Nitrogen in oil shale and shale oil. VI. Acid washing of crude shale oil

The presence of organic nitrogen compounds has been found to have an important bearing on the behaviour of an oil towards catalytic cracking or hydrogenation.For example, Gordon (1) reports that the nitrogen content of a coal oil for hydrogenation must be kept below five parts per million in order to maintain a high activity for the tungsten sulphide hydrogenation catalyst.