EFFECT OF FILTRATION TEMPERATURE ON ORGANIC SULFUR REMOVAL FROM COAL BY PERCHLOROETHYLENE COAL CLEANING PROCESS

The perchloroethylene extraction desulfurization process removes the organic sulfur in coal via a hybrid mechanism of solvent extraction and chemical reaction. The nature and extent of the reaction is controlled by the extraction time and temperature of operation. Although the extraction temperature is kept identical for all types of coals (120°C), the organosulfur extraction time still depends upon the type of coal. If the reaction mixture is left too long in the extraction environment, the intermediate labile sulfur released by the reaction forms cross-links with the organic matter in the macromolecule of coal. This is detrimental to the process efficiency. Constant temperature has to be maintained throughout the extraction, till coal is separated from the solvent. If not, the extracted labile sulfur re-enters the coal macromolecule to form inter-penetrating polymer networks with the organic matter in coal. In this paper, it has been established that the time required for separation and isothermality of the process are crucial to maintain the reaction progressing toward sulfur and organic sulfur liberation from the macromolecule. The data presented in this paper are important from the viewpoint of process development, because the process mandates the separation of coal and solvent at the operating temperature.     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY PERCHLOROETHYLENE EXTRACTION

ABSTRACT

Desulfurization of coal involves the removal of both the inorganic and organic forms of sulfur. Several physical methods are available for the removal of inorganic sulfur which is normally represented by pyritic and sulfatic sulfur. Removal of organic sulfur requires the use of chemical cleaning methods. This paper presents the results of an organic sulfur removal technique which employs an organic solvent. This desulfurization technique is selective enough to reject organic sulfur without significantly reducing the calorific value of the treated coal. The sulfur containing organic species in the liquid product from the desulfurization procedure have been completely characterized using GC/MS techniques. These results provide further insights into the nature of the sulfur forms in the parent coal as well as the metamorphism of sulfur species in the coal, and the selective nature of the desulfurization process.     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY PERCHLOROETHYLENE EXTRACTION

Desulfurization of coal involves the removal of both the inorganic and organic forms of sulfur. Several physical methods are available for the removal of inorganic sulfur which is normally represented by pyritic and sulfatic sulfur. Removal of organic sulfur requires the use of chemical cleaning methods. This paper presents the results of an organic sulfur removal technique which employs an organic solvent. This desulfurization technique is selective enough to reject organic sulfur without significantly reducing the calorific value of the treated coal. The sulfur containing organic species in the liquid product from the desulfurization procedure have been completely characterized using GC/MS techniques. These results provide further insights into the nature of the sulfur forms in the parent coal as well as the metamorphism of sulfur species in the coal, and the selective nature of the desulfurization process.     

EFFECT OF PYRITIC SULFUR AND MINERAL HATTER ON ORGANIC SULFUR REMOVAL FROM COAL

The perchloroethylene coal cleaning process uses perchloroethylene as the solvent to remove both organic and inorganic forms of sulfur without any significant loss to its calorific value. The process removes these forms of sulfur in two sequential unit steps. The objective of this investigation was to determine the exact sequence of operations in the Process. Hence, organosulfur was removed before and after depyriting and demineralizing the coal. The extent of total sulfur as well as organic sulfur removal were compared in both cases. It was found that the desulfurization is more efficient when organosulfur is extracted before pyritic sulfur and not vice versa, in the sequential removal of organic and inorganic forms of sulfur. The data presented in this paper reestablishes a fact that the mineral matter content in coal is quintessential to its organosulfur extractability.     

EFFECT OF PYRITIC SULFUR AND MINERAL HATTER ON ORGANIC SULFUR REMOVAL FROM COAL

Abstract

The perchloroethylene coal cleaning process uses perchloroethylene as the solvent to remove both organic and inorganic forms of sulfur without any significant loss to its calorific value. The process removes these forms of sulfur in two sequential unit steps. The objective of this investigation was to determine the exact sequence of operations in the Process. Hence, organosulfur was removed before and after depyriting and demineralizing the coal. The extent of total sulfur as well as organic sulfur removal were compared in both cases. It was found that the desulfurization is more efficient when organosulfur is extracted before pyritic sulfur and not vice versa, in the sequential removal of organic and inorganic forms of sulfur. The data presented in this paper reestablishes a fact that the mineral matter content in coal is quintessential to its organosulfur extractability.     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY TRICHLOROETHANE EXTRACTION

ABSTRACT

Desulfurization of coal involves removal of both organic and inorganic forms of sulfur. In this paper, the process feasibility of organic desulfurization of coal using 1,1,1-trichloroethane (TCA) as the solvent, is established. Sulfur solubility curve in tnchloroethane was obtained. The process conditions of this novel process were critically assessed. From the solubility curve it was concluded that the process should be carried out at or near the normal boiling point of the solvent. Comparisons between the TCA extraction and the perchloroeihylene (PCE) process have been presented. Since the boiling point of tricbloroethane is quite low, the process conditions are very mild in comparision to the PCE process. It was found that the TCA process is capable of removing organosulfur from coal more selectively than the PCE process. The sulfur containing organic species in the extract obtained from     

