液体燃料的预蒸发燃烧技术—应用着火延迟现象实现液体燃料的预蒸发

本文阐述了液体燃料的预蒸发燃烧技术原理,其中着重介绍了利用着火延迟现象实现液体资料的预蒸发技术和采预蒸发技术的液体燃烧器,并指出液体燃料的预蒸发燃烧具有高效率,低噪音,低污染,特别是低NOX排放和易调节等优点。     

利用冷焰现象实现轻油的预蒸发燃烧

介绍一种燃烧液体燃料的新技术－预蒸发燃烧技术,通过分离液体燃料的蒸发过程和燃烧过程,实现液体燃料的“气体化”燃烧。重点介绍了利用液体燃料着火前存在的冷焰燃烧现象实现燃料预蒸发的技术原理。与传统的燃烧技术相比,轻油的预蒸发燃烧具有高效率、低噪音、低有害污染物,特别是NOx排放和易调节等优点。     

液体燃料的预蒸发燃烧技术--应用着火延迟现象实现液体燃料的预蒸发

本文阐述了液体燃料的预蒸发燃烧技术原理,其中着重介绍了利用着火延迟现象实现液体燃料的预蒸发技术和采用预蒸发技术的液体燃烧器.并指出液体燃料的预蒸发燃烧具有高效率,低噪音,低污染,特别是低NOx排放和易调节等优点.     

轻油的预蒸发燃烧——预蒸发燃烧技术原理及实践

介绍了液体燃料预蒸发燃烧的技术原理,着重介绍了利用轻油燃烧前存在的着火延迟现象和着火前存在的冷焰燃烧现象实现轻油预蒸发的技术原理,轻油的预蒸发燃烧具有高效率,低噪音排放,低污染,特别是低NOx排放和易调节等特点。     

重油工业锅炉燃烧中存在的问题及对策

本文讨论了重油工业锅炉燃烧中存在的问题以及改善重油燃烧的若干技术措施，探讨并重点介绍了预蒸发燃烧技术和利用预蒸发技术燃烧重油的可行性．     

轻油预蒸发燃烧中的稳焰技术

介绍液体燃料预蒸发燃烧的技术原理,分析轻油预蒸发燃烧中的火焰稳定问题,并重点介绍目前在实现轻油预蒸发燃烧中所采用若干稳焰措施。     

基于液体燃料的多孔介质燃烧技术研究现状

对国内外近年来关于多孔介质燃烧技术在液体燃料燃烧领域的实验及数值模拟研究做了较为全面的综述和分析。分析表明:多孔介质燃烧技术为液体燃料提供了一种可能的先进燃烧方式。相较于传统自由空间内的火焰燃烧,多孔介质燃烧技术可改善液体燃料的雾化、蒸发,获得低排放、高稳定性、宽负荷比的燃烧表现。该技术在燃油锅炉、燃气轮机、斯特林发动机等领域拥有广阔的应用前景。     

基于液体燃料的多孔介质燃烧技术研究现状

对国内外近年来关于多孔介质燃烧技术在液体燃料燃烧领域的实验及数值模拟研究做了较为全面的综述和分析。分析表明:多孔介质燃烧技术为液体燃料提供了一种可能的先进燃烧方式。相较于传统自由空间内的火焰燃烧,多孔介质燃烧技术可改善液体燃料的雾化、蒸发,获得低排放、高稳定性、宽负荷比的燃烧表现。该技术在燃油锅炉、燃气轮机、斯特林发动机等领域拥有广阔的应用前景。     

汽车加热器燃烧理论研究

本文主要介绍了指导蒸发混合式汽车燃油加热器设计的蒸发预燃三阶段理论。其解决的核心问题是分离液体燃料的蒸发气化及其与空气中氧的掺混过程和燃烧过程。在该理论的指导下设计出蒸发混合式汽车燃油加热器,经性能试验测试综合性能达到GB10908—1989《燃油加热器技术条件》的要求。蒸发预燃三阶段理论有较高的应用价值。     

汽车加热器燃烧理论研究

本文主要介绍了指导蒸发混合式汽车燃油加热器设计的蒸发预燃三阶段理论.其解决的核心问题是分离液体燃料的蒸发气化及其与空气中氧的掺混过程和燃烧过程.在该理论的指导下设计出蒸发混合式汽车燃油加热器,经性能试验测试综合性能达到GB10908-1989 <燃油加热器技术条件>的要求.蒸发预燃三阶段理论有较高的应用价值.     

