EFFECT OF MOISTURE IN COAL ON ITS ORGANIC SULFUR EXTRACTABILITY

Abstract

The extent of organic sulfur removed by the perchloroethylene desulfurization process depends upon several factors including the type of coal, the amount of catalyst present in it, and the temperature of organosulfiir extraction. Moisture in coal also plays a very important role in this extraction process. In this paper, the role played by moisture and its subsequent effect on the process efficiency has been investigated. It has been found that the moisture in coal affects the extraction process in two ways. Firstly, in presence of water, the temperature of the operation is reduced. This affects the organosulfiir extraction efficiency adversely. Secondly, the naturally available catalytic ingredients in coal, essential for the organosulfiir extraction, are soluble in water. Therefore, in presence of water, the catalytic potency of these catalytic species is lost, and thus reducing the organosulfiir extractability. The data presented in this paper are also important from the point of view of process development, because it has been experimentally established that the moisture content in coal has to be sufficiently reduced in order to improve the overall process efficiency.     

STUDY ON CHEMICAL STABILITY OF ORGANIC SULFUR IN COAL AND ITS STRUCTURE*

In this paper, two high-sulfur coals were selected from Yazhou and Donglin mines of China. Inorganic sulfur was completely removed first, then the tested samples were experimented under various conditions: hydrolysis, oxidation, reduction, and supercritical extraction with methanol. The change in organic sulfur was investigated. It was found that approximately 40-60% organic sulfur in coal was released at the temperature of 350°C. The removed organic sulfur was thioalcohol and thioether, while the remaining part in coal was thiophenic sulfur.     

STUDY ON CHEMICAL STABILITY OF ORGANIC SULFUR IN COAL AND ITS STRUCTURE*

ABSTRACT

In this paper, two high-sulfur coals were selected from Yazhou and Donglin mines of China. Inorganic sulfur was completely removed first, then the tested samples were experimented under various conditions: hydrolysis, oxidation, reduction, and supercritical extraction with methanol. The change in organic sulfur was investigated. It was found that approximately 40-60% organic sulfur in coal was released at the temperature of 350°C. The removed organic sulfur was thioalcohol and thioether, while the remaining part in coal was thiophenic sulfur.     

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.     

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 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.     

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

Abstract

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

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 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     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY TRICHLOROETHANE EXTRACTION

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     

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.     

渣油中硫和硫类型分布对热转化产物中硫分布的影响

考察了热转化反应条件对胜利和孤岛渣油热转化产品中硫分布的影响。在研究原料中硫、硫醚硫、噻酚硫分布和残分布的基础上,探讨了原料硫分布与热转化产品中硫分布的关系。     

烷基化原料硫含量对选择加氢催化剂的影响

在实验室进行了催化剂评价试验,考察了烷基化原料中不同硫化物种类及含量对选择加氢催化剂的影响,结果表明,QSH-01催化剂在保持良好的加氢活性、选择性的同时,具有较为优良的抗硫性能。     

苯乙烯对不溶性硫磺的萃取效果研究

研究在不同时间、温度、液固比条件下苯乙烯对不溶性硫磺的萃取效率。在对普通硫磺溶解性研究实验中,相同温度下,苯乙烯对硫磺的溶解度大于甲苯和四氯乙烯。利用专业实验设计软件Design Expert安排实验,结果表明,在温度77℃、时间10min、液固比27时,提纯后的不溶性硫磺质量分数最大可达94.2%,萃取效率最大值91.1%,得到质量分数大于90%的高品位不溶性硫磺。     

催化剂上沉积钒氧化数对降低FCC汽油中硫含量的影响

过滤金属化合物与硫化物相互作用的分子模拟研究结果表明，低氧化数钒的氧化物有利于促进硫化物的转化。然而，工业运转中催化剂在进入反应器前已经历氧化再生，沉积于其上的钒处于高氧化数状态，为此提出了强化降低催化剂上沉积钒氧化数的“择效活化”方法。电子顺磁共振(ESR)结果表明，通过择效活化处理，催化剂上沉积钒的氧化数下降。重油微反评价结果表明，高钒活化剂进一步表现出明显优于高钒再生剂的降硫作用；高钒人工污染再生剂具有强于未污染剂的降硫作用，并且经择效活化后，高钒污染活化剂进一步表现出明显优于高钒污染再生剂的降硫作用，评价实验证实了分子模拟计算的结果。     

水解工艺对腈纶吸湿性能的影响

对制备吸湿腈纶的水解工艺进行了研究。结果表明,水解剂、水解温度、Na OH质量分数都对腈纶的吸湿性有影响。水解时间越长,水解温度越高,Na OH质量分数越大,腈纶的吸湿性越大,但其质量损失率也逐步增大。腈纶水解的适宜条件:氢氧化钠的质量分数20%,水解温度90℃,水解时间60~90 min。     

THE VARIATION OF SULFUR FORMS IN SUPERCRITICAL DESULFURIZATION OF COAL WITH ETHANOL

Using Mossbauer and X-ray Photoelectron Spectroscopy ( XPS) techniques the sulfur forms in solid products obtained at different reaction were analyzed. The results show that: during supercritical desulfurization the pyritic sulfur is removed as following process: FeS₂ -FeS+ Fe_1-x S, the transformation amounts and the value of x are dependent on reaction conditions, especially on temperature. The conversion of pyrite is very little at 275° C. Pyrrhotite ( Fe_1-xS) is Fes_1.101 at 275° C and Fe_1.085 at 450° C. Among the organic sulfur groups PhSH. Ph₂ S and thiolane are easily removed; Ph ₂ SO is more difficult to be removed, its removal may be realized by increasing temperature and adding some water into ethanol; thiophene is most difficult to be removed, its removal needs high reaction temperature     

THE VARIATION OF SULFUR FORMS IN SUPERCRITICAL DESULFURIZATION OF COAL WITH ETHANOL

ABSTRACT

Using Mossbauer and X-ray Photoelectron Spectroscopy ( XPS) techniques the sulfur forms in solid products obtained at different reaction were analyzed. The results show that: during supercritical desulfurization the pyritic sulfur is removed as following process: FeS₂ -FeS+ Fe_1-x S, the transformation amounts and the value of x are dependent on reaction conditions, especially on temperature. The conversion of pyrite is very little at 275° C. Pyrrhotite ( Fe_1-xS) is Fes_1.101 at 275° C and Fe_1.085 at 450° C. Among the organic sulfur groups PhSH. Ph₂ S and thiolane are easily removed; Ph ₂ SO is more difficult to be removed, its removal may be realized by increasing temperature and adding some water into ethanol; thiophene is most difficult to be removed, its removal needs high reaction temperature