Selective CO Hydrogenation Over Bimetallic Co-Fe Catalysts for the Production of Light Paraffin Hydrocarbons (C2–C4): Effect of Space Velocity, Reaction Pressure and Temperature

Seong Bin Jo,Joon Woo Kim,Soo Chool Lee,Tae Young Kim,Chul Ho Lee,Suk-Hwan Kang,Ho Jin Chae,Jae Chang Kim,Jin Hyeok Woo

doi:10.3390/catal9090779

Abstract

Synthetic natural gas (SNG) using syngas from coal and biomass has attracted much attention as a potential substitute for fossil fuels because of environmental advantages. However, heating value of SNG is below the standard heating value for power generation (especially in South Korea and Japan). In this study, bimetallic Co-Fe catalyst was developed for the production of light paraffin hydrocarbons (C2–C4 as well as CH4) for usage as mixing gases to improve the heating value of SNG. The catalytic performance was monitored by varying space velocity, reaction pressure and temperature. The CO conversion increases with decrease in space velocities, and with an increase in reaction pressure and temperature. CH4 yield increases and C2+ yield decreases with increasing reaction temperature at all reaction pressure and space velocities. In addition, improved CH4 yield at higher reaction pressure (20 bar) implies that higher reaction pressure is a favorable condition for secondary CO2 methanation reaction. The bimetallic Co-Fe catalyst showed the best results with 99.7% CO conversion, 36.1% C2–C4 yield and 0.90 paraffin ratio at H2/CO of 3.0, space velocity of 4000 mL/g/h, reaction pressure of 20 bar, and temperature of 350 °C.

Highlights

At present, the production of synthetic natural gas (SNG), mainly consisting of methane, has aroused extensive attention and been commercially produced from different starting materials, including coal and solid dry biomass [1,2,3,4,5]
Few studies have made an effort to produce mixing gases consisting of paraffinic C2 –C4 hydrocarbons into Synthetic natural gas (SNG) for power generation
Bimetallic Co-Fe catalysts supported on γ-alumina were developed, and the effects of operating parameters such as space velocity, reaction pressure and temperature on catalytic performance were elucidated for the production of light paraffin hydrocarbon yield (C2 –C4 range) with high paraffin ratio, as well as reduction of byproduct formation (C5+ and CO2 )

Summary

Introduction

The production of synthetic natural gas (SNG), mainly consisting of methane, has aroused extensive attention and been commercially produced from different starting materials, including coal and solid dry biomass (e.g., wood and straw) [1,2,3,4,5]. For power generation, liquefied petroleum gas (LPG, C3 –C4 hydrocarbons) must be added to SNG to enhance its heating value; the price of LPG is strongly correlated with that of oil. Catalysts 2019, 9, 779 synthetic light hydrocarbons (C1 –C4 ranges) via Fischer–Tropsch (FT) reaction could be added to SNG as a substitute for LPG by using the same syngas source (H2 /CO ratio = 3.0) for the SNG process. The gas products must maintain a high paraffin ratio, because olefins exhibit a low heating value, as well as being more susceptible to hydration with CH4 and liquefaction than paraffins of the same carbon chain length under pipeline conditions (-5 ◦ C, 70 bar) [13]. The FT product gas must have a high paraffin ratio in C2 –C4 ranges, as well as a high light hydrocarbon yield

Methods

Results

Conclusion