Mercury in Indian Thermal Coals

Area of Science:

• Environmental Science
• Geochemistry
• Energy Resources

Background:

• Coal combustion is a significant anthropogenic source of mercury (Hg) emissions globally.
• In India, coal power generation represents the largest contributor to national mercury pollution.
• Understanding mercury content in Indian coals is crucial for emission control strategies.

Purpose of the Study:

• To determine the mercury concentrations in Indian sub-bituminous and bituminous coals.
• To assess the relationship between mercury content and various coal rank parameters.
• To provide data for evaluating mercury emissions from Indian coal-fired power plants.

Main Methods:

• Collection of 165 coal samples from major Indian coal-producing regions.
• Analysis of mercury content using established methods.
• Characterization of coal samples for parameters including moisture, ash, volatile matter, total sulfur, and gross calorific value.

Main Results:

• Mercury concentrations in the analyzed coals varied from 3 to 554 µg/kg, with a mean of 175 µg/kg.
• No significant correlations were found between mercury content and coal rank parameters (volatile matter, carbon content, total sulfur).
• A discernible trend of increasing mercury content with rising ash content was observed.

Conclusions:

• Indian coals exhibit a wide range of mercury concentrations relevant to power generation.
• Coal rank is not a primary determinant of mercury content in these coals.
• Ash content may serve as a potential indicator for higher mercury levels in Indian coals, aiding in emission management.