控制捣固焦炉装煤烟尘的工艺途径探讨

详细介绍了国内已经投产的对捣固焦炉的炉顶装煤烟尘和机侧炉头装煤烟尘进行控制的工艺方法,探讨了其他可能采用的装煤烟尘治理方法及其实施的可能性。从合理利用资源的角度,指出了捣固焦炉装煤烟尘治理工艺的发展方向。     

捣固焦炉装煤消烟除尘技术的改造

邹平焦化厂有72孔JND-Ⅱ型捣固式侧装煤焦炉两座,炭化室高度为4.3m,并配有湿式装煤消烟除尘车1套.由于消烟除尘车除尘效果不好,所以装煤时机侧炉门逸出大量荒煤气(冒烟时间105s左右,俗称"黄烟"),消烟除尘车排除的烟尘有时是黑烟,烟气燃烧不完全,烟尘排放不达标,严重影响周围环境.     

焦炉节能型除尘控制系统的应用

在焦炉烟尘中,装煤和出焦散发的烟尘最大,占焦炉污染量的80%以上。出焦时散发的烟尘主要有以下4种:     

顶装焦炉装煤烟尘治理存在的问题及改进

分析了顶装焦炉装煤烟尘治理存在的问题及原因,并提出了对装煤孔进行有效密封的治理方案,介绍了新型顶装焦炉无烟装煤技术,采用该技术后效果良好。     

7.63m焦炉无烟装煤模式优化

分析了7. 63m焦炉装煤车装煤作业存在的主要问题,提出了从装煤量计算方式、平煤控制方式、二次补煤设定、装煤时间控制、平煤杆结构优化方面对7. 63m焦炉装煤模式进行优化,提高了装煤运行的稳定性,增加了装煤量,降低了余煤量,稳定了煤线,减少了烟尘外逸。     

大型捣固焦炉机侧烟尘治理新措施

介绍了新泰正大6.78 m捣固焦炉项目采用的焦炉装煤烟尘治理技术。根据环保要求,捣固焦炉需增加机侧除尘,提出了机侧烟尘治理的新方向,将机侧推焦与装煤合并为一个除尘系统,统一治理机侧炉门外逸烟尘。     

邯宝焦化厂7m焦炉烟尘治理措施

对7m焦炉烟尘产生的原因进行分析,介绍了焦炉装煤过程、出焦过程烟尘的治理对策,同时对现有部分设施进行改造,使烟尘治理取得较好效果。     

焦炉装煤推焦全干式除尘

介绍了焦炉装煤推焦过程所产生烟尘的存在形式以及治理这些烟尘的方法。讨论了带燃烧室全干式装煤除尘的过程、原理、控制参数、主要设备特征及运行效果。     

焚烧法治理装煤烟尘工艺在攀钢捣固焦炉的应用

对国内几种典型的治理焦炉装煤烟尘的工艺进行了介绍,并分析了几种工艺的优缺点。根据攀钢炼铁厂3#、4#焦炉装煤除尘运行情况及现有问题,选用"焚烧+水洗"方式对焦炉装煤除尘工艺进行改造,取得了明显效果,装煤除尘吸力显著提高,除尘效果明显改善,达到排放标准。     

捣固焦炉装煤烟尘治理的新途径

介绍了捣固焦炉的几种除尘方式,重点阐述了以燃烧、强制混合吸附为主,滤袋喷涂保护为辅的装煤烟尘治理工艺。该除尘工艺已成功地应用于5.5m捣固焦炉的烟尘治理,工艺中还应用了混合吸附、单向溢流回喷等多项新技术,解决了以往捣固焦炉装煤烟尘粘结滤袋的难题。     

Catalytic oxidation kinetics of iron-containing carbon particles generated by spraying ferrocene-mixed with diesel fuel into a hydrogen-air diffusion flame

Kinetic measurements of the catalytic oxidation of iron-containing soot particles were made for a better understanding of the role of catalytic particles in the initiation of soot oxidation. Carbon-based iron-containing soot particles were generated by spraying ferrocene-mixed with diesel fuel into an oxy-hydrogen flame. A commercial carbon black was used as a standard. Their oxidative kinetics and physico-chemical characteristics were measured by thermogravimetric analysis, secondary ion mass spectrometry, X-ray diffraction, gas-cell Fourier-transform infrared spectroscopy, induced coupled plasma-atomic emission spectroscopy, and high-resolution transmission electron microscopy. It was found that a tiny amount of ferrocene led to a significant reduction in both the on-set temperature and the activation energy of soot oxidation. Catalytic oxidation occurred in two consecutive steps, as temperature increased. The initiation of oxidation, even with an addition of ferrocene, was controlled mainly by surface oxygen complexes and partly by the long-range crystalline order of the carbon graphene layer. However, once catalytic oxidation began, the progress of the reaction was mainly determined by the amount of ferrocene that was added.     

