Coal Mill Part(1)

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Coal Handling & Safety Sinai Grey

Wael A.M. El-Noby

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Layout of The Course Subjects o o o o o o o o o

Introduction Maintenance Philosophy and Why is it done Atox Vertical mill Design and function Fire fighting ATEX Directive Bag house filter and coal filter Pfister and coal feeder Safety precauions for Maintenance & inspection Exercise and Discussion

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What is Maintenance •

Maintenance involves keeping the workplace, its structures, equipment, machines, furniture and facilities in good repair and operating efficiently and safely. It includes many tasks including repairing, replacing, servicing, inspecting and testing. The term could also be used in relation to the importance of keeping your staff safe, fit and healthy.

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Maintenance Types

There are two main types of maintenance work. Routine/preventative maintenance is usually planned and includes scheduled inspections repairs and replacement to make sure everything continues to work. It can be compared to an annual service on your car. Corrective maintenance is needed when things go wrong or break downs occur demanding reactive action to be taken to get things up and running again. It can be compared to having a repair carried out on your car after a part has failed.

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Maintenance and Why Is It Done •

Regular maintenance is essential to keep premises, equipment, machines and the work environment safe and reliable. It helps to eliminate workplace hazards. Lack of maintenance or inadequate

maintenance can lead to dangerous situations, accidents and health problems. •

It is important that a planned maintenance programme is in place

and that all maintenance work is risk assessed before beginning the task

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Maintenance and Risk •

Who is affected/ most at risk?

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Everyone is affected. Those who carry out maintenance work are at risk if the tasks have not been assessed and adequate controls are in place to keep them safe but others would be affected if maintenance work was not carried out as they could be working with or around dangerous equipment or within a dangerous environment.

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Maintenance and Risk Contractors brought in to carry out maintenance work can be particularly at risk as they may be unfamiliar with the workplace and the procedures in place for working safely. Maintenance can be dangerous, it is estimated that, between 25 and 30% of all manufacturing industry deaths in Britain result from maintenance activity. This doesn’t include the long-term health problems associated with maintenance. One example of this is the recent HSE campaigns highlighting the numbers of workers exposed to asbestos during maintenance work in buildings where asbestos is present.

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Maintenance and Risk •

What are the main risks?

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Maintenance work can in itself be hazardous. It can also make the workplace more hazardous while the work is being carried out. A risk assessment will be needed to identify suitable control measures to manage the maintenance work effectively.Some of the main problems associated with maintenance work are:

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working at height (risk of falls or falling tools and equipment)

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gaining access to the equipment (confined spaces or harsh environments)

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Proactive Maintenance •

electrical hazards (shocks, burns if not isolated)

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equipment (injuries from moving parts if not isolated)

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musculoskeletal disorders (exerting force, poor access or working in a cramped space)

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exposure to asbestos fibres (not always identified and marked?)

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exposure to harmful chemicals (used in the machine being maintained?)

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exposure to dust (again, through the machine being maintained?)

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exposure to legionella (in water systems and air conditioners)

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exposure to noise (working on or using noisy equipment)

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Proactive Maintenance •

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It is also known as “Prevention Maintenance”. This philosophy based on tracing all failures to their root cause. Each failure is analyzed and proactive measures are taken to ensure that they are not repeated. It utilizes all of the predictive/preventive maintenance techniques discussed above in conjunction with root cause failure analysis (RCFA). RCFA detects and determines the problems that cause defects. It ensures that appropriate installation and repair techniques are adopted and implemented. It may also highlight the need for redesign or modification of equipment to avoid recurrence of such problems.

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2

Check List

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Always use a checklist when performing an inspection.

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The checklist may be of your own design, one provided by the manufacturer of the equipment being inspected, or one obtained from some other source.

3 •

Routine and Required Inspections

Performing these inspection according to recommendation

and documents.

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4

Maintenance Manual

The manufacturer’s equipment maintenance manual contains complete instructions for maintenance of all systems and components installed in the equipment

5

Overhaul Manual

The manufacturer’s overhaul manual contains brief descriptive information and detailed step by step instructions covering work

normally performed on an equipment.

