Production of Light Olefins via Fischer-Tropsch Process Using Iron-Based Catalysts: A Review

Abstract

The production of light olefins, as the critical components in chemical industries, is possible via different technologies. The Fischer–Tropsch to olefin (FTO) process aims to convert syngas to light olefins with high selectivity over a proper catalyst, reduce methane formation, and avoid the production of excess CO2. This review describes the production of light olefins through the FTO process using both unsupported and supported iron-based catalysts. The catalytic properties and performances of both the promoted and bimetallic unsupported catalysts are reviewed. The effect of support and its physico-chemical properties on the catalyst activity are also described. The proper catalyst should have high stability to provide long-term performance without reducing the activity and selectivity towards the desired product. The good dispersion of active metals on the surface, proper porosity, optimized metal-support interaction, a high degree of reducibility, and providing a sufficient active phase for the reaction are important parameters affecting the reaction. The selection of the suitable catalyst with enhanced activity and the optimum process conditions can increase the possibility of the FTO reaction for light-olefins production. The production of light olefins via the FTO process over iron-based catalysts is a promising method, as iron is cheap, shows higher resistance to sulfur, and has a higher WGS activity which can be helpful for the feed gas with a low H2/CO ratio, and also has higher selectivity towards light olefins.

Fisher–Tropsch Synthesis for Conversion of Methane into Liquid Hydrocarbons through Gas-to-Liquids (GTL) Process: A Review

“…A wider range of operating temperatures of up to 320-350 °C can be used to produce light products with a chain growth probability of 0.67-0.68 can be achieved by using ironbased catalysts [86,87]. Thus, the selectivity toward methanation is still not that high, even at temperatures of about 340 °C [28].…”

“…Water formation affects the reaction kinetics when the catalyst is iron-based but not when the catalyst is cobalt-based [87,88]. At the exact operating conditions, the increase in the water partial pressure at high conversions will slow the reaction rate causing a lower CO conversion over one run when an iron-based catalyst is used compared to the case where cobalt is used instead.…”

“…In addition, iron catalysts suffer from coke formation at fast rates when used at high temperatures, and replacement of process catalyst is required. Moreover, carbon dioxide and water can oxidize ironbased catalysts, and thus, their activity is affected [77,87].…”

Phosphotungstic acid catalysed bioethylene synthesis under industrially relevant conditions

“…Indirect routes involve methane reforming into syngas 10 , from which ethylene can be obtained either directly by means of the so-called Fischer-Tropsch to olefins (FTO) process 5 , or via methanol or dimethyl ether (DME) through the methanol to olefins (MTO) or the DME to olefins (DTO) processes, respectively 5,10 . These processes occur at temperatures between 300 and 540 °C, depending on the used catalysts [11][12][13] . While some of the methanol-related routes are more mature or even commercially available, as in the case of MTO 14 , coupling of methane technologies need to be further developed in order to be a real alternative to the steam cracking process 10 .…”

“…5,10 These processes occur at temperatures between 300 and 540 °C, depending on the used catalysts. [11][12][13] While some of the methanol-related routes are more mature or even commercially available, as in the case of MTO, 14 coupling of methane technologies need to be further developed in order to be a real alternative to the steam cracking process. 10 An issue to be addressed in the MTO process is the fact that the feedstock for this process is currently coal or natural gas-derived.…”