煤、油页岩和石油焦混烧特性及其动力学

为了充分利用劣质燃料油页岩和难以利用的高硫石油焦,以煤、劣质燃料油页岩及高硫燃料石油焦的混合燃料为研究对象,采用热重-差热的试验方法和差减微分法,对其混烧特性曲线和混烧特性机理进行分析,计算出试样各种燃烧特性参数及燃烧动力学参数。结果表明:煤、油页岩、石油焦的质量比为1∶6∶3的混烧试样S7的DTG曲线先后出现挥发分的析出着火燃烧峰和剩余固定碳的着火燃烧峰;煤、油页岩、石油焦的质量比为6∶3∶1的混烧试样S4的可燃特性指数及着火特性指数均大于油页岩及石油焦的值,而且混合试样的燃尽指数均大于煤及石油焦的值,同时,混合样品的综合燃烧特性指数均大于油页岩的值;试样S4的活化能最小,该混合试样的燃烧反应最容易进行。只要煤、油页岩及石油焦混合比例适当,其混合燃烧特性将优于油页岩及石油焦单独的燃烧特性。     

石油焦与煤混烧特性及动力学

以石油焦与煤的混合燃料为研究对象,采用TG—DTG—DSC联用实验技术对混合试样进行了燃烧热重实验。分析了混烧特性曲线,计算了各个燃烧特性指数,并采用差减微分法Freeman—Carroll计算了燃烧反应动力学参数。结果表明：各混合试样均只出现一个位于高温区段的DTG曲线峰和方向向下的DSC曲线的热量释放峰,混合试样的燃烧过程主要是高温阶段焦炭的着火燃烧过程;混合试样s2,S3及S5热量释放相对较少且不集中,燃烧时间长且不完全;混合试样S4及S6的热量释放集中且时间短,燃烧释放的热量相对较多;烟煤含量最多的混合试样s6的着火特性、燃尽特性指数及综合燃烧特性参数均高于其它混合试样以及石油焦的各个相应值,且试样s6的可燃特性指数也大于石油焦的可燃特性指数;混合试样活化能均小于石油焦燃烧的活化能,混合试样比石油焦更易着火燃烧;只要石油焦与煤的混合比例适当,石油焦掺烧烟煤后的燃烧特性优于石油焦单独燃烧特性,此为解决石油焦难以单独燃烧利用提供了方法。     

石油焦与煤粉燃烧性能差异的研究

石油焦作为石油工业副产品,具有低灰分质量分数、高挥发分质量分数、高发热值等特点,但对其燃烧价值的利用还很不充分。文中利用X射线衍射及扫描电镜对石油焦及烟煤和无烟煤进行微观结构的研究,同时利用热重分析方法对其燃烧性能进行系统研究发现:石油焦的芳香片层堆砌结构与无烟煤接近,但其丰富的气孔结构又有利于改善其燃烧过程。无烟煤中加入石油焦后,着火点温度从527℃降低到482.6℃;总质量分数从71.95%提高到76.82%,其燃烧效率得到提高。     

平板玻璃熔窑燃料浅析

通过对目前已成功用于我国玻璃熔窑的天然气、重油、煤焦油、焦炉煤气、发生炉煤气、石油焦粉6种燃料的物化性质、燃烧状态、燃烧产物及对玻璃熔化质量的影响、对熔窑耐火材料的烧蚀、烟气含硫量粉尘量等方面进行对比分析,阐述了各自的优缺点,提出了应重视的问题,以便于玻璃企业对燃料品种作出判断和选择。     

石油焦粉在玻璃熔窑直接燃烧代替重油的适用性分析

在玻璃企业能源成本由于燃油成本的增加而不断上涨的形势下,通过讨论石油焦在玻璃熔窑上的适用性,提出了石油焦在玻璃熔窑中代替重油的可能性,并针对实际应用提出采用石油焦高温空气燃烧或富氧燃烧解决其难以点燃和燃尽的问题,采用多种脱硫技术相结合的方式来处理石油焦应用于玻璃熔窑所产生的硫氧化物,同时指出玻璃企业采用石油焦替油不能一拥而上,应根据石油焦资源分布、供应来决定是否进行玻璃熔窑替油改造。     

