Evaluating a tunable filter spectrometer online gas analyzer Juan Escobar, measurement specialist, Saudi Arabian Oil Company (Aramco) May 2015 © Copyright 2015, Saudi Aramco. All rights reserved.

Contents Introduction Relevance of composition in Measurement Alternative Technologies Tunable Filter Spectroscopy Analyzer Testing Results

Saudi Aramco Gas Pipelines Network

Over 120 customers Kingdom-wide FEEDSTOCK AND FUEL Refineries Power Plants Petrochemicals Mining Large and Small scale industry

Volumetric Flow Rate gas equation AGA 3 Orifice calculation factor Reynolds number Fluid velocity Density is heavily depending on composition (AGA 8)

Compressibility is heavily depending on composition (AGA 8) Slope factor Real gas relative density factor Real gas relative density Molecular weight Supercompressibility factor Compressibility is heavily depending on composition (AGA 8)

GC is the incumbent methodology PROS Very well-known technology. Gas Chromatography has been the reference technique since late 1970s Heating value (BTU) & Wobbe Index for energy content Hydrocarbons C1 through C9+, COx, NOx, H2S, Diatomics CONS Long response time. Requires the physical separation of molecules in the samples which takes long. Carrier gas requirement (He, Ar, H2, N2) and safety considerations Relative method with calibration gases Complicated and costly operations and maintenance Bulky and requires a lot of space

GC Alternatives over the years Mass Spectroscopy GC-MS FTIR (optical vibrational, absorption) Raman (optical vibrational, emission) NIR/FT-NIR (optical vibrational, emission) TDL (tunable diode laser) QCL (quantum cascade laser) Now enters TFS (tunable filter spectroscopy)

Tunable Filter Spectroscopy PROS Near real-time gas composition response time with fast updated results. Easy installation with less space requirements. Field mounted, robust and rugged; suitable for harsh industrial environments and hazardous area installation. Minimal maintenance with no consumables. No requirement of carrier gases or calibration gases. CONS New technology. No direct measurement of the diatomic homonuclear components such as H2 (hydrogen), O2 (oxygen) and N2 (nitrogen). www.precisive-instruments.com

Operational Principle Chemometrics Example Configuration Ch. # Compound Range Accuracy 1 Methane 0 - 100% +/- 0.2% 2 Ethane 0 – 25% 3 Propane 4 iso-Butane 0 – 10% +/- 0.1% 5 n-Butane 6 Propylene 7 Ethylene Speciated and Quantified Compounds www.precisive-instruments.com

www.precisive-instruments.com

Lab trial - Natural Gas Mixtures   TFS Ref Error CH4 81.23 81.301 0.071 C2H6 2.80 2.833 0.033 C3H8 0.34 0.391 0.051 iC4H10 0.00 0.064 nC4H10 0.14 0.073 -0.067 C5 0.02 0.043 0.023 N2 14.50 14.19 -0.31 CO2 1.02 1 -0.02 C6 N/A CV (Superior, Gross) 34.901 35.09 0.1881 Wobbe Index 43.486 43.7 0.2131   TFS Ref Error CH4 81.78 81.864 0.084 C2H6 3.07 3.08 0.01 C3H8 0.44 0.482 0.042 iC4H10 0.03 0.077 0.047 nC4H10 0.16 0.095 -0.065 C5 0.00 0.055 N2 12.30 12.015 -0.285 CO2 2.23 2.209 -0.021 C6 N/A CV (Superior, Gross) 35.393 35.68 0.2869 Wobbe Index 43.922 44.23 0.3077   TFS Ref Error CH4 87.68 87.505 -0.175 C2H6 7.54 7.539 -0.001 C3H8 1.65 1.721 0.071 iC4H10 0.25 0.17 -0.08 nC4H10 0.19 -0.06 C5 0.02 0.049 0.029 N2 0.80 0.939 0.139 CO2 1.86 1.848 -0.012 C6 N/A 0.03 CV (Superior, Gross) 42.506 42.45 -0.0565 Wobbe Index 53.262 53.17 -0.0924

Lab trial - Synthetic Mixtures   TFS Ref Error CH4 86.29 86.183 -0.107 C2H6 8.47 8.542 0.072 C3H8 1.84 1.963 0.123 iC4H10 0.31 0.227 -0.083 nC4H10 0.48 0.422 -0.058 C5 0.02 -0.02 N2 1.10 1.12 CO2 1.55 1.543 -0.007 C6 CV (Superior, Gross) 43.163 43.107 -0.0568 Wobbe Index 53.712 53.676 -0.0368   TFS Ref Error CH4 83.37 83.284 -0.086 C2H6 3.07 3.056 -0.014 C3H8 0.40 0.46 0.06 iC4H10 0.10 0.073 -0.027 nC4H10 0.11 0.093 -0.017 C5 0.00 N2 11.23 11.344 0.114 CO2 1.72 1.69 -0.03 C6 CV (Superior, Gross) 35.975 -0.0002 Wobbe Index 44.972 44.971 -0.0018   TFS Ref Error CH4 82.10 82.091 -0.009 C2H6 3.88 3.893 0.013 C3H8 0.88 0.949 0.069 iC4H10 0.18 0.146 -0.034 nC4H10 0.17 0.148 -0.022 C5 0.00 N2 9.80 9.793 -0.007 CO2 3.01 2.979 -0.031 C6 CV (Superior, Gross) 36.731 36.742 0.0106 Wobbe Index 45.310 45.336 0.0257

Field trial – Natural Gas Mixtures   TFS Ref Error CH4 88.878 88.492 0.386 C2H6 8.348 8.2506 0.097 C3H8 0.410 0.5854 -0.175 N2 2.268 1.7188 0.549   TFS Ref Error CH4 89.338 88.587 0.751 C2H6 8.037 8.1416 -0.105 C3H8 0.273 0.4544 -0.181 N2 2.258 1.7114 0.547   TFS Ref Error CH4 89.963 89.037 0.926 C2H6 7.402 7.6049 -0.203 C3H8 0.167 0.3566 -0.190 N2 2.382 1.7509 0.631 Errors obtained when the equipment is tested in a field environment are bigger than the ones obtained at a lab environment.   It is planned to perform another trial with an extended composition, C1-C6+ which is normally used for custody applications, and throughout the year to assess the impact of different seasons on instrument performance.

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