Back to the Basics: NeSSI or Not NeSSI the Basics Are the Same

Transcription

1 Falcon Analytical makers of the... Back to the Basics: NeSSI or Not NeSSI the Basics Are the Same IFPAC 2013 John Crandall, President Falcon Analytical Dr. Brian Rohrback, President Infometrix Mike Cost, Parker Intraflow tm Product Manager Copyright Falcon Analytical 1/30/ AEI Drive Lewisburg, WV Tel: (304)

2 Quantitative Chemical Analysis Fischer and Peters, Third Addition August, 1968, page 3 The Methods of Quantitative Analysis A complete quantitative determination generally consists of four major steps: Obtaining a sample for the analysis Separation of the desired constituent in a measurable form Measurement and calculation of the results And drawing conclusions from the analysis. 2

3 Quantitative Chemical Analysis Fischer and Peters, Third Addition August, 1968, page 10 Sampling In practical situations, however, obtaining a sample suitable for analysis is often a source of major difficulty and frequently limits the validity of the final result. 3

4 The Quantitative Chemical Analysis Project: 8 Stream microscale Bioreactor System Continuous monitoring was required Production monitoring for a specialty chemical Nutrient monitoring & feed rate Oxygen monitoring & feed rate for microbes There are multiple small systems In this case there are 8 reactors Process flow rates are small < 1 liter/minute Calibration for the semivolatile organic is problematic Manual sampling & monitoring is virtually impossible Fermentor off gas analysis was required Sampling the broth is complicated The broth will plug virtually any automatic sampling mechanism The off gas concentration indicates production yield (concentration in off gas is proportional to production in the broth) 4

5 Automation Strategy Overall Strategy Use smart software Control critical parameters: T, P, and especially flow rate (don t suck the reactors dry) Plumbing Parameters IntraFlow NeSSI Switches streams & controls flow rates Performs periodic autocalibration sample via the permeation calibration system Monitors critical parameters: T, P, F 5

6 Automation Strategy Calidus & Chrom Perfect Process Control (CPPC) Performs chromatographic analyses CP operating Calidus, NeSSI & directing data flow is the master Receives permissions & reports (alarms) results from/to LIMS LineUp & InStep Aligns chromatograms to target chromatogram Assesses results as consistent with expectations or outlier, sound the alarm 6

7 8 Stream Gas Analysis System Implementation Electronics, I/O 8 Stream NeSSI Sample System System Computer Calidus Fast Gas Chromatograph 7

8 Description Electronics, I/O Power supply Ethernet switch 24 VDC outputs Electronic to pneumatic switching MODBUS modules are available to fit here 8 Stream NeSSI Sample System Block valves Pressure gauge Flow rotameters Permeation tube calibrator System Computer Sample transfer line Gas sample valve oven Calidus Fast Gas Chromatograph 8

9 2 4 Normal Sample Flow Through System PORTER MADE IN USA TO VACUUM PUMP AND VENT V E N T Sample Line Input #1 Sample Line Input #2 Sample Line Input #3 Sample Line Input #4 Sample Line Input #5 Sample Line Input #6 Sample Line Input #7 Sample Line Input #8 Close Position Close Position Close Position Open Position Close Position Close Position Close Position Close Position PORTER MADE IN USA PORTER MADE IN USA PORTER MADE IN USA PORTER MADE IN USA PORTER MADE IN USA PORTER MADE IN USA PORTER MADE IN USA Normal State of the 6Port Gas Diaphragm / Plunger Valve 6 3 PORTER MADE IN USA Gas Output G.C. Inlet Calibration Input From Calidus GC To Calidus GC NOT Actuated Normal State of the 6Port Gas Diaphragm / Plunger Valve On Top Of G.C. Air Input 6 9 Carrier Gas

10 The Lessons We Learn in Process Analytical Chemistry Over & over & over again! In measurement and calculation of the results Repeatability only requires a STABLE calibration standard Reproducibility requires not only a stable standard but must also have CONSENSUS values for the calibration standard Precision and accuracy require stable & ACCURATE calibration standards Lesson: selecting, preparing & using a vapor phase semivolatile hydrocarbon standard must be done with GREAT care In bags, the concentration in vapor can be no more than the expected value but is probably less from condensation The calibration standard must be chemically & thermally stable Temperature control is critical for concentration stability If properly implemented, permeation calibration devices are advised. 10

