INDICATIONS that methyl chloride is the rogue refrigerant responsible for three deaths and the grounding of hundreds of reefer containers coincides with a recent warning about fake refrigerants by compressor manufacturer GEA Bock.
While investigators looking into the recent reefer incidents have yet to reveal all the constituents of the rogue blend used in the R134a refrigeration systems, they have confirmed the likely involvement of methyl chloride, an extremely flammable toxic compound used in the early days of refrigeration before the advent of CFCs.
Now methyl chloride, or chloromethane (R40), has been named by German compressor manufacturer GEA Bock as a constituent in fake refrigerants responsible for an increasing number of compressor breakdowns.
While it is unknown whether the incidents are linked, GEA Bock has pinpointed bogus refrigerants purporting to be R134a, which they have found to consist mainly of R22, R30, R40 (methyl chloride) and R142b.
R22 and R142b are both restricted under the Montreal Protocol and R30 (dichloromethane, methylene chloride), like R40, is also highly volatile. But it is methyl chloride which seems to be causing most of the damage.
The Bock warning pinpoints methyl chloride's aggressive nature, dissolving the aluminium body of the compressor and producing "highly inflammable gases which are self-igniting and explosive on contact with air". It also attacks plastics and damages compressor hoses, warns Bock. Even the oil doesn't escape the effects: synthetic POE oil is emulsified by the reaction with methyl chloride and splits into its component materials.
GEA Bock also warns of a another refrigerant posing as R134a but found to be a cocktail of R134a, R22 and, sometimes, propane. This bogus gas is said to cause problems in hot countries by confusing the temperature/pressure characteristics and reducing the pressure so that, when at standstill, the correct refrigerant fill amount cannot be specified. Likewise, the apparent suction gas superheat of 7K is not real, but the compressor runs completely liquid. The addition of R22 means the oil is no longer transported back to the compressor. GEA Bock also warns that the addition of propane increases the fire risk.
ACR News - November 7, 2011