Review of Electric Cracking of Hydrocarbons

The cracking of hydrocarbons is a highly energy-intensive process with large CO2 emissions. Industrial steam crackers use gas-fired furnaces, which produce a global CO2 emission of about 366 Mt/year. Modern crackers have been improved through the years to increase performance and reduce greenhouse emissions. However, the improvements are limited, and the required future CO2 emission reductions cannot be achieved with the present designs. Electrification is a promising option to make cracking processes more sustainable, especially if renewable electricity is used. Electric heating will result in energy savings as flue gas losses are avoided, while CO2 emissions will be reduced radically if renewable electricity is used. This paper evaluates the current state of electric cracking and identifies potential electric heating technologies for the electrification of cracking processes. Various electric heating technologies are reviewed, an extensive literature search is conducted on their application in cracking processes, and industrial applications of electric cracking are compiled. The study shows that resistance (Ohmic) heating is a promising electric heating technology for steam cracking of naphtha. The technology is relatively easy to scale up and can be used to retrofit existing crackers. The cost of electric cracking is expected to be higher than conventional cracking, mainly due to the current electricity price being higher than the gas price. However, the cost of naphtha represents about 80% of the ethylene production cost, so possible selectivity improvements could reduce the overall cost through lower feedstock consumption. The electrification of the cracking processes can be stimulated by guaranteeing sufficient availability of renewable electricity and by introducing a CO2 tax.