GB/T 45862-2025 in English

Interpretation of the core content of the national standard GB/T 45862-2025

As a milestone document in the field of boiler carbon emission measurement, this standard systematically constructs a methodology system for boiler carbon emission testing and calculation for the first time. The standard is applicable to boilers burning fossil fuels, boilers mixed with/purely burning non-fossil fuels, and electric heating boilers, and explicitly excludes the applicability of waste incineration boilers and waste heat boilers.

Analysis of standard framework and technological evolution

This standard inherits and develops the methodology of thermal testing standards such as GB/T 10180 and GB/T 10184, and innovatively combines carbon emission measurement with traditional thermal testing. The background of standard formulation is consistent with the needs of my country's "dual carbon" strategy, and reflects the technological evolution path from single thermal efficiency assessment to comprehensive carbon efficiency evaluation.

Analysis of Key Terminology

The standard establishes a comprehensive terminology definition system, with particular attention paid to:

Boiler System (3.1): This encompasses the complete system of boilers, fans, pumps, water treatment systems, and other auxiliary equipment. This definition expands the scope of traditional boilers.

Direct Carbon Emissions (3.2): This encompasses carbon dioxide emissions from fuel combustion and flue gas treatment processes (desulfurization, denitrification, etc.), reflecting the concept of a full-process carbon footprint.

Carbon Emission Intensity (3.5): The total amount of carbon emissions per unit of heat output, a core indicator for evaluating boiler carbon efficiency.

Test Boundary Delineation and Emission Source Identification

The standard uses Figures 1-4 to provide detailed schematic diagrams of the test boundaries for four typical boilers. The test boundaries are divided into two categories:

Boiler Boundary: This corresponds to the thermal balance system boundary for boiler energy efficiency testing and is applicable to product carbon emissions testing.

Boiler System Boundary: This encompasses all auxiliary equipment and is applicable to operational and acceptance carbon emissions testing.

As a carbon-neutral fuel, CO₂ emissions from the combustion of biomass fuel are not included in carbon emissions, but must be stated in the test report. This requirement reflects the policy's support for renewable energy.

Test Requirements and Quality Control

The standard stipulates strict testing conditions: carbon emissions testing must be conducted simultaneously with energy efficiency testing. Detailed test duration and frequency requirements for different boiler types are shown in Table 2 of the standard. Test result deviation control requires that the relative deviation of carbon emission intensity under each operating condition be no more than 3%, ensuring data reliability and comparability.

Strict stability requirements are imposed on test conditions, and fluctuations in key thermal parameters must be kept within acceptable limits. Condensing boilers must comply with NB/T 47066, industrial boilers with GB/T 10180, and power plant boilers with GB/T 10184.

Measurement Items and Instrument Specifications

In addition to conventional energy efficiency test items, carbon emissions testing includes three new measurement items:

1. Flue gas flow measurement, using a flow meter and a flue cross-section measuring instrument

2. Flue duct static pressure measurement, using a static pressure probe

3. Auxiliary power consumption measurement, using a electricity meter

All instruments must be within the verification or calibration period and meet the corresponding range and accuracy requirements.

Carbon Emission Calculation Method System

8.1 Calculation of Total Carbon Emissions

Use formula (2): E = E_d + E_id, where direct carbon emissions E_d are determined by the emission factor method and verified by the measurement method. When the difference Δ between the two is greater than 5%, the operating condition is invalid.

8.2 Calculation of Direct Carbon Emissions

Emission factor method: Calculate by fuel consumption and emission factor. Solid and liquid fuels use formula (6), gas fuels use formula (8), and biomass-blended fuels use formulas (7) and (9).

Measurement method: Calculate by measuring flue gas CO₂ concentration and flow rate. Use formula (18). Biomass-blended boilers use formulas (19)-(21).

Carbon oxidation rate calculation uses formulas (10)-(13) depending on the fuel type. This is a key parameter for accurate calculation.

8.3 Calculation of indirect carbon emissions

Use formula (32): E_id = (AD_e × EF_e)/T, where the total electricity consumption AD_e is subdivided into overcoming smoke and wind resistance, working fluid flow resistance, fuel preparation, and other electricity consumption according to formula (33).

The electricity carbon emission factor EF_e uses the latest data released by the national competent authorities, reflecting policy guidance.

8.4 Calculation of carbon emission intensity

It is divided into boiler carbon emission intensity E_a (formula 37) and boiler system carbon emission intensity E_a.s (formula 38). According to the output heat type, the output heat Q is calculated using formulas (41)-(51).

8.5 Correction of direct carbon emission intensity

Product testing needs to be corrected to the design conditions. Formulas (52) and (57) are used to introduce the correction coefficient ψ_c based on carbon in the fuel and the correction coefficient ψ_s based on sulfur.

Test Report Specification Requirements

The test report must include complete information: test boiler model, commissioning organization, test location, date, testing organization, and test number. The main body should detail the test purpose, responsible person, measurement point layout, instrument description, operating conditions, and results analysis. Raw data must be archived for at least four years.

Implementation Recommendations and Notes

1. Pre-test Preparation: Fully understand the test boundary demarcation and accurately identify emission sources, especially special treatments for biomass co-firing.

2. Instrument Selection: Strictly select measuring instruments according to the accuracy levels required by the standard, especially flue gas analyzers and flow meters.

3. Data Processing: Pay attention to unit consistency and standard state conversion. All cubic meters refer to volumes under standard conditions (0°C, 101325Pa).

4. Quality Control: Strictly implement the Δ<5% calibration requirement to ensure consistency between the emission factor method and the measurement method.

5. Report Preparation: Completely record the test process and original data to ensure data traceability and reviewability.

The implementation of this standard will significantly improve the standardization and accuracy of carbon emissions measurement in my country's boilers, provide technical support for carbon trading and verification, and promote the low-carbon transformation of the boiler industry.