THE DESIGN, EVALUATION AND MONITORING OF AN EFFECTIVE PREVENTIVE MAINTENANCE (PM) AND LUBRICATION PROGRAMS FOR ROTATING EQUIPMENT IN NATIONAL FERTILIZER COMPANY OF NIGERIA (NAFCON) A CHEMICAL PROCESS PLANT USING PLANTS AND INSTRUMENT AIR COMPRESSOR AND PALLETIZER INFEED CONVEYOR AS CASE STUDIES

THE DESIGN, EVALUATION AND MONITORING OF AN EFFECTIVE PREVENTIVE MAINTENANCE (PM) AND LUBRICATION PROGRAMS FOR ROTATING EQUIPMENT IN NATIONAL FERTILIZER COMPANY OF NIGERIA (NAFCON) A CHEMICAL PROCESS PLANT USING PLANTS AND INSTRUMENT AIR COMPRESSOR AND PALLETIZER INFEED CONVEYOR AS CASE STUDIES

INTRODUCTION

The National Fertilizer Company of Nigeria (NAFCON) Limited, Onne was a chemical process plant established in 1987 with a statutory function of producing various brands of fertilizers. It was a company policy to maintaining continuity of plant operation at the lowest possible cost, through the provision of total equipment reliability and prevention of equipment failures based on the philosophy of “ if it works, don’t fix it”, but inspect and monitor it at prescribed frequencies and repair only as indicated by Equipment Condition Monitoring (ECM) program. If fixing is required, “fix it right the first time; should equipment failure occur, perform a complete “Root Cause Failure Analysis”.

The first defense against chronic equipment failure is an effective Preventive Maintenance (PM) program, which includes proper and periodic lubrication of rotating equipment in all the plants. The period of eight years that I worked in NAFCON as a Preventive Maintenance Engineer, it was part of my responsibilities to design, monitor and evaluate the implementation of PM programs. In this report, I highlighted the various stages involved in the design of an effective preventive maintenance program for Plant and Instrument Air Compressor, 2004-J/JA in Utility Plant. This equipment was very critical rotating equipment for the daily operations, maintenance and safety of the entire plant complex     

Justifying a change to PM program

Stage 1: In NAFCON the decision to design PM program for the Plant and Instrument Air Compressor, 2004-J/JA started with the understanding of the importance of the equipment towards production. The Preventive Maintenance Unit liaised with operations to draw a decision flow chart, presenting major questions to be addressed as shown in Fig. 1  

Stage 2: Plants Equipment Survey

Plants equipment survey were undertaken to identify the locations of the equipment in the various plants, namely, Ammonia Plant, Urea Plant, NPK Plant, Bulk Blending Plant and Utilities Plant. The survey enabled us to collect some vital information about the rotating equipment such as general data and equipment technical data.

Equipment general data comprised of the following:

Identification            -     ID Number, (2004-J/JA)

-          Description (Plant and Instrument Air Compressor)

-          Manufacturer and Vendor

-          Year of Manufacture

-          Location and System details

Technical data           -    Engineering drawings

-          Specification references

-          Parts description

Purchase                    -    Date of purchase

-          Vendor

-          Purchase order number

-          Price

Installation date        -     Engineering contractor

-          Date

Equipment data or nameplate tracking program were developed for all rotating equipment from the general data; and were stored in our Computer Maintenance Management System (CMMS). This becomes very useful in inventory control database of the entire plants; which were made available upon request.   

Stage 3: Examining the recommended maintenance advice by the manufacturer

Most of the rotating equipment came with operation and maintenance manuals. In these manuals the manufacturers recommended some calendar-based maintenance schedule to avoid deterioration due to prolonged intervals between servicing and re lubrication.

