氧气对褐煤水蒸气气化半焦的活化及机理

以胜利褐煤为原料,利用一段流化床/固定床石英反应器,进行N_2/O_2/H_2O/H_2O+O_2气氛的褐煤热解/气化实验。采用BET、Raman、FT-IR、微波消解ICP-AES、TGA等技术表征半焦。研究氧气添加对气化反应以及半焦结构和反应性的影响,解析了氧气对气化半焦的活化机理。结果表明,氧气添加可以改变半焦结构,活化半焦,从而促进转化率、H_2产率和CO_2产率的提高。氧气对气化半焦的活化作用主要包括两个方面,一是芳核与氧气发生氧化分解反应,破坏了芳环大π键,形成了新的官能团,从而促进了反应(C+H_2O→H_2+CO)的发生;二是随反应的进行,芳香大环(≥6)结构解聚为芳香小环(3-5)结构,同时氧原子进入芳核,形成缺陷位C-O-C,从而导致半焦微晶结构的缺陷程度提高、缩聚程度降低,进而导致半焦反应性和表面吸附作用提高,促进反应(CO+H_2O→H_2+CO_2)的发生。     

Condensation Characteristics of Flue Gas/Steam Mixtures with Fine Lignite and Ash Particles along Horizontal Finned Tube Bundles

The condensation behavior for a gas/steam mixture with fine lignite particles and lignite ash particles is experimentally investigated as the particles flow over horizontal finned tube bundles. The effects of the gas velocity, inlet temperature of cooling water, excess air coefficient, and particle dimension are discussed. The total mass flow rate of the condensate and the condensation heat transfer coefficient for flue gas including particles are higher than those of flue gas excluding particles when Reynolds number is higher than 2,300. The area covered by ash depositions tends to grow from the leeward toward the windward side with increasing particle diameter.     

Biologically derived value-added products from coal

The Idaho National Engineering Laboratory (INEL) has for several years conducted research in the area of coal bioprocessing. Fundamental and exploratory research has been directed toward the conversion of coal to cleaner fuels and the remediation of harmful byproducts of coal utilization. Specific research projects have involved coal depolymerization, coal solubilization, removal of organosulfur and pyritic sulfur from coal, the molecular biology of coal-modifying microorganisms, removal of ash-forming minerals from coal, conversion of coal combustion gases, and the development of novel coal bioreactors. Notable research accomplishments include elucidation of mechanisms by which microorganisms solubilize different portions of coal, discovery and characterization of microorganisms capable of depolymerizing macromolecular coal, discovery of microorganisms capable of removing organosulfur from coal, development of technologies critical to analyzing biologically mediated depolymerization and organosulfur removal, novel methods of pyritic sulfur removal, novel methods of removal (and conversion) of CO₂, SO_x, and NO_x from combustion gases, and new technologies for bioconversion of waste gypsum generated in coal combustion gas scrubbers.     

镧系收缩效应对稀土-煤相互作用的影响及煤中有机态稀土的赋存形式研究

通过酸洗脱灰及腐殖酸提取等方法对伊敏褐煤进行处理,并应用ICP-MS对处理前后的样品进行了稀土元素测定。在对脱灰前后稀土元素与灰分和C、H、O等有机组成元素的相关性以及稀土元素在腐殖酸中的赋存特征分析的基础上,认为煤中稀土元素-有机质相互作用受煤化作用过程中的脱氧、脱氢和增碳作用控制。稀土与煤中各类官能团相互作用形成四类有机态稀土元素复合物,第一类是与被烷基侧链高度取代的芳香结构单元形成的复合物;第二类是与氢化芳香结构单元形成的复合物;第三类是与低取代度的芳香结构单元形成的复合物;第四类是与含氧官能团作用形成的复合物,后两类的稳定性差。这些有机态稀土元素复合物的稳定性在总体受镧系收缩效应控制的基础上,还受稀土元素化学价态的影响;重稀土与有机质形成的有机态稀土元素复合物的稳定性大于轻稀土。轻稀土在原煤中和腐殖酸的结合不稳定,且具有与镧系收缩相反的效应;轻稀土在脱灰煤中和腐殖酸的结合,与中稀土、重稀土在原煤和脱灰煤中腐殖酸结合规律相同,都体现了良好的镧系收缩效应。     

