Use of Germanium Organic Compounds Labelled with Germanium-77 to Investigate the Behaviour of Petroleum Products in Refining Installations

The labelled organic compounds so far used to investigate the behaviour of petroleum products in refining equipment cannot always be used because their chemical and physical properties differ so markedly from those of the products. Comparison of the chemical, physical and radiochemical properties of the various types of labelled organic compound leads to the conclusion that the most suitable ones for isotope studies in the petroleum- refining industry are germanium-organic compounds labelled with 77Ge, since they have chemical and physical properties very close to those of hydrocarbons, and their radiochemical characteristics are very suitable for industrial isotope investigations. The authors have therefore developed methods of synthesizing various germanium-organic compounds which are then subjected to neutron activation to produce the corresponding compounds labelled with 77Ge. Germanium-organic compounds were subjected, in amounts of about 10-20 g, to activation in a neutron flux of 1013 n/cm2 s for 1-5 h depending on the activity required for the investigations. The tests on industrial equipment were normally carried out 12-15 h after activation. The recording apparatus was placed at suitable points on the outer walls of the equipment. As the radioactive substances passed the measuring point the apparatus normally gave maximum readings exceeding the background by factors of several tens to several hundreds. Tetraethyl-germanium labelled with 77Ge was used to determine the reflux circulation time and the time taken for the petroleum fraction to evaporate on the corresponding plates of a distillation column operating at normal pressure with a productivity of 400 tons per day. Tetra-n-amyl germanium labelled with 77Ge was used to determine the linear rate of movement of petroleum in the separate sections of the oven used to heat it before feeding to the distillation column. The capacity of this oven was 400 tons per hour. These investigations made it possible to determine genuine technological indices, and also showed conclusively that germanium-organic compounds labelled with 77Ge lend themselves very well to technological studies in petroleum refining. Good results have been obtained and work is being continued to investigate the processes occurring in the separate units of the refining equipment. (author)