I-DEV0425: 1. Monitoring the Stack gas flow rate on a daily basis instead of continous basis. 2. Deviation from direct monitoring of biogas to boiler (as recommended (FAR#1) by the DOE through 3rd verification report dated 05/05/2009)

The project activity is the implementation of a closed anaerobic system (digesters) to treat the paper mill effluent (Bagasse Wash Water) that was earlier being treated in open anaerobic lagoons. The biogas generated is combusted in a lime kiln (heating equipment) where the temperature is maintained around 1150ºC. During limekiln shutdown, the biogas could be used in the power boiler (if needed). The same is considered to be flared.
This deviation request is applied for the following two issues.

Deviation 1:
As per the applied methodology, AM0013 Version 02, stack gas CH4 emissions are considered as a minor / negligible source of project emissions that need to be monitored. The methodology states “There are several other minor sources of project emissions associated with fossil fuel use (if any), fugitive CH4, and stack gas CH4. These do not need to be estimated ex ante, unless it is known that a large amount of fossil fuel is to be used as supplementary fuel. After project implementation, these emissions will be monitored. If the emissions from an emission source are greater than 1% of the annual total CERs, they will be included as project emissions.” “As per the accompanying baseline methodology, each of the three minor emission sources (emissions associated with fossil fuel use, fugitive CH4, and stack gas CH4) is considered to be negligible.”

For this project activity, the emissions from stack gas CH4 are calculated as follows:
Emissions from stack gas CH4 = Stack gas CH4 content X Stack gas flow rate X 21 (GWP of CH4)
Where,
Stack gas CH4 content is monitored twice a month for this monitoring period. This is in accordance with the registered monitoring plan (where the monitoring frequency is “At least quarterly”).
Stack gas flow rate is required to be monitored on a continuous basis as per the registered monitoring plan (ID number D.3-11 in the PDD). Additionally, the constraints in the installation of continuous flow meter have been described in the registered PDD monitoring section D.2.1 (page 32) which states “The biogas is used in the kiln where nearly 1150ºC is maintained. Theoretically all the CH4 will be destroyed. However efforts are on to explore the possibility of installing a flow meter”.

The deviation is sought for the daily monitoring (For the period January 01, 2008 to May 28, 2010) compared to continuous monitoring of stack gas flow rate. The deviation is only for the current monitoring period and does not necessitates any further subsequent deviation request. Since, the flow meter has been installed on May 29, 2010 to continuously monitor the stack gas flow rate.

Continuous monitoring of stack gas flow:
The continuous monitoring of stack gas flow rate using flow meter is primarily dependent on the stack gas properties. In case of project activity, the stack gas from PP’s lime kiln is at a very high temperature and consists of high Suspended Particulate Matter (SPM) concentration and other corrosive elements. Therefore, it is difficult to continuously monitor the stack gas flow rate using flow meter, specifically for the project activity considering the stack gas properties. Additionally, it could be noted that theoretically methane would be destroyed completely at a very high temperature of 1150oC. The same has been indicated in the registered PDD monitoring section D.2.1 (page 32) which states “The biogas is used in the kiln where nearly 1150ºC is maintained. Theoretically all the CH4 will be destroyed. However, efforts are on to explore the possibility of installing a flow meter”. The same is inferred from the stack gas methane content analysis reports for the monitoring period .

The stack gas flow rate was monitored (i.e. 1st January, 2008 to 28th May, 2010) on a daily basis using a Pitot tube. The velocity of the stack gas (in meters/second) measured on a daily basis (by the Pitot tube) is multiplied with the stack flow area (in Square meters) to arrive at the daily stack gas flow, which has been recorded.

Daily stack gas flow rate (M3/s) = Velocity of stack gas (in M/s) X Stack flow area (in M2)
The stack gas flow thus arrived has been recorded on a daily basis and archived.

Efforts made by PP for installation of stack gas flow meter:
The Project Participants (PP) has approached several reputed equipment suppliers for installing a continuous flow meter for the above application . Due to sustained efforts of PP, a reputed equipment supplier was identified and the stack gas flow meter was installed, subsequently on May 29, 2010.

