| 摘要 |
<p>PURPOSE:To make it possible to cope with the variation of a demand quantity quickly by a method wherein an expansion turbine and the feeding of liquid nitrogen from a liquid nitrogen storage means are operated in parallel, and the liquid nitrogen feeding quantity from the liquid nitrogen storage means is controlled, and the liquid level of liquid air in a dephlegmeter is controlled to be uniform. CONSTITUTION:A dephlegmeter 15 in which a condenser is built in is provided at an upper part of a fractionator 10, and one part of gaseous nitrogen in the fractionator 10 is always guided into the condenser to liquefy the gaseous nitrogen, and after liquefied nitrogen is accumulated to a specified quantity, the liquid nitrogen which is formed after that is always returned to the fractionator 10 as a circulating liquid. That is, a specified quantity of product gaseous nitrogen is prepared by always operating an expansion turbine, and in addition, a fluctuated portion of demand is compensated by liquid nitrogen from a liquid nitrogen storage tank 7. Even when a variation is generated in the demand quantity of the product gaseous nitrogen, the opening degree of a valve is controlled by a control means, and the feeding quantity of liquid nitrogen to the fractionator 10 is controlled, and thus, the liquid level of liquid air in the dephlegmeter 15 is controlled to be uniform, and therefore, the title device can cope with the variation of demand quantity quickly.</p> |
