WR-Model 933 H2S Natural Gas

		Model 933 H₂S in Natural Gas

THE NEED
A critical measurement of natural gas quality is the concentration of hydrogen sulfide (H₂S). Remarkably, the common technique for making this measurement, lead acetate tape, is at least 70 years old. Users of this archaic technology report general dissatisfaction with it due to: high maintenance, the cost and shelf life of tape cassettes, the need for reagents, difficulty handling H₂S overload conditions, the sensitivity of the technology to ambient extremes, and, not least, used cassette disposal.

There is worldwide need for a low maintenance, reliable H₂S analyzer in order to reduce the high expenses associated with frequent scheduled and unscheduled maintenance.

THE SOLUTION

AMETEK Western Research has responded to the need for a low maintenance, reliable, and rugged H₂S analyzer by developing the Model 933. The Model 933 uses a proprietary sampling technique combined with our exceptionally high resolution multi-wavelength UV optical bench. The result is a unique low level H₂S analyzer that is designed to operate unattended for six months or more. The analyzer responds quickly to changes in H₂S concentration and it quickly self-recovers from extreme upset conditions.

THE MEASUREMENT

AMETEK Western Research's unique sample conditioning system uses frontal elution chromatography to separate and eliminate interfering species. This ensures an accurate analysis of the gas via direct-UV absorption spectroscopy. Two self-regenerating columns are employed in the 933. While one column is conditioning the gas sample, the other is automatically regenerated.

Optionally, the 933 can be configured to output concentration values for COS and methyl mercaptan thereby offering an extremely cost effective solution for monitoring these compounds.

BENEFITS

Extended, unattended operation for up to 6 months or longer
Self-recovery after high concentration H₂S events
Fast response time to increasing or decreasing H₂S concentrations
Concentration measurements of COS and methyl mercaptan optionally available
No consumables, reagents, or disposables other than zero gas

APPLICATIONS

Gas sweetening
Pipeline quality/custody transfer
Synthetic natural gas (SNG)
Blending stations

Specifications
Methodology:	Proprietary frontal elution sampling; nondispersive ultraviolet analysis for hydrogen sulfide (H₂S), carbonyl sulfide (COS) and methyl mercaptan (MeSH)
Full Scale Ranges:	ppm ranges are standard; mg/Nm3 and other ranges are available
Standard Range:	±2% of full scale
H₂S:	0 to 25 ppm min. to 0 to 100 ppm max.
COS option:	0 to 100 ppm min. to 0 to 500 ppm max.
MeSH option:	0 to 50 ppm min. to 0 to 250 ppm max.
Higher ranges are available upon request
Low Range:
H₂S:	0 to 5 ppm min. to 0 to 50 ppm max.
COS option:	0 to 25 ppm min. to 0 to 250 ppm max.
MeSH option:	0 to 15 ppm min. to 0 to 100 ppm max.
Accuracy
Standard range:	±2% of full scale
Low range:	±5% of full scale
Repeatability
Standard range:	±2% of full scale
Zero Drift
Standard range:	less than ±2% of full scale in 24 hours
Low range:	less than ±5% of full scale in 24 hours
Response Time, Excluding Sampling System
H₂S:	less than 30 seconds to 90% response
COS:	less than 60 seconds to 90% response
MeSH:	less than 180 seconds to 90% response
Sensitivity:	0.5% of full scale
Cross-interference:	H₂S concentration measurement—less than 2% of the sum of COS and MeSH
Sample Stream Requirements:	greater than 80% methane, less than 10% ethane, less than 3% propane, less than 1.25% total butanes, less than 0.5% C5+. Maximum water content is 0.6%.1.
Zero Gas:	Instrument zero purity carbon dioxide; UHP nitrogen, or UHP methane. Minimum auto-zero interval is once per 24 hours.
Sample Pressure Requirement:	830 kPag to 13790 kPag (120 psig to 2000 psig)
Typical Flow:	2.5 L/min. (5 SCFH)
Outputs:	Up to 4 isolated 4-to-20 mA, loop or self-powered; 4 non-isolated 1 to 5 VDC; 5 independent sets of SPDT, Form C, potential free alarm relay contacts, 2 A at 240 VAC
Digital Communication:	RS485 Modbus port; RS232/RS485 service port
Power Consumption:	<500 W (excluding sample and vent line)
Power:	104 to 132 VAC, 47 to 63 Hz, <3A 207 to 264 VAC, 47 to 63 Hz, <2A
Ambient Temperature:	0°C to 50°C (32°F to 122°F)
Dimensions:	HxWxD 1185 x 780 x 254 mm (46.65 x 30.7 x 9.97 in.)
Weight:	Approximately 100 kg (220.5 lbs)