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Maintaining Gas Stream Purity in Analytical Applications April 18, 2012 Instructor: Frank Kandl

Maintaining Gas Stream Purity in Analytical Applications April 18, 2012 Instructor: Frank Kandl . Frank Kandl. Frank Kandl Product Manager Specialty Gas Equipment for Airgas

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Maintaining Gas Stream Purity in Analytical Applications April 18, 2012 Instructor: Frank Kandl

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  1. Maintaining Gas Stream Purity in Analytical ApplicationsApril 18, 2012Instructor: Frank Kandl

  2. Frank Kandl • Frank Kandl • Product Manager Specialty Gas Equipment for Airgas • Frank Kandl is the product manager for specialty gas equipment at Airgas, he has over 30 years experience in design and manufacturing of gas delivery systems with Airgas and Air Products. He has vast experience in high purity systems for gas chromatography and other analytical applications, as well as ultra high purity systems for Nano and Semiconductor applications. • Frank has designed regulators and other components for these systems, and has been recognized with awards. He has written several articles in publications in the chromatography market. He has presented and chaired short courses at various Pittcon Conferences, as well as other conferences and trade shows. He has made presentations in the US, Mexico, Germany, Turkey, Spain, China, and Malaysia. • He has initiated several design changes to the standard configurations used for gas delivery systems and components used in these systems to ensure the purity of the gas is maintained as well as containing and removing any contaminants that have entered the gas path or been generated by components in the system. These changes ensure consistent results in processes.

  3. Course Objectives for YOU • Learn to identify causes of inconsistencies that prevent you from getting peak performance from your GC. • Understand the characteristics of carrier gases, fuel gases, and all the components of the gas stream • Understand which are the right components of a gas delivery system that are required to achieve consistent results • Understand why purifiers could be creating performance issues and how a few simple modifications can create the consistent results your require.

  4. Agenda • Understanding of the true purity of high purity gases, and which is the correct purity for your application • Learning how to specify the correct purity for your application and purchase the gas at the best pricing • Understanding the components of a high purity analytical gas delivery system • Learning to optimize the gas delivery system and it components including column and purifier life All together : • Learn to improve efficiencies and cutting gas usage • Safety requirements for a carrier or fuel gas system • Applying what you have learned to your specific process

  5. What Gas Purity Performs The Best ? Lowest purity … …that performs and … …doesn’t damage the equipment.

  6. The “Total Purity Paradox” • Gas purity is confusing when dealing with trade names or grades • Purities range from 98.0% to 99.9999% with no apparent standardization • Grade names for gases, unlike chemicals (IUPAC), are not regulated or characterized by any organization • In truth, the total purity falls well short of characterizing the purity of specialty gases

  7. and Common mistakes • A Zero Grade is a Zero Grade • What is a zero grade ? • All five 9’s pure gases are the same • Why do gas people always talk in 9’s ? • A cylinder is a cylinder

  8. Company A Helium Purity Company B BIP N/A 99.9999+% Research, Chrom Research 99.9999% UPC N/A 99.9995% UHP/Zero 99.999% UHP N/A Chrom 99.998% HP N/A 99.997% N/A Zero, HID, HP no assay Don’t rely on names! 3-fold Price Difference!!

  9. How is gas purity determined? Gas Purity (by Difference) = Gas Purity 100% – Analyzed Contaminants

  10. ppm of impurity Impurity Percent Purity Percent Let’s convert ...Percent to Parts Per Million 99.0 1.0 = 10,000 99.9 0.1= 1,000 99.99 0.01 = 100 99.999 0.001 = 10 99.9999 0.0001 = 1

  11. 99% Pure 95% Pure Which spoonful of sugardo you want?

  12. 99% Sugar 1% Rat Poison 95% Sugar 5% Salt Now which one do you want?

  13. Company X Company Y Company Z % Purity 99.997% 99.999% 99.998% Inert A 10 ppm 5 ppm N/A Inert B 10 ppm 5 ppm N/A Reactive C 10 ppm N/A 20 ppm “Purest” Gas Could Be Biggest Problem!! Don’t rely on the gas purity!

