西北地区农业生物质秸秆热特性分析

Thermal characteristics of agricultural biomass in Northwest China

【目的】分析西北地区农业生物质秸秆的热特性,为合理有效利用西北地区农业生物质能奠定基础。【方法】采集陕西、甘肃、宁夏、青海、西藏和新疆等6省(自治区)97个县(市)252个小麦、玉米、水稻、油菜、棉花等5种秸秆样品,采用瞬态热线法测定秸秆的热传导率、热扩散率和比热容,统计分析不同种类、不同地域秸秆热特性的差异性,采用GIS技术分析西北各省(区)秸秆热传导率的区域分布规律。【结果】西北6省(区)小麦秸秆热传导率、热扩散率和比热容的平均值分别为0.103~0.118 W/(m·K)、0.213~0.223mm2/s、0.473~0.526 MJ/(m3·K);6省区玉米秸秆的3个热特性平均值分别为0.105~0.116 W/(m·K)、0.203~0.232 mm2/s、0.479~0.553MJ/(m3·K);陕西、宁夏和新疆水稻秸秆的3个热特性平均值分别为0.103~0.117 W/(m·K)、0.206~0.214mm2/s、0.483~0.572 MJ/(m3·K);陕西、甘肃、青海和西藏油菜秸秆的3个热特性平均值分别为0.108~0.116W/(m·K)、0.202~0.219mm2/s、0.495~0.575 MJ/(m3·K);陕西、甘肃和新疆棉花秸秆的3个热特性平均值分别为0.129~0.132 W/(m·K)、0.182~0.190 mm2/s、0.677~0.710 MJ/(m3·K)。【结论】棉花秸秆热特性与小麦、玉米、水稻和油菜秸秆之间有显著差异;小麦、玉米、油菜秸秆热特性地域差异性显著;热传导率的地域分布表现为从新疆到陕西由西向东逐渐减小;农作物的种类、气候和环境条件对秸秆热特性有一定的影响。

【Objective】This study analyzed agricultural biomass thermal characteristics to provide basis for reasonably and effectively utilizing agricultural biomass energy in Northwest China.【Method】A total of 252 mature biomass samples of wheat straw,corn straw,rice straw,rapeseed straw and cotton straw were collected from 97 counties in Shaanxi,Gansu,Ningxia,Qinghai,Xizang and Xinjiang.Transient heat wire method was used to measure thermal conductivity,thermal diffusivity and specific heat capacity of the samples.Differences in thermal characteristics of straw classified by different species and provinces were analyzed.GIS technique was used to analyze regional distribution of thermal conductivity of straw from the six provinces in Northwest China.【Result】The thermal conductivity,thermal diffusivity and specific heat capacity of wheat straw in the 6 provinces(regions)were 0.103-0.118 W/(m·K),0.213-0.223 mm 2/s and 0.473-0.526 MJ/(m 3·K),respectively.The three thermal characteristics of corn straw were 0.105-0.116 W/(m·K),0.203-0.232 mm 2/s and 0.479-0.553 MJ/(m 3·K),respectively.The three thermal characteristics of rice straw in Shaanxi,Ningxia and Xinjiang provinces were 0.103-0.117 W/(m·K),0.206-0.214 mm 2/s and 0.483-0.572 MJ/(m 3·K),respectively.The three thermal characteristics of rapeseed straw in Shaanxi,Gansu,Qinghai and Xizang were 0.108-0.116 W/(m·K),0.202-0.219 mm 2/s and 0.495-0.575 MJ/(m 3·K).The three thermal characteristics of cotton straw in Shaanxi,Gansu and Xinjiang were respectively 0.129-0.132 W/(m·K),0.182-0.190 mm 2/s and 0.677-0.710 MJ/(m 3·K),respectively.【Conclusion】Thermal characteristics of cotton straw have significant differences with wheat straw,corn straw,rice straw,and rapeseed straw.Thermal characteristics of wheat straw,corn straw and rapeseed straw are significantly different among different regions.Spatial distribution of thermal conductivity tend to decrease from Xinjiang to Shaanxi.The differences in thermal characteristics are likely caused by type,climate and environment conditions.