INNOVATIVE TOOLS AND TECHNIQUES And NEW O&M PRACTICES

1. INNOVATIVE TOOLS AND TECHNIQUES And NEW O&M PRACTICES By : Supratik Mukherji, Chandra Sekhar Goswami, Vijay Kumar

2. CONSTRAINTS OF OPERATION PART - I

3. Problem 1 – The Control System • Since 1995 the controlling of the main plant was through a Control panel which was supplied by BHEL. • Constantly two Control room engineers had to go back and forth and left to right controlling the process parameter at the Control desk which had buttons. • All the time they were on their toes throughout the entire 8 hour of duty shift, with hardly any time for relaxation or attending personal needs.

4. Control System – Modified • This was converted into DCS (Distributed Control System) of Honey-well and Max DNA for efficient operational control. • This technology upgradation allowed the control engineer to operate the entire plant through the HMI (Human Machine interface) itself without operating the Control panel buttons • At the touch of a screen and changing multiple screens the operator had access to the system as well as operating conditions.

5. Problem 2 - Data Information Transparency There were no systems that would ensure that others across the plant as well as at the Corporate Office in Mumbai could view the plant operational online data except those who were available in the control room. The Concept of Central Monitoring system could not be implemented by the Corporate monitoring teams.

6. Problem 2 - Data Information Transparency With the introduction of the Pie Server, E-Logbook, SAP all concerned managers across the company even in far off locations like Corporate centres in Delhi and Mumbai could view the process data online as and when required ensuring fastest communication and better Control and transparency across all divisions

7. Problem 3 - Maintenance systems • Since beginning, the maintenance philosophy was Breakdown Maintenance and Preventive Maintenance as per the directives of the OEM, BHEL. • For that we had to call people from BHEL during the outage period charging hefty fees and other facilities from us. • We had no real clue as to what was happening to the machine and its condition over time.

8. Problem 3 - Maintenance systems • We started with CBM (Condition-Based Maintenance) by which defect notification level drastically reduced . • Some of the methods adopted were :- • Oil sampling analysis, • Thermography, • Signature analysis, • Other techniques like sonography, etc

9. Problem 4 - Grid Isolation Voltage generated at 11KV is stepped up to 132 KV for transmission to Golmuri substation At Golmuri it enters the Tata Steel premises. Also at Golmuri sub-station the DVC lines enter and thereafter goes to the Tata Steel grid. Due to the constraint in the operating system logic, every time the DVC grid would fail due to some Line fault , CT Burst , etc the high frequency generated would trip the Tata Power units as well. Tata Steel our customer was not happy with this situation.

10. Problem 4 - Grid Isolation We introduced DVC-isolation logic 2 years back, that was an in-house technology after brainstorming by our engineers along with BHEL designers and electronic experts and saved many unplanned outages during DVC isolation. This effort was appreciated by CEO & MD, Tata Steel, our only customer.

11. Problem 5 - Stack Emission • Earlier the stack emission (SPM level), permissible limits were 150 mg/NM3, • As years and decades passed, the pollution norms became stricter and also reduced and is today at 50 mg/NM3. • A constant plume of white smoke was an eyesore for anyone who would visit the plant and every time Ammonia dosing proved to be very costly as per the original design.

12. Problem 5 - Stack Emission • In collaboration with General Electric, this was discussed and they offered a solution of a third pass in the ESP. • This third pass was installed a year back recently in addition to the earlier ones. • This has drastically brought down the SPM to within acceptable limits. • Further modification expected to come in 2021 will be the installation of the FGD unit

13. Problem 6 - Coal Mill Rolls • The Ni Hard coal mills’ rolls were having rolls that used to fail frequently, thus challenging the plant reliability. • The mills could not be loaded as desired and the throughput of the mills was much less than normal wear throughout as per OEM • The mill fineness was also under severe stress and not as per recommendation. • Every 3 months mills had to be taken down for maintenance adding to downtime.

14. Problem 6 - Coal Mill Rolls • This concern was addressed in the coal mills by replacing the rolls by HPMS rolls - SINTERCAST • These have long life and reliability. • Grinding element life increased from 3 months to almost 24 months. • Mill loading improved to 80% of its design capacity with different coal. • Frequency of ring roll settings reduced as erosion rate is reduced due to sinter cast ceramic elements. • Collar formation in grinding element is less comparatively to conventional grinding roll .

