Custody transfer of NG in Korea

Transcription

1 Custody transfer of NG in Korea NG Production Import / Storage Metering Station Major Customer End user LNG Supplier LNG Carrier Pressure regulating Power Plant Liquefaction Plant Receiving Terminal City Gas Company Commercial / Industrial User Residential User LNG Ship CTMS KOGAS Metering Station Transportation Fuel

2 Custody transfer flowmeter of City Gas Company City Gas Company Commercial / Industrial User Diaphragm gas meter Turbine gas meter Rotary gas meter Residential User Diaphragm gas meter Transportation Fuel Coriolis gas meter

3 Custody transfer flowmeter for residential users G.6 : (0.06~2.5) m 3 /h G2.5 : (0.025~4.0) m 3 /h G4 : (0.04~6.0) m 3 /h Diaphragm gas meter was installed and used depending on the quantity consumed of residential users such as households, apartments and etc.

4 International Recommendation of gas meter Accuracy Classes and Maximum Permissible Errors (MPE) Flowrate Q During type evaluation and initial verification Accuracy Class During subsequent verification and In service Accuracy Class Q min Q < Q t ± % ± 2 % ± 3 % Q t Q Q max ± 0.5 % ± % Q 3 log( Q max min ) ±.5 % Test flow rate for Type evaluation test N ± 2 % ± % ± 4 % ± 6 % ± 2 % ± 3 % Based on three test points per decade the minimum number(n) of test points

5 Type approval and Verification Type approval Initial Verification 5year Subsequent Verification Type evaluation test Courtesy : KTC - Error, Reproducibility, Repeatability, Working pressure, Durability, etc. Verification Test - Accuracy test, Adjustment, Time interval( 5 year for Q max <0 m 3 /h, 8 year)

6 Verification Test System Courtesy : KTC

7 Verification Test System Sonic Nozzle Wet gas meter Courtesy : KTC

8 KRISS Low Pressure Gas Flow Standard Bell Prover Piston Prover Standard Flow Capacity Uncertainty Bell Prover L/min 0.% Piston Prover L/min 0.3%

9 Volume Correction of NG during transaction City Gas Company Residential User NG Transaction Reference condition : 0 C, kpa Diaphragm gas meter NG Transaction Reference condition : Actual condition Gas temperature and pressure of actual gas flow are quite different from the reference conditions. Volume correctors are used to calculate gas volume at the reference conditions in the industrial and commercial gas flow meters.

10 Volume Correction Factor t: Period of volume correction q: Gasflowrate T gas : Gas temperature( ) P gas : Gas pressure(mbar), P atm : Atmosphere pressure(mbar) Compressibility factor at measuring conditions is assumed similar to that at reference conditions due to small differences of gas pressure and temperature Volume correction factor is higher than in the winter and lower than in the summer. To reduce complaint of billing, one year was chosen as the best period in Korea.

11 Volume Correction Factor Gas billing = Gas meter volume * K * CV(MJ/m 3 ) 42 area s volume correction factor were calculated. Ten year average value from last year is used for this year

12 Custody transfer flowmeter of Transportation City Gas Company Commercial / Industrial User Diaphragm gas meter Turbine gas meter Rotary gas meter Residential User Diaphragm gas meter Transportation Fuel Coriolis gas meter

13 CNG Station in Korea City Gas Line (4 bar) Flowmeter Compressor (250bar) Control panel Storage tank Dispenser(200bar) Rotary gas meter Turbine gas meter Courtesy : Samchully Gas

14 CNG Dispenser Coriolis flowmeter is installed in CNG dispenser. Volume correction factor and average calorific value are used to calculate total transaction rate Korea Government is enacting laws on CNG dispenser including flowmeter.

15 Custody transfer for CNG dispenser Water calibration of flowmeter Courtesy : Emerson

16 Custody transfer for CNG dispenser Portable CNG Field Proving meter Courtesy : Emerson

17 Custody transfer of NG in Korea NG Production Import / Storage Metering Station Major Customer End user LNG Supplier LNG Carrier Pressure regulating Power Plant Liquefaction Plant Receiving Terminal City Gas Company Commercial / Industrial User Residential User LNG Ship CTMS KOGAS Metering Station Transportation Fuel Legal metrology

18 Thank you for your kind attention!