Cylinders with contaminated contents

The use of water-contaminated oil causes an increase in piston ring wear by a factor of two. The deposition rate of carbonaceous matter on the cylinder-piston group parts is increased by a factor of 2-3 when water contaminated oil is used as compared to uncontaminated oils (Kozhekin et al., 1978 Shishigin and Belganovich, 1976 Somov et al., 1978). After 100 hrs of shipboard engine operation at 80% rated power with water contaminated oil, its TBN value dropped by 58%, whereas that value only dropped 22% for the dry oil. Similarly, the benzene insoluble contaminant content was 2.8% and 0.7%, respectively. 

In the absence of air, TEE disproportionates violently to give carbon and carbon tetrafluoride the same amount of energy is generated as in black powder explosions. This type of decomposition is initiated thermally and equipment hot spots must be avoided. The flammability limits of TEE are 14—43% it bums when mixed with air and forms explosive mixtures with air and oxygen. It can be stored in steel cylinders under controlled conditions inhibited with a suitable stabilizer. The oxygen content of the vapor phase should not exceed 10 ppm. Although TEE is nontoxic, it may be contaminated by highly toxic fluorocarbon compounds. 

A cylinder should never be emptied to a pressure lower than 172 kPa (25 psi) because the residual contents may become contaminated with air if the valve is left open. Empty cylinders should never be refilled by the user. Rather, the regulator should be removed, and the valve cap should be replaced. The cylinder should be clearly marked as empty (MT) and returned to a storage area for pickup by the suppUo-. Empty and full cylinders should not be stored in the same place. 

Cylinder valves are now often equipped with enhancements that are becoming increasingly popular such as residual check valves that retain a positive pressure in a depleted cylinder to prevent cylinder contamination. This also allows the end user to withdraw contents from the cylinder while preventing the user from recharging the cylinder. Flow restrictors are in-... 

If the contents of a cylinder have been contaminated or are suspected of being contaminated, analysis of the contents should be conducted prior to establishing the handling procedures and disposition. Mixtures containing components that are incompatible with one another or their container are prohibited from being shipped under DOT (see 40 CFR 173.301) and TC regulations [1,2]. Only specially trained and experienced personnel should handle potentially reactive or explosive mixtures. 

Some cylinders have contents that change their chemical characteristic over time (decompose, polymerize, etc.). Examples include 1,3-butadiene, hydrogen bromide and diborane. These changes may eventually result in overpressurization that exceeds the specification of the cylinder. This situation renders the cylinder unsafe for transport. Contents of cylinders that have become contaminated with foreign material may also result in a chemical reaction causing overpressurization or an explosive hazard. These cylinders should be handled with extreme care and only by specially trained and qualified personnel. 

In another incident, a cylinder of silane detonated while two personnel of an analytical company were analyzing the contents of a cylinder. In this incident, it is surmised that a semiconductor manufacturer inadvertently cross-contaminated the silane with an oxidizer. The silane was originally used by semiconductor company (A) where the contamination probably... 

A cylinder should be considered empty when its internal cylinder pressure reaches 25 p.s.i.g., unless the cylinder contains a gas having an extremely low vapor pressure. Withdrawal of the entire cylinder contents should be avoided as this may allow entry of moisture or contaminants that can result in delivery of impure gases when the tank is next refilled, or more seriously, in damage to the tank itself. For example, carbon monoxide contaminated with water vapor under pressure can cause stress-corrosion of the cylinder. 

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