For pure matter, there is no essential difference between evaporation and boiling. Boiling point is also called "evaporation temperature". When the liquid sealed in the constant pressure container is heated, the temperature T of the liquid is lower than the boiling point ts, and it is all in the liquid state, which is called supercooled liquid;DEAR Air separation plant.Because desorption requires energy, it must absorb heat. This part of the heat comes from the molecular sieve bed itself, so the bed temperature decreases, and the gas outlet temperature decreases accordingly. In the heating stage, the heating gas is usually dirty nitrogen. The waste nitrogen passes through steam heater or electric heater.Damp insulation material will greatly reduce the thermal insulation performance and increase the loss of cooling. If the cold insulation box is not sealed tightly, after the internal temperature of the cold insulation box decreases, the external wet air will invade, and the internal condensation or even freezing may occur. Therefore, it is necessary to ensure the sealing of the cold box, and fill a small amount of dry gas to maintain micro positive pressure.
DEAR Air separation plant.The valve stem falls off. The reasons are: the fixed split pin is broken, the nut is loose, falls off, and the spring is broken. The fixing bolt falls off, causing the whole automatic valve to fall off. ）The valve stem is broken. The main reason is that the material of the valve stem is poor and the manufacturing is defective. Or the spring is too hard, the valve stem is under too much force in the process of opening and closing.DEAR Air separation plant.After switching, the working condition is normal. If the waste nitrogen automatic valve is damaged, the pressure of the upper tower will rise when the air is flowing, and the pressure will be normal when the waste nitrogen is flowing. When equalizing, the air leaks into the low-pressure system, resulting in the pressure reduction in the channel after equalizing, and the pressure of the low-pressure system increases.At the critical temperature and pressure, there is no obvious difference between the gas state and the liquid state; when the critical pressure is exceeded, when the temperature drops below the critical temperature, all of them become liquid, and there is no phase transition stage and latent heat of phase transition. On the contrary, the gasification process is the same.
DEAR Air separation plant.No matter in which part of the explosion, the reason is the existence of liquid oxygen (or oxygen rich liquid air), which causes the concentration, accumulation or precipitation of dangerous substances in the evaporation process, forming an explosive mixture, which promotes the explosion under certain conditions.DEAR Air separation plant.Pressure test of upper tower system. Close all valves of fractionator shell and connecting valves of argon tower. Then open the distillate extraction valve, install the upper tower pressure gauge and open the valve. Slowly open the liquid nitrogen throttle valve to make the upper tower pressure rise slowly. When the pressure reaches 0.03mpa, the pressure rise will be suspended.DEAR Air separation plant.The cold section of the reversible heat exchanger is generally the heat transfer between four cold fluids (oxygen, pure nitrogen, sewage nitrogen, circulating current) and one hot fluid (air). The flow rate and density of each fluid are different, and their channel number is also different. During the assembly of heat exchanger, the channels of cold and hot fluids are arranged alternately according to the number of channels of different fluids.
