OBTAINING DICARBOXYLIC ACIDS WITH INCREASED ENERGY REGENERATION Russian patent published in 2015 - IPC C07C51/265 C07C63/26 C07C63/15 C07C63/24 C07C63/16 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of obtaining aromatic dicarboxylic acid, with the claimed method including the following stages: (a) oxidation of an aromatic compound in at least one oxidation device with thus obtaining oxidation device discharge gases and the oxidation device suspension, which includes aromatic dicarboxylic acid, with the said oxidation device discharge gases containing at least 12.4 kilograms of steam per a kilogram of the said aromatic compound, supplied into the oxidation device; (b) extraction of hydrocarbon compounds from the said oxidation device discharge gases in the system of a solvent regeneration with thus obtaining poor in hydrocarbons discharge gases, containing at least 3 kilograms of water steam per a kilogram of the said aromatic compound, supplied into the oxidation device; and (c) passing at least a part of the said poor in hydrocarbons discharge gases through at least one turbo-expander to generate work in this way, and the said poor in hydrocarbons discharge gases, supplied into the said turbo-expander, include at least 3 kilograms of water steam per a kilogram of the said aromatic compound, supplied into the said oxidation device. Application of the discharge gases results in an increased shaft power, greater than the required one for driving the main air compressor, even with preferable, relatively low temperatures of oxidation. At the same time, an amount of sewage waters, greater than water obtained as a by-product of xylol oxidation, is held in a steam form and processed together with environment pollutants in the discharge gases in a device for the self-supported (self-feeding) gas phase thermo-oxidative degradation.

EFFECT: invention provides an improved energy content and extraction of shaft power from the discharge gases in reactions of xylol oxidation, simultaneously reducing to the minimum expenditures for sewage water processing.

29 cl, 1 dwg