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Form transition of sodium during combustion of black liquor coal slurry

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Journal of China University of Mining and Technology 2008年第1期18卷 6-12页

作者： LAN Ze-quan CAO Xin-yu zhou jun-hu LIU Jian-zhong2, CHENG jun CEN Ke-fa North China Institute of Science and Technology Yanjiao Hebei 065201 China State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou Zhejiang 31.0027 China

Several typical ash samples from a 0.25 MW test furnace fired black liquor coal slurry were selected for investigation. The phases and compounds containing sodium in ash samples were acquired from X-ray diffraction analyses. As well, detailed analyses of the amounts of major mineral elements along thickness gradients of representative ash samples were carried out. The elements, including Na, Si, A1, S and C1 were analyzed by the advanced electron probe microanalyzer equipment, which provid evidence and interpretation for the analytical results of XRD. The findings indicate that the occurrence form of sodium has experi- enced important changes during the combustion of black liquor coal slurry, which translated into nepheline, thenardite, sodium sulfate, sodium chloride, sodium silicoaluminate, hanyne and other phases containing sodium, from NaOH, Na2CO3 and Na2S in raw fuel. Of all the sodium compounds, nepheline, thenardite and sodium sulfate are the most important forms of Na in solid com- bustion residues. Such a transformation of Na during the combustion of black liquor coal slurry resulted in a considerable impact on ash deposition and is not only different from the raw coal and papermaldng black liquors, but is also affected by local circum- stances in the combustion furnace. Amounts of Na, S and C1 in ash deposits from low temperature zones were larger than those from high temperature zones. Our findings should provide important theoretical instructions for industrial applications of black liquor coal slurry.

关键词： black liquor coal slurry sodium form transition ash deposition

Accurate location of all surface wave modes for Green's functions of a layered medium by consecutive perturbations

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Science China(Information Sciences) 2010年第11期53卷 2363-2376页

作者： SONG Zhe, zhou HouXing, hu jun, LI WeiDong & HONG Wei State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China State Key Laboratory of Millimeter Waves School of Information Science and Engineering Southeast University Nanjing China

In this paper, an efficient method is proposed to quickly and accurately locate all the surface wave modes of spectral Green’s functions of a layered medium. This method consists of two parts. In the first part, all the surface wave poles without considering the medium loss are located by a modified dichotomy on the real axis in the complex plane. In the second part, consecutive perturbations with respect to the medium loss are performed, which means that the medium loss is increased step by step from zero to the given value, and at each step, the Newton-Raphson algorithm is employed to find all the current poles, with the poles at the previous step as initial values. The residues of the surface wave poles are analytically calculated without any contour integral. The whole procedure is based on the recursively rational forms of spectral Green’s functions. As an application, all the surface wave poles and their residues obtained by the method proposed in this paper are applied in evaluation of the spatial Green’s functions by the discrete complex image method. Some numerical examples are provided to validate the correctness and efficiency of the proposed method.

关键词： Green’s function Sommerfeld integral surface wave pole perturbation discrete complex image method

A New Biflavone from Selaginella pulvinata Maxim

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有机化学 2003年第Z1期23卷 395-396页

作者： XU Kang-Ping XU Zhi DENG Yin-hua LI Fu-Shuang zhou Ying-jun hu Gao-Yun TAN Gui-Shan Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078 Department of Medicinal Chemistry School of Pharmaceutical Sciences Central South University Changsha 410078

　　Selaginella pulvinata Maxim. distributes all over the country of China and is used for the treatment for haemor rhage. [1] We studied on the chemical constituents of S. pulvinata in order to find the active compounds. Dried stems and leaves of S. pulvinata (6.5 kg) were extracted with 70% ethanol twice. The extract was evaporated under vacuum and than suspended in water, extracted with petroleum and EtOAc sequentially. The EtOAc extract was chromatographed on silica gel, eluted with CHCl3-MeOH. As a result, a novel biflavone, named pulvinatabiflavone, was obtained from fractions 75 ～ 78. Its structure was determined on the basis of spectroscopic analysis as 5,5″, 4′″ trihydroxy-7,7″-dimethoxy-[4′-O-6″]-biflavone (compound 1).……

