Numerical Simulation and Assessment of a Two‐Stage Gasifier Modified from an Opposed Multi‐Burner Gasifier

An opposed multi‐burner (OMB) entrained‐flow gasifier with coal water slurry feeding is developed by the East China University of Science and Technology. A 3D model is employed to numerically simulate the gas flow field, motion of char particles, and distributions of temperature and gaseous components in an OMB gasifier and in a conceptual two‐stage gasifier modified from the OMB gasifier (TS‐OMB gasifier). Results show that the TS‐OMB gasifier produces higher concentration and productivity of the effective gases (CO+H₂) with a slightly higher carbon conversion than the OMB gasifier. The reasons for the differences between these two types of gasifier are discussed by means of numerical simulation. This information is valuable for guiding the design of an advanced OMB gasifier.     

Effects of burner type on a bench-scale entrained flow gasifier and conceptual modeling of the system with Aspen Plus

The integrated gasification combined cycle (IGCC) system is well known for its high efficiency compared with that of other coal fueled power generating systems. In this study, gasification using different types of burners with different oxygen supply angles in a bench-scale entrained flow gasifier was investigated. The effects of the oxygen gas supply angle of the coal burner and resulting oxygen supply location in the gasifier on the syngas composition and temperature of the gasifier were experimentally examined. These changes had a significant influence on the syngas composition of the final stream, carbon conversion, and efficiencies. According to the experimental results, the models using the Aspen Plus process simulator were positioned to define the effects of the experimental parameters and to find the optimum operating conditions in the bench gasifier facility.     

多喷嘴对置式水煤浆气化炉内火焰声学特性分析

气化炉内火焰声学信号是表征水煤浆气化炉内火焰燃烧及流动特性的重要信息。为了更好地了解气流床气化炉内撞击火焰的燃烧特性及其对气化炉的影响,在多喷嘴对置式气流床气化炉中,进行了两喷嘴撞击火焰和四喷嘴撞击火焰的变工况试验。应用统计理论和Hilbert-Huang变换对炉内火焰声学信号分别进行了时域和频域的分析。结果表明,随着燃料或氧气的增大,火焰化学反应速率加快,燃烧越来越剧烈,火焰的稳定性越来越差,其中氧气对火焰的影响大于燃料。四喷嘴工况的撞击火焰噪声的标准偏差值要大于两喷嘴,但标准偏差随工况的变化小于两喷嘴,说明四喷嘴撞击火焰燃烧剧烈但稳定。低氧燃比工况时,四喷嘴能量和频率的分布主要集中在45 Hz以下的低频段和45～100 Hz的中频段,比两喷嘴工况更集中于低频段。     

多通道烧嘴水煤浆气化过程数值模拟

针对气化炉烧嘴在使用过程中出现的雾化效果差的问题,采用了DPM颗粒离散多相流模型,研究了同心三通道烧嘴使用过程中的水煤浆管内流动和雾化规律。改变多个影响因素并正交分析后得出:水煤浆雾化受烧嘴内外两气道气体流速变化的影响,气体流速增大时,水煤浆SMD值降低;当增加水煤浆流道锥角,使水煤浆与气体射流充分预混时,SMD值减小明显。此外,增加烧嘴出口节流同样会减小SMD值。综合比较各因素的影响,发现节流尺寸和内喷嘴气体流速对水煤浆的雾化效果影响最大。     

Experimental study on CH* chemiluminescence characteristics of impinging flames in an opposed multi‐burner gasifier

The bandpass filtered images of impinging flames in an opposed multi‐burner (OMB) gasifier was visualized by a CCD camera combined with a high temperature endoscope. A filtering and image processing method by use of three bandpass filters was applied to subtract soot and CO₂* contributions in the CH* band and obtain the CH* chemiluminescence of impinging flames. The results show that a clear reaction core is generated in the impinging zone of four‐burner impinging flames. The size of the reaction core is affected by the O/C equivalence ratio ([O/C]_e) and the impingement effect is relatively stronger at lower [O/C]_e. The flame lift‐off length in the gasifier is jointly controlled by the syngas concentration and the diesel atomization effect. The impingement effect shortens the flame lift‐off length. The relationship between the syngas concentration and the maximum CH* intensity makes it possible to evaluate the syngas concentration from CH* intensity. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2007–2018, 2017     

加压气流床煤气化工艺的发展现状及存在问题

介绍了国内外开发的主要加压气流床煤气化工艺的发展现状,包括德士古气化、E-Gas气化、壳牌和普兰福气化、GSP气化、多喷嘴水煤浆加压气流床气化、两段喷干煤粉的气流床加压气化等,列举出这些气化技术中目前存在的主要问题,并对其解决途径进行了探讨,提出了一些建议。     

