Autothermal reforming of distillery wastewater: Thermodynamic modelling and experimental results

Distillery wastewater (DW) is a byproduct of the wine distillery industry, posing environmental challenges due to its pollutant nature and costly disposal. This study investigates steam reforming as a method for treating and valorizing DW by removing pollutants while generating renewable hydrogen. Traditional reforming (TR) and autothermal reforming (ATR − combining steam reforming and partial oxidation) processes are explored across varying DW compositions (mix 1–5) derived from lees, pomace, and wine. Simulations are performed under different conditions (temperature: 300–1000 °C, pressure: 1–20 bar, and oxygen-to-carbon ratio: 0–0.5 mol O2·mol C−1). Results show mix 2 (from lees) yields 9.06 mol H2·mol DW−1 at 500 °C and 1 bar. For mix 2, the TR achieves a relative H2 yield of 99.78 %, and the ATR 88.16 %. Despite producing less hydrogen, ATR reaches thermally neutral operation, since the oxidation reactions are exothermic. Experimental validation utilizing a fixed-bed reactor with a Ru-Ni catalyst supported on SiO2 and doped with La2O3 is performed for temperatures of 300–700 °C, 1 bar pressure, weight-hour space velocity (WHSV) of 12.1 h−1 and oxygen-to-carbon molar ratio of 0.22 mol O2·mol C−1. Thermodynamic equilibrium is reached experimentally at temperatures exceeding 500 °C for TR and 600 °C for ATR, matching simulation results.