介质阻挡放电辅助甲烷蒸汽重整的实验研究

利用介质阻挡放电辅助甲烷蒸汽重整试验平台进行了大量试验,基于试验数据系统地分析了350-500℃温度下蒸汽甲烷摩尔比(S/C)、反应物驻留时间、壁面温度及输入功率等对甲烷转化率、有效碳回收率及产物选择性等指标的影响规律,并考察了不同影响因素之间的相互作用关系。研究发现:驻留时间对各指标的影响最为明显,在不同壁面温度下,随着驻留时间的增加,产物选择性出现转折性变化,由60%左右下降到20%左右;与驻留时间的影响不同,随着输入功率或S/C的增加,重整特性的各评价指标均呈现缓慢增长趋势;而温度对等离子体辅助甲烷蒸汽重整结果是否有影响与驻留时间、输入功率等参数有关,只有当驻留时间大于0.59 s时,温度对重整反应的影响变得较小,且当输入功率也大于80 W时,温度对重整反应不再有影响。     

甲烷快速部分氧化重整试验研究

采用常规浸渍法制备了Rh/α-Al2O3催化剂,建立了甲烷快速部分氧化重整试验体系。通过控制变量法,考察了甲烷快速部分氧化重整反应中反应条件参数(CH4/O2、反应气体预混合温度、空速)变化对反应物的转化率、反应产物及分布的影响。试验结果表明,在试验条件下,CH4的转化率始终大于85%,O2转化率接近100%,CO的选择性为85%左右,H2的选择性为40%～60%。反应过程大致为催化剂入口处的部分氧化反应和下游的水蒸气重整,大部分的CO由部分氧化产生,而H2的产生受水蒸气重整反应的影响较大;随着反应温度的上升,CH4的转化率上升,CO,H2的选择性也上升;随着空速的增大,H2的选择性减小,表明甲烷催化部分氧化反应是一个受传质控制的反应。     

铂基催化剂快速部分催化氧化甲烷的研究

以Al2O3为载体,采用浸渍法制备Pt/Al2O3催化剂,通过测量重整反应过程中催化剂的温度分布情况,研究了改变甲烷快速部分氧化重整反应中反应条件(反应气体预混合温度、N2体积比例、CH4/O2比)对反应物的转化率及产物选择性的影响.研究发现,催化剂床层温度的上升可以促进CH4的转化,使H2和CO的选择性升高且H2与C...     

基于太阳能热驱动甲烷重整制氢的燃料电池发电系统性能研究

该文采用Aspen Plus软件建立膜反应器重整制氢及燃料电池模型,根据拉萨某日太阳能直接辐射强度（DNI）变化计算太阳能可供使用的能量,作为外热源输入重整系统,并分析反应温度、水碳比（S/C）及DNI对该系统各性能指标的影响,性能指标包括甲烷转化率、H₂收率、电池功率及电压、太阳能转换为氢能的效率。结果表明：反应温度为500 ℃,S/C为2.5时有利于太阳能甲烷湿重整反应;系统日性能结果显示在某日10:00—20:00时,电池输出功率120 kW,太阳能-化学能转化效率0.368,系统发电效率0.225。     

甲烷化学链重整制备合成气技术中的钙钛矿型载氧体制备及动力学特性

采用燃烧法、微乳液法、共沉淀法和溶胶-凝胶法4种方法制备钙钛矿型氧化物La Fe O3作为载氧体用于甲烷化学链重整制备合成气过程,利用X射线衍射(XRD)、扫描电镜(SEM)、H2程序升温还原(H2-TPR)、比表面积分析(BET)等技术对载氧体进行表征,在固定床反应装置上考察4种方法制备的La Fe O3与甲烷的反应性能,寻求适用于甲烷化学链重整过程载氧体的最佳制备方法,然后通过H2-TPR的多速率升温过程探讨La Fe O3的还原动力学。结果表明,4种方法制备得到的载氧体均形成钙钛矿结构,溶胶-凝胶法和燃烧法制备的La Fe O3纯度和结晶度均更好,无杂相生成;从CH4转化率、n(H2)/n(CO)、CO和H2选择性等方面综合考虑,燃烧法制备得到的载氧体反应性能最好,用于甲烷化学链重整制备合成气的生成效果最好。H2-TPR的动力学计算表明,La Fe O3载氧体的低温吸附氧还原活化能为97.001 k J/mol,高温晶格氧还原活化能为30.388 k J/mol。     