  14. Actual Helium Comparisons Company 1 Guaranteed Analysis UPC Purity 99.9995%* N2 < 5.0 ppm O2 < 1.0 ppm THC < 0.5 ppm H2O < 1.0 ppm *Excluding neon Company 2 Typical Specifications* UHP Purity 99.999% N2 < 5 ppm O2 < 1 ppm THC < 0.5 ppm H2O < 3 ppm *Excluding neon Company 3 UHP Purity 99.999% No Guarantees! Company 4 UHP Purity 99.999% Sum of N2, O2, Ar, CO, CO2, THC as CH4, and H2O < 10 ppm Company 5 UHP Purity 99.999% (Neon-free basis) H2O < 1 ppm Company 6 UPC Purity 99.9995% N2 < 2 ppm Ne < 2 ppm O2 < 1 ppm THC < 0.4 ppm

  15. What’s the “Rat Poison”for your processes? • FID (NPD, PID, FPD): THC, Moisture • TCD: Oxygen, Moisture, Other Inerts • ECD: Halogens, Oxygen, Moisture • Hall: Halogens, Oxygen, Moisture, Hydrocarbons • MS/GC: Organics, Halogens, Inerts Source: LC/GC; Vol6 No.9

  16. FID Why use good H2 and He, yet use “bad” air? IT’S INCONSISTENT! Quality Gas RequirementsHave You Made The Right Choices for all of the gas used in your processes? Hydrogen Helium Air

  17. Water’s bad. … need betterwater! DirtyStraw Clean Water Bad analytical performance, no consistencies, gas usage (= costs) keeps climbing • Situation • Problems with getting consistent results • “Helium supply” concerns • Purchasing high purity gas – old gas delivery system • Gas usage continues to climb • Gas supplier suggests he goes to a higher purity carrier gas, says it solves everything • Is this the best choice?

  18. Water’s bad. … need betterwater! DirtyStraw Clean Water Bad analytical performance, no consistencies, gas usage keeps climbing • Customer has chosen the solution recommended by his gas supplier • Switched to higher purity gas • Doubled his gas cost • In reality without an evaluation of the gas delivery system, it will not clean up the problem, and has not • Problems continue • Whatother choices do you have ? • Have the gas company (or a specialist) review the gas delivery system • Gas conservation • Switch carrier gases

  19. Lets first look at the gas delivery system • What do we know about the gas • Purity • You have defined the impurities and their levels • What do we know about the gas delivery system • Can it maintain the purity ? • Does it require purging after cylinder change out ? • Does it have purifiers in line ? • Are they maintained ? • Are they the correct type • Are the purifiers the source of the problems ? • What will it take to make the problems go away ?

  20. A common problem

  21. We need to make sure the straw is clean

  22. Are You Drinking “Pure Water Througha Dirty Straw?” Equipment and Piping • Quality gas requirements is the "first" part of any instrument installation and getting consistent results • The gas delivery system can minimize your gas usage, and optimize the performance of your processes • High purity components are required • Correct choice will have a positive effect, incorrect will have a dramatic negative effect • Eliminate leaks • Typically more gas is leaked or used in purging than in the actual process • Lets see how simple changes can be made

  23. Typical gas management system, been the same for years Lots of components Lots of connections Lots of sources for contamination Lots of way to improve

  24. Modern Gas Management SystemCombine components, reduce connections

  25. Are these gas stream components or Are they gas stream contaminates ?

  26. Initial leak source and the most criticalStarts at the first connection • Never use Teflon tape on a cylinder connection • Connection leak integrity is either metal to metal or with and approved soft seal washer Graphics source Supelco

  27. CGA connection Check valve CGA : • Maintains the system under positive pressure • This is critical and will have dramatic affect on your processes • Minimizes the amount of air that can enter the system • Controlling the potential volume of air, allows the purifiers to work as de-signed • Eliminates the need to purge after cylinder change out • Eliminates unnecessary gas usage to recover a stable base line • Reduces gas usage, creates consistencies, extends component life

  28. Flexible pigtails • Never use flexible pigtails with Teflon inner core • Teflon pigtails are only leak tight in air, nitrogen but not helium or hydrogen • Molecules small enough to diffuse out of the hose are small enough to enter into the gas stream when flowing • Teflon pigtails on the high pressure side of a regulator will permeate 5 – 8% of the cylinder volume • Always use stainless steel flexible core pigtails as these are leak tight in helium and hydrogen service Brass connector indicates if the pigtail has a Teflon core

  29. Primary way contaminants get into the gas stream • Contaminates in the atmosphere enter the system whenever the connection to the cylinder is broken during cylinder change out. • That big swish you hear is the start of your problems • Contaminates are mixed with the gas and pushed into the system when the new cylinder’s valve is opened and pressurizes the system • Contaminates that enter the system, the three we never want in our processes • Moisture • % in atmosphere depends on the weather • Oxygen • 20% in atmosphere or we are not breathing • Hydrocarbons • Always in the air, one reason why we have emissions testing for cars

  30. Individual cylinder regulators • There are two types of regulator design • Forged Body which is old technology • Bar Stock which is new and specifically for analytical applications • Issues with forged body regulators. • Once contaminates enter the regulator they take longer to remove, if at all, due to poor sweep pattern. • Continuously mixing contaminates with the gas. • Longer to recover base line. • Inconsistent process results. • Inconsistent results cost $’s. • There is no regulator made with a tee handle that is suitable for analytical applications

