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systems are replacing fuel fired heating systems. Electric
heating systems also provide added benefits when
compared to fired heating systems, including: reduced
footprint, lower installation and maintenance costs,
reduced downtime, and extremely accurate temperature
control.
In the past, the biggest restriction to considering
electric process heaters was the large amperage
requirements when using low voltage (up to 690 V)
for the power supply to the heating systems. With the
advancement of Chromalox’s DirectConnect™ technology,
large process heaters can now be operated on medium
voltage (up to 7200 V) and reduce amperage and wiring
size requirements by a factor of at least nine times.
Electric heating systems have reduced footprint due to
the ability to directly heat the process fluid. By
comparison, most fired heaters indirectly heat the process
fluid. The direct heating capability of electric heaters
allows for a more compact footprint to deliver the same
heat energy as a similar sized fossil fuel fired heating
system. Electric process heaters also have design
flexibility and can be installed in either horizontal or
vertical orientations.
Lowers installation cost
When comparing the installation costs between electric
and fired heating systems, the entire installation
and process associated with the project needs to be
considered. As noted above, fuel fired heating systems
typically indirectly heat the process medium, which
requires additional equipment, such as a heat exchanger
and the required piping to and from the fuel fired heat
source. The additional equipment and piping not only
adds cost to the project, but also the time to design
and install piping, which may require high temperature
and pressure valves and piping. With electric process
heating systems, the piping runs to and from the process
are limited since electric heaters can easily be placed
outdoors and in Class 1, Division 1&2 electrical hazardous
rated areas. The ease of installation and closer proximity
to the processing area drastically reduces installation time
and costs, while increasing overall safety at the facility.
Maintenance for an electric heating system is almost
negligible when compared to fossil fuel fired heating
systems. Electric heating systems include a flanged
immersion heater, which has many individual resistance
heater elements attached to the flange tube sheet. The
flanged heater bundle is then installed into a
pressure vessel or storage tank. There are no
moving parts, tuning of the fuel train, blowers
and soot clean out required with an electric
heater bundle. Regular checks on the electrical
connections is all that is required. The heater
control panel can feature many diagnostics and
communications to confirm the operational
health of the electric heating system. Electric
heating systems also do not require a dedicated
operator since electric heating systems are
considered an unfired vessel and do not need
the same operator and inspector investments.
Fast maintenance
turnaround
Downtime is one of the most costly issues which
affects LNG and other gas processing facilities.
Electric heating systems have no moving
parts and do not burn fuel to generate heat,
Table 1.
480 V construction
Product
Process heaters
US$1 917 000
Power control panels
US$1 692 000
Startup service
US$78 000
Sub-total
US$3 686 000
Installation
Transformer
US$1 196 000
250 ft run to panel
US$1 686 000
500 ft run to heater
US$3 371 000
140 labour hours
US$63 000
Sub total
US$6 316 000
US$10 001 000
Table 2.
4160 V construction
Product
Process heaters
US$3 728 000
Power control panels
US$1 355 000
Startup service
US$78 000
Sub total
US$5 160 000
Installation
Transformer
-
250 ft run to panel
US$183 000
500 ft run to heater
US$438 000
50 labour hours
US$34 000
Sub total
US$655 000
US$5 815 000
Figure 2.
Chromalox DirectConnect™ medium voltage electric systems.