Ultra-low discharge pressure

I. Preface With the rapid development of industry, nitrogen has been widely used in chemical engineering, electronics, metallurgy, food, machinery and other fields. The demand for nitrogen in our country increases at a speed of more than 8% every year. The chemical property of nitrogen is not active, and it shows great inertia under normal conditions, so it is not easy to react with other substances. Therefore, nitrogen is widely used as protective gas and sealing gas in metallurgical industry, electronic industry and chemical industry. Generally, the purity of protective gas is required to be 99.99%, and some require high purity nitrogen of more than 99.998%. Liquid nitrogen is a relatively convenient cold source, which is more and more widely used in food industry, medical service and the seminal storage of animal husbandry. During the production of synthetic ammonia in the chemical fertilizer industry, if the mixture of hydrogen and nitrogen, the feed gas of synthetic ammonia, is...

The start-up phase of the whole low-pressure oxygen generator is that liquid empty appears first in the lower tower, and then liquid oxygen appears in the upper tower. The cold energy needed to accumulate liquid in the tower mainly comes from the expansion machine, which uses the low temperature gas after expansion to make part of the air liquefaction in the liquid purifier. But the upper tower itself can not produce liquid, it mainly depends on the liquid from the lower tower into the upper tower. In the phase of hydrops, in order to accumulate the liquid level as soon as possible, the cooling volume should be transferred to the tower as much as possible, the phenomena of overcooling, temperature difference at the hot end and cold loss increase caused by excess cooling of switching heat exchanger should be avoided. As for how to recycle and transfer the cold volume of the air expansion into the tower, whether it is by the liquid purifier to transfer the cold volume to the lower tow...