UOP 1001-2014 Chloride and Fluoride in Liquefied Petroleum Gases (LPG) by Combustion Ion Chromatography (CIC).pdf

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1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB

2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2014 UOP LLC. All rights reserved. Nonconfidential UOP Met

3、hods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at servceastm.org, 610.832.9555 FAX, or 610.832.9585 PHONE. Chloride and

4、Fluoride in Liquefied Petroleum Gases (LPG) by Combustion Ion Chromatography (CIC) UOP Method 1001-14 Scope This method is for determining trace concentrations of chloride and fluoride in liquefied petroleum gases (LPGs) by Combustion Ion Chromatography (CIC). This method has a range of quantitation

5、 from 1 to 1500 mg/kg (mass-ppm) for fluoride and chloride. References Instruction Manual for Automatic Quick Furnace, Model AQF-2100H, www.cosa- UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method A reproducible volume of a liquefied petroleum gas sample is introdu

6、ced into a multi-position horizontal furnace under controlled temperature and moisture. The sample is then combusted in a pyrohydrolytic, oxygen enriched environment. The halogens in the sample are converted to hydrogen halides and halogen gas. These gases are then absorbed into a solution of consta

7、nt volume. An aliquot of the solution is injected into an ion chromatograph (IC) where chloride and fluoride are separated by anion exchange and measured by a conductivity detector with ion suppression. External standards are used for quantitation. Apparatus References to catalog numbers and supplie

8、rs are included as a convenience to the method user. Other suppliers may be used. Chromatographic column, IonPac AS11-HC Analytical, 250-mm length by 4-mm ID, Dionex, Thermo Fisher, Cat. No. 052960 Combustion system, AQF-2100H, equipped with HF-210 horizontal furnace, GA-210 gas adsorption unit, ABC

9、-210 Automatic Boat Controller, ASC-250L Liquid Autosampler, GI-240 Gas Injection Box, and AQF Software, COSA Instrument Corp. Newer models from the same manufacturer are also expected to be suitable. Deionized water system, Nanopure Water Purification System with Total Organic Carbon Analyzer, Ther

10、mo Scientific, VWR, Cat. No. 47729-610 2 of 10 1001-14 Ion chromatograph, equipped with a pump, injection valve/autosampler, eluent generator, continuously regenerated trap column, suppressor, conductivity detector, computer, and Chromeleon software, Dionex, Thermo Fisher, Model ICS-2100 Muffle furn

11、ace, compact benchtop, capable of operation at 800 C, Barnstead/Thermolyne, VWR, Cat. No. 30631-230 Refrigerator, laboratory, explosion proof or flammable storage, Fisher Scientific, Cat. No. 97-950 Regulator, argon, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tr

12、i-Gas, Model 3122-580 Regulator, oxygen, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), cleaned for oxygen service, Matheson Tri-Gas, Model 3810-540 Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other sup

13、pliers may be used. References to water mean deionized and distilled water that is subsequently treated to produce ionically pure, 18.2 megaohm-cm, organic-free, water. Adsorption tube, 10-mL, COSA Instrument Corp., Cat. No. MC25000 (replacement) Argon, 99.999% pure, local supply Ball joint with U-s

14、haped tube, COSA Instrument Corp., Cat. No. MC28017 (replacement) Calibration standard blends, LPG, dichlorodifluoromethane (5, 50, 500, and 5000 mg/kg) in isobutene, 10 lbs each, Airgas Specialty Gases, Cat. Nos. X02BI99CLP2C000, X02BI99CLP2C001, X02BI99CLP2C002, X02BI99CLP2C003, respectively Nitro

15、gen, 99.99% pure, local supply Oxygen, 99.999% pure, local supply Pipet, Pasteur, disposable, borosilicate glass, 146-mm length, Fisher Scientific, Cat. No. 13-678-20A Potassium hydroxide cartridge, RFIC EluGen, EGC II KOH, Dionex, Thermo Fisher, Cat. No. 058900 Pyrohydrolysis tube, inner and outer,

16、 COSA Instrument Corp., Cat. Nos. AQ3QPN (inner w/ flange joint), FN2QPG (outer), replacement set MC28002 Quartz wool, fine grade, 10 g, COSA Instrument Corp., Cat. No. MC06175 Septum, sample injection, for use with Automatic Boat Controller, COSA Instrument Corp., Cat. No. MC15652 Toluene, B&J Bran

