DISSOLUTION OF COALS NEAR CRITICAL CONDITIONS

ABSTRACT

Two lignites and one bituminous coal were extracted with benzene, toluene and pyridine at both sub and overcritical conditions in a specially designed experimental system which enabled easy solid-liquid separation. Extract yields increased somewhat at overcritical conditions due to more thermal decomposition. The differences between the power of the solvents were not apparent for the lignites, whereas the solubility in pyridine of the bituminous coal was very much higher than those in benzene and toluene. The amounts of oils, asphaltenes and preasphaltenes in the extracts depended on the type of coal and the solvent.     

EXTRACTION KINETICS OF COALS AT SUBCRITICAL AND SUPERCRITICAL CONDITIONS

ABSTRACT

The extraction kinetics of two lignites and one bituminous coal with benzene, toluene and pyridine were studied at both sub and supercritical conditions in a batch reactor equipped with a coal basket. The time-extract yield data of lignites at supercritical conditions could'nt be treated due to severe thermal decomposition and heating-up effects. The data for Zonguidak coal and those for subcritical extraction of Cizre lignite could be fitted into a first order rate equation with the rate constants changing 0·02-0·05 min^?1 range.     

THE EXTRACTION OF COALS WITH PYRIDINE AND TOLUENE AT 350°C

The extraction of three coals with mixtures of toluene and pyridine at 350^°C were compared. The conversion of both the bituminous and sub-bituminous coals Increased as the amount of pyridine in the mixture Increased up to ca 60% pyridine at a constant gas density of 0.64 g/ml. However, there was no Improvement in conversion for the brown coal when toluene was replaced with pyridine. The difference between pyridine and toluene conversion decreased as the gas density decreased. The high solvent efficiency of pyridine is probably due to the unshared pair of electrons on the nitrogen atom. Addition of other compounds with an unshared pair of electrons on a nitrogen or an oxygen atom also Increased conversion In toluene supercritical gas extraction of a bituminous coal at 350^°C and a constant solvent density.     

THE EXTRACTION OF COALS WITH PYRIDINE AND TOLUENE AT 350°C

ABSTRACT

The extraction of three coals with mixtures of toluene and pyridine at 350^°C were compared. The conversion of both the bituminous and sub-bituminous coals Increased as the amount of pyridine in the mixture Increased up to ca 60% pyridine at a constant gas density of 0.64 g/ml. However, there was no Improvement in conversion for the brown coal when toluene was replaced with pyridine. The difference between pyridine and toluene conversion decreased as the gas density decreased. The high solvent efficiency of pyridine is probably due to the unshared pair of electrons on the nitrogen atom. Addition of other compounds with an unshared pair of electrons on a nitrogen or an oxygen atom also Increased conversion In toluene supercritical gas extraction of a bituminous coal at 350^°C and a constant solvent density.     

EXAMINATION OF THE HYDROLIQUEFACTION BEHAVIOR OF CHINESE LIGNITE

In order to examine the hydroliquefaction behaviour of Chinese lignites a series of bench scale experiments with four lignites, obtained from Inner Mongolia and province Yunnan, in comparison with three foreign lignites or brown coals were performed under three sets of constant reaction conditions. The results show that Chinese lignites in general are comparable with other lignites and conversion can be precaculatad from analytical data with reasonable accuracy. The H/C-ratio of the organic coal matter is an appropriate characterization parameter for the evaluation of the hydroliquefaction behaviour of lignites. Chinese lignites Shengli and Xun-dian reveal higher hydrogenation reactivity than the other five lignite samples. Under conditions used a maximum conversion of more than 80% with oil yields of 60% are obtained. The influence of temperature, H-transfer potential, catalyst and residence time on the product distribution were also investigated in detail. Each lignite has specific sensivities for these factors. The experimental results provide interesting informations for a perspective on hydroliquefaction of these lignites.     

SUPERCRITICAL FLUID EXTRACTION OF TURKISH LIGNITES AND OIL SHALE WITH TOLUENE MIXTURES

Abstract

Supercritical -Fluid extraction (SFE) of two Turkish lignites and oil shale with toluene mixtures were investigated. Experiments were performed in a batch autoclave at 623 K. Extracts recovered from SFE were fractionated into oils, asphaltenes and preasphal-tenes by solvent extraction.