15. Problem -7 CT Fan and Aux Power • The original CT fans were supplied by Paharpur when the plant was set up and were heavy. • They used to draw high current while on operation • This caused high operating current and eventually higher Auxillary power consumption. Which was a waste

16. Problem -7 CT Fan and Aux Power • Fan blades were replaced by light weight and yet strong FRP blades • Advantages are:- • Less Start-Up Torque and Reduce Load on Drive System • Lesser current • Low Weight, High Strength, Low Surface Deflection and Deformation • Impact Damage Protection and Precise Blade Placement • No Joint Line Delamination and Splitting • Prevents Debris and Moisture Entry into Fan Blade Cavity

17. Problem 8 - Air Compressor and Aux Power • The Centac air-compressors (Make: Ingersoll Rand) were operated manually by field engineers • This resulted in unreliable supply of both instrument air (very critical during oil firing in the Boiler) and service air at times. • There was extra unloaded running of compressors leading to overall Auxillary Power loss which was a waste

18. Problem 8 - Air Compressor and Aux Power • CEM (Centac Energy Management) System was introduced. • This is automatic and is operated from control room, • It ensures reduction of auxiliary power consumption as compressor modulation, loading / unloading are done automatically as per process demand.

19. A BREAKTHROUGH WITH RELIABILITY CENTERED MAINTENANCE (RCM) PART - II

20. Maintenance Philosophy in ageing plant • Tata Power Jojobera, Jamshedpur Unit # 1 is approaching towards 25 years. In initial years, maintenance process mainly organized with the following process - • Routine Preventive maintenance, • Breakdown Maintenance • Major Overhauling • These maintenance process & planning mainly was guided & driven by – • OEM guide lines • Statistical data • Experience • Later Condition based Maintenance (CBM) was introduced to assess & enhance the life of the Equipment..

21. Maintenance Philosophy in ageing plant • Requirement for CBM • Maintenance philosophy changes with the changes of the business requirements, customer need, effectiveness & cost. CBM came into picture along with Preventive Routine Maintenance, Major Overhauling & to minimize Break Down Maintenance. CBM has introduced to mitigate the following criterion - • Cost of Failure became higher • Customer demands gradually switchover from Cost to Cost with Reliability • Competitive business scenario • Availability of New Technology for Condition Assessment • Cheaper Cost of New Technology for CBM • Availability of Skilled Manpower • To increase Effectiveness of the Equipment

22. Maintenance Philosophy in ageing plant Steps of Failure & it’s Costs Point where Failure start to occurs Point where we can find out that – it is Failing (Potential Failure) Early Signage Audible Noise P Hot to Touch Equipment Condition Point where it Fails (Functional Failure) P – F Intervals F Time Cost of Restoration

23. Maintenance Philosophy in ageing plant • CBM Task Applicability and Effectiveness : • The following considerations must be made for a condition-monitoring maintenance task to be considered applicable and effective. • Onset of failure must be detectable: • There must be some measurable parameter that can detect the deterioration in the equipment’s condition. • In addition, maintenance personnel must be able to establish limits to determine when corrective action is needed. • Practical interval in which condition-monitoring tasks can be performed: • The P-F interval must be sufficient to permit a practical task interval. For example, a failure with a P-F interval of minutes or hours is probably not a good candidate for a condition-monitoring maintenance task.

24. Maintenance Philosophy in ageing plant 3. Sufficient warning so that corrective actions can be implemented: The PF interval must be long enough to allow corrective actions to be implemented. This can be determined by subtracting the task interval from the expected P-F interval and then judging whether sufficient time remains to take necessary corrective actions. 4. Reduces the probability of failure (and therefore the risk) to an acceptable level. The tasks must be carried out at an interval so that the probability of failure allows an acceptable risk level to be achieved. Agreed upon risk acceptance criteria should be determined and recorded. 5. Must be cost-effective. The cost of undertaking a task over a period of time should be less than the total cost of the consequences of failure.

25. Maintenance Philosophy in ageing plant Effectiveness of CBM: Notification of Defects drastically came down after introduction of CBM

26. Transformation of Maintenance Philosophy in ageing plant • Maintenance strategy: • Corrective / Reactive – Fix & based on failure • Preventive – Maintain on predefine schedule • Predictive – Maintain when condition detected • Reliability Centered – Strategy based upon the role of the asset, safety and criticality. • Reliability Centred Maintenance(RCM) is a major transformation initiative undertaken by Tata Power aimed to enhance Operational and Maintenance Excellence which is an important imperative for a long-term successful Operating Model.

