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TDLAS and QF analyzers
application guideAccurate and reliable measurementof H2O, H2S, CO2, C2H2, NH3 and O2

2TDLAS and QF process gas analyzers and natural gas processing

TDLAS and QF process gas analyzers
Advanced spectroscopic solutions for challenging applications
Tunable diode laser absorption spectroscopy (TDLAS) and quenched fluorescence (QF) analyzers possess unique design andperformance characteristics that provide significant advantages over other gas analysis technologies.
• High-resolution lasers provide selective and specificanalyte measurement in complex hydrocarbon gasstreams• Continuous flow of sample gas through the measurement
cell provides an exceptionally fast response to analyte
concentration changes• Laser and detector components are isolated andprotected from process gas and contaminants, avoiding
fouling, corrosion, and damage for reliable long-term
operation• Patented differential spectroscopy technique enables
detection and quantitation of low ppm and sub-ppm
concentrations of H2O, NH3, and H2S in complexhydrocarbon gas streams• Laser spectroscopy uses virtually no consumable items,
providing lower OPEX and requiring less maintenanceand service than other analyzer technologies• Quenched fluorescence (QF) analyzers measureoxygen (O2) in natural gas streams from ppm levels
to percentage levels, and are unaffected by H2S whichcauses measurement errors and depletes electrolyte
solution in electrochemical O2 analyzers

TDLAS and QF analyzers

This guide provides lists of field-proven applications of Endress+Hauser TDLAS and QF analyzers in specific industries.
For more information about a particular application, please visit www.endress.com.

Natural gas and energy transition

Natural gas
Measurement of H2O, H2S, CO2, and O2 in natural gas
pipelines; at production and gathering sites, custodytransfer points, compressor stations, and storage facilities;
and in distribution systems is critically important toprotect pipelines from corrosion and to meet gas quality
specifications. Endress+Hauser TDLAS and quenched
fluorescence (QF) oxygen analyzers have a proven trackrecord of reliability in thousands of installations worldwide.
Natural gas
AnalyteApplication note title

Typical measurement range(s)*H 2O

H2O in natural gas production, storage, transportation anddistribution

0 - 100 ppmv
0 - 2500 ppmv

CO2CO2 in natural gas production, storage, transportation anddistribution

0 - 5%
0 - 20%H 2S

H2S in natural gas production, storage, transportation anddistribution

0 - 10 ppmv
0 - 5000 ppmv

O2

O2 in natural gas production, storage, transportation anddistribution

0 - 100 ppmv
0 - 20%% refers to mol. %.

*Energy transition
As energy sources and gas mixtures continue toshift around the globe, rapid and reliable analysis ofcontaminants in hydrogen and carbon dioxide streams
is vital to ensure safety, process control, and gas quality.
Endress+Hauser TDLAS and QF analyzers serve theseemerging market needs with fast, accurate, stable process
measurements that have no contaminant interferences andnearly zero maintenance.
Energy transition
AnalyteApplication note title

Typical measurement range(s)*H 2O & O 2

H2O and O2 measurements for greenhydrogen production

H2O: 0 - 10 ppmv (H2 specific build); 0 - 50 ppmv (minimum);0 - 6000 ppmv (maximum)
O2: 0 - 10 ppmv (minimum); 0 - 1000 ppmv (maximum)

H2O, H2S& O2

H2O, H2S and O2 measurements
for carbon capture, utilization, andstorage (CCUS) applications

H2O: 0 - 50 ppmv (minimum); 0 - 6000 ppmv (maximum)
H2S: 0 - 10 ppmv (minimum); 0 - 5% volume (maximum)
O2: 0 - 100 ppmv (minimum); 0 - 20% volume (maximum)

H 2O

Carbon capture, utilization, andstorage (CCUS) - CO2 dehydration
with glycol

H2O: 0 - 100 ppmv (minimum); 0 - 2000 ppmv (maximum)

CO2

Carbon capture, utilization, andstorage (CCUS) - CO2 purity after
amine treatment

CO2: 0 - 90% (minimum); 0 - 100% (maximum)

H2O, H2S,O2, CO2

Real-time quality measurements inbiogas and biomethane

H2O: 0 - 50 ppmv (minimum); 0 - 6000 ppmv (maximum)
H2S: 0 - 10 ppmv (minimum); 0 - 5% volume (maximum)
O2: 0 - 100 ppmv (minimum); 0-5% (maximum)
CO2: 0 - 5% (minimum); 0 - 20% (maximum)% refers to mol. %.

