UOP 703-2009 Carbon on Catalysts by Induction Furnace Combustion and Infrared Detection.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. MATERIAL SAFETY DATA SHEETS (MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 1971, 1989, 1998, 2009 UOP LLC. All ri

3、ghts reserved. Nonconfidential UOP Methods 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 serviceastm.org, 610.832.9555 FA

4、X, or 610.832.9585 PHONE. Carbon on Catalysts by Induction Furnace Combustion and Infrared Detection UOP Method 703-09 Scope This method is for determining total carbon on catalysts and in other inorganic materials using a high temperature induction furnace carbon analyzer. The method is generally a

5、pplied over a range of 0.01 to 20 mass-% carbon; however, up to 100 mass-% carbon can be determined with appropriate calibration. On used catalyst, the carbon may be present as coke and/or hydrocarbons. If only the carbon present as coke is desired, hydrocarbons are removed by extraction prior to an

6、alysis, as described in UOP Method 602, “Soxhlet Extraction of Catalysts.” Analysis of catalysts containing light hydrocarbons can be problematic due to thermal loss of the hydrocarbons before controlled combustion occurs. For such materials, other methods, such as ASTM D5291, “Instrumental Determin

7、ation of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants,” should be utilized. Analyzers that utilize combustion tube, rather than induction furnace technology may be used if it can be proven that they yield precision data at least as good as that listed herein. References ASTM M

8、ethod D5291, “Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants,” www.astm.org UOP Method 602, “Soxhlet Extraction of Catalysts,” www.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method A sample is weighed int

9、o a ceramic crucible and the required accelerators are added. The crucible is then introduced into a high frequency induction furnace. The sample is combusted in oxygen and any carbon present forms carbon monoxide (CO) and carbon dioxide (CO2). The gas is passed through a purification system to remo

10、ve moisture and dust, the CO is catalytically oxidized to CO2and the total CO2concentration is measured by a solid state infrared detector. After introduction of the sample into the instrument, all subsequent operations are carried out automatically. 2 of 7 703-09 A carbon analyzer manufactured by L

11、ECO Corporation, Model CS-600, was used in development of this method and the accompanying precision statement. Equivalent instruments manufactured by other companies may be used, if they can demonstrate precision equal to that listed herein. Apparatus References to catalog numbers and suppliers are

12、 included as a convenience to the method user. Other suppliers may be used. Balance, readable to 0.1 mg Ball mill, with appropriate grinding vials, SPEX, Model 8000M Mixer/Mill Carbon analyzer, includes halogen trap, LECO, Cat. No. CS-600 Desiccator, VWR, Cat. No. 89001-722, with plate, Cat. No. 250

13、60-046 Furnace, muffle, capable of operation at 900C Oven, capable of operation at 105C Regulator, air, nitrogen, or argon, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson, Model 3122-580 (3122-590 for air) Regulator, oxygen, two-stage, high purity, delivery pressure

14、 range 30-700 kPa (4-100 psi), Matheson, Model 3122-540 Tongs, LECO, Cat. No. 761-929 Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Catalog numbers for consumables used by the LECO instrument are list

15、ed below. For other instruments, see the specific instrument manual for catalog numbers. Quality control (QC) standards, used to check the accuracy of the calibration, can be obtained from LECO or other providers of standard reference materials. Accelerators: Iron Chip HP, LECO, Cat. No. 502-231 Lec

16、ocell II HP, LECO, Cat. No. 502-173 Air, compressed (nitrogen or argon may be substituted), oil and water free, for pneumatics, minimum 50 psi Calcium sulfate, desiccant, Drierite, indicating, 8 mesh, VWR, Cat. No. 22891-040 Calibration and QC Standards: Calcium Carbonate, 12.0% carbon (C) , LECO, C

17、at. No. 501-034 High Temperature Alloy, 0.042% C, LECO, Cat. No. 501-933, Low Alloy Steel, 0.1744% C (Sweden-Jernkontorets), LECO, Cat. No. 501-714 Ore Tailing, 0.25-0.75% C, LECO, Cat. No. 502-318, see Note 1 Ore Tailing, 1.25-1.75% C, LECO, Cat. No. 502-319, see Note 1 3 of 7 703-09 Ore Tailing, 4

18、.25-5.25% C, LECO, Cat. No. 502-320, see Note 1 Tungsten Carbide, 6.00-6.25% C, LECO, Cat. No. 501-123 Crucibles, LECO, Cat. No. 528-018 Halogen trap reagents: Antimony metal, LECO, Cat. No. 769-608 F-Cl Adsorbent, LECO, Cat. No. 769-610 Oxygen, 99.6% minimum purity, extra dry Procedure The analyst

