煤直接液化循环溶剂加氢稳定试验研究

在300 m L加氢试验装置上进行加氢稳定试验,考察了反应压力对煤直接液化循环溶剂性质的影响,并通过0.5 L高压釜煤液化试验,考察了煤在不同加氢深度循环溶剂中的液化效果。结果表明,随着溶剂加氢反应压力的升高,循环溶剂密度、黏度及氮含量递减,氢碳原子比及供氢指数递增,循环溶剂性质得到改善,供氢性能得到提高,从而促进煤的转化率和油收率提高。当加氢反应压力由12.5 MPa升至19.3 MPa时,煤的转化率从87.21%提高到88.40%,液化油收率从51.62%提高到55.58%。     

洗油对五彩湾高惰质组煤直接液化性能的影响

以洗油为供氢溶剂,考察了溶煤比、反应温度和氢初压对新疆五彩湾煤样加氢液化性能的影响.结果表明,在煤液化中,洗油部分加氢,生成具有强供氢能力的物质,增强其供氢能力,可以作液化溶剂,且溶煤比由四氢萘为溶剂的3降低到1.75;虽然氢初压为8.0 MPa,但反应终压为16.3 MPa,与四氢萘为溶剂时相当;油产率达到59.24％,转化率达到81.05％.     

秸秆与兖州煤共液化反应条件的研究

在高压反应釜内,以四氢萘为供氢溶剂,Fe2O3＋S为催化剂,研究了温度、反应时间、初始氢压、配比对兖州煤与秸秆共液化的影响。结果表明,提高反应温度,转化率、油产率增加;延长反应时间对转化率、油产率的影响较小;升高初始氢压,转化率、油产率刚开始增加,6 MPa以后增幅趋缓;在m（秸秆）∶m（兖州煤）=0.5∶9.5时,共液化的油产率为60.45%,比兖州煤单独液化的油产率提高了4.17%;在m（兖州煤）∶m（秸秆）=9.5∶0.5,440℃,8 MPa,90 min的条件下,共液化转化率和油产率达到最大,分别为83.58%和63.1%。     

新疆淖毛湖煤加氢液化特性及液化产物中氢的分布规律

以新疆淖毛湖煤和四氢萘为原料,在2L高压釜中进行加氢液化实验,开展新疆淖毛湖煤直接液化过程调控研究,考查了温度、压力、时间及催化剂对氢耗、气产率、转化率、油产率和沥青类物质产率的影响规律,探讨了复杂多相体系液化产物中氢的分布规律,揭示了煤直接加氢液化反应与氢分布规律的内在联系.结果表明:在420℃,15MPa和60min的反应条件下,淖毛湖煤的转化率为94%,油产率为65%,是适宜直接液化的优良煤种;氢较均匀地分布在淖毛湖煤加氢液化的轻质产物(水、150℃馏分油、150℃～260℃馏分油和260℃～350℃馏分油)中,在350℃重质馏分油中分布最高,接近30%;氢在液化产物中的分布与加氢液化反应效果呈现出正相关特征.     

氢气在无催化煤液化中的反应机理

采用平衡液相取样法气体溶解度测定装置测定了氢气在萘中的溶解规律,并采用间歇式微型反应釜研究了氢气在无催化煤液化中的反应机理.结果表明:1)氢气在萘中的溶解随着温度和压力的升高而增加,溶解速率先快后慢,在5min时达到最大溶解量的76.21%左右,直到30min达到平衡;2)在萘溶剂的无催化煤液化反应中,氢气的溶解不是控制步骤,溶解氢参与液化反应的速度才是控制步骤;3)在较短时间的萘溶剂无催化煤液化时,氢气在萘溶剂中的预溶解提高了无催化煤液化的总转化率,其主要原因是部分预溶氢提前活化,使得煤液化反应初期活性氢增加;4)在较长时间的萘溶剂无催化煤液化时,预溶氢对总转化率的提高很小,但促进了液化产物的进一步裂解加氢轻质化.     

