双金属改性的Ni/SiO2催化剂甘油催化重整制合成气

使用不同的金属(Co、Cu、Sn)对甘油重整制合成气的Ni/SiO2催化剂进行了改性研究,在固定床反应器上考察了甘油的转化率和产物的H2与CO的体积比。结果表明,相较于使用单金属Ni的催化剂,Co的添加增强甘油重整的催化活性,450℃时甘油的气相转化率达78.6%,此时产物也以H2和CO为主,且V(H2)/V(CO)=1.94,较为接近F-T合成所需原料气的要求2;在450℃下,甘油进料体积流量为0.5 mL/min时,利于甘油转化为V(H2)/V(CO)接近2的合成气。     

关于Deckwer模型中某些参数的修正

一、前言F-T 合成是由煤制取合成燃料和化工原料的重要工艺。鉴于鼓泡浆态反应器适宜于慢反应和能使用富 CO 合成气的优点,液相 F-T 合成一般均采用鼓泡浆态反应器,为了合理设计和放大鼓泡浆态反应器,建立反应器数学摸型摸拟试验各种参数对反应器性能的影响是十分必要的。许多作者对 F—T 合成鼓泡浆态反应器提出了各自的数学摸型,其中以 Deck-wer 的扩散摸型较合理地描述了大型 F—T 合成鼓泡浆态反应器的行为。但是,Deckwer 在参数的选取方面不够严密。例如,Deckwer 假定反应实际消耗的CO/H_2的比等于原科气中的 CO/H_2比。由化学计量可知,这是得到最佳产率的理想条     

化学链重整制合成气过程模拟

基于化学链重整原理,以甲烷为原料,运用Aspen Plus对化学链重整制合成气系统进行了模拟,并研究了燃料反应器温度TF、水甲烷比W/M及NiO甲烷比Ni/M对重整气组成、合成气产率Y、系统效率η影响。结果表明,化学链重整气组成模拟值与实验值吻合较好。提高TF,重整气中CO、H2O含量有升高趋势,H2、CO2含量略微降低;随着W/M增加,重整气中H2、CO2含量升高,CO含量降低,合成气产率Y几乎不变,系统效率η呈现降低趋势;Ni/M增加,重整气中H2、CO含量以及合成气产率Y呈现先升高后降低趋势,效率η下降,且Ni/M=0.8时,合成气产率Y取得最大值。     

高速固定床F-T法合成液体燃料

本文在一般性介绍F-T合成各种床型的同时,将着重叙述高气速固定床反应器和过程参数对反应结果的影响,通过各种反应器床型特性的比较,说明高气速固定床采用尾气循环增加气速有利传热,提高了催化剂负荷,而相对冷却面仅是其余反应器的5～7％,在F-T合成液体燃料反应器中高气速固定床是成熟,可靠的反应器。     

浆态床FT合成技术的国内外发展概况

0前言 F-T合成是由煤制取合成燃料和化工原料的重要转化技术.到目前为止,已工业化的F-T合成技术有SaSo l正在运转的固定床(Arge反应器)、气流床(Synthol反应器)和固定流化床(FFB)技术.合成气(CO+H_2)以鼓泡方式向上通过含有粉状催化剂的液相惰性介质进行反应的浆态床F-T合成技术,始于1938年德国Kōlbel等的研究,并于50年代前期实现了日产11.5     

生物质合成气调变方式对其合成甲醇的影响

对生物质气、工业合成气、重整后生物质气及配氢后生物质气4种合成气进行了合成甲醇的研究. 发现甲醇产率顺序为工业合成气>重整生物质气>配氢生物质气>生物质气,生物质气合成甲醇产率较低主要是因为其为富CO2体系. 实验同时发现(H2-CO2)/(CO+CO2)比值在1.5~2之间时,(H2-CO2)/(CO+CO2)比值对液相产物中甲醇选择性没有明显影响. 液相产物中甲醇选择性随CO2含量上升而下降.     

