second progress report 213693

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King Fahd University of Petroleum

and Minerals

Second Progress Report

Prepared ForDr. Anwar Sheikh

Done By

Musaab Faleh Al-Subaii

ID: 213693


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20-11-2006CONTENTS

INTRODUCTION

I. Plan to Be Fallowed 3

II. Valve Shop ...3

A.Valves Categories

B. Valve Parts

C. Types of valves

D.Valve Maintenance

III. Fabrication and Wilding Shop ..10

IV. Reliability Unit11

V. T and I Planning..13

CONCLUSION

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LIST OF FIGURES

Fig 1: Check valve..4

Fig 2: Relief valve...4

Fig 3: Valve basic parts...5

Fig 4: Big gait valve example.6

Fig 5: Gait valve..6

Fig 6: Glob valve.7

Fig 7: Needle valve.7

Fig 8: Plug valve.8

Fig 9: Ball valve..8Fig 10: Butterfly valve....9

Fig 11: Valve packing system..10

Fig 12: CCR blower.....11

Fig 13: Bearing failure caused by lack of lubricant in the second repair.12

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Introduction:

This is my second progress report in my COOP program at Saudi Aramco

from June 24 to December 27. In my second progress report, I will discus the

places that I was assigned to. I went to the valve shop, fabrication and welding

shop, reliability unit and the T&I planning.

I. Plan to be followed:

Week Date Department

14--15 23/9/2006-4/10/2006 Valve shop16--17 7/10/2006-18/10/2006 Fabrication and wilding shop

1819 21/10/2006-1/11/2006 Reliability unit

20 4/11/2006-8/11/2006 T and I Planning

2122 11/11/2006-22/11/2006 Process Area 1,2 and 3

II. Valve shop:

In this shop I learned basic types of valves and how they perform and the

maintenance procedure. The basic function of all valves is to control flow in pipesystem.

1. Valves Categories:

Valves can be classified in to four categories based on how they work:

1. On /off valves: This type of vales is the most common used valve. They

stop or open the flow of liquids or gases in piping lines. They can be usedjust in emergence cases to be partially open (called the throttling position).

However, if they are use to much in this position, they will be damaged

caused by the vibration.

2. Throttling valves: These valves are used to regulate or throttle flow.

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3. Check valves: They allow fluid flow in one direction.

Fig. 1: Check valve.

4. Relief valve: it is used to relief excess presser from a process system toprotect equipment and personal.

Fig. 2: Relief valve.

2. Valve Parts:All valves have the same basic parts which are:

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1. Body

2. Disc

3. Stem4. Stem gasket

5. Gasket

6. Guide7. Studs and nuts

8. Lower spring washer

9. Bonnet10. Spring

11. Upper spring washer

12. Washer13. Lock nut

14. Adjusting screw15. Cap


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1. Valve body: it contains author valve parts and to provide connection with

pipes. There are three methods of attaching valve with piping system: by

wilding, threading and with flange. Welded connections are used in steam

line or high presser process piping where other connections may fail or

leak. Threaded connections are used in small valves with low presser

system. Flanged connection are used commonly were operating conditionmay require frequent valve replacement or repair.

2. Seat and Disc: the seal is used with the disc to control flow throw the

valve. If the disc moves to words the seat, the flow throw the valve is

reduced and when the disc is pressed against the seat, the flow will stop.

3. Bonnet: it seals the top of the valve body.

4. Stem: it is attached to the disc.

5. Hand wheel: it is attached to the stem.

6. Stuffing box: contains the packing material which prevents the leakagebetween the stem and the bonnet.

7. Packing gland: which has two nuts so it can be fasten when leakage

accurse.

Fig. 3: Valve basic parts.

3. Types of valves:

1) Gait valve: Used for isolating equipment such some pumps have valves in

the intake and discharge lines and can be isolated so the pump can be

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Packin land

Stem

Disc

Hand wheel


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removed for maintenance. Some gait valves have long valve stem and

bonnet. This type of vale is an on/off valve.

Fig. 4: Big gait valve example.

Fig. 5: gait valve.

2) Globe valve: this type has a glob shape body, seat bonnet, discharge, stem

with a hand wheel attached to it, stuffing box, packing, packing gland and

gland nuts.

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It can be an on/off valve and throttle valve.

Fig. 6: glob valve.

Globe valve are designed in this shape to prevent uneven wear of seat and disc.

3) Needle valve: its the same as the globe valve, it disc is shaped like a

needle. This type can control very small flow with accuracy.

Fig.7: Needle valve.

4) Plug valve: It is designed for on-off situation were a quick valve operation isrequired and a tight shut off. It has a plug instead of disc. This type can open or

close by applying just a 90 degree on the handle. Operation can know if the valve

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is open or close by seeing the handle position. If the handle is aligned to the

piping system, the valve is in open and if it is with a 90 degree, it is close.

Fig. 8: Plug valve.

5) Ball valve: this type is the same as the plug valve but it has a ball instead of plug.

Fig. 9: Ball valve.

6) Butterfly valve: They have a thin body and relatively they need less space inpiping system.

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Fig. 10: Butterfly valve.

4. Valve Maintenance:In the valve shop, valve came either for a routine inspection and

maintenance or for a problem has been reported. Every valve in the refinery has a

serial number with the last maintenance due date. In Aramco, the period for a

maintenance routine is 3to5 years. Common valves problem are as fallowed:

o Packing leak: this is the most common problem valve can have. The

packing is typically a rope light material made from a strong natural or

synthetic fiber. It controls leakage around the valve stem. Valves contain a

packing gland, packing, gland follower and packing gland nuts. A smallleakage can be stopped by tightening the packing gland nuts. However,

some time this can not help because the packing is damaged and needs to

be replaced. The packing can be removed in some valve with out removingany valve part just loosing the packing gland nuts and removing the

packing by a packing hook. There are twisted packing(flexible and well

suited for low presser application),square braid packing(stronger and

flexible), braid over braid packing(designed for high presser application)

and interlocking braid packing(high presser application and hard to

compress).

o Body to bonnet leak and connection leak: this problem is cased by gasket

worn out or some valve parts have some scratch. This leak can be fixed by

putting a new gasket or applying some lapping on the part so the surface

can get flat.

