Overview
ISO 609:1996 - Solid mineral fuels - Determination of carbon and hydrogen - High temperature combustion method describes a laboratory high-temperature combustion procedure for determining the total carbon and total hydrogen in hard coal, brown coal, lignite and coke. The method burns a known mass of sample in oxygen at 1 350 °C, converts carbon to CO2 and hydrogen to H2O, absorbs the combustion products in reagents and determines amounts gravimetrically. Results include carbon in carbonates and hydrogen in moisture and structural water; corrections for moisture and mineral carbonates are described where applicable.
Key topics and technical requirements
- Scope: Applicable to hard coal, brown coal, lignite and coke; includes water determination during combustion and optional CO2 determination for carbonate correction.
- Principle: High-temperature combustion in an impervious tube with oxygen; absorption of H2O and CO2 by a series of reagents and gravimetric analysis.
- Reagents and materials: Typical reagents include magnesium perchlorate (for water), sodium hydroxide on an inert base (for CO2), alumina, sodium tetraborate titrant, hydrogen peroxide, and a mixed indicator. Safety warnings note toxic/corrosive reagents and special disposal/regeneration concerns (e.g., magnesium perchlorate).
- Apparatus: Furnace capable of 1 350 °C, refractory combustion tube, Midvale tubes or similar absorption train, combustion boats, silver gauze roll (to trap chlorine and sulfur oxides), flowmeters and a pusher for sample boats.
- Procedure essentials: Conditioning and calibration of absorption trains; locating and maintaining a silver gauze roll; burning a measured test portion and gravimetric measurement of absorbed products; applying corrections for moisture and carbonate-bound carbon.
- Quality control: Conditioning of Midvale tubes, periodic cleaning of silver gauze, limits on sulfur retention to avoid overloading the trap.
Applications and users
Who uses ISO 609:1996:
- Analytical laboratories performing coal analysis and quality control
- Power plants and utilities for fuel characterization and combustion optimization
- Coke producers and metallurgical operations monitoring feedstock composition
- Environmental reporting and carbon accounting where accurate fuel carbon/hydrogen data are required
- Research institutions comparing calorific properties and combustion behavior
Practical uses:
- Determining fuel composition for combustion efficiency and emissions estimates
- Routine quality control of coal and coke consignments
- Data input for heat value calculations and mass-balance studies
Related standards
Standards referenced in ISO 609:1996 include:
Keywords: ISO 609:1996, solid mineral fuels, carbon and hydrogen determination, high temperature combustion, coal analysis, coke testing, Midvale tube, silver gauze, laboratory combustion method.
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