|  | Drum Storage
ExxonMobil Chemical uses unlined mild carbon steel drums equipped with 3/4" and 2" bungs and are in accordance with DOT specification 17E. Jayflex plasticizers are thermally stable. However, exposure over long periods of time to excessive temperatures, such as encountered in drums stored in direct sunlight in hot weather, will tend to degrade product quality, particularly color and odor, and is not recommended.
ExxonMobil Chemical Jayflex plasticizers are a Class IIIB combustible liquid with a flash point exceeding 200°F (93°C). A combustible liquid is defined as having a closed cup flash point at or above 100°F (38.7°C).
There are no universal standards for storing material, but the National Fire Protection Act (NFPA) is the fire code adopted in most states. Check local fire codes to determine the best way to store material in your warehouse.
Tank Storage
Tank storage is an economical alternative for large users of Jayflex plasticizers. Bulk shipments, ease of handling, better inventory control and reduced labor requirements all represent savings that can offset the cost of tank installation.
Size
Minimum size should be 6,000 gallons and preferably 10,000 gallons. The storage tank should be large enough to hold the minimum working inventory plus the volume of incoming shipments. When sizing tanks, consider future requirements and lead times for deliveries.
Materials of construction
Mild carbon steel is satisfactory for storing Jayflex plasticizers. Rust-Ban® 191 or a similar coating will reduce rust formation. Aluminum or stainless steel may be used but are generally not necessary. Construction requirements for tanks are based on National Standard API-650 "Tankage for Petroleum Liquids."
Tank construction
Consider these design features.
- A sloping bottom or a sump in the tank for cleaning, sedimentation and water draw-off purposes.
- Adequate manways for tank cleaning and inspections.
- A level gauge to indicate inventory level in the tank.
- If heating is required, a thermowell in the side of the tank for a thermometer or temperature controller and two connections for steam inlet and condensate outlet piping form an internal heater (optional).
- A tank vent (open gooseneck or pressure-vacuum type). Vent size depends on the tank capacity and maximum filling and transfer rates. Also consider an inert gas blanketing system to minimize moisture pickup and other contamination.
- Underground and elevated horizontal tanks on piers. Consider proper anchoring, corrosion protection, fireproofing of piers, etc. Consider tank location, need for firebanks, toe walls, etc. to assure approval from appropriate regulatory agencies.
Heating
In cold climates, heating of viscous plasticizers may be necessary. This is done by using internal coils, an external pump-around heater or circumferential plate coils affixed to the tank exterior. Circulating hot fluid, such as water below 200°F, is preferred to heating by steam in order to minimize risk of product degradation. However, low pressure steam can be the heating source if used in combination with internal circulation or pump-around to prevent localized hot spots and the potential for product degradation. Tank temperatures should be kept as low as possible consistent with desired pumping rates. Inspection procedures should ensure that the internal heating coils do not leak and cause water contamination. Periodic pressure testing is one way to accomplish this.
Lines, pumps, valves, etc
Carbon steel is satisfactory for lines, pumps and valves. Centrifugal pumps or positive displacement pumps may be used for product transfer. Mechanical pump seals are required, consistent with environmental regulations. Check valves should be used on pump discharges to avoid contamination by back flow through the pump. Flexible lines of neoprene, butyl, EPDM or polysul- fide rubber make satisfactory connections from the car or truck to the storage tank line. Garloc® or graphite gaskets are satisfactory for flanged connections. Teflon® tape should be used on all threaded pipe joints.
Startup of new facilities
New facilities should be cleaned and dried before being placed in operation. All scale and other foreign matter should be removed. Before use, the tank and lines should be conditioned with product to remove scale and dirt.
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