生物质气化制氢研究现状

重点讨论生物质催化气化制氢的基本原理和基本过程，阐述生物质催化气化制氢、超临界水中生物质催化气化制氢、等离子体热解气化制氢的研究现状，指出生物质气化制氢的广阔前景。     

等离子体氛围下生物质固定床气化性能的模拟研究

为了提高生物质固定床的气化效率,研究等离子体的加入对气化效率的影响.运用了Aspen Plus化工模拟软件,采用银合欢木材作为生物质原料、O2作为气化剂,对生物质在等离子体固定床中的气化过程进行了模拟.通过将等离子体看作一个额外的热源(改变重整区的温度),探究等离子体氛围下生物质固定床中的热解影响因素和热解产气分布.模...     

高频感应耦合等离子体炬设计分析

近廿多年来对高频感应耦合等离子体炬进行了很多理论研究和实验,也发展了一些不同结构型式的等离子体炬。本文全面地分析等离子体炬设计及重要参数选择的依据和方法,特别对金属水冷等离子体炬进行了详细的分析和讨论。     

玉米芯在超临界水中气化制氢实验研究

以玉米芯为原料,羧甲基纤维素纳(CMC)为添加剂,利用连续管流反应器,在反应压力为22.5MPa~27.5MPa、反应器壁温为550℃~650℃、反应停留时间为0.33min~0.67min、物料浓度为3wt%~6wt%的条件下,对玉米芯超临界水气化制氢进行了实验研究。利用正交实验设计与分析方法,得到实验条件范围内玉米芯超临界水气化制氢的最佳反应参数,同时对气化过程主要操作参数的影响进行了分析。实验表明温度对气化影响最大,高温度有利于产氢,气化制氢的最佳压力为25MPa,反应停留时间越长气化越完全,低浓度生物质比高浓度生物质更容易气化。     

焦油对生物质气化再燃还原NO的影响

采用配制含焦油模型化合物的生物质气的方法,实验研究了焦油的加入对生物质气化再燃还原NO的影响.模拟的生物质气化气由H2、CH4、CO、CO2、N2构成,并选择了苯、甲苯、苯酚和苯乙烯作为焦油模型化合物.实验在电加热的刚玉管流反应器中进行,实验温度在900～1,400,℃之间.研究了反应器入口焦油含量、氧气浓度、NO初始浓度、反应停留时间及反应温度等因素对还原NO的影响,分析了含焦油的生物质气化再燃特性.证实了焦油有助于提高生物质气化气还原NO的效率;含焦油的生物质气化再燃的最佳当量比在1.20～1.65之间,并且随着NO初始浓度的增加及停留时间的延长,NO还原效率逐渐增加;高温下,焦油含量较高时,有炭黑生成.     

生物质半焦气化的反应动力学

利用热重分析仪研究了CO2气氛下的生物质半焦的反应性。研究发现，所研究的4种生物质半焦都表现出了相同的反应性趋势。其反应性随着转化率的增加而增加。这可能是由于生物质焦样中的碱金属含量，尤其是钾的含量较高的原因。对比生物质气化反应动力学参数研究表明，4种焦样的气化行为可以用收缩核模型来描述，并求出了4种生物质焦样的反应动力学参数。在不同的CO2分压下进行了花生壳焦样的反应性实验研究，发现焦样的反应性正比于反应气体浓度，求出了花生壳焦样的反应动力学方程式。     

热等离子体医疗废物处理系统的节能分析

文中通过对热等离子体医疗废物处理系统进行改造,利用蓄热式换热器回收其烟气余热用以预热垃圾、气化剂,从而达到节能减排、降低等离子体炬电耗的目的。综合考虑回转式预热器内的换热方式,建立了一维传热模型,归纳了能量守恒方程式及对流、导热、辐射换热系数。结合实验数据计算得到了预热器内垃圾物料经预热获得的总热量及各部分热量占总传热量的百分比。结果表明,利用烟气余热预热医疗垃圾会减少17%～28. 8%的等离子体炬电耗。     

生物质气化过程中燃料氮迁移影响因素实验研究

针对玉米秸秆和锯末两种生物质,进行了生物质气化过程实验,分析了气化参数对燃料氮迁移过程的影响。结果表明,在测试条件下,生物质气化产物中含氮组分浓度主要取决于气化温度,而当量比的影响相对较弱一些。NH_3和N_2是气化产物中氮的主要表现形式,其随气化温度的变化趋势相反。NH_3与N_2之间的转换反应是决定生物质燃料氮迁移演化过程中的一个主要热化学反应。     

