XU Jin,FAN Zhun,L Qiu-ying,et al.Characteristics of Hydrothermal Carbonization Products of Municipal Sludge in Mountainous Cities[J].China Water & Wastewater,2020,36(21 21):21-27.
Characteristics of Hydrothermal Carbonization Products of Municipal Sludge in Mountainous Cities
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
21 21
Page:
21-27
Column:
Date of publication:
2020-11-01
- Keywords:
- mountainous city; sludge; sand content; hydrothermal carbonization; reaction time; reaction temperature
- Abstract:
- Effects of reaction temperature and time on solid and liquid hydrothermal carbonization products of the concentrated sludge without adding chemical conditioner in a wastewater treatment plant of a mountainous city were investigated.Twelve groups of experiments were set up by setting four reaction temperatures (200 ℃, 220 ℃, 240 ℃ and 260 ℃) and three reaction times (2 h, 4 h and 6 h). With the increase of reaction temperature and time, the yield of sludge-based hydrothermal charcoal decreased from 69.32% (200 ℃ and 2 h) to 59.49% (260 ℃ and 6 h), the functional groups of O—H, C—H and C=C were gradually degraded, H/C value and O/C value decreased, and the decarboxylation and aromatization reactions of hydrothermal charcoal were enhanced. Overall, increasing reaction temperature had a greater impact on hydrothermal carbonization of sludge than extending reaction time. Biochemical methane potential (BMP) experiments indicated that the content of refractory organics in liquid products increased with the increase of reaction temperature,complex organics such as phenol and furan derivatives inhibited the anaerobic reaction, and the cumulative methane production decreased accordingly.With the increase of reaction temperature and time, the carbon content showed an upward trend, while the contents of hydrogen, oxygen, and nitrogen decreased, and the high heat value (HHV), energy density, and energy yield of hydrothermal charcoal were all lower than those of the raw sludge. The high sand content of sludge had a significant influence on the element content and HHV of hydrothermal charcoal. It was suggested to control the sand content of sludge effectively.
Last Update:
2020-11-01