Device and method for separating pressized nitrogen gas from air

Abstract

The invention relates to a device separating the air to produce the pressurized nitrogen, and comprises a pressurized turbine inflation machine, an air cooler, a main heat exchanger, a low-pressure tower, a re-boiler that is arranged inside the low-pressure tower, a low-pressure tower condensation evaporator, a high-pressure tower, a high-pressure tower condensation evaporator and a sub-cooler, wherein, the low-pressure tower and the high-pressure tower are arranged in the same cooling box side by side. Each device is connected with each other through a connection pipe. The invention relates to a method for separating the air to produce the pressurized nitrogen, which adopts the following steps: the raw material air enters into the pressurized turbine inflation machine to be inflated and cooled, and flows into the low-pressure tower to be rectified and separated, so that the high-pressure nitrogen can be obtained at the top of the high-pressure tower and is adopted as the finished product to be outputted. Adopting the device and the method, the nitrogen extraction rate can reach 78 to 86 percent; compared with the single-tower air inflation nitrogen production, the electricity consumption of the unit product can be reduced by 17 percent; compared with the dual-tower waste-gas inflation refrigeration flowing procedure (dual-tower return flow), the electricity consumption can be reduced by 10 to 15 percent.

Description

technical field [0001] The invention relates to a gas separation device and a separation method, in particular to a device and method for preparing pressure nitrogen by air separation. Background technique [0002] In the production process of float glass, a large amount of nitrogen needs to be used as protective gas, the gas pressure is 0.15-0.4MPa, and the nitrogen purity is less than or equal to 3ppmO 2 . At the same time, a small amount of liquid nitrogen (≤5% nitrogen production) is required for backup. Therefore, in float glass production enterprises, a device for producing pressure nitrogen by air separation is generally attached. A device for producing pressure nitrogen by air separation in the prior art adopts single tower reflux oxygen-rich (waste gas) expansion to produce nitrogen, and its energy consumption is 0.28-0.35KWh / NM. 3 N 2 . Another device for producing pressure nitrogen by air separation is to use air expansion single tower to produce nitrogen. Th...

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Problems solved by technology

The double-tower nitrogen waste gas expansion refrigeration (double-tower reflux) process increases the oxygen content of the liquid air entering the low-pressure tower through the high-pressure tower purification, but because the heat source of the low-pressure tower reboiler is nitrogen at the top of the high-pressure tower, the high-pressure tower The pressure is increased due to the heat transfer temperature difference, so that the energy consumption of nitrogen production cannot be further reduced

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