中国棉花副产品作为生物质能源利用的潜力评估

中国每年产生丰富的棉花副产品资源,包括棉秆和棉籽。棉秆和棉籽壳纤维素和木质素含量高,棉籽仁含油量高,是适宜的生物质能源原料。从1980年到2014年,棉花主产区向西北内陆的新疆扩展,而在黄河流域和长江流域的种植面积缩小,主要原因是植棉比较效益大幅下降。利用棉花副产品生产生物质能源,是既缓解中国能源压力又提高植棉效益的1个新途径。利用1980―2014年中国各省棉花种植数据,分析30多年来棉花种植的区域变化,估算棉花副产品的产量和作为生物质能源的发展潜力。2014年棉花副产品的理论产量为3244万t,其中棉秆2236万t,棉籽1008万t。利用棉秆和棉籽壳可以生产1084万t生物炭或1355万t生物油,棉籽仁经生物质能源转化后可生产152万t生物柴油。利用棉花副产品生产生物质能源产品(生物油和生物柴油),其能源潜力可达1000万t标准煤。在利用30%和50%的情况下,能源潜力分别达到300万t和500万t标准煤。棉花副产品的能源化利用及其产业化发展不仅能够一定程度上缓解中国能源供应压力,还能促进棉花产业的可持续发展和棉民增收。

Assessment of the Biomass Energy Use Potential of Cotton Byproducts in China

China produces an abundance of cotton byproducts each year, such as cotton straw and cotton seed. Cotton byproducts make useful biomass energy resources as there is high cellulose and lignin content in cotton straw and cotton seed shells, and high oil content in cotton seed kernels. From 1980 to 2014, the main cotton-producing regions in China expanded to Xinjiang in the northwest region, while the cotton planting area in the Yellow River and Yangtze River regions decreased. Cotton byproducts for bioenergy production could provide a new way to relieve energy pressure in China, and enhance the benefits associated with cotton production. Using cotton production data from 1980 to 2013 covering all cotton-producing provinces in China, we analyzed regional distributions and changes in the main cotton-producing regions over the past three decades to determine production and energy potentials of cotton byproducts. In China, the theoretical production of cotton byproducts in 2014 was estimated at 32.44 million tons (Mt); comprised of 22.36 Mt cotton straw and 10.08 Mt cotton seed. Together, cotton straw and cotton seed shells could produce 10.84 Mt biochar or 13.55 Mt bio-oil, and cotton seed kernel could produce 1.52 Mt bio-diesel. The total energy potential of cotton byproducts in China in 2014 reached 10.00 Mt standard coal equivalence. If 30% or 50% of cotton byproducts can be converted into biomass energy, the energy potential would be 3.00 Mt or 5.00 Mt standard coal equivalence, respectively. The cotton byproducts for bioenergy and its industrial development will not only be helpful to relieve pressure on the energy supply, but also contribute to sustainable development of the cotton industry and increase the income of cotton farmers.