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Accurate Measurements and Condition Monitoring Performing these accurate measurements by using different tools

and compare it with documents.

Historical Record The previous items has been recorded to form a complete picture for each equipment status and to make our investigation easier in case of problems detection and it facilitates problems analyzing and find the specified root cause analysis for equipment.

Interpretation and Analyzing of Results The success and reliability of inspection depends upon the inclusion with which the data has been collected.

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Oil Analysis and Wear Oil Analysis Tests A good oil analysis package looks at four main Points to provide A unique way of indicating what is going on inside the equipment: 1. Oil condition: development specifications (oxidation, viscosity, additives, etc.) 2. Equipment condition: type of wear (normal, abnormal) 3. Contaminants: type and quantity (dirt, water, debris, other lubricants, etc.) 4. Equipment operating conditions: (load, temperature, alignment, balance, speed,

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Oil Analysis and Wear Oil Analysis Tests There are a few key tests for industrial lubricants that show their general condition.

These tests includes the following categories: I.

Viscosity

II.

Water content

III. Acid number (AN) IV. Oxidation V. Elemental analysis

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1 1

Viscosity

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It is a measure of a fluid’s resistance to flow.

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It is the single most important property of a lubricant.

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The most common units for describing kinematic viscosities are centistokes (cSt), which are reported at 40°C (104°F) for industrial

gear lubricants. •

Where a lubricant’s viscosity is defined in ISO-VG grades, a change of approximately ±24% from typical levels indicates a need for

corrective action.

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•

If the lubricant’s viscosity shows an Increase above the typical value, it may be due to high soot or insoluble content, contamination with higher viscosity lubricant and oxidation.

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Corrective action should be applied such vacuum dehydration, and filtration to remove particulate and/ from the oil, thus extending oil life.

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Also the correction action may be adding new oil to refresh the charge or change the whole charge.

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If the lubricant’s viscosity shows a Decrease, it may be due to water contamination, dilution with lighter viscosity oil, or shear down of a viscosity index improver.

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Corrective action should be taken is change the oil, either partially or completely.

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2 1 •

Water Content

A lubrication oil is considered absolutely fit for further use only if its

water content is less than 0.2 %. •

Water can enter the oil from a cooling system leak, or bad sealing. The nature of water (fresh or salt) can be determined from the

sodium and magnesium levels detected. •

Water reduces film strengths and reacts with aggressive components in the oil to form acids. These acids degrade the oil and attack the equipment component.

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Corrective action should be taken is first dehydrate the oil and second is change the oil, either partially or completely.

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3 1 •

Acid Number ( AN)

The acid number (AN) is the amount of acidic substances present in the lubricating oil.

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A high value implies that the oil is degraded by high acidity.

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If the oil has a high acid number and remains in service, the equipment elements will be attacked and create corrosion.

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Corrective action should be taken is change the oil, either partially or completely.

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4 1 • •

Oxidation

Oxidation is measured using infra-red (IR) test methods. This test is run for all samples, with the exception of some synthetic based oils.

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An oxidized oil normally increases its viscosity and turns dark in color.

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The oxidation process can be due to high operating temperatures.

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Corrective action should be taken is change the oil, either partially or completely.

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5 1 •

Element Analysis

Elemental analysis measures the presence of elements in the oil, in

parts per million (PPM). •

This test is run for the purpose of diagnosing wear.

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Limit values for each element depend on the equipment builder and

the application. •

If the values are above the attention limits, the test indicates changes in machinery wear and lubricant contamination.

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Corrective action should be taken is fixing any problem, according to the element(s) shown in the test and change the oil, either partially or completely.

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If the values are above the alert limits, the test indicates severe changes in the machinery regime wear.

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Corrective action should be taken is stop the equipment and inspect it for failures or damages, then fix the problem and change the oil completely.

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Technical Reports Writing the technical reports which indicates equipment technical data, the problem and discussion upon documents, measurement and actual notes from site. Lubrication Circuit

Planning for Shutdown Planning for shutdown according to the jobs required because of all inspection work and scheduling these jobs with full co-

operation between all departments.