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MONITORING ORGANIC COMPOUNDS IN THE WASTE WATER OF MONONITROBENZENE PRODUCTION

IP.com Disclosure Number: IPCOM000206136D
Publication Date: 2011-Apr-14
Document File: 2 page(s) / 8K

Publishing Venue

The IP.com Prior Art Database

Abstract

In many plants producing mononitrobenzene methods like thermolysis are used to decompose by-products like nitrophenolates in the waste water. A method to measure the content of organic compounds in the waste water continuously was developed to increase the safety of these units.

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MONITORING ORGANIC COMPOUNDS IN THE WASTE WATER OF MONONITROBENZENE PRODUCTION

In many plants producing mononitrobenzene methods like thermolysis are used to decompose by-products like nitrophenolates in the waste water. To increase the safety of these units it is useful to measure the content of organic compounds in the waste water continuously especially the amount of nitrobenzene.

Measurement of undissolved organic compounds

One method is the measurement of undissolved aromatics (if the solubility limit is exceeded) by turbidity measurement. If a biphasic mixture occurs the content of nitroaromatics can be determined by measurement of the transmission or the backscattering in the NIR or UV spectral range in concentrations of 0-3 weight-% nitrobenzene in water. One disadvantage is the risk of depositions on the measurement device. To minimise that risk the maintenance intervals for the equipment should be quite short.

Measurement of dissolved/undissolved organic compounds

a) Stripping of waste water at temperatures where aromatics (0-1500 ppm) can be removed e.g. 90°C at ambient pressure for nitrobenzene) and analysis by a calibrated flame ionisation detector (FID). This method is fast and robust and shows no interference with phenolic by-products but is not selective to single components or isomers.

Example: The waste water is filtered continuously and the pressure is reduced close to ambient pressure. The water is heated to 90°C and all volatile components are stripped out with nitrogen at 90°C. Solid components that are present in the gas phase are removed by a heated filter at 180°C to...