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Originally published:  01/04/2012
TEMPERATURE CONTROL A number of chemical products present serious safety hazards if they are not kept at the appropriate temperature. Klinge Corp looks at the potential consequences and some ways of controlling the risk
An exothermic reaction can occur when some chemicals – such as organic peroxides and self- reactive substances – are not maintained at the correct temperature. Exothermic reactions involve the release of energy, usually in the form of heat or, possibly intentionally, as electricity or sound.
During transport and storage, there is an obvious hazard from chemicals that are likely to release energy in the form of heat. This may involve a flame, spark or explosion, or a build-up of pressure that can cause failure of the containment.
Vessel operators and masters can be reluctant to accept such products as cargo, due to the risk of explosion. Consignments are often rejected for this reason. However, if properly packaged and stowed, there should be no problem.
The International Maritime Dangerous Goods (IMDG) Code specifies that organic peroxides of Division 5.2 and self-reactive substances of Division 4.1 should be protected against exothermic reaction by being carried in a cargo transport unit fitted with a dual-mechanical refrigeration system. This means: - two refrigeration systems, independent of one another, other than for an integral power supply unit; - each system on its own is capable of providing adequate temperature control; and - for substances with a flash point lower than the sum of the emergency temperature plus 5°C, explosion-proof electrical fittings are used within the coolant compartment to prevent ignition of flammable vapours from the cargo.
In addition, the refrigeration equipment and its controls must be “readily and safely accessible” and all electrical connections must be weatherproof. Continuous temperature measurement inside the coolant compartment is also required. There is no need for two independent integral power supply units, as this is required as a back-up to the power supply from the ship or truck.
Klinge Corporation has been offering dual refrigeration systems with integral power supply to the chemical industry for 30 years. Its ‘Dual Refrigerated Container’ is used by major chemical and pharmaceutical companies such as DuPont, Alzchem, Arkema, and Novo Nordisk for the transport of their goods. It comes in a 20’ or 40’ ISO container size.
The Dual Refrigerated Container contains two (primary and back-up) independent refrigeration units, Model NMR-262. The refrigeration unit automatically switches to its back-up in the case of a loss of performance. Components in the evaporator section are explosion protected in accordance with the EX G3 norm (UL Class 1 Group D).
The Dual Refrigerated Container System also includes an integral generator set, Model NMG- 115, to ensure complete and independent protection of the cargo. The self-powered generator set powers the refrigeration units in case of loss of external power supply or during transport on a truck.
The Dual Refrigerated Container is available with an independent data logger that is linked to an independently powered audible and visual alarm system that sounds in the event that failure occurs. The recorders provide evidence of correct temperatures for every trip in the form of a delivery ticket or numerical or graphical printout. All data is stored with a date/time stamp in a large flash memory. Data will not be lost if power supply is disconnected. The real-time clock is powered by an internal back-up battery.
As an added fail-safe, Klinge Corporation offers satellite communication using Inmarsat. Klinge Corp’s satellite system is a two-way data communications service that uses compact equipment with integrated GPS for data transfer, remote monitoring, tracking and tracing. The satellite communication system transfers cargo temperature, running condition, alarm status, fuel level in running hours remaining, and power source in near real-time. The data is accessible on a website specifically designed for Klinge Corp’s satellite communication system.
Furthermore, all components, except the evaporator coil, are serviceable from the front. Users have easy access to all components in electric box and the door has lift off hinges.