Main-Product

Nitrogen is an important contaminant in crude oil, typically found in the form of organic nitrogen compounds. These compounds can be basic, such as R-Quinolines, R-Pyridines, and Carbazoles, which are released when crude oils are treated with acid. Basic nitrogen compounds are particularly undesirable in crude oil fractions as they deactivate the acidic sites on catalysts used in conversion processes and can be corrosive. Crude oils with nitrogen contents greater than 0.25%wt need treatment in refineries for nitrogen removal.

The presence of these nitrogen compounds can inhibit the dissolution of minerals during acid stimulation processes, reducing the efficiency of matrix acidification and oil recovery. For instance, the presence of small amounts of nitrogen-organic compounds (N.O.C) in the aqueous phase can inhibit up to 72% of the elements released by mineral dissolution, likely due to the shielding of the mineral surface active sites.

The nitrogen compounds found in fossil hydrocarbons exist in different physical states depending on their molecular structure and complexity:

Basic Nitrogen Compounds

• Liquid State
  • Pyridines and their derivatives
  • Quinolines
  • Anilines
  • Most basic nitrogen compounds are found in liquid fractions

Non-Basic Nitrogen Compounds

• Solid and Liquid States
  • Carbazoles (solid)
  • Indoles (liquid/solid)
  • Phenylpyrroles (liquid)

Distribution Characteristics

The nitrogen compounds are typically found in:

• Light-oil fractions (liquid state)
• Middle-oil fractions (liquid state)
• Heavier fractions (higher molecular weight compounds, typically solid)

Concentration Patterns

These compounds are predominantly found in:

• Liquid coal tar (1-2% nitrogen content)
• Liquid shale oil (1-2% nitrogen content)
• Liquid petroleum (0.05-0.1% nitrogen content)

Physical State

Most nitrogen compounds in fossil hydrocarbons are found in liquid form at room temperature, particularly in the oil fractions, though some heavier molecular weight compounds can exist as solids.

References

1. Brave search, 1^st Jan 2025, Prompt: 'nitrogen contaminants in crude oil'.
2. Perplexity A.I. search, 1st Jan 2025, Prompt: 'Can you provide information about nitrogen bearing compounds found in fossil hydrocarbons?' and other prompts.