I-DEV0395: The method of measurement of monitoring parameter Operating Hour of Plant (OH) calculated from operating temperature of reactor based measurement to Ammonia flow to Reactor based measurement

Subject: Deviation due to change in the monitoring approach for operating hour calculation for the project campaign.

AM0034 Methodology requires the project proponent to monitor the parameter Operating Hour (OH) of a Nitric acid Plant during the project campaigns.
As per the registered PDD, OH is required to be monitored as “Recorded at CEM system based on temperature limits of Reactor hours of daily operation of the plant during the project campaign”. However, during the verification activity at RCF HP unit it is observed that the Operating Hour in the CEM is recorded based on the flow of ammonia to the reactor since the implementation of the DeN2O Catalyst.
A brief background about the conditions in the ammonia oxidation reactor during the nitric acid production process at RCF is described below:
During any start up operations, an associate gas is fed to ignite the pilot burner and the temperature of 250ºC is maintained which preheats the catalyst. Once the temperature is stable, the ammonia flow is introduced, since this being an exothermic reaction, the temperature of the reactor shoots up instantaneously. Once the reactor temperature of 860 ºC is reached the plant is considered operational. However if within 10 min of ammonia introduction, the plant is not operational; the time safety lock would cause the plant to trip down leading to a total stoppage of plant operations. The safety lock is installed as a precaution as if the temperature is below 850ºC it may lead to production of ammonium nitrate, which is an explosive material. Thus the time safety lock ensures that there is no delay of more than 10 min for the temperature to reach 860 ºC once ammonia is fed in the reactor.

Similarly when ammonia flow is cut off while taking plant off stream, temperature also drops instantaneously which is much quicker than 10 min as the air is still supplied to the reactor to cool down the system for further inspection.

Thus , the parameter OH for the plant can in principle be monitored by using either of the two independent methods:

1. Based on the temperature limits of the reactor as described in the PDD.
The plant is considered operational only when the temperature of the ammonia reactor is ≥860ºC. The temperature measurement is at the interval of every 2 seconds.
2. Based on the introduction of ammonia flow to the reactor.
The plant is considered operational during times the ammonia flow is introduced in the pre-heated reactor.

The time gap comparison between the two methods demonstrates marginally difference. The time difference can maximum be for 10 min as per the time safety lock installed in RCF. Therefore both the methods are considered equally good to record operating hours of the plant as the CEM system installed calculates the hourly average based on the data monitored at an interval of every 2 seconds. Further if the plant operation is less than 30 min during any particular hour, the value for that period would not be considered. The difference of the two approaches would have an impact on the operating hour determination only during start-ups or shut downs when the temperature crosses the value of ± 860ºC.
To assess the impact of change, the Operating Hour OH for all the start-ups and shut down observed during second campaign (as the complete campaign is under the crediting period) the period have been considered; the total number of start ups are 8 while a total of 8 shut downs were observed. Considering the maximum of 10 min delay (theoretical maximum) for each start-up we have 80 min of plant operation. If similarly for shut down once the ammonia flow is cut-off the time delay is neglected as a conservative approach, the theoretically maximum effect can be estimated to be 80 mins of operation. The real effect is considered to be much less. Thus both approaches can be considered to be not materially different in the context of this PA. Furthermore it is to be mentioned that the sought deviation should also be applicable for the baseline campaign as OH during the baseline campaign was also based on the introduction of ammonia flow to the reactor.
The impact of the same is a reduction of 12 tCO2e observed for the second campaign (2010-02-13 to 2010-0707 a complete campaign), the impact on other campaign is assessed to be even lower as the monitoring period covers only part campaigns.

However the logic was configured on 2nd method and this remained applicable during 20/11/2009 to 09/07/2010. The same has been switched over to 1st method on 09 July 2010, which is in line with the registered PDD. Thus the deviation is sought for the period of 20/11/2009 – 09/07/2010. The details of the monitoring periods covered under this deviation are as follows:
• First Monitoring period covering the period from: 20/11/2009 to 12/02/2010 (first campaign)
• Second Monitoring period covering the period from: 13/02/2010 to 07/07/2010 (second campaign)
• Third Monitoring period covering the period from: 07/07/2010 to 09/07/2010 (third campaign)

The deviation is temporary in nature and the operating hour recording at RCF HP plant has been shifted to be based on the temperature of the reactor since 9th July 2010. Thus this does not require a revision of monitoring plan or the changes from the project activity as described in the registered PDD.

To assess the impact of change, the Operating Hour OH for all the start-ups and shut down observed during second campaign the period have been considered; the total number of start ups are 8 while a total of 8 shut downs were observed. Considering the (theoretical) maximum of 10 min delay for each start-up we have 80 min of plant operation. If similarly for shut down once the ammonia flow is cut-off the time delay is neglected as a conservative approach, the theoretically maximum effect can be estimated to be 80 mins of operation. The real effect is considered to be much less. Thus both approaches can be considered to be not materially different in the context of this PA.
The impact of the same is a reduction of 12 tCO2e observed for the second campaign (2010-02-13 to 2010-0707 a complete campaign), the impact on other campaign is assessed to be even lower as the monitoring period covers only part campaigns.