玉米秆超临界甲醇解聚产物分析

以甲醇为溶剂对玉米秆进行超临界解聚,采用FTIR和GC/MS分析解聚产物.结果表明,超临界甲醇解聚产物(SCMD)中成分十分复杂,GC/MS分析鉴定出103种有机化合物,其中83种为含氧有机化合物,有酯、酚、醚、醇、酮和醛等,还检测出少量正构烷烃(C15-C17和C19-C27)、烯烃、芳烃、苯硫酚和含氮有机化合物,反映了SCMD的高含氧量和低含氮硫量的特性.SCMD中31.387%的苯酚类物质和5.022%的芳烃类物质可能来源于木质素在超临界甲醇中的解聚作用,而34.629%的甲酯类化合物可能是解聚产生的脂肪酸和苯内酸等与甲醇酯化的结果.由此町以推断出甲醇在玉米秆的超临界解聚过程参与了玉米秆的解聚反应.     

高效超临界锅炉技术综述

本文介绍了高效超临界技术的发展现状、技术特点和几台典型的高效超临界电站锅炉。     

超临界及高效超临界锅炉水冷壁结构设计比较

通过比较600MW及其以上超临界和高效超临界锅炉的水冷壁结构,阐述了螺旋上升管圈水冷壁和垂直水冷壁结构的优点和缺点,为锅炉水冷壁结构设计提供参考。     

高效低污染超临界发电技术

本文介绍了超临界压力火电机组的一些概念以及形成超临界压力火电技术的理论基础,对超临界与亚临界火电机组在许多方面做了相应的比较;同时对超临界压力火电机组的技术特点进行了分析与总结。     

高效超临界汽轮机的研究与开发

概述了目前世界上高效超临界汽轮机的发展状况，主蒸汽、再热蒸汽参数对高效超临界汽轮机经济性的影响，并着重探讨了我国发展高效超临界汽轮机应选取的参数、发展步骤及汽轮机应重点开展的研究课题。表2参7     

不同参数高效超超临界机组经济性分析及建议

本文根据目前大量已投运二次再热机组运行经验,结合某660MW项目高效一次再热和二次再热不同的高效超超临界参数,结合对应的汽机热平衡图参数,通过对THA、80%THA、60%THA三个运行负荷进行了相关的机组经济性参数的计算和对比,通过分析提出了在选择一次再热或二次再热参数上的一些建议和结论。     

准东煤与玉米秆共热解特性及气体产物释放规律

利用热重-质谱联用(TG-MS)和原位漫反射傅里叶变换红外光谱(in situ DRIFT)等实验手段对准东煤与玉米秆的混合样品进行共热解实验,研究了共热解中主要小分子气体(H2、CH4、CO和CO2)的释放规律,探讨了样品中官能团对小分子气体释放的影响.结果 表明:准东煤与玉米秆共热解组分相互作用,当玉米秆与准东煤的...     

聚合度对生物质多糖醇解影响研究

通过生物质醇解制备液体燃料与化学品获得广泛关注,但该方法存在产物复杂、选择性低、反应机理不清等问题.本文主要研究具有不同聚合度的糖类在乙醇溶剂中的反应特性.结果表明:随着温度的升高,葡萄糖、蔗糖、纤维二糖的转化率提高,转化率大小均为葡萄糖>蔗糖>纤维二糖>纤维素;在160～200℃,葡萄糖主要生成5-羟甲基糠醛,纤维二...     

玉米秆与玉米芯热重分析

用热重分析仪对玉米秆和玉米芯的热解和燃烧动力学特性进行了研究,通过热解试验发现玉米秆和玉米芯挥发分的析出基本在一个阶段内完成,而燃烧试验研究表明燃烧过程主要由挥发分的燃烧和焦碳及残余挥发分的燃烧这两个阶段组成。上述结果为进一步有效利用玉米秸秆提供了一定的理论基础。     

秸秆燃气合成甲醇的优化试验研究

以秸秆合成气为原料,在直流流动等温积分反应器中,使用国产C301铜基催化剂,在5 MPa压力下,进行催化合成甲醇的反应温度、秸秆合成气配比、合成气进口流量的优化试验研究.试验获得了玉米秸秆合成气合成甲醇的最佳反应条件,为生物质（秸秆）气制甲醇中试研究提供科学和实用的参考依据.     

超(超)临界锅炉启动系统安全性影响的定量分析

对各类型启动系统的安全性影响进行了定性对比分析,重点采集并定量计算分析了超(超)临界锅炉启动阶段的实际运行数据。定量分析结果表明采用带BCP的启动系统在安全方面有明显优势;而采用大气扩容器启动系统时,锅炉转干态前后水冷壁出口温度变化速率较大,且系统无法满足锅炉热态、极热态启动的需要。     

生物质超临界水催化气化制氢实验系统

生物质超临界水催化气化制氢是一项很有价值的离新技术,它有利于开发广泛的生物质资源,为大规模的制氢提供一条高效、清洁的途径。针对生物质超临界水气化制氢,国内外结合工作具体要求和条件,设计出了一系列生物质超临界水催化气化制氢的实验系统。主要对国内外几种较好的生物质超临界水催化气化制氢实验进行了综合评述,分析了各类实验系统存在的问题及待改进之处。     

超临界水中生物质气化制氢的反应路径

超临界水中生物质气化制氢技术因其具有良好的环保性、产氢高等特点已成为氢能领域的研究热点之一。文中对超临界水中生物质气化制氢反应路径的研究结果进行了总结，归纳了生物质及其模型化合物葡萄糖在亚临界和超临界水中分解气化的可能的反应路径以及反应过程中产生的一系列中间产物，讨论了影响反应的主要因素。     

