Sustainable innovations in steam cracking: CO2 neutral olefin production
Steam cracking of hydrocarbons is and will continue to be the main industrial process to produce light olefins in the coming decades. In state of the art steam cracking plants more than 90% of the CO2 emissions can be directly related to the high energy consumption of the endothermic conversion in the cracking furnaces. Steam cracking accounts for a global emission of more than to 300 million tonnes of CO2 per annum. Enhancing heat transfer in the radiation section, using green energy and reducing coke formation are key to substantially reduce CO2 emissions. Heat transfer can be increased by implementing three-dimensional (3D) coil technologies such as swirled and dimpled tubes. These reactor technologies also reduces coke formation because of the lower wall temperatures that are consequently obtained. Advanced manufacturing techniques and better computational abilities have opened the door to novel and improved 3D reactor technologies that are designed to increase the heat transfer while minimizing the pressure drop penalty. At the same time applying high emissivity coatings on the furnace refractory and reactor tubes can further reduce CO2 emissions. Substantial fuel savings can also be obtained by a novel furnace design, where the heat recovery scheme is substantially modified. Combining all these technologies could result in reducing emissions by 30%. Shifting completely to green electricity, which is practically infeasible today, is another alternative but the technologies that would potentially allow this are still in their infancy. These new technologies, combined with advanced process innovations and CO2 capture, will help the industry to meet future emissions targets.