Carnegie Mellon University
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Assessing the Impacts of Mineral and Hydrocarbon Resources Exploitation and Consumption

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posted on 2017-10-01, 00:00 authored by Yu Gan

The exploitation of natural resources lays the foundation for the economic and social development, but also is the root cause of various environmental issues. The study aims to analyze the process of natural resource exploitation, to optimize the extraction and utilization processes, maximizing their economic and social values while reducing the accompanied negative environmental impacts. This dissertation focuses on the impacts of exploitation of mineral and hydrocarbon resources in emerging countries on global warming effect, economy and society. Chapter 2 of the dissertation analyzes the life cycle GHG emissions associated with iron ore mining and processing in China. With rapid economic development and nationwide urbanization, the iron ore demand grows while the ore grade declines significantly, leading to the increasing GHG emissions from iron ore production. Results of the research show that the mean life-cycle GHG emissions for Chinese iron ore production are 270 kg CO2e/tonne, with a 90% confidence interval of 210 to 380 kg CO2e/tonne. The two largest contributors to overall GHG emissions are agglomeration (60%) and ore processing (23%). Iron content (ore grade) varies from 15% to 60% and is the largest contributor (40%) to the uncertainty of the results. Chapter 3 explores the impact of China’s outsourcing of iron resources on the global warming effect. This chapter applies the same life cycle assessment framework of Chinese iron ore in Chapter 2 to Australian and Brazilian ore production, and compares the LCA results of Australian and Brazilian ore to Chinese iron ore. Results show that among the three iron ore sources, Australian iron ore is the optimal choice for reducing GHG emissions. The mean life cycle GHG emissions of Australian iron ore fines is 60% less than that of Chinese iron ore fines (42 kg CO2e/tonne versus 110 kg CO2e/tonne). There is no significant difference between the imported iron ores sourced from Brazil versus the China’s domestic supplied iron ores, but if Chinese ore grade falls below 20% in the future, Brazilian iron ores would be preferred. The largest source of GHG emissions for Australian and Brazilian iron ores comes from ocean shipping (accounts for 58% and 75% of the overall GHG emissions respectively). Chapter 4 studies the impacts of the exploitation of pre-salt natural gas in Brazil. Natural gas production and its associated downstream industries are currently underdeveloped in Brazil, while the on-going exploitation of deep-sea pre-salt reservoir would potentially change the current situation. This study analyzes the impacts of the increasing pre-salt gas production and potential natural gas use pathways in downstream industries. Results reveal that GHG emissions associated with pre-salt gas production vary according to the stage of reservoir exploitation. At the early stage, the estimate of GHG emissions is 5.4 (90%CI: 4.5~6.4) gCO2e/MJ, and the value becomes 7.1 (90% CI: 6.3~8.0) gCO2e/MJ for the intermediate stage. All six natural gas use pathways analyzed in the study emit less GHG on average than their current corresponding incumbent pathways. The mean GHG emissions reduction from natural gas use for power generation, nitrogen fertilizer production, methanol production, as the reducing agent for steel making, ethylene-based polymer production, heavy-duty vehicle fueling are estimated to be 0.83, 2.3, 0.38, 35, 2.6 and 0.078 million tonnes CO2 equivalent per year, respectively. The specific economic profits of the six pathways are affected by the prices of natural gas and traditional fuel. Under current fuel prices, the net annual profits for the six pathways are -270, 87, 92, 1700, 190 and -1500 million dollars, respectively. The job creation potential from the pathways of power generation, nitrogen fertilizer production, methanol production and as reducing agent for steel production are estimated to be 28, 17, 5 and 36 thousand, respectively.

History

Date

2017-10-01

Degree Type

  • Dissertation

Department

  • Engineering and Public Policy

Degree Name

  • Doctor of Philosophy (PhD)

Advisor(s)

W. Michael Griffin

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