1 Introduction
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Statutory Documents - IMO Publications and Documents - International Codes - NOx Technical Code - Technical Code on Control of Emission of Nitrous Oxides from Marine Diesel Engines - Appendix 6 - Calculation of exhaust gas mass flow (carbon-balance method) - 1 Introduction

1 Introduction

  1.1 This appendix addresses the calculation of the exhaust gas mass flow and/or of the combustion air consumption. Both methods given in the following are based on exhaust gas concentration measurement, and on the knowledge of the fuel consumption. Symbols and descriptions of terms and variables used in the formulae for the carbon-balance measurement method are summarized in table 4 of the Abbreviations, Subscripts, and Symbols of this Code.

  1.2 This appendix includes two methods for calculating the exhaust gas mass flow as follows: method 1 (carbon balance) is only valid using fuels without oxygen and nitrogen content; and, method 2 (universal, carbon/oxygen-balance) is applicable for fuels containing H, C, S, O, N in known composition.

  1.3 Method 2 provides an easily understandable but universal derivation of all formulae including all constants. This method is provided because there are many cases where the present available constants, neglecting essential parameters, may lead to results with avoidable errors. Using the formulae within method 2, it may also be possible to calculate the essential parameters under conditions deviating from standard conditions.

  1.4 Examples of parameters for some selected fuels are offered in table 1. The values for fuel composition are for reference purposes only and shall not be used in place of the composition values of the oil fuel actually used.

Table 1 Parameters for some selected fuels (examples)

Fuel C % H % S % O % EAF FFH FFW FFD EXHDENS
Diesel 86.2 13.6 0.17 0 1

 1.835

 0.749 -0.767 1.294

2
        1.35 1.865     1.293
        3.5 1.920     1.292
RME 77.2 12.0   10.8 1 1.600 0.734 -0.599 1.296
       
1.35
1.63 		    1.295
       
3.5
1.685 		    1.292
Methanol 37.5 12.6 0 50.0 1

 1.495
 1.046 -0.354 1.233
        1.35
1.565 		   
1.246
        3.5 1.705     1.272
Ethanol 52.1 13.1 0 34.7 1 1.65 0.965 -0.49 1.26
       
1.35
1.704 		    1.265
       
3.5
1.807 		    1.281
Natural gas* 60.6 19.3 0 1.9 1 2.509
 1.078 -1.065 1.257
       
1.35
2.572 		   
1.265
       
3.5 		2.689     1.28
Propane 81.7 18.3 0 0 1 2.423
 1.007 -1.025 1.268
       
1.35
2.473 		   
1.273
       
3.5 		2.564    
1.284
Butane 82.7 17.3 0 0 1

 2.298
 0.952 -0.97 1.273
        1.35
2.343 		    1.277
        3.5 2.426     1.285
* Volumetric composition: CO2 1.10%; N2 12.10%; CH4 84.20%; C2H6 3.42%; C3H8 0.66%; C4H10 0.22%; C5H12 0.05%; C6H14 0.05%.

  1.5 Except as otherwise specified, all results of calculations required by this appendix shall be reported in the engine's test report in accordance with section 5.10 of this Code.

Parent topic: Appendix 6 - Calculation of exhaust gas mass flow (carbon-balance method)
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