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CO 2 : How refineries managed with ETS. IPIECA - Bruxelles 1st march 2011. CO 2 in Europe. Introduction – market rules for ETS Principles CO 2 emissions in refineries pre-existing tools Adaptation of the tools Uncertainty – still in progress. CO 2 in Europe.
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CO2 : How refineries managed with ETS IPIECA - Bruxelles 1st march 2011 IPIECA Bruxelles 1er mars 2011
CO2 in Europe • Introduction – market rules for ETS • Principles • CO2 emissions in refineries pre-existing tools • Adaptation of the tools • Uncertainty – still in progress IPIECA Bruxelles 1er mars 2011
CO2 in Europe • A commercial product since 2005 • It has to be « weighed » in such a manner that the buyer is confident in the quantity he paid for. • European rules are documented in the EU Commission Decision on MRG (Monitoring and reporting guidelines). • How does it work ? • Monitoring plan • Yearly verification IPIECA Bruxelles 1er mars 2011
Regulation IPIECA Bruxelles 1er mars 2011
Method of calculation of CO2 emissions- Principles • Completeness: • The search for sources of emissions of individual atmospheric pollutants must cover all activities on site. • Traceability - transparency: • The assumptions made and the methods used for data reporting must be documented. • Records must be kept in order to ensure the traceability of data for checking. • All documents relating to the process must be accessible for audit. • Consistency: • The atmospheric pollutant emission balances must be based on a set of data consistent with the refinery’s other balance figures. • Accuracy: • Emissions must be calculated, insofar as possible, using methods available providing the best degree of accuracy. • The uncertainty with which the result is expressed must be the subject of a documented and auditable calculation; • Analysis of its components should enable identification of the improvements to be made in order to reduce them and make provision for the corresponding actions when the degree of uncertainty is considered insufficient. IPIECA Bruxelles 1er mars 2011
Calculation of CO2 emissions • Generic expression : • CO2 = • Qi(t) = Flow rate (fuel, flue gas, throughput… ) on which is based calculation of CO2 emission of the source i, at time t • Ci(t)= C content of source i • Complete combustion is assumed (oxidation factor=1) x Flow rate (t/h) CO2 (t/h) C content (%wt) IPIECA Bruxelles 1er mars 2011
Process of CO2 emission CO2 Flares balance Flares Fuel balance Products Furnaces Crude Reaction balance internal Fuels Reactors fuels air, O2, H2O IPIECA Bruxelles 1er mars 2011
CO2 emissions in refineries pre-existing tools • Calculation of the amount of fuel burnt: • Essentially by means of pressure difference flow measurement devices • Designed to manage energy performance in absolute as well as in trend • Production accounting: • Accounting at the refinery fenceline ; reconciliation balance for internal flows • The difference in mass balance at the refinery fenceline represents the sum of losses + fuel consumption • Accounting losses constitutes the reconciliation term IPIECA Bruxelles 1er mars 2011
Fuel balance Losses (flue, walls) ∆Hfuel ∑ in ∑ out Process out ∆Hprocess Produced FG Consumed FG Process in Mass balance ∑ in = ∑ out Enthalpic balance ∆Hfuel = ∆Hprocess + thermal losses IPIECA Bruxelles 1er mars 2011
Fuel balance Raw data Reconciled data f1 F1 fi Fi fn Fn IPIECA Bruxelles 1er mars 2011
Mass balance losses Flue gases flares accounting Fuels Throughput - IN Flares Products - OUT Tanks Mass balance IN = OUT + Delta stock + fuels + losses Losses = physical losses (flares) + balance term IPIECA Bruxelles 1er mars 2011
Usual tool : fuel flow meter • Flow rate measurement by means of a pressure differential device • Qwt CO2 = Qfuel *%Cfuel *44/12 IPIECA Bruxelles 1er mars 2011
Usual tool: FCC • Simplified flow diagram flue N2 Products to fractionation Regenerator Reactor Flue gas %CO2 %O2 %CO %N2 Others… FCC feed catalyst Qair %N2air (based on dry flue gas) • (1) - Mass balance N2: QN2 smoke + QN2 to fractionation+ 1/2 x QNOx = QN2 in • (2) - Qsmoke= • (3) - Qwt CO2 = (%vol CO2 + %vol CO ) * Qsmoke* MWCO2 / 22400 • Soit : Qwt CO2 = f(%vol CO2 , %vol CO , %O2 ,…, Qair , N2effluent) IPIECA Bruxelles 1er mars 2011
How refineries met the requirements • Completeness • No difficulty to meet • Traceability - Transparency • Fuel accounting procedures were not well documented and the accounting itself was poorly traced. • Actions : • Generalization of procedures registered in the documentation system under quality insurance. • Generalization of registering all modifications made to the raw set of data in order to obtain the official set • Consistency • Harmonisation of procedures for material balance • Some difficulties in harmonizing monthly data with later corrections (annual data for CO2 vs monthly data for other purposes) IPIECA Bruxelles 1er mars 2011
