Carbon On Catalyst By LECO Analyzer Flashcards
Preparation of apparatus
•turn on air and oxygen to instrument using 1/4 turn valves located in each side of instrument
•if pedestal not lowered, lower using pedestal button
1. With pedestal lowered, check Auto-Cleaner assembly by removing pneumatic lines
2. Lift the lock washer and twist the cleaning head counterclockwise while pulling up
3. Remove dust filter from dust filter assembly
4. Wipe clean top and interior of dust filter (sonicate if necessary)
5. Remove dust and soot from cleaning head. Inspect tip to verify it is open. If clogged, open using lance cleaning brush
6. Inspect and lightly grease o-ring on cleaning head. Replace if necessary
7. Remove o-rings from dust filter, clean, lightly grease and place on clean filter and place filter back jn assembly
8. Reinstall cleaning head by aligning marks on head, lowering lock washer and rotating head clockwise
Clean combustion tube
- In software, select instrument and maintenance. From new screen select general maintenance . Verify lock button on action bar is not active
- Execute Step 1 and remove pedestal when lowered (assume pedestal is hot)
- Execute Step 2 to automatically lower combustion tube.
- Ensure tube is not hot, then remove combustion tube from cup assembly
- Disassemble combustion tube assembly by loosening plastics lock but and gently pulling glass tube from base
- Clean and inspect combustion tube. Replace tube if it is cracked or badly scored
- Inspect o-rings (one on top of base and one underneath base) and replace if cracked or worn. Lightly grease o-rings with vacuum grease
- Install plastics lock but and tighten to lock combustion tube into place. Do not over tighten
- Place combustion tube assembly on lower cup assembly making sure it is seated firmly against work surface
- Verify lock button on action bar not active
- Execute Step 3 to raise and lock combustion tube in place
- Replace pedestal when cup assembly lowers
- Turn on gas
- Execute step 4 and perform leak check. Verify instrument passes. If not, troubleshoot and perform another leak check
•once leak check passed. Perform system check by selecting diagnostics (allow instrument 30 minutes to warmup)
•from top tabs select System Check. Press Start button on lower right screen
•troubleshoot and resolve any items that failed System Check
Analyzing Blanks, Standards, and Samples
To analyze sample, sample information is logged in using software. Sample type and information associated with it must be entered
•a sample set consists of sample name, number of repetitions, description, method and average results
•sample repetitions consists of mass, comments, and sample results
Analyzing a Blank: run at least 2 blanks
1. Enter number of reps for Blank set by adjusting + or - buttons on Login bar
2. Select Blank on login bar
3. Select method and then select method name from list:
A. The high method is designed for Carbon Concentration Range of 0.2 mass % to 20 mass %
B. The Low method is designed for Carbon ConcentrationRange of 0.01 mass % to 0.30 mass %
4. All Blanks automatically have mass of 1.0000g (cannot be edited)
5. Add 1 scoop each of Lecocell II HP and Iron Chip HP accelerators
6. Place 10mm lid on crucible with flat side facing up
7. Using tongs, place crucible in pedestal
8. Select LECO button to begin analysis
9. At end of analysis, wt% carbon will be displayed on screen on the Reps line. The average of duplicates will appear on Set line.
10. LECO will run filter cleaning cycle after each run. Pedestal will lower for al but last sample. If needed, touch pedestal button to lower glowing hot crucible. Using tongs, carefully remove crucible from pedestal and place it in attached waste container.
Analyzing a standard
Run QC in duplicate. DO NOT add Iron Chip Accelerator to standard. Adding iron chips to standard or sample that is magnetic will cause furnace to heat up to temperatures high enough to damage O-rings
1. Run same as Blanks, however weight the standard by placing crucible on scale, taring and adding standard to crucible. Also, only add Lecocell II HP to crucible with standard.
Analyzing Sample
Run sample in duplicate.
1. Perform Steps 1-12 for analyzing Blank except select sample from login bar
Shutting down Instrument
- When all analyses complete, lower pedestal and remove crucible
- Raise the pedestal. Make sure pedestal is in up position
- Select session Tab at top center
- Select Exit Gas Off
- Turn off oxygen and air using 1/4 turn valves
Troubleshooting and maintenance
LECO C744 Carbon analyzer tracks maintenance activities in timeline using Counters.
• if counter timeline exceeded, maintenance will have to be performed as indicated and acknowledged
•software will generate a sign to indicate a problem. Once problem is resolved sign will disappear
•after performing maintenance, select Perform button from action bar. If no maintenance necessary, select inspect button. Both buttons will clear.
Once issue is resolved it is recommended that you perform a leak check and system check to verify instrument is fit to use.
Purpose
Determine total carbon on FCCU catalyst using a LECO Carbon analyzer. Excessive carbon can shorten life of catalyst and render catalyst either more or less reactive