义马煤直接液化性能的研究

利用高压反应釜,采取程序控制升温的方法,以义马煤为原料,循环油为溶剂,Fe2O3为催化剂和S为助催化剂,在不同反应时间、温度和初始氢压下,测定了义马煤直接液化效果的影响因素.结果表明,随着温度升高,转化率呈减小趋势,而油产率随着反应温度的增加呈现出先增加后减小的趋势,在380℃时油产率达到最大值;随着初始压力的增加,转化率和油产率都有所增加,但增加幅度很小,在9 MPa时油产率达到最大值;随着反应时间的增加,转化率和油产率都有所增加,在120 min时油产率和转化率均达到最大值.     

煤直接液化柴油深度加氢脱芳烃反应动力学

为了研究煤直接液化柴油加氢脱芳烃反应规律,采用贵金属加氢催化剂在30 mL连续加氢实验装置上对煤直接液化柴油进行了深度加氢实验,考察了不同反应压力6～12 MPa,反应温度80～240℃,体积空速0.4～1.2 h-1条件下煤直接液化柴油芳烃饱和行为。研究表明,在合适的加氢条件下产品油中芳烃质量分数可以降低到0.01%以下。将外扩散传质过程与芳烃加氢反应过程相结合,通过动力学方程推导建立了直接液化柴油芳烃加氢反应动力学模型方程。模型预测结果表明,随着流体空塔流速提高,外扩散有效因子先增大然后趋于1,芳烃转化率呈先增大后趋于不变;反应温度越高,消除外扩散影响所需的流体空塔流速越大。可通过模型预测得到,在消除外扩散影响下,保证直接液化柴油馏分油加氢后芳烃含量低于0.01%所需的反应温度和体积空速。     

甲烷气氛下铁基催化剂对低阶煤温和液化的影响

针对煤直接液化的高温高压苛刻反应条件和高昂的氢气成本问题,通过降低煤液化反应温度、压力和更换供氢气氛等方法来优化工艺过程。选用四种铁基催化剂研究低阶煤在甲烷气氛下温和液化的反应特性,研究结果表明：神华黑山长焰煤HS在温度350℃、初始压力3 MPa的甲烷气氛下液化产物为轻质气体、液化油和沥青质;以FeSO₄为催化剂时沥青质的产率最高达到8.03%,并将煤液化的转化率提升了6.10%;以FeS为催化剂时油气产率提升了3.48%;助剂硫元素的加入对煤液化反应总转化率的提升有着重要作用;Fe粉、Fe+S和FeS催化剂的加入有助于提升煤液化油中单环芳烃的含量。     

煤直接液化重质产品油的催化加氢实验研究

在30mL油品加氢实验装置上,进行煤直接液化全馏分油中重质油(320℃)加氢实验,考察反应温度、压力和体积空速变化对加氢生成油物性的影响.结果表明,油品的脱硫率和脱氮率与反应温度和反应压力成正比,与体积空速成反比;升高反应温度和反应压力或降低体积空速,都有利于加氢油品中单环芳烃和双环芳烃质量分数的增加、多环芳烃质量分数的减少.计算得到的油品供氢指数(IPDQ)增加,从而溶剂供氢能力增加.不同加氢条件下得到的油品物性表明,反应温度为380℃,压力为19MPa,体积空速为0.8/h时,得到的重质馏分油作为煤液化循环溶剂使用时供氢性最好.     

氢气在煤高温快速液化中的作用

首先利用实验室建立的一套平衡液相取样法实验装置测定了氢气在四氢萘和萘中的溶解规律,其次通过间歇式微型反应釜研究了氢气在煤高温快速液化中的作用。结果表明:①氢气在溶剂中的溶解度随温度与压力的增加而增加;在一定的温度与压力下,氢气在四氢萘和萘中的溶解度在5 min内达到最大溶解量的78.54%左右,之后溶解度开始逐步缓慢上升直到30 min时达到最大溶解量;②在充足的四氢萘作为溶剂的液化反应中,氢气对于煤高温快速液化反应几乎没有影响,活性氢主要来源于溶剂;在萘作为溶剂的液化反应中,钼酸铵催化剂促进了氢气参与反应,但是总转化率的变化较小,仅仅促进了沥青烯向油方向的转化。③压力对于煤高温快速液化中四氢萘的供氢性能有影响。     

