Background of Plateau Tunnel Oxygen Generators

The Qinghai-Tibet Plateau region suffers from severe oxygen deficiency and a fragile ecological environment. During the construction of long tunnels, to improve the working conditions inside the tunnels and ensure the physical and mental health of workers, it is necessary to set up plateau pressure swing adsorption oxygen generation stations near the tunnel entrances. This oxygen production and supply system employs the pressure swing adsorption method, relying on the differences in the adsorption capacity of solid adsorbents for various components of air and the characteristic that adsorption capacity changes with pressure to separate air, producing and collecting oxygen. The oxygen generated by the oxygen generator is filled into oxygen cylinders; tunnel oxygen bar vehicles provide centralized oxygen supply. When necessary, diffuse oxygen supply can be directly applied to the tunnel face.

Composition of the Plateau Tunnel Oxygen Generator

The oxygen generator consists of an air compressor, subcooler, adsorbers, gas storage tanks, instruments, switching valves, and other components. Two adsorbers are installed, equipped with airflow equalizing ceramic balls and oxygen-generating molecular sieves to ensure continuous oxygen supply. The entire oxygen generation process, including adsorption, depressurization, venting, purging, and pressure equalization, is fully automated and controlled by a PLC.

Raw air passes through a filter to remove mechanical impurities before entering the compressor. The raw air is compressed to 300 kPa in the compressor and then enters the subcooler for cooling. The cooled compressed air then enters the adsorbers.

Process Flow of the Plateau Tunnel Oxygen Generator

To ensure continuous oxygen supply, this device is equipped with two adsorbers, containing airflow equalizing ceramic balls and oxygen-generating molecular sieves. One adsorber takes in raw air from the bottom and produces oxygen from the top, with the product gas flowing into the oxygen buffer tank. The other adsorber is in the regeneration phase, where desorbed nitrogen is released into the atmosphere, restoring the adsorption capacity of the molecular sieve.

The two adsorbers alternate between adsorption and desorption. Each adsorber must complete steps such as adsorption, pressure equalization, reverse purging, and desorption in every cycle.

The tunnel oxygen generation and supply system consists of air pretreatment, air compression system, adsorption separation system, oxygen compression system, tunnel diffuse oxygen supply device, and tunnel oxygen bar vehicles.

Workflow of the Filling Operation System for the Plateau Tunnel Oxygen Generator

The oxygen produced by the oxygen generator is compressed to 10 MPa by an oxygen compressor and then delivered to the filling station. The main task of the oxygen filling station is to fill the high-pressure oxygen produced by the oxygen compressor into medical oxygen cylinders. These cylinders come in various specifications, such as 2L, 3L, 4L, 10L, and 40L, for tunnel construction workers to carry with them or for personal use after being filled into medical oxygen cylinders.