关键词： spectroscopic analysis chemical constituents silica gel in order

Raman Lidar Measurements of Aerosol and Cloud Optical Properties in the Troposphere

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Chinese Journal of Lasers 2002年第1期11卷 74-79页

作者： WU Yonghua hu Shunxing QI Fudi XU Jisheng zhou jun hu huanling (Key Lab of Atmospheric Optics, Anhui Institute of Optics and Fine Mechanics, Hefei 230031, China) Anhui Institute of Optics and Fine Mechanics Key Lab of Atmospheric Optics Hefei 230031

A Raman lidar has been developed with photon counting technique. Aerosol and cloud extinction coefficients are derived by nitrogen (N 2) molecular Raman scatter returns in the troposphere. Both backscatter coefficients and extinction-backscatter-ratios of aerosol and cloud are presented by simultaneously combining N 2 Raman and Mie-Rayleigh returns of aerosol and molecule. Ratios of extinction to backscatter between 20 sr and 70 sr are usually found for aerosol, but less than 15 sr for mid-high altitude cloud in the troposphere.

关键词： Raman lidar aerosol cloud extinction coefficient

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煤粉在高温空气中着火前后孔隙结构的变化

中国电机工程学报 2008年第32期28卷 42-49页

作者：聂欣周志军吕明周俊虎岑可法杭州电子科技大学机械工程学院浙江省杭州市310038 能源清洁利用国家重点实验室(浙江大学) 浙江省杭州市310027

在高温空气点火试验台上,采用不同温度的高温热空气对处于高速湍流流动的烟煤煤粉气流进行快速加热,以模拟煤粉气流在电站锅炉炉膛内受热升温以及初期着火燃烧过程。在煤粉气流发生均相着火前后过程中,对其中不同粒径煤粉的孔隙结构及... 详细信息

在高温空气点火试验台上,采用不同温度的高温热空气对处于高速湍流流动的烟煤煤粉气流进行快速加热,以模拟煤粉气流在电站锅炉炉膛内受热升温以及初期着火燃烧过程。在煤粉气流发生均相着火前后过程中,对其中不同粒径煤粉的孔隙结构及其比表面积随热风温度的升高而产生的变化进行了试验研究。结果表明,煤粉颗粒孔隙主要受热变形和挥发分析出2方面的影响,产生截然相反的2种变化趋势。由于不同粒径煤粉颗粒传热特性的差异,当粒径较大且热风温度较低时,其孔隙结构的变化以热变形的影响为主,孔隙产生闭合;当粒径较小且热风温度较高时,则挥发分析出的影响占优,孔隙出现增长。随着热风温度的升高,小于3nm的孔隙随挥发分析出的加剧而急剧增加。

关键词：煤粉着火孔隙结构比表面积

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煤粉气流在高温空气中着火与熄火的试验研究

中国电机工程学报 2008年第14期28卷 67-72页

作者：聂欣周志军吕明周俊虎岑可法杭州电子科技大学机械工程学院浙江省杭州市310018 能源清洁利用国家重点实验室(浙江大学) 浙江省杭州市310027

提出了一种新型的高温空气煤粉直接点火燃烧器,并建立了相关试验系统平台。选用神华混煤,在成功点燃冷态煤粉气流的基础上,对影响着火与熄火热空气温度的各个因素(煤粉粒径、煤粉浓度、一次风流量、热风流量)进行了试验研究。试验结果表... 详细信息

提出了一种新型的高温空气煤粉直接点火燃烧器,并建立了相关试验系统平台。选用神华混煤,在成功点燃冷态煤粉气流的基础上,对影响着火与熄火热空气温度的各个因素(煤粉粒径、煤粉浓度、一次风流量、热风流量)进行了试验研究。试验结果表明,随着一次风流量的增大或煤粉浓度的降低,着火与熄火热空气温度下降,且一次风流量的影响更为显著;热风流量对其影响呈现两面性。在3种试验煤样中,粒径分布越细的煤样,其着火与熄火热空气温度相差越大。其余各因素对细颗粒煤粉气流的着火热空气度产生的影响比粗颗粒大;而对粗颗粒煤粉气流的熄火热空气温度的影响又大于细颗粒。

