Kinetics of Ammonium Thiosulfate Wet Air Oxidation under High‐Temperature Conditions

Abstract

To remove H2S and HCN from acid gases, wet‐oxidative desulfurization such as the Takahax process can be applied. There, a continuous wastewater stream with high concentrations of ammonium thiosulfate and thiocyanate is discharged. By wet air oxidation of these salts at 473–573 K, fertilizer‐grade ammonium sulfate can be obtained. Thiosulfate wet air oxidation kinetics was investigated under industrially relevant conditions via the oxygen consumption rate in a high‐pressure reactor. Kinetic parameters were estimated with a dynamic reactor model. The experimental data was reproduced with a good average deviation of 2.17 %, and the applied reaction pathway is simple due to the high temperatures. This is an important step towards taylor‐made reactors for wet air oxidation of Takahax wastewater.

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“…Wet oxidation (WO) is a well-known process for treating liquid wastes with high organic matter contents. This process has shown high efficiency and cost-effective behavior compared to those technologies applied to wastes too diluted to be incinerated but too concentrated or poorly biodegradable to be treated by the usual biological or chemical treatments [1][2][3]. These wastes include mainly organic sewage sludge from municipal or industrial wastewater treatment plants (WWTPs) with a solids content of up to 5%, without dewatering and/or drying the sludge.…”

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“…Wet oxidation (WO) is a well-known process for treating liquid wastes with a high organic matter content. This process has shown high efficiency and cost-effective behavior compared to those technologies applied to wastes too diluted to be incinerated but too concentrated or poorly biodegradable to be treated by the usual biological or chemical treatments [1][2][3]. These wastes include sewage sludge from municipal or industrial wastewater treatment plants (WWTPs), without dewatering and/or drying the sludge, with a solids content up to 5% and mainly organic.…”