Effect of slag composition on corrosion resistance of high chromia refractory bricks for industrial entrained-flow gasifier

The slag composition corresponding to different coals varies significantly,which directly affects the operation of industrial entrained-flow gasifier and the service life of refractory bricks.In this study,the corrosion resistance of several typical coal slags for gasification on high chromia refractory bricks was comparatively investigated by static laboratory crucible tests and thermodynamic simulations.The results demonstrated that the corrosion degree of high chromia refractory bricks by different coal slags was high-Ca/Na slag>high-Fe slag>high-Si/Al slag.The surface structure of the refractory was relatively flat after corrosion by high-Si/Al slag,and the primary corrosion reaction was the partial dissolution of the matrix by the slag.High-Fe slag was prone to the precipitation of iron phases as well as the formation of(Mg,Fe)(Al,Cr)_(2)O_(4)composite spinel layer at the slag/refractory interface.The high-Ca/Na slag was susceptible to react with the refractory to yield a low melting point phase,which led to the destruction of the matrix structure of the refractory and an isolated distribution of particles.In addition,the monoclinic ZrO_(2) in the refractory reacted with CaO in the slag to formed calcium zirconate,which loosened its phase toughening effect,was the primary factor that aggravated the refractory corrosion.

Comparison of Combustion Characteristics of Tars Produced with Tobacco Stem Biomass Gasification

In order to study the combustion characteristics of tar in biomass gasifier inner wall and gasification gas,“tobacco stem semi-tar inside furnace”,“tobacco stem tar inside furnace”and“tobacco stem tar out-of-furnace”were subjected to thermogravimetric experiments,and the combustion characteristics and kinetic characteristics were analyzed.The result shows that“tobacco stem semi-tar inside furnace”has the highest value and“tobacco stem tar out-of-furnace”is has the lowest value on ignition characteristics,combustion characteristics and combustible stability;“tobacco stem semi-tar inside furnace”has the lowest value and“tobacco stem tar outside furnace”has the highest value on burnout characteristics;“tobacco stem tar outside furnace”has the highest value and“tobacco stem tar inside furnace”has the lowest value on integrated combustion characteristics.

U-GAS气化炉高碳飞灰燃烧特性

采用热天平研究了U-GAS气化炉高碳飞灰燃烧特性,考察了灰分以及不同升温速率对飞灰燃烧特性的影响,探讨了飞灰造粒后应用于流化床锅炉燃烧的可行性.结果表明:与入炉煤粉相比,飞灰着火温度高、燃尽时间长、反应性较差;飞灰中灰分对飞灰燃烧性能和反应性能产生不利影响;随着升温速率增大,飞灰着火温度及燃尽温度升高,燃尽时间缩短,反应性增强;造粒后飞灰颗粒着火温度、燃尽温度均与煤粉接近,且它们的燃烧温度区域基本重合,颗粒可用于流化床锅炉燃烧.

Fe_3Al金属滤芯特性及在U-gas煤气化装置中的应用

为了解决U-gas粉煤气化工艺飞灰过滤器装置中陶瓷滤芯的断裂问题,分析了陶瓷滤芯和金属滤芯的性能差异,在装置中安装了国产改进2050型Fe_3Al金属滤芯并投运试验,研究了投运后合成气及飞灰特性、滤芯的微观形貌、过滤效率、流量-压差曲线、滤饼渗透性等特性。结果表明,在与陶瓷滤芯相同过滤精度条件下,Fe_3Al金属滤芯具有孔隙率高、渗透性高、压溃强度大等优势。投运结果表明,Fe_3Al滤芯投运3个月以来无断裂故障,在相近工况条件下,Fe_3Al滤芯运行平衡压差相比陶瓷滤芯下降了50%,且水洗塔悬浮物固含量由1 000~2 000 mg/L下降至100~500 mg/L。

U-GAS气化炉加煤系统故障分析与处理

对U-GAS气化炉在劣质煤转化过程中其加煤系统易出现的故障进行了深入分析和研究,提出了相应的改造方案;对充压、泄压系统管路,有关控制程序及阀门等进行改造后,取得了较好的效果。

U-GAS粉煤流化床煤气化废水设计及运行实例

针对某化工厂排放的U-GAS粉煤流化床煤气化废水成分复杂、有机物浓度高的特点,采用了预处理-IMC生化处理-臭氧氧化-曝气生物滤池组合工艺。给出了主要构筑物及设计参数,阐述了工程设计技术特点。该工程运行结果表明,在进水CODCr、BOD5、NH3-N的质量浓度分别为500、280、180 mg/L的条件下,出水水质可稳定达到GB 8978—1996《污水综合排放标准》一级标准的要求。

