کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6476634 1425390 2017 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Behavior of radicals during solvent extraction of three low rank bituminous coals
ترجمه فارسی عنوان
رفتار رادیکالها در حین استخراج حلال از سه ذغال سنگ بتمنس با درجه پایین
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


- Change in radical concentration during solvent extraction of 3 coals is studied.
- Temperature and solvent type affect radical concentration during extraction.
- Radical concentration decreases in some solvents due to coupling of free radicals.
- Radicals generate at high temperatures or in NMP due to cleavage of weak bonds.
- Change in radical is related with the properties of solvents.

Solvent extraction of coals has been practiced extensively for various purposes including the determination of coal structure. It is generally assumed that the extraction is mainly a physical process involving little change in covalent bonds. But different opinions were reported. This work studies the behavior of radicals during extraction of 3 low rank bituminous coals using 5 solvents, including hexane, toluene, tetrahydrofuran (THF), 1,2,3,4-tetrahydronaphthalene (THN), and N-methyl-2-pyrrolidinone (NMP), using electron spin resonance (ESR). The extractions are carried out at temperatures from the ambient temperature to temperatures somewhat higher than the boiling points of the solvents, as well as under ultrasound. It is found that the radical concentration of the coals changes during the extraction, and the change is influenced by temperature and varies with the solvent. The decrease in radical concentration in most solvents at temperatures lower than their boiling points is attribute to coupling of free radicals dissolved from the coals, while the increase in radical concentration at high temperatures and in NMP is attributed to the cleavage of weak bonds in coals by the solvents.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Fuel Processing Technology - Volume 156, February 2017, Pages 221-227
نویسندگان
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