Direct conversion process from syngas to light olefins - A process design study

The scope in this project is the design of a synthesis gas to light olefins (C2, C3) process including a technical and economical evaluation. The challenges in this project are to find a catalyst for the direct conversion to light olefins and to implement this in a process. New and promising concepts for reaction and separation are evaluated and compared to proven technologies. An iron catalyst with MnO and K2O promoters has been selected to catalyze the reaction towards olefins. The CO conversion is sufficiently large (90.4 mole%), but the selectivity towards C2-C3 olefins is only 49.7 mole%. The process is designed according to the systematic process synthesis techniques. The design of the reactor and the separators have been developed. An inlet of 500 t/h syngas yields 47 t/h ethylene and 51 t/h propylene. This is in total 98 t of desired product per hour. The rest of the inlet stream is converted to H₂O (226 t/h), CO₂ (67 t/h) CH₄ (52 t/h) and 56 C₄ and alifatics. A large amount of reactant is converted into byproducts. An economic evaluation based on market prices for products and raw materials shows a positive result. Further research can make the process more attractive. The carbon efficiency is too low (CO₂ and CH₄ are produced) and should be increased by improving the catalyst. The available catalyst data such as selectivity, conversion and lifetime is limited and should be subject of further research.