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John Crane Gas Seal TechnologyCuts Costs, Emissions and Downtime
CUSTOMER NEED
• The company’s publicized commitment to the environment and meeting potential emission regulations were priorities.
• The upgrade needed to lower operating costs with short-term payback.
• Downtime from oil seal maintenance and replacements hurt production.
• Oil seal methane leaks cut deep into profits.
BACKGROUND
Industry: Natural gas processing
Site: Single compressor operation, process gas owned by equipment operator
Location: United States
End Product: Natural gas 85% methane
Equipment Utilization: 355 days a year
H Y P O T H E T I C A L C A S E S T U D Y : N A T U R A L G A S I N D U S T R Y S E R V I C E O F F E R I N G : T U R N K E Y U P G R A D E S E R V I C E F O R C E N T R I F U G A L
C O M P R E S S O R S H A F T S E A L S
HIGHLIGHTS
• Customer compared the three viable options to reduce methane emissions using John Crane’s Lifecycle Cost Calculator (LCC). (See lifecycle cost graph)
• Results from LCC showed gas processor could immediately beginsaving millions of dollars by upgrading from shaft oil seal to time-tested gas seal technology.
• These calculated savings are the result of reduced methane emissions, downtime and maintenance costs.
• Company confident of full compliance with potential environmental regulations regarding compressor emissions.
5 MONTHSScenario 1
Scenario 2
Scenario 4
Gas seal upgradepayback
11 MONTHSGas seal upgrade
ROI
7 MONTHSGas seal upgradepayback
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PROJECTED LCC ECONOMIC RESULTS
Calculated over 15 years, the total lifecycle cost of…
• Capturing the uncontrolled, vented methane and routing to a flare device is projected to be $20M.
• Capturing the uncontrolled, vented methane and routing for another purpose is projected to be $13M.
• Upgrading the oil seal to a gas seal is only $2M.
• Annual operating costs drop to just $73,000 compared to $1.4M with oil seals, representing more than $1.3M in savings.
• Product loss due to leakage estimated to drop to $31,000 — a $470,000 cost reduction from oil seals.
• Maintenance and downtime annual expenses are estimated to reduce to $30,000 — down $792,000 compared to oil seal.
• Methane leaked into atmosphere nearly eliminated, preparing the way for compliance with potential environmental and greenhouse gas legislation.
H Y P O T H E T I C A L C A S E S T U D Y : N A T U R A L G A S I N D U S T R Y
NATURAL GAS PROCESSING
• Assumes 1 compressor running approximately 100% utilization with the equipment operator owning the natural gas flowing through the compressor
• Centrifugal compressor with 2 seals running on a 5.52 shaft at 9,440 rpm and 470 psi
• Assumes methane content of 85% with a natural gas value of $2.86 per thousand cubic ft
• Assumes oil seal mean time between repair of 12 months
• Lost production due to oil seal maintenance estimated to be 200 hours per year
TECHNICAL SOLUTION
• Turnkey Upgrade Service for Centrifugal Compressor Shaft Seals, including as standard:
- Equipment audit and emissions baseline measurement
- Oil seal and system removal and disposal
- Custom gas seal solution (including rotor dynamics optimization and compressor modification if required)
- Installation and commissioning of narrow section gas seal, separation seals and gas seal system
- Emissions reduction monitoring
• Optional services include:
- Coupling change
- Bearing service
- Thermoplastic inter-stage labyrinth upgrade
$1.3 MILLION REDUCTION
ANNUAL OPERATING COSTS
- Replacement filters
- Dry gas seal management
0
Oil Seal Routed to Atmosphere
Oil Seal Routed to Flare
Oil Seal Routed to Capture/Use
Time (Years)
LIFECYCLE COST VERSUS TIME
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Cost
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)
Gas Seal
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15
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