关键词：煤粉气流高温空气点火热空气温度着火熄火

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选择非催化还原过程中的N_2O生成与排放

中国电机工程学报 2005年第13期25卷 91-95页

作者：周俊虎杨卫娟周志军岑可法浙江大学能源洁净利用与环境工程教育部重点实验室浙江省杭州市310027

以煤粉燃烧锅炉为代表的高温燃烧一般不是主要的N2O生成源,但在应用选择非催化还原(SNCR)技术控制NO时,会生成一定的N2O.采用化学动力学计算和试验方法研究N2O排放浓度与SNCR技术使用还原剂类型、还原剂用量、反应温度、混合条件和反应... 详细信息

以煤粉燃烧锅炉为代表的高温燃烧一般不是主要的N2O生成源,但在应用选择非催化还原(SNCR)技术控制NO时,会生成一定的N2O.采用化学动力学计算和试验方法研究N2O排放浓度与SNCR技术使用还原剂类型、还原剂用量、反应温度、混合条件和反应时间之间的规律.试验和计算结果表明当反应时间足够时,反应温度越高、还原剂用量越少,N2O排放浓度越低.在SNCR反应过程中,N2O浓度呈先增后减的变化趋势.氨一SNCR试验结果表明N2O排放浓度在0～7μmol/mol之间.尿素一SNCR中约有8.7%的NO转化为N2O,排放为27.8μmol/mol,可能引起N2O排放问题.

关键词：热能动力工程选择非催化还原 N2O 氮氧化物氨尿素

基于锅炉低NO_x再燃技术中再燃燃料选择的讨论

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热能动力工程 2005年第3期20卷 226-229页

作者：董若凌周俊虎岑可法浙江大学热能工程研究所能源洁净利用与环境工程教育部重点试验室浙江杭州310027

再燃是一种清洁燃烧技术,可以实现锅炉低NOx排放。着重阐述了再燃技术基础及其反应机理,以及天然气、煤粉和煤浆等不同再燃燃料对锅炉NOx排放的控制效果和各自特点。不同燃料的再燃特性和运行成本有一定差异,根据燃料特点和使用经济性... 详细信息

再燃是一种清洁燃烧技术,可以实现锅炉低NOx排放。着重阐述了再燃技术基础及其反应机理,以及天然气、煤粉和煤浆等不同再燃燃料对锅炉NOx排放的控制效果和各自特点。不同燃料的再燃特性和运行成本有一定差异,根据燃料特点和使用经济性来选择再燃燃料,可以满足现有锅炉污染控制的经济要求和环境要求。

关键词：再燃脱硝天然气煤粉煤浆

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煤液化残渣与褐煤混合燃烧硫污染物排放规律

浙江大学学报（工学版） 2006年第1期40卷 131-134,138页

作者：周俊虎方磊程军刘建忠周志军岑可法浙江大学能源清洁利用国家重点实验室浙江杭州310027

用ZCS-1型智能化定硫仪研究了神华煤液化残渣与褐煤混煤燃烧时硫污染物的动态排放特性,研究发现单煤及混煤燃烧时硫析出速率曲线呈双峰结构.由煤液化残渣、古山煤和风水沟煤配成的三元混煤的硫析出速率双峰曲线比煤液化残渣和风水沟煤... 详细信息

用ZCS-1型智能化定硫仪研究了神华煤液化残渣与褐煤混煤燃烧时硫污染物的动态排放特性,研究发现单煤及混煤燃烧时硫析出速率曲线呈双峰结构.由煤液化残渣、古山煤和风水沟煤配成的三元混煤的硫析出速率双峰曲线比煤液化残渣和风水沟煤配成的二元煤平缓.当高硫的煤液化残渣掺混比减少时,二元混煤或三元混煤的最大硫析出量都逐渐减少,硫析出速率逐渐降低,且其峰值时间均有所延迟.

关键词：煤液化残渣褐煤混煤硫动态排放