Knowledge for the Sulphuric Acid Industry
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DKL Engineering, Inc.
Storage/Loading/Unloading - Tank Car Loading
April 2, 2008
Safety and Preparation
Tank Car Loading
Locating the Container
Setting Safety Flags
Inspect Shipping Container
Determine the Tank Contents
Termination of Loading
Sealing of Container
The following procedure is applicable to loading of tank cars.
The procedure is general in nature and must be adapted to the specifics of each loading facility and to the owners own procedures and rules.
Attendance by a qualified person during the entire unloading procedure should be required. This person must be thoroughly familiar with the hazards of sulphuric acid and all operating, emergency, safety and first aid procedures recommended for its safe handling.
Water in large quantities should be immediately available at the unloading site to wash down any acid that may be spilled.
A safety shower is recommended along with a signal system designed to get assistance if an emergency should arise. The signal system and safety showers should be tested routinely.
Signs restricting access to the area should be used.
The slow attack of sulphuric acid on mild steel results in the formation of hydrogen sulphide gas which is flammable and can form explosive mixtures with air. Smoking or other sources of ignition should not be permitted near acid tank cars, and cars fittings should never be hammered or chiseled.
The tank car must be accurately spotted at the loading platform so that the loading ramp lines up with the opening on the tank car platform.
Firmly apply the tank car handbrake and block the wheels using standard wheel clamps.
The loading ramp can be lowered into place once the tank car has been spotted and secured.
Blue warning flags and derails should be placed at least 1 1/2 car-lengths away.
Inspect the shipping container for leaks or damage which could interfere with safe loading.
Shipping containers as received will frequently be under pressure either because of thermal expansion of the acid or slow hydrogen generation.
Carefully open the air connection valve if the truck is so equipped and vent any pressure in the container. If there is no air connection, the safety vent should be removed.
If no venting occurs, check to make sure the air connection and valve are unobstructed. Carefully loosen the fill hole cover bolt (do not disengage), and pry up slightly. If any pressure is present, let it bleed off slowly until no pressure is in the tank, then open the fill hole cover.
Caution: All pressure must be vented before any container fittings are removed because of the danger of acid spray. Do not remove the cap from the liquid eduction pipe until it is definitely known that all pressure has been vented from the container, and that the valve is closed (if so equipped).
Check to see if the tank car is completely empty. If the car is not empty, the amount of acid left should be measured. Any acid remaining in the tank car must be accounted for in terms of the amount of acid to be loaded to avoid overfilling the tank car.
Ensure that the loading system is ready to deliver acid to the tank truck. The tank vent should be checked to ensure that it is open. Ensure all valves are properly set for the loading operation.
Place the loading nozzle in hatch and chained the loading line into a secure position.
Inspect the system to be sure and all valves are properly positioned to deliver acid.
Start the loading pump to begin loading acid into the tank car.
Check that acid is flowing into the tank car without approaching the top of the tank car. This can be done by watching for movement of the fill pipe or listening from the bottom of the car for acid flowing into the car. If acid is not flowing into the car, stop the pump. Recheck all the valves and ensure the pump is operating properly.
If leaks develop or acid is spilled, promptly wash down any surface where acid has spilled with an excess of water being extremely careful to avoid getting water into the container, piping or into large accumulations of acid in holes or trenches.
While the car is loading the pump must be shut off before climbing onto the loading platform. This is to minimize hazards to the loader due to overflowing as it is being approached. The pump can be restarted on the platform after it has been determined there is acid required to fill the tank truck.
When the acid reaches the required outage shut off the loading pump and close valve on loading line. Remove the loading line from the fill hole.
If a sample of the acid is required, it should be taken after loading is complete and the loading nozzle removed from the hatch.
Close the fill hole cover tightly and replace the caps on the air connection valve and liquid eduction line. Replace the valve covers. Inspect the container and place proper DOT required placards on the container for the return shipment.
Wash down any acid spills from the top of the tank car and raise the loading platform.
Obtain the necessary bills of lading signed as required and check to see that the safety data sheet and driver instruction sheet are attached.
Check that the truck for signs of leaks and ensure that the placards are in
place. If the truck is not in satisfactory condition or there is a problem
the truck should not be allowed to leave until the problem is corrected .