柴油机碳烟低温燃烧(氧化)过程及其动力学参数的研究

利用固定床反应器,对标致 雪铁龙汽车公司提供的两种碳烟,在水蒸汽存在的情况下进行了低 中温燃烧(氧化)反应。进而经过数值计算和数学模拟,得出了燃烧反应的动力学参数。对于形成CO的反应,指前因子k0介于(1 55×104～3 40×107)s-1之间,活化能E介于(127 86～188 23)kJ·mol-1之间;对于形成CO2的反应,k0介于(1 68×103～4 18×105)s-1之间,活化能E介于(89 38～181 46)kJ·mol-1之间。这一结果可能为碳烟治理提供可资借鉴的基础数据。     

生物质燃烧动力学特性实验研究

采用非等温热重分析法对农作物秸秆燃烧动力学特性进行了研究。提出了秸秆挥发分析出过程的特性参数，建立了反应动力学方程；测算了反映燃烧性能的燃烧特性指数和反映生物质秸秆燃烧放热特性的差热峰面积指标。结果表明：玉米秸秆和小麦秸秆的挥发分初析温度随升温速度的增加而降低，稻秆的挥发分初析温度随升温速度的增加而增加；3种样品的活化能随升温速度的增加而降低；差热峰面积、燃烧特性指数随升温速度的增加而增大。     

生物质焦油燃烧动力学特性研究

对生物质焦油进行了馏程试验．采用非等温热重分析法研究了生物质焦油及其馏分的燃烧动力学过程，提出其反应动力学方程。根据试验结果探讨了焦油资源化利用的途径，为焦油的综合利用提供了重要的科学参考依据。     

稻秆燃烧动力学特性研究

通过热重分析方法研究了稻秆的燃烧过程及其动力学特性.非等温热重法的升温速率分别为20 ℃/min、30 ℃/min、40 ℃/min,加热终温800 ℃;采用空气为载气.得到稻秆燃烧的TG、DTG曲线,研究了加热速率、温度对燃烧过程的影响,建立了稻秆燃烧的反应动力学方程,由Freeman-Carroll法得到该类稻秆燃烧动力学参数,并提出了相应的燃烧机理.为燃烧稻秆锅炉的设计开发提供了理论支持.     

酥油等温燃烧化学动力学研究

使用锥形量热仪研究100mm×100 mm×10mm的固体酥油在不同温度下的燃烧反应,采用化学动力学法拟合了酥油燃烧过程中质量损失率与时间的单方程模型．结果显示,在酥油燃烧过程中,质量损失速率受产物的解吸附和扩散过程控制．酥油在947-1 165 K燃烧时,合适的反应动力学方程为a1/2=Ae-E、RTt,其中指前因子A等于0．021 3 s-1,平均表观活化能E为17．69 kJ／mol,A和E与温度的变化基本无关,计算结果与实验数据吻合较好．     

稻壳燃烧实验研究及综合动力学模型

本文采用热重法对稻壳进行了燃烧实验研究，探讨了升温速率、环境氧浓度和稻壳形态对稻壳燃烧过程的影响。本文同时提出了包括水份析出、挥发份析出和炭燃烧的综合动力学模型，通过计算机优化迭代得到了稻壳燃烧动力学参数，这对于稻壳燃烧（汽化）装置的设计以及开展燃烧过程数值计算具有实用意义。     

稻秆燃烧过程动力学特性试验

采用非等温热重分析法对稻秆燃烧动力学特性进行研究，提出了稻秆的挥发分析出过程的特性参数，建立了反应动力学方程，并测算了反映燃烧性能的燃烧特性指数和反映稻秆燃烧放热特性的差热峰面积指标。结果表明：稻秆的挥发分初析温度随升温速度、样品粒度和样品质量的增加而增加；稻秆的活化能随升温速度的增大、样品粒度的减小和样品质量的减少而降低。差热峰面积随升温速率的提高和样品粒度的减少而增加；燃烧特性指数随升温速度的增大、样品质量的增加和样品粒度的减小而增大。     

医疗废物燃烧过程动力学研究

为开发适合我国城市医疗垃圾集中处置的医疗废物焚烧技术,对昆明市医疗废物进行了特性分析,并模化医疗废物,对纸屑、塑料、棉纱、橡胶、组织(肌肉)等试样进行了实验研究．在热重分析仪上通以流量为50 mL/ min的空气,以10℃/min的升温速率从室温连续升至1000℃,记录了试样的TG曲线、DTG曲线与DTA曲线．分析研究表明,模化医疗废物的燃烧过程可以分为4个阶段,即脱水干燥、挥发分析出和燃烧、过渡段和焦炭表面燃烧并存的过渡阶段、焦炭的表面燃烧．医疗废物具有着火温度低、燃尽率高等特点．通过对热重(TG)、差示扫描量热(DSC)曲线的深入分析,对模化医疗废物有关的燃烧动力学参数进行了研究。     

