Proof of concept of hydrothermal oxidation for treatment of triazine-based spent and unspent H2S scavengers from offshore oil and gas production

• The COD of spent H 2 S scavengers was reduced up to 98% by hydrothermal oxidation. Increase temperature from 200 350 °C enhances the reaction rate seventyfold. Triazine, monoethanolamine and dithiazine were converted in less than 1–3 min. Organic nitrogen sulfur are mainly into ammonium sulfate. Short chain carboxylic acids, pyrazines pyridines intermediate products. feasibility oxidation a wastewater derived scavenging operations, carried out topside offshore oil gas installation, demonstrated. feed characterization showed presence unreacted triazine (unspent scavenger), (spent scavengers). unspent (SUS) subjected batch reactor at approximately (low temperature, LT) (high HT), using oxygen excess. experiments performed for six times each range 3 360 min LT 1 120 HT. Diluted SUS (COD around 30 g/kg) used as feed. three main compounds not found any products, which means they fast converted. reductions 84% obtained HT, respectively. A equation second order with respect suitable represent disappearance COD, constant HT 70 higher LT. extensive analysis on products C1-C4 clear trend towards complete mineralization organic ammonium, except small amounts nitrate LT, sulfate, observed.