evaluating a tunable filter spectrometer online gas analyzer · saudi aramco: public • very...

Saudi Aramco: Public

Evaluating a tunable filterspectrometer online

gas analyzer

Juan Escobar, measurement specialist, Saudi Arabian Oil Company (Aramco)May 2015

© Copyright 2015, Saudi Aramco. All rights reserved.


Contents

Analyzer Testing Results

Tunable Filter Spectroscopy

Introduction

Relevance of composition in Measurement

Alternative Technologies


Saudi Aramco Gas Pipelines Network


Over 120 customers Kingdom-wide

Large and Small scale industry

Mining

Petrochemicals

Power Plants

Refineries


Volumetric Flow Rate gas equation

Density is heavily depending on composition (AGA 8)

Orifice calculation factor

Reynolds number

Fluid velocity


Compressibility is heavily depending on composition (AGA 8)

Slope factor

Real gas relative density factor

Real gas relative density

Molecular weight

Supercompressibility factor


• 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

GC is the incumbent methodology

• 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

• 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.

• 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

Ch. # Compound Range Accuracy

1 Methane 0 - 100% +/- 0.2%

2 Ethane 0 – 25% +/- 0.2%

3 Propane 0 – 25% +/- 0.2%

4 iso-Butane 0 – 10% +/- 0.1%

5 n-Butane 0 – 10% +/- 0.1%

6 Propylene 0 – 10% +/- 0.2%

7 Ethylene 0 – 10% +/- 0.2%

Example Configuration

Speciated and Quantified Compounds

Chemometrics

www.precisive-instruments.com

Saudi Aramco: Publicwww.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 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 0.043

CV(Superior,Gross) 34.901 35.09 0.1881WobbeIndex 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 0.055

N2 12.30 12.015 -0.285

CO2 2.23 2.209 -0.021

C6 N/A 0.077


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 0.25 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

WobbeIndex 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 -0.02

N2 1.10 1.12 0.02

CO2 1.55 1.543 -0.007

C6


-0.0568


-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 0 0

N2 11.23 11.344 0.114

CO2 1.72 1.69 -0.03

C6


-0.0002


-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 0 0

N2 9.80 9.793 -0.007

CO2 3.01 2.979 -0.031

C6 0.00 0 0



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.

Thank You

evaluating a tunable filter spectrometer online gas analyzer · saudi aramco: public • very...

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