16:50 20 May 19
I-DEV0273: Location of the Tflare probe and measure of total amount of landfill gas captured LFGTOTAL,y
|Submitted by||TÜV SÜD (27 Nov 2009)|
|Project activity||1258: Quezon City Controlled Disposal Facility Biogas Emission Reduction Project|
|Selected monitoring period||01 Sep 2008 - 30 Jun 2009|
|Title/subject of deviation||Location of the Tflare probe and measure of total amount of landfill gas captured LFGTOTAL,y|
Tflare is supposed to be a measure of temperature in the exhaust gas of the enclosed flare as per the “Tool to determine project emissions from flaring gases containing methane” and as per the registered PDD; however in practice the flare combustion temperature has been monitored with a probe located just above the burner (see position n.5 of the attached drawing BTG2500HTT150). For structural reasons in order to guarantee 100% of flare efficiency the mixture of air and gas is changing on the basis of the flare temperature measured in the actual position, hence there was a misinterpretation about the correct location of the measurement point.
A similar deviation was submitted during the 1st verification (first monitoring period 01-02- 2008 to 31-08-2008) and was accepted by EB 45, 11-13 February 2009. Subsequently on 9th November, 2008, an additional Tflare probe (TT05) has been installed at the same level of the existing oxygen and methane fraction probes to be in line with both the applied methodology and tool. Therefore during the current monitoring period (2nd verification), a deviation is being requested from 1st September 2008 to 8th November 2008.
LFGTOTAL,y in main line should be monitored as per ACM001, version 5 and the registered PDD. However the turbine flow meter measuring this parameter suffered a breakdown due to which an alternative method was used that resulted in deviation. The breakdown was due to mechanical wear and tear and corrosion caused by a combination of high exit temperatures at the blower and the location of the meter on the horizontal length of the main line resulting in prolonged exposure to condensate. To obtain LFGTOTAL,y following alternative method, the SCADA system was automated to calculate LFGTOTAL,y by summation of measured values for LFGflare,y and LFGelectricity,y. In addition the desired conservativeness check of comparing measured and calculated values for LFG TOTAL,y that could enable taking the lower value for emission reduction computation could not be carried out. On the other hand, screenshots of realtime readings from 2 spare annubar flow meters measuring biogas flow rate on line A and line B which merge ahead to form the main line serve as an indicator of how minimum is the variation in calculated and measured LFGTOTAL,y.
A request for deviation from the registered PDD is therefore submitted according to the fact that two spare Annubar-type flow meters have been in place for the whole monitoring period, measuring biogas flow rate on line A and line B that merge ahead to form the main line. It’s therefore requested to deviate from the PDD considering the use of these two Annubar meters instead.
A similar deviation was submitted during the 1st verification and was accepted by EB 45, 11-13 February 2009. Subsequently on 27th March 2009 a new flow meter FT03_a has been installed in pace of broken turbine meter to measure LFGTOTAL,y correcting the deviation. Therefore during the current monitoring period (2nd verification), a deviation is being requested from 1st September 2008 to 26th March 2009.
The project activity has deviated from the registered PDD since:
The Tflare probe has been installed inside the enclosed flare at a height of 1.8 meters above the burner which doesn’t actually measure the “Temperature in the exhaust gas of the flare” (as defined in the “Tool to determine project emissions from flaring gases containing methane”).
This deviation from the Methodological Tool has been confirmed by the DOE during site audit on 23rd and 24th September 2009, and it can be confirmed that it will be addressed and resolved by the PP’s by installing a second Tflare probe at the correct height of the flare; such probe, which will be placed at the same level of the oxygen and methane fraction probes, will allow to fully comply with the methodology. According to this, no amendment of the Methodology is required.
The LFGTOTAL,y parameter has been measured by PP’s using two additional Annubar-type meters on lines A and B instead of a single turbine meter on the main line, as defined in the registered PDD.
As confirmed by the DOE during site audit on 23rd and 24th September 2009, this deviation in the LFGTOTAL,y measurement approach has been applied by the project participants due to the breakdown of the main turbine meter. The redundancy of the measurement equipments whichwas in place has allowed the PP’s to use the two Annubar meters to estimate the LFGTOTAL,yand to compare it with the sum of the flow data LFGflare,y and LFGelectricity,y. The results obtained confirm that this approach, due to the accuracy of the Annubar meters, allow to perform the required verification (i.e. LFGTOTAL,y = LFGflare,y + LFGelectricity,y) in a reliable way. A deviation is therefore necessary due to this breakdown event and it is confirmed that this is a project-specific situation. Thus, an amendment of the applied Methodology is not required.
The actual location of the measurement point of the Tflare has no impact on the estimation of the Emission Reductions. In fact, the calculation tool doesn’t include Tflare in its calculation formula. Tflare is only used as a reference value i.e. : under 500°C the flare efficiency is automatically considered equal to zero. The only parameters considered in the flare efficiency calculation are the “Volumetric fraction of O2 in the exhaust gas of flare” and the “Concentration of methane in the exhaust gas of flare”. In the case the flare had not worked properly and efficiently due to inadequate capacity or operation, the direct consequence would have been an amount of methane in the exhaust gas greater than zero. In the actual situation this is not the case, because the flare was correctly designed for a maximum flow of 2500 Nm3/h and a minimum flow of 500 Nm3/h and the concentration of methane in the exhaust gas can be greater than zero only for few minutes in the transitory conditions during shut down or start up. Furthermore, according to the operating manual of the flare, the Tflare (measured at the actual point, above the burner) should range between 850°C to 1250°C to ensure an optimal and proper operation of the flare. The Tflare data collected during this monitoring period falls within the manufacturer’s specification, further demonstrating that the flare has been properly installed and operated. According to these considerations this deviation cannot have impact on the ER’s estimation.
The deviation to measure the LFGTOTAL,y using the two Annubar-type meters instead of the turbine meter aswell has no impact on the estimation of the Emission Reductions. Two Annubar flowmeters have been installed in Line A and line B. These two lines combine ahead to form the "main line" which later divides into flare line and engine line; LFGTOTAL,y is measured considering the sum of Annubar instruments instead of the broken flow (turbine) meter. The instruments are correctly identified and calibrated periodically and the precision is higher than the turbine flow meter (Annubar error 0.075% - turbine meter error 0.25%). Even if SCADA system has not been registering the readings of the annubar flowmeter, anyway it has been verified on site through real time readings that the data are consistent. According to these considerations this deviation cannot have impact on the ER’s estimation.
|Annexes||Enclosure (78 KB)|
|Enclosure 1 (228 KB)|
|Link to the documentation made available at validation stage or monitoring report||Link to relevant documentation|
|Signed form||Signed form (745 KB)|
|Decision||This request for deviation has been accepted.|
|Current status||08 Feb 2010 - Deviation accepted|
27 Nov 2009 -
31 Dec 2009 - Successfully passed the Completeness Check
22 Jan 2010 - Awaiting EB decision