The conversion of lignites decreased with increasing n-pentane content in the mixture. The extraction yield and the products (oils, AS, PAS) increased with increasing n-pentane content in its range below 15 %

The conversion and the extract yield obtained from Cöynük ail shale is higher with toluene mixture than toluene.     

EXAMINATION OF THE HYDROLIQUEFACTION BEHAVIOR OF CHINESE LIGNITE

ABSTRACT

In order to examine the hydroliquefaction behaviour of Chinese lignites a series of bench scale experiments with four lignites, obtained from Inner Mongolia and province Yunnan, in comparison with three foreign lignites or brown coals were performed under three sets of constant reaction conditions. The results show that Chinese lignites in general are comparable with other lignites and conversion can be precaculatad from analytical data with reasonable accuracy. The H/C-ratio of the organic coal matter is an appropriate characterization parameter for the evaluation of the hydroliquefaction behaviour of lignites. Chinese lignites Shengli and Xun-dian reveal higher hydrogenation reactivity than the other five lignite samples. Under conditions used a maximum conversion of more than 80% with oil yields of 60% are obtained. The influence of temperature, H-transfer potential, catalyst and residence time on the product distribution were also investigated in detail. Each lignite has specific sensivities for these factors. The experimental results provide interesting informations for a perspective on hydroliquefaction of these lignites.     

PROTON NMR IMAGING STUDIES OF COAL USING DEUTERATED SOLVENTS

Solvent transport into coal was studied by proton NMR imaging using pyridine - d₅ and acetone - d₆. Solvent swelling of Fushun bituminous coal was also observed by proton spin density images. From these NMR images, some information on the transport and swelling behavior of coal was obtained.     

COAL RANK AND TYPE VARIATION IN ROCK-EVAL ASSESSMENT OF NEW ZEALAND COALS

Rock-Eval and coal analytical data are compared for New Zealand coal samples ranging from peat to medium-volatile bituminous coal. Most are humic coals within the New Zealand coal band, which is representative of the Type III maturation series defined for kerogens. However, four were chosen as particularly high-hydrogen coal types. Relations between individual parameters — principally H/C, O/C, T_max, HI and OI — are generally similar to those of Espitalié et al. (1985, 1986), but important differences include a broader range of HI values in the peats and lignites, and a differentiation between maturation and coal-type effects in the relationship of HI to H/C. Correlations of the effects of maturation on HI, OI, T_max and vitrinite reflectance are made by the use of the independent Rank(S) scale of Suggate (1959).
Rank(S)/reflectance relations vary between well sequences. The Rank(S) scale is used to integrate biomarker data on hydrocarbon generation and expulsion. The oil zone ("oil window") corresponds to the range of bituminous coals, beginning at Rank(S) 10 (T_max425°C) and ending at Rank(S) 17 (T_max estimated at 550°C). Release of oil begins at or soon after Rank(S) 12.5 (T_max 435°C), and culminates in the range Rank(S) 14.5- 15.5 (T_max 460–480°C). For the Taranaki Basin, New Zealand, the results imply that a substantially greater volume of coal measures has been subject to oil generation and migration processes than previously thought.     

THERMAL REACTIVITIES OF SOME TURKISH LIGNITES

A DTA study has been made to investigate the thermal reactivities of five Turkish lignites (Elbistan, Ilgin, Karliova, Xangal, Yatagan) in an air atmosphere. The coal samples exhibited thermal reactivity at temperatures starting from 20 °C and continuing up to 671 °C. Endothermic peaks were observed at the lower end of the temperature range, the highest endothermic peak temperature being 146°C for Elbistan lignite. Exothermic peaks appeared at around 260, 360 and 600 °C. These temperatures are considered to signify the release and combustion of single benzene ring structures and combustion of condensed aromatic rings respectively. Corresponding stages are observed in the TGA traces. After correcting for differences in methodology, the overall heat effects measured by DTA are within greater than 90% of the calorific values of the coal samples determined by bomb calorimetry.     

