厌氧消化液氨氮吹脱回收整体处理装置设计与中试试验

Design and Test of Integrated Device for Ammonia Nitrogen Stripping and Recovery of Anaerobic-digested Effluent

为了促进氨氮吹脱回收工艺处理厌氧消化液的工程化应用,针对投碱量较大、吹脱时易产生泡沫和能耗较高等问题,设计了一套厌氧消化液氨氮吹脱回收整体处理工艺装置。该整体处理装置由高效预处理单元、p H值调节单元及氨氮吹脱与回收单元3个功能单元组成,采用了低耗逆流循环吹脱方法。完成设计后在京郊沼气站进行了中试装置示范搭建,并于2015年8月—11月中旬进行了现场中试试验和工艺优化。结果表明,投加22 g/L生石灰时厌氧消化液pH值可达到运行要求值（10.5以上）,并且在水温和气液比分别为（30.7±2.5）℃和960时,氨氮去除率可达（55.8±2.2）%。研究发现虽然投加石灰干粉具有简便性,但是利用率较低,采用投加石灰浆的方法可以有效避免投加干粉的缺陷,可减少7.5 g/L的投加量。同时研究发现不同厂商生石灰中有效氧化钙的含量差别较大,提升厌氧消化液pH值的性能存在较大差异,并分析得出了不同温度下的建议投碱量。该整体处理装置在常温和低气液比（0~1 000）条件下达到了相对稳定的氨氮脱除效率,具有较好的应用推广前景。

The treatment of anaerobic digestion effluent has become the bottleneck of large-scale biogas station application in China. In order to promote the engineering application of ammonia nitrogen stripping and recovery of anaerobic digestion,an integrated equipment for ammonia stripping and recovery with relative low cost was designed and constructed on-site to demonstrate its efficiency in real biogas plants,decrease lime dosage and control foam. This device mainly consisted of three functional units：pretreatment unit,p H value adjustment unit and ammonia stripping and recovery unit. To reduce the energy consumption,economical reflux circulated stripping method was adopted. A pilot test was carried out by using swine manure anaerobic-digested effluent at a biogas station of Beijing suburbs,the results showed that p H value of anaerobic digestion can be reached 10. 5 by adding 22 g lime per liter after four months experiment and optimization,and ammonia removal rate reached 55. 8% when the temperature and gas-liquid ratio were 30. 7℃ and 960,respectively. Although adding dry lime powder was easily operated,the dissolved efficiency was relatively low. Pre-dissolved lime slurry can effectively avoid the defects and reduce the dosage by 7. 5 g / L. Moreover,the effective calcium oxide content of lime fromdifferent producers had significant differences. And the performance of lime from different producers in increasing anaerobic digestion effluent p H value was compared and the lime dosage was also analyzed at different temperatures. Finally,higher ammonia removal rate could be attained by using this integrated device under ambient temperature and low air-liquid ratio（ 0 ~ 1 000）.