Following are the steps followed in the procurement of flow meter from the equipment supplier,

In case of M/s Tamil Nadu Newsprint & Papers limited established by Govt. of Tamil Nadu, India, the purchase of equipment undergoes following procedures .
A note on the monitoring system for biogas CDM project stating the overall CDM monitoring requirements was submitted to management for their approval on November 19, 2008. Post approval from the management, the proposal was included in the capital budget 2008-09. Subsequent to the allocation of capital budget, electrical and instrumentation department issues the “user indent” application to Purchase team indicating various details like type, quantity, cost of equipments, etc…The same was provided through the letter dated January 13, 2009. Upon receipt of request from instrumentation department a recommendation for extended enquiry (i.e. enquiry would be sent to various vendors) would be placed by the Purchase department. The extended enquiry was sent on February 9, 2009. Post receipt of letter for intent from the equipment suppliers and techno-commercial discussion, an approval note would be generated by the Purchase team. The same was provided on June 16, 2009. In this approval note out of five suppliers approached PP only one supplier has responded. Based on the approval note for purchase of an equipment, a purchase order would be placed against the selected entity. Accordingly, the purchase order was placed on M/s Chemtrols Industries Ltd. on June 30, 2009. With the constant follow up with equipment supplier (e-mail dated 29/09/2009) for urgent supply of the equipment, the flow meter was dispatched on December 31, 2009 by the equipment supplier. The flow meter supplied M/s Chemtrols Industries ltd. was commissioned by the supplier on May 29, 2010 .

Deviation 2:
Biogas generated in the digester is predominantly used in the heating equipment (i.e. lime kiln). During the lime kiln shut down, there is a provision to use the biogas in the power boiler, if required. Alternatively, the biogas could be flared. The biogas used in the boiler, if any, is also considered to be flared. The same is not considered for emission reduction calculations.

During third verification, a Forward Action Request (FAR#1) was raised by DOE to include the monitoring of the biogas going to power boiler and with the inclusion of this parameter (biogas sent to boiler) a revised monitoring plan was recommended before the next request for issuance through the verification report dated 5th May 2009. Accordingly, a request for revision in monitoring plan is being applied separately for the same. However for the period 1st January 2008 to 31st October 2009 the flow of biogas to boiler is monitored using the flow rate monitored in the biogas flow meter at digester outlet and the time period of flow. Hence deviation is requested. The dedicated flow meter to monitor the biogas flow to the boiler has been installed on 1st November 2009.

Provisions of registered Monitoring Plan:
During limekiln shutdown, the biogas generated is sent to the power boiler for flaring, as indicated in the registered PDD. Refer page 7/64“During lime kiln shut down the biogas is used in power boiler. The gas handling system is also provided with flaring system to flare the biogas when it is not used in kiln or power boiler”.

Biogas flow to boiler - Monitoring Procedure:
Prior to the installation of dedicated biogas flow meter for the boiler, the monitoring procedure are as follows:
During limekiln shutdown, the biogas plant operator would be informed about the shutdown of heating equipment and alternate action plan for usage of biogas would be planned ((i.e.) either it could be used in boiler or flared). In case of any usage of biogas in the boiler, the biogas flow rate from the digester outlet flow meter along with the time period of flow to boiler would be used to monitor the biogas supplied to the boiler (example: On 21st January, 2008, the biogas was sent to boiler at the rate of 400 m3/hr, based on the instantaneous reading of biogas flow at digester outlet, for the time period of one and half hours. Therefore, a total of 600 m3 of biogas has been considered as biogas supplied to the boiler). Since the biogas supplied was considered as flared there is no impact on the emission reduction calculation.

Based on the Forward Action Request raised by the DOE through their verification report dated May 05, 2009, PP has installed a dedicated continuous flow meter for continuous measurement of biogas flow to boiler . The same was installed on November 01, 2009. Post installation of flow meter, the flow meter has been interfaced with DCS system and the values are recorded at least once in a shift.

Deviation Request 1:
The deviation is sought for the daily monitoring (For the period January 01, 2008 to May 28, 2010) compared to continuous monitoring of stack gas flow rate. The stack gas flow meter has been installed on May 29, 2010 to continuously monitor the stack gas flow rate. Therefore, the deviation doesn’t require a revision of monitoring plan or the changes from the project activity as described in the registered project design document.

Deviation Request 2:
The PP has already installed the dedicated flow meter on 1st November 2009 to monitor the biogas flow to the boiler. Revision in monitoring plan has been applied to include the continuous monitoring of the biogas to the power boiler. Deviation has been applied for the period 01/01/2008 to 31/10/2009.

Deviation Request 1:
As indicated in the approved methodology and stated in the registered PDD , stack gas CH4 emissions are a negligible source of emissions as all the methane will be destroyed at the kiln temperatures of around 1150 °C. This is observed from the monthly stack gas chromatography analysis reports which indicate the stack gas CH4 content as zero. As a result the project emissions from the stack gas would be zero irrespective of the stack gas flow rate. Thus, any impact of the deviation on the stack gas flow rate would not alter the emission reductions.

Deviation Request 2:
For the period 01/01/2008 to 31/10/2009, biogas has been predominantly used in the heating equipment only. However, any usage in the boiler (i.e .3,300 M3 for the period 01st January 2008 to 31st October 2009) is considered as flared. Thus, any impact of the deviation on the biogas flow rate to the boiler would not alter the emission reductions.