载钼分子筛催化剂上C9+重芳烃轻质化的研究

 采用等体积浸渍法制备了不同分子筛负载的氧化钼催化剂,考察了它们在工业C9+重芳烃轻质化制苯、甲苯和二甲苯（BTX）反应中的催化活性,并采用X射线衍射、程序升温还原、N2吸附、吡啶吸附红外光谱和氨程序升温脱附等技术研究了分子筛载体对其所负载的氧化钼催化剂催化C9+重芳烃轻质化反应性能的影响。结果表明,分子筛载体对氧化钼催化剂催化C9+重芳烃轻质化反应性能的影响较大。分子筛孔道内与B酸位相互作用的Mo物种的存在极大地降低了反应的BTX选择性;催化剂上B酸的存在、酸量增加以及比表面积增大都可以提高反应的C9+芳烃转化率;一定范围内B酸的存在和酸量的增加均有利于苯、甲苯和二甲苯的生成,但酸量过多将促使二甲苯向苯和甲苯转化。MoO3/HMCM-56催化剂催化C9+重芳烃轻质化反应性能优异,在温度550 ℃、压力3.0 MPa、重芳烃质量空速（MHSV）3.62 h-1和氢/烃体积比1600的反应条件下,其BTX收率高达67.3%。     

PROTON NMR IMAGING STUDIES OF COAL USING DEUTERATED SOLVENTS

ABSTRACT

Solvent transport into coal was studied by proton NMR imaging using pyridine - d₅ and acetone - d₆. Solvent swelling of Fushun bituminous coal was also observed by proton spin density images. From these NMR images, some information on the transport and swelling behavior of coal was obtained.     

THERMAL REACTIVITIES OF SOME TURKISH LIGNITES

Abstract

A DTA study has been made to investigate the thermal reactivities of five Turkish lignites (Elbistan, Ilgin, Karliova, Xangal, Yatagan) in an air atmosphere. The coal samples exhibited thermal reactivity at temperatures starting from 20 °C and continuing up to 671 °C. Endothermic peaks were observed at the lower end of the temperature range, the highest endothermic peak temperature being 146°C for Elbistan lignite. Exothermic peaks appeared at around 260, 360 and 600 °C. These temperatures are considered to signify the release and combustion of single benzene ring structures and combustion of condensed aromatic rings respectively. Corresponding stages are observed in the TGA traces. After correcting for differences in methodology, the overall heat effects measured by DTA are within greater than 90% of the calorific values of the coal samples determined by bomb calorimetry.     

REACTIONS OF METHOXY-SUBSTITUTED AROMATIC COAL MOOELS IN SUPERCRITICAL SOLVENTS

Abstract

Reactions of α- and β-methoxy naphthalene and anisole in supercritical benzene and toluene were studied at 420 °C and 3.9-4.4 MPa pressure. The decomposition of these lower rank coal related model compounds in both solvents was found to obey the first order rate law. While naphthols were present in the reaction mixture of methoxy naphthalenes, phenol and cresoles were present in that of anisole. In addition to these products, diphenyl or dibenzyl was also present in the reaction mixture of supercritical benzene or toluene, respectively. The reactions between models and solvents might be explained by free radical and intermolecular rearrangement reaction pathways.     

CHEMICAL CHARACTERISTICS OF SUPERCRITICAL TOLUENE EXTRACTS FROM TWO TURKISH LIGNITES

Samples from two major deposits of Turkish lignites were subjected to supercritical toluene extraction at 325°C and 14.1 MPa in an autoclave. The resultant extracts were separated into pre-asphaltene, asphaltene, saturates, aromatics and resin fractions by column chromatography. The fractions were characterized by ¹H-NMR, ¹³C-NMR, IR. and elemental analysis in order to compare the chemical composition of extracis from the two coal samples. The results show that the extracts from the Tungbiiek (T-coal) deposits contain aliphatic constituent which is composed of mostly long chain unbranched alkyl compounds while the extracts from the Soma Mcrkeg (S-coal) deposits contain a significant amount of branched paraffinic compounds. The resin fractions from both samples were found to contain a significant amount of single ring aromatic compounds.     

