Generally, rivers, lakes or groundwater are used as cooling water for air separation units. This kind of water usually contains suspended solids (sediment and other pollutants) and bicarbonates such as calcium and magnesium [- Ca (HCO3) 2 and Mg (HCO3) 2], which is called hard water. When there are many suspended solids, it is easy to block the channels, filters and valves of the cooler. Calcium, magnesium and other bicarbonates are easy to form calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) precipitates when the water temperature rises, that is to say scale. Generally, water temperature above 45 ℃ will start to form scale, and the higher the water temperature is, the easier it is to scale. After grouting for 7 days, tighten the screws and recheck the verticality of the tower again. Then, the pad iron and the base plate are spot welded firmly, and the slurry is sealed around; Install the connecting pipe, and check the air tightness of the flange and welded joint of the connecting pipe. Generally, it is qualified if there is no bubble in soapy water;
If the air separation plant manufacturer reduces the pressure, the corresponding saturation temperature will also decrease. Some saturated liquid will gasify and absorb heat, becoming a mixture of saturated liquid and saturated steam under low pressure, and the temperature is equal to the saturation temperature under the pressure. The throttling of liquid air and liquid nitrogen is in this case. The sieve plate column of air separation plant manufacturer is similar to the sieve plate column of distillation tower, but the number of plates is small (generally about 5), and the diameter and spacing of sieve holes are large (about 5mm in diameter and 9mm in spacing). The cooling water is ejected from the top through the spray device and flows down the tray through the sieve hole layer by layer. The air flows counter current through the sieve hole from the bottom of the tower and bubbles up. The air separation plant manufacturer should increase the circulating current first to keep the temperature in front of the unit at a high level (e.g. - 120 ℃), so that the carbon dioxide content in front of the unit is in an unsaturated state, and it is not easy for carbon dioxide to precipitate in the unit after expansion. When the temperature of the cold end reaches - 150 ℃, the amount of carbon dioxide brought into the expander is very small, so the bypass and circulation can be cut off temporarily, so that the temperature in front of the expander can be reduced rapidly, and the expander will not be blocked if it is forced to cross the carbon dioxide freezing zone in about 10 minutes.
Shorten the switching time and reduce the cold end temperature as soon as possible; When the cold end temperature meets the process requirements and the air separation unit enters the fourth stage, the expansion heat exchanger will not be started to prevent carbon dioxide from blocking the expansion heat exchanger. The boiling point of air separation plant manufacturer is the saturation temperature under the same pressure. They have the same meaning, but different views. The coexistence of gas and liquid is called saturation state. If the saturated steam is heated continuously, the temperature of the steam will rise. If the saturated temperature is exceeded, it is called superheated steam. In order to make the liquefier produce as much liquid as possible, i.e. to strengthen the heat exchange between the expansion gas and the low-temperature positive flow gas, the following measures can be taken by the air separation plant manufacturer under the condition of a certain liquefier size: increasing the pressure of the positive flow air. The higher the positive air pressure is, the higher the liquefaction temperature is and the lower the latent heat of condensation is. That is, the cooling capacity required for liquefaction is reduced, and the same cooling capacity can make more air liquefied.
