Detailed Input Method (A2) - Input CO2 Balance
The detailed input method (A2) accounts for CO2 emissions from the organic carbon content (TOC) of raw materials and the calcination of bypass dust, CKD leaving the kiln system.
Please also see the Protocol Guidance Document (Chapter 3.3).
The following diagram illustrates the flow of mass and dust in a cement plant.
Figure 4: Diagram of the detailed input method (A2)
The names of mass flows in the diagram directly relate to the reporting with the calcination sheet CalcA2:
- The section Raw meal in the calcination sheet contains the information on the amount of kiln feed, its correction for dust return and the analysis of the total CO2 released from TC of the raw meal. See the additional information on the determination of dust return correction regarding input methods (A1) and (A2).
Line600 to line603 calculate the calcination of raw meal consumed, in order to prevent double counting of the recycled part of the kiln feed. The corresponding amount of CO2 is determined based on the CO2 released from TC2 of the raw meal (RM). The complete CO2 emissions of the raw meal must be determined. This can be done e.g. by total carbon (TC) analysis (or CO2 IR-analysis of the gases released from the heated and fully oxidised sample). - The section Additional raw material # 1 (not part of kiln feed) (#1 - #10; # = number) contains the amount of additional raw materials and the analysis of their CO2 released from TC.
- The section bypass dust correction for uncalcined fraction refers to the amount of bypass dust and its residual CO2 from total carbon in the diagram.
- The section CKD leaving the kiln system in the calcination sheet refers only to the amount of cement kiln dust (CKD) and its CO2 released from TC that is not recycled to the kiln feed in the diagram.
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Lines 671 to 676 determine the total CO2 emissions from the calcination of raw materials (TIC) and from their organic carbon content (TOC).
Calculation Details
Equation for the detailed input method (A2) as implemented in the auxiliary sheet CalcA2:
Equation 4: Detailed Input Method (A2)
where:
- CO2 Raw Materials = total CO2 from raw materials (t CO2/yr), Plant sheet 039
- Kiln Feed = amount of kiln feed measured at plant level (t/yr)
- Dust Return Correction = fraction of returned dust with reference to the Kiln Feed
- fCO2RM = weight fraction of CO2 released from TC3 in the raw meal
- CKD leaving kiln system = amount of cement kiln dust leaving the kiln system (t/yr)
- EFCKD = CO2 emission factor of partially calcined cement kiln dust (t CO2/t CKD) based on TC
- BypassD leaving kiln system = amount of bypass dust leaving the kiln system (t/yr)
- fCO2BypassD = weight fraction of CO2 released from TC in the bypass dust
- ARMi = amount of additional raw material i (t/yr), which is not part of the Kiln Feed
- fCO2ARM,i = weight fraction of CO2 released from TC in the additional raw material i
In the case of using the values from a CaCO3 and MgCO3 analysis, the CO2 emissions from the total organic carbon content (TOC) of the raw materials consumed must be added manually in order to determine the correct input values for the CO2 released from TC and the "Total CO2 from raw materials" (line676) according to the detailed input method (A2).
Equation 5: Total CO2 from raw material
where:
- fCO2 = weight fraction of carbonate CO2 (%)
- CaCO3, MgCO3 = relative amount of elements (%)
- Total Organic Carbon (TOC) = relative amount of organic carbon (%)
- MCaCO3 = 100.087 g/mol (*)
- MMgCO3 = 84.314 g/mol (*)
- MC = 12,010 g/mol (*)
- MCO2 = 44,010 g/mol (*)
* Please also see List of Constants and Default CO2 emission factors
The CO2 released from inorganic carbon of the input materials and CKD and bypass dust leaving the kiln system can alternatively be determined from CaCO3 and MgCO3 analysis (CO2 from total inorganic carbon, TIC). In this case the CO2 emissions from the organic carbon content (TOC) of the raw materials consumed must be added manually to determining the input values for lines 602, 611, 614, 617, etc. in order to account for the complete CO2 emissions (CO2 from total carbon content TC = TIC+TOC).
Please note:
- The resulting "Total CO2 from raw materials" in line 671 and 676 should in any case account for CO2 emissions from the total carbon (TC, including CO2 from organic carbon) content of raw materials according to the detailed input method (A2).
- CO2 emissions from TIC and TOC of additional raw materials (ARM), which are not part of the kiln feed, should be accounted for by filling in lines 610 to 639 as appropriate.
- The CO2 emissions from the organic carbon content (TOC) of additional raw materials are correctly accounted for in lines 610 to 639 by specifying the complete CO2 emissions.
- As for raw meal, this can be done e.g. by total carbon (TC) analysis (or CO2 IR-analysis of the gases released from the heated and fully oxidised sample).
Adjustments to the concept of the input method: In special cases an adjustment of the concept of the input methods might be necessary in order to reflect certain material flows in a plant and to ensure that they are correctly accounted for. In this case, the corresponding adjustments should be made in a customised auxiliary sheet, not in the plant sheet. The adjustments should be explained, and accompanied by an overview of all relevant material flows. Furthermore it should be demonstrated that CO2 emissions from the complete and partial calcination of raw materials and from the organic carbon content of raw materials are completely and more accurately accounted for by the adjusted method.
Please also see the Protocol Guidance Document (Chapter 3.3).
An alternative method of accounting for CO2 emissions from additional raw materials with very high organic carbon content (TOC) is described in the Protocol Guidance Document.
Where to put the results from the calcination sheet
Please see task Integrate the results of the Calcination sheet into the Plant sheet for further information on how to transfer the results from the output line(s) of your calculation from a calcination sheet into the corresponding Plant sheet.
Please note that the calcination sheet(s) will not be checked by the automatic validation tool.