旋涡流化床旋风燃烧的动力学研究

以旋涡流化床悬浮空浮空间喷入二次风形成一强放流场和气固悬浮流动为物理模型,试验研究了床面夹带到悬浮空间颗粒群的运动行为及气固两相浓度场的匹配,指出在气相强旋湍流的作用下,在近壁区形成一稳定的高浓度的颗粒悬浮层,颗粒在炉内的平均停留时间延长,气固滑移速度增大,两相混合强并充分接触,良好的空气动力结构对提高炭粒在悬浮空间的燃尽度,降低场析可燃物质损失十分有利,本文研究结果,对降低常规鼓泡床及抛煤机链条炉内的飞灰可燃物损失,提高悬浮空间的气流横向混合速率有重要参考价值。     

Experimental study on oxy-fuel combustion of heavy oil

Oxy-fuel combustion of heavy oil can be applied to oil field steam injection boilers, allowing the utilization of both heavy oil and CO₂ resources. The present study investigated the oxy-fuel combustion characteristics of heavy oil under different conditions, including the flame, temperature, and pollutant emission characteristics. The results showed that heavy oil combustion was stable at O₂ concentrations of 29%, as the O₂ concentration was increased, the flame began to brighten gradually, becoming shorter and thicker, while the temperature gradient became higher and the high temperature zone moved closer to the burner exit. The overall temperature and the combustion rates in O₂/CO₂ atmospheres were below those seen in O₂/N₂ atmospheres. The volume of NO emitted in the flue gas was almost unaffected by the change in O₂ concentrations in atmospheres containing high concentrations of CO₂, but it increased rapidly with increasing O₂ concentration in O₂/N₂ atmospheres.     

Enhanced in situ combustion of heavy crude oil by nickel oxide nanoparticles

Nickel oxide nanoparticles were synthesized by microemulsion method and characterized by powder X‐ray diffraction, dynamic light scattering, and scanning electron microscopy. Thermal analyses were performed to identify the influence of nickel oxide nanoparticles on the in situ combustion of Liaohe heavy oil. Low‐temperature oxidation and coking process were investigated by analysing the effluent gases and the fractions of saturates, aromatics, resins, and asphaltenes. Combustion tube tests were also conducted to evaluate the catalytic performance of nickel oxide nanoparticles. Compared with the runs without catalysts, the effective activation energies were reduced by 4.22%, 20.57%, and 35.75% in terms of low‐temperature oxidation, pyrolysis, and high‐temperature oxidation, respectively. The reduction in O₂ fraction and the increase in CO₂ and O₂ uptake were also confirmed. The overall trend presented the increase of saturates and aromatics fraction and the decline of resins and asphaltenes fraction while temperature was increased during low‐temperature oxidation. Adding nickel oxide nanoparticles led to the reduction in the fuel deposit during pyrolysis. Compared with the base combustion tube runs, combustion time in catalytic experiment was shortened by 12.1%, combustion front movement was accelerated by 9.1%, oil recovery was enhanced by 4.0%, and oil viscosity was reduced by 61.2%.     

Experimental study on the flame propagation characteristics of heavy oil oxy-fuel combustion

This paper studied the flame propagation characteristics of heavy oil oxy-fuel combustion in ignition and stable combustion. The results showed that the ignition process could be divided into three stages: the pro-ignition, mid-ignition and end-ignition. The pro-ignition, the fire core generated and evolved into spherical; the mid-ignition, the spherical fire core gradually turn into tapered structure; the end-ignition, the flame tapered structure disappeared and turn into a relative stable columnar structure. By calculating the flame propagation velocities, we found that in the same combustion atmosphere, the flame propagation velocity in 29% O2 was higher than that in 21% O2; in the same O₂ concentration, the flame propagation velocity in O₂/N₂ atmosphere was higher than that in O₂/CO₂. During the stable combustion, we observed the local flame structure extinguished, distorted and grew.     

秸秆类生物质燃烧动力学特性实验研究

生物质能的利用越来越受到重视。直接燃烧技术由于其操作简单、取材方便、成本适宜等特点是一种符合我国国情的生物质能利用方式。采用热重分析的研究方法,对水稻秸秆、玉米秸秆和玉米芯三种秸秆类生物质的燃烧动力学特性进行了实验,研究了不同升温速率、氧浓度对不同种类的秸秆生物质燃料燃烧动力学特性的影响,并对着火温度、燃烧稳定性、挥发分析出特性、燃烧特性指数等相关特性参数进行定量分析,为设计秸秆工业锅炉燃烧设备,合理选择生物质种类、优化燃烧、提高锅炉效率提供了理论支撑。     

