Failure mode 1:
Organic matter infiltration. Generally speaking, this form of failure is disastrous. All the membranes in the system were completely infiltrated in a short time (several hours), and the system was paralyzed, which would be disastrous for large-scale industrial production. This failure form must consider preventive measures in the design stage, and can't appear in practical application, which is the housekeeping skill of the professional engineers of DTEC.
Failure mode 2: High temperature damage. This damage mode only occurs in the first level and affects the second level at most. High temperature damage cannot be recovered, so effective measures must be taken to avoid it in the design stage. The professional engineers of DTEC are experienced in this field. Failure mode 3: Freezing damage. When the cold wave comes, if anti-freezing measures are not taken in time, once the film freezes, it will cause damage to the film, and this damage is irreversible. The professional engineers of DTEC considered this problem in the design stage, so customers don't have to worry. Failure mode 4: The degassing rate decreases. This is a common, slight and easily recoverable failure. According to the different reasons for the decline of degassing rate, it can be avoided and recovered by taking corresponding measures. For example, in the application of membrane deamination, there are many solutions to the problem of the decrease of degassing rate caused by the decrease of acid flux. For details, we can consult the professional engineers of DTEC to provide technical support. Failure mode 5: The degassing rate fluctuates greatly. A deamination case was observed, and the degassing rate fluctuated sharply from -4% to 66%, which was due to the influence of some substances in raw water on the membrane. These substances are not valued by system design engineers, and the causes of the problems are hard to find. The analysis and evaluation of these substances in raw water are know-hows designed by DTEC system. It is recommended that customers adopt the system design of DTEC to avoid unexpected failure problems of other engineering companies. Failure mode 6: Low ammonium salt concentration. There are many reasons why the concentration of discharged ammonium salt can't meet the design requirements. First of all, membrane contactors with good hydrophobicity should be used, for example, the penetration pressure should be higher than 0.6MPa, which is the landmark index of DTEC membrane; Secondly, the number of films used should be less. The amount of ammonia to be removed is certain, and more membrane amount means more water permeating, which will reduce the concentration of ammonium salt; Third, the system design must consider the complex water balance problem caused by many factors. These possible factors are: imported ammonia nitrogen concentration, added acid concentration, temperature, raw water salt concentration, membrane quantity, etc. We can't simply think of membrane contactor as "degassing membrane". For the complex mass transfer process in membrane contactor, the influence on water balance in some cases can't be ignored. In the research of mass transfer in membrane contactors, DTEC has taken the lead in the world. Based on the test results and engineering experience, DTEC can predict the concentration range of discharged ammonium salt for customers and effectively control it. Failure mode 7: Short membrane life. There are many factors affecting the membrane life, and the most important one is to choose the membrane with high penetration pressure (hydrophobicity). The penetration pressure (hydrophobicity) of DTEC membrane is greater than 0.6MPa, while the use pressure is less than 0.2MPa, and the pressure is 0.4MPa. Of course, it takes a long time for water to penetrate. In addition, deamination load, PH of acid-base side, temperature, pressure balance, cleaning process, etc. will also significantly affect the membrane life. The design of membrane life extension must have rich engineering experience and pay attention to the detailed parameters that affect membrane life for a long time. We have observed that the membrane life of 3M company in the United States, which is the best in the world, is only one year in a project. Obviously, there is a big problem in the design of the system. In terms of prolonging the membrane life, the professional engineers of DTEC have great advantages.
