Transcript Utilizing NeSSI for Analytical Applications

Utilizing NeSSI for
Analytical Applications
Brian Marquardt
Dave Veltkamp
NeSSI Modular Sampling Systems
New Sampling Sensor Initiative
ISA SP76 substrate protocol
Component based gas and fluid
handling systems
Offer flexibility in design and
implementation of complicated flow
systems for process sampling and
analysis
LEGOTM based approach to
process sample handling
Allows for optimal positioning of
analyzers in a process stream
What does NeSSI™ Provide
Simple “Lego®-like ” assembly (√)
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Easy to re-configure
No special tools or skills required
overall lower cost of build – reduce time to configure/install by 75%
improved reliability
lower cost of ownership – reduce total cost by 40%
Standardized flow components (√)
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“Mix-and-match” compatibility between vendors
Growing list of components
Standardized electrical and communication (+)
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“Plug-and-play” integration of multiple devices
Simplified interface for programmatic I/O and control
Advanced analytics (+)
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Micro-analyzers
Integrated analysis or “smart” systems
Where Does NeSSI™ Fit in the Lab
Instrument/Sensor Interfaces
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Design standards make development simpler
Reduced toolset to be mastered
Reduced sample variability to account for
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Calibration/validation built-in
Consistent physical environment for measurement
Stream switching and/or mixing allow generation of
standards to match analytical requirements
Reaction monitoring
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Microreactors and continuous flow reactors
Batch reactors (with fast loop)
Sample Preparation
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Gas handling (mixing, generation, delivery)
Liquid handling (mixing, dilution, conditioning, etc.)
Benefits of Sampling Systems to
Process Analysis
Conditioning and manipulation
of sample introduced to analyzer
Better control of sample physical
parameters
 Phase
 Temperature
 Velocity
Ability to implement sensors at points where measurement
parameters are optimal
Flexibility for performing calibration online without
removing sensor
Fast switching of streams for real-time measurement,
calibration or validation
Raman/NIR/UV-Vis Sensor Module
Sensing Technologies
Gas Chromatography
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Thermal Desorption (?)
Dielectric (√)
Spectroscopies
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IR (?), NIR (+)
UV- Vis (+)
Raman (√)
Fluorescence (+)
Impedance (+)
Conductivity (√)
Refractive Index (√)
Vapochromic Sensors (+)
GLRS (+)
Particle Sizing
 Light scattering (?)
Turbidity (+)
pH (√)
RGA (+)
Mass Spectrometry (√)
LC, SEC, IC (+)
Terrahertz (?)
Natural Gas Property Testing
Collaborative project with
Brooks Instruments to
test new Gas Property
Instrument (GPI) for
Gross Calorific Value and
Wobbe Index of natural
gas
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Adaptation of thermal mass
flow technology to measure
physical parameters of gas
NeSSI™ system used to
generate air/propane
mixtures with known
properties to simulate
natural gas variations
GPI Testing Results
Raw MFC (% Full Flow N2)
Gross Heating Correlation
Corrected (Vol %) Flow
Wobbe Index Correlation
GPI Conclusions
First real application of gas blending or
mixing on NeSSI in our lab
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Developed preliminary LabVIEW software
control for MFCs and pressure transducers
Brooks has agreed to assist in calibrating our
MFCs for multiple gases
GPI results looked fairly good over
planned application range of natural gas
properties
Development of fast and
selective gas sensors using
vapochromic compounds
Vapochromic Probe Design &
Sensing System
GAS FLOW
Vapochromic
Film
3000
Intensity
Excitation Fiber
Light Source
Blue LED
0% relative humidity
100% relative humidity
2500
Probe Tip
Dual Fiber
Probe
Emission Spectra of
[Pt(CN-cyclooctyl) 4][Pt(CN)4]
2000
1500
1000
500
0
400
500
Collection Fiber
600
700
Wavelength
Spectrograph
& Detector
800
900
Example NeSSI Sensor Interface
Sensor is a vapochromatic compound
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Responds to different compounds by intensity
and wavelength shifts in fluorescence signal
Optical detection using simple VIS
spectrometer
LED excitation light source
Simple reflectance 2 fiber optical measurement
Use of BallProbe to provide single-sided
optical interface
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Vapochrome coated on ball surface
NeSSI™ system to control delivery and
mixing of gas stream
Vapochromic Humidity Sensor
100
80
Predicted Y
Elements:
6
Slope:
0.999824
Offset:
0.007585
Correlation: 0.999912
RMSEC:
0.342323
SEC:
0.374996
Bias:
-1.272e-06
- Measurment time – 100 ms
- 3 reps per concentration
per80.Mas
per70.Mas
60
per50.Mas
40
per30.Mas
per20.Mas
20
per10.Mas
0
0
20
humid meas, (Y-var, PC): (humid meas,2)
• 2 PC calibration model
• humidity range: 10 – 80%
• Ohmic feedback control
humidity generator used for
reference stds.
Measured Y
40
60
80
100
Oxygen Gas Sensor Calibration
- 2 PC PLS model
- range = 0-100%
Vapochromic O2 Sensor vs
Electrochemical DO probe
Response of Optical and DO Probes, Second Timed Exp.
