Carbon consumption mechanism of activated coke in the presence of water vapor

• Published in: Environmental science and pollution research international 2020, Vol.27 (2), p.1558-1568
• Main Authors: Guo, Junxiang, Li, Yuran, Wang, Bin, Zhu, Tingyu
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorption; Ammonia; Aquatic Pollution; Atmosphere; Atmospheres; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Carbon - chemistry; Carbon dioxide; Carbon sources; Carbonates; Carboxylic Acids; Coke; Consumption; Decomposition; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Flue gas; Fourier transforms; Functional groups; Infrared spectrometers; Operating costs; Organic chemistry; Purification; Regeneration; Research Article; Steam; Sulfur dioxide; Waste Water Technology; Water Management; Water Pollution Control; Water vapor
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-019-06747-x

To reduce chemical carbon consumption in activated coke technology used for flue gas purification, the carbon consumption mechanism of commercial activated coke in the presence of water vapor was studied. A fixed-bed reactor and a Fourier transform infrared (FTIR) spectrometer were combined to study the amount of carbon consumption. Temperature-programmed desorption (TPD) coupled with in situ diffuse reflectance infrared Fourier transform (in situ DRIFT) spectra were used to investigate functional group changes of activated coke. The sources and factors influencing carbon consumption in various adsorption atmospheres and in the N 2 regeneration atmosphere were compared. Carbon consumption during the adsorption and regeneration process was mainly due to the release of C–O and C=C groups. The addition of H 2 O increased the formation of carbonates and carboxylic acids during the adsorption process, which decomposed during the regeneration process, thereby increasing carbon consumption. Carbon consumption was reduced during regeneration in an H 2 O-SO 2 adsorption atmosphere, mainly because of the formation of C–S bonds, which reduced the formation of CO 2 . The C–N bonds generated in an H 2 O-NO adsorption atmosphere were decomposed during the regeneration process, thereby increasing carbon consumption. In a complex atmosphere of SO 2 , NO, NH 3 , and H 2 O, SO 2 was absorbed by NH 3 , and the amount of carbon consumption was consistent with that in the NO atmosphere during the regeneration process. The total carbon consumption in various adsorption atmospheres ranged from 85.4 to 125.2 μmol/g. Compared with an anhydrous atmosphere, chemical carbon consumption increased by 6.5–14.3% in the presence of H 2 O. Chemical carbon consumption was reduced by decreasing the H 2 O concentrations, which provides a reference concept for reducing the operating cost of the activated coke process in industry.