Understanding the standardized approach for calculating carbon inputs and outputs in blast furnace operations to optimize efficiency and reduce emissions.
The carbon balance methodology defined in ISO 14404:2024 provides a systematic approach for calculating greenhouse gas emissions from steel production through blast furnace routes.
The fundamental concept that carbon input must equal carbon output, accounting for all transformation processes within the system boundary.
Clearly defined boundaries for the blast furnace process, including all material inputs, energy carriers, and emission outputs.
Uniform methodology ensuring comparability across different facilities and enabling accurate benchmarking of performance.
The step-by-step approach to calculating carbon flows according to ISO 14404:2024 standards.
Establish the physical and process boundaries for the carbon balance calculation, typically including the blast furnace proper and its direct auxiliaries.
Quantify all carbon-containing materials entering the system boundary, including both reducing agents and other carbon sources.
Where Ccoke is carbon from metallurgical coke, CPCI is carbon from pulverized coal injection, and Cother includes other carbon sources.
Account for all carbon leaving the system boundary, including products, by-products, and emissions.
Where CHM is carbon in hot metal, Cslag is carbon in slag, Cgas is carbon in top gas, and Cdust is carbon in dust emissions.
Apply the mass balance principle to ensure carbon inputs equal carbon outputs, accounting for any accumulation within the system.
Where ΔCstorage represents changes in carbon stored within the system (typically negligible over measurement periods).
A practical example demonstrating the carbon balance calculation for a typical blast furnace operation.
Based on operational data from a 24-hour period for production of 10,000 tonnes of hot metal.
| Carbon Inputs | Quantity | Carbon Content | Total Carbon |
|---|---|---|---|
| Metallurgical Coke | 4,200 t | 85% | 3,570 tC |
| PCI Coal | 1,450 t | 75% | 1,088 tC |
| Other Carbon Sources | 150 t | 80% | 120 tC |
| Total Carbon Input | 4,778 tC |
| Carbon Outputs | Quantity | Carbon Content | Total Carbon |
|---|---|---|---|
| Hot Metal | 10,000 t | 4.5% | 450 tC |
| Top Gas | 18,500,000 Nm³ | 22% CO₂ | 3,640 tC |
| Slag | 2,800 t | 0.5% | 14 tC |
| Dust & Losses | 120 t | 10% | 12 tC |
| Total Carbon Output | 4,116 tC |
Carbon Input: 4,778 tC | Carbon Output: 4,116 tC
Carbon Balance Discrepancy: 662 tC (13.9% of input)
This discrepancy indicates measurement inaccuracies or unaccounted carbon flows that require investigation.
Carbon efficiency, specific emission factor, and carbon utilization rate are critical KPIs derived from carbon balance calculations.
ISO 14404:2024 specifies the data quality, documentation, and reporting standards for carbon balance calculations.
Carbon balance analysis identifies opportunities for process improvements, energy savings, and emission reductions.