循环流化床中石油焦与煤混合燃烧NO排放特性

在一座0．5MWt循环流化床热态试验台上进行了石油焦与煤混合燃烧试验，研究了烟气中NO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，如一次风率、过量空气系数、床温和Ca／S比等对烟气中NO排放浓度的影响规律进行了研究。试验表明对纯焦而言，其NO排放浓度较其他混合燃料要高得多，当燃料中焦煤比增大时，NO的排放浓度降低，对不同焦煤比的燃料，随一次风率增大，NO的排放量增加；随过量空气系数的增大，NO的排放浓度增大；随着运行床温的提高，NO排放浓度升高。     

Ignition of droplets of coal–water–oil mixtures based on coke and semicoke

To permit expansion of the resource base and utilize industrial waste, coal–water–oil fuels may be prepared on the basis of coke and semicoke, as well as common petroleum derivatives (fuel oil and spent compressor, turbine, and transformer oils). The minimal oxidant temperature corresponding to stable ignition of coal–water–oil slurries is established. Typical variation in fuel temperature in the course of reaction is determined, as well as the delay time of ignition and the total combustion time for individual droplets of such fuel suspensions. For droplets of initial size 0.5–1.5 mm, the influence of the various factors (droplet size, oxidant temperature, and concentration of the components) on the threshold (minimum) temperature and inertia of ignition is studied. It is shown that stable ignition of coke and semicoke in such fuel is possible at moderate oxidant temperatures: 700–1000 K.     

浮法玻璃窑炉石油焦粉全富氧燃烧探讨分析

以石油焦粉取代重油或天然气作为玻璃生产的燃料,降低成本的同时也会带来一系列问题,从而提出石油焦粉全富氧燃烧思路,取消蓄热室和小炉,并对浮法玻璃窑炉石油焦粉全富氧燃烧进行理论与经济效益分析,认为浮法玻璃窑炉石油焦粉全富氧燃烧技术是可行的。     

Petrology and minor element chemistry of combustion by-products from the co-combustion of coal,tire-derived fuel,and petroleum coke at a western Kentucky cyclone-fired unit

A western Kentucky power plant conducted a series of test burns with coal+tire-derived fuel (tdf) and coal+tire-derived fuel+petroleum coke blends. Collections of fuel, fly ash, and bottom ash/slag were made from the cyclone-fired unit under four fuel combinations: coal, coal+ca. 1% tdf, coal+ca. 3% tdf, and coal+ca. 3% tdf+petroleum coke. Fly ash carbons derived from the three fuel types can be distinguished, allowing an assessment of the impact of co-combustion on fly ash quality. While certain aspects of the ash chemistry are distinctive, Zn increasing in tdf-derived fly ash and Ni and V increasing in petroleum coke-derived fly ash, changes in the coal source between sampling dates complicate the assessment of the chemistry.     

Chemical-looping with oxygen uncoupling using CuO/ZrO2 with petroleum coke

Oxygen carrier particles of CuO/ZrO₂ were reacted with petroleum coke using chemical-looping with oxygen uncoupling (CLOU). The fuel was burnt in gas-phase oxygen released from the oxygen carrier particles during the fuel oxidation. The particles were then regenerated in 5-21% oxygen. In this process, the carbon dioxide from the combustion is inherently separated from the rest of the flue gases without the need for an energy intensive air separation unit. Copper oxide has thermodynamic characteristics that make it suitable as an oxygen carrier in CLOU. Particles were prepared by freeze granulation and were exposed cyclically with petroleum coke and oxygen in a laboratory fluidized bed reactor of quartz. The reaction temperature and oxygen concentration during the oxidation were varied. The average conversion rate of petroleum coke was a function of temperature and varied between 0.5%/s and 5%/s in the set-point temperature interval 885-985 °C. The conversion rate is considerably higher than rates obtained with the same fuel using iron-based oxygen-carrier in chemical-looping combustion. As for the regeneration with oxygen, the reduced particles reacted at low oxygen concentrations, with a considerable part of the reaction occurring near the thermodynamic equilibrium.     

