Sandeep Pillai, PENTA India Technical Consultants Pvt. Ltd
Lab. Instruments find it?s use not only in routine quality check in the plant but number of portable lab. instruments are widely used in diagnostic studies. Sandeep Pillai of PENTA India Technical Consultants Pvt. Ltd. updates the readers on the subject.
Why process audits are done,Can you just list down various lab Instruments you are using during the process audit of a cement plant.
Plant audits are basically done to know about the plant operation, equipment condition status which helps in plant optimization and minimisation of specific electrical/Thermal energy. Process audits in a larger extent helps in enhancing the productivity and minimising energy consumption. It also requires the use of various portable instruments, values of which prove to be vital for the audits. Major part of the data collection in field is done through various instruments Some of them have been listed below.
Refer to Table 1.
During the various process audits what all gas measurement you do? Depending upon the area of the cement plant like the kiln inlet, pre-calciner, pre heater, coal mill silos and so on we need to monitor CO, CO2, O2, NOx, SOx, are to be monitored.
Please provide information on the latest generation of laboratory Instruments you rely on apart from what is stated above.
Apart from field measurement, laboratory analysis play a vital role while carrying on the technical audit. Some of them are mentioned in Table 2.
Which are different instruments available for measurements?
Cement plants are generally low pressure (draft), high temperature ,high flow, dust process in which the continuous monitoring of various parameters are required. Pressure ,temperature, flow load, level and so on being the important ones. Pressure transmitters, differential pressure transmitters, level transmitters, pressure gauges, flow meters, Ultrasonic or radar type level transmitters(non contact type), Nucleonic level for pre heater cyclones are most generally used by cement customers. Ingress Protection class of 66, 67 and 68 are of utmost importance
Why calibration of these instruments is required?
Calibration defines the accuracy and quality of measurements recorded using a piece of equipment. Over time there is a tendency for results and accuracy to drift particularly when using particular technologies or measuring particular parameters such as pressure ,temperature and so on. To be confident in the results being measured there is an ongoing need to service and maintain the calibration of equipment throughout its lifetime for reliable, accurate and repeatable measurements. The goal of calibration is to minimise any measurement uncertainty by ensuring the accuracy of test equipment. Calibration quantifies and controls errors or uncertainties within measurement processes to an acceptable level.
How you make sure that the results given by various measuring instruments are correct and dependable?
The primary criteria of evaluation in any measurement or observation are:
Validity comes from Cross verifying with alternate devices and analog gauges by directly placing them it in the field and checking the readings and also cross verifying through theoretical tables of measured readings. Also material test certificates, suppliers own calibration reports are also needed for cross checking and verifying. Reliability refers to a condition where a measurement process is consistent over repeated measurements.
What is the variation, the portable instruments show from place to place?
There won?t be much variation apart from deviation limit/ error % based on measuring range due to the pressure changes at different altitudes and ambient temperature variations.
Locations in cement plant where the energy audit is more focussed on?
The energy audits are basically done by BEE Accredited and Certified Energy Auditors and Managers.
Energy audit involves the process of detailed examination of the existing energy, measurement and analysis of demand and power factor, Heat balance and Air balance, analysis of specific power consumption and so on.
Energy audit being done is focussed on the following areas of cement plant
- Power distribution system
- Kiln System (Kiln, Pre-heater, Grate Cooler and Process fans)
- Grinding Mills Circuits (Raw Mill, Coal Mill, Cement Mill and Fans)
- Compressed air system and Roots Blowers.
- Bag Filter and Circulation Fans
- Cooling water system and Pumps
- Crusher, Bucket Elevators, Belt Conveyors
- Lighting system
Apart from the instruments mentioned above, power analyser, lux meters etc play a vital role during audit.
In case if you happen to use the instruments from the client, what are your expectations about the dependability of the instruments?
Device should be compatible with calibrating instrument, Instrument shall have enough capability to source/measure the process device requirements (like range of measurement, device protocol which can communicate with instrument). Test certificates, calibration reports are also verified.
Table 1: Commonly used portable laB. instruments
- U Tube Manometer/Digital manometer
- Inclined Tube Manometer
- Portable gas analysers (CO,CO2,O2, NOx)
- Portable temperature detectors
- Vane Anemometer
- Pitot tube (S type and L type).
- Tachometer.
- Measuring tape
- Tong tester
- Radiation pyrometer
- Dust emission measuring kit.
- High volume gas sampler.
Table 2:
- Stationery lab.
- Instruments XRF-Basically used for the elemental analysis
- XRD-Phase quantification.
- Bomb calorimeter-for gross calorific content
- Automatic blaine apparatus
- Inverted reflected type microscope
- Orsat
- Free lime analyser
- Online analyser such as cross belt analyser.