尾气循环的费托反应固定床模拟及分析

费托合成的工业生产过程一般采用尾气循环操作以提高合成气的转化率。文章通过建立尾气循环的固定床二维非均相模型,对不同入口温度、压力、冷却水温度等操作情况进行了模拟计算;同时,详细分析了循环比、循环气和原料气组成等对反应过程CO转化率和热点温度等的影响。结果表明:在反应过程中的CH4等惰性气体体积分数对尾气循环操作下的CO转化率及反应器温度分布有显著影响。     

铁基化学链法调节合成气氢碳比及联产氢气的实验研究

利用固定床反应器考察了实验参数对调节用于费托合成的合成气中H2/CO及产氢的影响. 结果表明,500~800℃条件下,合成气(H2/CO为0.5)经过固定床反应器时,出口H2/CO可达0.87~0.53;通过在还原阶段通入适量水蒸汽,可有效提高调节H2/CO的能力,且能增加氧化阶段的产氢量. 此外,还原阶段加入水蒸汽还能有效抑制积碳生成,所制H2纯度接近100%. 在载氧体颗粒中加入石墨作为扩孔剂,可增强颗粒反应活性和稳定性,经过6个循环后,实际产氢量仍保持在理论产氢量的40%以上(不加石墨仅为20%)且仍保持一定的孔结构,而未加石墨的颗粒几乎完全烧结.     

Na2CO3-K2CO3熔盐法同时制取合成气和金属锌

针对传统的甲烷转化制合成气及金属锌制备技术的缺陷,提出了一种新型的熔融盐反应体系,在熔融盐反应器中以熔融盐(质量比为1:1的Na2CO3/K2CO3)为反应介质对CH4与ZnO反应同时生成金属锌和合成气作了实验研究,利用气相色谱对气体组分进行了分析. 结果表明,反应尾气组分主要是H2, CO和CH4,未检测到CO2,其中合成气的量及H2/CO比例随反应温度的升高而增加,在1198 K左右获得了H2/CO比为2的合成气. 合成气和金属锌分别从气相和熔融盐中获得. 用XRD, SEM及EDS对金属锌产品和熔融盐进行了表征,发现反应后的熔融盐含有少量Na2O和NaOH,来自于CH4与熔融盐之间的微弱反应,由此推断熔融盐还具有消碳功能.     

煤种对煤与天然气共气化过程的影响

以移动床为反应器,进行煤与天然气共气化热态模拟实验,对无烟煤、瘦煤、肥煤与焦炭进行了对比研究,考察了煤种在不同喷吹参数H2O/CH4/O2时对高温火焰区温度、合成气有效成分H2+CO和H2/CO、以及CH4与水蒸汽转化率的影响. 结果表明,相对于焦炭,煤为原料时,高温火焰区温度略高,粗合成气有效成分H2+CO体积含量较高,且H2/CO更接近于热力学平衡值. 通过不同煤种的实验,可以直接制备H2/CO在1~2之间可调、有效成分H2+CO体积含量大于92%、残留CH4小于2%的粗合成气,CH4转化率超过90%,水蒸汽转化率高达75%. 煤种中高灰分含量有利于煤与天然气共气化过程.     

基于Aspen模拟费托合成与CO_2再利用系统

建立了集成费托合成与碳还原反应系统的模型,采用Aspen软件进行仿真分析和计算,重点分析碳气化反应过程及费托合成的产物分布。在煤气化联合循环发电系统中集成该模块,CO2与焦炭发生还原反应得到CO,与来自煤气化单元的H2在费托合成反应器里合成液体燃料,未反应完的合成气用于燃气轮机联合循环发电。针对碳还原反应器和费托合成反应器两部分进行了模拟分析,研究了反应条件对产物的影响。分析结果表明回收CO2制取具有高附加值的液体燃料是CO2再利用的一条有效途径。     

使用Aspen Plus模拟煤与生物质共气化制费托油

使用流程模拟软件Aspen Plus,对煤与生物质裂解共气化合成气一次通过制费托油(FTL)和CO2收集和储存(CBTL-OT-CCS)过程进行物料衡算和模拟.通过对模拟的数据分析发现:生物质占原料比增加可以有效降低温室气体的排放;F-T反应器中催化剂的选择对产物分布有规律性的影响;探讨了CO2零排放的情况.     

