HOW TO MAINTENANCE OF OXYGEN ANALYSER
This Procedure is intended to provide guidance and instructions for carrying out the maintenance of Oxygen Analyzer as per standard practices prescribed by OEM or General Industry best practices in safe manner while ensuring minimization of environmental impacts to the extent possible.
1. Model 1210 Oxygen Probe
2. Oxygen Control Unit (required)
3. Remote Calibration Unit (optional)
4. Span Calibration Gas (typically 20.9% O2 in N2)
5. Zero Calibration Gas (typically 1% O2 in N2)
6. Heater Supply Input to Probe
7. Cell, Thermocouple, and Cold Junction Signals
from Probe
8. Mains Power Supply Input to Control
Unit
9. Signal Outputs/Relays (customer
connections)
10. Automatic Calibration Trigger and
Pressure Signals
11. Mains Power Supply to Remote
Calibration Unit
12. External Mains Isolation Switch
(customer-supplied)
13. Calibration Gas Input to Probe
O2 analyzer is used to measure the percentage of oxygen of boiler flue gas. It is used mostly in the boiler to measure % O2 of boiler flue gas there by knowing the proper fuel combustion in boiler.
GENERAL RESPONSIBILITIES:
All the personnel involved in carrying out /supervising the above activities are required to ensure implementation of this procedure and may consult any other relevant documents indicated under Reference section below.
√ In case the tasks are performed brief the procedure to be followed and environmental and OH&S precautions to be complied by personnel agencies deployed for the above task.
√ In the event of any changes required in the procedure such changes may be requested with Station MR, who would take appropriate action with approval from respective departmental head and Head –O&M.
Job specific responsibilities:
Particulars Responsibility:
1. Issue and Closure of work permit Engineer in charge/ Operation unit & shift in charge.
2. Ensuring isolation Operation shift/unit in charge.
3. Monitoring availability of required tools & tackles and implementation of relevant OH&S and Environmental Procedures Engineer in charge/Supervisors.
4. Checking the Quality of Job and Providing feedback to ensure task Completion as per the procedure Engineer in charge.
5. Performing of tasks in compliance with Instructions and safe working with Equipment Technicians.
6. Carrying out relevant monitoring tasks such measurement, verification and validation to ascertain completion of Scheduled tasks. Engineer in charge.
The following General Safety and Environmental procedure should be ensured.
General Safety procedures:
Safety Helmet must be worn at all times in work place.
Close fitting/protective clothing must be worn at all times in work areas.
Ensure proper physical and Electrical isolations and availability of work permit.
Usage of Ear Plug whenever required
Safety Shoes must be worn at all times in work areas. .
Use Hand gloves if required.
Safety Goggles must be worn in work areas whenever required.
Ensure all flammable materials are safely stored.
Rings & Jewellery must not be worn & Mobiles to be turned Off where it is forebidden.
Long and loose hair must be avoided.
Use Safety Belt whenever required Ensure proper Fire Fighting Devices whenever required
General environmental procedures:
Ensure that there are no spillage and leakages liquids.Store all liquids in secondary containments. Segregate wastes at source ensure their collection,storage and disposal as per procedure for relevant type of waste. If not sure,consult environmental department.
Perfrom activities having emissions/dust geenration in secluded araes in way to contain dust/smoke. Ensure, relevant Common procedure is follwed.
Switch off all lights.equipment and other energy using systems where not required. While working keep in mind what can be reduced-reused and recycled for better environment.
GENERAL INSTRUCTIONS FOR COMPLIANCE:
√ Work permit as should be secured and instructions provided in the permit should be complied. Where instructions are not clear, clarification should be requested from the concerned Supervisior.
√ Work should only be commenced after ensuring that proper work environment is created (ex: Authorizations are secured, Isolations are confirmed, and required mobilization is done.)
√ Access to Emergency evacuation and other emergency services such as medical and Fire protection shall be readily available and contact details are readily available concerned supervisor as well as contactor.
√ Access to drinking water, toilet and other essential infrastructure for both company and contract personnel should be ensured.