27. Transformation of Maintenance Philosophy in ageing plant Having achieved a higher standard of maintenance practice, maintenance philosophy eventually tuned towards reliability with benchmarking as a Tool for improvement & established standards.

28. Transformation of Maintenance Philosophy in ageing plant • Why RCM Introduced: • RCM introduced to Optimize the Maintenance processes with the support of IT & Digitization. • RCM is aimed at creating a forward looking and highly capable O&M organisation, in-depth understanding of assets. • Tracking of assets in component level & thereby optimising maintenance work, maintenance costs and improving the availability and reliability of assets. • To create appropriate forums for enhancement of institutional knowledge & learning to adopt the program a sustainable model for success. • Structured data capturing (capturing maintenance history at the right levels), standardization of data, analysis of the data in the component level are the most basic elements for Reliability Centered Maintenance (RCM). • After getting higher standard of maintenance practice, maintenance philosophy tuned towards highest level of reliability and benchmarking.

29. Transformation of Maintenance Philosophy in ageing plant Key Drivers for Introduction of RCM in Tata Power

30. Transformation of Maintenance Philosophy in ageing plant The steps involve to create RCM environment are as follows- Identification of Assets & divided into common and unitized areas (functional locations) Each unit is then segregated into discrete functional locations such as steam generator & auxiliaries, turbine & auxiliaries, generator, electrical system etc. These can further be divided into sub-functional locations. For example, Unit Level Functional Location, e.g. "Steam Generator and Auxiliaries" can be divided into coal firing system, primary air system, secondary air system etc. Coal firing system (at the next level) comprises of distinct systems such as milling systems (for each bunker-feeder-pulveriser combination), seal air fan system and process instrumentation. It is to be noted that each functional location can have equipment directly installed, in addition to sub -functional locations. For example, equipment such as bunker, mill, feeder which cater to the primary functionality of the milling system are directly installed in it.

31. Transformation of Maintenance Philosophy in ageing plant Standardization of Functional Location & prepare Team  After identification of functional location, compare it with other division to create unique functional location & sub-functional location according to their hierarchy. Create a related manpower pull for the similar functions across the division. Prepare the team as maker & create another team of different functions for checker & approver of all the functions. Equipment creation, hierarchy definition & standardization of equipments & component Under the functional locations prepared equipments (some of the already was in the system & others prepared for in detail analysis). Equipment hierarchy prepared from the concept of parent & child equipments. Again, equipments subdivided into component level to track & optimize in component level (like rubber O-ring, coupling bolt, copper washer etc.)

32. Transformation of Maintenance Philosophy in ageing plant Standardization of data for failure mode, cause code, activity Preparation of unique failure mode, cause codes & activities for similar nature of defects & actions for proper analysis as well as preparation historical data bank. It requires huge task of data alignment & data cleansing from the history of the existing software (SAP PM & MM module). FMEA Creation Exhaustive Failure Mode Effect Analysis (FMEA) creation is the next part of the process. This FMEA preparation require some Designer’s involvement, expertise opinion, Institutional knowledge, knowledge on benchmark & working experience. To bridge all these things some training requires to provide for all segments of FMEA. This exhaustive FMEA consists of the following –

33. Transformation of Maintenance Philosophy in ageing plant • FMEA Constituents • Name & code of the object, function & functional failure of the object. • b. Failure mode, cause of failure, problem code, effect of failure, failure pattern & interval, cost of failure for supply, services & business loss. • c. Impact of failure on equipment, Plant, System, immediate & overall effect. • d. Root cause analysis in details. • e. Calculation of RPN number based on Severity, probability, detection rating & preparation of process control mechanism. After that preparation of action item, again calculation of RPN number based on new action item.

34. Transformation of Maintenance Philosophy in ageing plant Part of FMEA

35. Transformation of Maintenance Philosophy in ageing plant Data entry after all cross verification & analysis with the help of Software. After validation of input data, need to upload in new Software. Need to careful before uploading or data entry as garbage in will result to garbage out. Tailor made analysis can be extracted in form of report. This part of the activity utilized IT supports & digitization. Creation of Optimize Maintenance policy This analysis report will derive to create Optimize Maintenance policy.