Modeling and optimization of a large-scale slurry bubble column reactor for producing 10,000 bbl/day of Fischer-Tropsch liquid hydrocarbons

A user-friendly simulator based on a comprehensive computer model for slurry bubble column reactors (SBCRs) for Fischer-Tropsch (F-T) synthesis, taking into account the hydrodynamics, kinetics, heat transfer, and mass transfer was developed. The hydrodynamic and mass transfer data obtained in our laboratories under typical F-T conditions along with those available in the literature were correlated using Back Propagation Neural Network and empirical correlations with high confidence levels. The data used covered wide ranges of reactor geometry, gas distributor, and operating conditions. All reactor partial differential equations, equation parameters and boundary conditions were simultaneously solved numerically.The simulator was systematically used to predict the effects of reactor geometry (inside diameter and height) as well as superficial gas velocity and catalyst concentration on the performance of a large-scale SBCR provided with cooling pipes and operating under F-T conditions with cobalt-supported catalyst and H₂/CO = 2. The performance of the SBCR was expressed in terms of CO conversion, liquid hydrocarbon yield, catalyst productivity, and space time yield. The simulator was also used to optimize the reactor geometry and operating conditions in order to produce 10,000 barrels/day (bbl/day) of liquid hydrocarbons.     

Low-tar,highly burnable gas production from the gasification of pelletized palm empty fruit bunch

Gasification is an attractive method to convert lignocellulosic biomass into a combustible gas mixture for electricity and power generation. To control the tar concentration in the produced gas to be within the allowable limit of downstream applications, it is important for a gasification system to be integrated with a tar removal process. In this study, an integrated gasification system consisting of a downdraft gasifier and a secondary catalytic tar-cracking reactor was designed and tested for the gasification of pelletized oil palm empty fruit bunch. To further purify the producer gas, the system was also integrated with a cyclone, a water scrubber, and a carbon-bed filter. Biomass was fed at a rate of 5 kg/h, while the air equivalence ratio (ER) and the gasification temperature were set at 0.1 and 800°C, respectively. In total, 5 kg of the specially developed low-cost Fe/activated carbons (AC) catalyst was used in the hot gas catalytic tar-cracking reactor. Results indicate that our integrated gasification system was able to produce a clean burnable gas with a lower heating value (LHV) of 9.05 MJ/Nm³, carbon conversion efficiency (CCE) of 79.4%, cold gas efficiency (CGE) of 89.9%, and H₂ and CH₄ concentrations of 29.5% and 10.3%, respectively. The final outlet gas was found to only contain 32.5 mg/Nm³ of tar, thus making it suitable for internal combustion engine (ICE) application.     

Process modelling of dimethyl ether production from Victorian brown coal—Integrating coal drying,gasification and synthesis processes

Power plants using Victorian brown coal operate at low efficiency. Being reactive and spontaneously combustible, dried brown coals cannot be exported either. Synthesis of dimethyl ether (DME) is one option for the production of liquid fuel, an exportable product for power generation and transportation. This paper presents a steady-state process model for DME production using brown coal including drying, gasification and DME synthesis. The yield of the DME was a maximum for H₂ to CO molar ratio of 1.41 and 0.81 at the gasifier outlet and the DME reactor inlet respectively. A process efficiency of 32% and CO₂ emission of 2.91 kg/kg of DME was obtained. Improved yield of DME is achieved when CO₂ is removed from the fuel gas prior to feeding to the synthesis reactor. Integration of waste heat and design of appropriate catalyst for gasification and DME synthesis can result in further improvements in the process.     

基于赤铁矿载氧体的煤化学链燃烧试验

化学链燃烧是一种具有CO₂内分离特性的燃烧方式。以赤铁矿为载氧体,在1 kW_th级串行流化床上进行了煤化学链燃烧试验。讨论了燃料反应器温度对气体产物组分的影响;比较了各反应参数对煤气化效率、煤气化产物的转化效率及碳捕集效率的影响情况,分析了煤中硫的排放问题。试验结果表明：温度由900℃升高到985℃,燃料反应器中CO体积份额逐渐增加,CO₂体积份额逐渐减小,空气反应器中CO₂浓度呈线性下降。燃料反应器温度的升高促进煤气化效率及碳捕集效率大大提高。载氧体量和系统负荷是煤气化产物转化效率的主要影响因素,载氧体量的增加和负荷的增加分别会使煤气化产物转化效率提高和下降。燃料反应器中的硫主要以SO₂形式存在于燃料反应器,随温度的升高,SO₂浓度由515×10^-6逐渐增加到562×10^-6相似文献   