19、is expected to be familiar with general laboratory practices, the technique of combustion analysis, and the equipment being used. Install the analyzer according to the instructions in the manufacturers operating manual. The presence of halogens in the sample has been shown to cause corrosion damage

20、to the instrument, therefore a halogen trap must be used. The LECO system electronics require a two-hour warm up prior to the beginning of operations. Establish operating parameters as recommended by the specific manufacturer. Operating conditions for the LECO analyzer are listed in Table 1. Daily m

21、aintenance must be performed prior to sample analysis according to the manufacturers operating procedure. Accelerators are required when using an induction furnace. Table 1 Operating Parameters for LECO Analyzers Carrier gas oxygen Input pressure 240 kPa (35 psi) 10% Flow rate during analysis 3 L/mi

22、n Pneumatics gas air, nitrogen, or helium Pressure 275 kPa (40 psi) 10% Analysis time Nominal 40 sec Comparator level Nominal value 0.5 Answer precision Nominal value 4 Pre-analyze delay time Nominal value 10 sec Calibration The number of calibration standards to be used is dependent on the concentr

23、ation range to be covered and the linearity of the specific instrument. The calibration and sample analysis procedure for most instruments are similar and follow the steps listed below, but see the specific instrument manual before proceeding. High Carbon Calibration (Carbon Concentration Range 0.2

24、mass-% - 20 mass-% C) Some instruments are capable of multipoint calibration, for example, the LECO CS-600. Other instruments use only single point calibration, for example the LECO C-400 and CS-225. While single point calibration is satisfactory, multipoint calibration should be used where possible

25、. 4 of 7 703-09 Part A- Multipoint Carbon Calibration (LECO CS-600) For LECO CS-600 instrument, it is recommended to calibrate the system using a blank consisting of the accelerators alone and the manufacturers suggested calibration standard(s). 1. Analyze 5 blanks (approximately 1g each of Lecocell

26、 II HP and Iron Chip HP accelerators). The area of the last 3 blanks analyses should agree within 20% (relative). If the area of the last 3 blanks is not within 20%, run 2 additional blanks. If the area of the last 3 blanks is still not within 20% (relative) repeat the maintenance procedure and/or u

27、se a batch of crucibles and accelerators from a different lot. 2. Set the instrument blank value based on the averaged results. 3. Weigh 0.1 and 0.3 g, to the nearest 0.1 mg, of each calibration standard (see Table 2) in duplicate then add approximately 1 g each of Lecocell II HP and Iron Chip HP ac

28、celerators and analyze. Table 2 Recommended Carbon Standards for High and Low Carbon Calibration High Carbon Level, Multipoint/One Point Calibration Calibration Standards Leco Part # Nominal Range, % Carbon Certified Value, % Carbon (Lot number)* Ore Tailing 502-318 0.25-0.75 0.37 0.02 (1006) Ore Ta

29、iling 502-320 4.25-5.25 4.11 0.08 (1003) Tungsten carbide 501-123 6.00-6.25 6.20 0.03 (1024) QC Standards Ore Tailing 502-319 1.25-1.75 1.38 0.04 (1004) Calcium carbonate 501-034 12.0 12.0 (1030) Low Carbon Level Calibration Calibration Standard Leco Part # % Carbon Certified Value, % Carbon (Lot nu

30、mber)* JK-24, Low Alloy Steel 501-714 0.174 0.174 0.001% QC Standard QC-High Temp. Alloy 501-933 0.0421 0.0421 0.0020% ( 1000) *The Certified Value is only for the lot number shown. Certified values may vary significantly, and may even fall outside the listed nominal ranges. Use the Certified Value

31、included with the purchased standard. 4. Select the standard data from the result table and calibrate the instrument according to the manufacturers manual. The Error % calculated during the calibration should be 5%. If not, check the components of the system according to the maintenance procedure an

32、d repeat the calibration procedure. 5. Weigh 0.1 g, to the nearest 0.1 mg, of the Ore Tailing standard (LECO Corp. Cat. No. 502-319, See Table 2) into a crucible, add approximately 1 g each of Iron Chip HP and Lecocell II HP accelerators and analyze. Set this as the drift standard. Drift correction

33、is used to compensate the standard calibration for variation in the instrument hardware that could slightly affect the original calibration. 5 of 7 703-09 Drift standard correction should be replaced in the program every time a drift standard lot is changed. 6. Save the calibration curve in a manner

34、 that identifies high carbon concentration range. 7. Analyze the QC standards to check the accuracy of the calibration using 0.2 g, weighed to the nearest 0.1 mg, of the QC standard (See Table 2) and approximately 1g each of Lecocell II HP and Iron Chip HP accelerators. See Note 2 if the QC carbon v

35、alues are not within the certified value of certificate of analysis. Part B- One Point Carbon Calibration If equivalent instruments, not capable of multipoint high carbon calibration are used, run one point calibration using multiple analysis of the same standard (See Table 1 for LECO instruments).

