This procedure is general in nature and as such should be adapted to the specific conditions and procedures existing at the site at the time the operation is performed.

Safety

Hard hat, safety glasses, safety shoes, long sleeve coveralls and gloves.   Supplied air breathing full face mask must be worn at all times while on the tank car dome platform.  Safety belt and lifeline secured to a fixed point to limit any fall to 1.5 M must be worn at all times whilst on the tank car or platform.  Lifeline securing ring on safety belt must be positioned in centre of back.  A similar person similarly attired and equipped must be in attendance at all times.

Equipment and Supplies

The following equipment will be required:

• Non-sparking tools

Procedure

Tank Car Positioning and Preparation

1.             Make sure the tank car has been "spotted" in the correct position so that all connections can be easily made.

2.             Set tank car handbrake and position wheel chocks.  Position derails to north and south of car.

3.             Attach grounding cable to the frame of the tank car being sure that the opposite end is properly attached to ground.

4.             Lower platform to the tank car dome platform and secure it.

5.             Whilst on the tank car dome platform, the air breathing full face mask equipment must be worn and a second operator, similarly attired must be present on the platforms.  Check breathing air cylinders for adequate air supply and open valve to supply air to breathing mask connectors.

6.             As an added precaution, non-sparking tools should be used when working on the top of a sulphur tank car.  Being extremely careful, loosen holddown bolts on dome cover.  The rail car may be pressurized so leave two bolts opposite the hinge till last so the lid won't suddenly spring open.  Loosen these last two bolts and carefully crack open the dome cover with a non-sparking tool.  There may be a dome of solidified sulphur under the cover.  If this is the case, maintain a safe position and puncture the sulphur dome with the non­sparking tool until you can see the sulphur below (This may also be frozen).  Be aware at all times that the car may be under pressure and toxic and explosive mixtures of H2S/Air may be present.  The dome cover should be lowered to the support of two bolts to keep the cover cracked open.

7.             At ground level attach fittings and steam and condensate flexible hoses to the tank car heating coil.   Open steam supply to the car slowly and check that the trap assembly is working correctly and discharging condensate to sewer.  The trap assembly should be checked regularly to see it is functioning properly.

8.             The tank car should be inspected regularly - taking all necessary precautions as listed above - to determine the nature of the sulphur.  This inspection can be carried out by inserting a dip rod into the dome to determine the status of the contents. (N.B. Check steam supply pressure).

Tank Car Unloading

Tank cars will be bottom unloaded with air assist.

1.             Two operators fully equipped as described above are required.

2.             Connect the flexible steam jacketted sulphur line to the outlet on the tank car using the adapter.   Make sure that no solidified sulphur is blocking the outlet of the globe valve on the car - if so, clear with hot stick, etc.

3.             Check the air inlet on tank car to make sure it is not plugged with sulphur.  If it is, use a live steam lance or hot stick to clear it.  If this is done, then the dome must be cracked so the steam is relieved into the car and the operators will be able to see when line is clear.  During this period, extreme caution should be taken because the danger of a sulphur or live steam burn is possible.

4.             Check air line is clear and if so, attach the air valving assembly and air supply hose to the tank car air nozzle.  Insert gasket on dome cover and secure making sure no sulphur has dropped on the gasket.  This would give a poor seal.

5.             Before unloading begins, make sure the tank or pit is ready to receive sulphur.  Verify that the tank or pit level gauge and steam heaters working properly.  Check that steam is on the steam jacketted line and steam traps are functioning properly.  The steam should have been on the jackets for several hours prior to the offloading beginning to bring all the metal up to steam temperature.  Where possible, test flange jumpers and steam traps by "chalking" them with a piece of solid sulphur, if the sulphur melts immediately, then that section should be hot enough to receive sulphur.  The vent from the tank should be clear - make sure the steam tracing on this vent is operating correctly.

6.             Slowly open the valve supplying 30 psig air to the tank car.  Two operators, fully equipped, should be present to check for air leaks at the dome cover and air fittings.  If there is a leak of air at the top or sulphur at the bottom, shut off the air and depressurize the car and attend to the leaks.  Restart the air and recheck for leaks.

7.             Open the plug valve on the tank car slowly, checking for leaks, and when fully open, open the plug valve on the sulphur line slowly.  Sulphur should begin flowing into the tank or pit.   The level indicator should soon begin indicating an increasing level in the tank or pit.

8.             As the tank car nears empty, there will be a point when all the sulphur has left the car and the line empties of sulphur, when the air reaches the pump tank it will blow through the seal pipe and vent to atmosphere.  Shutoff the air supply to the tank car and allow the tank car to fully depressurize.

9.            Close the sulphur valves, disconnect the air supply, steam and the sulphur unloading line. Seal the tank car and prepare to bring in the next tank car for unloading.