Saccharification of plant biomass by pyrolytic molecular distillation

通过热解分子蒸馏糖化植物生物质

基本信息

批准号：
15310046
负责人：
KUGA Shigenori
金额：
$ 9.54万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

For improving anhydrosugar (levoglucosan, LG) yield from thermal decomposition of cellulose, laser pyrolysis which can heat the material from its open surface. Minimum laser irradiation condition for causing fast pyrolysis was determined as : 75〜100W, pulse length more than 14 ms ; 150〜250W, pulse length more than 8 ms. Pyrolysis under vacuum caused significant generation of aerosol (white smoke), which remained for a long time and obstructed efficient recovery by trap. Flushing by atmospheric inert gases was effective in expelling the aerosol into cotton trap at exit. Maximum LG yield by this method was 20〜25%, max. 35%. Batch-type vacuum pyrolysis in glass bottle for comparison gave LG yield of 35〜56%. This variation was caused by the method of cold trapping, and close placing of trap to the heated area was found very important. Based on this finding, a novel pyrolyzer was designed and tested extensively. The apparatus consisted of a pair of metal belt conveyers, arranged parallel and facing with each other. The lower belt was heated to pyrolysis temperature from beneath, and the upper belt was cooled from above. The LG yield by this apparatus strongly depended on the vacuum level, and the low level of residual air was advantageous for higher yields. Optimal pressure was approx. 5 KPa, which gave maximum yield of 70% from pure cellulose and 50% from corn starch. The value for cellulose significantly exceeded the highest reported value of 55%. Since this pyrolyzer can operate continuously, it can be used for industrial production of LG from cellulose. As a side application of this pyrolyzer, thermal extraction of caffeine from coffee and green tea was attempted. The results showed high efficiency, i.e. approx. 80〜90% of caffeine was recovered from ground materials at 350℃ treatment. These results showed advantages of the novel pyrolyzer in extracting useful components from biomass materials.

为了提高纤维素热分解产生的脱水糖（左旋葡聚糖，LG）产率，激光热解可以从材料的开放表面加热材料，引起快速热解的最低激光照射条件确定为：75〜100W，脉冲长度大于14ms； 150～250W，脉冲长度大于8ms，真空下热解产生大量气溶胶（白色）烟），它保留很长时间并阻碍了通过大气惰性气体的有效回收，通过该方法将气溶胶排出到棉花捕集器中，最大LG产量为20-25％，最大35％。用于比较的玻璃瓶中的间歇式真空热解的LG产率为35-56%，这种变化是由冷捕集方法引起的，并且发现捕集器靠近加热区域。基于这一发现，我们首先设计并测试了一种新型热解器，该装置由一对平行且面对面布置的金属传送带组成，下传送带从下方加热至热解温度。该设备的 LG 产率很大程度上取决于真空水平，并且低残留空气水平有利于提高产率，最佳压力约为 5 KPa，最高产率可达 70%。纯纤维素和 50% 来自玉米淀粉。纤维素的值显着超过了报道的最高值 55%。由于该热解器可以连续运行，因此可以用于从纤维素中生产 LG。尝试从咖啡和绿茶中热提取咖啡因，结果显示效率很高，即在 350℃ 下从研磨材料中回收了约 80-90% 的咖啡因。这些结果显示了新型热解器在从生物质材料中提取有用成分方面的优势。