生物质合成气的化学当量比调整

针对生物质气化气中硫化物少、V（H2／CO）低和V（CO2）高的特点，采用气化炉内铁系高温变换催化剂和气化炉外钛促进的钴钼耐硫催化剂进行水煤气变换调整H2／CO比，添加部分沼气重整过量CO2，对生物质合成气化学当量比调整进行了实验研究。结果表明：气化炉内铁系催化剂调整效果不明显；在高温低硫的生物质气化气中，钛促进的钴钼耐硫催化剂具有较高的变换活性，CO转化率达到80％以上，合成气H2／CO比在1-8范围内可调；在V（CH4，CO2）=1、常压、750℃和镍基催化剂作用下沼气重整过量CO2，制备出宽V（H2／CO）、V（CO2）和V（CH4）均低于5％（摩尔百分比）的合成气；通过水煤气变换过程结合沼气重整过程，可依据目的产物合成的要求，制备合适化学当量比、高碳转化率的生物质合成气。     

用于焦炉煤气重整合成气的管式透氧膜反应器的研制及其运行性能

采用热注浆法成功地制备了致密的混合导体BaCo0.7Fe0．2Nb0.1O3-δ（BCFNO）透氧膜管,应用在焦炉煤气中甲烷部分氧化制合成气反应中,可以利用透氧膜以空气为氧源和焦炉煤气中的甲烷反应制合成气,实现膜分离制氧和甲烷部分氧化反应的一体化。试验结果表明,当反应温度在875℃时,膜的透氧量为8．7mL／（cm^2·min）,焦炉煤气中甲烷的转化率可以达到94％以上,H2的选择性在90％左右。试验结果还表明,透氧膜管的性能可靠稳定,经过长时间的运行膜管没有出现破裂,在富氢焦炉煤气气氛下表现出很好的稳定性。     

基于甲烷催化部分氧化的SOFC性能研究

基于固体氧化物燃料电池的热电联供系统可以实现能源的梯级利用,实现较高的效率,降低污染排放,具有很好的发展前景.针对该系统中传统重整器存在的高能耗等问题,对新型重整方式催化部分氧化进行了研究.本文首先研究了催化剂为0.5%Rh/Al2O3,以甲烷为燃料时CPOX的性能变化规律.通过调节控制温度、体积空速和入口气C/O比,研究了不同工况下CH4转化率、H2选择性、CO选择性和甲烷重整效率的变化规律,对工况进行优化.在优化工况下,即温度800℃、体积空速200 min-1、C/O摩尔比为1.0时,实现了催化部分氧化与微管式固体氧化燃料电池四管电堆的直接耦合,并对电池性能进行测试,结果表明,最大功率可达到纯氢燃料的87.8%.     

定壁温下甲烷自热重整产氢暂态特性数值模拟

采用甲烷自热重整的详细反应机理,通过数值模拟的方法研究了恒壁温、微型直通道内的CH4、O2、H2O镍基催化剂上的自热重整反应。重点分析了混合物组分及质量流量对自热重整产氢暂态特性的影响。结果表明,在较高温度下,微型反应器出口H2产量达到最大值所需的时间受混合气质量流量影响较大,而受混合物组分影响很小;氢气产量达到稳定所需的时间随H2O、CH4摩尔比的增大而缩短,随O2/CH4摩尔比的增大而增长。CH4/O2/H2 O摩尔比为1∶0.5∶3.5时,氢气体积分数可在90 ms时稳定于54%。     

以焦炉煤气为原料采用透氧膜反应器部分氧化生产合成气的试验

采用钙钛矿型致密透氧膜对焦炉煤气中的甲烷部分氧化制合成气进行了膜反应试验研究。结果表明，反应温度在875℃，膜透氧量为10mL／（cm^2·min），焦炉煤气中甲烷的转化率在92%以上，产物H2和CO的选择性在90％以上。工作过程中，透氧膜没有出现破裂，重整试验后透氧膜反应侧仍能保持钙钛矿相结构，显示了很好的稳定性。     

Hydrogen production via steam reforming of coke oven gas enhanced by steel slag-derived CaO

Steel slag, a waste from steelmaking plant, has been proven to be good candidate resources for low-cost calcium-based CO₂ sorbent derivation. In this work, a cheap and sintering-resistance CaO-based sorbent (CaO (SS)) was prepared from low cost waste steel slag and was applied to enhance catalytic steam reforming of coke oven gas for production of high-purity hydrogen. This steel slag-derived CaO possessed a high and stable CO₂ capture capacity of about 0.48 g CO₂/g sorbent after 35 adsorption/desorption cycles, which was mainly ascribed to the mesoporous structure and the presence of MgO and Fe₂O₃. Product gas containing 95.8 vol% H₂ and 1.4 vol% CO, with a CH₄ conversion of 91.3% was achieved at 600 °C by steam reforming of COG enhanced by CaO (SS). Although high temperature was beneficial for methane conversion, CH₄ conversion was remarkably increased at lower operation temperatures with the promotion effects from CaO (SS), and CO selectivity has been also greatly decreased. Reducing WHSV could increase methane conversion and reduce CO selectivity due to longer reactants residence time. Reducing C/A could increase methane conversion and hydrogen recovery factor, and also decrease CO selectivity. When being mixed with catalyst during SE-SRCOG, CaO (SS) with a uniform size distribution favored methane conversion due to the high utilization efficiency of catalyst. Promising stability of CaO (SS) in cyclic reforming/calcination tests was evidenced with a hydrogen recovery factor >2.1 and CH₄ conversion of 82.5% at 600 °C after 10 cycles using CaO (SS) as sorbent.     

