Unloading Tank Cars

Chemicals Chemical Manufacturers Association 2501 M Street, NW Washington, D.C. 20037 Manual of Standard and Recommended Practice ios. chemicals, containers, tank car unloading, and related procedures. 

Bulk unloading facilities usually must be provided at the treatment plant. Rail cars are constructed for top unloading and therefore require an air supply system and flexible connectors to pneumatically displace the alum from the car. U.S. Department of Transportation regulations concerning chemical tank car unloading should be observed. Tank truck unloading is usually accomplished by gravity or by a truck mounted pump. 

Figure 4-2 A typical tank car unloading system for unloading compounds with low boiling points. Courtesy Dow Chemical Company, U.S.A. 

Tank Car Unloading Safety Checklist Return Procedures Bulletin NPGA... 

Fuel Oil Unloading No. 6 fuel oil. Tank car unloading area and containment trench for piping... 

Who Train employees responsible for tank car unloading operations... 

A vented cylindrical tank is used for stor tank car unloading facility and a continue uses the tank car contents as feedstock (Fig tor feed exits the storage tank at a constant i m /s. During some periods of operation, fee taneously transferred from the tank car to and from the tank to the reactor. The operat particularly careful not to let the feed tank overflow or empty. The feed tank is 5 m high (distance to the vent) and has an internal cross-sectional area of 4 m. ... 

Consider the tank car unloading of a hazardous chemical, as shown in Fig. 5.6. A pump is used to empty the tank car and fill the storage tank. Then the chemical is transferred to a chemical reactor. Describe the discrete steps necessary to carry out such an operation and discuss any safety issues associated with the transfer of the hazardous chemical that is, what instrumentation and alarms would you recommend installing ... 

Who Train employees responsible for tank car unloading operations When Initially, or prior to assignment What records Specific training documentation is not required... 

Handling Temperatures. Optimum temperature for pumping is in 37—48°C range. Piping should be stainless steel, aluminum, or galvanized iron. Valves and pumps should be bronze, cast-iron with bronze trim, or stainless steel. A pump of 3.15-L/s (50-gal/min) capacity unloads a tank car of warm glycerol in ca 4 h. 

When loading or unloading a tank tmck or tank car, static bonding lines must be attached between the vehicle and the fixed piping system. Tank tmck drivers may be inexperienced in the handling of chemicals and, therefore, it is essential that the plant personnel be alert in checking the driver s operations and in correcting any possible deficiencies (see Transportation). 

Shipment and Storage, Specifications. A/-Vinyl-2-pyrrohdinone is available in tank cars and tank trailers and in dmms of various sizes. Shipping containers are normally steel or stainless steel. Tank cars are provided with heating coils to facihtate unloading in cold weather. Rubber, epoxy, and epoxy—phenohc coatings are attacked and must be avoided. Carbon steel has been successfully used for storage tanks, but stainless steel preserves product quahty better. Aluminum and certain phenohc coatings are also satisfactory. 

Unloading Flammable Liquids from Tank Cars, Manual Sheet TC-4, Manufactuting Chemists Association, Washiagton, D.C., 1969. 

When classifying extent of space, consideration shall be given to fact that tank cars or tank vehicles may be spotted at varying points. Therefore, the extremities of the loading or unloading positions shall be used. 

Loading and unloading of tank cars and tank trucks represent an increased potential for spill or release. Design and operation must be conducted to minimize the chance for spill, release, or fire and to ensure protection of personnel and facilities. 

For flammable liquids, top loading or unloading of tank cars or tank trucks by pump typically has the lowest risk of spill or release. Metallic piping is recommended for loading/unloading arms and piping. Use of hose should be minimized and, where possible, metallic hose specified. Standard loading racks should be provided that permit safe access by personnel to the rack itself and onto the tops of the cars or trucks. Fall protection is a key issue. 

Where unloading of flammable liquids must be done from the bottom of the tank car or tank truck, a remote actuated unloading valve equipped with a fusible link for detecting high temperature should be provided. 

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