Generally, the amount of hydrogenation should be increased by 1% excess hydrogen according to the amount of hydrogen required for complete reaction of hydrogen and oxygen. The purpose is to make the oxygen in the crude argon react fully and further improve the purity of the refined argon. According to the calculated amount of hydrogenation and start hydrogenation, the process should be slow.When there is liquid in the storage tank, it is strictly forbidden to use hot work for repair; the thawing of equipment pipeline should be heated slowly, and do not use overheated working medium or open fire to thaw; protective gloves should be worn when contacting low-temperature liquid to avoid direct contact between skin and low-temperature liquid; the transportation process should be stable, and there should be no big bumps.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.
In the installation, there should be a firm support at the valve to prevent the valve from bending the valve stem with the displacement of the pipeline. The valve and the cold box can be fixed by elastic connection to prevent the valve rod from being deformed and not concentric with the valve body; during the naked cold period, the valve installation should be checked and adjusted in the cold state.DEAR Liquid air separation unit.When the unit is in normal operation, the cooling capacity is mainly to balance the cooling capacity loss of the unit and the cooling capacity needed to produce a small amount of liquid products. Generally speaking, according to the design conditions, an expander can meet the requirements. When an expander can not maintain normal liquid level, there must be abnormal cooling loss such as internal leakage. At this time, it can't solve the fundamental problem to increase the refrigeration capacity only by increasing the expander. But we should first find out the reason for the increase of cooling loss.
After the pipelines, valves in the tower and the air separation units installed on site are completely installed, heated and purged, the start-up refrigeration is carried out without filling the cold insulation material in the cold insulation box, which is called "bare cooling". Therefore, bare cooling is an indispensable process for the equipment installed on site, after installation and before formal test run, which should be given enough attention.The common fault of the automatic valve is that it is not closed tightly, resulting in gas channeling at the middle and low pressure cold end. This is reflected by the increase of air flow and the decrease of pressure. At the same time, the pressure of the low pressure system increases. The failure of automatic valve is also a great threat to the normal production of oxygen generator.DEAR Liquid air separation unit.The equipment that transfers heat from hot fluid to cold fluid is called heat exchanger, or heat exchanger. There are many heat exchangers in the air separation plant, including nitrogen water precooler, switching heat exchanger (or cold accumulator), main heat exchanger, condensing evaporator, subcooler, liquefier, gasifier, heater and air compressor cooler.
In this way, continuous refrigeration can be realized. In the oxygen generator, it is also a refrigeration process to reduce the air temperature to the liquefying temperature. Therefore, there must be a compressor at the cost of power consumption. Only in the oxygen generator, air is used as the working medium, and the purpose of cooling is achieved by first compressing and then expanding the air. Then cool the air itself until it reaches the liquefying temperature.DEAR Liquid air separation unit.The situation at the top of the distillation column is similar to this, gas nitrogen and liquid nitrogen are in the coexistence of saturation state, with the same saturation temperature. However, the saturated liquid and vapor at the same temperature belong to different states. The heat released by saturated steam can be condensed into saturated liquid with constant temperature, which is called "condensation latent heat"; the heat absorbed by saturated liquid can be gasified into saturated steam with constant temperature, which is called "evaporation latent heat". For the same substance, under the same pressure, they are equal in value.
