25,000
22,500
Natural gas Natural gas trend
Propane Propane trend
Fuel oil Fuel oil trend
20,000
17,500
15,000
12,500
10,000
7500 500 250
0
0
2.5
5 7.5 10 12.5 15 17.5 20 22.5 25 27.5 30 32.5 35
37.5
Burner size (MMBTU)
Figure 1 Carbon emissions relative to fuel type
generated using API 560 fossil fuel-fired heaters. API 560 heaters make up the majority of a refinery and petrochemical facility’s CO₂ emissions out of the heater stack. For example, a 34 MMBTU/hr fired heater can emit up to 15,900 tons/year of CO₂. This is equivalent to emissions of 3,245 cars on the road per year. To improve the efficiency of the API 560 heater, heat from the stack is often captured and recirculated to the combustion section of the system to improve the efficiency of the fossil fuel-fired heater. However, the aforementioned drawbacks of WHR are still present, and the emissions are still significant. There are numerous process technologies and refinery/petrochemical designs throughout the industry that are currently serviced by API 560 fossil fuel-fired heaters that are good candidates for electrification using electric resistance technology. A closer look at these processes can reveal how electric heating technology can displace conventional combustion heat sources. For separation units, the most common found in refineries are atmospheric and vacuum distillation. Atmospheric distillation for crude and bio-crude begins with feedstock oils comprised of a mixture of hydrocarbons. This feedstock oil is first heated and then put into a distillation column, also known as a still, where different products boil off and are recovered at different temperatures. The distillation process
separates this crude oil into broad categories of its component hydrocarbons, or ‘fractions’. The temperatures required for the process can extend upwards of 1000ºF, well within the ranges for electric process heaters. After the oil is separated within the atmospheric distillation unit, the heavier residual gas oils are sent to a vacuum distillation unit for further processing and separation. Here the oil needs to be preheated prior to entering the vacuum distillation unit to achieve further separation. This process is endothermic and thus additional heat is often required to supplement the process, another candidate for electric resistance technology. After separation, conversion units take individual hydrocarbon streams and convert them to lighter products by changing their size and chemical structure. An example of a conversion unit is the isomerisation and reformer process. In the reformer unit, naphtha is converted to make high-octane blend components for gasoline. The most widely used conversion method is called cracking, where heat, pressure, catalysts, and sometimes hydrogen are used to crack hydrocarbon molecules into lighter ones, typically gasoline, kerosene, and diesel. Electric heaters have been used in the isomerisation and reformer process for many decades, primarily due to an electric heater’s ability to achieve optimal catalyst bed reactor
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