number of key advantages for the various temperature
maintenance and freeze protection applications.
Several key criteria are considered when selecting the type
and configuration of heating cable including performance,
power consumption, environmental and hazardous area
requirements, installation and maintenance characteristics and
control system integration. The heating cables must be suited
for the environment and designed for a long service life,
minimising costs associated with potential replacement and
down times.
In the example provided, an eltherm industrial design ELSR
self regulating heating cable was chosen for the foundation
heating circuits and the ring wall heater assembly.
Control
While the heat tracing portion of the overall system can be
considered the heart, it is the monitoring and control system
of the LNG tank base that provides the brains of the operation.
Without a properly functioning control system, a tank base
heating design simply cannot function. Since the heating
system must be capable of operating at all times, redundancy
must be built in to ensure that if any part of the system fails or
shuts down, the back up is capable of picking up the slack until
the primary mode of operation can be repaired and restored.
Figure 3 provides an example of an eltherm designed LNG
tank base heating system with complete redundancy.
Temperature sensors are strategically placed within the centre
of the heated zone and along the wall heater. In this
installation, the control system is designed so that a load
change can occur automatically between the main and
redundant system. In case of any failure of the operating or
primary system, the control system is programmed to
Figure 4.
LNG tank foundation heating scheme.
Figure 5.
Basic system architecture, eltherm LNG
tank base heating system.
Cryogenic Components
Visual Level Indicators
Stainless Steel Valves
Tank Level Instruments
WEKA AG · Switzerland
Schürlistrasse 8 · CH-8344 Bäretswil
Phone +41 43 833 43 43
Fax +41 43 833 43 49
·
ARCA Flow Group worldwide:
Competence in valves, pumps & cryogenics
