Cold Lake asphaltenes crude

ESR Parameters for Cold Lake Asphaltenes Parameter Crude Asphaltenes Residuum Asphaltenes... 

Figure 2. Hydroconversion of Cold Lake crude asphaltenes with 200 ppm molybdenum at 400°C and 6 MPa Ht asphaltenes (A) maltenes (%) coke (JC model (-).

These heavy oils already contain large percentages of refractory materials such as asphaltenes, and it would be highly undesirable to increase the amount or degrade the quality of these components. We have, therefore, investigated the effect of heat treatment during distillation on the quantity and physical and chemical properties of asphaltenes. Cold Lake crude was chosen for this study since it is known to be a thermally sensitive material. 

Preparation of Asphaltenes. Asphaltenes were obtained by n-heptane precipitation from either Cold Lake crude or vacuum residuum using typical deasphaltening procedures. (i.e. One part of residuum was refluxed for one hour with 10 parts of heptane. 

To provide raw material for this comparative study of untreated and heat-treated oils, asphaltenes from Cold Lake crude (crude asphaltenes) and from Cold Lake vacuum residuum (residuum asphaltenes) were prepared by n-heptane precipitation as described in the Experimental section. The Cold Lake residuum fraction was prepared by Imperial Oil Enterprises, Ltd. at Sarnia, Ontario, Canada. The distillation history of this bottoms fraction indicates that the pot material was subjected to temperatures as high as 314-318°C during atmospheric and vacuum distillation. The length of time at 300°C or higher was about two hours. This is well in excess of what would be experienced in a pipestill and should have provided ample time for any decomposition. It should be noted, however, that since it was possible to maintain the system vacuum at 0.35 mm, the maximum temperature experienced by the residuum was not quite as high as it might be during refinery distillation (e.g. ca 350°C). 

Asphaltene Yields from Cold Lake Crude and Residuum Source % Asphaltenes (On Crude)... 

Figure 3. IR spectrum of Cold Lake crude asphaltenes...

The characteristics of Cold Lake crude and residuum asphaltenes have been compared by a number of instrumental and physical techniques. The asphaltenes were essentially identical in quality... 

Since the Cold Lake crude used in this investigation has been exposed to the temperature of the pressuized steam used in the oil production, one cannot be certain that some thermal changes had not already occurred in the crude oil. To study this possibility the properties of cold bailed (i.e. recovered without steam injection) Cold Lake crude asphaltenes are being investigated by many of these same techniques and will be described in a future report. 

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