基于Aspen Plus建立喷流床煤气化炉模型

引　言当前 ,环境污染和液体燃料短缺已经成为制约我国经济持续高速和安全发展的瓶颈问题 .通过煤的大规模、综合、清洁、高效利用来解决未来对能源尤其是对液体燃料的需求 ,已经成为我国政府和科学界的共识[1] .在未来的能源结构中 ,以煤气化为基础的新型能源系统无疑将扮演越来越重要的角色[2 ] .因此 ,深入开展以煤气化为基础的新型能源系统尤其是多联产系统的研究十分必要 .鉴于煤气化能源系统中涉及大量横跨动力过程和化工过程的特殊设备 ,本文选择Aspen作为工具软件开展研究 ,其中的一个重要任务就是建立能在Aspen中使用的特殊设备模…     

应用炉膛压力诊断气流床气化炉的火焰状态

气化炉是煤气化技术中的关键设备 .气化炉内火焰燃烧稳定性下降 ,会出现燃烧噪音增加、气化燃烧效率降低及熄火等现象 ,对安全性和经济性产生严重的影响 .对气流床气化炉内不同气化燃烧状态下的火焰压力信号进行了小波分析 .结果表明 ,压力信号在一定频段内的分布与气化炉内火焰燃烧的状态密切相关 ,发现随着火焰燃烧稳定性加强 ,气化炉内压力信号向高频方向移动 ,以此可以建立气流床气化炉燃烧诊断模型 .     

盈德清华炉水煤浆气化工艺的影响因素研究

以过程模拟软件为工具,通过合理的简化与假设,建立了以氧气为气化剂的水煤浆气流床煤气化的研究模型,模拟计算了盈德清华炉的水煤浆气化过程,分析了煤中碳含量、灰分含量、水煤浆质量分数、操作温度、水冷壁副产蒸汽量等因素对比煤耗、比氧耗、合成气产量、合成气中各气体组分含量的影响。模型计算结果与生产实际运行数据对比表明,该模型能较好地反映运行工厂的实际生产情况。利用经过生产实际运行数据修正的研究模型,可研究煤质组成、煤浆质量分数、操作温度、水冷壁副产蒸汽量等因素对主要气化工艺指标的影响。     

Entrained‐flow gasifier fuel blending studies at pilot scale

For the foreseeable future, coal and petroleum‐based materials, such as petroleum Coke, residuals, and high‐sulphur fuel oil, are being adopted as the feedstocks of choice for gasification projects. Of particular interest from a Canadian perspective is Coke generated from the thermal cracking of the oil sands in Western Canada. Oil sand Coke contains high sulphur (5–6%), and also typically has a low volatile content, and lower reactivity than most coals. Experimental runs have recently been conducted on the pilot‐scale entrained‐flow gasifier at CETC‐Ottawa, blending oil sand Coke with sub‐bituminous and lignite coals, to try and enhance the gasification potential of these materials. Blending Genesee sub‐bituminous coal with the delayed oil sands Coke was found to alleviate problems encountered with slag plugging the reactor when running with Genesee coal alone. Blends of Genesee sub‐bituminous and Boundary Dam lignite coals with Coke achieved higher carbon conversions and cold gas efficiencies than runs completed with the Coke by itself. While using CO₂ as the conveying gas into the gasifier was not found to significantly affect the conversion obtained, steam addition was found to have a marked effect on CO and H₂ concentrations in the syngas.     

二次氧量对分级气化炉气化特性的影响

分级给氧气流床气化炉具有碳转化率高、炉内混合过程强烈、喷嘴附近温度较低等优点。本文采用CFD数值模拟的方法研究了二次氧量变化对气化炉运行特性的影响,分析比较了不同二次给氧量下相交射流火焰特性的变化,及相交射流对煤气化炉炉内整体混合过程、煤气化特性的影响。发现当二次给氧量下降时,受炉内回流流场的影响,二次火焰明显随回流发生偏斜,壁面温度升高。当二次给氧量小于总给氧量的8%时,其射流动量不足以影响主射流产生的宏观流场。     

运用Gibbs自由能最小化方法模拟气流床煤气化炉

基于 Aspen Plus工业系统流程模拟软件 ,运用 Gibbs自由能最小化方法建立了气流床煤气化炉的模型 .研究了气化炉的主要操作参数 (即水煤浆浓度、氧煤比、碳转化率和气化温度 )对气化结果的影响 .对模拟结果进行了分析 ,发现模型基本正确 ,可应用于一些反应机理复杂的气化工艺的化学和热力学平衡计算 .模拟结果表明 ,氧煤比和水煤浆浓度是影响气化炉出口煤气组成的主要因素 ,气化炉温度随着氧煤比的增加而增加 ,也随着水煤浆浓度的增加而增加 .结果还表明 ,氧煤比对气化结果的影响比水煤浆浓度的影响更为显著     

A new integrated approach of coal gasification: the concept and preliminary experimental results

