SS2100 - H2O Ethylene Purity (Product or Polymer Feed) Analyzer Solution

Application Note

 Water Control and Reduction
As Ethylene is separated from Ethane in a cryogenic distillation, the cracked gas must be dried, typically over Molecular Sieves and the Ethylene product is quite dry. However, from that point on, Ethylene can pick of traces of water from transportation in pipelines and ships, storage in salt caverns, and other handling. Molecular Sieve dryers can be used to dry off-spec Ethylene.

Traditional Measurement Solutions
Vibrating crystal, AlO3 capacitance probes and electrolytic moisture analyzers have been the traditional methods for monitoring the levels of water in Polymer Grade Ethylene. These methods suffer from slow wet-up and dry-down time, slow drift in calibration and sensitivity to contamination Due to the very short residence times in Ethylene feed storage vessels and the desired to measure Ethylene in flowing pipelines, the delay in measurements can easily lead to excursions in concentrations before it is detected.

SpectraSensors' Solution
The SpectraSensors SS2100 is the ideal solution for Ethylene purity applications. The use of Tunable Diode Laser technology means that analysis results can be updated every second. Furthermore, the high resolution that is inherent to the laser eliminates errors due to interferences which have hampered other spectrometric approaches. Also, the non-contact nature of the measurement with no moving parts in the analyzer means that the analyzer is simple to operate and little routine maintenance is needed.

Typical Stream Composition

Component	Unit	Typical Concentration	Min. for Application	Max. for Applicaiton
Ethylene (C2H4)	Mole%	99.95	99.9	100
Water	ppmw	<1	0	5
Acetylene (C2H2)	ppmw	<1	0	5
Carbon Monoxide (CO)	ppmw	0.5	0	3
Carbon Dioxide (CO2)	ppmw	< 1.0	0	5
Hydrogen (H2)	ppmw	<1	0	5
“Light Inerts” (C1+C2+N2)	ppmv	100 - 200	0	1000
Propylene (C2H6)+	ppmw	3000	0	10
Total	Mole%	100

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Data Sheet

Performance
Target Components	Water in Pure Ethylene
Typical Measurement Ranges	0 – 10 ppm*
Typical Precision	± 0.05 ppm or 2% of Full Scale (whichever is greater)*
Measurement Response Time	1 to ~60 sec*
Principle of Measurement	Differential Tunable Diode Laser Absorption Spectroscopy (H2O Scrubber included)
Environmental Temperature Range	-20º to 50ºC (-4º to 122ºF) -10º to 60ºC (14º to 140ºF) optional
Sample Inlet Pressure	70 kPag (10 psig) typical 210 kPag (30 psig) maximum
Cell Temperature	Maintain at 50ºC +/- 0.2ºC
Maximum Cell Pressure	70 kPag (10 PSIg)
Sample Flow Rate	3 - 4 L/min (6.4 to 8.5 scfh)*
Validation	A certified blend of H2O in Nitrogen balance is diluted with dried sample in the sample conditioning system under flow control
Electrical
Power	100-240 VAC, 50-60 Hz standard
Max Current	Controller: 1 A @ 120 VAC
Controller to Cell Cable Length	1m standard (3m, 5m & 10m available optionally)
Communication	Current Loop Output 4-20 mA Isolated, 1200 ohms @ 24 VDC max load Serial: ASCII Text RS232C standard Modbus RS232C
Digital Outputs	4 ea. 12 VDC for valve operations Scrubber (if required), Process/Val, Val 1, Val 2 5 SPDT (Form C) Dry Contact Alarms Common Fault, Val 1 Active, Val 2 Active, Val Fail, one user-assignable to any alarm
LCD Display	Concentration, Cell Pressure and Temperature, Diagnostic Data
Physical
Controller Enclosure	NEMA 4X - 304 Stainless Steel standard
Controller Dimensions	343mm H x 305mm W x 165mm H (13.5" H x 12" W x 6-7/16" D)*
Weight Approximately	13.1 Kg (28.6 lbs)*
Sample Cell Dimensions	28m cell for ranges <100 ppm 559 mm H × 127 mm W (22” H × 5” W)
Sample Cell Construction	316L Series Polished Stainless Steel standard Siltek® coated
Number of Sample Cells	1 (single channel SS2100) or 2 (dual channel SS2100)
Area Classification	CSA Certified for Class I, Division 2, Groups ABCD Temp Code T3C  ll 2G Ex d llB+H2 T5; Tamb : -20 ÷ +60 °C
Dimensions with Sample System	1678 mm H x 613 mm W x 427 mm D (66” H x 24-1/8” W x 16-13/16” D)
Weight with Sample System (approx.)	68 kg (150 lbs.)
* Application specific; consult factory

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Drawings

Typical Accessories

Photos

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