Asphaltene hydroconversion

Martmez, M.T., Benito, A.M., Callejas, M.A. 1997. Kinetics of asphaltene hydroconversion 1. Thermal hydrocracking of a coal residue. Fuel 76(10) 899-905. 

Previous reference has been made to the benefits of removing an asphaltene fraction from the feedstock prior to hydroprocessing and prior to the application of a hydroconversion process. Chemically, this approach may be sound but an economic benefit must also be realized. This will be determined on a case by case basis. 

The major goal of hydroconversion is the cracking of residua with desulfurization, metal removal, denitrogenation, and asphaltene conversion. The residuum hydroconversion process offers production of kerosene and gas oil, and production of feedstocks for hydrocracking, fluid catalytic cracking, and petrochemical applications. 

Our main purpose for developing residual hydroconversion catalyst is the upgrading of petroleum residue, decomposition of asphaltenic components and hydrocracking of hydrocarbons to obtain useful middle distillates from petroleum residue. Through extensive studies on HDS catalysts, hydroconversion was determined to be entirely dependent on reaction temperature [2]. On the other hand, coking and metal deposition onto catalyst were reported to occur under such high temperatures as to decrease catalyst activity and shorten catalyst life [5,6,7,8]. 

The thermal hydroconversion of Cold Lake asphaltenes was studied initially to provide a basis for evaluation of catalytic effectiveness in subsequent work. Series of thermal runs were made at 335°C, 365°C and 400°C and the reaction products were separated as described previously. Several kinetic models were tried, but after examining the variability of our data, we decided on the simple first-order asphaltene decomposition model shown below ... 

Figure 1. Thermal hydroconversion of Cold Lake asphaltenes at 400°C and 6 MPa H2 asphaltenes ( A) maltenes (O) coke ) model (-).

Figure 3. Arrhenius plot for hydroconversion of Cold Lake asphaltenes 200 ppm molybdenum (A) thermal (0).

Gauthier T, Danial-Fortain P, Merdrignac I, Guibard I, Quoineaud A-A. Studies on the evolution of asphaltene structure during hydroconversion of petroleum residues. Catal. Today 2008 130 429-438. 

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