In the course of the Plant Equipment Survey, we were able to identify the operating conditions or environment of the Plant and Instrument Air Compressor, 2004-J/JA. These made me to make further addition to the recommended maintenance advice by the manufacturer; thus designed a comprehensive PM program for the equipment as shown in Form-A:

  

Plant: Utilities                                                                                         Date:…………………… 2004-J/JA: Plant and Instrument Air Compressor
Period	PM Tasks	Remarks
Daily:
	Check air leaks
	Repair air leaks
	Check couplings
	Repair faulty couplings
Weekly:
	Lubricate air pump
	Check oil levels, leaks and that manhole is secure
	Drain off moisture traps
	Drain manual airline filters
	Top up airline oil lubricator
	Check crankcase oil level and fill to overflow
	Drain receiver
2-Monthly
	Check crankcase oil
	Tighten all bolts
	Inspect, clean and lubricate sleeve bearing electric motor
3-Monthly
	Inspect and clean air intake elements
	Inspect and clean compressor valves
	Clean all external surfaces
6-Monthly
	Inspect, clean and lubricate ball bearing electric motor
	Inspect and if necessary adjust belts for tension and wear
Utilities Operation Supt:                                                      Date: ……………………   Area Maintenance Supt:                                                       Date: ……………………

                      

                   Form-A: PM checklist for 2004-J/JA, Plant and Instrument Air Compressor

This format was adopted in the design of Preventive Maintenance (PM) program for other rotating equipment in the Plants. They were compiled and installed in our computer.

Stage 4: Computerization of PM program

NAFCON was a complex made up of the following Plants:

1)      Ammonia

2)      Urea Melt

3)      Urea Granulation

4)      Utilities

5)      NPK

6)      Bulk Blending Plant

7)      Bagging

Each of the Plants had rotating equipment, Fans, Blowers, Pumps, Compressors, Generating Sets, Turbines, etc. Their PM programs were scheduled yearly and written in the ECM/PM unit computer, using LOTUS 123 software. Every week, equipment scheduled for PM checks were printed and sent to the Plant Maintenance personnel for execution. The maintenance personnel liaise with operation personnel to make ready the equipment for their PM checks to be carried. Upon completion and duly signed were sent back to the PM Engineer, who ensured that they were fully implemented.

PM Monitoring and Evaluation Program

To ensure that the scheduled PM program sent to the Plants were effectively implemented, we carried out routine visual inspections of rotating equipment facilities and had regular meetings with Plants Operations Personnel. At the end of the meeting, departments that were unable to execute their PM programs due to Plants operations were rescheduled. Every quarter from the executed PM checklists/program received from the various Plants Maintenance Departments, their level of compliance was presented in the form of bar-chart; thus indicating the level of execution of the PM program within the period.

                   

         

THE DESIGN OF LUBRICATION PROGRAM FOR ROTATING EQUIPMENT IN NAFCON

Lubrication is another important aspect of Preventive Maintenance schedule, my experience in NAFCON showed that about 60 percent of rotating equipment problem can be prevented or solved with an appropriate lubrication program.

This report contains procedures taken by PM Unit to design and implement an effective lubrication program for rotating equipment in NAFCON.

Stage 1: Equipment Survey

a) In other to establish a Plant-Wide lubrication program, the PM Unit surveyed each piece of rotating equipment, noting the manufacturers’ recommendation and warranty provisions for lubrication along with the equipment condition, such as:

       I.            Operating speed

    II.            Loads

Operating conditions, such as:

       I.            Contaminants

    II.            Temperature

 III.            Equipment history

This information guided us in designing a suitable lubrication and maintenance program, Scheduled oil change intervals and routes to perform the actual lubrication tasks.

b) We obtained similar information for each sub-component of the rotating equipment, such as drive motor, gear couplings and bearings.

c) Examined the lubricants that were recommended by the equipment manufacturer and supporting documentation.

d) Determined the lubricants that were currently in use, which included quantity, cost and source of supply.

e) Listed the schedules for each lubrication point, including frequency and quantity to be applied.

Stage 2: Established Lubrication Schedules and Selection

a) Reviewed current lubrication schedules, including type and amount of lubricant used, frequency of application, and application methods.

b) Determined if it is the best lubricant for the specific application.

c) Analyzed each piece of rotating equipment and determined the adequacy of lubrication schedule status.

d) Investigated opportunities to replace inadequate manual and malfunctioning automatic systems.

e) Analyzed operating records, such as frequency of scheduled and unscheduled downtime, to prepare a viable lubrication schedule.

f) Recorded and reported the amount and type of lubricant consumed by rotating equipment.

g) Placed tags at equipment grease point that needed lubrication schedule e, and application method.