36. Transformation of Maintenance Philosophy in ageing plant Tools for RCM Data Entry & Tailor-made Dashboard preparation

37. Transformation of Maintenance Philosophy in ageing plant Dashboard for Coal Mill

38. Transformation of Maintenance Philosophy in ageing plant Dashboard for Entire Equipments

39. INCREASING EFFICIENCYTHE 6 SIGMA WAY PART - III

40. This gap leads to a loss in Heat Rate of 18.54 Kcal / KWH and we lose 1.31 Crores @ Rs. 1154/MKcal. OUTPUT SUPPLIER Coal DM Water Availability of Machine PROCESS Carry coal to Mill Coal Mill Operation Combustion of coal Heat Pick-up in Boiler Flue gas exit at ESP 1.FGET 2. LOI 3. CO percentage Coal Handling Plant DM Plant Maintenance TATA Steel INPUT CUSTOMER S I P O C TABLE

41. DEFINE Anderson Darling Test p > 0.05 stating distribution was normal Quick Wins Identification: 41

42. MEASURE Potential Root Causes (X’s) Outcome (Y) High FGET OUTPUT INDICATORS INPUT INDICATORS • Air Flow In Furnace • Burner Tilt • DT across FSH • DT across LTSH • DT across ECO • DT across RAPH • Bottom Ash LOI • Coal Mill Fineness • Volatile Matter / Fixed Carbon Ratio • Conductivity of DM Water • Availability of suitable Coal Mills PROCESS INDICATORS • High FGET • Suspended particulate matter (SPM) • LOI After Quick Win Implementation Cpk = -0.58 Sigma Value= -0.24 Fish Bone Diagram to find out root cause

43. ANALYZE Using Minitab 17 Note : Fit regression menu – select responses and continuous predictors Fit Regression Model ------ Select Responses and Continuous Predictors (except mentioned three variables) ----- Select Graphs -------Residual plot as Deleted and Four in one Regression ------ Best Subset ------ select all as given (except DT across RH) Outliers HIGH VIF

44. ANALYZE Average FGET = 176.13 + 0.1299 Air Flow - 0.03952 Burner Tilt - 1.199 Fly Ash LOI + 0.00728 DT Across FSH  -0.04565 DT Across LTSH + 0.3310  DT Across Eco - 0.8135 DT APH Comparing Performance Guaranteed Test (PG Test) value we have concluded that the following contributors are responsible for higher FGET on priority basis. 83.07%) Delta Temperature across APH High Burner Tilt Delta Temperature across LTSH Delta temperature across FSH

45. ANALYZE Analysis of each valid cause SAMPLE High DELTA T across APH

46. IMPROVE SAMPLE

47. IMPROVE Improve phase has been carried out during the Annual Shutdown of Unit and following major jobs done along with others • After implementing all the mentioned points Flue Gas Exit Temperature has almost reached to its desired value • Detail of Expenditure During Improve Phase Implementation: • APH Seal assembly, heating element and others associated work costs Rs. 41,07,612.62

48. IMPROVE SAMPLE BEFORE AFTER All air gaps repaired by replacing ropes or body welding , etc. All damaged refractory replaced. Economiser outlet bellow repaired and packed with kao wool to prevent leakages/ air ingress.

49. IMPROVE Tangible Results Process Capability Keeps on improving in every steps Beginning of Analyze Phase End of Improve Phase At the Beginning of the Project CPk = 0 Sigma Value= 1.5 CPk = 0.06 Sigma Value= 1.68 CPk = -1.39 Sigma Value= -2.67 CPk = -0.6 Sigma Value= -0.3 Beginning of Measure Phase

50. CONTROL • After getting the desired value to control the process within its limit following standards has been made as a recommendation: • Periodic soot blowing in APH and Boiler (for boiler once in a week and for APH twice in a day) • Calibration of temperature elements on opportunity basis • Burner tilt auto calibration implemented by installing electro-pneumatic controller. Burner tilt to be maintained in accordance with flow to Boiler Re-heater and super-heater zone. • Top elevation coal mill to be run with lower GCV (Gross Calorific Value) coal. • A process Quality Audit carried out to ensure the healthiness of all parameters.