DRY GAS SEAL

WHAT IS “ DRY GAS SEAL “ ?

- Gas-lubricated

- Used for twenty years ago

- Almost of the compressor use them

THE BENEFIT OF DRY GAS SEAL

- Reduce leakage gas process

- Reduce the complex of system support

- Reduce failure of mechanical system

- Reduce amout of seal oil

SEAL GAS SYSTEM

WHY USE TANDEM SEAL SYSTEM ?

- There are many seal systems: primary seal gas, secondary

seal gas and separation seal gas

- Prevent process gas leak from secondary seal, allowing

vent to atmosphere

- High safety

DRY GAS SEAL HANDBOOK

THE CONFIGURATION OF TANDEM SEAL GAS

TANDEM SEAL SYSTEM

• Primary seal : Absorb the pressure drop and vent to atmosphere

• Secondary seal: as beck-up seal of primary seal gas

• Separation seal : prevent lube oil entering the seal gas

• Barrier Seals : Tách biệt seal gas với shaft bearing, ngăn ngừalube oil đi vào gas seal, đồng thời cũng là vách ngăn cuối cùngkhi primary và secondary seal bị phá vỡ

DRY GAS SEAL HANDBOOK

YÊU CẦU

• Ap suất lớn hơn áp suất yêu cầu ở điểm kết nối 50 psi

• Không có hạt rắn có kích thuớc lớn hơn 10 micron

• Hạn chế tối thiểu luợng liquid trong khí

• Giữ nhiệt độ cao hơn nhiêt độ dew point tối thiểu 200 F

• Tốc độ dòng seal gas tôi thiểu 32 ft/s

DRY GAS SEAL HANDBOOK API Standard 614

DRY SEAL GAS IN DQR ( WET GAS COMPRESSOR )

VENDOR DOCUMENT

VENDOR DOCUMENT

VENT

• Sử dụng chênh áp xác định độ rò rỉ khí seal

• Dấu hiệu nhận biết leakage: Lưu lựong dòng khí lớn + độchênh áp qua orifice lớn

DRY GAS SEAL HANDBOOK

DRY GAS SEAL HANDBOOK

DRY GAS SEAL HANDBOOK

WarningPDI > 70 psi

API 614 ( page 71 , 75)

RequireB3 > 75

QUESTION AND ANSWER

DRY GAS SEAL HANDBOOK

Why flow rate of seal gas is controlled by different pressure controller ?

WHY PRIMARY SEAL GAS IS DRAINER CONTINUOUSLY WATER BUT THE SECONDARY SEAL GAS ISN’T ?

WHY OUTLET OF PRIMARY SEAL GAS IS VENTED TO FLARE BUT SECONDARY SEAL GAS IS VENT TO ATMOSPHERE ?

WHY NEED TO HEAT TRANCING WITH ONLY PRIMARY SEAL GAS ?

WITH SECONDARY SEAL GAS, WHY DON’T NEED TO HAVE A TRIP ALARM ?

SUMMARIZE

• Three seal: primary seal, secondary seal and separation seal

• Requirement on Seal Gas

• Realize problems

LINK DOWNLOAD

• DRY GAS SEAL HANDBOOK : http://tinyurl.com/DRYGASSEAL

• API Standard 614 :

http://tinyurl.com/API614

THANK YOU

FOR LISTENING

DISCUSSION

• When primary seal gas is normal, but secondary seal gas has problem, what should we need ?

• Method ?