17、d, 99.8%, VWR, Cat. No. BJ347 Water, deionized, subsequently treated with a Thermo Scientific Nanopure Water Purification Systems with Total Organic Carbon Analyzer to produce ionically pure, 18.2 megaohm-cm, organic-free, VWR, Cat. No. 47729-610 Procedure The analyst is expected to be familiar with

18、 general laboratory practices, the technique of CIC, and the equipment being used, especially LPG cylinders. Dispose of all supplies and samples in an environmentally safe manner according to applicable regulations. 3 of 10 1001-14 Preparation of Instrument The specifics of this procedure are writte

19、n for the COSA AQF-2100H combustion system with GI-240 Gas Injection Box. The procedure using a later model from COSA Instrument or alternative instrumentation would be similar. Follow the instructions provided with the instrumentation being used. Combustion Preparation 1. Assemble and test all comb

20、ustion system components as per the manufacturers specifications. 2. Insert quartz wool in the end of the pyrolysis tube before inserting into the furnace. Do not connect ball joint from GA-210 to AQF-2100H. The quartz wool should fill 3-4 mm from the ball joint end of the pyrolysis tube The wool is

21、 used as a filter to prevent coke from entering the adsorption unit The wool in the pyrolysis tube will become powdery and/or brittle over time. Replace wool if this occurs Inspect pyrolysis tube for devitrification. White discoloration would be signs of devitrification on the pyrolysis tube. These

22、areas will become brittle, crack and cause mechanical failure. If devitrification has occurred, look for cracks in the devitrified area. Replace tube if there are any signs of cracks in the inspected area. Refer to section 6-1-2 of the HF-210 manual for a list of periodic maintenance checks. 3. Turn

23、 on all modules and gases. Turn on the furnace heater. Use the operating conditions listed in Table 1. Table 1 HF-210 Parameters Inlet temperature 730 C Outlet temperature 1050 C Argon GI-240 flow rate 100 mL/min Argon flow rate 100 mL/min Oxygen flow rate 400 mL/min Argon replace time 30 seconds Va

24、lve sel. ON time 1 second ArO2 valve sel. time 10 seconds O2Ar valve sel. time 10 seconds 4. Log into AQF software and connect to the modules needed for operation. a. ABC-210, GA-210, PC These modules are used for analysis of samples and standards using the LPG Injection procedure. 5. When the set t

25、emperature is reached, a pop-up window on the AQF software will notify the analyst to turn on the water pump. Set the water flow rate to 4 for analysis. 6. Select the LPG burn program (see Appendix). 7. Connect ball joint from GA-210 to AQF-2100H. Chromatography Preparation 1. Assemble and test all

26、ion chromatographic system (IC) components per the manufacturers specifications. 2. Install the analytical column and suppressor (configured in recycle mode). 4 of 10 1001-14 3. Turn on IC and set it to the recommended chromatographic conditions in Table 2. Table 2 Recommended Chromatographic Condit

27、ions Analytical column Dionex IonPac AS11-HC Suppressor Dionex ASRS 300(4-mm) Suppressor current 81 mA Mobile phase 27 mM KOH Mobile phase flow rate 1.2 mL/min Column temperature 30 C Background 1 S Analysis time 12 minutes Injection loop 25 L 4. Allow the IC to equilibrate. Typical background condu

28、ctivity should be at or below 1 S. Change the source of deionized water or check the functionality of the suppressor if the background conductivity is above 1 S. Communication Between IC and AQF Software The AQF and Chromeleon software do not directly communicate with each other. The AQF software in

29、itiates the injection into the IC by timed events. Set the time equal to or greater than the IC analysis time in the analysis parameters tab in the AQF software. This will ensure that there will not be an injection into the IC while the instrument is running a sample. A contact closure is set up to

30、relay the signal to the IC to start each sample run once the combustion apparatus fills the sample loop. These connections are made during installation. Operating Conditions Table 1 summarizes the AQF parameters for analysis. These conditions should not be changed. See the Appendix for method editin

31、g for combustion programs. Table 2 summarizes the recommended chromatographic operating conditions for the convenience of the method user. Other conditions may be used, provided they produce the required sensitivity and chromatographic separations equivalent to those shown in the Typical Chromatogra

32、m (see Figure). Calibration Calibration factors are required that relate to the instrument response for each analyte. Detector response is measured in microsiemens (S) units of conductivity. It is proportional to the ionic concentration and the inherent mobility of each analyte type present when mea

33、sured by the conductivity detector. External standard calibration with a linear curve fit is performed using purchased pre-made blends. Calibrate the instrument with calibration standards each day samples are to be analyzed. Do not use standards that are older than the certified date listed on the c