Comparison of staged combustion properties between bituminous coals and a low-rank coal; Fiber-shaped crystallized carbon formation,NOx emission and coal burnout properties at very high temperature

Previously, we developed a new-concept for a drop-tube furnace in order to investigate staged combustion properties for pulverized coals. Two high-temperature electric furnaces were connected in series. Coal was burnt under fuel-rich conditions in the first furnace, then, staged air was supplied at the connection between the two furnaces. In the present study, we investigated influence of burning temperature on NOx emission and combustion efficiency by using the furnace. The influence of the temperature differed between hv-bituminous coals and a sub-bituminous coal. For the hv-bituminous coals, combustion efficiency was improved when burning temperature in the fuel-rich region rose. When combustion efficiency was improved, NOx emission decreased. The NOx reduction reaction in the fuel-rich region was promoted by increasing the burning temperature in this region. On the other hand, NOx emission increased for the sub-bituminous coal when the temperature was higher than 1800 K. Usually, combustion efficiency was increased with burning temperature. However, combustion efficiency lowered for the sub-bituminous coal when burning temperature was higher than 1900 K. We observed the ash obtained by this temperature condition using Scanning Electron Microscope (SEM) and, Transmission Electron Microscope (TEM) and observed fiber shaped carbon. The difference in NOx properties was derived as a difference of hydrocarbon concentration. For low-rank coals (sub-bituminous or lignite), the hydrocarbon formation rate was smaller than that for hv-bituminous coals. When the hydrocarbon contribution to the NOx reduction reaction was large, NOx emission decreased with increasing burning temperature; however, hydrocarbon content in volatile matter was small for low-rank coals.     

燃煤电站锅炉中的低NOx燃烧技术

本文针对我国NOx的排放情况及其主要来源，分析了NOx的生成途径。根据生成机理的不同比较分析了各种低NOx燃烧技术，包括低氧燃烧、浓淡燃烧、分级燃烧、废气再循环等技术。由于我国NOx排放以燃煤电站锅炉为主，因此本文主要讨论各种低NOx燃烧技术在电站锅炉中的应用。同时，对低NOx燃烧技术在工业锅炉及其它燃烧过程中的应用作了简要介绍。     

Combustion characteristics of micron-sized aluminum particles in oxygenated environments

Experimental data describing combustion of micron-sized aluminum particles as a function of their size are limited. Often combustion characteristics are derived indirectly, from experiments with aerosolized powder clouds. In a recently developed experiment, micron-sized particles cross two laser beams. When each particle crosses the first, low-power laser, it produces a scattered light pulse proportional to the particle diameter. The second, powerful CO₂ laser beam ignites the particle. The optical emission pulse of the burning particle is correlated with its scattered light pulse, so that the combustion characteristics are directly correlated with the size for each particle. In this work, emission signatures of the ignited Al particles are recorded using an array of filtered photomultipliers to enable optical pyrometry and evaluate the molecular AlO emission. Processing of the generated data for multiple particles is streamlined. Experiments are performed with spherical aluminum powder burning in atmospheric pressure O₂/N₂ gas mixtures with the oxygen concentrations of 10%, 15%, and 21% (air). In air, the AlO emission peaks prior to the maximum in the overall emission intensity, and the latter occur before the maximum of the particle temperature. The temperatures at which particles burn steadily increase with particle size for particles less than 7.4 μm. For coarser particles, the flame temperature remains constant at about 3040 K. In the gas mixture with 15% O₂, the flame temperatures are observed to increase with particle size for the entire range of particle sizes considered, 2–20 μm. At 10% O₂, the flame temperatures are significantly lower, close to 2000 K for all particles. The intensity of AlO emission decays at lower oxygen concentrations; however, it remains discernible for all environments. The results of this study are expected to be useful for constructing the Al combustion models relaxing the assumption of the steady state burning.     

Progress and recent utilization trends in combustion of Chinese oil shale

The gradual decrease in conventional energy resources, and the growth of heavy industry, have placed great pressure on China's energy supplies. As a result of technological development, clean and diverse energy utilization facilities have become available in the energy market. Oil shale with combustible organic materials is widespread throughout the earth; many researchers have been motivated to investigate efficient means to use oil shale as an alternative energy as soon as possible.

In China, the conventional utilization of oil shale is concentrated mainly on oil shale retorting, and burning oil shale in pulverized furnaces, or bubbling fluidized beds. To improve the availability of oil shale, many specialists have advocated burning oil shale in a circulating fluidized bed (CFB), which has a satisfactory combustion efficiency, low NO_X and SO₂ emission, adaptability to low-grade coal, etc. In Huadian, China, a plant incorporating three units of 65 t h⁻¹ oil shale-fired CFB began successful commercial operation in 1996, proving that burning oil shale in a CFB produces both high combustion efficiency and environmental protection. For effective utilization of oil shale, its pyrolysis and combustion characteristics, emission performance of gaseous pollutants from an oil shale-fired CFB pilot setup, co-combustion characteristics of oil shale and high sulfur coal—as well as the operating performance of the Huadian CFB boiler—were further studied. The resulting experimental data and theoretical analysis prove that oil shale resources have significant potential use in the combustion field.

