in the 1970 s, regulations in some counries forced usersof heavy residue to limit pollutant emissions at industrial sites, also forced producers to up grade their heavy products for export and domestic use. for this reason iran as a producer, exporter and consumer has to develop mew upgrading processes.the most common processes for upgrading heavy oil are catalytic processes, but existence of h...

The d iscovery o f e l e c t r o n s p i n resonance ( e s r ) absorp t ion i n n a t u r a l carbons by Uebersfeld (1) and Ingram ( 2 ) prompted a number of i n v e s t i g a t o r s to apply t h e techn ique t o coa l and materials der ived from c o a l . A t least t h r e e e x c e l l e n t review a r t i c l e s descr ib ing t h e e a r l y esr s t u d i e s o f c o a l s have been publish...

We designed and studied hydrocarbon model compounds by high-resolution noncontact atomic force microscopy. In addition to planar polycyclic aromatic moieties, these novel model compounds feature linear alkyl and cycloaliphatic motifs that exist in most hydrocarbon resources - particularly in petroleum asphaltenes and other petroleum fractions - or in lipids in biological samples. We demonstrate...

In this work the likelihood of asphaltene deposition problems during dynamic displacement of oil by natural gas in unconsolidated porous media is experimentally inspected. The two different rock materials, limestone and sandstone, are used as a representative of porous media. Dynamic flow experiments indicate that the increase of natural gas injection increases asphaltene deposition in the unco...

Asphaltenes are known to cause problems related flocculation, precipitation, and plugging, either in the formation, production lines, processing equipment. Different models have been proposed predict thermodynamic conditions under which asphaltenes precipitate over past years. This work analyses performance of various on their capability match literature experimental data precipitated asphalten...

The conditions of petroleum extraction may allow asphaltenes to precipitate, causing deposition that clogs wells, pipes and equipment, consequently reducing productivity. In this work, the solubility parameters precipitation onset polar fractions heavy crudes from Brazilian fields were estimated using a simplified system n-heptane/toluene mixtures. Asphaltenes extracted by two different methods...