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Questions and Answers
What is considered the rank (quality) of coal largely affected by?
What is considered the rank (quality) of coal largely affected by?
- Chlorine content
- Carbon content
- Sulfur content
- Moisture content (correct)
What is the correct order of mass fractions for the proximate analysis of Indian coal?
What is the correct order of mass fractions for the proximate analysis of Indian coal?
- Moisture 14%, Fixed carbon 31%, Volatile matter 21%, Ash 42% (correct)
- Ash 42%, Volatile matter 21%, Fixed carbon 31%, Moisture 14%
- Fixed carbon 31%, Ash 42%, Moisture 14%, Volatile matter 21%
- Volatile matter 21%, Ash 42%, Moisture 14%, Fixed carbon 31%
At what temperature should volatile matter in coal be analyzed?
At what temperature should volatile matter in coal be analyzed?
- 100°C
- 700°C
- 800°C
- 900°C (correct)
Which component's analysis requires the crucible to be closed with a lid during heating?
Which component's analysis requires the crucible to be closed with a lid during heating?
What is the dwell time for ash analysis in the furnace?
What is the dwell time for ash analysis in the furnace?
How can the mass fraction of moisture, Y_M, be expressed mathematically?
How can the mass fraction of moisture, Y_M, be expressed mathematically?
Which mass fraction formula accounts for the fixed carbon content?
Which mass fraction formula accounts for the fixed carbon content?
What is the correct calculation to find the ash content, Y_A?
What is the correct calculation to find the ash content, Y_A?
What is the primary difference between Y_VM and Y_M?
What is the primary difference between Y_VM and Y_M?
In finding Y_VF, which step needs to be taken after determining Y_M?
In finding Y_VF, which step needs to be taken after determining Y_M?
Which component of coal primarily determines its calorific value?
Which component of coal primarily determines its calorific value?
How does excessive moisture content in coal affect its use?
How does excessive moisture content in coal affect its use?
What is referred to as the 'gross calorific value' of a fuel?
What is referred to as the 'gross calorific value' of a fuel?
Which of the following increases with the rank of coal?
Which of the following increases with the rank of coal?
Why do components other than carbon and hydrogen decrease the rank of coal?
Why do components other than carbon and hydrogen decrease the rank of coal?
Ash content in coal primarily consists of which materials?
Ash content in coal primarily consists of which materials?
The products of combustion from carbon and hydrogen in coal are primarily what substances?
The products of combustion from carbon and hydrogen in coal are primarily what substances?
What effect does high ash content have on furnace efficiency?
What effect does high ash content have on furnace efficiency?
Study Notes
Proximate Coal Analysis
-
Aim: To determine the composition of a coal sample by measuring its moisture, volatile matter, ash, and fixed carbon content.
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Key Components:
- Moisture: Water content in coal, impacting transportation cost and combustion efficiency.
- Volatile Matter: Components released when coal is heated in the absence of oxygen, decreasing the coal's rank.
- Ash: Inorganic matter in coal, reducing combustion efficiency.
- Fixed Carbon: The remaining combustible material after volatile matter is removed, increasing with coal rank.
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Proximate Analysis vs. Ultimate Analysis:
- Proximate analysis: determines the mass fractions of moisture, volatile matter, ash, and fixed carbon.
- Ultimate analysis: determines the mass fractions of elements like C, H, O, N, S, Cl, etc.
Procedure
- Steps:
- Weigh an empty crucible.
- Add a known mass of coal sample to the crucible and weigh it again.
- Place the crucible in a furnace at specific temperatures and dwell times for each component:
- Moisture: 100°C, 60 minutes
- Volatile matter: 900°C, 10 minutes
- Ash: 700°C, 60 minutes
- Allow the crucible to cool in a desiccator and weigh the residue.
- Repeat steps 1-4 to analyze each component.
Calculation
- Mass fractions are calculated using the following formulas:
- YM: Moisture content = 1 - (Residue massExpt.1 / Sample massExpt.1)
- YVM: Volatile matter content = 1 - (Residue massExpt.2 / Sample massExpt.2) - YM
- YFC: Fixed Carbon content = 1 - (Residue massExpt.3 / Sample massExpt.3) - YM - YVM
- YA: Ash content = 1 - YM - YVM - YFC
Results
- Proximate analysis provides the following information:
- Moisture content (in %)
- Volatile matter content (in %)
- Fixed Carbon content (in %)
- Ash content (in %)
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Description
Test your knowledge on proximate coal analysis and its key components such as moisture, volatile matter, ash, and fixed carbon. Understand the differences between proximate and ultimate analysis while learning about the significance of these factors in coal composition and combustion efficiency.
