US 6,288,289 B1 · Integrated effluent treatment process for nitroaromatic manufacture

Abstract

An integrated process for treating alkaline wash water effluent from nitroaromatic manufacture, principally containing nitro-hydroxy-aromatic compounds is described. The integrated process concentrates the alkaline wash water to recover chemicals and water prior to treating the concentrate through supercritical water oxidation. The supercritical water oxidation step consists of treating the concentrate in the presence of an oxygen source at conditions, which are supercritical for water to cause a substantial portion of the organic component of the concentrate to oxidize. The product effluent includes a gaseous component and a clean water component, and in the event that insoluble ash is formed, an ash component. The new integrated process results in reduced chemical and water consumption compared to existing processes. In addition, the treated wash water effluent can be recycled to process or directly discharged.

Claims16

Dependent claims

A method of integrating nitroaromatic washing with supercritical water oxidation treatment of the effluent, comprising the steps of:

(a) washing of the crude nitroaromatic product from a nitroaromatic synthesis process, whereby the synthesis occurs in a mixture of sulfuric and nitric acid, with acidic water to remove the majority of the mineral acids, followed by separation of the nitroaromatic from the acidic water;
(b) washing of the nitroaromatic product from the acidic washing step in alkaline water to remove substantially all of the nitro-hydroxy-aromatic byproducts, followed by separation of the nitroaromatic from the aqueous effluent;
(c) concentration of the aqueous effluent from the alkaline washing step by removal of water and volatile components to near or above the nitro-hydroxy-aromatic solubility;
(d) recycle of water and volatile components removed in the effluent concentrator to the alkaline washing step to recover water and product;
(e) treatment of the concentrated nitro-hydroxy-aromatic effluent in the presence of an oxygen source at conditions supercritical for water, to thereby oxidize a substantial portion of the nitro-hydroxy-aromatic and other organic compounds.

2 more elements

Dependencies are inferred from the claim text.

Integrated effluent treatment process for nitroaromatic manufacture

Life of this patent

Integrated effluent treatment process for nitroaromatic manufacture

Life of this patent

Abstract

Claims16