This paper introduces these fundamental characteristics and the industrial application of oil shale in combustion. Three projects are recommended for the future use of oil shale, based on the current status of energy and the characteristics of oil shale: (1) co-combustion of oil shale and high sulfur fuel for furnace desulfurization; (2) large-scale development of oil shale-fired CFBs; (3) a comprehensive oil shale utilization project to produce shale oil, burn oil-shale semicoke in a CFB boiler to generate electricity and supply heat, and produce building materials with oil shale ash.     

Heat transfer effects in nano-aluminum combustion at high temperatures

Recent measurements of nano-aluminum combustion in which burning time and peak particle temperature are measured simultaneously have suggested that heat transfer models currently used for burning nanoparticles may significantly overestimate heat losses during combustion. By applying conventional non-continuum heat transfer correlations to burning nano-aluminum particles, the observed peak temperatures, which greatly exceed the ambient temperature, should only be observable if the burning time were very short, of the order of 1 μs, whereas the observed burning time is two orders of magnitude larger. These observations can be reconciled if the energy accommodation coefficient for these conditions is of the order of 0.005, which is the value suggested by Altman, instead of approximately unity, which is the common assumption. Experimental data obtained in the heterogeneous shock tube under a wide array of conditions are compared with basic heat transfer models, and the agreement of both peak temperature values and emission intensity traces for low energy accommodation coefficients supports the hypothesis of Altman and co-workers.     

新型低污染燃气受控脉动燃烧技术的应用研究

在工业炉上使用新型低污染燃气受控脉动燃烧技术具有降低NOx排放量、节能、温度均匀等优点。本实验采用成对的预混型调温高速烧嘴实现该技术,大幅度降低CO排放量,使该技术更为完善,有广阔的应用前景。     

一次风率及循环废气率变化对燃油锅炉运行中氮氧化物生成的影响

研究空气分级和废气循环燃烧等方式对油燃烧中NOx 生成的影响。实验发现 :分级燃烧对于燃料氮的转化有抑制作用 ,而且对含氮量较高的油燃料效果较明显 ,不论燃烧器功率如何 ,降低一次风率总使得NOx 的生成量减少 ;当一次风率占总过量空气系数的 50 %左右时 ,燃料氮的转化率存在一个最小值 ,而后随着一次风率的提高而增大并趋于一常数 ;增加废气循环率能降低油燃烧中NOx 的生成量 ,而且对于含氮量较低的油效果较明显 ,随着废气循环率增加 ,NOx 生成量的降幅趋缓并带来火焰稳定问题 ,因此存在有一个最佳废气循环率 ;废气循环燃烧会增大燃料氮的转化率 ,而且在一次风率较小情况下表现明显     

Staged combustion properties for pulverized coals at high temperature

Staged combustion properties for pulverized coals have been investigated by using a new-concept drop-tube furnace. Two high-temperature electric furnaces were connected in series. Coal was burnt under fuel-rich conditions in the first furnace, then, staged air was supplied at the connection between the two furnaces. Reaction temperature (1800–2100 K) and time (1–2 s) were similar to those used in actual boilers. When coal was burnt at the same stoichiometric ratio as in actual boilers, similar combustion performance values as for actual boilers were obtained regarding NO_x emission and carbon in ash. The most important factor for low NO_x combustion was to raise the combustion temperature above the present range (1800–2100 K) in the fuel-rich zone. The NO_x emission was significantly increased with decrease of burning temperature in the fuel-rich zone when the temperature was lower than 1800 K. But, NO_x emission was cut to around 100–150 ppm, for sub-bituminous coal and hv-bituminous coal, in the latest commercial plants by forming this high-temperature fuel-rich region in the boilers. If the temperature and stoichiometric ratio could be set to the most suitable conditions, and, burning gas and air were mixed well, it would be possible to lower NO_x emission to 30–60 ppm (6% O₂). The most important NO_x reduction reaction in the fuel-rich zone was the NO_x reduction by hydrocarbons. The hydrocarbon formation rate in the flame was varied with coal properties and combustion conditions. The NO_x was easily reduced when coals which easily formed hydrocarbons were used, or, when burning conditions which easily formed hydrocarbons were chosen. Effects of burning temperature and stoichiometric ratio on NO_x emission were reproduced by the previously proposed reaction model. When solid fuel was used, plant performance values varied with fuel properties. The proposed drop-tube furnace system was also found to be a useful analysis technique to evaluate the difference in combustion performance due to the fuel properties.     

废轮胎热解油特性及其燃烧应用

随着石油资源的日益枯竭及废轮胎数量的日益增多,利用废轮胎热解制取燃料油对缓解能源供应紧张局面,充分利用废弃资源都具有重要意义.废轮胎热解油具有热值高、灰分低、粘度低和残炭值低等优点,但也存在整体性能较柴油差的缺陷.与柴油混合作为发动机燃料使用的结果表明,废轮胎热解油可以作为重柴油使用;炉内燃烧试验表明.废轮胎热解油污染物排放量较柴油高.探索合适的废轮胎热解工艺,提高废轮胎热解油的品质,是将废轮胎热解油直接作为燃料油使用须研究的主要课题之一.