煤气化甲醇-发电联产生产工艺的优化组合

对兖矿国泰公司煤气化甲醇—发电联产生产装置工艺路线的选择进行了分析论证,分别论述了煤气化、净化、燃气发电、甲醇联产等工艺特点,将各工艺路线优化整合后,实际工况的运行指标优于设计指标,可实现煤炭联产系统高效、经济的运行模式。     

固定床气化与气流床水煤浆气化集成的能量与经济分析

针对煤制天然气工艺中固定床气化产生大量含有焦油、酚等难处理物质的废水,提出了将固定床气化和气流床水煤浆气化相结合的气化方式解决废水问题。考察了未分离焦油煤气水直接制浆和分离焦油后酚水再制浆的两种气化集成方式,以煤制天然气项目为基础对其进行能量与经济分析。结果表明:与单一气流床相比,固定床气化和气流床水煤浆气化耦合提高了系统冷煤气效率;当固定床与气流床水煤浆气化干基煤处理量比为2,未分离焦油煤气水直接制浆和分离焦油后酚水再制浆两种气化集成方式的气化系统煤耗分别为563 kg·km^-3(CO+H₂+3.12×CH₄)和599 kg·km^-3(CO+H₂+3.12×CH₄),氧耗分别为212 m³ O₂·km^-3(CO+H₂+3.12×CH₄)和206 m³ O₂·km^-3(CO+H₂+3.12×CH₄),冷煤气效率分别为84.44%和86.74%,总热效率分别为72.53%和74.87%,且副产焦油的气化集成方案与单一固定床气化方案相比,其天然气生产成本增加不明显,经济上可行。     

Experimental study on sawdust air gasification in an entrained-flow reactor

Experiments were performed in an entrained-flow reactor to better understand the processes involved in biomass air gasification. Effects of the reaction temperatures (700 °C, 800 °C, 900 °C and 1000 °C), residence time and the equivalence ratio in the range of 0.22-0.34 on the gasification process were investigated. The behavior of biomass gasification was discussed in terms of composition of produced gas. Four parameters, i.e. the low heating value, fuel gas production, carbon conversion and cold gas efficiency were used to evaluate the gasification. The results show that CO, CO₂ and H₂ are the main gasification products, while hydrocarbons (CH₄ and C₂H₄) are the minor ones. With the increase of the reaction temperature, the concentration of CO decreases, while the concentrations of CO₂ and H₂ increase. The concentrations of CH₄ and C₂H₄ reach their maximum value when the reaction temperature is 800 °C. The optimal reaction temperature is considered to be 800 °C and the optimal equivalence ratio is 0.28 in that the low heating value of the produced gas, carbon conversion and cold gas efficiency achieve their maximum values. The kinetic parameters of sawdust air gasification are calculated basing on the Arrhenius correlation.     

Co-gasification of coal and wood in a dual fluidized bed gasifier

In the last decade the reduction of CO₂ emissions from fossil fuels became a worldwide topic. Co-gasification of coal and wood provides an opportunity to combine the advantages of the well-researched usage of fossil fuels such as coal with CO₂-neutral biomass. Gasification itself is a technology with many advantages. The producer gas can be used in many ways; for electric power generation in a gas engine or gas turbine, for Fischer-Tropsch synthesis of liquid fuels and also for production of gaseous products such as synthetic natural gas (bio SNG). Moreover, the use of the producer gas in fuel cells is under investigation. The mixture of coal and wood leads to the opportunity to choose the gas composition as best befits the desired process. Within this study the focus of investigation was of gasification of coal and wood in various ratios and the resulting changes in producer gas composition. Co-gasification of coal and wood leads to linear producer gas composition changes with linear changing load ratios (coal/wood). Hydrogen concentrations rise with increasing coal ratio, while CO concentrations decrease. Due to the lower sulfur and nitrogen content of wood, levels of the impurities NH₃ and H₂S in the producer gas fall with decreasing coal ratio. It is also shown that the majority of sulfur is released in the gasification zone and, therefore, no further cleaning of the flue gas is necessary. All mixture ratios, from 100 energy% to 0 energy% coal, performed well in the 100 kW dual fluidized bed gasifier. Although the gasifier was originally designed for wood, an addition of coal as fuel in industrial sized plants based on the same technology should pose no problems.