Experimental research on catalysts and their catalytic mechanism for hydrogen production by gasification of peanut shell in supercritical water

Peanut shell, mixed with sodium carboxymethyl-cellulose, was gasified at a temperature of 450°C and a pressure range from 24 to 27 MPa with the presence of different catalysts, including K₂CO₃, ZnCl₂ and Raney-Ni. The experimental results show that different catalysts have greatly different effects on the reaction. Gasification efficiency (GE), hydrogen gasification efficiency (GHE), carbon gasification efficiency (GCE), yield of hydrogen production and potential yield of hydrogen production are applied to describe the catalytic efficiency. From the result of gaseous components, ZnCl₂ has the highest hydrogen selectivity, K₂CO₃ is lower, and Raney-Ni is the lowest, but Raney-Ni is the most favorable to gasify biomass among the three catalysts, and its G _E, G _HE, G _CE reach 126.84%, 185.71%, 94.24%, respectively. As expected, hydrogen selectivity increased and CH₄ reduced rapidly when the mixture of ZnCl₂ and Raney-Ni is used under the same condition. The optimization mixture appeared when 0.2 g of ZnCl₂ was added to 1 g of Raney-Ni, 43.56 g·kg⁻¹ of hydrogen production was obtained. In addition, the catalytic mechanisms of different catalysts were analyzed, and the possible reaction pathway was brought forward, which helped to explain the experiment phenomena and results correctly. __________ Translated from Journal of Xi’an Jiaotong University, 2006, 40(9): 1 263–1 267 [译自: 西安交通大学学报]     

秸秆类生物质催化合成甲醇的实验研究

为了将农业废弃物转变为燃料甲醇,对玉米秸秆燃气进行合成气优化实验,在5MPa压力下,采用等温积分反应器和国产C301铜基催化剂,对合成气进行催化合成甲醇的实验研究。     

Catalytic effects of borax and iron(III) chloride on supercritical liquefaction of Anchusa azurea with methanol and isopropanol

Anchusa azurea is a lignocellulosic gramineous plant, and it has been selected as a renewable feedstock to be used in a liquefaction process to obtain biofuel. Milled Anchusa azurea stalks were converted to liquid products in methanol and isopropanol with (borax or iron(III) chloride) and without catalyst in an autoclave at temperatures of 260, 280, and 300°C. The liquefaction parameter effects such as catalyst, solvents, and temperature were investigated. The highest percentages of liquid yields from methanol and isopropanol conversions were 64.70% (with borax) and 29.20% (with borax) at 300°C in the catalytic runs, respectively. The highest conversion (73.80%) was obtained in methanol with borax catalyst at the same temperature. The obtained liquid products at 300°C were analyzed and characterized by elemental, Fourier transform infrared spectroscopy and gas chromatography–mass spectrometry (GC-MS). Seventy-three different compounds have been identified by GC-MS in the liquid products obtained in methanol at 300°C.     

Structural analysis of bio-oils from sub-and supercritical water liquefaction of woody biomass

Woody biomass was liquefied by water in an autoclave in the reaction temperature range of 280–420 °C with sodium carbonate as the catalyst. The experimental results show that the yield of the main liquefaction product (heavy oil) was significantly influenced by the process conditions. The maximum yield of heavy oil was obtained at reaction temperature 380 °C. The heavy oils obtained at different reaction temperature were analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS). The analytical results show the heavy oil is complex compound that contain hydrocarbon, aldehyde, ketone, hydroxybenzene and ester.     

A system performance and economics analysis of IGCC with supercritical steam bottom cycle supplied with varying blends of coal and biomass feedstock

In recent years, Integrated Gasification Combined Cycle Technology (IGCC) has been gaining popularity for use in clean coal power operations with carbon capture and sequestration. Great efforts have been continuously spent on investigating ways to improve the efficiency and further reduce the greenhouse gas emissions of such plants. This study focuses on investigating two approaches to achieve these goals. First, replace the traditional subcritical Rankine cycle portion of the overall plant with a supercritical steam cycle. Second, add biomass as co‐feedstock to reduce carbon footprint as well as SO_x and NO_x emissions. In fact, plants that use biomass alone can be carbon neutral and even become carbon negative if CO₂ is captured. Due to a limited supply of feedstock, biomass plants are usually small, which results in higher capital and production costs. In addition, biomass can only be obtained at specific times in the year, resulting in fairly low capacity factors. Considering these challenges, it is more economically attractive and less technically challenging to co‐gasify biomass wastes with coal. The results show that for supercritical IGCC, the net efficiency increases with increased biomass in all cases. For both subcritical and supercritical cases, the efficiency increases from 0% to 10% (wt.) biomass and decreases thereafter. However, the efficiency of the blended cases always remains higher than that of the pure‐coal baseline cases. The emissions (NO_x, SO_x, and effective CO₂) and the capital costs decrease as biomass ratio (BMR) increases, but the cost of electricity (CoE) increases with BMR due to the high cost of the biomass used. Finally, implementing a supercritical steam cycle is shown to increase the net plant output power by 13% and the thermal efficiency by about 1.6 percentage points (or 4.56%) with a 6.7% reduction in capital cost, and a 3.5% decrease in CoE. Copyright © 2013 John Wiley & Sons, Ltd.