| Hollow fiber membrane modules with its unique advantages were widely used in various fields,the integrity testing of membrane modules for the continued use of membrane water treatment technology was essential.Based on the analysis of relevant research at home and abroad,this paper put forward an on-line detection method and testing device of hollow fiber membrane module integrity based on the principle of light blockage method.Through the electrical signal changed caused by photoelectric resistance detector received the light intensity to determine the integrity of the membrane module.After optimizing the electric circuit and experimental device design,comparing the experimental conditions,a set of commercial membrane integrity testing device was researched and developed independently.Finally,the particle in water was researched by the detection.First of all,taking the lake as the separation fluid,the phenomenon of the change of the voltage signal before and after the damage of the membrane module and the precision of the detection device are studied.membrane integrity testing device using 650nm red laser as the light source,the III type photoresist detector as the optical receiver.The results showed that the optimized experimental circuit voltage reference constant at 2.3553 ± 0.0025V when the membrane module was complete;when the membrane module is damaged,the voltage pulse signal and the voltage pulse signal intensity are caused by the micro-bubbles of the detection device respectively corresponding to the size and the number of the bubbles passing through the detection device,and the minimum diameter size of the micro-bubbles detectable by the detection device is 220 ?m;In addition,the bubble size has a good linear relationship with the voltage pulse intensity,and the micro-bubble size detected by the detection device can be predicted by the voltage pulse intensity.Secondly,the sensitivity of the optimized detection device for different breakage rate of membrane modules was studied,and the influence of membrane flux and aeration intensity on the micro-bubbles of the detection device was analyzed.The results showed that the addition of two bubble fusion elbows in the outlet pipe can converge the micro-bubbles into large bubbles and greatly improve the sensitivity of the membrane integrity detection device.With the increase of the membrane module damage rate,the sensitivity of the detection device lower slightly,but the sensitivities were all more than 95%.The interaction between membrane flux and aeration intensity has a synergistic effect on the micro-bubbles passing through the detection device.The results showed that membrane flux and aeration intensity mainly affected the number and size of micro-bubbles.When the membrane flux and aeration intensity were 28L/(m2 · h)and 300L/(m2 · h)respectively,The membrane integrity can be distinguished by the pulse voltage caused by micro-bubbles in time.The detection device should adjust membrane flux and aeration ration according to the size of membrane module and the range of aeration pump in practical application.Thirdly,the experimental results of the detection device in this paper were compared with the commercial particle counter,and the operation control and the cost were estimated.The results showed that the particle number detected by the particle counter and the change of the number of micro-bubbles detected by the detection device have the same trend,and all have a linear correlation,which proves the feasibility of the detection device in the method and the practical application;the detection device Finished product after a long run,the performance was stable,in addition,it was low cost and has a certain practical value.Finally,the hollow fiber membrane module integrity monitoring device was used to investigate the particle.The results showed that the integrity detection device has a linear relationship between the detection voltage and the particle counter.The correlation coefficient R2 was 0.9994,indicating that the membrane integrity testing device can characterize the amount of particle by detecting the voltage value. |
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