*3

4

Liquefied natural gas (LNG) and natural gas processing

Liquefied natural gas (LNG)
The feed gas to liquefied natural gas plants must be treated
to reduce H2O and CO2 levels to 100 ppb and 50 ppm
respectively to prevent these contaminants from freezing up
in cold box heat exchangers and halting gas liquefaction, LNG
loading, and shipments. Endress+Hauser TDLAS analyzers
monitor H2O, CO2, and H2S in the feed gas to baseload LNG
plants to ensure continuous, uninterrupted operation ofliquefaction trains and on-time LNG loading and shipments.

Liquefied natural gas*Analyte

Application note title

Typical measurement range(s)*H 2O

LNG: H2O in dry LNG feed gas

0 - 10 ppmv

H 2O

LNG: H2O in LNG product terminal0 - 10 ppmv

CO2LNG: CO2 in LNG amine unit

0 - 100 ppmv

H 2S

LNG: H2S in LNG amine unit

0 - 10 ppmv
0 - 20 ppmv

Consult factory for alternative measurement ranges

Natural gas processing
Natural gas processing involves separating methane (CH4)from other hydrocarbons, water, and other contaminants(H2S, CO2, mercury, and nitrogen) entrained in raw
wellhead gas to produce pipeline-quality dry naturalgas. Endress+Hauser TDLAS analyzers perform on-line
measurements of H2O, H2S, and CO2 at critical points in thegas treatment process.

Natural gas processing*Analyte

Application note title

Typical measurement range(s)*H 2ONatural gas processing: H2O in molecular sieve dryer vessel outlet

0 - 10 ppmv

H 2O

Natural gas processing: H2O in natural gas product (productpurity/residue gas)

0 - 10 ppmv

CO2

Natural gas processing: CO2 in amine outlet (sweet gas)

0 - 100 ppmv

CO2

Natural gas processing: CO2 in raw natural gas feed

0 - 100 ppmv

H 2S

Natural gas processing: H2S in raw gas feed (produced gas)

0 - 500 ppmv
0 - 5000 ppmv

H 2S

Natural gas processing: H2S in natural gas product(purity/residue gas)

0 - 20 ppmv

H 2S

Natural gas processing: H2S in amine scrubber outlet

0 - 20 ppmv

H 2S

Natural gas processing: H2S in solid scavenger outlet

0 - 20 ppmv

Consult factory for alternative measurement ranges

NGL fractionation products

NGL fractionation products
Wellhead natural gas from some geological formations
contains commercially valuable and recoverable amounts ofnatural gas liquids (NGLs): ethane (C2H6), propane (C3H8),
butane (C4H10) and a mix of C5+ hydrocarbons. Cryogenic
processing is used to separate NGLs from methane andfractionate the NGL mixture into distinct fractionation
products. Endress+Hauser TDLAS analyzers perform
on-line measurements of H2O, H2S, and CO2 in NGL
fractionation products to ensure purity specifications aremet or their intended use and downstream processing.

NGL fractionation products*Analyte

Application note title

Typical measurement range(s)*H 2ONatural gas processing: H2O in Y-grade, NGL fractionation