CFD simulation on the gasification of asphalt water slurry in an entrained flow gasifier

Gasification technology is suggested to utilize asphalt particles, which are produced in the heavy oil deep separation process of using coupled low temperature separation of solvent and post extraction residue. In this work, the asphalt particles were first slurried with water and then gasified to produce synthesis gas. The gasification process of asphalt water slurry in an entrained flow gasifier was simulated using a three-dimensional computational fluid dynamics （CFD） model based on an Eulerian- Lagrangian method. The trajectories and residence time of asphalt particles, and the reaction rates, gas species distribution, temperature field and carbon conversion in the entrained flow gasifier were obtained. The predicted results indicated that the asphalt water slurry was a good feedstock for gasification. Moreover, the effects of particle size, oxygen equivalence ratio, and mass content of asphalt particles on the gasification performance of asphalt water slurry were investigated. These results are helpful for industrial application of asphalt water slurry gasification technology.

Assessment of coal gasification in a pressurized fixed bed gasifier using an ASPEN plus and Euler–Euler model

With the help of Aspen Plus,a two-dimensional unsteady CFD model is developed to simulate the coal gasification process in a fixed bed gasifier.A developed and validated two dimensional CFD model for coal gasification has been used to predict and assess the viability of the syngas generation from coal gasification employing the updraft fixed bed gasifier.The process rate model and the sub-model of gas generation are determined.The particle size variation and char burning during gasification are also taken into account.In order to verify the model and increase the understanding of gasification characteristics,a set of experiments and numerical comparisons have been carried out.The simulated results in the bed are used to predict the composition of syngas and the conversion of carbon.The model proposed in this paper is a promising tool for simulating the coal gasification process in a fixed bed gasifier.

Damage Mechanism of High Chrome Bricks for Opposed Multi Nozzle Gasifier and Their Improvement

To reveal the damage mechanism of high chrome bricks for opposed multi nozzle gasifier with expanded diameter,the chemical composition and the morphology of a used high chrome brick were researched using XRF,SEM and EDS,and the properties of the high chrome bricks were improved by adding ultra fine alumina,alumina-chrome-iron oxide synthetic material with spinel structure,and chromium metal.The results show that(1)the high chrome brick is seriously damaged by the chemical dissolution of chrome as well as the chemical reactions at the slag/brick interface,the slag penetration and the structural spalling;(2)FeO in the slag reacts with Cr_(2)O_(3)in the brick to form a FeCr_(2)O_(4)layer on the particle surface thus leading to spalling;CaO reacts with SiO_(2)and Al2O3 in the brick forming a metamorphic layer of low melting point materials;due to the different thermal expansion coefficients of the metamorphic layer and the original brick,cracks appear and continue to expand and deepen under multiple temperature and pressure fluctuations thus leading to spalling of brick layer;(3)the improved brick has decreased apparent porosity,increased bulk density and compressive strength,and better thermal shock resistance compared with the original brick;after one cycle of on-site application,the furnace lining surface is smooth and flat with little damage,indicating that the improved high chrome bricks basically meet the working condition requirements of the opposed multi nozzle gasifier with expanded diameter,however,the final effects need to be evaluated in detail after the whole furnace service.

Variation of toxic pollutants emission during a feeding cycle from an updraft fixed bed gasifier for disposing rural solid waste

The variation of toxic pollutants emission during a feeding cycle was examined by field monitoring from a batch feeding updraft fixed bed gasifier for disposing rural domestic solid waste. Results showed that the content of oxygen in flue gas gradually increased, while SO_2 and HCl in flue gas decreased with time after feeding in a whole feeding cycle. Although large amount of CO was produced during the gasifying, low CO content in flue gas could be obtained after the heat treatment with an electric heating device. The distribution characteristics of dioxin congeners in flue gas indicted the re-synthesis of dioxins after flue gas heating, and the increase of oxygen promoted the synthesis of dioxins. The emission content of dioxins could meet the standard(0.1 ng I-TEQ·m^(-3),GB18458-2014) of China when the oxygen content was controlled below 8.3%. Hence, for a batch feeding gasifier,low oxygen condition should be offered by reducing air intake at the later stage of feeding cycle in order to decrease the re-synthesis of dioxins after the flue gas heating.

