连续闭式循环氨脱除工艺响应面法优化

Optimization of Continuous Air-recirculation Process for Ammonia Removal by Response Surface Methodology

摘要:

针对两阶段闭式循环氨脱除工艺处理猪粪厌氧消化液耗时、耗碱、难以达到工业化大量污水处理的需求问题，进行了连续闭式循环氨脱除工艺的试验研究。试验结果表明，对于起始氨氮质量浓度为(1444±37)mg/L的猪粪厌氧消化液，在气流量为530L/h、液流量为445mL/h、气液比为2036条件下，氨氮脱除率可达(66.81±0.24)%。经RSM优化的模型能够很好地分析和预测该工艺及系统条件下猪粪厌氧消化液的氨氮去除结果。所选自变量对于氨氮脱除的影响力从大到小依次为：气液比、液流量、气流量。研究结果可为猪粪厌氧消化液的连续处理提供依据。

Abstract:

Anaerobic digestate of pig manure has the characteristics of continuous and quantitative poly. The effluent of anaerobic digestate contains a large amount of ammonia nitrogen. The processing capacity of the two stage air-recirculation stripping process is difficult to meet industrial requirements for treatment of anaerobic digestate of pig manure. Gas flow rate, liquid flow rate and gas-liquid ratio were chosen as running parameters of continuous air-recirculation process. The running parameters were studied and the process was optimized by response surface methodology. The initial ammonia nitrogen concentration of anaerobic digestate was (1444±37)mg/L. Ammonia nitrogen removal rate could reach (66.81±0.24)% when the gas flow rate, liquid flow rate and gas-liquid ratio were 530L/h, 445 mL/h and 2036, respectively, which was the best optimal parameters combination. The model optimized by response surface methodology could well analyze and predict ammonia nitrogen removal efficiency of continuous air-recirculation process for treating anaerobic digestate of pig manure. Gas-liquid ratio was the limiting factor for the process of continuous air-recirculation stripping process. According to perturbation plots of ammonia removal efficiency, the influence order from large to small of the three selected parameters for removal ability of ammonia nitrogen was gas-liquid ratio, liquid flow rate and gas flow rate. The process could be used to strip and recover ammonia nitrogen from anaerobic digestate of pig manure. It could reduce foaming tendency of treated fluid and the foams could be broken more quickly than the two stage air-recirculation stripping process. The process could reduce the height of stripping tower and investment of engineering. The result can provide some references for the continuous processing for anaerobic digestate of pig manure.