11 Really Basic Make sure the system has the specified utilities: valve switching 65 psi minimum specified Multiple devices were being fed from a single stage regulator at 65 psi As the compressor cycled, so did the analysis (SV not fully engaged) Compressor reservoir bleeds down, analysis trends down Compressor hits low limit, analysis jumps back up as the switching pressure QUICKLY becomes adequate for the SV The pressure was increased to 75 psi & the saw tooth trend disappeared HOWEVER, the longer term trend is DOWNWARD why? 11

12 4/21/12 12:00 AM 5/1/12 12:00 AM 5/11/12 12:00 AM 5/21/12 12:00 AM 5/31/12 12:00 AM 6/10/12 12:00 AM 6/20/12 12:00 AM Area of peak Original C 10 Terpene Calibration Sample deterioration (decomposition, polymerization something) Calibration peak area is drifting downward continuously as if the liquid calibration material is being depleted. This is not realistic as the calibration system should last months or years at 100 ppm

13 A Surrogate nc 10 Calibration Sample Was Chosen for Stability & Response Equivalency Successive runs ~ every 2 hours Long term area RSD = 0.77% after stable flow from permeation tube is achieved Reproducibility meets the requirements after stable flow is achieved nc 10 is a good surrogate 13

14 The Lessons We Learn in Process Analytical Chemistry Over & over & over again! In obtaining a sample for the analysis Direct sampling of this process is impractical Indirect sampling can be representative (off gas) Sampling STARTS at the FERMENTOR and ends at the Calidus SV Lesson: transporting semivolatile hydrocarbons must be done with GREAT care Tubing must be nonadsorbing to preserve sample integrity Temperature must be above the dew point from the off gas output to the Calidus GC sample valve Flow rates must be appropriate for representative, lag free samples at the Calidus GC sample valve. 14

15 Permeation Tube Calibration: Stream 0 at Constant Temperature & Flow 15

16 Sample Stream 7: fermentor spiked with calibration sample through Tygon 16

17 Sample Stream 7: fermentor spiked with calibration sample through Viton 17

18 Tubing must be nonadsorbing to preserve sample integrity Response at 100 ppm from permeation tube Response spiked at ~ 200 ppm from fermentor Tygon Response spiked at ~ 200 ppm from fermentor Viton Heat traced SS tubing was terminated at the top of the hood. Fermentors were then connected with flexible tubing. Viton is better but why not use heat traced SS tubing all the way from sample point to the analyzer? 18

19 Bag Sample Preparation & Results In known volume of air carefully Inject the liquid through septum Use a heat gun on the bag Watch the liquid evaporate Use the sample immediately What we know Concentration can be NO MORE than the calculated value 19

20 Bag Sampling (was done to check permeation tube accuracy) Heat trace controller Note the 8 streams plumbed are properly heated & insulated 65 o C was specified (above the dew point) The setting is 9 o C low Bag sample is Room temperature without control Connected to the inlet using Tygon tubing 20

21 Permeation Tube Sampling IntraFlow NeSSI All components at constant 65 o C Pressures and flows are well controlled at 20 ml/minute Connection to Calidus All components at constant 65 o C Sample Shutoff valve references atmospheric pressure 21

22 Explanation of Results: as the room cools, sample in the bag condenses on the inside walls. As the room heats, the condensate vaporizes and don t forget Tygon adsorbs semivolatile hydrocarbons. Bag sample at Variable Temperature Permeation Tube at Constant Temperature 22

23 Going Forward Trust the 100 ppm +/1 permeation tube output Requires constant 65 o C and, 20 ml/minute flow rate It can be certified to NIST standards if needed Bag samples should only be used for scouting an application Only use inert, heat traced sample transport tubing Not just into the fume hood but also to the reactors Tygon doesn t work, Viton isn t much better, Teflon might work but Any chance for condensation makes the apparent concentration low as demonstrated with the bag sampling method 23

24 The Sentence Preceding however Sampling Therefore, he (the analyst) seldom needs to be concerned in his laboratory work with the operation of sampling. In practical situations, however, obtaining a sample suitable for analysis is often a source of major difficulty and frequently limits the validity of the final result. In Process Analytical Chemistry, everyone must be concerned with sampling! 24

25 Falcon Analytical makers of the... NeSSI or Not NeSSI: the Basics Are the Same Don t ASSUME everyone has the process analytical experience or that NeSSI can solve all the problems. Questions? Copyright Falcon Analytical 1/30/ AEI Drive Lewisburg, WV info@falconfast.net Tel: (304)