For the first type, it is usually adjusted by changing the liquid level of evaporation side, that is, changing the size of heat transfer area. This regulation condition is relatively stable, and the pressure change of upper and lower tower is small. For the second type, when the liquid oxygen in the tube reaches 30% of the apparent liquid level, the churning condition can be established, and the heat transfer surface can fully play the role of heat transfer. Therefore, it can not be adjusted by changing the liquid level on the evaporation side.After cold blowing, the temperature decreases and a flat head peak appears. The longer the curve distance of the flat head peak is, the more water enters into the molecular sieve. In order to prevent the water inflow accident of Molecular Sieve Purifier, attention should be paid to the operation: the air cooling tower should be operated according to the operating procedures, first the gas is injected, and then the water is injected after the pressure rises and stabilizes; the gas volume should not be increased or reduced suddenly;
The extracted saturated liquid nitrogen is also at this temperature. The temperature of the liquid nitrogen is about 16 ℃ higher than that of the gas nitrogen in the upper tower. Therefore, when the two fluids flow through the liquid nitrogen subcooler, through heat exchange, the liquid nitrogen releases heat and is cooled into supercooled liquid, and the gas nitrogen becomes superheated steam due to heat absorption.DEAR Biogas purification unit.For equipment with acetylene adsorber, special attention should be paid to not too much gas flow through acetylene adsorber when blowing medium pressure. Therefore, when pulling out the stem of section-2 valve, the stem of section-3 and section-4 valve must be pulled out first, and the stem of section-2 valve cannot be pulled out alone for blowing.DEAR Biogas purification unit.Swirl plate. It consists of several swirling trays with metal structure. This kind of structure has little resistance and will not be damaged. It has been used as an improved one for quite a long time. But the heat transfer effect is not as good as packed tower. Sieve tray tower. The drenching tray with larger diameter and spacing is adopted. Both nitrogen and water pass through the screen. Because the water cooling tower does not work continuously and stably, the cooling effect is not ideal, so it is no longer used.
Before filling molecular sieve, check the sieve bed to avoid molecular sieve leakage, otherwise it should be treated. There should be no oil and other sundries in the tank; the filling personnel should not wear work shoes with nails to avoid stepping on the sieve bed; they should wear clean work clothes without oil. Several standard height marks should be made in the middle part. First check the ring chamber, fill the aluminum glue to reach the standard height, and then fill the molecular sieve.DEAR Biogas purification unit.Due to the impact of air flow, the actual content of carbon dioxide in the air at the cold end of the accumulator and the switching heat exchanger will exceed the saturation content, which will also affect the operation cycle. In particular, the cold section of the switching heat exchanger is too short, and the carbon dioxide precipitation zone is shortened, which makes it easier to bring part of carbon dioxide into the column, resulting in the increase of resistance of the distillation column, the weakening of main cooling heat transfer, the blockage of the subcooler, the increase of the down tower pressure, and the decrease of the air intake and oxygen output.
DEAR Biogas purification unit.Reduce the temperature after expansion. The lower the temperature after expansion, the greater the temperature difference with the positive air, and the stronger the heat transfer. Therefore, at this stage, the temperature after the expander should be controlled as low as possible without liquefaction, such as - 180 ～ + 185 ℃.DEAR Biogas purification unit.When installing the fractionator, attention must be paid to the two "vertical correction irons" on the outer side of the shell, and the verticality shall not be greater than 1 / 1000. If the fractionator is not installed vertically, it means that the tray is not horizontal. In this way, in the operation of the fractionator, the thickness of the liquid layer on the tray will be uneven, some places are thicker, some places are thinner, and some places even have no liquid.The reflux liquid needed for distillation is the liquid partially condensed in the condenser from the rising gas. The cold source is throttled liquid nitrogen, part of which comes from the main tower and part from the liquid nitrogen condensed in the bottom evaporator. The refined argon product can be extracted in liquid form, or it can be pressurized to recover the cold capacity and then filled into the bottle.
