稻壳混合贫煤燃烧对SO2排放的影响

本文利用循环流化床实验平台,分析稻壳混煤燃烧对SO2排放的影响.将稻壳与贫煤按不同质量比制成混合燃料,在流化床锅炉中燃烧,采集炉温及烟气中SO2浓度等数据进行分析.结果表明,当燃烧温度恒定时,SO2的排放量随着燃料中稻壳所占比重增加而降低;当燃料中稻壳所占比重恒定时,SO2的排放量随着燃烧温度的升高而增加.     

循环流化床中石油焦与煤混合燃烧SO2排放特性研究

在一座0．5MW1循环流化床热态试验装置上进行了石油焦与煤混合燃烧试验，研究了烟气中SO2的排放特性．对于石油焦与煤不同燃料配比，不同锅炉运行参数，如过量空气系数、床温、一次风率、Ca／S比等对烟气中SO2排放浓度的影响规律进行了研究．试验表明：对不同配比的燃料，随过量空气系数和一次风率的增大，SO2排放浓度降低；对于床温有一最佳温度，其SO2排放浓度最低；随Ca／S增大，SO2排放浓度降低。     

流态化燃烧NO、N2O和SO2同步排放试验研究

研究了热态流化床实验台中燃烧褐煤、烟煤和无烟煤时SO_2、NO和N_2O同步排放浓度随过量空气系数、燃烧温度和钙硫比的变化规律。试验中过量空气系数变化范围为0.8～1.8,燃烧温度变化范围为750～950℃,钙硫比变化范围为0～3。结果表明:过量空气系数增加时NO和N_2O的排放浓度增加,SO_2排放浓度先增加后降低;燃烧温度增加时NO排放浓度增加,N_2O排放浓度降低,SO_2的排放浓度增加;加入碳酸钙后NO排放量增加,N_2O和SO_2的排放量减少。加入碳酸钙后可以有效降低SO_2排放,同时会使NO排放增加、N_2O排放降低;烟煤、无烟煤和褐煤燃烧时NO、SO_2和N_2O随过量空气系数的变化规律存在差别。     

烟煤及其混煤高温燃烧时SO2生成特性的试验研究

在一维沉降炉上对某电厂燃用的几种烟煤及其混煤进行了试验研究,通过改变炉膛温度,过量空气系数,二次风风温,一、二次风配比,给粉量等,分析了这些因素的变化对这几个煤种按不同掺混比组成的混煤燃烧时SO2排放量的影响,为大型电厂锅炉高效清洁燃烧提供了理论依据.     

O2/CO2气氛下生物质混煤燃烧SO2排放特性的实验研究

在水平管式炉上通过在线烟气分析仪研究了O2/CO2气氛下生物质混合比例、温度、燃烧气氛及氧浓度对生物质混煤SO2排放特性的影响规律。结果表明,O2/CO2气氛下,随着生物质混合比例的增大,生物质混煤SO2释放峰值减小,SO2排放完毕的时间减少,SO2的排放量降低;随着温度的升高,生物质混煤SO2的排放量增加。O2/CO2和O2/N2气氛下随着氧浓度的增大,生物质混煤SO2的排放量均增加。相同氧浓度时,O2/CO2气氛下生物质混煤SO2的排放量略小于O2/N2气氛下的情况,其降低幅度约为5%左右。     

微藻与木屑混合燃烧SO2与NO排放特性试验研究

采用NBW-A-1000生物质燃烧及后处理分析试验系统对微藻与木屑成型燃料在不同温度、不同配比混燃时SO2与NO排放特性进行在线测量,分析不同条件下SO2与NO的瞬时排放浓度及S、N转化率.结果表明:与微藻相比,木屑单独燃烧时SO2与NO瞬时析出浓度峰值非常小,析出峰出现的时间较迟;随着混合微藻比例的增大,SO2的生成...     

煤粉/生物质恒温混燃过程中SO2排放特性

通过自制SO2监测实验系统对煤粉/生物质进行恒温混燃SO2监测实验,探讨了掺混比、煤种、生物质种类以及温度等因素对煤粉/生物质恒温混燃SO2排放特性的影响规律.研究表明:燃烧初期,燃烧进行的越快,SO2析出率越高.随着燃烧的进行,生物质掺混比增加有利于燃料的SO2析出率降低;SO2析出率较高的煤粉掺混生物质降低SO2析出的作用效果比SO2析出率较低的煤粉掺混更明显;掺混含硫量高的生物质在燃烧初期降低燃料SO2析出作用效果明显.随着燃烧的进行,生物质灰分含量的影响作用逐渐增大,灰分含量越高,降低效果越明显;温度升高总是有利于混合燃料的SO2析出率增加,且温度区间越高燃料的SO2析出率增加越显著.     

