38 | Plant & Works Engineering www.pwemag.co.uk April/May 2023 Energy & Environmental Management Focus on: Boilers, Burners & Controls Decarbonising petrochemical refining Petrochemical processes have traditionally been heated with fossil fuels, but pressure is building to mitigate carbon dioxide emissions and advance long-term decarbonisation goals. Fossil fuel heated processes leave big shoes to fill when it comes to thermal processes, so electric process heaters often raise two big questions: how big can an electric heater be? And what is required to maintain proper control of large electric heaters? Dennis Long, chief system designer at industrial electric equipment manufacturer Watlow, explains further. The technology behind process heaters has changed dramatically in the last ten years. This is good news for the industry, as electric heaters must be able to provide the same or improved performance that petrochemical engineers have come to expect from fossil fuel powered heaters. Electric process heaters Vs fossil fuel burning heaters To even consider replacing fossil fuelburning heaters, we need to have a clear understanding of the current capabilities of electric process heaters. For instance, replacement does not make sense if electric heaters don’t come with the size and power required to heat processes that currently depend on fossil fuels. Many of those processes would require larger electric heaters well above the common one-megawatt (MW) variety such as fluid catalytic cracking (FCC) heaters that require between 150 to 200 MW of power. With equipment of this size, a single vessel can have two heat exchanger bundles. Such a setup can produce a single process vessel with a 15 MW duty rating or more. The few suppliers providing electric heaters at this scale can raise or lower the duty rating as technical requirements dictate. This kind of size and power presents a viable alternative for operations currently fired by fossil fuels. Besides reducing the use of fossil fuels, electric heaters and heat exchangers have other well-documented advantages including less thermal lag, safer operation due to no fossil
RkJQdWJsaXNoZXIy MjQ0NzM=