Powering the Transition to Net Zero with Electric Cracking Technology

This article provides an update on a technology demonstration of an electric cracking furnace and considers future integration options into petrochemical sites.

The petrochemical industry accounts for approximately 5% of global carbon dioxide emissions (1), with steam cracking processes responsible for a significant share of this output. Steam crackers generate as much as 25% of the greenhouse gas (GHG) emissions of the European chemical industry; globally, steam crackers account for hundreds of millions of tons of GHG emissions per year (2–4). In light of this, innovative technologies must be developed and rapidly made accessible in order to achieve carbon neutrality and counteract the negative climate impact of GHG emissions.

More than 90% of today’s CO₂ emissions in modern steam cracking plants are owed to the high energy requirements of this process (3). The endothermic conversion that takes place in the cracking furnaces requires high temperatures — for example, the coil or reaction tube outlet has an operating temperature of roughly 850°C and a maximum tube metal temperature of up to 1,100°C. The additional energy necessary for the separation section, which separates the raw cracked gas into commercial high-value chemicals (HVCs), is also significant.

With the currently established conventional steam cracking technology, the main energy supply for the entire plant is provided by burning the plant’s methane fraction byproduct and natural gas in the cracking furnaces. In addition, the required utility steam is generated from waste heat. A substantial portion of a steam cracker plant’s Scope 1 GHG emissions are released into the atmosphere via the furnace stacks. Therefore, the electrification of cracking furnaces represents an opportune starting point for significantly reducing GHG emissions and achieving the sustainability goals set out in the 2015 Paris Climate Agreement.

The electrification of cracking furnaces differentiates itself from other steam cracker decarbonization methods mainly through its avoidance of CO₂ generation. Other decarbonization methods based on the elimination of the generated CO₂ emissions, such as fluegas CO₂ capture and blue hydrogen firing, all depend on CO₂ capture and the subsequent storage and/or utilization of the captured CO₂. In contrast, electric furnaces operate without any additional expenses for CO₂ capture and handling. They are particularly suited for locations with high availability of renewable or low-carbon power supply and long-term low electric energy costs.

The first part of this article presents the electric cracking furnace technologies that three companies are working in partnership to demonstrate (5). Two alternative electrical heating concepts for steam cracker furnaces have been developed and are currently being evaluated in a large-scale demonstration plant.

The second part of the article highlights the main differences in the heat duties of an electrically heated cracking furnace compared to those of a conventional fired furnace. Said differences may significantly impact a plant’s energy balance but, at the same time, reveal a large potential for increasing the plant’s overall efficiency. Selected heat integration schemes, from the less-complex to the more intricate, enable the adaptation of the eFurnace periphery to project-specific boundary constraints. Special equipment designs for high-temperature heat exchange from reactor effluent to reactor feed are disclosed, and the article provides specific details on the technical design.