The looking to improve accuracy and ease of operation, in a historically challenging gas measurement application.
In Canada the implementation of Enhanced Production Audit Program (EPAP) will increase the need for more accurate flow measurement data.
Technical Challenge
Energy producers are constantly looking at ways to improve their standard natural gas measurement points within their operations. One critical area that requires consistent and reliable measurement is fuel gas meters typically located at compressor sites. On larger compressors or sites with multiple compressors where daily average consumption exceeds 0.5 em/day ERCB Directive 17 stipulates that a permanent measurement device must be installed for all fuel gas consumption.
A Case study: 2 large energy producers with part of their operations in Northwestern Alberta and Northeastern B.C. were faced with finding and standardizing on a solution that would meet the challenges posed by measuring fuel gas accurately and consistently in a reliable and economic package that would also meet Directive 17 compliance. The importance is being underscored with the full scale implementation of EPAP (Enhanced Production Audit Program) in 2011 industry wide.
Traditional means of measuring fuel gas fell short of their goals in meeting this standard. Orifice plates lacked the turndown range required to measure both the nominal fuel gas consumption and the start gas when a compressor is activated. The companies preferred a device that could handle both measurements seamlessly. Additionally, the lower flow ranges typically found on a fuel gas line posed a problem due to an orifice plate's high pressure drop and accuracy was compromised as a result.
While a standard pressure and temperature coefficient can be applied to complete the flow measurement rate, this introduced a manual process by which the operators/supervisors had to adhere to for completion of their calculations. In addition, PD meters were susceptible to damage due to over ranging when a compressor was started resulting in costly maintenance and downtime. A solution was needed.
The Flowstar Solution
Both companies found their solution in a gas measurement system consisting of a high accuracy, robust gas turbine in concert with an electronic flow computer (EFM).
The gas turbine provides excellent accuracy profiles (+/- 2%) in a 316 stainless steel constructed body and internal components that utilize ceramic, self lubricating, low drag bearings. A 40:1 turndown ratio ensures that both the nominal fuel gas and the compressor start gas are accurately measured. As fuel gas lines are typically smaller in design (1") the low flows seen are easily measured by a 1" turbine. Flexibility is built into the turbines as the rotor pitch can be changed to as low as 45 degrees to capture even lower flows at similar pressures. The standard pitch is 15 degrees.
The Hawk 9500 EFM delivers exceptional operational performance with a rated accuracy of +/- 0.05% full scale on pressure and +/- 0.5% C on temperature. The Hawk 9500 performs fully compensated flow rate calculations to AGA7 (rotary turbines) and AGA8-92 (gas compressibility) standards. It is also API Chapter 21 audit trail compliant. With its Class I Div I IS rating and IS lithium ion battery pack, area classifications are not an issue and offer the end user ease of installation and smaller footprint. A communication board can be activated to support RS 485 Modbus communications to a SCADA host or PLC.
Results
Both energy companies have implemented the Flowstar gas measurement solution on a number of compressors with excellent results to date. With this arrangement it minimized operator involvement and interruptions and also provided them with a 1 stop service point for any future technical adjustments or troubleshooting. When producing a trending graph of historical data on one particular 1" line it produced a flow rate of 0.5 em/day at 110 psi. The peak volume on compressor start up, however, reached as high as 14 em/day, representing a turndown ratio of 28:1, well within the range.
In certain cases, as with the other energy producers, a mechanical pipe run with the gas turbine was provided without the Hawk9500 at certain locations as an existing RTU was already on site. The introduction of a pre-amplifier easily supported this type of integration. Their operators have commented positively on the overall reliability of the gas turbine and the relatively small footprint of the meter run piping package. Process conditions are favourable on the fuel gas line as the meter is typically installed downstream of a fuel gas scrubber. The operators also like the convenience of noting instantaneous data on the Hawk 9500 display (current flow rate, pressure and temperature and up to 40 previous days of historical production) and the ability to download stored data onto the SD card (over 1 year with 1 minute logging). This data is easily transformed into production reports that are provided to the companies' production accountants electronically.
EPAP will help guide the producers to measure gas more accurately and there are only a few options available to ensure accuracy with ease of use out in the field.
