When it comes to heat transfer solutions, there are a number of tried-and-true options at a plant manager’s disposal. Steam produced from localized carbon fuel has a long history as the go-to “default mode” at many plants and refineries around the world. But there are changes afoot, as more and more organizations are switching to electric power to heat their processes. What’s driving this switch, and why exactly is electric heat an increasingly popular choice despite its relatively greater upfront cost?
The answer comes down to five key factors:
- Safety
- Precision
- Reliability
- Simplicity
- Ecological impact
You may be surprised to find that ecological impact is not listed first. It’s true that the use of electric heating minimizes emissions at the point of use, but as part of the discussion, the source of that electric power must be considered. Electric process heating is not a panacea, nor is it the end destination; it is a direction to be assessed and modified as needed. Safety must always come first.
1. Safety
One of the drawbacks of steam heating is the frequent use of a hydrocarbon as the source. This may expose the process to the risk of failure and fire, especially if the steam generator is located within the plant and within a classified Area (Division 1 / Zone 0 & 1). For classified hazardous areas, wherein steam is generated, design considerations can be taken to minimize risk—however, these can add cost and require an investment in both time and engineering effort to execute.
Electrification, on the other hand, is a much simpler solution. Critically, no open flame is involved. Explosion-proof certification is designed into the associated components of the heater (and if needed, the associated control panel as well). And, as long as personnel safety measures are implemented, electric heating can easily be installed and operate within hazardous areas.
Typically, certification from authorized bodies such as CSA and ATEX will ensure the electric design keeps the skin temperature of the exposed parts below the LEL or lowest explosive limit of such volatile substances. The result is a tried and tested solution for when process plants must prevent explosion from any free volatiles present in the atmosphere.
2. Precision
Electric heating, controlled by thyristors, allows for degree-specific control over a wide range of temperatures. Because electric power can be increased or decreased by degrees, operations can regulate timing and input of the exact amount of heat required to meet the process duty.
That control means little risk of over- or underheating process fluids, an especially useful attribute for limited-temperature processes. Concern about fouling is further reduced by limit trips for low-flow/no-flow and overtemperature thermocouples where the signals are fed directly and instantly to the DCS and control panel.
3. Reliability
Plants that run make money. Electrification can help make sure you’re up and running. Traditional steam heat requires configuration and integration of many components: from jointed pipes to superheaters and steam traps, with all of the associated condensate recovery piping and systems. These all represent potential leak paths which must be constantly monitored and, frequently, inspected or replaced. By comparison, electric heaters are static and self-regulating, requiring much less monitoring and maintenance.
At Armstrong Chemtec, every electric heater is designed in-house in accordance with both governing pressure vessel codes (ASME VIII Div 1 in the USA – or PED depending on final location), and local safety design requirements (CSA, CSA USA, ATEX, PESO, CCOE etc.). This dedication to safety and quality will help protect your plant from failure and downtime.
All of this combines to offer greater peace of mind for both plant operations and maintenance. Your company can count on a long lifecycle of precision-regulated heat without the ancillary piping and storage of fuel—and without the associated maintenance.
4. Simplicity
Another important benefit of process electric heat is the minimization of required equipment. Steam piping is completely eliminated, along with steam systems, heaters, and additional supporting infrastructure. Quantitatively, electric heaters require a smaller footprint within the plant. That gives room for airflow, access for inspection, or space for the replacement of heating bundles which can reduce turnaround time by weeks. This smaller footprint can be especially useful given the economics of newer plants, as industrial real estate continues to scale in cost.
A streamlined heating system is also easier to monitor and maintain. Operations will be able to effectively keep tabs on a single piece of equipment instead of a piping system, fuel delivery system, and associated supports. Fewer components mean fewer points of failure.
5. Ecology
The fifth most common reason to consider a switch to electric heating is often its most publicized: the benefit of zero on-site emissions. Many nations and municipalities are ramping up efforts to curb carbon emissions as part of a global mission to decrease greenhouse gases. And while the exact regulations vary from location to location, there is seldom, if ever, any resistance to electric process heaters or furnaces.
This may be the most obvious reason to choose electrification at your plant. Fewer emissions are a clearly visible improvement. However, it should be noted that the green effects of electrification can sometimes be overinflated. After all, the energy is still being created somewhere, and it very well still may be by burning fossil fuels.
To switch, or not to switch?
Ultimately, a company’s decision to switch from fired or steam heat to electricity will come down to the specific needs and goals behind its processes. There are costs involved, and switching requires good engineering and no shortage of time and effort. However, an electrically heated process can deliver greater safety, reliability, simplicity, and precision, with fewer on-site emissions. And that’s a pretty powerful combination of benefits.