Energy per Cement Output

Transcription

1 Energy per Cement Output Zhang J T National Institute of Metrology

2 1. Background and vision Background electricity homogenization Coal heating preheating Cement ore Crush powdering Clinker storage additives Clinker cooling Cement grinding Rotary furnace Dust absorber Cement products

3 Energy Efficiency per Output Comprehensive standard coal consumption per clinker product e cl N i 1 M i m1 m2 Qnet,ar Q BM P CL i (1) Q BM calorific value of standard coal Q net,ar net calorific value of coal measured at the entrance P CL M m i gross output of clinker output of clinker coal at the storage counting number of the batch of incoming coal

4 Vision by a critical metrologist quantity Comparable quantity Practically poor Measurement or calculation in consistent procedure Inconsistency hasn t been evaluated Causes for inconsistency Place to measure coal Procedure to measure calorific value of coal

5 2. Metrology problem Weighing coal Why Place important Loss of mass and heat value during stock Difficulty to calibrate belt balance Where to weigh coal

6 Measuring calorific value of coal Place to collect samples for measuring calorific value Procedure for measuring calorific value Calorific value of coal in full combustion: x2 x4 Cx H 1 x O N S O 2 x3 x4 x y 5 2 zh2o x1co 2 ( z)h2o N2 x5so Calorific value relates to the contents of water, ash and fugitive constituents

7 Proximate analysis of coal Principle: calorific value of coal is connected to the contents of water, ash and fugitive constituents Anthraciferous coal Q V A 563.0M net,ad ad ad ad Bituminous coal Q V A 702.0M 173.6CRC net,ad ad ad ad Lignitous coal CRC Characteristic of Non-volatile residue The empirical relation results in the uncertainty around 2.9 %

8 Bomb calorimetry Gross calorific value Direct measurement Convenient operation

9 Calorific value(j/g) 3. Comparison between the results by both procedures Reference sample I The average of measurements deviates from the reference value in 6.1 %. The dispersion is in the relative deviation of 1.4 % The average of measurements deviates from the reference value in -0.4 %. The dispersion is in the relative deviation of 0.9 %

10 Calorific value(j/g) Reference sample II The average of measurements deviates from the reference value in 0.92 %. The dispersion is in the relative deviation of 0.6 % The average of measurements deviates from the reference value in %. The dispersion is in the relative deviation of 0.7 %

11 Calorific value(j/g) Reference sample III The average of measurements deviates from the reference value in 0.01 %. The dispersion is in the relative deviation of 0.6 % The average of measurements deviates from the reference value in %. The dispersion is in the relative deviation of 0.5 %

12 4. Uncertainty budget for procedure If uncertainty for measurement with each batch remains invariant Stands for the uncertainty with measuring calorific value of one batch of coal Stands for the uncertainty with weighing one batch of coal u PCL Stands for the uncertainty with weighing clinker product Comparing to M i, (m 1 m 2 ) is too little to make significant contribution to u cl

13 Weighing coal The upper bound error for track scale and truck scale Measuring calorific value uncertainty: net,ar a)the non-uniformity of fossil fuel sampling u u Q u Q Q b)the uncertainty from determining calorific value Uncertainty because of non-uniformity Ash(A d ) % Rang of calorific value MJ/kg Uncertainty by non-uniformity % > 28 < 1.2

14 Uncertainty from determining calorific value Proximate analysis of coal Ash(A d ) % Nonuniformity, % Dispersion of different measureme nts, % Deviation from reference value, % Uncertainty with the empirical equation, % Combine uncertainty, % < < ( ) Bomb calorimetry Ash(A d ) % Nonuniformity, % Dispersion of different measureme nts, % Deviation from reference value, % Measurement repeatability single sample % Combine uncertainty, % < < ( )

15 Uncertainty budget for comprehensive standard coal consumption per clinker product Proximate analysis of coal ash (A d,%) contribution(%) Combined uncertainty Calorific value Coal mass Clinker product < ( ) < ( )

16 Bomb calorimetry ash (A d,%) contribution(%) Combined uncertainty Calorific value Coal mass Clinker product < ( ) < ( )

17 Comparable standard coal consumption per cement product E g e e Q KS kcl h KS e kcl takes a dominant part of energy during cement producing, the uncertainty for E KS is approximated by the uncertainty for e kcl

18 5. Inventory for carbon generated by flue gas in stacks Applying IPCC Tier 3 procedure --- mass balance procedure coal powder is weighed in front of the entrance of furnace calorific value is measured by bomb calorimetry by sampling coal powder in front of the entrance of furnace residual coal in ash is measured mass of ash is measured The uncertainty 2 % to 4 % is anticipated if good metrological procedures are applied. The inventory is traceable to the SI unit Emission factor significantly uncertainty is avoided

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