SIGIT Products
Article Source: http://EzineArticles.com/?expert=Sean_A_Sandhurst
In Canada the implementation of Enhanced Production Audit Program (EPAP) will increase the need for more accurate flow measurement data.
Technical Challenge
Energy producers are constantly looking at ways to improve their standard natural gas measurement points within their operations. One critical area that requires consistent and reliable measurement is fuel gas meters typically located at compressor sites. On larger compressors or sites with multiple compressors where daily average consumption exceeds 0.5 em/day ERCB Directive 17 stipulates that a permanent measurement device must be installed for all fuel gas consumption.
A Case study: 2 large energy producers with part of their operations in Northwestern Alberta and Northeastern B.C. were faced with finding and standardizing on a solution that would meet the challenges posed by measuring fuel gas accurately and consistently in a reliable and economic package that would also meet Directive 17 compliance. The importance is being underscored with the full scale implementation of EPAP (Enhanced Production Audit Program) in 2011 industry wide.
Traditional means of measuring fuel gas fell short of their goals in meeting this standard. Orifice plates lacked the turndown range required to measure both the nominal fuel gas consumption and the start gas when a compressor is activated. The companies preferred a device that could handle both measurements seamlessly. Additionally, the lower flow ranges typically found on a fuel gas line posed a problem due to an orifice plate's high pressure drop and accuracy was compromised as a result.
While a standard pressure and temperature coefficient can be applied to complete the flow measurement rate, this introduced a manual process by which the operators/supervisors had to adhere to for completion of their calculations. In addition, PD meters were susceptible to damage due to over ranging when a compressor was started resulting in costly maintenance and downtime. A solution was needed.
The Flowstar Solution
Both companies found their solution in a gas measurement system consisting of a high accuracy, robust gas turbine in concert with an electronic flow computer (EFM).
The gas turbine provides excellent accuracy profiles (+/- 2%) in a 316 stainless steel constructed body and internal components that utilize ceramic, self lubricating, low drag bearings. A 40:1 turndown ratio ensures that both the nominal fuel gas and the compressor start gas are accurately measured. As fuel gas lines are typically smaller in design (1") the low flows seen are easily measured by a 1" turbine. Flexibility is built into the turbines as the rotor pitch can be changed to as low as 45 degrees to capture even lower flows at similar pressures. The standard pitch is 15 degrees.
The Hawk 9500 EFM delivers exceptional operational performance with a rated accuracy of +/- 0.05% full scale on pressure and +/- 0.5% C on temperature. The Hawk 9500 performs fully compensated flow rate calculations to AGA7 (rotary turbines) and AGA8-92 (gas compressibility) standards. It is also API Chapter 21 audit trail compliant. With its Class I Div I IS rating and IS lithium ion battery pack, area classifications are not an issue and offer the end user ease of installation and smaller footprint. A communication board can be activated to support RS 485 Modbus communications to a SCADA host or PLC.
Results
Both energy companies have implemented the Flowstar gas measurement solution on a number of compressors with excellent results to date. With this arrangement it minimized operator involvement and interruptions and also provided them with a 1 stop service point for any future technical adjustments or troubleshooting. When producing a trending graph of historical data on one particular 1" line it produced a flow rate of 0.5 em/day at 110 psi. The peak volume on compressor start up, however, reached as high as 14 em/day, representing a turndown ratio of 28:1, well within the range.
In certain cases, as with the other energy producers, a mechanical pipe run with the gas turbine was provided without the Hawk9500 at certain locations as an existing RTU was already on site. The introduction of a pre-amplifier easily supported this type of integration. Their operators have commented positively on the overall reliability of the gas turbine and the relatively small footprint of the meter run piping package. Process conditions are favourable on the fuel gas line as the meter is typically installed downstream of a fuel gas scrubber. The operators also like the convenience of noting instantaneous data on the Hawk 9500 display (current flow rate, pressure and temperature and up to 40 previous days of historical production) and the ability to download stored data onto the SD card (over 1 year with 1 minute logging). This data is easily transformed into production reports that are provided to the companies' production accountants electronically.
EPAP will help guide the producers to measure gas more accurately and there are only a few options available to ensure accuracy with ease of use out in the field.
SIGIT Products
Article Source: http://EzineArticles.com/?expert=Sean_A_Sandhurst
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