不同平茬周期柠条的燃烧特性及热值

柠条是西北地区水土保持,防风固沙造林中的重要灌木树种,可作为生物质燃料使用,但随林龄增加出现生长衰退,效益下降等问题。利用平茬技术可以提高柠条利用率,该文以宁夏盐池平茬1~5 a生柠条为研究对象,对其生长指标、工业分析、硫含量、热值和热重进行了分析。结果表明:1)经平茬后的柠条生长指标每年递增,但3 a以后增幅不大,选定平茬期为3 a的柠条株高、地径和分支数分别比6 a老龄林提高了16.67%、11.54%和160.00%,表明平茬技术有利于柠条生长。2)通过热值分析对1~5 a生柠条进行了比较,发现3~5 a生柠条发热量较好,但三者相差不多;考察了不同月份收割柠条的影响因素,研究表明10-12月柠条各项指标处于最优值。3)比较了柠条和煤的硫含量,分析表明柠条硫含量是烟煤的1/12倍,柠条作为燃料会大大减少硫化物的排放。4)工业分析和热重分析表明,柠条和煤产生的灰分作相比,柠条产生的灰分是烟煤的1/9倍,可减少颗粒物的排放,有利于环境保护。5)采用一级反应动力学模型和积分法对生物质燃烧动力学参数的研究表明,柠条具有较低的活化能,有利于燃烧。综上所述,采用平茬期为3 a且每年10-12月生的柠条最适宜作为热电厂燃料。柠条作为发电燃料具有含硫量低,灰分少,对环境保护和减少可吸入颗粒物具有重要的意义。

Thermal analysis and combustion characteristics in different stumping period of caragana korshinskii

Abstract: Caragana korshinski, an shrub species, is very important to soil and water conservation. Korshinskii not only can be used as wind-break and sand-fixation can also be deemed to be economic crops. However when age increases, some problem exist, such as the decrease of growth and beneath and so on. The stubble technology in Caragana growth, not only to make it more robust growth can also produce a large number of korshinskii. Caragana is a high-value crop economy, is often used as livestock feed, as have better combustion characteristics to be used as fuel. Northwest of Chinese Caragana yield is large, it can replace coal, for power generation. Caragana utilization technology can not only improve its economic value, increase revenue for the local, but also reduce environmental pollution. Ningxia region has a large Caragana, but usually used as domestic fuel, which value low. It's a study of caragana korshinskii in Ningxia province. Through the growth index, industry analysis, sulfur analysis, calorific value, and thermal gravimetric analyzes. The results indicated: 1)Three years later after stumping, plant height, basal diameter and number of branches were higher than CK by 16.67%, 11.54% and 160.00%. This shows take appropriate stumping period can make korshinskii grow more vigorous, and korshinskii production increased more than doubled. 2)By analyzing the calorific value of five students Caragana were compared, Korshinskii heat value increases with it's age, korshinskii and found 3-5 years old Caragana heat better, but it was not much difference; Caragana through different months from October to December harvest harvesting Caragana found most beneficial. 3)From the analysis of the sulfur content, Caragana sulfur content is 1/12 times of bituminous coal. 4) Industry analysis and thermo gravimetric analysis showed that caragana korshinski and coal ash generated as compared, Caragana ash is 1/9 times of bituminous coal, Dust is a major pollutant of the city. Dust is mainly produced by burning coal, including power plants, combustion boilers. PM2.5 and PM10 is due primarily to burn a lot of coal, the coal will not only generate large amount of dust, but also produce many sulfide and nitrogen oxides and other harmful substances. So it should be possible to reduce the use of coal. Korshinskii contain small amounts of sulfur compounds and ash, it is a good substitute for coal, which benefits the environment. 5)Kinetics parameters of activation energy E and frequency factor A were deduced by reaction kinetics equations. It indicated that biomass has lower E value. So it's easy to be ignited. The activation energy korshinskii 3 years old and above growth cycle is relatively low, the escape of volatile combustion stage and the activation energy in the 2.31-2.77 kJ/mol range, fixed carbon combustion stage activation energy of about 35.26-40.45 kJ/mol in the range. In summary, by stumping for a period of three years of caragana are most suitable as a thermal power plant fuel.