Gas to Liquids Techno-Economics of Associated Natural Gas, Bio Gas, and Landfill Gas

Federico Galli,Jun-Jie Lai,Gianluca Pauletto,Jacopo De Tommaso,Gregory S Patience

doi:10.3390/pr9091568

Federico Galli, Jun-Jie Lai + Show 3 more

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https://doi.org/10.3390/pr9091568

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Abstract

Methane is the second highest contributor to the greenhouse effect. Its global warming potential is 37 times that of CO2. Flaring-associated natural gas from remote oil reservoirs is currently the only economical alternative. Gas-to-liquid (GtL) technologies first convert natural gas into syngas, then it into liquids such as methanol, Fischer–Tropsch fuels or dimethyl ether. However, studies on the influence of feedstock composition are sparse, which also poses technical design challenges. Here, we examine the techno-economic analysis of a micro-refinery unit (MRU) that partially oxidizes methane-rich feedstocks and polymerizes the syngas formed via Fischer–Tropsch reaction. We consider three methane-containing waste gases: natural gas, biogas, and landfill gas. The FT fuel selling price is critical for the economy of the unit. A Monte Carlo simulation assesses the influence of the composition on the final product quantity as well as on the capital and operative expenses. The Aspen Plus simulation and Python calculate the net present value and payback time of the MRU for different price scenarios. The CO2 content in biogas and landfill gas limit the CO/H2 ratio to 1.3 and 0.9, respectively, which increases the olefins content of the final product. Compressors are the main source of capital cost while the labor cost represents 20–25% of the variable cost. An analysis of the impact of the plant dimension demonstrated that the higher number represents a favorable business model for this unit. A minimal production of 7,300,000 kg y−1 is required for MRU to have a positive net present value after 10 years when natural gas is the feedstock.

Highlights

Since 2018, USA has produced more than 10 million bbl d−1 of crude oil [1], whileCanada produces half of that
We simulate the micro-refinery unit (MRU) process with ASPEN Plus and developed a Python code to conduct an economic analysis [37].We study the techno-economic analysis of the application of the MRU for treating biogas, natural gas, and landfill gas
The MRU is only economical when we discount the carbon tax for the avoided flaring, with a payback time ranging from (0.71 ± 0.11) y to (0.66 ± 0.09) y depending on the product price assumed

Summary

Introduction

Since 2018, USA has produced more than 10 million bbl d−1 of crude oil [1], while. At a price of 75 USD bbl−1 (July 2021), crude oil remains an important source of revenue for these countries. Regardless of the technology used to recover the oil, pumps extract natural gas with the oil. The prohibiting costs of infrastructure (installing gas purification stations as pipelines and a compressor) make venting or flaring the preferred alternative for remote wells. Methane is the second highest contributor to greenhouse gases, accounting for 16% of global emissions after carbon dioxide (65%) [2], and its global warming potential is 37 ± 10 times more than that of carbon dioxide over a 100-year period [3].

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