Stage 3: Lubrication Program Charts

Lubrication checklists were prepared using the information obtained in stage 2; this consisted of the following:

v  Equipment number

v  Name of equipment

v  Parts to be lubricated

v  Quantity for initial fill

v  Type of lubrication system

v  Recommended lubricants and alternatives

v  Remarks for lubricants change

This was carried out for all the rotating equipment in the plants and we were able to develop their lubrication database. A sample of lubrication database for Ammonia Plant is shown in Table 1.

Lubricants Interchangeable Charts

Lubricants Interchangeable Charts provided a guide to the Preventive Maintenance Engineer in making recommendation to Operation and Maintenance Departments to lubricants alternatives in the absence of the recommended, as shown in Table 2.

                         LUBRICANTS INTERCHANGEABLE CHARTS

PRODUCTS	MOBIL	SHELL	CHEVRON	CASTROL	TEXACO	UNION
SPINDLE OIL	Velocite 6	Tellus (Spindle) 10	AW Machine Oil 10	Hyspin R&O 10	Spindura 10	Turbine 10
	Velocite 10	Tellus (Spindle) 22	AW Machine oil 20	Hyspin R&O 22	Spindura 22	Turbine 22
R & O TURBINE OIL	DTE Light	Turbo T 32	GST 32	Hyspin R&O 32	Regal R&0 32	Turbine 32
	DTE Medium	Turbo T 46	GST 46	Hyspin R&0 46	Regal R&O 46	Turbine 46
	DTE Heavy Medium	Turbo T 68	GST 68	Hyspin R&O 68	Regal R&O 68	Turbine 68
	DTE Heavy	Morina 100	GST 100	Hyspin R&O 100	Regal  R&O 100	Turbine 100
	DTE Extra Heavy	Morlina 150	GST 150	Hyspin R&O 150	Regal R&O 150	Turbine 150
	DTE BB	Morlina 220	GST 220	Hyspin R&O 220	Regal R&O 220	Turbine 220
ANTI-WEAR HYDRAULIC OIL	N/A	N/A	N/A	Hyspin AW 22	N/A	N/A
	DTE 24	Tellus 32	AW Hydraulic 32	Hyspin AW 32	Rando HD 32	UNAX AW 32
	DTE 25	Tellus 46	AW Hydraulic 46	Hyspin AW 46	Rando HD 46	UNAX AW 46
	DTE 26	Tellus 68	AW Hydraulic 68	Hyspin AW 68	Rando HD 68	UNAX AW 68
	N/A	Tellus 100	N/A	Hyspin AW 100	N/A	UNAX AW 100
WAY LUBRICANTS	Vactra-1	Tonna V 32	N/A	Magna BD 32	Hydra-Way 32	Way Oil HD 32
	Vactra-2	Tonna V 68	Vistac 68X	Magna  BD 68	Hydra-Way 68	Way Oil HD 68
	Vactra-4	Tonna V 220	Vistac 220X	Magna BD 220	Hydra-Way 220	Way Oil HD 220
GEAR OIL (INDUSTRIAL USE)	Mobilgear 626	Omala 68	NL Gear 68	Alpha EP Gear 68	Meropa 68	Extra-Duty NL 2-EP
	Mobilgear 630	Omala 220	NL Gear 220	Alpha EP Gear 220	Meropa 220	Extra-Duty NL 5-EP
	Mobilgear 634	Omala 460	NL Gear 460	Alpha EP Gear 460	Meropa 460	Extra-Duty NL 7-EP
WORM GEAR (AUTOMOTIVE USE)	600W Cylinder Oil	Valvata J460	Cylinder Oil W460	Alpha Worm Gear 460	N/A	N/A
	Mobilube HD	Spirax HD	Delo Gear Oil	N/A	Multigear EP	MP Gear Lube LS
GREASE	Mobilux EP 2	Alvania EP 2	Dura Lith EP 2	EP 2	Multifak EP 2	Unoba EP 2
TRANSFORMER INSULATING OIL	MOBIL ECT 35	DIALA B		CASTROL ES 148 INSULATING OIL
HYDRAULIC CLUTCH AND BRAKE FLUID	HYDRAULIC BRAKE FLUID	DONAX B		CASTROL BRAKE FLUID	SUPER HD BRAKE FLUID
AUTOMATIC TRANSMISSION FLUID	ATF 220	ATF DEXTRON 11		CASTROL TQ-DEXRON 11	TEXMATIC FLUID 9226
AIR COMPRESSOR OIL (RC GRADE)	RARUS	CORENA H		AIRCOL PD	REGAL R & O
	68	68		68	68
	100	100		100	100
	150	150		150	150

