高径比对猪场废水脱氮与沼气脱硫耦联反应器的影响

采用填料鼓泡塔反应器研究其高径比对猪场废水脱氮与沼气脱硫耦联过程的影响,比较了3种不同高径比(8∶1、3∶1、2∶1)反应器的废水脱氮与沼气脱硫效能.在温度30～32℃、空塔停留时间6.70 min、水力停留时间3.35 d、沼气中H2 S浓度1 414～1 838 mg.m-3、进水NO x--N浓度114～243 mg.L-1的条件下,高径比2∶1反应器的运行较稳定,且处理效果较好,硫化氢去除率平均值为96.7%,NO x--N去除率平均值达到88.7%;而高径比8∶1和3∶1反应器的运行不太稳定,硫化氢去除率的平均值分别为68.0%、80.4%,NO x--N的去除率平均值分别为89.7%、90.2%.主要是因为高径比2∶1反应器的实际气速(3.12×10-2 m.s-1)比高径比3∶1、8∶1反应器的实际气速(分别为3.62×10-2 m.s-1和6.64×10-2 m.s-1)更慢,其气液传质系数(1.79×10-5 s-1)比高径比3∶1、8∶1反应器的气液传质系数(分别为1.64×10-5 s-1和1.55×10-5 s-1)更大,传质效果更好.处理效能试验结果以及反应器流体力学特征参数均表明,高径比2∶1反应器为最适合的反应器.

Effect of the Ratio of Height to Diameter on the Performance of the Simultaneous Reactor for Nitrogen Removal from Swine Wastewater and Sulfide Removal from Biogas

The effect of the ratio of height to diameter (H/D) on the process of simultaneous nitrogen removal from swine wastewater and hydrogen sulfide removal from biogas was investigated, using the bubble column reactors with packing material. The performance of the reactor with H/D of 8 : 1, 3 :1 and 2 : 1 was compared. Under temperature of 30-32 degrees C, gas retention time of 6.70 min, hydraulic retention time of 3.35 d, hydrogen sulfide concentration of 1 414-1 838 mg x m(-3) in biogas, and NO(x)(-) -N concentration of 114-243 mg x L(-1) in influent. The reactor with H/D of 2 : 1 achieved a stable and good treatment result, with the average removal rates of 96.7% for hydrogen sulfide, and 88.7% for N(x)(-) -N. While the reactors with H/D of 3 : 1 and 8 : 1 obtained unstable and inferior results, with the average removal rates of 68.0%, 80.4% for hydrogen sulfide respectively, and 89.7%, 90.2% for NO(x)(-) -N respectively. The reason could be attributed to the following facts. The reactor with H/D of 2:1 has a slower optimum gas velocity (3.12 x 10(-2) m x s(-1))- than the reactor with H/D of 3 : 1 and 8 : 1 (3.62 x 10(-2) m x s(-1) and 6.64 x 10(-2) m x s(-1) respectively), and has a higher gas-liquid mass transfer coefficient (1.79 x 10(-5) s(-1)) than the other two reactors (1.64 x 10(-5) s(-1) and 1.55 x 10(-5) s(-1) respectively). Results of the performance and the hydrodynamics parameters of the reactors all indicated that the reactor with H/D of 2 : 1 was more suitable for the process of simultaneous nitrogen and hydrogen sulfide removal.