The total carbon conversion of conventional fluidized bed gasifier is relatively low (<90%) mainly because of carbon loss in fly-ash. In this paper, a new concept of integrated coal gasification—fluidized bed+entrained flow is introduced. Within this process, large partition of coal with higher reactivity is converted in an ash agglomerating fluidized bed reactor under moderate temperature (~1000 °C). The remaining small partition of coal (fly-ash) with lower reactivity is converted in a small integrated entrained flow gasifier under higher temperature (1200–1400 °C). Low carbon content ash is withdrawn in dry mode by ash agglomerating, with no need to be melted. Preliminary experimental results show that the whole system can be operated steadily, total carbon conversion reaches >95%, efficient gas (CO+H₂) concentration is 78–82%. Heat exchange between two reactors has been realized, the high temperature gas from entrained flow gasifier can be cooled, and in the mean time the temperature of fluidized bed nearly keeps constant. The high-temperature ash from entrained flow gasifier can be cooled by the char in dense phase of the fluidized bed and then withdrawn in agglomerating mode. All these results prove the concept correct and feasible.     

水煤浆加压气化技术改造小结

自1994年3月10日德士古水煤浆加压气化装置通过生产考核以来，根据实际情况对不适应系统稳定生产的文氏洗涤器，气化炉上升管支撑，闪蒸系统管道及气化炉渣口予以改造，并对气化炉耐火材料，气化炉烧嘴和高，低压煤浆泵实施了国产化措施，取得显著成效，标志着我厂驾驶水煤浆加压气化装置的能力已达到了较高水平。     

Development of a hybrid shrinking‐core shrinking‐particle model for entrained‐flow gasifiers

Slagging entrained‐flow gasifiers operate above the melting temperature of the ash. As slag is highly nonwetting on the surface of char (carbon) particles, it is likely that it will agglomerate into one or several slag droplets and some of these droplets can detach from the char particles. If the slag exists in the form of droplets on the char surface rather than as a solid shell around the unreacted char particle, a shrinking particle model would be more physically realistic representation in comparison to the widely used shrinking core model (SCM). In the early section of the gasifier, the temperature remains below the ash melting temperature and, therefore, the SCM is more appropriate in this region. With this motivation, a novel hybrid shrinking‐core shrinking‐particle model has been developed. The model provides spatial profile of a number of important variables that are not available from the traditional SCM. © 2015 American Institute of Chemical Engineers AIChE J, 62: 659–669, 2016     

Numerical modelling and simulation of pulverized solid‐fuel combustion in swirl burners

A finite‐volume numerical model for computer simulation of pulverized solid‐fuel combustion in furnaces with axisymmetric‐geometry swirl burner is presented. The simulation model is based on the k ? ε single phase turbulence model, considering the presence of the dispersed solid phase via additional source terms in the gas phase equations. The dispersed phase is treated by the particle source in cell (PSIC) method. Solid fuel particle devolatilization, homogenous and heterogeneous chemical reaction processes are modelled via a global combustion model. The radiative heat transfer equation is also resolved using the finite volume method. The numerical simulation code is validated by comparing computational and experimental results of pulverized coal in an experimental furnace equipped with a swirl burner. It is shown that the developed numerical code can successfully predict the flow field and flame structure including swirl effects and can therefore be used for the design and optimization of pulverized solid‐fuel swirl burners.     

干煤粉加压气化技术的现状和进展

干法进料的气流床煤气化技术是当今国际上最先进的煤气化技术之一,与水煤浆气化技术相比,具有煤种适应性广、原料消耗低、碳转化率高、冷煤气效率高等优势,有更强的市场竞争力。为了加强对干煤粉加压气化技术的基础研究和应用推广,研究了干煤粉气化炉、气流输送过程、合成气净化系统及其配套工艺,分析了干煤粉气化炉在应用中存在的问题,并针对这些问题提出了解决的思路。概述了国内外大型粉煤气流床气化技术发展的主要情况,分析了干法进料气流床煤气化技术中存在的问题与采取的技术途径。     

新型气流床气化炉的概念性设计

新型气流床气化炉综合了现有干湿法气流床气化炉的优点,分段设计理念,采用湿法进料和干法气化原理,特殊的激冷器结构,喷嘴设计采用空间多通道设计,煤浆和氧气喷嘴均为单通道结构且单独进料,拉长了着火点与喷嘴头部距离,气化指标好,生产能力大。     

水煤浆加压气化主要技术与装备进展

简述了国内工业化应用较多的4种水煤浆加压气化技术,介绍了水煤浆加压气化技术的关键设备,通过对水煤浆加压气化技术中工艺烧嘴、气化炉耐火衬里、自动控制系统等关键技术装备的研究,影响装置长期稳定运行的一些瓶颈问题将逐步得到解决。     

射流携带床气化炉内宏观混合过程研究(Ⅲ)过程分析与模拟

对射流携带床气化过程进行了分析,提出了气化过程的机理模型;建立了射流携带床气化炉的数学模型,对工业操作条件下的渣油和水煤浆气化炉进行了模拟,预测了工艺条件对气化结果的影响。