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

Application Note

 Water Control and Reduction
Propylene is typically shipped via pipeline, and is sometimes stored in underground salt caverns, so measurement of Propylene purity at custody transfer points is often required. Before being processed in to polymers, Propylene is pre-treated to remove water and other contaminants using alumina and/or molecular sieves depending on the concentration of contaminants. These must be monitored for optimum efficiency and potential channeling and early break-through.

 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 Propylene. 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 Propylene feed storage vessels and the desired to measure Propylene 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 Propylene purity applications. The use of Tunable Diode Laser technology means that analysis results can be updated every second. Furthermore, the high resolution which is inherent to the laser eliminates errors due to interferences which have hampered other spectrometric approaches. 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.

SpectraSensors applies differential spectroscopy where the sample is dried using a metal getter technology and the background spectrum of the sample is collected. The dryer is then bypassed and the wet sample spectrum is collected. The dry spectrum is subtracted from the wet spectrum to get a sensitive measurement free of background gas interferences. The dryer has a typical lifetime greater than 18 months, and is the only consumable part of the analyzer.

 

Component	Unit	Typical Concentration	Min. for Application	Max. for Applicaiton
Propylene (C3H6)	Wt%	99.75	99.5	100
Water	ppmw	<2	0	100
Ethylene (C2H4)	ppmw	50	0	100
Ethane + Propane	Wt%	0.25	0	0.5
Diolefins + Acetylenes	ppmw	<10	0	25
Carbon Monoxide (CO)	ppmw	<10	0	30
Carbon Dioxide (CO2)	ppmw	< 1.0	0	2
Oxygen (O2)	ppmw	<1	0	2
Total	Mole%	100

 

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Data Sheet

Performance
Target Components	Water in Pure Propylene
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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