The role of deep hydrocarbons in the global hydrocarbon budget

Time: Mon 2020-02-24 09.30

Location: Kollegiesalen, Brinellvagen 8, Stockholm (English)

Subject area: Energy Technology

Doctoral student: Daniil Kudryavtsev , Kraft- och värmeteknologi

Opponent: Professor Kostya Trachenko, Queen Mary University of London, United Kingdom

Supervisor: Associate professor Vladimir Kutcherov, Skolan för industriell teknik och management (ITM)

Abstract

Nowadays, the issue of global warming and related environmental problems got widespread awareness among scientific society, politics, the industry as well as it has affected our everyday life. The reason for such a negative impact on the atmosphere is attributed mainly to human activities. It is thought that one of the most dangerous greenhouse gases is carbon dioxide (CO2). Nevertheless, the problem of hydrocarbon emissions began to receive particular attention due to the exponential growth of methane emissions in the atmosphere. What is the reason for such behaviour and what about other hydrocarbons, first of all, ethane, propane and butane isomers? In this work, it was proposed that geological emissions, mainly the emission from the dissociation of natural gas hydrates is one of the main reasons for the dramatic rise in hydrocarbon emissions to the atmosphere. Natural gas hydrates are not only composed of methane and water cages but have in their structure a broad range of hydrocarbons, including ethane, propane, butanes and some others. 

The purpose of this thesis is to investigate the sources of non-methane volatile hydrocarbons in the atmosphere, examine their impact on the environment and explore the correlation of hydrocarbon emissions with CO2 emissions. 

To reveal the impact of natural gas hydrates to the hydrocarbon budget it was assumed, that hydrocarbons that are contributing to the natural gas hydrate formation have deep mantle origin. To confirm this hypotheses high-pressure high temperature investigation of propane and butanes were conducted. The results of this investigation are presented in this thesis. To model extreme thermobaric conditions the diamond-anvil cell technique with two-sided laser heating was used. The method of Raman spectroscopy was applied for the analysis. 

The results received show that propane and butane isomers stable in the pressure  up to 40 GPa at ambient temperature. Propane remains stable at temperatures up to 900 K. At temperatures >900 K chemical transformations of propane are starting to occur producing mixture of light alkanes.

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