Apparatus and method for preparing pressure nitrogen gas with air separation

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 an air separation device and a method for producing pressure nitrogen. Background technique [0002] In the process of float glass production, a large amount of nitrogen is needed as a protective gas, the gas pressure is 0.15-0.4MPa, and the nitrogen purity is ≤3ppmO 2 . At the same time, a small amount of liquid nitrogen (≤5% nitrogen output) is required for backup. Therefore, in float glass production enterprises, there are generally attached devices for air separation and pressure nitrogen production. An air separation device in the prior art for pressure nitrogen production uses single-tower reflux enriched oxygen (exhaust gas) to expand nitrogen production, and its energy consumption is 0.28-0.35KWh / NM 3 N 2 . Another device for producing pressurized nitrogen by air separation is to use air expansion single tower to produce nitrogen. The nitrogen pressu...

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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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