36、See the manufacturers manual for the specific instrument for guidance. The value of the standard used for calibration must be higher than the anticipated carbon concentration in the sample. Analyze a QC standard to check the accuracy of the calibration (see Step 7 under Part A- Multipoint Carbon Cal

37、ibration). See Note 2 if the QC carbon values are not within the certified value of certificate of analysis. Low Carbon Calibration (Carbon Concentration Range 0.01 mass-% - 0.30 mass-% C) Calibrate the instrument every time samples are analyzed. 1. Preheat the crucibles in the muffle furnace at 900

38、C for a minimum of 1 hour prior to analysis, and then place them in a desiccator to cool to room temperature. Caution: Crucibles are very hot. Use only crucible tongs when removing crucibles from the oven and placing them into a dessicator. If the crucibles are not used within 4 hours they must be b

39、aked again. 2. Analyze 5 blanks (approximately 1 g each of Lecocell II HP and Iron Chip HP accelerators)., The area of the last 3 blanks analyses should agree within 20% (relative). If not, run 2 additional blanks. If the area of the last 3 blanks is still not within 20% (relative), repeat the maint

40、enance procedure and/or use a batch of crucibles and accelerators from a different lot. 3. Set the instrument blank value based on the averaged results. 4. Weigh 0.3 g, to the nearest 0.1 mg, of standard (See Table 2) in triplicate then add approximately 1g each of Lecocell II HP and Iron Chip HP ac

41、celerators and analyze. 5. Select the standard data from the result table and calibrate the instrument according to the manufacturers manual. The Error % calculated during the calibration should be 5%. If not, check the components of the system according to the maintenance and troubleshooting manual

42、 and repeat the calibration procedure. A drift standard is not required because the analyzer is calibrated every time samples are analyzed. 6. Save the calibration in a manner that identifies low carbon concentration range. 7. Analyze a QC standard to check accuracy of the calibration using 0.3 g of

43、 the QC standard (See Table 2) and approximately 1 g each of Lecocell II HP and Iron Chip HP accelerators. See Note 2 if the QC carbon values are not within the certified value on the certificate of analysis. 6 of 7 703-09 Sample Analysis Samples must be uniform in composition. If necessary, grind t

44、he samples using a ball mill to ensure that a representative sample is analyzed. 1. Analyze QC standards prior to sample analysis to ensure the accuracy of the calibration. See Note 2 if the QC carbon values are not within the certified value on the certificate of analysis. 2. Based on the expected

45、carbon level, analyze QC standards and samples on the High Carbon or Low Carbon Calibration program. 3. Use a 0.2-0.3 g sample size for High Carbon Calibration and a 0.3 g sample size for Low Carbon Calibration. Weigh samples to the nearest 0.1 mg. Add approximately 1 g each of Lecocell II HP and Ir

46、on Chip HP accelerators and analyze. 4. Re-analyze the QC standards after 10 to 15 samples. See Note 2. 5. Repeat Steps 3 and 4 until all samples have been analyzed. Notes 1. It is recommended by the manufacturer that Ore Tailing standards are dried in the oven for 1 hour at 105C prior to analysis.

47、2. If analysis of the QC standard does not return the known carbon value within the certified value on the certificate of analysis (or, if there is no range on the certificate of analysis, within the repeatability allowable difference in Precision), determine the cause, clean or repair the instrumen

48、t and begin the analysis sequence again at the calibration point. Only those samples from the previous run not bracketed by QC standard results outside the certified value need to be re-analyzed after the new calibration is performed. Calculations All calculations are performed by the microprocessor

49、 and printed automatically. Report the results to three significant figures above one mass-%, to two significant figures between 0.10 and 0.99 mass-%, and to one significant figure below 0.10 mass-%. Precision Precision statements were determined using UOP Method 999. Repeatability and Site Precision A nested design was carried out for determining the carbon content of three samples with two analysts in one laboratory. Each analyst carried out tests on two separate days, performing two tests on each sample eac