浮法玻璃熔窑火焰空间石油焦部分替代重油燃烧的数值模拟

针对浮法玻璃熔窑火焰空间建立模型并进行了数值模拟,在保证热值相同的前提下,对比研究了重油燃烧及将石油焦部分替代重油燃烧时的流场分布特征。结果表明,石油焦部分代替重油燃烧后,两种燃料可很好地混合燃烧,窑炉内温度制度基本不受影响;石油焦着火时间比重油长,两种燃料混合燃烧时平均着火点滞后于仅使用重油时,且燃烧路径更长,燃烧时产生了大量CO,整个火焰空间及烟气出口处NOx的平均排放量与仅使用重油相比降低了30.02%,NOx减排效果明显。     

替代石油燃料和原料的可行技术及经济性分析

本文阐述利用洁净煤、高硫焦和天然气替代和节约石油燃料和原料的各种技术方案，并分别对其经济性进行了初步分析。展望以煤和天然气为原料替代石油、发展合成油的前景。     

Thermogravimetric study of coal and petroleum coke for co-gasification

As a preliminary study of gasification of coal and petroleum coke mixtures, thermogravimetric analyses were performed at various temperatures (1,100, 1,200, 1,300, and 1,400 °C) and the isothermal kinetics were analyzed and compared. The activation energies of coal, petroleum coke and coal/petroleum coke mixture were calculated by using both a shrinking core model and a modified volumetric model. The results showed that the activation energies for the anthracite and petroleum coke used in this study were 9.56 and 11.92 kcal/mol and reaction times were 15.8 and 27.0 min. In the case of mixed fuel, however, the activation energy (6.97 kcal/mol) and reaction time (17.0 min) were lower than the average value of the individual fuels, confirming that a synergistic effect was observed in the coprocessing of coal and petroleum coke. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

石油焦的燃烧特性

引　言高硫石油焦作为石化行业所生产的副产品 ,其含碳量高、含灰量少 ,具有较高的热值 ,用其作为一种替代燃料来发电、供热 ,不仅可以缓解我国能源短缺的矛盾 ,而且可以变废为宝 .近年来在世界上 ,越来越多的热电厂开始用石油焦特别是用含硫高的石油焦作为循环流化床燃烧锅炉的燃料来生产蒸汽发电或供热[1] .然而 ,石油焦作为一种替代燃料 ,其燃烧特性及其燃烧后所排放污染物 ,到目前为止 ,对其研究较少 ,而且均为实验室小台架试验[2～ 5] .关于热态试验尚未见报道 .循环流化床燃烧技术是一种清洁燃烧技术[6] ,它通过飞灰循环燃烧、控制床…     

Regimes of the Combustion of Organic Coal–Water Fuels

The results of an analysis of the combustion behavior of the drops of organic coal–water fuels (OCWFs) prepared based on the flotation products (cakes) of the enrichment the coal of five grades (longflame, gas, coking, low-caking, and lean coals) and two petroleum products (petroleum residue and spent turbine oil) are presented. The experiments were performed under the conditions of the stationary fastening of an OCWF drop on the junction of a quick-response thermocouple in a flow of heated (from 500 to 1000°C) air. The following three combustion regimes were revealed for all of the test OCWF compositions: stepwise regime with slow heating (smoldering), intense gas generation regime with the boiling of liquid fuel components (boiling), and regime with a distinct tear-off zone of gas flow (torch). It was shown that the occurrence of the above combustion behaviors substantially depends on the characteristics of the OCWF components: the ash content and the yield of volatile substances of coal cakes and the boiling points and the ignition and combustion temperatures of the petroleum products used. Based on the results of the experiments, the ranges of air temperature changes characteristic of each of the three combustion regimes of fuel suspensions were established.     

油泥焦与褐煤共燃特性及动力学

采用热重分析法研究了不同升温速率下油泥焦、褐煤及其混合物燃烧特性,并利用Kissinger-Akahira-Sunose（KAS）、Flynn-Wall-Ozawa（FWO）和Friedma（FR）等方法计算其燃烧动力学参数。结果表明,油泥焦燃烧主要是固定碳燃烧过程,而褐煤燃烧是挥发分和少量固定碳连续燃烧的过程。褐煤比油泥焦具有更好的燃烧特性,平均活化能更低。油泥焦和褐煤共燃过程中存在明显的协同促进作用,当混合燃料中褐煤占比为75%时协同促进效应达到最强。通过比较KAS、FWO和FR的结果发现,FR法能够更好地体现反应变化的趋势,而KAS法和FWO法的结果具有较高的准确性。通过比较油泥焦和褐煤共燃动力学参数的理论计算值与实验计算值发现,利用热重分析预测混合燃料的燃烧性质具有较高的可靠性,对油泥焦与褐煤共燃技术的应用具有重要的指导作用。     

Petroleum coke conversion behavior in catalyst-assisted chemical looping combustion