0 - 50 ppmv

H 2O

Natural gas processing: H2O in ethane, NGL fractionation

0 - 10 ppmv

H 2O

Natural gas processing: H2O in ethane/propane mix, NGL
fractionation

0 - 10 ppmv

H 2O

Natural gas processing: H2O in propane, NGL fractionation

0 - 10 ppmv

CO2

Natural gas processing: CO2 in Y-grade NGL fractionation

0 - 500 ppmv

CO2

Natural gas processing: CO2 in ethane NGL fractionation

0 - 100 ppmv

CO2

Natural gas processing: CO2 in ethane/propane mix NGL
fractionation

0 - 100 ppmv

H 2S

Natural gas processing: H2S in Y-grade NGL fractionation

0 - 20 ppmv

H 2S

Natural gas processing: H2S in ethane NGL fractionation

0 - 20 ppmv

H 2S

Natural gas processing: H2S in ethane/propane mix NGL

0 - 20 ppmv

H 2S

Natural gas processing: H2S in propane NGL fractionation

0 - 20 ppmv

Consult factory for alternative measurement ranges

56

Petrochemicals

Petrochemicals
Production of high purity olefins, ethylene (C2H4), andpropylene (C3H6) involves steam cracking of hydrocarbon
feedstocks such as naphtha or ethane followed by a seriesof unit operations to remove or convert contaminants inthe cracked gas. Endress+Hauser TDLAS analyzers perform
on-line measurements of contaminants (C2H2, NH3, H2O,H2S, and CO2) at critical points in olefins plants and polymer
production.

Olefins
Olefins*Analyte

Application note title

Typical measurement range(s)*H 2OPetrochem: H2O in pure ethylene

0 - 10 ppmv

H 2O

Petrochem: H2O in UNIPOL™ PE process ethylene feed gas

0 - 10 ppmv

H 2O

Petrochem: H2O in cracked gas dryer vessel outlets

0 - 10 ppmv

H 2O

Petrochem: H20 in pure propylene (steam cracker)

0 - 10 ppmv

C2H2

Petrochem: C2H2 in mid-bed of back end acetylene converters

0 - 3000 ppmv

C2H2Petrochem: C2H2 in outlet of back end acetylene converters

0 - 5 ppmv

C2H2Petrochem: C2H2 in pure ethylene

0 - 5 ppmv

NH3Petrochem: NH3 in pure ethylene

0 - 5 ppmv

NH3Petrochem: NH3 in pure propylene

0 - 5 ppmv

H 2SPetrochem: H2S in caustic wash tower inlets

0 - 500 ppmv

H 2SPetrochem: H2S in UOP C3 Oleflex process reactor effluent

0 - 150 ppmv

CO2Petrochem: CO2 in caustic wash tower inlets

0 - 500 ppmv

Consult factory for alternative measurement ranges

SyngasSyngas*Analyte

Application note title

Typical measurement range(s)*CO2Syngas: CO2 in GTL syngas (synthol process) coal liquefaction(CTL/Benfield outlet)

0 - 100 ppmv

Consult factory for alternative measurement ranges

Refining

Refining
Refinery gas streams contain contaminants that canadversely affect operational efficiency, process yields,
and refinery operating margins. Endress+Hauser TDLAS
analyzers perform on-line measurements of H2S and H2O
in process gas streams to help refineries control thesecontaminants, optimize unit operations, and comply withenvironmental regulations.

Refining*Analyte

Application note title

Typical measurement range(s)*H 2O

Refining: H2O in hydrogen recycle for refinery catalytic reformer
H2 recycle streams

0 - 50 ppmv (control)
50 - 500 ppmv (trend)

H 2O

Refining: H2O in continuous catalytic reformer H2 recycle streams

0 - 50 ppmv

H 2O

Refining: H2O in propane/propylene mix

0 - 10 ppmv

H 2O

Refining: H2O in alkylation feedstock

0 - 50 ppmv

H 2O

Refining: H2O in n-butane feed gas to UOP Butamer process

0 - 5 ppmv

H 2O

Petrochem and refining: H2O in instrument air

0 - 100 ppmv

H 2S

Refining: H2S in propane/propylene mix

0 - 10 ppmv

H 2S

Refining: H2S in flare gas

0 - 10 ppmv
0 - 300 ppmv

H 2S

Refining: H2S in fuel gas

0 - 320 ppmv

H 2S

Refining: H2S in hydrogen recycle for catalytic reformer

0 - 50 ppmv
0 - 300 ppmv

H 2S

Refining: H2S in amine treatment unit outlet hydrogen recycle gas

0 - 50 ppmv
0 - 100 ppmv
0 - 300 ppmv

Consult factory for alternative measurement ranges

Get more details for a specific measurement bydownloading the application note.
Simply enter the title in the “Find Products, Downloads, and more...” search field at www.endress.com.

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