凝析气藏气液两相渗流的高速流动效应研究

为了研究高速流动效应对凝析气藏渗流特征的影响，在凝析气藏不稳定渗流数学模型中引入非达西效应和毛细管数效应对相对渗透率的修正模型，并进行数值求解。研究表明，在较低的凝析油饱和度时，毛细管数效应起主要作用，对凝析油产生速度剥离效应，提高气相相对渗透率，而在较高的凝析油饱和度时，非达西效应对气相相对渗透率的负作用更加明显；油相相对渗透率对非达西效应不敏感，但随毛细管数增加而增加。考虑高速流动效应的储层径向上凝析油饱和度明显低于不考虑高速流动效应的情况，随日产气量的增加，近井带的毛细管数效应逐渐增强，远离近井带，非达西效应逐渐超过毛细管数效应，使得最大反凝析液饱和度区不断沿径向向外推进。     

CHARACTERIZATION OF COAL CHARS FROM A FLASH PYROLYSIS PROCESS BY CROSS POLARIZATION/MAGIC ANGLE SPINNING 13C NMR

ABSTRACT

Chars from the Illinois Springfield (No. 5) Coal are prepared by flash pyrolysis at progressively higher charring temperatures. The results of a study of these chars by ¹³C NMR with CP/MAS indicate that the initial stage of heating (300^°C) produces a char with aromatic carbon fraction (f_ar) of 68%, and successive heating gives chars with f_ar of 70% (400^°C), 73% (500^°C), 89% (600^°C), 95% (700^°C), and 96% (800^°C). However, the actual amount of aromatic and aliphatic carbon in the char can be calculated by using the NMR measurements, the organic carbon content of the char, and the weight of the char. The calculated values show that the amount of aromatic carbon in char remains relatively constant at each temperature, but the amount of aliphatic carbon in char is reduced during higher temperature charring. At 600^°C, both a large reduction of the aliphatic carbon content and a maximum weight loss occur. Evidently, the aliphatic-bond carbon in coal is the principal source of volatiles derived from coal. The apparent increase in aromaticity (f_ar) of the char heated to progressively higher temperatures is due to the loss of aliphatic-bond moieties and reduction in volume of materials.     

弱凝胶对油水相对渗透率的影响

在凝胶处理后,油/水相相对渗透率均大幅度下降,可动饱和度范围明显缩小,弱凝胶的易屈服性导致渗透率随流速增加而上升.凝胶处理使油/水相渗透率产生不均衡减少是由于油在通过凝胶时部分残余油占据的孔隙形成了新的流动通道;但水驱时,由于油/水界面张力较高,残余油形成的大部分通道关闭.所以,在同样的驱动力下油/水通过凝胶处理后的含油地层时,油相渗透率高于水相渗透率.     

RECOVERY OF ORGANIC MATERIAL BY SUPERCRITICAL TOLUENE FROM TURKISH GOYNOK OIL SHALE 1. IDENTIFICATION OF THE MINERALS AND THEIR EFFECT ON THE RECOVERY OF OKGANIC MATERIAL

ABSTRACT

Effect of the mineral matrix on the recovery of organic material by supercritical toluene extraction from Turkish Göynük oil shale was investigated. Samples were prepared by successive demineralization procedures to study the interaction of different mineral groups during the supercritical interaction. Extraction experiments were done in a stainless steel autoclave of 75 ml capacity at 350^°C for 60 minutes. Effect of the toluene/kerogon ratio and reaction time on the recovery of organic material was studied. Infrared spectra of the spent material uere measured to determine the structure of the organic material remaining after the supercritical treatment. The inorganic matrix of the shale was composed of calcite, silicate and pyrite minerals. Recovery of the organic material in the supercritical extraction experiments increased from 42% to 98% as the toluene/kerogen ratio was increased from 23.5 to 275. The extent of depolymerization seemed to be dependent on the to!uene/kerogen ratio and this suggested the possible cleavage of bonds due to solvent attack. Dissolution of carbonates and. Silicates decreased the organic material recovery extensively. The organic material recovered from the carbonate–free shale were about 50% lower than the organic material recovered from the original shale. Removal of pyrites did not affect the recovery of the organic matter. Percentage of the organic material recovered increased when CaCO₃ Or SiO₂ was added to kerogen and silicate free shale. These findings indicated that carbonate and silicate ninerals originally present in the shale might increase the organic matter recovery by supercritical toluene extraction. The raise of the toluene/kerogen ratio yielded more polar organic material. The aliphatic content of the recovered material was not affected by an increase in the toluene/kerogen ratio.