(91e) Process Modeling, Techno-Economic Analysis and Life-Cycle Assessment of Intensified Biogas to Liquid (IBGTL) Process.

Landfill gas (LFG) is a natural byproduct of the decomposition of organic waste in landfills, consisting primarily of methane and carbon dioxide [1]. Despite its potential as a source of renewable energy, the low value of end products such as electricity and heat has limited its economic viability [2-3]. Recent developments in gas-to-liquid (GTL) processes, specifically Fischer-Tropsch (F-T) synthesis, have shown promise in converting biogas into high-value liquid transportation fuels [2-3].

The Intensified Biogas to Liquid (IBGTL) process, developed at the University of South Florida, aims to overcome the economy of scale barrier in the production of liquid fuels from biogas. This process utilizes a hybrid catalyst system capable of combining endothermic bi-reforming with exothermic oxidation of methane and Fischer-Tropsch reactions into a single intensified process.

In this study, we conducted a techno-economic analysis (TEA) and life cycle assessment (LCA) of liquid fuel production from LFG via the IBGTL process. We compared the IBGTL process to the conventional biogas to liquid (BGTL) process and other classes of drop-in replacement fuels. A schematic comparison of the two processes is shown in Figure 1. The IBGTL reactor was modeled using Aspen Plus for a facility generating 2500 scfm of LFG, with CAPCOST employed for equipment costing and net present value and levelized cost of energy used for the economic analysis. SimaPro was used to conduct the LCA, with the system boundary and functional unit shown in Figure 2.

Our preliminary results show that the IBGTL process has a minimum fuel selling price (MFSP) of $6/GGE for Scenario 1 and $4/GGE for Scenario 2, which includes material recycle of excess fuel gas to the IBGTL reactor to increase liquid fuel yield. The TEA and LCA results provide insights into the economic and environmental feasibility of the IBGTL process, which can help in making informed decisions regarding its commercialization. The IBGTL process offers several advantages over the conventional BGTL process, such as reduced energy and material input, leading to reduced capital investments.

Further analysis is needed to fully evaluate the potential of the IBGTL process for large-scale commercialization. Additional scenarios and the carbon intensity of the various routes analyzed will be presented. Overall, the IBGTL process shows promise in converting LFG into high-value liquid transportation fuels, which can help decarbonize the transportation sector and contribute to the sustainable management of organic waste in landfills.

References

[1] IEA, Outlook for biogas and biomethane: Prospects for organic growth. IEA, Paris, 2020.

[2] Naqi, A., J.N. Kuhn, and B. Joseph, Techno-economic analysis of producing liquid fuels

from biomass via anaerobic digestion and thermochemical conversion. Biomass and

Bioenergy, 2019. 130 DOI: 10.1016/j.biombioe.2019.105395.

[3] Zhao, X., et al., Conversion of landfill gas to liquid fuels through a TriFTS (tri-reforming

and Fischer–Tropsch synthesis) process: a feasibility study. Sustainable Energy & Fuels,

2019. 3(2): p. 539-549 DOI: 10.1039/c8se00344k.