First, the bottom of the air cooling tower liquid level interlock failure, the operator failed to find in time, resulting in the air cooling tower liquid level is too high, a large amount of water by air entrained into the molecular sieve purification system, activated alumina adsorption susaturated, molecular sieve water. The second is that the circulating water fungicide is non-bubble-free, the fungicide hydrolyzes with the circulating water, resulting in a large amount of foam, and enters the air cooling tower through the circulating water system, a large amount of foam accumulates between the air cooling tower distributor and the packing, and the air drives this part of the water-containing foam into the purification system, resulting in the inactivation of molecular sieve. Third, improper operation or compressed air pressure reduction, resulting in air cooling tower pressure reduction, too fast flow rate, short gas-liquid residence time resulting in gas-liquid entraining, a large number of cooling water out of the air cooling tower into the purification system, resulting in the adsorption of water, affecting the safe operation of molecular sieve. The fourth is the internal leakage of methanol-circulating water heat exchanger, and methanol leaks into the circulating water system. Under the biological action of nitrifying bacteria, a large amount of floating foam is generated, which enters the air cooling tower with the circulating water system, causing the distribution of the air cooling tower to be blocked, and a large amount of water-containing floating foam is brought into the purification system by air, resulting in the inactivation of the molecular sieve with water.
Based on the above reasons, in the actual process of production, the following measures can be taken.
First, Install a moisture analysis table in the outlet main pipe of the purifier. The moisture in the outlet of the molecular sieve can directly reflect the adsorption capacity and adsorption effect of the molecular sieve, so as to monitor the normal operation of the adsorber, and find out the first time when the water accident of the molecular sieve occurs, so as to ensure the safe and stable operation of the distillation plate heat exchanger and the air compressor unit, and prevent the occurrence of ice blocking accidents on the plate.
Second, in the pre-cooling system driving process, the water intake of the air cooling tower should be strictly controlled within the range of design indicators, and the water intake can not be increased at will; Secondly, it is to adhere to the principle of “advanced gas after water” to air cooling tower, strictly control the amount of air into the tower and the pressure increase rate, when the air cooling tower outlet pressure rises to normal, then start the cooling pump, establish cooling water circulation, to prevent pressure fluctuations or adjust the cooling water volume is too large to cause gas and liquid entrain phenomenon.
Third, regularly check the operating status of the molecular sieve, found that the white failure particles are too much, the crushing rate is too large, then replace the molecular sieve in time.
Fourth, the selection of micro-bubble type or non-bubble type circulating water fungicide, according to the circulating water operating parameters, timely add fungicide, to avoid a large number of one-time adding circulating water fungicide, resulting in excessive hydrolytic foam phenomenon.
Fifth, in the process of adding fungicide to the circulating water, part of the raw water is added to the water cooling tower of the air separation precooling system to reduce the surface tension of the circulating water and achieve the purpose of reducing the amount of circulating water foam entering the air cooling tower. Sixth, regularly open the additional discharge valve at the lowest point of the molecular sieve inlet pipe, and timely discharge the water brought out by the air cooling tower.
Post time: Aug-24-2023
