furans dramatically decreased in the presence of the ZCCH catalyst.

关键词： corncob monolith upgrading pyrolysis