The capacity of that line is approximately 284 barrels or 0.11% of the total cargo. A chemical vessel discharges a 3,650-barrel (500 metric tons) parcel through a shore line that is 6" in diameter and 1,000 feet long. The capacity of this line, while only 35 barrels is 0.96% of the total cargo. Also, the price of a chemical cargo is typically ten times the price of crude oil. Therefore, losses due to slack shore lines, gauging or temperature errors, etc., usually have a greater impact on small chemical parcels than on a large petroleum shipment. Calculations With petroleum cargoes we typically use a volume correction factors from ASTM D 1250 (API Chapter 11.1) to convert observed volumes to volumes at standard temperature and then using a density at the same standard temperature to convert the volume to mass. However, there are numerous calculation methods used for determining chemical quantities. While the use of volume correction factors is used in the determination of chemical quantities it is less common than other methods. Each chemical has its own thermodynamic properties and therefore needs its own volume correction factor. The more common method is to apply a density to a volume to arrive at mass (weight). However, this has a number of variations. You may have a table that gives each density over a range of temperatures.
Generally, the volume correction factors for petroleum products per ASTM D 1250 (Table 6A, 6B, etc.) are not applicable for most chemicals because chemicals were not used in determining these volume correction values. However, these tables may be used on agreement of all the commercial parties involved. 6.7 Safety Although safety is always the number one priority with any type of inspection, chemicals usually represent a greater level of hazard than petroleum products. 6.7.1 Safety Data Sheets The safety data sheet for each chemical being handled should be reviewed prior to leaving the office to go to the job site. Personal protective equipment, especially respiratory protection, must be checked to ensure that it will provide the required level of protection in addition to being clean and in good working order.
6.6 Cargo Pipelines The shore line condition can be critical to both quantity and quality of the cargo. The inspector must be very vigilant in situations where dedicated shore lines are not available. In these situations, the shore line is usually displaced by pigging or blowing air or nitrogen back to the tanks. Pigging generally produces a better result, although caution must be exercised regardless of the method. Always obtain a start-up line sample in these situations. The ship’s lines are also possible sources of contamination, either from previous cargoes that were not removed or from water residues from the cleaning operation. Where possible, the vessel’s lines should be blown from the manifold back to each tank that is going to receive cargo. The quantity of the shore line usually has a greater impact on chemical cargoes than on petroleum products, which are typically shipped in large parcels whereas chemicals are usually shipped in small ones. This lends to higher percentage quantity losses when dealing with chemicals. Slack Shore Line For example: A petroleum tanker discharges 250,000 barrels through a 12" shore line which is 2,000 ft. Long.
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