飞灰对五彩湾煤低压直接液化性能影响研究

在溶煤比为2.75∶1,氢初压为6.0MPa和反应时间为60min条件下,考察了温度、飞灰加入量、CoSO4和NiSO4用量及其加入方式等因素对五彩湾煤直接液化性能的影响.结果表明,在给定的条件下,在飞灰加入量为3%(daf,质量分数)和温度为415℃时,可获得最大油产率为64.59%;当CoSO4和NiSO4与飞灰和煤样机械混合加入时,对液化油产率和转化率产生负效应;当NiSO4和CoSO4浸渍担载加入时,油产率分别达到68.01%和66.58%.尽管煤质分析结果表明该煤样加氢液化性能较差,但以飞灰、CoSO4和NiSO4为催化剂时,还是获得了良好的液化效果.     

超细FeS对五彩湾煤直接液化性能的影响

以硫酸亚铁为铁源,硫化钠为沉淀剂,采用液相沉淀法合成了超细FeS催化剂。以四氢萘为溶剂,反应温度430℃、氢初压6.0 MPa、反应时间60 min、溶煤比2∶1条件下,探讨超细FeS催化剂对五彩湾煤直接液化性能的影响。结果表明：硫酸亚铁基超细FeS粒子形貌均一,呈细棒状;五彩湾煤直接液化实验的油产率、液化率和转化率,以2.0%（wt,以活性金属元素计,相对于干燥无灰煤,下同）超细FeS为催化剂的实验分别达到56.15、73.29和81.21%（wt,相对于干燥无灰煤,下同）,高于相同条件下,以3.0%分析纯Fe2O3为催化剂的实验产率（分别是44.00、49.33和62.05%）。     

溶胀煤制备及煤加氢液化性能的研究

在自然和微波条件下,对五彩湾煤进行溶胀处理,进行煤质、电镜、热解、煤的结构-化学指数分类、加氢液化产率和液化残渣热解的分析。实验结果表明:五彩湾煤自然溶胀煤样和微波溶胀煤样的层状和裂纹显著增加,失重量明显增大。煤加氢液化测试结果表明,在氢初压6.0 MPa、溶煤比1.75:1、反应温度450℃和反应时间60 min条件下,气产率由原煤的9.7%,降低到两种溶胀煤均在3.4%左右;油产率由原煤的55.2%,提高到自然溶胀煤的70.1%和微波溶胀煤的74.0%;转化率由原煤的76.8%,增加到自然溶胀煤的82.1%和微波溶胀煤的84.8%。可见,经过溶胀处理,煤加氢液化效果显著。     

高惰质组分五彩湾煤直接液化性能研究

以新疆五彩湾煤为研究对象,进行了煤质和热解分析,考察了溶煤比、反应时间、氢初压和反应温度对其加氢液化效果的影响.结果表明,尽管五彩湾煤惰质组含量高达81.5%,镜质组最大反射率达到0.73%,挥发分低于37%,H/C仅为0.59,但在氢初压仅为6.0MPa,溶煤比1.75和反应时间60min条件下,其最佳液化温度为450℃,油产率和转化率分别达到55.20%和76.76%,仍然具有良好的液化性能.     

Reaction mechanism of coal hydrogenation. 3. Effect of coal type

Seven coals have been hydrogenated in naphthalene and phenanthrene under 10 MPa (initial pressure) of hydrogen with a stabilized niekel catalyst at 400°C for 15 min. Preasphaltene, asphaltene and oil conversions and solvent conversion were measured. The amounts of hydrogen absorbed by coal and by solvent were calculated. Coal conversion and the amount of hydrogen absorbed by coal decreased, while the amount of hydrogen absorbed by solvent increased, with increase in coal rank. The ratio of the amounts of hydrogen absorbed by coal and by solvent showed a good correlation with conversion to benzene- and n-hexanesoluble materials. Naphthalene and phenanthrene gave similar results, suggesting that the coal was hydrogenated directly by gaseous hydrogen.     

