INCREASING EFFICIENCY IN THE LNG REGASIFICATION PROCESS WITH DOUBLE TUBE SAFETY HEAT EXCHANGERS

Efficient solutions for regasification are in demand and not only at LNG terminals where natural gas is fed into the pipeline network, but also has been increasingly used as fuel on ships. Before combustion, LNG must be transformed into its gaseous state, therefore pre-warming is effective toward enabling more efficient combustion. If, as a result of passive regasification, the fuel is already available as gas, it is required only to place it at suitable pressure and optimal temperature before injecting it into the combustion chamber. Today, shell and tube, plate and printed circuit heat exchangers are primarily used in regasification systems for ships. These systems require an intermediate circuit to separate the media (e.g. hot water, water glycol, steam. propane or natural gas), as well as expensive safety facilities to reliably detect leaks and to prevent gas emission. The purpose of this paper is to present alternatives to the conventional technologies using double-walled safety heat exchangers (DTSHX) which do not require separation by an intermediate circuit leading to savings in the design. DTSHX counts with a leak sensor, installed in the leakage chamber which activates an alarm in the control system in the case of a leakage of steam, water glycol or CNG. Also thanks to the double walls, a leak does not impair the function of the heat exchanger, which ensures extremely high level of system availability. Adaptation of these heat exchangers offer great potential savings and enables the construction of compact and even more efficient regasification systems. These systems require no more space, operate with less energy and are more cost-effective even for initial investment owing to their simplicity.