硫磺回收装置SO2排放超标原因分析及改进措施

大连石化27×104t/a硫磺回收装置按三系列设置,单套公称规模为9×104t/a,单系列操作弹性为30%~100%,年开工时数为8400h。该装置处理的原料为再生酸性气和汽提酸性气。再生酸性气由溶剂再生装置、硫磺回收装置尾气处理和三催化酸性水汽提装置来的酸性气组成;汽提酸性气来自于酸性水汽提装置。装置于2008年8月5日开车成功,产出合格硫磺成品,尾气排烟中SO2排放含量在50~200mg/m3。随着运行时间的增加,开工一年后,装置SO2排放含量高达943mg/m3,即将超过环保标准（960mg/m3）。从提高硫磺回收率、增加尾气加氢效果、保证尾气吸收单元正常运行,以及提高尾气溶剂硫化氢吸收效果方面入手,总结出降低尾气排烟SO2含量的有效方法。实践证明,维持合适的燃烧炉风气比、高的转化器入口温度、适当的加氢反应氢气含量,将有效降低尾气排烟中的SO2含量。     

循环流化床中谷壳与煤共燃降低SO2排放实验研究

在循环流化床实验台上,对谷壳与煤共燃降低SO2的排放进行了实验,着重研究了床温、过量空气系数对SO2生成特性的影响.实验表明：谷壳与煤共燃能够降低煤燃烧的SO2生成量50%以上;加入谷壳的比例存在一个最佳范围,不超过30%;共燃时SO2的生成量随床温的升高而增加,SO2的减排率随床温的升高呈起伏变化,温度为850℃时减排率最大;共燃时过量空气系数变化对SO2的生成量无显著影响.     

烧结熔剂对焦粉燃烧行为及其SO2排放的影响

铁矿烧结工序作为钢铁行业SO2排放的主要来源,在钢铁行业超低排放形势下高效低成本减少其SO2排放迫在眉睫.烧结过程中固体燃料的燃烧会产生大量SO2,而料层内的熔剂会影响SO2排放.基于此,采用微型烧结装置分别研究生石灰、石灰石、白云石等烧结常用熔剂对焦粉燃烧行为及其SO2排放的影响.结果 表明,配加烧结熔剂能有效提高焦粉的燃烧速率,且显著降低SO2排放,其中,配加生石灰脱硫效果显著高于配加石灰石和白云石时的情形.配加生石灰时,SO2质量分数最大值和排放总量分别降低约68.38％、70.89％.然而,相比于配加生石灰情形,配加2种碳酸盐熔剂能显著促进焦粉的燃烧.因此,在烧结混合料中应适当提高生石灰的配比,减少石灰石和白云石的配比,能有效减少烧结工序SO2的排放.     

市政污泥流化床掺烧生物质的NO与SO2排放特性研究

为了探究市政污泥燃烧过程中的气态污染物排放特性,在30 kW鼓泡流化床实验台上进行了市政污泥的燃烧实验,研究燃烧温度、二次风率、秸秆掺混比等参数对气态污染物排放特性的影响。结果表明：燃烧温度的升高会显著提高NO与SO₂的排放;提高二次风率使NO排放浓度减少,SO₂排放浓度增加;由于生物质中较低的N、S含量以及生物质与污泥燃烧的协同作用,污泥掺烧生物质能够有效地减少NO与SO₂的排放;秸秆占比由0提升至40%,NO由289 mg/m³下降至140 mg/m³,而SO₂排放浓度也从3 949 mg/m³下降至1 725 mg/m³;污泥掺烧秸秆时,NO与SO₂的整体排放特性与污泥单独焚烧相似,掺烧秸秆能够加快整体的燃烧速率,并加强燃烧气氛的氧化性,进而影响气态污染物的排放。     

玉米秸秆颗粒燃料燃烧特性的试验研究

为了研究玉米秸秆颗粒燃料的燃烧特性,以一个小型反烧单元体炉为试验装置,分别进行了不同料层、不同水分、不同空气量下的燃烧试验,了解其燃烧特性,如点火时间、燃烧时间、燃烧过程及燃烧后的结渣现象。试验结果表明,玉米秸秆颗粒燃料易点燃,燃烧温度高,但燃烧时间短,结渣严重;料层高的玉米秸秆颗粒燃料燃烧时间相对长,但燃烧温度低,轻微结渣;干燥处理过的玉米秸秆颗粒燃料点火时冒黑烟现象明显减轻;加大燃烧过程的空气量时,玉米秸秆颗粒燃料不结渣。     

Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

Effects of Fischer-Tropsch (F-T) diesel fuel on the combustion and emission characteristics of a single-cylinder direct injection diesel engine under different fuel delivery advance angles were investigated. The experimental results show that F-T diesel fuel exhibits shorter ignition delay, lower peak values of premixed burning rate, lower combustion pressure and pressure rise rate, and higher peak value of diffusion burning rate than conventional diesel fuel when the engine remains unmodified. In addition, the unmodified engine with F-T diesel fuel has lower brake specific fuel consumption and higher effective thermal efficiency, and presents lower HC, CO, NO _x and smoke emissions than conventional diesel fuel. When fuel delivery advance angle is retarded by 3 crank angle degrees, the combustion duration is obviously shortened; the peak values of premixed burning rate, the combustion pressure and pressure rise rate are further reduced; and the peak value of diffusion burning rate is further increased for F-T diesel fuel operation. Moreover, the retardation of fuel delivery advance angle results in a further significant reduction in NO _x emissions with no penalty on specific fuel consumption and with much less penalty on HC, CO and smoke emissions. __________ Translated from Chinese Internal Combustion Engine Engineering, 2007, 28(2): 19–23 [译自: 内燃机工程]     

煤与污泥混合物在不同温度下燃烧时SO_2排放特性研究

选取三种煤与污泥的混合物在不同温度下进行加热,分析其SO2排放特性,本研究中温度分别设置为700℃和1000℃,结果表明不同比例的污泥对混合物SO2排放有着重要影响;同时,不同温度对石炭煤的累积SO2排放量有着一定影响,在700℃下,累积SO2排放量为2000~5000 mL/m3,而在1000℃时,其累积排放量为2500~3500 mL/m3,另外,高温能够加快各混合物SO2产生速率。     

丙烯腈废液焚烧炉改善燃烧与污染排放试验研究

针对丙烯腈装置废液焚化炉燃烧效率低、污染排放大的现状 ,采用重油乳化燃烧、改善燃烧系统及改进操作工况等措施进行了试验研究 ,可明显提高焚化炉的燃烧效率 ,降低NOx 等污染物的生成与排放 ,具有节能和环保的双重效益     

酸雨及SO_2与NO_x污染控制的探讨

叙述了酸雨的分布、酸雨的形成及酸雨的危害等以及中国形成酸雨的主要污染物,提出,控制酸雨和SO2与NOx的建议与措施。     

Preliminary study of trace element emissions and control during coal combustion

Hazardous trace element emissions have caused serious harm to human health in China. Several typical high-toxic trace element coals were collected from different districts and were used to investigate the emission characteristics of toxic trace elements (As, Se, Cr, Hg) and to explore preliminary control methods. Coal combustion tests were conducted in several bench-scale furnaces including drop tube furnace (DTF), circulating fluidized bed (CFB) combustion furnace, and fixed-bed combustion furnace. Calcium oxide was used to control the emission of arsenic and selenium. The granular activated carbons (AC) and activated-carbon fibers (ACF) were used to remove mercury in the flue gas from coal combustion. The chemical composition and trace element contents of ash and particulate matter (PM) were determined by X-ray fluorescence (XRF) spectrometry and inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. The speciation and concentration of mercury were investigated using the Ontario-Hydro method. X-ray diffraction spectrometry (XRD) was used to determine the mineral composition of production during combustion experiments. With the addition of a calcium-based sorbent, arsenic concentration in PM₁ sharply decreased from 0.25–0.11 mg/m³. In fixed-bed combustion of coal, the retention rates of selenium volatiles were between 11.6% and 50.7% using lime. In the circulating fluidized-bed combustion of coal, the content of selenium in ash from the chimney was reduced to one-fourth of its original value and that in leaching water from the chimney decreased by two orders of magnitude using lime. Calcium-based sorbent is an effective additive to control the emission of As and Se during coal combustion. The emission of chromium is influenced by the occurrence mode of Cr in coal. Chromium emission in PM_2.5 during coal combustion is 55.5 and 34.7 μg/m³ for Shenbei coal and mixed Pingdingshan coal, respectively. The adsorptive capacity of granular activated carbon for Hg⁰ is significantly enhanced through ZnCl₂-impregnation. The activated carbon fibers showed decent efficiency in mercury adsorption, on which surface oxygen complex showed positive effects on mercury adsorption.