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o Internal leak: this happen when the disc and seat are worn out. It can be

fixed by applying lapping to flat the surfaces of the seat and the disc. But

some time changing the parts are must. This leakage can be detected by

plant instrumentation.

Fig.11: Valve packing system.

After the maintenance is done, the valve is tested for any leakage in a hydro test

machine. This test is mostly performed to relief valve to check if it opens on thespecified presser and it does not leak as the presser build up.

III. Fabrication and Wilding Shop:This shop was the most boring time I ever had in my coop program. There

were a little work and I gained little knowledge. The most work was on piping

welding and threading with performing a hydro test. Piping materials are as

fallowed:

Mild carbon steel

Galvanized steel

Aluminum

Stainless steel Glass and fiberglass (I did not see it)

Plastic

Copper and cast iron

In the beginning, a piping system is inspected for any defect or damages caused by

Hammering. Cracks in piping can be fixes by removing some of the material from

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Stuffin box

Packing gland


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the crack position, filled with the same material, polished and then it is subjected

to heat treatment to have uniform properties. There are three type of pipe fitting:

thread fitting, welded fitting and flanged fitting. Threaded fitting are used in small

pipes with low presser and temperature. Welded piping is for high temperature and

presser like steam lines. For flanged piping, it is used for big pipes and easy

replacement. For welding there are tree types of welding in the shop: SMAW(stick mashing arc welding), GTAW (gas tungsten arc wilding) and gas welding.For carbon steel wilding, we use 7018 welding rod. For stainless steel, we use the

same stainless steel number like 304, 309, 308 and 316. Cast iron wilding can be

welded by either a eutectic rod or cast iron rod. For cutting, carbon steel can be cut

by oxygen acetylene. Stainless steel, aluminum, brass will be by plasma and can

be used cast iron.

IV. Reliability Unit:In the reliability unit, I spend just one week due to the vacation. I have

observed a problem with the CCR blower. This blower failed two times in a short

period. I will discus the problem.It was observed that the blower motor trip in high

load when going from 1800 to 3600 rpm and the inboard bearing was having a

high temperate about 100 C at the start up at 3600 rpm. As I mentioned above, the

motor was sent to the mechanical shop (MSSD) twice. The first time was due to

seizure from lack of bearing grease and second time was due to vibration fromexcessive bearing housing clearances. The bearings are single row, very heavy

duty Angular Contact ball bearings, more than capable of handling the motor

power and loading. For the outboard bearing had 56 C. It was checked that the

rotation is free from frication and smooth by hand rotating which meaning that no

coupling misalignment or motor internal misalignment is acting on the bearing.

The temperature problem is due to thermal growth loads on inboard bearing

caused by motor rotor growing axially due to normal lamination heating and lack

of rotor axial growth clearance in motor bearing housings. If the inboard motor

bearing outer race is not allowed to move axially, then thermal stress will apply

forces in the range of thousands of pounds, against the bearing, causing high

temperatures and early failures. It was confirmed that the inboard bearing housing

and found it fully locked axially with zero axial growth clearance. The thermal

deferential growth can be calculated which is

TDG = delta T * length * coefficient of expansion of steel/cast iron.

= [(90 C 55 C) = 45 C = 63 deg F] * 65 inch * 0.0000067 inch. Deg F

= 0.027 inch

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So, a 0.03 inch is necessary at the inboard housing to allow freedom of axial rotor

growth and this is done by installing a gasket.

For the motor trip, it was tested after the modification and still having the

problem. Electricians confirmed that motor terminal voltage drop at 3600 rpm full

load startup is within motor limits. Because this problem is only in the motor

blower start up, it has been solved by lowering system gas pressure, to reduce gasdensity, which reduces the blower aerodynamic loads, allowing low torque at 3600rpm startup.

V. T and I Planning:The main job of T&I is to provide maximum plant /unit reliability from a

well planned, cost effective, safe T&I without compromising equipment integrity.Some jobs of this unit are planed for total refinery shot down for inspection and

repair (like the process area) and some just need to be isolated (like tanks). They

are responsible for just stationary equipment (for example heat exchanger,

condensers, tanks, boilers, etc. I was concerned about tanks maintenance schedule.

Tanks are inspected every 10 years and Aramco planning for 15 years for less

cost. Tanks consist of sell plats, roof, bottom plats, sketch plat and drop plat toprevent rain water going under the tank. Tanks defer by there roofs. There floating

roof, cone roof, fixed and spherical roof.

When the unit determines to work on a tank, operators isolate the tank and

drain the product in it. The man hole is then opened and tank is finned to take outthe fumes. After the operator checks if the fumes are in the acceptable range for

men to work, tank is then cleaned from the remaining product. Grit blast is done

on the tank to remove old paint and corrosion. After that, the tank is inspected by

MFL to see if the thickness is in the right range. If not, then the damaged plat will

be replaced. Panting is after that with some coating. The tank then is hydro tested

by injecting sea water with some presser to see if there is any leakage.

Conclusion:Still month remaining, and am going to TSU for two weeks and its the realengineering as what I heard. Inspection and corrosion unit is the next for a week. I

have seen some problem that not been solved yet by the reliability unit and I

wished that I had time see the solution like some pump have continuousmechanical flair out from the usual.

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second progress report 213693

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