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Thermal removal of COD and NH 3 N from Lurgi coal‐gasification wastewater
Author(s) -
Zhang Wei,
Wang Chang'an,
Li Guangyu,
Liu Yinhe,
Che Defu
Publication year - 2017
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.12600
Subject(s) - chemistry , wastewater , chemical oxygen demand , wood gas generator , thermal decomposition , residence time (fluid dynamics) , inert gas , decomposition , coal gasification , pulp and paper industry , coal , environmental chemistry , environmental engineering , environmental science , organic chemistry , engineering , geotechnical engineering
In this article, an alternative approach of wastewater utilization in coal‐gasification process was proposed and evaluated. With wastewater being heated and sprayed into the gasifier, water vapor is treated as gasification agent and contaminants are thermally decomposed under specific conditions. The lab‐scale experiments were performed using entrained‐flow reactor system to investigate thermal removal of COD and NH 3 N contained in wastewater by changing temperature, reaction atmosphere, oxygen proportion, and residence time. The experimental results show that reaction temperature has a significant effect on COD and NH 3 N removal, and removal efficiency is obviously increased with temperature increased from 400 to 1000°C. The removal efficiency of COD and NH 3 N in different atmospheres ranks in the order: oxidative > inert > reductive. The thermal decomposition of organic constituents is enhanced by increasing oxygen proportion and residence time. Furthermore, a simplified kinetic study of COD and NH 3 N removal efficiency was carried out on the hypothesis of pseudo‐first order reaction model. The pre‐exponential factor and apparent activation energy for COD and NH 3 N removal were obtained in the range of 3.63 × 10 3 −1.62 × 10 6 , 34.39–58.16 kJ mol −1 and 1.58 × 10 4 −8.71 × 10 5 s −1 , 41.25–61.75 kJ mol −1 , respectively. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1333–1341, 2017