After adopting the supercharged turbine process, the expander is used to drive the supercharger to compress the expansion air from the air compressor, which can increase the inlet pressure of the expander to about 1.0MPa and increase the unit cooling capacity. Under the condition of a certain total cooling capacity, the amount of expansion air can be reduced, which is conducive to the distillation of upper tower.Our common refrigerators and air conditioners obtain low temperature by refrigeration process. It must consume electricity to drive the compressor. The material circulating in the refrigerator is called "refrigerant". It is a low boiling point substance, commonly used are ammonia, freon, etc.After the take-off pressure is adjusted, the lock nut should be tightened to prevent the adjusting screw from loosening, so that the take-off pressure can change automatically. At the same time, the cover shall be covered and lead sealed, and no arbitrary change is allowed. Lever rod type safety valve adjusts the take-off pressure by changing the position of the heavy hammer on the lever or the weight of the heavy hammer. After adjustment, it should be fixed and put in the iron box for protection to prevent unauthorized movement.
DEAR Air separation unit.In the air separation plant, the refrigeration capacity includes expander refrigeration capacity and throttling effect refrigeration capacity. After the expansion air of medium pressure air separation unit enters the lower tower for liquefaction, it also enters the upper tower through liquid throttling, while the expansion air of low pressure air separation unit no longer passes through throttle valve. So, is it true that only the part of gas (or liquid) passing through the throttle valve can produce throttling effect and refrigeration capacity? In fact, this is not the case.DEAR Air separation unit.The water supply and drainage of nitrogen water precooling system is an independent circulation system. Because of the large temperature rise of cooling water in the tower, high drainage temperature and serious scaling, it is required that the make-up water of the system should use low hardness water or soft water as far as possible, and its temporary hardness should not be greater than 8.5 ° DH generally. Other requirements are the same as that of compressor cooling water. Distilled water or soft water shall be used as lubricating water for cylinder of high pressure oxygen compressor for bottle filling.
In the actual expansion process, due to the loss of mechanical friction and eddy current, the external work is reduced. It also transfers the heat energy to the gas, so that the actual enthalpy drop is reduced, the unit cooling capacity is reduced, and the temperature drop is also reduced. The expander efficiency η P is the degree that the actual expansion process is close to the ideal expansion process, that is, the ratio of unit actual refrigerating capacity △ h and unit theoretical refrigerating capacity △ HT.In normal operation, the main operation of the condensing evaporator is to keep the oxygen level at the specified height. There are many reasons for the fluctuation of the main cooling liquid level, but in a word, it is caused by unbalanced cooling capacity or improper liquid distribution.The liquid level should be stable. The stability of liquid oxygen level indicates the balance of cooling capacity of the equipment. If the liquid oxygen level changes from high to low, it is very difficult to adjust the purity. The expansion volume and the opening of liquid air and liquid oxygen control valves should be adjusted reasonably to make the liquid oxygen surface stable.
In the actual operation, the situation is much more complicated than the design situation. The main factors affecting the operation cycle include the continuous working ability of the oxygen generator equipment and operating machinery, the quality of heating and blowing before starting, the level of operation in the starting stage and normal operation, the size of air load, etc.DEAR Air separation unit.When the working condition of the air separation unit is stable, the cold production and consumption of the unit keep balance, and the temperature, pressure, liquid level and other parameters of each part of the unit no longer change with time. The main cooling is the link between the upper and lower towers. The rising nitrogen from the lower tower is exothermic condensed in the main cooling, and the return liquid oxygen from the upper tower is endothermic evaporated in the main cooling. When the amount of reflux liquid is equal to the amount of evaporation, the liquid level remains unchanged.
