摘要
生物质燃烧对全球大气碳排放和气候变化产生重要的影响。近年来,利用生物质制备生物炭实现碳封存备受重视。该文根据2001-2010年中国粮食产量,估算了主要粮食作物秸秆产量,结合秸秆露天焚烧比例及CO和CO2排放因子,得出CO和CO2的排放量及碳排放总量。同时,根据实验室条件下秸秆转化为生物炭的产率及碳含量,估算了中国粮食作物秸秆转化生物炭后固定碳的量。结果发现,中国粮食作物秸秆因焚烧年排放CO、CO2和总碳量分别为1.15×107、1.57×108和4.77×107t。中国粮食作物秸秆全部转化为生物炭后年平均可固碳0.96×108t,如果把每年焚烧秸秆的量全部转化为生物炭可减少近一半因焚烧秸秆排放碳的量,可见,生物炭固碳技术是一种非常有前景的碳汇技术。
The common management of straw is burning in the field, which is considered as a convenient and economical method for farmers to deal with them in China. However, the burning of straw enhances the release of greenhouse gases including CO2. Turning crop residues into biochar under low temperature （usually〈700℃） and limited oxygen conditions has been recently proven as a promising approach for the long term carbon sequestration. However, up to now, the quantity of carbon emission from crop straw burning and the potential of carbon sequestration by turning straw into biochar in China are still unavailable. Hence, in this paper, the quantity was estimated. Based on the data of crop yield from 2001 to 2010 in China, the major straw （rice, wheat, corn and soybean） output was calculated according to the ratio of grain to straw. The proportion and amount of burned straw were quantitatively analyzed. The total amounts of CO and CO2 emission were estimated according to the emission factors derived from references, and the total carbon emission was calculated based on the CO and CO2 emission without thinking of the other forms of C emission. Moreover, biochars were derived from major crop straw under lab conditions （a typical slow pyrolysis process, heated in a muffle furnace at a speed of approximately 20℃ min-1 under limited oxygen and held at 500℃ for 4 h） and the carbon sequestration amount of biochars were estimated according to the carbon contents and yields of biochars. The results showed that annually production of crop straw in China was about 5.1 ×10^8 t, and about 21.6% of them were burned, which led to high CO, CO2 and carbon emission, which were about 1.15×10^7. 1.57×10^8 and 4.77×10^7 t, respectively. Meanwhile, the average carbon contents and yields of biochars were 63.2% and 30%, respectively. Although the stability of biochar and the effect of pyrolysis temperature on the carbon sequestration were not studied in this study, the annually carbon sequestration amount by turning straw into biochars was 0.96×10^8 t and about half of carbon emission was decreased annually if the amount of burned straw was turned into biochar, which indicated that turning straw into biochar was a promising approach for straw management.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2013年第14期1-7,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金(21107070)
安徽省高等学校省级优秀青年人才基金项目(2012SQRL149)
安徽省长三角联合攻关项目(1101c0603046)
安徽省高校重大科研项目(KJ2012ZD04)
安徽科技学院自然科学研究项目(ZRC2013373)
关键词
秸秆
排放控制
碳
秸秆焚烧
碳固定
生物炭
straw, emission control, carbon, straw buming, carbon sequestration, biocha