关于U-GAS煤气化生产合成氨的探讨

针对Ｕ－ ＧＡＳ 煤气化技术的特性和第一套商业性工业化装置要点， 以实例分析了采用Ｕ－ ＧＡＳ 烟煤气化生产合成氨精原料气在技术和经济两方面的可行性， 同时以实例论述了Ｕ－ ＧＡＳ 煤气化技术在节能、降本、环保诸方面的综合效果， 并就技术改造中所联想的主要问题进行了分析。

新型煤矸石多联供U-Gas气化炉的技术特性

国内的煤矸石处理技术已呈现多元化的发展趋势,然而部分热值较高的煤矸石目前还只是停留在焚烧产能上,但由于其具有的高硫、高灰的特点,焚烧过程中的污染现象不可避免。美国SES公司适时推出了煤矸石多联供气化技术,利用新型的U-Gas气化炉,通过煤矸石的气化,在提供化工原料的同时,供应电力和蒸汽,特别适合在原煤产地建设煤化工项目,并达到改善环境状况的目的。

陶瓷过滤器及金属滤芯在U-Gas气化装置中的应用

介绍了陶瓷除尘煤气净化系统的结构及工作原理,并讨论了其在U-Gas气化装置中的运行情况,运行结果证明,该系统过滤精度高、运行效果稳定、可靠。

U-GAS气化工艺配套空分方案分析

针对U-GAS气化炉操作压力下空分界区氧气和氮气的压力要求,可供选择的空分流程较多,选取了双泵-中压膨胀流程、单泵-中压膨胀流程、单泵-低压膨胀流程、外压缩流程以及自增压-外压缩流程5种空分方案进行对比。简述了空分部分的工艺流程,介绍了5种空分方案流程的异同,并对5种空分装置的运行能耗、投资、占地等进行了对比,为不同工艺流程的配套最优空分方案选择提供了参考。

U-Gas气化炉飞灰返炉方案探讨

针对U-Gas气化工艺过程会产生大量含碳量较高的细粒飞灰,致使气化炉碳转化率低,分析气化飞灰产生的原因及返炉回用的意义,并对返粉具体位置的优缺点进行分析和比较。

关于U-Gas气化技术的认识

介绍了U-Gas气化技术的工艺流程,阐述了U-Gas气化炉的结构及U-Gas气化技术的独特优势,分析了控制煤气中CH4含量的手段。

U-GAS气化技术改造中小型氮肥企业固定层造气炉的研究

中小型氮肥企业造气工段大多采用常压固定层间歇气化工艺,存在原料成本和能耗高、污染严重等问题。采用U-GAS气化技术改造固定层造气炉,节能环保,可有效降低企业生产成本。结合河北某化肥企业"24·40"装置现有情况,以充分利用现有工艺流程和设备为原则,详细分析了造气工段改造后对其他各工段的影响,并对改造前后的能耗、生产成本进行对比。分析结果表明,采用U-GAS气化技术改造固定层造气炉,技术上可行,经济上合理,改造后吨氨成本可降低568元。

IA集散控制系统在U-Gas气化炉输煤装置中的应用

阐述U-Gas气化炉的输煤系统,基于Foxboro IA集散控制系统进行改造的设计方法和实现过程。通过对原输煤系统进行改造后,有效提高气化炉输煤单元的自动化水平,从而提高企业的经济效益。

Syngas cleaning with nano-structured micro-porous ion exchange polymers in biomass gasification using a novel downdraft gasifier

Sulphonated nano-structured micro-porous ion exchange polymers, known as sulphonated PolyHIPE Polymers （s-PHPs） were used in syngas cleaning to investigate their impact on tar composition, concentration and dew point depression during the gasification of fuel cane bagasse as a model biomass. The results showed that the s-PHPs used as a secondary syngas treatment system, was highly effective at adsorbing and reducing the concentration of all class of tars in syngas by 95%-80% which resulted in tar dew point depression from 90 ~C to 73 ~C. It was shown that tars underwent chemical reactions within s-PHPs, indicating that tar diffusion from syngas was driven by chemical potential. It was also observed that s-PHPs also captured ash forming elements from syngas. The use of s-PHPs in gasification as well as in an integrated thermochemical biorefinery technology is discussed since the tar loaded s-PHPs can be used as natural herbicides in the form of soil additives to enhance the biomass growth and crop yield.

U-GAS气化炉高点放空废气排放系统优化

论文主要讲述河南能源义马煤业综能新能源有限责任公司使用的U-GAS气化炉在点火开工时,煤气中含有大量粉尘,采用高点放空直接排放会对环境造成严重污染。为满足环保要求,论文对气化炉点火开工高点放空废气的处理方法进行介绍,以期进行交流推广,为今后的施工提供借鉴。