34、ylinders. Constant Volume Function The GA-210 uses a liquid level sensor in order to provide an adsorption solution of constant volume. For 1 to 1500 mg/kg samples in a 10-mL capacity adsorption tube, set the liquid volume sensor to low and the adsorption solution volume to 5 mL. For higher concentr

35、ation samples, it may be necessary to change to the 20 mL adsorption tube, raise the liquid level sensor and increase the adsorption solution volume. 5 of 10 1001-14 Preparation of Standards Pre-made individual blended cylinders may be purchased from Airgas Speciality Gases or other appropriate supp

36、liers. Standards must bracket the sample concentration range. These standards have concentrations listed as the component, not by chloride or fluoride level. The actual analyte concentrations are determined in Calculations. Analysis of Calibration Standard 1. Secure the calibration standard. 2. Conn

37、ect the standard to the GI-240 Gas Box. 3. Set the Carrier switch to LPG and ensure the carrier flow is 100 mL/min. 4. Set the Sampling Valve to Load Position. 5. Set the Purge Valve on the Gas Box to the Open Position and open the calibration standard cylinder to allow the sample to fill the lines.

38、 6. Check all lines and connections from the calibration standard to the GI-240 for leaks. 7. Purge the LPG liquid through the sight glass and sample valve at a slow rate until air bubbles are no longer seen in the sight glass. 8. Set the Purge Valve to the Closed Position and block in the sample. 9

39、. Set the Sampling Valve to the Inject Position. A bright white light will appear in the pyrohydrolysis tube when the sample begins to volatilize. Cumulative multiple injections in the absorption solution increase the effective concentration of the analytes of interest. For low concentrations, it ma

40、y be required to run three cumulative injections to increase the response of fluoride and chloride. For high concentrations, a single injection is sufficient. 6 of 10 1001-14 10. Press the Start button in the AQF software once the combustion is complete The combustion program will cycle through the

41、injection process in the GA-210 which is around 90 seconds. Once the program is complete, the GA-210 will inject and start the IC. Combustion is complete once the bright white light from volatilization dims in the pyrohydrolysis tube. 11. Reset the Sampling Valve to the Load Position. 12. Close the

42、calibration standard cylinder. 13. Set the Purge Valve to the Open Position to clear the lines of sample and pressure. 14. Once the sight glass is clear, Set the Purge Valve to the Closed Position and disconnect the calibration standard. 15. Identify and integrate each peak for the calibration stand

43、ards. Identification can be aided by comparing to the typical standard chromatogram (see Figure). 16. Calculate the response factor for each analyte using the chromatography software or Equation 3 in Calculations. 17. Repeat Steps 1 through 15 with the other calibration standard cylinders. Sample An

44、alysis 1. Prepare the LPG sample you wish to analyze. 2. Pressurize the cylinder to 1700 kPa (250 psig) with high purity nitrogen. Confirm that the sample container can handle the desired pressure, prior to pressurizing Confirm that the cylinder is not liquid full by venting a small amount of the co

45、ntents into a laboratory fume hood 3. Secure the LPG cylinder. 4. Connect the sample to the GI-240 Gas Box. 5. Set the Carrier Valve to LPG and set the carrier flow to 100 mL/min. 6. Set the Sampling Valve to the Load Position. 7. Set the Purge Valve to the Open Position and open the LPG cylinder al

46、lowing the sample to fill the lines. 8. Check all lines and connections from the cylinder to the GI-240 for leaks. 9. Purge the LPG liquid through the sight glass and sample valve at a slow rate until air bubbles are no longer seen in the sight glass. 10. Set the Sampling Valve to the Inject Positio

47、n. A bright white light will appear in the pyrohydrolysis tube when the sample begins to volatilize. If accumulated injections were run on the standards, the exact same number of accumulated injections must be run on the samples, for example if injections were made for the calibration standards, the

48、n three injections are required for the samples. 11. Press the Start button in the AQF software once the combustion is complete The combustion program will cycle through the injection process in the GA-210 which is around 90 seconds. Once the program is complete, the GA-210 will inject and start the

49、 IC. Combustion is complete once the bright white light from volatilization dims in the pyrohydrolysis tube. 7 of 10 1001-14 12. Reset the Sampling Valve to the Load Position. 13. Close the LPG cylinder. 14. Set the Purge Valve to the Open Position to clear the lines of sample and pressure. 15. Once the sight glass is clear, set the Purge Valve to the Closed Position and disconnect the LPG cylinder. 16. Identify each analyte by retention time (see Figure). Integrate the analyte peaks of interest to calculate area response. 17.