PUMPING OF MOLTEN SULPHUR - Calgary Pump · PDF filePUMPING OF MOLTEN SULPHUR PRESENTER TOM...

PUMPING OF MOLTEN SULPHUR

PRESENTER

TOM STILES P. ENG

Calgary Pump Symposium 2015 1

2CALGARY PUMP SYMPOSIUM 2015

• PresenterPresenter Name:Tom Stiles

Bio: Mechanical Engineer45 Years of Pumping Experience35 Years of Sulphur Pumping Experience

Involved in Over 300 Successful Installations in Canada, USA, Chile, China, India, Malaysia, Mexico, and the Middle East.


SULPHUR AS A SOLID


SULPHUR AS ALIQUID


MOLTEN SULPHUR TRANSPORT

Solid Under Normal Atmospheric ConditionsColour – Lemon Yellow---------------------------------------------------------------Melts At Approx. 118 CColour – Red, Orange, Yellow CombinationGood Lubricating Liquid – Non Corrosive, Non AbrasiveViscosity 7 – 12 CPS, S.G 1.8

Caramelizes At Approx. 156 CThus, We Must Control The Temperature Between 118 and 156 C.

Impurities can raise the Caramelizing Temperature as High as 177 C. Customer Must Specify Based on Actual Experience.

Very Important Property: Sulphur Is a Very Poor Conductor of Heat.


SULPHUR ITSELF

• WHERE MOLTEN SULPHUR PUMPS ARE USED

• Oil Refineries – Stack Gas Emissions

• Mining – Sulfide Mineral Ores

• Sour Natural Gas and Oil

• Sulfur Re-Melt Piles

• Truck or Rail Car Loading and Unloading



• TYPES OF PUMPS USED

VERTICAL

VERTICAL CANTILEVER SHAFT

VERTICAL TURBINE

HORIZONTAL

1) CENTRIFUGAL

API 610, ANSI, OR SUMP PUMP BASED

• TYPES OF PUMPS USED CONTINUED


2) POSITIVE DISPLACEMENT

ROTARY GEAR OR LOBE

USUALLY SOLD ON AN EXPENDABLE BASIS

SOMETIMES SUBMERGED


HORIZONTAL CENTRIFUGAL PUMP


VERTICALCENTRIFUGAL PUMP


ROTARY POSITIVE DISPLACEMENT PUMP

API 610 VERSUS ASME B73.1 & .2

ANSI FOR PRESSURES UP TO 150 PSIGFASTER DELIVERY AND ABOUT ¼ PRICE OF APIMORE MANUFACTURERS WITH VAST EXPERIENCE

API FOR PRESSURES ABOVE 150 PSI

API WHERE SPECIFIED


METHODS OF TEMPERATURE CONTROL / HEATING

JACKETING OR HEAT TRACING

HEATING MEDIUMS FOR JACKETING

STEAM – BY FAR THE MOST COMMON

GLYCOL

HOT OIL


VERTICAL MOLTEN SULPHUR PUMPSNON API 610 VERSIONS

SIMILARITIES:

- JACKETED COLUMNS AND DISCHARGE PIPES- (JACKETING IS THE KEY TO TEMPERATURE CONTROL)

- USUALLY USE 2” OR 2.5” DIA. SHAFT DESIGN

- USUALLY DRY RUNNING PACKED STUFFING BOX

- VERY SIMILAR EXTERNAL APPEARANCE



OTHER COMMON FEATURES:

ASME Section Vlll Jacketing Fully Hydrotested

CRN Numbers for Projects in Canada

Oversized Discharge Pipe to Keep Velocities Below 10 feet/sec.