橄榄石基固体热载体影响褐煤热解产物分布的分析

为了提高固体热载体煤热解工艺中焦油的品质,降低焦油中沸点大于360 ℃的重质组分含量,本实验采用固定床反应器,在450~600 ℃下进行褐煤固体热载体快速热解反应.分析对比了橄榄石基和石英砂固体热载体对褐煤热解产物收率、焦油馏分、气体组成的影响.结果发现,Co能改变煤内部挥发分氢元素的分布,橄榄石负载Co热载体能将焦油中重质组分转化为轻质焦油和热解气.热解温度为550 ℃时,与橄榄石相比,负载Co的橄榄石固体热载体使焦油收率提高了19.2%.与石英砂相比,负载Co的橄榄石固体热载体使焦油中重质组分含量降低了17.0%,轻质组分收率达5.1%,其中,轻油、酚油和萘油分别提高了19.6%、17%和15.2%,气体产物中H₂、CH₄含量下降.     

先锋褐煤在离子液体1-丁基-3-甲基咪唑三氟甲磺酸盐作用下热溶解聚及其产物分析

考察了先锋褐煤(XL)在高温稳定性很好的离子液体1-丁基-3-甲基咪唑三氟甲磺酸盐([Bmim]OTf)中的解聚性能,并对其在不同热溶条件下解聚所得热溶物和残煤进行了分析表征。结果表明,[Bmim]OTf对XL具有较好的解聚性能。在280℃,[Bmim]OTf/XL为3.5下解聚4h,[Bmim]OTf对XL的萃取率(以四氢呋喃可溶物计)为20.1%。四氢萘(THN)、H₂和催化剂ZnCl₂的加入可显著促进XL在[Bmim]OTf中的解聚,相比于XL在[Bmim]OTf作用下的萃取率,THN、H₂和催化剂ZnCl₂的加入使可溶物的收率分别提高到30.0%、36.9%和46.8%。产物分析结果表明,在[Bmim]OTf热溶解聚XL的过程中THN的加入使得XL经离子液体[Bmim]OTf解聚所得热溶物中氢键的数量明显增加;H₂和ZnCl₂的添加分别增加了产物中脂肪烃和芳烃的含量。     

煤炭腐植酸的硅烷化

研究了风化煤、褐煤腐植酸（ＨＡ）及其氧解产物（ＮＨＡ）与卤硅烷的缩合反应。产物的组成分析、红外、ＤＴＡ、吸附性能和表面张力等测定结果表明，ＨＡ及ＮＨＡ同卤硅烷的反应活性与其羧基含量有较好的相关性，卤硅烷的反应活性ＲｎＳｉＣｌ４－ｎ〉ＰｈｎＳｉＣｌ４－ｎ（苯基氯代硅烷）。硅烷化产物具有较好的热稳定性与表面活性。     

Thermal Analysis Applications In Fossil Fuel Science. Literature survey

In this study, instances where thermal analysis techniques (differential scanning calorimetry, thermogravimetry, differential thermal analysis, etc.) have been applied for fossil fuel characterisation and kinetics are reviewed. The scientific results presented clearly showed that thermal analysis is a well-established technique used in fossil fuel research area. The literature survey showed that thermal methods were important not only theoretically but also from a practical point of view. This revised version was published online in August 2006 with corrections to the Cover Date.     

Combustion characteristics of lignite and oil shale samples by thermal analysis techniques

In this research thermal analysis and kinetics of ten lignite's and two oil shale samples of different origin were performed using a TA 2960 thermal analysis system with thermogravimetry (TG/DTG) and differential al analysis (DTA) modules. Experiments were performed with a sample size of ~10 mg, heating rate of 10°C min^-1. Flow rate was kept constant (10 L h^-1) in the temperature range of 20-900°C. Mainly three different reaction regions were observed in most of the samples studied. The first region was due to the evaporation of moisture in the sample. The second region was due to the release of volatile matter and burning of carbon and called as primary reaction region. Third region was due to the decomposition of mineral matter in samples studied. In kinetic calculations, oxidation of lignite and oil shale is described by first-order kinetics. Depending on the characteristics of the samples, the activation energy values are varied and the results are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.