生物质热解碳烟的研究进展

碳烟是燃料不完全燃烧或气化形成的纳米级碳质颗粒,是空气中细颗粒物PM_2.5的主要来源之一,也是仅次于CO₂的温室效应主要贡献源之一。碳烟的生成会降低生物质热转化过程中的能量利用效率以及气化过程中合成气的品质。作为生物质热化学转化过程的初始步骤,热解碳烟的生成特性、形成机理和减排方法对转化过程中碳烟的控制具有指导意义。本文从生物质热解碳烟的取样、排放特性、理化性质、生成机理及减排措施等方面进行了综述。着重介绍了热解碳烟的产率、化学组成、微观样貌、内部结构和反应性等,总结了原料特性及热解工况对碳烟产率和反应性的影响,汇总了当前调控热解碳烟排放的主要措施。指出目前针对生物质热解碳烟前体的形成及演化转变机理仍不明确,热解碳烟的氧化反应机理研究鲜有报道。此外,热解碳烟生成受原料类型和热解工况等诸多因素影响,当前研究多为单因素的影响分析,缺乏针对碳烟排放的多因素耦合优化研究。     

中国炭素工业生产节能减排主要技术浅析

重点分析了炭素生产过程中的主要节能和减排技术,包括生产设备、生产工艺、余热利用技术以及生产过程中的烟尘处理技术;并指出了我国炭素生产节能减排技术的研究重点和发展趋势.     

Effect of EGR and injection timing on combustion and emission characteristics of split injection strategy DI-diesel engine fueled with biodiesel

In this study, the effect of injection timing and EGR rate on the combustion and emissions of a Ford Lion V6 split injection strategy direct injection diesel engine has been experimentally investigated by using neat biodiesel produced from soybean oil. The results showed that, with the increasing of EGR rate, the brake specific fuel combustion (BSFC) and soot emission were slightly increased, and nitrogen oxide (NO_x) emission was evidently decreased. Under higher EGR rate, the peak pressure was slightly lower, and the peak heat release rate kept almost identical at lower engine load, and was higher at higher engine load. With the main injection timing retarded, BSFC was slightly increased, NO_x emission was evidently decreased, and soot emission hardly varied. The second peak pressure was evidently decreased and the heat release rate was slightly increased.     

Thermal degradation of epoxy resin/carbon fiber composites: Influence of carbon fiber fraction on the fire reaction properties and on the gaseous species release

The thermal degradation of epoxy resin/carbon fiber composites has been performed in ISO 5660 standard cone calorimeter using a piloted ignition. Two kinds of composites that differ by their volume fractions in carbon fiber (56 and 59 vol.%) were tested in this study. The cone calorimeter irradiance level was increased up to 75 kW m^?2 to characterize the carbon fiber volume fraction influence on the composite thermal degradation. Thus, main flammability and combustibility parameters were determined and calculated such as mass loss, mass loss rate, ignition time, thermal response parameter, ignition temperature, thermal inertia, and heat of gasification. As a result, all the characteristic parameters for the thermal resistance of composites were decreased when the carbon fiber volume fraction increased. Moreover, the main gaseous products (such as NO, CO, CO₂, HCN, H₂O, and lightweight hydrocarbons) emitted as well as the oxygen consumption during the composite thermal decomposition were also quantified simultaneously with a portable gas analyzer and a Fourier transform infrared spectrometer. The main species emission yields calculated from the gas analysis results increased slightly when the carbon fiber volume fraction was increased in the initial sample. The epoxy composite was represented as a sooty material with a significant production of soot particles during the combustion process. Furthermore, heat release rate, total heat release, and effective heat of combustion were calculated by using the oxygen consumption calorimetry technique. The results obtained showed that a small increasing of composite carbon fiber amount induced a sharp decrease of heat release rate and total heat release. Copyright © 2014 John Wiley & Sons, Ltd.     

层燃炉煤燃烧碳黑形成规律的实验研究

设计了可移动式-固定床块煤燃烧实验台,进行了层燃炉块煤燃烧碳黑生成规律的研究。结果表明,随着温度的升高,碳黑和焦油的生成量先增加后减少,呈马鞍形,这是碳黑、焦油形成过程与氧化过程相互竞争的结果,高温有利于减少碳黑的排放;随着气体停留时间的延长,碳黑和焦油的生成量减少;高挥发分煤不完全燃烧时,碳黑的生成量较高;随着氧量比的增大,碳黑和焦油的生成量逐渐减少;当氧量为理论燃烧煤所需氧量的0.9倍时,没有碳黑和焦油生成。     

Influence of two-stage injection and exhaust gas recirculation on the emissions reduction in an ethanol-blended diesel-fueled four-cylinder diesel engine

