In this case, the operation of the crude argon column should be stopped first, and the temperature of the crude argon condenser should be increased. After thawing, gradually put the crude argon column into operation again; pay attention to the nitrogen content in the fraction. When the nitrogen content exceeds 0.1%, it will not only make it difficult to condense the fraction, but also increase the nitrogen content of the crude argon, which will affect the operation of the refined argon tower.DEAR Air separation equipment.First of all, the steam pressure and flow rate required for the molecular sieve heating should meet the requirements of process design. Heating regeneration process can be judged by regeneration temperature curve. Pressure relief stage: due to the decrease of pressure, the adsorption capacity of molecular sieve decreases, and the water and carbon dioxide molecules that were originally adsorbed are partially desorbed, resulting in the decrease of temperature.In other words, because part of the liquid gasification needs heat absorption, the temperature after throttling will decrease. Generally, the gasification rate y of saturated liquid in air separation column can reach 17% ~ 18% after throttling. The subcooler uses the low temperature gas from the upper tower to cool the saturated liquid from the lower tower, so that the temperature is lower than the saturation temperature.
DEAR Air separation equipment.The temperature drop of air from 0.6MPa throttling to 0.1MPa is only about 1 ℃, while the temperature drop can reach 80 ~ 90 ℃ theoretically through expansion of expander, and the effect of temperature drop is much better than that of throttling. The reason is that the throttling process does not output work, and the decrease of temperature is caused by the increase of molecular potential energy.With the continuous increase of the flow rate of central extraction or circulation, the circulating temperature becomes lower and lower, the cold end of the switching heat exchanger becomes colder and colder, and the temperature in front of the expander still can not be increased. Finally, the adjustment means are lost, resulting in a passive situation. The reasons for this situation are: there is no proper restriction on the flow rate of central suction or circulation before liquid accumulation; the liquefier is connected late, or the liquefying effect of liquefier is poor;
DEAR Air separation equipment.The valve should be positioned before pipeline installation. The piping shall be natural and cannot be pulled hard in the wrong position to avoid prestress; the opening and closing test of low-temperature valve shall be conducted in cold state (such as in liquid nitrogen) as far as possible before positioning, and the valve shall be flexible without jamming;Due to these reasons, the temperature difference at the hot end increases, which will stabilize to a certain extent and will not continue to increase. The increase of the pressure difference before and after the heat exchanger is not necessarily due to the freezing of the heat exchanger. Because the molecular sieve in the purifier is broken, or the service cycle is too long, the powder filter at the outlet pipe is blocked, or the valve of the pipeline is too small, the pressure difference before and after the heat exchanger will increase.When the air passes through the throttle valve, the total enthalpy remains unchanged and the temperature and pressure decrease. As for whether liquid is produced before and after throttling, it depends on the state before throttling and the pressure after throttling. It can be seen from the thermodynamic properties of air that there is a saturation curve as the boundary of state.