Efficiently using petroleum coke as fuel and reducing carbon emission meanwhile have become attractive in oil processing industry. The paper is focused on the application of Chemical Looping Combustion (CLC) with petroleum coke, with the purpose of investigating its combustion performance and effects of potassium. Some experiments were performed in a laboratory scale fluidized bed facility with a natural manganese-based oxygen carrier. Experimental results indicated that the coke conversion is very sensitive to reaction temperature. The present natural manganese-based oxygen carrier decorated by K has little effect on the improvement of coke conversion. XRD, SEM–EDX, and H₂-TPR were adopted to characterize the reacted oxygen carrier samples. After being decorated by K, the oxygen carrier's capacity of transferring oxygen was decreased. A calcination temperature above the melting point of K₂CO₃ (891 °C) shows better oxygen transfer reactivity in comparison to the one calcined at a lower temperature. The natural oxygen carrier used in the work has a high content of Si, which can easily react with K to form K(FeSi₂O₆). Further, irrespective of reaction temperature, the coke conversion can be significantly enhanced by decorating the coke with K, with a demonstration of remarkably shorter reaction time, faster average coke gasification rate and higher average carbon conversion rate.     

Devolatilisation behaviour of petroleum coke under pulverised fuel combustion conditions

The combustion of petroleum coke in large scale facilities has been limited due to its high sulphur content, but the increasing installation of flue-gas desulphurisation units makes possible the firing of petroleum coke either as a primary fuel or blended with coals. This study focuses on the behaviour of three fuel-grade petroleum cokes of different provenance under pulverised fuel combustion conditions. These cokes, ground and sieved 125–20 μm were fed to a drop tube reactor operating at 1300 °C under different atmospheres to produce chars with different combustion degrees. Char reactivity assessment was performed isothermally in a thermobalance at 550 °C and morphology and optical texture of the chars were studied by optical and scanning electron microscopy. Petroleum coke chars are composed of two main types of particles: (i) porous anisotropic particles that passed through a plastic stage and generated either cenospheric or network-like chars and (ii) angular particles with fine-mosaic optical texture that did not swell and show abundant contraction cleats. The relative proportions of both types of particles were very different in the three petroleum coke chars indicating significant differences in their devolatilisation patterns. The morphology and optical texture of the petroleum coke chars were related to their reactivity (as measured in a thermobalance) and to the characteristics (chemical composition and optical texture) of the parent petroleum cokes, in an attempt to understand the implications of their different devolatilisation behaviours on the combustion efficiency.     

煤中掺配高硫石油焦的气化特性研究

利用同步热分析仪对高硫石油焦(JL焦)、淮北煤(LY煤)以及淮北煤中掺配不同比例的JL焦混样在常压条件下进行CO2气化研究,并对气化动力学进行了分析。研究表明,JL焦的气化反应活性远远低于LY煤,配入LY煤能够提高JL焦的气化反应性,降低活化能;1 150℃之前,转化率的实验值低于加权平均值,且与掺焦比例没有关系;1 150℃之后,转化率的实验值高于加权平均值,原因是LY煤灰中的矿物质对焦、煤混样的气化起到了催化作用。     

Petroleum coke conversion behavior in catalyst-assisted chemical looping combustion

Efficiently using petroleum coke as fuel and reducing carbon emission meanwhile have become attractive in oil processing industry. The paper is focused on the application of Chemical Looping Combustion (CLC) with petroleum coke, with the purpose of investigating its combustion performance and effects of potassium. Some experiments were performed in a laboratory scale fluidized bed facility with a natural manganese-based oxygen carrier. Experimental results indicated that the coke conversion is very sensitive to reaction temperature. The present natural manganese-based oxygen carrier decorated by K has little effect on the improvement of coke conversion. XRD, SEM-EDX, and H₂-TPR were adopted to characterize the reacted oxygen carrier samples. After being decorated by K, the oxygen carrier's capacity of transferring oxygen was decreased. A calcination temperature above the melting point of K₂CO₃ (891 °C) shows better oxygen transfer reactivity in comparison to the one calcined at a lower temperature. The natural oxygen carrier used in the work has a high content of Si, which can easily react with K to form K(FeSi₂O₆). Further, irrespective of reaction temperature, the coke conversion can be significantly enhanced by decorating the coke with K, with a demonstration of remarkably shorter reaction time, faster average coke gasification rate and higher average carbon conversion rate.