Effect of low-temperature oxidation on the pyrolysis and combustion of whole oil

Low-temperature oxidation (LTO) of the Fosterton crude oil mixed with its reservoir sand has been investigated in a tubular reactor. Reservoir sand saturated with 15 wt% of crude oil (20.5° API gravity) was subjected to air injection at low-temperature (220 °C) for a period of time (17 h and 30 min), resulting in the formation of an oxygenated hydrocarbon fuel. The vent gases were analyzed for the content of CO, CO₂, and oxygen and the residue was analyzed to determine the elemental composition and calorific value. The presence of LTO region was verified from the values of apparent H/C ratio. In addition, thermal behavior and combustion kinetics of the residue was investigated using thermogravimetric analysis (TGA). TG involves both non-isothermal and isothermal analysis and kinetic data was derived from isothermal studies. The general model for nth order reaction was used to obtain the kinetic parameters of the coke oxidation reaction. The activation energy, frequency factor and order of the reactions were determined using the model.     

Oxy-fuel combustion of heavy oil based on OH - PLIF technique

Oxy-fuel combustion of heavy oil can be applied to oil field steam injection boilers, allowing the utilization of both heavy oil and CO₂ resources. This paper studied the local distribution characteristics of OH on oxy-fuel combustion of heavy oil during the ignition and stable combustion processes. During the ignition process, we observed the generation and evolution of fire kernel, and got the flame propagation velocity. During the stable combustion process, the results showed that the OH distribution and its relative signal intensity were influenced by the oxygen concentration, excess air coefficient, gas flow, reaction atmosphere, oil mist scattering, incident laser energy and laser sheet position. In the same reaction atmosphere, the ranges of OH dense distribution and the high temperature area increased as O₂ concentration increased. In the same O₂ concentration, both the ranges of OH dense distribution and the high temperature area in O₂/N₂ were larger than that in O₂/CO₂. In 29% O₂/71% CO₂, the flame shape was similar to combust in air, while the OH relative signal intensity and its volatility were much larger than that in air. In the same combustion condition, the location of high concentration of OH relative concentration field lagged behind the high temperature area. The results further reveal the differences between the conventional and oxy-fuel combustion.     

The kinetics and thermochemistry of chemical oxidation with application to combustion and flames

The chemistry, thermochemistry and kinetics of hydrocarbon oxidation is described with emphasis on the cool flame regime from 200–400°C over which the initial chemistry changes from hydroperoxide production to H₂O₂ production. The development of cool flames in RH + O₂ mixtures is shown to be characterized by a short initial period of very slow radical production yielding RO₂H as product which then autocatalytically accelerates its own production with propagation by RO^.₂(HO₂)+RH → RO₂H (HO₂H)R′. As (RO₂H)/(RH) exced 10^?3, propagation is taken over by OH and (RO₂H) reaches a stationary concentration. In these final approaches to stationary state, aldehydes which are produced along with RO₂H act as important H donors in competition with RH and produce peroxy acids which are faster branching agents than RO₂H. The negative temperature coefficient in the cool flame region is described kinetically and arises from a turnover in mechanism producing H₂O₂ instead of RO₂H. Hot ignition is briefly discussed as are liquid phase oxidation and modelling. Rate constants and thermochemical data are provided for the key steps and species.     

几种生物质的TG-DTG分析及其燃烧动力学特性研究

采用热重分析技术对木屑、麦秆、玉米秆和玉米芯4种生物质的燃烧特性进行了研究,考察了其着火、燃尽特性和综合燃烧特性,研究了升温速率对生物质燃烧特性的影响,同时在热天平上对其进行了动力学试验研究.研究表明:生物质燃烧过程大致可以分为3个阶段,即水分析出阶段、挥发分析出燃烧阶段、固定碳燃烧与燃尽阶段:生物质具有着火温度低、燃尽温度低、燃尽率高等优点;随着升温速率的提高,着火温度、各试样挥发分最大释放速率、燃尽温度均呈升高趋势,燃烧特性随升温速率的提高而变好.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,生物质具有较低的活化能,有利于点燃.     

桦甸油页岩燃烧性能的热分析研究

利用热重分析仪在非等温条件下对桦甸油页岩进行了燃烧试验。考察了粒径、升温速率、样品种类等因素对油页岩燃烧特性的影响。采用积分法（C-R法）获得了油页岩的燃烧动力学参数。结果表明，油页岩的燃烧性能随着其挥发分含量的增大而变好，且在燃烧过程中油页岩的表现活化能变化很大，对于不同的燃烧温度范围可用不同的反应级数来描述，在燃烧前期反应级数为1级，而燃烧后期反应级数为3．5级。     

劣质重油掺水燃烧工业性实验研究

该文介绍了作者在德国ＳＡＡＣＫＥ公司所进行的劣质重油掺水燃烧工业性实验研究。该实验是一台容量为６吨／时的火管锅炉上采用ＳＫＶＪ６０转杯燃烧机进行的。通过先进的测试手段和仪器获得可靠数据，然后通过计算得到最佳掺水率及其相应的节能效应和环境效益。