The steps of adjusting the argon output are as follows: 1) adjusting the balance of air separation cooling capacity to increase the cooling capacity of argon system; 2) adjusting the working condition of main tower to increase the amount of argon fraction; 3) adjusting the working condition of crude argon tower to increase the amount of crude argon; 4) adjusting the working condition of refined argon tower to increase the argon output.DEAR Cryogenic air separation unit.The unit of entropy is J / (mol · K) or kJ / (KMOL · K). However, what we usually care about is not the value of entropy, but the change trend of entropy. For the actual adiabatic expansion process, the entropy must increase. The smaller the increase of entropy, the smaller the loss and the higher the efficiency.DEAR Cryogenic air separation unit.The inspected parts include: expander outlet valve, medium pressure safety valve, joint of acetylene adsorber safety valve, lower tower, acetylene adsorber heating valve and its blow off valve, upper and lower valves of liquid air level gauge, liquid nitrogen, liquid air analysis valve, neon helium blow off valve, high pressure air throttle valve and sealing packing of on-1 valve. After the air leakage is eliminated, the pressure can be increased continuously.
DEAR Cryogenic air separation unit.For a certain location, the oxygen content in the air is basically unchanged. When the amount of air entering the tower and the purity of product oxygen are constant, the oxygen extraction rate depends on the amount of oxygen output. The amount of oxygen production, for the full low pressure oxygen generator, under the condition of a certain amount of air intake, mainly depends on the level of oxygen in the sewage nitrogen. Taking 3200m3 / h air separation unit as an example, when the inlet air is 18100m3 / h, the amount of nitrogen in waste gas is 60.2% of the amount of processing air, and the volume fraction of oxygen in waste nitrogen is 5.5%, the oxygen output is 3200m3 / h, and the oxygen purity is 99.6%. It can be calculated that the oxygen extraction rate is ψ = 3200 × 99.6 / (18100 × 20.9) = 0.842, that is 84.2%.It can be seen that in the air separation plant, throttle valve and expander have their own advantages and disadvantages, and they are used together to meet the requirements of refrigeration capacity. The refrigeration capacity is adjusted by adjusting the refrigeration capacity of the expander, and the lowest temperature (- 193 ℃) in the air separation tower is achieved by liquid throttling.
Attention should be paid to the following problems when using: the liquid level in the liquid oxygen tank should not be lower than 20% at any time; the acetylene content in the liquid oxygen in the tank should be analyzed according to the specified period (for example, once every half a month), and measures should be taken to solve the abnormality in time; the liquid in the tank should not be stored for a long time, and should be filled and discharged frequently, so as to avoid the concentration of acetylene and other harmful impurities.DEAR Cryogenic air separation unit.It should be noted that the refrigeration capacity of the expander is not only related to the expansion capacity, but also related to the inlet and outlet parameters of the expander. The total cooling capacity of two expanders may not be as large as that of one expander at full load. For example, if an expander with an expansion capacity of 2700m3 / h operates under the following conditions: P1 = 0.55mpa, T1 = 123k; P2 = 0.125mpa, T1 = 85K, the unit cooling capacity is △ H = h1-h2 = 8270 (kJ / KMOL) - 7264 (kJ / km01) = 1006kj / KMOL.
）The enrichment of argon in the upper column is not constant. When the purity of oxygen and nitrogen products changes, the distribution of argon in the upper column will change, and the composition of argon fraction will also change. The change of oxygen purity is more sensitive to the composition of argon fraction. When the oxygen purity changes by 0.1%, the argon content of argon fraction will change by 0.8% ~ 1%. With the increase of oxygen purity, the argon rich region will move up and the argon content of the fraction will decrease.DEAR Cryogenic air separation unit.Our common refrigerators and air conditioners obtain low temperature by refrigeration process. It must consume electricity to drive the compressor. The material circulating in the refrigerator is called "refrigerant". It is a low boiling point substance, commonly used are ammonia, freon, etc.DEAR Cryogenic air separation unit.We should give full play to the refrigeration capacity of several expanders, rationally distribute and utilize the cooling capacity, and shorten the start-up time by relying on the potential of the equipment itself. Because of the large heat capacity of the stone accumulator, it takes quite a long time to cool down to normal temperature after heating. The air from the turbine air compressor can be used to blow the packing close to the normal temperature before starting the expander, and the hot air can be discharged from the automatic valve box. This can shorten the precooling time of packing.
