SONGXiao-ya.Abnormal Methane Content in a Thermal Hydrolysis Anaerobic Digestion Tank and Countermeasures[J].China Water & Wastewater,2024,40(24):59-63.
热水解厌氧消化池甲烷含量异常及应对措施
- Title:
- Abnormal Methane Content in a Thermal Hydrolysis Anaerobic Digestion Tank and Countermeasures
- Keywords:
- thermal hydrolysis; anaerobic digestion tank; volatile fatty acid; acidification; temperature control; methane
- 摘要:
- 针对某热水解厌氧消化池甲烷含量明显降低的情况，分析了挥发性脂肪酸、碱度和沼气产率等指标变化，并与正常消化池进行对比。异常消化池内挥发性脂肪酸>5 000 mg/L，表明出现挥发性脂肪酸积累（酸化）。进一步分析有机负荷、停留时间和温度对酸化的影响，发现温度过高是导致酸化的主要因素，而51 ℃是重要分界点。针对异常情况采取的应急措施是通过减少进泥量和清洗换热器的方式降低消化池温度。消化池恢复过程中甲烷含量指示作用最灵敏，其次是挥发性脂肪酸，碱度最不敏感。对热水解厌氧消化池的优化建议是进行温度控制和建立监控体系。近期温度控制以50 ℃为警示值，远期考虑进行设施和自控改造。监控体系以甲烷含量为首选监测指标，可采用便携式分析仪检测，频次以周为单位。
- Abstract:
- In view of the obvious decrease of methane content in a thermal hydrolysis anaerobic digestion tank, the changes of volatile fatty acids, alkalinity and biogas yield were analyzed and compared with those in a normal digestion tank. The content of volatile fatty acids in the abnormal digestion tank exceeded 5 000 mg/L, indicating the accumulation of volatile fatty acids, i.e., acidification. The effects of organic load, residence time and temperature on acidification were further analyzed. Excessive temperature was the main factor leading to acidification, and 51 ℃ was an important critical point. The emergency measures taken for abnormal conditions were to reduce the temperature of the digestion tank by reducing the amount of inlet sludge and cleaning the heat exchanger. The methane content index was the most sensitive in the recovery process of digestion tank, followed by volatile fatty acids, and alkalinity was the least sensitive. The optimization suggestions of thermal hydrolysis anaerobic digestion tank are temperature control and establishment of monitoring system. Temperature control should take 50 ℃ as the warning value in the near future, and facilities and automatic control transformation should be considered in the long term. The methane content detection is recommended as the preferred monitoring index in monitoring system, using a portable detector with frequency of week.
相似文献/References:
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