Catalytic hydrothermal gasification of the organic compounds dissolved in waste water from coal dewatering and industrial processes

摘要

A novel Ni/carbon catalyst recently developed by the authors was used to gasify organic compounds dissolved in the wastewater with TOC concentration from 0.2 percent to 2 percent. The process removes the organic compounds by gasifying them into high calorific gases like methane and hydrogen. The investigations were focused on the efficiency of the Ni/carbon catalyst in terms of carbon conversion, conversion of big organic molecules, and catalyst deactivation due to sintering. The preliminary results showed that up to 99 percent carbon conversion can be achieved at 350 deg C, and 20 MPa. The conversion mechanism was believed to consist of two steps: first, degradation of big molecules to small molecules followed by gasification of small molecules by H_2O to produce CH_4 and CO_2. The catalyst was highly active and stable and no sintering was observed even after 50 h of reaction time.