Heavy Duty Thrust Bearings Now Supplied As Standard

Usually Packed Stuffing Box (With No Lubrication), Rarely Mechanical Seals – Either Double Mechanical Seals with Flush Plan 53, or Gas Seals with Gas Panel

VERTICAL MOLTEN SULPHUR PUMPSNON API 610 VERSIONS

DIFFERENCES:- PLACEMENT OF JACKETING- HOW SLEEVE BEARINGS ARE HELD IN PLACE- MATERIALS OF SLEEVE BEARINGS – CARBON, NIRESIST, GRAPHALLOY

- HOW SLEEVE BEARINGS ARE LUBRICATED- HOW COLUMNS ARE DRAINED- MATERIAL OF DRY RUNNING PACKING



Conventional ShaftBearing TypeVertical JacketedPump

Cantilever ShaftVertical JacketedPump


• MORE FACTS ABOUT VERTICAL MOLTEN SULPHUR PUMPS

• Most Common 2” and 2.5” Dia. Shaft Designs

• Using 2” dia. Shaft Design As An Example• In order to stay below first critical speed, can have a max.

bearing span of 63” at a speed of 1800 RPM• One or Two bearing span pumps are most reliable and • provide the longest life between overhauls – Up to 10 years.• Three bearing span pumps average 3 to 5 years between

overhauls.• Four bearing span pumps give approx. 2 years from factory, less

than 1.5 years when repaired in the field.• Avoid long pumps!• For continuous operation, some manufacturers use one bearing

span of 75” to 90” and operate between first and second critical speed.

• Avoid this!


SPEEDUsually 1750 RPM on 60 Cycle Power, 1450 RPM on 50 Cycle PowerSeldom V-belt Driven to Intermediate SpeedVFD’s Becoming More CommonSometimes 2900 RPM on 50 Cycle Power – Poorer But Not Bad!Sometimes 3500 RPM on 60 Cycle Power – Poorer Still!Occasionally 1150 RPM (950 RPM on 50 Cycle Power) – Wonderful!

We Recommend the Lowest Speed Practical to Handle the Application!

• The Most Common Problem• Too Hot, Not Too Cold

• Temperature Must be Maintained at 138 C• If Using Steam, Use 35 PSIG Steam

• Up to 15 Degrees of Heat are Generated By the Sleeve Bearings of a Vertical Molten Sulphur Pump.

• Symptoms of Too Hot• Pump Runs, Motor Overloads and Cuts Out, Pump Left

for a Few Minutes, Then Started Again. Cycle Repeats Over and Over.

• Also Watch For Too Little Flow Through Pump. Often Minimum Flow Bypass is Used.


• 4) Velocity Freezing

• When Drawing Down Near Liquid Level

• With Sulphur Temperatures Below 127 C

• In Suction Strainers


• Contaminated Sulphur• (i) Water• From Steam or Groundwater• Do not Introduce Water into the System• Forms Sulphuric or Sulphurous Acid• Use 316 SS or Higher Alloy

• (ii) Solids• Where From? - Base Pad Removal• - Spill Clean Up• - Autoclaves• Use Cantilever Shaft Verticals and • Horizontals with Hard Metal Wet Ends

• (iii) Carsul• Found Occasionally in Sulphur• Gummy Globular Carbon Material • Which Hardens When Exposed To Air• Keep Evenly Distributed Sometimes • By a Mixer


• HORIZONTAL MOLTEN SULPHUR PUMPS

• TYPES• ANSI Pumps with jacketed casings, seal housings, and

seal glands• Limited in pressure capability

• Fully Jacketed API 610 Pumps• Very Expensive and Long Delivery

• Other Fully Jacketed Special Designs• Very Expensive and Long Delivery


• HORIZONTAL MOLTEN SULPHUR PUMPS Continued

• The “Achilles Heel” of Horizontal Molten Sulphur Pumps.

• What is it?

THE MECHANICAL SEAL!


• THE SECRET TO LONG MECHANICAL SEAL LIFE• A Different or Better Seal? • A Seal Flush?• A Steam Quench?• A Magdrive?• No, Then What Is The Secret?• Eliminate What?• ------------------------------------------------------------------------------------

• UPSETS• Deadheading• Running Dry• Lack of Temperature Control • Overall or Localized Pressure Surges or Hydraulic

Shock Due to Control Valves, etc.

• THE MOST COMMON UPSET OF ALL

• STARTING AND STOPPING THE PUMP

• Eliminate It if At All Possible!



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