pH值对微晶纤维素水热炭化影响研究  

INFLUENCES OF FEEDWATER PH VALUE ON HYDROTHERMAL CARBONIZATION OF MICROCRYSTALLINE CELLULOSE

作　　者：施苏薇 马培勇[1,2] 邢献军 范方宇[2] 张贤文 Shi Suwei;Ma Peiyong;Xing Xianjun;Fan Fangyu;Zhang Xianwen(School of Mechanical and Automobile Engineering,Hefei University of Technology,Hefei 230009,China;Institute of Advanced Energy Technology and Equipment,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学机械及汽车工程学院,合肥230009 [2]合肥工业大学先进能源技术与装备研究院,合肥230009

出　　处：《太阳能学报》2021年第8期449-453,共5页Acta Energiae Solaris Sinica

摘　　要：为研究溶液pH值对微晶纤维素(MC)水热炭化进程、水热炭物理化学特性(产率、固碳率、热值、亲水性、芳香性)及表观形貌的影响规律,MC为原料,以反应溶液pH值分别为3.0、4.0、5.0、6.0、7.0、8.0、9.0、10.0、11.0,在220℃,4 h条件下进行水热炭化实验。通过元素分析pH值对水热炭理化特性的影响,并结合范式图综合分析pH值对MC水热炭化反应进程的影响,利用扫描电子显微镜(SEM)观察水热炭表观形貌。结果表明:水热炭产率和固碳率随酸性的增强而减弱,pH值为3.0时,产率及固碳率最小,分别为35.5%、41.82%,热值达到最大,为19.11 MJ/kg,HC3(hydro-char from pH of 3.0)芳香性最好,HC11(hydro-char from pH of 11.0)亲水性最强,碱性和中性水热炭芳香性、亲水性相似,不同pH值条件下的炭化进程均以脱水反应为主;SEM显示酸性水热炭微球粒径随酸性的增强而减小,纤维素在碱性条件下炭微球粒径均匀度较好。In this study,the influence of feedwater pH value(3-11) on hydrothermal carbonization(HTC)of microcrystalline cellulose(MC)at 220 ℃,4 h is studied. Sodium hydroxide, sodium bicarbonate and citric acid are used to prepare solutions of different pH values,respectively. Elemental and scanning electron microscopy(SEM)analyses are used to investigate the influences of the pH values of the solutions from 3 to 11 on the physical,chemical,thermal and structural characteristics of hydro-chars. The van Krevelen diagram is also used to analyze the influences of the pH values of the solutions on the hydrothermal carbonization process. Results show that the mass yield and carbon fixed rate(FC)decrease with increased acidity. Hydro-char yield and FC are only 35.5% and 41.82%under the pH value of 3,and the hydro-char possesses the best aromaticity. Whereas at pH value of 11,the hydro-char yield and FC reach as high as 46.5% and 48.91%,respectively and the hydro-char has the best hydrophilic. Dehydration is the main reaction during the HTC process. SEM images show that the microsphere size of HCA(hydro-chars from acidic condition)decreases with increased acidity while HCB(hydro-chars from basic condition)have uniform microsphere size and good sphericity.

关 键 词：微晶纤维素 PH值 水热炭化 范式图 扫描电子显微镜 

分 类 号：TK6[动力工程及工程热物理—生物能]