Air separation precooling system

When the air is out of the air compressor, due to the compression, the moisture in the air is in the saturated state. After the water cooling column decreasing the temperature, the water content in the saturated state decreases, and the excess water condenses into the water. The water volume in the air cooling column increases and the water temperature rises. But not only is the temperature of the air reduced, but also the moisture content of the air. In the water cooling column, the crude nitrogen is used to cool the water. After passing through the main heat exchanger from the fractionator, the temperature of the crude nitrogen is close to the normal temperature, but it is very dry. The dry crude nitrogen contacts with the water, and a large amount of water is evaporated into the crude nitrogen by using the unsaturation of the crude nitrogen, which absorbs the heat of the water and reduces the water temperature.

For the maintenance of nitrogen-water precooling system, the most important thing to pay attention to is to prevent the occurrence of nitrogen suffocating accident. There have been several lessons that maintenance workers died of nitrogen suffocating in China. During the overhaul, nitrogen is often used to warm the unit at the same time, and the heated nitrogen often flows into the cooling tower through the three-way valve of dirt and nitrogen, causing the nitrogen concentration in the tower to be too high. Therefore, before heating the device, the air cooling tower and water cooling tower should be separated from the device by blind plate; the oxygen content in the air cooling tower and water cooling tower should be analyzed. When the oxygen content is 19% ~ Only between 21% can the maintenance personnel be allowed to enter; if they work in the area where the oxygen content is less than 19%, there must be someone to supervise and wear isolation masks (oxygen respirator, long tube m...