                                                                        Table 2: Lubricants Interchangeable Chart

Viscosity is the property most widely accepted for identifying lubricants within a category. The chart in Table 3: shows acceptable limits of lubricants based on their ISO viscosity grade numbers.

ISO Viscosity Grade Number	Mid-Point Viscosity, cSt @ 40ºC	Kinematic Viscosity Limits, cSt @ 40º
		Minimum	Maximum
ISO VG 2	2.2	1.98	2.42
1SO VG 3	3.2	2.88	3.52
1SO VG 5	4.6	4.14	5.06
ISO VG 7	6.8	6.12	7.48
ISO VG 10	10	9.00	11.0
ISO VG 15	15	13.5	16.5
ISO VG 22	22	19.8	24.2
1SO VG 32	32	28.8	35.2
ISO VG 46	46	41.4	50.6
ISO VG 68	68	61.2	74.8
ISO VG 100	100	90.0	110
ISO VG 150	150	135	165
ISO VG 220	220	198	242
ISO VG 320	320	288	352
ISO VG 460	460	414	506
ISO VG 680	680	612	748
ISO VG 1000	1000	900	1100
ISO VG 1500	1500	1350	1650

                                      Table 3: Lubricants Acceptable Limits based on ISO Viscosity Grade

Note: ±10% of ISO VG gives the minimum and maximum, while the average of minimum and maximum gives the mid-point. The oil analysis from the laboratory on any lubricant based on the ISO VG was acceptable; if the result was between the minimum and maximum limits.

     

Stage 4: Computerization of Lubrication Program

The various lubrication programs for the rotating equipment were yearly scheduled. These were compiled and installed using LOTUS 123 software into the PM/ECM Computer Maintenance Management System. On weekly basis rotating equipment scheduled for lubrication were printed and sent to maintenance personnel in the Plants for execution, as shown in form B. The maintenance personnel liaise with operation personnel to make ready the equipment for their Relubrication checks to be carried. Upon completion and duly signed were sent back to the PM Engineer, who ensured that they were fully implemented by routine inspections of rotating equipment in the Plants.

  

Plants: Urea Granulation                                                                 Date:………………………. 2813 LA-LD: Palletizer Infeed Conveyor
Lubrication Tasks	Lubricants	Remarks
Motor Bearing Brake End	ESSO UNIREX N3
Motor Bearing Drive End	MOBILUX EP2
Gear Box	MOBILGEAR 630
Roller Chain	GRAPHITE
Flange Bearing	MOBILUX 2
Guides	MOBILUX 2
Urea Operations Suptd:…………………………                Date:………………………………. Area Maintenance Suptd:……………………….                Date:……………………………….

             Form-B: Lubrication Checklist/Tasks for 2813 LA-LD, Palletizer Infeed Conveyor

 Lubrication Monitoring and Evaluation Program

To ensure that the scheduled Lubrication program sent to the Plants were effectively implemented, we carried out routine visual inspections of rotating equipment facilities and had regular meetings with Plants Operations Personnel. At the end of the meeting, departments that were unable to execute their Lubrication programs due to Plants operations were rescheduled. Every quarter from the executed Lubrication checklists/program received from the various Plants Maintenance Departments, their level of compliance were presented in the form of bar-chart.

