面向池塘圈养模式的气液混合泵的参数优化及增氧试验

Parameter optimization and oxygen aeration test by gas-liquid pump for pond aquaculture of captive-pond mode

为探究气液混合泵能否满足在高密度养殖条件下养殖对象对水体溶氧的需求,基于气液(氧气-水)混合泵搭建溶氧试验平台,在不同水温、不同出水压力和不同气水体积比的条件下,测试气液混合泵溶氧性能,并在池塘圈养桶(直径4 m,高2 m,养殖水体体积20 m^(3))内进行增氧试验。溶氧性能测试结果显示:当出水压力为0.25 MPa、气水体积比为0.01~0.05时,在不同水温(5.6、13.5、30.3)条件下出水溶解氧与水温成反比,溶解氧在47.93~20.60 mg/L变化;氧气吸收效率与气水体积比呈反比,氧气吸收效率在91%~33.7%变化;动力效率与气水体积比成正比,动力效率在22.32~55.12 kg/(kW·h)变化。基于圈养桶的增氧试验结果显示,在有鱼耗氧的条件下(黄颡鱼,单个桶内养殖密度为13.19~16.49 kg/m^(3)),使用功率3 kW的气液混合泵为4个圈养桶增氧时,每个桶内水体溶解氧在光照时间内可达11 mg/L,夜间稳定保持在8 mg/L以上。试验结果表明气液混合泵可应用于高密度的水产养殖,并能有效应对夏季高温供氧难题。

Aquaculture of captive-pond mode has higher sewage treatment efficiency and breeding density,which is due to the benefit of frequent removals of aquaculture waste in the captive tank.However,dissolved oxygen in high density aquaculture water is a concern for farmers.When the water temperature is high in summer,air aeration is inefficient,and the bubble-based aeration method cannot meet the requirements of oxygen supply.Gas-liquid mixed pump has a great performance on increasing dissolved oxygen in sewage aeration treatment.To explore whether gas-liquid mixed pump is suitable for the oxygen enhancement in the captive-pond mode,it is necessary to explore the optimal process parameters through experiments.In this study,the performances of the pump were tested under different water temperatures,outlet pressures and gas-water volume ratios,and the field tests were carried out in the pond captive tank(diameter 4 m,height 2 m,aquaculture water volume 20 m^(3)).The results showed that,under the conditions of outlet pressure of 0.25 MPa and gas-water volume ratio of 0.01 to 0.05,the dissolved oxygen in outlet water was inversely proportional to the water temperature(5.6℃,13.5℃and 30.3℃),and the dissolved oxygen varied from 47.93 mg/L to 20.60 mg/L.The oxygen absorption efficiency was inversely proportional to the gas-liquid volume ratio,and the oxygen absorption efficiency varied from 91%to 33.7%.The dynamic efficiency was proportional to volumetric gas-liquid ratio and varied from 22.32 kg/(kW·h)to 55.12 kg/(kW·h).Field test showed that,under the condition of fish oxygen consumption density of about 13.19 to16.49 kg/m^(3),when the pump’s working power was about 3 kW,the dissolved oxygen of each captive tank can reach 11 mg/L in the daytime and keep above 8 mg/L at night.The fluctuation of dissolved oxygen in the captive tank was within 0.2 mg/L,and the uniformity was good.The pump system is simple in structure and can work efficiently under high water temperature conditions.