DEVELOPMENT OF TECHNOLOGICAL SOLUTIONS TO REMOVE POLYMER DEPOSITS FROM THE INTERNAL SURFACE OF STYRENE PRODUCTION PIPELINES

Abstract

Styrene, methylstyrenes and other substituted vinylbenzenes are thermally unstable compounds and spontaneously polymerize already at room temperature during storage and transportation. As the temperature rises, the rate of spontaneous polymerization sharply increases. Uncontrolled polymerization that occurs during the process of styrene recovery from the products of ethylbenzene dehydrogenation at the rectification stage often leads to clogging of equipment with polymer. This phenomenon can cause significant economic damage in the event of unforeseen shutdowns or unstable operation of process equipment.The article considers a method for removing polymer deposits from the inner surface of styrene production pipelines. The data of laboratory analyzes of polymer deposits are given: the solubility of the latter in a number of organic solvents of the aromatic series was studied, the ash content was determined, the presence of a significant amount of iron oxides in the ash was shown, the presence of aluminum was qualitatively confirmed; the methods of thermogravimetric analysis and differential scanning calorimetry proved the polymeric nature of the deposits; IR spectroscopy showed the identity of the structure of deposits and polystyrene. Based on laboratory studies, the composition of the washing liquid was selected, which includes toluene and a surfactant. The tests of the proposed washing mixture in the conditions of the operating plant for the production of styrene showed its high efficiency.