LUBRICANTS MONITORING PROGRAM

Lubricants used in NAFCON Plants were closely monitored to ascertain their conditions as they detected early signs of equipment failures. Samples of lubricants were routinely taken and analyzed by the laboratory. The properties that were monitored depended on the application and environment. They included the following:

1.      Appearance or colour

2.      Water content          

3.      Neutralization number

4.      Viscosity

5.      Flash point

6.      Oxidation stability

7.      Particle count

8.      Rust Test (D665A)

9.      Sediment

We were mostly interested in appearance, water content and oxidation stability. 

The PM Unit in NAFCON monitored the status of lubricants in some critical rotating equipment monthly, by taking samples of the lubricant. This we do by liaising with Operation Personnel and the samples were taken before the filters of the lube line; which ensures the actual status of the lubricants and sent to the laboratory. This provided us with useful information about lubricant condition, machine condition and contamination levels in bearings, compressors, gearboxes and engines. By sampling and analyzing these oils, we were able to detect degradation in lubricant properties, excessive wear in lubricated components, a built-up of contaminants and moisture, improper use of the wrong lubricant and other conditions that affected reliable equipment operation.

The result of the lube analysis were sent to the Preventive Maintenance Engineer to ascertain their acceptable limits; based on this, Maintenance and Operations Departments were advised on actions to be taken. It was also my responsibility as a PM Engineer to ascertain the viscosities of newly procured lubricants, to ensure that they met manufacturer’s specifications before certification for usage in the Plants.  

 ROUTINE PLANTS INSPECTIONS

The PM Engineer carried out daily inspections of rotating equipment, made use of human senses, such as visual inspections, hearing, torch and smell. In each piece of equipment, checked for the following:

-          Leaks such as process fluids, lubricants, water, steam, etc

-          Unusual noises

-          Excessive vibrations

-          Hot bearings

-          Excessive cavitations (checked suction / discharge pressure)

-          Corrosion

-          Foundation problems

-          Poor insulation

-          Lubricants condition for water or contaminants and proper levels

-          Condition of guards

-          Cleanliness of motor cooling fans

These inspections were carried out using Form-C, which was completed while inspections; and the outcome of the findings were communicated to Maintenance and Operation with advice on actions to be carried out.

CONSTRAINTS AND SOLUTIONS IN IMPLEMENTING PM AND LUBRICATION PROGRAMS IN NAFCON

1. Plants Operations

The Plants operations constituted major constraints towards effective implementation of PM and Lubrication programs, as most times the Operation Departments could not release the equipment to Maintenance Personnel to execute their PM and Lubrication Check Tasks on them; while in production. This made us to regularly re-schedule the PM and Lubrication programs on these equipment to when they will be made available to maintenance personnel.

2. Equipment Manual

The unavailability of some equipment manual delayed the design of PM and Lubrication programs for these equipment. In these cases, we had to rely on historical maintenance record of the equipment.

3. Spare Parts and Materials

These were also constraints in the implementation of scheduled PM and Lubrication programs, as some of PM checks needed consumables like lubricants, electrodes, safety consumables, spare parts, etc which sometimes were unavailable. The management of NAFCON was advised by PM Unit to stock them in the warehouse.

4. Laboratory Equipment and Reagents

The laboratory was not to perform some important lubricant analysis, such as ferrographic and spectroscopic analysis due to absence of equipment and reagents. The management of NAFCON was advised to purchase them or perform the analyses with laboratories outside; as these will enable the PM Unit to also know the operating conditions of the rotating equipments as well as the lubricants.  

5. Absence of Important PM toolkits

The PM Unit lacked some important PM toolkits needed to perform checks on the rotating equipment, these included the following:

a.     Ultrasonic toolkit: Needed to monitor bearing conditions and to ensure proper lubrication.

b.    Infrared thermograph toolkits: Useful for detecting overheated bearings; misalignment in belts, sheaves and couplings; faulty steam traps; and other anomalies that exhibit a thermal change as components degrade

The PM Engineer advised the Equipment Condition Monitoring (ECM) Unit to routinely carry out vibration analysis checks on the rotating equipment, which provided maintenance department with useful information on early detection of problems and their solutions.