DEAR Cryogenic air separation unit.When the liquid level of condensing evaporator is too high, part of liquid oxygen can be discharged. This can not only make the liquid level drop rapidly, but also remove some impurities, which is conducive to safe operation. If the equipment is equipped with argon tower, the liquid oxygen level should be raised in advance to accumulate cold capacity, and then the argon tower should be started.Where the liquid layer is thin, the resistance is small, the amount of steam rising from the small hole is more; where the liquid layer is thick, the resistance is large, the amount of steam passing through is less, or even No. The distillation process of air on the fractionator tray depends on the mass transfer and heat transfer between the rising steam and the liquid on the tray. The more the gas and liquid contact on the tray, the more perfect the distillation process will be, and the more conducive to the separation of oxygen and nitrogen.DEAR Cryogenic air separation unit.The problem can't be solved by screwing the bolt alone. The bolt is often screwed hard because the leakage is not eliminated until the bolt is broken and the high-pressure gas in the pipe is ejected, causing personal injury. Therefore, it is necessary to strictly abide by the provisions of not screwing bolts under pressure, and not to rush for time and tasks with fluke mentality and violate the operating procedures.
The heating water in the heating furnace should be replenished in time, and the pressure of each part should not be greater than the working pressure when blowing. In the process of high and medium pressure blowing, the body is not allowed to aim at the gas outlet. Wear gloves when checking for impurities in the gas. Pay attention to the volume of air and whether the sound is normal.The operating pressure of medium pressure oxygen pipe network is generally 1.8 ~ 3.0MPa. When a branch pipe or spherical tank needs to be repaired, it will inevitably encounter the situation of medium pressure oxygen release and opening. In order to ensure the safety of opening and closing the oxygen valve, it is required to control the pressure difference between the front and back of the oxygen valve with diameter less than 50 mm below 0.3 MPa.Because the density of the vapor-liquid mixture formed in the boiling process is relatively small, the longer the tube is, the better the condensation heat release is. Generally, when l > 1.2m, the flow of condensate film has become turbulent.
If the air is compressed to 0.6MPa and the temperature is still 30 ℃, the saturated moisture content in each cubic meter of air is still 30.3g/m3. However, when the pressure increases, the air quality contained in each cubic meter of air increases, and the moisture content increases accordingly. When the temperature is constant and the saturation content is constant, the excess water will precipitate in liquid state.When other conditions are the same, the larger the average temperature difference is, the greater the heat transfer is, and the better the heat transfer effect is. For the same amount of heat transfer, the required heat transfer area can be reduced. The temperature of the heat flow in the same section of the heat exchanger must be higher than that of the cold fluid. If the downstream arrangement is adopted, the final temperature of the hot fluid outlet should still be higher than that of the cold fluid outlet;After positioning the vessel and valve, prepare the pipeline according to the actual situation. Don't force to install when the welding joint of valve and pipeline is too large; according to the field experience, generally, each welding joint shrinks about 1.5mm after cooling. For this reason, according to the specific situation of the installation welding joint at the flange connecting with the valve and vessel, the flange bolts shall be tightened without gasket before welding, and then the gasket shall be added after welding, so as to reduce the bolt pre tightening force and pipeline stress.
