Application of Sampling Systems To Microreactors

1
Application of Sampling Systems To Microreactors

• Brian J. Marquardt
• Dave Veltkamp
• CPAC

2
Benefits of Sampling Systems to Reaction 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
• Fast switching of streams for measurement,
  calibration or validation

3
Online Monitoring of a Continuous Microreactor
4
Benefits of Raman Analysis

• Little or no sample preparation is required
• Water is a weak scatterer - no special
  accessories are needed for measuring
• aqueous solutions
• Water and CO2 vapors are very weak scatterers -
  purging is unnecessary
• Inexpensive glass sample holders, non-invasive
  probes and immersion probes
• are ideal in most cases
• Fiber optics (up to 100's of meters in length)
  can be used for remote analyses
• Since fundamental modes are measured, Raman
  bands can be easily related to
• chemical structure (very good for
  fingerprinting)
• Raman spectra are "cleaner" than mid-IR spectra
  - Raman bands are narrower, and
• overtone and combination bands are generally
  weak
• The standard spectral range reaches well below
  400 cm-1, making the technique
• ideal for both organic and inorganic species
• Raman spectroscopy can be used to measure bands
  of symmetric
• linkages which are weak in an infrared
  spectrum (e.g. -S-S-, -C-S-, -CC-)

5
Current Sensor Integration
Online Raman Probe
Continuous Microreactor
Sample Flow Cell
6
Nitration of Toluene Data
7
Formation of Nitrotoluene(s)
8
Benefits of NESSI System for Microreaction
Monitoring

• Control sample stream temperature, pressure and
  flow to sensor
• Ability to insert probe at optimal sensing point
• Flexibility for performing calibration online
  without removing sensor
• Generate real-time calibration and validation
  samples

9
Raman Sensor Module
10
NESSI Microreactor Sampling/Calibration System
Reactor Feed 1
Product Stream
Reactor Feed 2
waste
prod
Raman Probe
11
Summary

• NESSI allows for increased control of sample
  stream at analyzer interface
• Typical pressure and flow are compatible with our
  microreactor
• NESSI enables flexibility in calibration,
  validation, sampling and sensor location
• NESSI may actually take the place of the reactor
  itself in the future

12
Acknowledgments

• Swagelok
• Dave Simko
• Rick Ales
• John Warowski
• Parker/Hannifin
• Steve Doe
• Larry Ricker UW Chem. E.
• Sylvie Theas UW Chem. E.