The purpose of this study is to investigate the effects of two-stage injection and exhaust gas recirculation (EGR) on the spray behavior and exhaust emission characteristics in diesel-ethanol fuel blends fueled four-cylinder diesel engine. The spray behavior is analyzed from the spray development process, spray tip penetration, and spray cone angle, which are obtained from the spray images. The combustion and exhaust emission characteristics are measured from the four-cylinder diesel engine with a common-rail injection system.The experimental results revealed that the increase of the pilot injection amount causes the fast development of the injected pilot spray, and the penetration difference among the main sprays is less than that among the pilot sprays. An increase in the ethanol blending ratio causes an increase in the ignition delay in the pilot combustion, but the main combustion is little influenced by the ethanol blending. The increase in the pilot injection amount shows the reduction effects of NO_x emissions when the pilot injection timing is advanced beyond BTDC 20°. The concentration of soot emissions shows a decreasing pattern according to the advance of the pilot injection and the decrease in the pilot injection amount. The CO emissions increase with the advance of the pilot injection timing, the increase in the pilot injection amount, and the ethanol blending ratio. In addition, the increase in the ethanol blending ratio and the advance of the pilot injection timing induce an increase in the HC emissions. The increase in the pilot injection amount induces a slight increase in the HC emissions.     

Experimental study of n-butanol additive and multi-injection on HD diesel engine performance and emissions

Experimental study was conducted to investigate the influence of the diesel fuel n-butanol content on the performance and emissions of a heavy duty direct injection diesel engine with multi-injection capability. At fixed engine speed and load, exhaust gas recirculation rates were adjusted to keep NO_x emission at 2.0 g/kW h. Diesel fuels with different amounts (0%, 5%, 10% and 15% by volume) of n-butanol were used. The results show that the n-butanol addition can significantly improve soot and CO emissions at constant specific NO_x emission without a serious impact on the break specific fuel consumption and NO_x. The impacts of pilot and post injection on engine characteristics by using blended fuels are similar to that found by using pure diesel. Early pilot injection reduces soot emission, but results in a dramatic increase of CO. Post injection reduces soot and CO emissions effectively. Under each injection strategy, the increase of fuel n-butanol content leads to further reduction of soot. A triple-injection strategy with the highest n-butanol fraction used in this study offers the lowest soot emission.     

Impact of Fe Content in Laboratory-Produced Soot Aerosol on its Composition,Structure, and Thermo-Chemical Properties

Soot aerosol, which is a major pollutant in the atmosphere of urban areas, often contains not only carbonaceous matter but also inorganic material. These species, for example, iron compounds, originated from impurities in fuel or lubricating oil, additives or engine wear may change the physico-chemical characteristics of soot and hence its environmental impact. We studied the change of composition, structure, and oxidation reactivity of laboratory-produced soot aerosol with varying iron content. Soot types of various iron contents were generated in a propane/air diffusion flame by adjusting the doping amount of iron pentacarbonyl Fe(CO)₅ to the flame. Scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) was combined with cluster analysis (CA) to separate individual particles into definable groups of similar chemical composition representing the particle types in dependence of the iron content in soot. Raman microspectroscopy (RM) and infrared spectroscopy were applied for the characterization of the graphitic soot structure, hydrocarbons, and iron species. For the analysis of soot reactivity, temperature-programmed oxidation (TPO) was used. It is demonstrated that iron is most dominantly present in the form of amorphous Fe (III) oxide crystallizing to hematite α-Fe₂O₃ upon thermal treatment. Iron contaminations do not change the soot microstructure crucially, but Fe(CO)₅ doping of the flame impacts hydrocarbon composition. Soot oxidation reactivity strongly depends on the iron content, as the temperature of maximum carbon (di)oxide emission T _max follows an exponential decay with increasing iron content in soot. Based on the results of the thermo-chemical characterization of laboratory-produced internally mixed iron-containing soot, we can conclude that iron-containing combustion aerosol samples cannot be characterized unambiguously by current thermo-optical analysis protocols.

Copyright 2012 American Association for Aerosol Research     

Direct Measurement of Aircraft Engine Soot Emissions Using a Cavity-Attenuated Phase Shift (CAPS)-Based Extinction Monitor

The optical properties of soot particles in plumes emanating from a high bypass turbofan aircraft engine (V2527) were measured at distances of 40–80 m behind the engine with a cavity-enhanced phase shift (CAPS)-based extinction monitor (known as the CAPS PM_ex) and a multi-angle absorption photometer, both operating at wavelength ～630 nm. Integrated plume measurements from the two instruments were highly correlated with each other (r ² > 0.99, N = 12) and with measured carbon dioxide emission concentrations. Ancillary measurements indicated that the soot particle volume-weighted mobility diameter distribution peaked at 60 nm with a full width at half maximum of ～60 nm. The soot single scattering albedo determined using the absorption and extinction measurements under engine idle conditions was 0.05 ± 0.02 (where the uncertainty represents 2σ precision), in agreement with previous measurements of aircraft exhaust. The engine soot emission index (mass soot per mass fuel burned) for this particular engine, derived from these measurements and a wavelength-specific mass absorption coefficient and the measured in-plume carbon dioxide concentrations, was 225 ± 35 mg kg^?1 at engine idle conditions. These results plus more limited data collected from in-use aircraft on the runway indicate that the CAPS extinction monitor can provide (with an appropriate albedo correction) a credible measurement of the engine soot emission index in situations where the time response and sensitivity of particle absorption monitors are not otherwise sufficient.