流化床生物质气化发电过程动力学建模与验证

为更好地描述生物质气化过程的反应机理,文章从模型采用的反映速率形式出发,对已建立的动力学模型[1]做了进一步修正,并拟和了以松木屑为生物质原料的气化反应动力学参数,建立了包括质量平衡方程、反应动力学方程以及能量平衡方程在内的整体生物质气化动力学模型。最后以MATLB为平台,通过模型仿真,从反应进程以及最终气体组分两个方面验证了模型的可靠性。为进一步应用该模型评价和优化流化床生物质气化过程气化方案和气化参数打下了基础。     

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。     

活塞环表面等离子喷涂强化及耐磨性能的研究

采用等离子喷涂技术,在活塞环表面喷涂一层Mo+28%NiCrBSi复合材料,并对复合材料涂层的金相组织、硬度、抗咬死和耐磨性进行了实验研究。结果表明采用等离子喷涂工艺制备的Mo+28%NiCrBSi复合材料涂层具有良好抗咬死性及耐磨性,是目前理想的活塞环涂层。     

热裂解型等离子点火技术介绍

等离子点火技术是一种有效节油锅炉点火、稳燃和调试用油的重要手段,对降低发电成本,节约油资源,增强国家能源安全有很大意义.介绍了俄罗斯热裂解型等离子点火技术的技术特点、工作原理、应用状况和其等离子枪的结构优点.这一技术在理论和结构上有独特的优点,值得借鉴.     

Plasma catalytic reforming of methane

Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels. This article describes progress in plasma reforming experiments and calculations of high temperature conversion of methane using heterogeneous processes. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius), and a high degree of dissociation and a substantial degree of ionization. The high temperatures accelerate the reactions involved in the reforming process. Hydrogen-rich gas (40% H₂, 17% CO₂ and 33% N₂, for partial oxidation/water shifting) can be efficiently made in compact plasma reformers. Experiments have been carried out in a small device (2–3 kW) and without the use of efficient heat regeneration. For partial oxidation/water shifting, it was determined that the specific energy consumption in the plasma reforming processes is 16 MJ/kg H₂ with high conversion efficiencies. Larger plasmatrons, better reactor thermal insulation, efficient heat regeneration and improved plasma catalysis could also play a major role in specific energy consumption reduction and increasing the methane conversion. A system has been demonstrated for hydrogen production with low CO content (1.5%) with power densities of 30 kW (H₂ HHV)/l of reactor, or 10 m³/h H₂ per liter of reactor. Power density should further increase with increased power and improved design.     

等离子体火焰介电特性理论分析及电容层析成像测量研究

在对甲烷-空气等离子体火焰电离现象、等离子体火焰极化方式作详细分析的基础上,考虑带电粒子运动与电磁场之间的耦合作用,提出了等离子体火焰介电系数的理论模型。辅以静电探针与热电偶对火焰未知参数的测量结果,获得了相对介电系数的理论值。基于电容层析成像实验结果,对火焰重建图像进行标定,获得了被测区域内火焰相对介电系数的实验值。将相对介电系数的理论值与实验值进行对比分析,分析了相对介电系数理论值的误差来源。同时对利用电容层析成像技术进行火焰温度场的标定进行了初步的研究。     

Plasma assisted dissociation of hydrogen sulfide

Dissociation of hydrogen sulfide has been studied in four different discharges: AC corona, dielectric barrier, streamer, and contracted glow discharge. All experiments were done in a single geometry, close to a plug flow reactor, with the goal of fair comparison. The performance of corona discharge and DBD was studied in the initial gas temperature range of 300–1200 K. A specific energy requirement (SER) was calculated as function of energy input for each type of discharge and compared with earlier experimental results and modeling. The results showed that discharges with high E/n and low specific energy input (corona, DBD, and streamer) perform much worse than those with low E/n (contracted glow discharge) where specific energy input was high and gas temperature was elevated. The SER for non-thermal dissociation was 12–14 eV/molec. However, in the case of the contracted glow discharge, SER decreased to 2.4 eV/molec. This SER is close to the value predicted by thermodynamic equilibrium modeling. Further reduction of SER in a plug flow reactor does not seem possible.     

