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I. Process description: 1. Description of the primary sealing gas process: During normal operation, the outlet gas from the compressor (10.5 MPa.A) is used； At 80 ℃ and 30 μ), this gas is used as the source of gas for the primary seal; it enters the sealing system through the G1 flange port, is filtered by the F1, F3 (or F2, F4) filters, and then the pressure behind the valve is adjusted to be about 0.2 MPa higher than the pressure in the compressor balance line using the PDV-2882 pneumatic diaphragm control valve. Subsequently, this gas enters the high-pressure and low-pressure primary seal chambers via the flow-limiting orifice plates SO8 and SO7, respectively. When starting up or shutting down the compressor, purified hydrogen at 10.5 MPa.A can be used ； 80 ℃, 30μ) can be used as a temporary source of gas for the primary seal; nitrogen at 1.6 MPa can also be employed as a temporary source of gas for the primary seal (in this case, the pressure in the compressor’s balance line must not exceed 1.5 MPa) ； The process is the same as before… The main function of the primary seal gas is to prevent unclean gases inside the compressor from contaminating the primary seal surface. As the compressor rotates at high speed, this gas is pumped into the primary seal flare chamber through the spiral grooves on the seal surface, thereby creating an air film between the surfaces that serves to lubricate and cool them. The vast majority of this gas enters the machine through the labyrinth at the compressor’s shaft end, with only a very small portion entering the primary seal flare chamber through the primary seal end face. 2. Description of the secondary sealing gas and rear isolation gas flow: Low-pressure nitrogen at room temperature and 0.6 MPa.G is used as the source for both the secondary sealing gas and the rear isolation gas. After entering the system through the G2 flange port, this gas passes through filter F5 (or F6) before flowing into the high-pressure and low-pressure secondary sealing chambers as well as the rear isolation sealing chamber respectively: 1) It enters the low-pressure side secondary sealing chamber after being throttled and depressurized by the orifice plate assembly S03 ； 2) It enters the secondary sealing chamber on the high-pressure side after flow restriction and pressure reduction via the orifice plate assembly S04 ； The main function of the secondary seal gas is to prevent the small amount of medium gas that leaks from the primary seal surface from entering the secondary seal surface, thereby ensuring the safe and reliable operation of the secondary seal. Most of this gas, along with the small amount of medium gas that leaks from the primary seal surface, enters the flare line through the flare chamber of the primary seal; only a small portion of the gas enters the secondary seal vent chamber through the secondary seal surface, where it is then vented along with some of the backpressure isolation gas. 3) After flow restriction and pressure reduction via the orifice plate assembly S01, it enters the low-pressure rear isolation seal chamber ； 4) After flow restriction and pressure reduction via the orifice plate assembly S02, it enters the high-pressure rear isolation seal chamber ； The main function of the rear isolation gas is to ensure that the secondary sealing surface is not contaminated by the lubricating oil vapor from the compressor bearings. Part of this gas is vented at a high point along with the small amount of nitrogen that leaks from the secondary sealing surface, while the other part is vented through the rear sealing comb teeth via the breathing cap. 3. Process description for the flare pipeline: Most of the nitrogen that enters the secondary sealing chamber mixes with the small amount of gas that leaks from the primary sealing surface, and then this mixture enters the high-pressure and low-pressure end sealing flare systems via the B1′ and B2′ flange ports, before passing through FT-2881 and G3 ； FT-2882 and G4 enter the site to the flare pipeline. II. Operating procedures: After the dry gas seal system is installed, before mounting the seal body, clean instrument air or low-pressure nitrogen at a pressure of 0.4–0.6 MPa should be supplied through the G1 and G2 flange ports for continuous purging for 4–6 hours or more. This process should continue until a fine cloth is placed against the outlet and blown therefor for more than 5 minutes; if no dust, oil, moisture, or other impurities can be detected upon close inspection, then the system is considered qualified. After purging, close all valves and put it in standby mode. 1. Open all normally open pressure tapping valves in the system, and activate on-site pressure gauges, transmitters, etc. 2. At least ten minutes before the start of oil transportation, please introduce the backpressure isolation gas, and then turn on V8, V9 (or V10, V11) in sequence ； For the upstream and downstream valves of the S01 and S02 sonic orifice plate assemblies, isolate gas is supplied after they are put into operation. Similarly, the rear isolation gas can only be turned off after the oil transport has stopped for ten minutes and there is no oil flow in the return oil pipeline. 3. Before introducing process gas to the compressor or conducting a leak test, primary sealing gas should first be supplied. Open valves V6, V5, V2, V1 (or V4, V3) in sequence to introduce the primary sealing gas source, and set PDICA-2882 to 0.2 MPa in the control system at the control room ； On-site observation shows that the reading of pressure gauge PI-2882 should be 0.2 MPa higher than the pressure in the balance line. When the compressor is shut down, the inlet to the primary seal can be closed only after all gas inside the machine has been exhausted. 4. After the primary sealing gas is put into use, activate the flare or high-point vent line, and then introduce the secondary sealing gas. Open valves V14, V18, V15, and V19 respectively to activate the flare lines for the primary seal discharge chamber ； Subsequently, the upstream and downstream valves of the SO3 and SO4 orifice plate assemblies were opened to introduce air under high and low pressure for secondary sealing. 5. Set the upper and lower limit alarm values for the flow rate of the primary seal discharge pipelines at the high and low pressure ends of FIA-2881 and 2882 on the control system in the control room, as well as the interlock value for the high-limit alarm of the pressure switch (three-out-of-two) ； PDIA-2881: Upper limit alarm value for the differential pressure of the primary seal filter; PDICA-2882: Lower limit alarm value for the differential pressure between the primary seal gas and the balance tube, etc ； As well as the settings for starting the machine and interlock shutdown conditions, etc. (see the alarm and interlock condition logic diagram).