Accuracy : Requirements from the European Decision on MRG • Fuels • Definition : fuels are grouped by « source stream », defined as « specific fuel type ». • Flow rate measurement : annual consumption must be calculated with an uncertainty less than 1,5% • C content : • Liquid : analysis has to be performed by a laboratory certified ISO 17025 or equivalent • Gas : the chromatograph must have an initial verification and an annual cross-check. • Frequency of sampling : in the base case, 1/day for Fuel Gas • FCC • CO2 : annual CO2emissions from the FCC must be calculated with an uncertainty less than 2,5% • On-line analyser : same requirement as for the chromatograph, assuming a particular interpretation of the Decision. IPIECA Bruxelles 1er mars 2011
Accuracy : gap analysis • Material balance at the refinery fenceline is not accurate enough for the purpose of ETS : • Accuracy of the overall balance is set by that of the certified meters i.e. 0,3% • The term losses + fuels constitutes approximately 6% of the crude throughput • The reconciliation term may therefore constitute 0,3 / 6 = 5 % of the fuel consumption • Flow measurement of fuels by simple pressure differential devices does not meet the required accuracy level. IPIECA Bruxelles 1er mars 2011
Accuracy : Uncertainty calculation • Principles: • Error propagation law : the simplified rules in the MRG give a good basis for practical use • Measurement uncertainty factors are classified according to their level of correlation into 2 categories: correlated or independant. • Practical adaptation : • Elimination of some over-simplified methods, such as attributing a standard relative uncertainty to measurements obtained by a pressure differential device (see above) • Calculation of the total annual amount of a flow : correlation between parameters in 2-dimensions • Time correlation • Correlation between measurement devices at the same time IPIECA Bruxelles 1er mars 2011
uncertainty calculation : mass flow with pressure differential device Data treatment product conditions conversion temperature SG 15 compression pression viscosity Numerical treatment Mass flow Ambiant conditions diameter sensibilities diameter tappings edge sharpness Zero drift Straight lengths Surface condition Pipe roughness Scale drift ∆P device Measurement of ∆P Pipe Assembling IPIECA Bruxelles 1er mars 2011
C content for fuels • No reference standard • Organization of Round Robin tests inter companies and inter countries • Round Robin tests for Fuel Gas : • According to DIN 51666, in progress for EN homologation • 1 test / year on 2 measurements by each laboratory, on the same sample • A little better than the repeatability and reproducibility of the norm • Beware of the risk of air contamination of the sample • Round Robin tests for Fuel Oil : • According to ASTM D 5291 • No problem IPIECA Bruxelles 1er mars 2011
FCC CO2 emissions • Air flow-rate measurement (Qmasseair) • Industrialdevicebetterthan 1,5% uncertainty? • Pitot : no normavailable • Other : calibration devices for ranges 105 Nm3 /h ? • CO2 concentration in flue gases: • Uncertainty • Uncertainty on instantaneousmeasurement >> 2,5 % • Uncertainty on annualamount of CO2: • Reduced by means of periodicgauging : complexmechanisms • Result: ? IPIECA Bruxelles 1er mars 2011
FCC H2O & N2 to Result N2 SO2 or CO2 Air rate fractionation 3% 3% 2% 0,5% 4,7% FCC CO2 emissions: Uncertainties IPIECA Bruxelles 1er mars 2011
Organisation • CO2calculationsrequire new tools, also changes in the usualrefinery organisation : • Tightening of fuel balances : methodssimilar to legalmetrology • Coordination between services : Maintenance, materialacccounting, environment and mathematicaluncertaintycalculation IPIECA Bruxelles 1er mars 2011
Back-up • Incertitude du débit mesuré par plaque à orifice • Sensibilité de l’incertitude de mesure de débit vs étendue d’échelle • Exemple de feuille de calcul pour la somme de combustibles • RRT FG • Influence de la réconciliation de données sur l’incertitude IPIECA Bruxelles 1er mars 2011
Incertitude sur une mesure de débit par plaque à orifice (1) • La norme ISO 5167-1 donne l’expression de l’incertitude du débit Q : • Les principaux paramètres d’influence sont : • La masse volumique aux conditions de fonctionnement • Le diamètre de la plaque à orifice • Et dans une moindre mesure le coefficient de décharge C • Par ailleurs, la formule représente l’incertitude pour un débit égal à l’échelle de mesure. Le pourcentage du débit mesuré par rapport à l’échelle de l’appareil est un paramètre de premier ordre pour le calcul de l’incertitude IPIECA Bruxelles 1er mars 2011
Incertitude sur une mesure de débit par plaque à orifice (2) • Variation de l’incertitude pour 2 couples de valeurs d’incertitudes sur le diamètre de la plaque à orifice et du transmetteur de delta P et en fonction des incertitudes sur la masse volumique et du pourcentagede la mesure par rapport à l’échelle de mesure. IPIECA Bruxelles 1er mars 2011
Calcul d’incertitude IPIECA Bruxelles 1er mars 2011
RRT for FG IPIECA Bruxelles 1er mars 2011
Incidence de la réconciliation du bilan combustible • Réconciliation de données: • Améliore la précision du bilan brut issu des systèmes de mesurage • Agit selon 2 mécanismes : • Correction d’erreurs • détection des mesures de débit défaillantes. • substituer une valeur vraisemblable • Réduction de l’incertitude proprement dite • Prise en compte de mesures de débit redondantes • Algorithme de minimisation des erreurs • Prise en compte: • Réseau de combustibles avec n producteurs et p consommateurs • Facteur de réduction de l’incertitude (dans un cas simple): IPIECA Bruxelles 1er mars 2011