新型离子渗氮炉

针对国内离子渗氮炉使用中常见的问题，从减少炉壁散热损失、增加底座承重能力、提高电极连接可靠性等方面提出了改进设计方案。新的设计中取消了大部分的炉壁冷却水夹层，增加了真空隔热层，升温时减少热量损失，降温时充入压缩空气强制对流冷却，配合快速冷却装置，增加导热系数，加快工件冷却速度。采用圆弧型封头底座，增大炉体承重能力，并改善气体流动的均匀性。输电阴极采用迷宫式屏蔽结构，作为绝缘体的熔铸云母全部屏蔽在钢制外罩之内，不会因放电而损坏；阴极与底座之间采用可靠的密封方式，长期使用不漏气。实际使用表明，新型离子渗氮炉可大大降低热量损失，增加承重能力，维护保养方便；输电阴极使用3年不用拆卸，工作稳定可靠，劳动生产率比常规的离子渗氮炉提高30％。     

Plasma gasification of the medical waste

In terms of infection control in hospitals, especially the Covid-19 pandemic that we are living in, it has revealed the necessity of proper disposal of medical waste. The increasing amount of medical waste with the pandemic is straining the capacity of incineration facilities or storage areas. Converting this waste to energy with gasification technologies instead of incineration is also important for sustainability. This study investigates the gasification characteristics of the medical waste in a novel updraft plasma gasifier with numerical simulations in the presence of the plasma reactions. Three different medical waste samples, chosen according to the carbon content and five different equivalence ratios (ER) ranging from 0.1 to 0.5 are considered in the simulations to compare the effects of different chemical compositions and waste feeding rates on hydrogen (H₂) content and syngas production. The outlet properties of a 10 kW microwave air plasma generator are used to define the plasma inlet in the numerical model and the air flow rate is held constant for all cases. Results showed that the maximum H₂ production can be obtained with ER = 0.1 for all waste samples.     

等离子体辅助丙酮低温氧化的研究

考虑到小分子含氧组分在等离子体助燃体系中重要的研究意义,本文以丙酮为研究载体,基于先进的分子束质谱诊断平台开展了研究．提供了详细的中间体组分信息,并基于此构建了丙酮等离子体的低温反应网络．结果表明,在等离子体放电激励的作用下,丙酮的燃料氢提取过程被加速,并且还伴随着明显的燃料碎片化过程．研究发现,无势垒反应在等离子体低温氧化的反应机制中十分重要．另外,本文还给出丙酮低温氧化在不同电压激励下的定量结果．     

Plasma assisted combustion: Dynamics and chemistry

Plasma assisted combustion is a promising technology to improve engine performance, increase lean burn flame stability, reduce emissions, and enhance low temperature fuel oxidation and processing. Over the last decade, significant progress has been made towards the applications of plasma in engines and the understanding of the fundamental chemistry and dynamic processes in plasma assisted combustion via the synergetic efforts in advanced diagnostics, combustion chemistry, flame theory, and kinetic modeling. New observations of plasma assisted ignition enhancement, ultra-lean combustion, cool flames, flameless combustion, and controllability of plasma discharge have been reported. Advances are made in the understanding of non-thermal and thermal enhancement effects, kinetic pathways of atomic O production, diagnostics of electronically and vibrationally excited species, plasma assisted combustion kinetics of sub-explosion limit ignition, plasma assisted low temperature combustion, flame regime transition of the classical ignition S-curve, dynamics of the minimum ignition energy, and the transport effect by non-equilibrium plasma discharge. These findings and advances have provided new opportunities in the development of efficient plasma discharges for practical applications and predictive, validated kinetic models and modeling tools for plasma assisted combustion at low temperature and high pressure conditions. This article is to provide a comprehensive overview of the progress and the gap in the knowledge of plasma assisted combustion in applications, chemistry, ignition and flame dynamics, experimental methods, diagnostics, kinetic modeling, and discharge control.     

等离子体技术在多晶硅还原炉的应用

针对内蒙多晶硅项目,在等离子体发生器对还原炉内部进行加热的条件下,对炉内温度场进行了试验测试,同时采用FLUENT软件对其进行了数值模拟。理论和计算的综合结果表明,等离子体加热技术在多晶硅还原炉中有着良好的加热应用效果。与同类型加热设备卤素灯相比,等离子发生器不仅加热效率高且运行成本相对较低,具有良好的应用前景。