Kinetics of short contact time coal liquefaction. Part I: Effect of operating variables

The liquefaction kinetics of Powhatan No.5 mine coal (Pittsburgh Seam) in the presence of SRC-II recycle solvent at short contact times (<10 min) and temperature and pressure ranges of 573–723 K and 10.3–13.8 MPa is examined in a well-mixed reactor. In the initial stages of liquefaction, while overall coal conversion (tetrahydrofuran solubles) increases with temperature, oil (pentane solubles) is lost with an increase in temperature. An increase in solvent-to-coal ratio results in an increase of conversion. The initial coal particle size distribution, total pressure, and nature of gas phase (nitrogen or hydrogen) have no significant effect on the production of any of the product of liquefaction for contact times up to 10 min. A lumped kinetic model is presented to describe the product distribution.     

液化条件下煤中共价键断裂难度降低原因分析

通过对四十余种常见煤液化模型化合物键能的分类、排序与分析,发现仅桥键的热致裂解远不足以让煤直接液化的转化率达到常见的70%以上的转化率.除了由于煤的高芳香性导致共振稳定和反应时间延长导致活化能量积累作出贡献以外,还有三个因素对桥键的广泛断裂和煤液化的高转化率作出了贡献,即溶剂、氢压和矿物质等催化剂.     

Liquefaction mechanism of Wandoan coal using tritium and 14C tracer methods: 2. Liquefaction using 3H labelled gaseous hydrogen

Tritium labelled gaseous hydrogen was used to clarify the role of gaseous hydrogen in coal liquefaction. Wandoan coal was hydrogenated under 5.9 MPa (initial pressure) of ³H-labelled hydrogen and in unlabelled solvents such as tetralin, naphthalene and decalin at 400 °C and for 30 min in the presence or absence of NiMoAl₂O₃ catalyst. Without a catalyst, liquefaction proceeded by addition of the hydrogen from donor solvent. The NiMoAl₂O₃ catalyst enhanced both hydrogen transfer from gas phase to coal and hydrocracking of coal-derived liquids. With NiMoAl₂O₃ catalyst, liquefaction in naphthalene solvent proceeded through the hydrogen-donation cycle: naphthalene → tetralin → naphthalene. The amount of residues showed that this cycle was more effective for coal liquefaction than the direct addition of hydrogen from gas phase to coal in decalin solvent. The ³H incorporated in the coal-derived liquids from gas phase was found to increase in the following order: oil < asphaltenes < preasphaltenes < residue.     

Liquefaction of sawdust for liquid fuel

Pressurized liquefaction of sawdust was carried out in an autoclave in the presence of solvent under cold hydrogen pressure ranging from 2.0 to 5.5 MPa at the temperature range of 150C–450°C. The reaction time varied from 5 to 30 min. Investigations were made on the effects of temperature, reaction time, cold hydrogen pressure and solvent on the liquefaction process. Results indicate that liquefaction of sawdust can start at a temperature of 200°C, much lower than that for coal in a hydrogen-donor solvent, e.g., tetralin which was used in this run of experiment. Oil yield increase with the rise either in temperature and in cold hydrogen pressure or with the longer reaction time.     

Study on coal liquefaction characteristics of Chinese coals

The New Energy and Industrial Technology Development Organization (NEDO) has implemented the collaborative research work with China Coal Research Institute (CCRI) on the liquefaction of Chinese coals for about 20 years. A total of 53 runs in a 0.1 t/d bench scale coal liquefaction plant installed at the CCRI were made on 27 kinds of coal selected among coals existing throughout China. The bench plant was operated in a direct hydrogenation (DH) mode and NEDOL mode. In the DH mode, 25 MPa of reaction pressure was employed with decrystallized anthracene oil used as the solvent, while 17 MPa of reaction pressure was employed and hydrogenated solvent was used in the NEDOL mode. This study confirmed that the NEDOL mode, which uses comparatively mild in liquefaction conditions, can liquefy each coal with the high oil yield more efficiently, and is capable of liquefying about 60% of inertinite in high inertinite coals.