  31. High purity analytical regulators What design features should the regulator have? • Bar Stock Construction • Low "dead" volume to minimize contamination • No dead spots in the gas path • Has 5% of internal volume of a forged body regulator • Check valve cylinder connection • Stainless steel diaphragms • Contaminants cannot be absorbed and then off gassed • Diaphragm "packless" or non lubricated needle valves • Cleaned for all analytical applications • Type of detector should not determine the cleaning specification

  32. Purifiers • Purifiers only have a certain capacity to remove impurities based on • Concentration • Velocity • Volume of the media to absorb the contaminate • Purifiers should only be used as a safeguard, not as a way to continually clean the gas stream • Purifiers react to impurities; there should not be impurities continuously in the gas stream • All purifiers should have these features • Check valve connections to maintain the system under pressure when changing • Indicating/Warning media so you know when they are saturated and what contaminate is causing the saturation

  33. Types of purifiers Non-Indicating — Worse Choice Most Popular Typically Surface Absorbent; Contaminates system when break through occurs, no indication when saturated Indicating type, but exposes process line to contaminates Second Best Choice, Physical Absorbent media with saturation indicator, base and connection have check valves that Maintains the system under pressure Provides a visual(although unclear) indication of saturations

  34. Types of purifiers • Really Your Best Future Choice : • Next Generation to Market • Chemically Absorbent O²-media, which do not release the trapped impurities when saturated like with physical adsorbent • Excellent best-in-class purifying power w. < 1 ppm rest-impurities • Saturation indicator as visual and/or audio alarm, so MUST be seen and/or heard (should not be a vague orhardly visual colour change) • Purifier base and connection have check valves : • Maintains the system under pressure • Provides a visual indication of saturations • Purifiers which are possibly integrated into the GC and indicate their status via the GC display

  35. Types of purifiers • Please be aware of following : • gases go through the gas lines at high speed during pressurization • that means that during that phase, the purifiers are dealing with high gas flows • no purifiers are meant to work under these velocities • also adsorbents and chemical reactions need some time to do their work properly • This being said, we have to realize that even good purifiers can not • justify to use bad-quality gases ; purifiers should be seen as • „policemen“ who warn against impurities and can remove these during • the analysis process but not as standard to upgrade low quality gas to • higher quality

  36. Put the purifiers where they can be seen and maintained • Purifiers need to be positioned where they can be seen and maintained, especially if they have saturation indicators • If you can combine purifiers with other components it is an advantage as it reduces connections

  37. Carrier gas flows are very low to a GC Flows based on the GC operating 24hrs/7day: Septum Purge   2 – 3 cc/min     Column Flow    .1 to 6.5 cc/min     Split vent        15 to 100 cc/min     Make-up gas    20 to 30 cc/min     Fuel gas            20 to 30 cc/min Helium usage potential  =  column flow + septum purge + split vent flow + make-up gas           Low usage             =   .1 +2 + 15 + 20  =         37.1 cc/min           High usage           =   6.5 + 3 + 100 + 30 =     139.5 cc/min If you include the fuel gas once switching to hydrogen             Low usage            =    37.1 + 20 = 57.1 cc/min              High usage           =    139.5 + 10 = 149.5 cc/min If the customer uses nitrogen for the make-up gas you can subtract 20 or 30 cc/min from the helium or hydrogen numbers. Therefore  we see usage as low as 27.1 to as high as 149.5 cc/min.  Or for hydrogen potential gas use you see.   Low usage 27.1 cc/min = 0.0574cubic feet/hour or 41.34 cubic feet in 30 days running 24 hours a day High usage 149.5 cc/min = 0.317 cubic feet/hour or 228.02 cubic feet in 30 days running 24 hours a day There is between 225 – 300 cubic feet of helium in one cylinder Remember this is for one inlet and most GC have two inlets and you can double these flows.  Or at least you can take the high usage and double it for two inlets.  Therefore your range of gas usage can be as low as  27.1 cc/min (41.34 cubic feet/month) or as high as 299 cc/min ( 228.02 cubic feet/month).

  38. Open Discussion

  39. Contact Information Frank Kandl for USA & The AmericasC/O Airgas • 6990S Snowdrift Rd • Allentown, Pa 18106 • Phone 610-336-4522 Ext 4111 • Mobile +1-484-695-7606 • Email frank.kandl@airgas.com Victor Geijsels for International Territories • Baden-Baden, Germany • Mobile +49-16094951949 • Email victor-geijsels@gmx.de Dr. Chromatography - Reggie Bartram, USA for your chromatography questions reg. gas management or related topics • regbart@comcast.net • Visit our website for a lot of useful information and reference material • www.airgasSGcatalog.com

  40. Thank you for attending

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