WORK INSTRUCTION PROCEDURE:
DETAILS OF HAZARD INVOLVED
a. Electric Shock.
b. Fire
c. Injury due to improper handling of Equipment
d. Exposer to heat
e. Exposer to flue gas
SAFETY PRECAUTION REQUIRED:
a. Use hand gloves while working with the system.
b. Ensure proper illumination.
c. Use dust mask & safety goggles while cleaning the panels.
d. Keep the fire extinguishers (CO2 cylinders) ready with reachable limit for any exigency.
e. Permit Type: Permit to Work Order.
f. To confirm for necessary isolations before starting the work
g. Permit Approving Authority: Shift in-charge (Main Control Room)
T&P INCLUDING SPECIAL ONES:
a. Multi meter
b. Insulated General tools.
c. Panel key
d. Marking cloth and soft cotton cloth
e. Span calibration gas (within the range 10 to 21% O2 in N2)
f. Zero calibration gas (within the range 0.1 to 10% O2 in N2)
4.3.4 SPARES & CONSUMABLES
a. Marking cloth
b. Teflon Tape
STANDARD MAINTENANCE PROCEDURE:
a. Check the tightness of all cable terminations & tube fittings.
b. Remove the Probe from tapping point, Put a blank for Tapping Point & check for the following:
I. Check the Ceramic Filter & clean it. If there is some damage or fully contaminated then replace it.
II. Check for the Cell Resistance if it is >1200 Ohms then replace it.
c. Then Re-insert the probe to the duct.
d. Check for the Calibration Gas Supply Pressure. If it falls below the specified pressure then change the Cylinder.
e. Check the pipes & replace it if found some damage.
IN-SITU PROBE TESTING AND CHECKING:
In-situ checking will assist with identifying errors or faults associated with the probe. Cell output voltage can be displayed on the user interface using the Diagnostics menu as an alternative to the following manual checks. After any corrections the system must be fully calibrated.
Ensure that the flue temperature is within the limits 20 °C to 600 ° and allow a 20-minute warm-up period for the probe.
a. Remove the blanking plug from the calibration gas inlet and fit the pipe, nut and olive from the connector kit to the inlet.
b. Connect the calibration gas using flexible tubing to fit the outside diameter of the pipe ( ¼” o.d.).
c. Apply the test gas at a rate of 2 ltr./min and allow 5 minutes for the analyzer reading to settle.
If the analyzer response is normal when measuring calibration gas, but sluggish and insensitive when measuring flue gas, then replace the ceramic filter.
If you cannot obtain the correct calibration gas response, measure the cell output voltage detailed in the Step d.
d. With the calibration gas connected, display the EMF of the cell by selecting CELL from the Diagnostics menu.
The measured voltage should correspond generally to the oxygen volume percentage in the calibration gas used. Slight differences may results, if the probe’s cell constant is not zero.
If there is a difference of more than ±5mV between the measured cell output voltage and the characteristic curve, check the probe heater temperature by measuring the thermocouple voltage as described in the following Steps e and f.
e. Using either a mercury or digital-type thermometer, measure the ambient temperature in close proximity to the Probe T/C connections at the head of the probe.
f. Measure the voltage across the thermocouple (T/C) contacts at the probe.
If the thermocouple voltage is correct as compared to the ambient temperature, remove the probe from the flue gas and replace the cell.
If there is no thermocouple voltage proceed to Step (f.) If the thermocouple voltage is low proceed to Step (g.)
g. Disconnect the thermocouple leads from the thermocouple (TC) terminals and check the thermocouple for open or short circuit.
If the thermocouple appears to be faulty, replace the probe insert (including thermocouple and heater assembly). If the thermocouple appears to be in order continue from Step h.
h. Switch off the power supply, disconnect the heater leads from their terminals on the User Interface, and measure the resistance across these leads at the probe terminal head and at the cable ends.
The correct heater resistance is approximately 200 Ω.
If the resistance is not correct, check the heater wiring, and if necessary, replace the probe insert (including thermocouple and heater assembly).
CHECKS BEFORE RELEASE OF PERMIT:
a. All T & P’s and manpower are removed.
b. Clean the maintenance area properly.
c. Normalize all isolation & Return PTW
HANDLING OF CONCESSIONS OR DEVIATIONS:
a. In the Event of Any Changes or Deviation from Procedure are required due to Urgent business requirements or system/Equipment approval should be obtained from Head O&M.
b. The report for the concerned task should clearly Captured the details of deviations and reason for the same.
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