芳烃烷基化反应性能对烷基化脱除汽油中硫化物过程的影响

以苯、甲苯和二甲苯作为芳烃模型化合物,考察了它们的烷基化反应性能,并将其对噻吩烷基化反应性能的影响进行了比较。实验结果表明,苯和二甲苯的烷基化反应性能比甲苯低得多,在反应温度60℃、压力1.5M Pa、质量空速3.0h-1、反应时间1h时,苯、二甲苯的转化率分别为8.88%和1.76%,甲苯转化率较高(达到43.21%);芳烃的烷基化反应性能均远低于噻吩的烷基化反应性能,在苯、甲苯和二甲苯存在时,噻吩转化率分别达到98.04%,87.68%,59.85%;在烯烃过量的情况下,苯和甲苯对噻吩烷基化反应的影响很小,而二甲苯的存在则可以在反应刚开始的较短时间内抑制噻吩的烷基化反应;芳烃烷基化反应性能影响烯烃烷基化反应性能的强弱顺序为:二甲苯>甲苯>苯。     

THIN-LAYER CHROMATOGRAPHY AS AN ALTERNATIVE TO SARA ANALYSIS OF COAL DERIVED LIQUIDS

SARA analysis has been applied to various coal derived liquids. Due to its tediousness, alternative procedures have been sought, capable of accomodating large numbers of samples. Procedures have been developed for separating toluene extracts into asphaltenes and oils and of pyridine extracts into preasphaltenes, asphaltenes and oils. In spite of a number of problems connected with absolute method calibration and with finding separation conditions giving similar results as solvent precipitation, thin layer chromatography with flame ionization detector (TLC/FID) has been shown to be a sensitive indicator of compositional changes of coal derived liquids as they depend on changes of experimental conditions of the liquefaction experiment.     

CHEMICAL CHARACTERISTICS OF SUPERCRITICAL TOLUENE EXTRACTS FROM TWO TURKISH LIGNITES

ABSTRACT

Samples from two major deposits of Turkish lignites were subjected to supercritical toluene extraction at 325°C and 14.1 MPa in an autoclave. The resultant extracts were separated into pre-asphaltene, asphaltene, saturates, aromatics and resin fractions by column chromatography. The fractions were characterized by ¹H-NMR, ¹³C-NMR, IR. and elemental analysis in order to compare the chemical composition of extracis from the two coal samples. The results show that the extracts from the Tungbiiek (T-coal) deposits contain aliphatic constituent which is composed of mostly long chain unbranched alkyl compounds while the extracts from the Soma Mcrkeg (S-coal) deposits contain a significant amount of branched paraffinic compounds. The resin fractions from both samples were found to contain a significant amount of single ring aromatic compounds.     

THIN-LAYER CHROMATOGRAPHY AS AN ALTERNATIVE TO SARA ANALYSIS OF COAL DERIVED LIQUIDS

ABSTRACT

SARA analysis has been applied to various coal derived liquids. Due to its tediousness, alternative procedures have been sought, capable of accomodating large numbers of samples. Procedures have been developed for separating toluene extracts into asphaltenes and oils and of pyridine extracts into preasphaltenes, asphaltenes and oils. In spite of a number of problems connected with absolute method calibration and with finding separation conditions giving similar results as solvent precipitation, thin layer chromatography with flame ionization detector (TLC/FID) has been shown to be a sensitive indicator of compositional changes of coal derived liquids as they depend on changes of experimental conditions of the liquefaction experiment.     

煤成气轻烃组分和碳同位素分布特征与天然气勘探

采用烃源岩热模拟实验和轻烃单体烃碳同位素分析方法,对煤热解轻烃生成模式及煤系烃源岩热解轻烃碳同位素组成特征的研究表明,在成熟度 R_o 值为1.1%～1.7%时,煤热解轻烃大量生成;当 R_o 值大于1.7%时,以芳烃生成为主。煤热解轻烃中苯和甲苯碳同位素均较重,苯的碳同位素值平均为－22.2‰,甲苯的碳同位素值平均为－22.1‰,与母源有机质干酪根碳同位素值非常接近,具有良好的碳同位素继承效应。对塔里木、准噶尔、鄂尔多斯、四川和松辽等盆地煤成气轻烃组分和碳同位素分析表明,煤成气具有甲基环己烷分布优势,在甲基环己烷、二甲基环戊烷和正庚烷相对组成中,173个煤成气样品中有92%的样品甲基环己烷相对含量大于50%;煤成气轻烃中苯、甲苯、环己烷和甲基环己烷碳同位素重,碳同位素值平均分别为－20.9‰、－20.4‰、－21.9‰和－22.0‰。应用轻烃组成变化对苏里格煤成气大气田天然气运移方向进行的研究表明,在气藏形成时期,天然气运移方向为由南向北。