Abstract
The technologies for extracting an iron-containing catalyst from process streams of direct chlorination of ethylene, as well as methods for the disposal of organochlorine wastes from vinyl chloride production, are considered. Problems arising from thermal waste disposal necessitate studies on the extraction of iron compounds from organochlorine by-products of the ethylene chlorination process. X-ray fluorescence analysis found that the composition of the burning sludge, as the main elements, includes iron – 33.52% and chlorine – 32.69%. The extraction of iron compounds with aqueous and aqueous acidic media under mechanical stirring is studied. It is shown that the addition of hydrochloric acid to the solution does not contribute to an increase in the degree of extraction of iron compounds. It is found that an increase in the duration of extraction and the temperature of this process provides a degree of extraction of iron compounds of more than 80%. The process of separation of an aqueous-organic emulsion, which is formed during extraction, by sedimentation, filtration and centrifugation, is investigated. It is found that at a temperature of about 80 °C there is an effective and rapid separation of the aqueous and organic phases as a result of sedimentation. Based on the obtained experimental results of the extraction study, a functional scheme for the extraction of an iron-containing catalyst is proposed, as well as ways to solve technological and environmental problems that arise during the combustion of organochlorine wastes from vinyl chloride production. The scheme provides for the use of the heat of hot organochlorine wastes for the extraction of iron compounds with industrial water. In addition, the use of the heat of the gases generated during the combustion of organochlorine wastes is provided for heating air, which low-boiling components from these wastes are blown off. In the future, this air is used to burn organochlorine wastes purified from iron compounds
Highlights
The production and consumption of vinyl chloride (VC) in the world is about 30 million tons [1]
It has been established that one of the main components of the solid residue resulting from the combustion of organochlorine wastes is sparingly soluble iron compounds
They are formed due to the high-temperature conversion of iron (III) chloride, which is used as a catalyst in the chlorination of ethylene
Summary
The production and consumption of vinyl chloride (VC) in the world is about 30 million tons [1]. The main part of VC (98–99 %) is used for the production of polyvinyl chloride (PVC), and approximately 1 % VC is used in the preparation of copolymers with vinyl acetate and other monomers. VC production consists of two main stages: 1) obtaining dichloroethane (DCE) by direct and oxidative chlorination of ethylene using iron (III) chloride and copper (II) chloride as catalysts; 2) high-temperature cleavage of hydrogen chloride from DCE with the formation of VC. In the system of distillation columns, raw DCE is dehydrated and cleaned of “light” and “heavy” organochlorine by-products called organochlorine waste Thermal disposal of distillation bottoms is an important stage for environmental protection in the treatment of wastes from VC production. During the thermal destruction of “light” and “heavy” organochlorine by-products, hydrochloric acid is regenerated and thermal energy is utilized by producing process water vapor using a steam generator
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