Plasma dry reforming of methane in an atmospheric pressure AC gliding arc discharge: Co-generation of syngas and carbon nanomaterials

An alternating-current (AC) gliding arc reactor has been developed offering a new route for the co-generation of syngas and value-added carbon nanomaterials by plasma dry reforming of methane. Different carbon nanostructures including spherical carbon nanoparticles, multi-wall carbon nanotubes and amorphous carbon have been obtained as by-products of syngas generation in the plasma system. Optical emission spectra of the discharge demonstrate the formation of different reactive species (Al, CO, CH, C₂, H_α, H_β and O) in the plasma dry reforming reaction. The effect of different operating parameters (feed flow rate, input power and CH₄/CO₂ molar ratio) on the performance of the plasma process has been evaluated in terms of the conversion of feed gas, product selectivity and energy conversion efficiency. It is interesting to note that gliding arc plasma can be used to generate much cleaner gas products of which syngas is the main one. The results also show that the energy efficiency of dry reforming using gliding arc plasma is an order of magnitude higher than that for processing using dielectric barrier or corona discharges. Both of these can be attributed to the higher electron density in the order of 10²³ m⁻³ generated in the gliding arc plasma.     

生物质鼓泡流化床气化特性的空气当量比影响分析

在鼓泡流化床生物质气化器内,以空气为气化介质,对木屑进行了常压气化试验研究。选择空气当量比ER为0．13～0．33进行试验,研究了在气化温度为760％、810～12和860℃条件下对气化结果的影响。试验结果表明：主要燃气成分含量H2：6．2％～14．1％,CO29．9％～30．2％,CH4：1．6％～11．2％,产气率：1．0m3／kg～1．740／kg,产气低位热值：3526kJ／m3～9184kJ／m3,碳转换率：52．3％～82．3％,气化效率38％～69．1％。     

An experimental study of syn-gas production via microwave plasma reforming of methane,iso-octane and gasoline

A newly developed microwave plasma system for fuel reforming was tested for three different hydrocarbon fuels. The microwave plasma system was powered by a low cost commercial magnetron and power supply. The microwave power was delivered to the nozzle from the magnetron via a coaxial cable, which offers tremendous flexibility for system design and applications. A non-premixed configuration was achieved by delivering a separate stream of fuel to the plasma plume, which is composed of diluted oxygen only. The feasibility of syn-gas production capability of the microwave plasma system was demonstrated and the reforming characteristics of methane, iso-octane and gasoline were compared. The effects of input power, injected fuel amount, total flow rate and O/C ratio were evaluated. The production rates of both hydrogen and carbon monoxide were proportional to the input power and the inverse of the total flow rate. As a result, the maximum efficiency of 3.12% was obtained with iso-octane for power consumption of 28.8 W, O/C ratio of 1, and 0.1 g/min of fuel supply. Liquid fuels produced more syn-gas and showed better efficiency than methane for the same input powers and O/C ratios.     

Pyrolysis of methane via thermal steam plasma for the production of hydrogen and carbon black

Methane pyrolysis for the production of hydrogen and solid carbon was studied in plasma reactor PlasGas equipped with a DC plasma torch with the arc stabilized by a water vortex. Steam plasma is produced by direct contact of electric arc discharge with water surrounding the arc column in a cylindrical torch chamber. The composition of the gas produced was compared with the results of the equilibrium calculations for different flow rates of input methane. We have found that for the net plasma power 52 kW the optimal flow rate of the input methane was between 200 slm and 300 slm, for which high methane conversions of 75% and 80% are achieved. For the flow rate of 500 slm, the methane conversion is only 60%; however, the output still consists of a mixture of hydrogen, methane and solid carbon, without other unwanted components. For the flow rate of 100 slm, the methane conversion is 88%. For 100 and 200 slm of input methane the energy excess for the reaction with respect to the calculated value is 16 kW and 4 kW. On the other hand, for 300 and 500 slm of input methane we have the energy lack of 10 kW and 38 kW. The solid carbon produced was composed of well-defined spherical particles of the size about 1 μm. Comparison with the steam and dry reforming of methane in the same system shows that the presence of oxygen increases the methane conversion, despite lower available energy produced.