120
DO reference measurement (O2 %)
0
DO Probe
100
100
80
200
60
300
40
400
20
0
50
100
Elapsed Minutes
150
Sensor Optical Intensity (relative counts)
Optical @560nm
200
Optical response inverted and offset for comparison
Vapochromic O2 Sensor Response
Vapochromic BTEX Sensing
Vapochromatic compound screening for
benzene, toluene, ethylbenzene and mxylene (BTEX) sensitivity and selectivity
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Need to find the best available compounds for
sensor array approach
Initial milestone: benzene detection
Establish sensitivity
(can we detect low enough levels?)
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Characterize interferents
(can we distinguish mixtures?)
NeSSI™ system to control delivery and
mixing of gas streams
NeSSI Gas/Vapor System
Single inlet
line (N2)
-NeSSI substrate with 3 MFC’s
-2 bubblers for vapor generation
Outlet line
to flow cell
Standard
Ace Glass
impingers
Optical Flow Cell
Flow cell is a simple cross
fitting
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6-around-1 fiber optic for
source and collection
Delrin rod with sensing
compound coated on end
Multiple crosses can be
chained together for
screening several
compounds at once
Optical detection using
simple VIS spectrometer,
LED excitation light source
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Simple reflectance optical
measurement
Vapochromic NeSSI Sensor Design
simple design
reversible response
low power
inexpensive
NeSSI compat.
fast response times
high quantum efficiency
long term sensor stability
sensitive to a variety of analytes
large number of available vapochromic
compounds (selectivity)
Experimental Details
Three gas streams mixed prior to outlet
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MFC #1 pure N2 carrier (no bubbler)
MFC #2 run thru bubbler with benzene liquid
MFC #3 run thru empty bubbler (diluter)
MFC #1 and MFC #2 flow summed to 50% full
flow (FF, 250 sccm)
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As bubbler flow ↑ carrier flow ↓
MFC #3 held at either 50% FF or 5% FF
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Additional level of dilution between runs
Spectra collected every 2 seconds
LabVIEW program automates setting flow rates
on MFCs, sequence timing, and data logging
Experimental Design/Program
MFC #1 (carrier)
MFC #2 (bubbler)
Duration (seconds)
50
0
60
48
2
90
46
4
90
44
6
90
42
8
90
40
10
90
30
20
90
20
30
90
10
40
90
0
50
90
25
25
90
50
0
180
Typical Automated Response
Full Spectrum Response
Vapochromic Response
* MFC #3 run at 5% FF rather than 50% FF
Vapochromic Response
These are the 2 most
sensitive compounds
of the 6 looked at in
this study
There is plenty of
optical sensitivity to
go to lower conc.
May need to
implement “reset”
techniques to zero
response
Vapochromic #4 Response
Differential response!!??
Screening Conclusions
Early results look good for benzene
sensitivity
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2-3 candidates
Clearly need more dilution capability
Need to speed up the screening
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Multiple simultaneous compounds
Switching/multiplexing NOT the answer
New multichannel spectrometers will improve
screening
New Gas Sensor Testing System
More capability to generate analytical vapors, gas blending, and
on-line dilution of vapor streams for method development work
Two systems (one at CPAC, the other at UM) will facilitate
collaboration with Kent Mann
NSF Funding applied for (Aug. 06)
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Bob Sherman, CIRCOR, committed to providing one system
Fuel Cell Research
Goal: to study the water uptake properties of Nafion 112
by varying the relative humidity of the input gas streams
to better understand membrane hydration and its effects
on fuel cell performance.
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Senior Project for ChemE undergrad student team
NeSSI™ System for gas flow and humidity sensing
3 Voltmeters,1 Ammeter
Thermocouple and
Humidity sensor
Thermocouple and
Humidity sensors
H2 in
PEM Fuel Cell
Both Streams
Purge to outside
environment
Air in
Fan/Blower
Or Pump
Tank (might run system
without a tank)
Fuel Cell (cont.)
Simple NeSSI system design being built
by Swagelok
Preliminary system calculations done by
students
Vapochromic humidity sensors designed
Expect this activity begin this summer
Fluid Dynamics Modeling
Project with Dr. Finlayson and
undergrad student Daniel
Yates, Chem. E.
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Utilize NeSSI™ components as
objects for computation fluid
dynamics modeling
Availability of NeSSI™ systems
and parts allows for experimental
work to verify/test model results
Provides academic training
and exposure to real-world
hardware in a compact and
rugged platform
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Can start simple and add
complexity by including more
components
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Where are we now?
Development continues on control system
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Data I/O, comm., and control hardware
Software for DAQ, automation and control
NeSSI microreactor system becoming reality
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Parker Intraflow™ fluidic system delivered
IMM, Microglass, CPC mixers and reactor
components here or coming soon
LC, Raman, dielectric, RI detection
Headspace and gas analysis systems
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Horiba RGA analyzer running
Vapochromic sensors being designed and tested for
NeSSI applications
GC interface to NeSSI under development with
Infometrix (WTC Proposal submitted)