The Peking University Pioneer Pressure Swing Adsorption Oxygen Plant is composed of an air blower, vacuum pump, oxygen adsorption tower, product storage tank, pressure equalization buffer tank, and pipeline programmable valves. It is controlled by computer programs and driven by oil pressure to separate oxygen products from the air. This article focuses on the common 4000m3/hPeking University Pioneer Pressure Swing Adsorption Oxygen PlantFor example, introduce the equipment composition and characteristics of the device.

1、 Main equipment

1. Inlet air filter

The inlet air filter consists of two layers of filter screens, inner and outer, used to remove mechanical impurities from the air. The set differential pressure gauge is used to display whether the filter should be maintained.

2. Centrifugal raw material air fan and vacuum fan

The raw material fan used in this device is a 2057-RAS-JV Roots blower, which is used to supply air to the adsorption bed. Design flow rate of 50000m3/h; The vacuum fan is a 2070VJ-V Roots blower, which provides vacuum for the regeneration of adsorbents and the discharge of exhaust gas, with a designed flow rate of 65500m3/h. Two fans are jointly driven by an electric motor with a power of 2235kW. A sealing water system is also installed inside the vacuum fan to provide sealing, lubrication, and cooling functions.

3. Sealed water system

The sealing water is sent from the equipment rack to the inlet pipeline of each level of vacuum fan. The pressure is controlled through a pressure regulating valve. When the vacuum fan is running, open the shut-off valve to supply sealing water, and close the valve when stopping. When the inlet valve is open, the drain valve is closed. When the inlet valve is closed, the drain valve opens to release pressure from the inlet valve and ensure that no water is sent to the vacuum fan. The sealing water flow rate of each level is controlled by a flow regulating valve. When the water flow rate of any level is lower than the set value of the flow switch, it will cause parking.

During normal operation, the sealing water is carried by the waste nitrogen gas to the vacuum separation muffler for discharge. When the vacuum fan stops, the remaining moisture is discharged from the discharge pipeline back to the equipment rack. When the vacuum fan is running, the drain valve is closed, and when the fan is stopped, the drain valve is opened.

4. Dual adsorption bed

The double adsorption bed is equipped with 13X and specialized pressure swing adsorption oxygen molecular sieve adsorbent. 13X and pressure swing adsorption oxygen molecular sieves are used to adsorb moisture, carbon dioxide, hydrocarbons, and nitrogen in the air, respectively. Two types of adsorbents are radially distributed in the bed, reducing the impact of axial airflow on the molecular sieve. The top of the molecular sieve is sealed and compressed with a rubber film to prevent the molecular sieve from moving up and down. At the same time, protective oxygen with a pressure of about 15PSIA (1PSIA=6.89476kPa) is introduced into the protective layer. A steel plate is used at the bottom to block the air and allow it to rise, and then evenly enter the molecular sieve from the side. Steel wire mesh is used to prevent radial movement of the molecular sieve.

5. Automatic switching valve

It has significant advantages of cutting more than 1.5 million times.

6. Instrument compressor system

The VPSA system uses an instrument compressor and a matching dryer to provide instrument air. The power of each unit is 37kW, which can provide 3.8m3/min of air volume for the system. The air supply system can be controlled using the factory's air pipeline network.

7. Programmable Logic Controller (PLC) system

The complete VPSA system is equipped with DMACS operating program, which allows access to the control system's operating interface (OIU) through the DMACS operating platform software. The computer system does not affect device operation even in the event of a PC crash; And under the condition of communication *, it is possible toControl can be achieved remotely by connecting to a computer anywhere, with basic unmanned operation.

8. Auxiliary equipment for fans

The auxiliary equipment of the fan includes inlet and outlet mufflers, vacuum separation mufflers, and exhaust emission mufflers. The separation muffler is used to separate the exhaust gas and sealing water from the outlet of the vacuum fan. The exhaust gas is directly discharged into the atmosphere. The sealed water is discharged into the collection well to serve as a nitrogen seal.

9. Oxygen compressor system

According to VPSA's oxygen production and user requirements, vertical, two-stage, and three column piston compressors can be selected. The displacement of each oxygen compressor is 5000m3/h, and the rated outlet pressure is 0.8MPa.

2、 Characteristics of the device

1. Advantages

Compared with the traditional cryogenic air separation method for oxygen production, this 4000m3/h pressure swing adsorption oxygen production process has the following advantages:

1) VPSA oxygen production starts quickly (in about half an hour).

2) The construction period is short and the investment is low, which is about 75% of the investment in low-temperature oxygen concentrators with the same output.

3) Less land occupation. A single VPSA occupies a net area of approximately 300m2.

4) Low energy consumption. The electricity consumption per cubic meter of oxygen is only 0.33kW. h.

5) Strong adaptability to load changes, adjustable within the range of zero to full load.

6) Can achieve pause. Pause can be achieved when the user's oxygen consumption decreases or oxygen is not used for a short period of time, allowing the equipment to operate in an energy-saving state, greatly reducing energy consumption and fluctuations in the power grid, as well as damage to the equipment caused by starting and stopping.

7) The degree of automation is high, and oxygen production can be basically automated.

8) There are fewer operators, 50% fewer than those in the cryogenic oxygen production position.