1.What is reflux ratio?What effect does it have on rectification？
Reflux ratio refers to the ratio of the amount of liquid flowing down the rectification column to the amount of steam rising in the rectification column.
When reflux ratio is large, nitrogen purity in gas phase is high and oxygen purity in liquid phase is low. When reflux ratio is small, nitrogen purity in gas phase is low and oxygen purity in liquid phase is high.
2.What are the causes of molecular sieve water inlet accidents?
a.When the liquid level of the air cooling tower is higher than 3500mm, the water exceeds the height of the air inlet pipe, and a large amount of water enters the molecular sieve adsorber with the air.
b.When the resistance of the air cooling tower rises above 7kPa, liquid suspension will be formed in the air cooling tower, resulting in fluctuation of water level at the bottom. fluctuation of resistance of the air cooling tower, and water entering the molecular sieve adsorber with air.
c.Due to the disorder of molecular sieve switching process, air suddenly passes through the air defense of molecular sieve adsorber, and the airflow speed in the air cooling tower accelerates sharply, and water enters the molecular sieve adsorber with air.
d.The air pressure of the instrument decreases, and the pneumatic valve is out of control, causing the water level to rise.
e.Cooling water, frozen water flow is too large, so that the air cooling tower liquid suspension.
3.What are the preventive measures against accidents of expander.
a.Expander front bearing temperature alarm value is 70 deg C, interlock value is 75 deg C.
b.The reflux valve gradually opens when the speed of the expander exceeds the alarm value, and the expander stops when the speed exceeds the interlock value.
c.The flow rate of the booster is lower than the minimum alarm value, and the reflux valve of the expander is fully open.
d.When expander inlet temperature is less than 180deg C, the inlet valve is closed.
4.What should be noted in the operation of the booster expander.
a.Under no circumstances is it allowed to remove the interlock to start the expander;
b.Control the expander inlet temperature not lower than 118 deg C.
c.It is not allowed to start the expander when the bypass valve FCV401 of the booster is closed. The first use of the expander or the use of the expander in the hot state shall be pre-cooled.
