## Oil Shale Chemical Characteristic
### Oil Shale Pyrolysis  
#### 4.2.1 Oil Shale Pyrolysis Process  
Pyolysis of oil shale is a thermochemical decomposition conducted under oxygen-free conditions, which induces complex reactions and transforms kerogen in shale into hydrocarbons. Shale constitutes diverse organic composites, including high C/H ratio components and heteroatomic species (i.e., sulfur, nitrogen, oxygen).  
Heteroatomic compounds, notably those with sulfur and nitrogen, can present challenges, leading to diminished fuel stability, increased nitrogen oxide emissions, and storage complications.  
The pyrolysis procedure typically necessitates oil shale heating in a tube furnace to approximately 480 \({}^{\circ}\)C. This thermal cracking process, also referred to as \"viscosity breaking,\" improves oil quality by lowering the pour point. The oil then undergoes coking and rectification.  
Subsequent treatment of the resultant oil can enhance gasoline and other distillate yields. A notable approach involves recycling, which reintroduces rectification column residues into the system.  
Advancements in pyrolysis processes and the development of new oil shale conversion techniques demand comprehensive study. This includes exploring rapid heating conditions for shale feedstock and secondary pyrolysis techniques, primarily focusing on catalytic hydrofining for heteroatomic compound elimination, specifically sulfur and nitrogen [54].  
According to data from 2020, the oil shale market was valued at an estimated USD 2.8 billion, and projections suggest it could approximately double by the year 2030. Nonetheless, it is essential to recognize the inherent limitations of oil shale as a lower-tier energy commodity, which only becomes economically viable subsequent to undergoing rigorous mining and retorting processes. Take the Green River Formation in Colorado as an example, where roughly a ton of oil shale is needed to yield a mere 0.83 US barrels of oil. The actual utilizable organic matter encapsulated within the shale accounts for just one-fifth of its total weight. The remaining four-fifths, once extracted, poses formidable environmental challenges. As such, addressing these environmental implications is a vital aspect that warrants due consideration (source: [[https://www.alliedmarketresearch.com/oil-shale-market](https://www.alliedmarketresearch.com/oil-shale-market)]([https://www.alliedmarketresearch.com/oil-shale-market](https://www.alliedmarketresearch.com/oil-shale-market)) (accessed on 26 June 2023)).  
Current technological advancements have certainly fostered growth in mining and surface mining operations. However, the pathway toward large-scale expansion remains fraught with obstacles. In terms of cost, figures from 2010 suggest a range of USD 70-USD95 per barrel. In situ methods have indeed demonstrated potential via small-scale tests in certain locales, yet environmental considerations might present additional concerns. Even though the costs associated with in situ methods are predicted to undercut those of mining and surface mining, the dearth of publicly available data imposes difficulty in drawing definitive conclusions (source: [[https://scholar.law.colorado.edu/cgi/viewcontent.cgi?](https://scholar.law.colorado.edu/cgi/viewcontent.cgi?)]([https://scholar.law.colorado.edu/cgi/viewcontent.cgi?](https://scholar.law.colorado.edu/cgi/viewcontent.cgi?)) article=1003&context=promise-and-peril-of-oil-shale-development (accessed on 26 June 2023)).