Batch methanogenic fermentation experiments of wastewater from a brown coal low-temperature coke plant

Coke plant effluents with high contents of organic compounds are mainly treated by biological aerobic fermentation after physical pre-treatment. In this study, a brown coal condensate wastewater from a low temperature coking process was fermented under methanogenic conditions in discontinuous experiments. By this fermentation, acetate, propionate, and the main polyphenolic compounds （catechol, resorcinol and hydroquinone） were degraded to a level below the detection limit. The COD was reduced by 72% with a residual concentration of 2.1 g/L. This anaerobic fermented wastewater had a residual BOD5 of 0.66 g/L and 2.2 L CH4 were formed per litre of wastewater. An abiotic pre-treatment for this wastewater with air had a negative effect on the COD reduction and decrease of colour on the methanogenic fermentation due to the autoxidation of polyphenolic compounds to humic-like compounds. This study showed that methanogenic fermentations in the treatment sequence of brown coal coking wastewaters could reduce energy consumption for aeration in further treatment processes and had the potential for a better effluent quality due to a less formation of recalcitrant humic-like compounds.

Waste to treasure:Reutilization of fluid catalytic cracking coke block as photothermal conversion material for water evaporation

This study aims to analyze the coking process and propose an effective method for the reutilization of fluid catalytic cracking(FCC)coke block.Herein,we analyzed the basic characteristics and chemical composition of FCC coke blocks.The results showed that the main components were carbon,oxygen,and aluminum,accounting for 60.8%,26.6%,and 11.5%,respectively.Under the conventional catalytic cracking reaction temperature from 500℃ to 600℃,the formation of the first aromatic hydrocarbon was particularly important for the formation of coke.The condensation of oil-gas-entrained catalyst particles and their heavy components was the physical cause of coking,while the dehydrogenation condensation reaction of oil-gas heavy components was the chemical factor.In addition,the membrane prepared by powdered coke had excellent photothermal conversion ability,which could be heated to more than 110℃ within 360 s under two fixed light intensities.The evaporation rate of photothermal water was 5.89 kg m^(2) h^(−1),which has great industrial application potential.These works provide a novel and effective method of separation membrane for the reutilization of FCC coke blocks.