FABRICATION OF OIL SKIMMER MACHINE.docx

8/19/2019 FABRICATION OF OIL SKIMMER MACHINE.docx

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ABSTRACT

Oil Skimming Although designs vary, all oil skimmers rely on specific gravity, surface

tension and a moving medium to remove floating oil from a fluid’s surface. Floating oil and

grease cling to skimming media more readily than water, and water has little affinity for the

media. This allows skimming media in the shape of a belt, disk, drum, etc. to pass through a

fluid surface to pick up floating oil and grease with very little water. This oily material is

subseuently removed from the media with wiper blades or pinch rollers. Oil skimmers are

simple, dependable and effective tools for removing oil, grease and other hydrocarbons from

water and coolants. Often, an oil skimmer by itself can achieve the desired level of water

purity. !n more demanding situations, oil skimming is a cost"effective means of removing

most of the oil before using more complicated and costly treatments such as coalescers,membrane filters and chemical processes. #rease skimming involves higher viscosity

hydrocarbons. Oil skimmers must be euipped with heaters powerful enough to keep grease

fluid for discharge. !f the floating grease has formed into solid clumps or mats, a spray bar,

aerator or mechanical apparatus can be used to break up grease mats and facilitate removal.

This topic describes the development of the OS with typical working model.


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TABLE OF CONTENTS

CHAPTER NO. TITLE PAGE NO.

ABSTRACT

LIST OF TABLE

LIST OF FIGURES

LIST OF SYMBOLS

1. INTRODUCTION

1.1. OIL

1.2. OIL SKIMMER

1.3. SKIMMER TECHNOLOGIES

2. TYPES OF SKIMMERS

2.1. DISC

2.2. ROPE MOP

2.3. DRUM

2.4. BRUSH BELT

2.5. NON OLEOPHILIC

2.5.1. SUCTION

2.5.2. WEIR

3. OIL SKIMMER WORKING PRINCIPLE

4. DESIGN CALCULATIONS

4.1. OIL RISING VELOCITY4.2. CORRESPONDED-FEASIBLE SEPARATOR SIZE

4.3. TORUE ! TENSION IN BELT

4.4. DC MOTOR

4.5. STEEL SELECTION AND PROPERTIES

4.". BELT SELECTION

5. LIST OF COMPONENTS

". PROTOTYPING

#. CONCLUSIONS AND PROPOSAL

REFERENCES

LIST OF TABLES


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LIST OF FIGURES


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LIST OF SYMBOLS$ ABBREVIATIONS AND NOMENCLATURE


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INTRODUCTION

Oils

Oil can be defined as$ %A viscous liuid derived from petroleum, especially for use as a fuel

or lubricant& or %Any of various viscous liuids which are insoluble in water but soluble in

organic solvents and are obtained from animals or plants& 'O(ford )ictionaries, *+*-. Oils

are, based on these definitions, divided into two categories with different chemical

composition mineral oils 'also called crude oils- and organic oils 'also called fats- in which

essential oils are included.

Oil Skimming

Overview Oil skimming is a low"tech but reliable and efficient techniue. An oil skimmer is

defined as$ %Any mechanical device specifically designed for the removal of oil 'or oil"water

mi(ture- from the surface of water without altering the water’s physical and/or chemical

characteristics&. '0OAA, *++- The skimming principle, upon which the techniue relies, is

dependent on three physical properties of oils, namely specific gravity, surface tension andaffinity. 1ost oils have a lower specific gravity than water, which allows it to separate from

water and float to the surface unless agitated. These oils are possible to collect using an oil

skimmer. Other oils do the opposite and, if not agitated, sink to the bottom of the water and

must be collected by other means than skimming. 'Abanaki, *+- The light oils, which can

be skimmed off the water surface, are possible to collect due to the surface tension and

affinity of the oil. 1ost oils have little or no affinity for water, which prevents mi(ing of oil

and water. As the skimming medium enters the water, the oil wets the surface preventing

water from doing the same. Any water on the surface is pushed away as more oil attaches to

the surface because of the surface tension of the oil.

2owever, it is important that the skimming medium is not submerged too deep into the water,

as it may cause the oil to be washed off the skimming medium and thereby lowering the

efficiency. '3ersson 4. , *+5- A number of factors are to be taken into account when

selecting skimmers but the most important aspects to consider are the viscosity and the

adhesive properties of the oil intended to be skimmed. !n open sea spills, other importantfactors are sea state, currents, and level of debris. !n relatively predictable situations such as


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at fi(ed facilities, for instance industry processes, marine terminals and refineries, the type of

oil handled may be known and hence the type of skimmer to be used can be selected

accordingly.

Subseuently, a versatile skimmer able to handle different kinds of oil and various situations

may be preferable in some cases, but is to be kept in mind that no single skimmer can cope

with all potential situations that may arise. A combination of skimmers is hence desirable,

particularly as the oil weathers. '!TO3F, *+*- The second most important factor to assess is

the skimmer’s intended use and e(pected operational conditions. )epending on if the

skimmer is to form an integral part of a vesselmounted, offshore recovery system or if it is to

be deployed manually in a port or fi(ed in a cooling water reservoir the selected type of

skimmer will differ and aspects such as si6e, robustness and ease of operation, handling, andmaintenance can then be evaluated. '!TO3F, *+*-


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S%&''&() T*+,()&*/

The mechanisms through which oil is removed from the water surface can be divided into

oleophilic techniues, which rely on the adhesion of oil to a moving surface, and non"

oleophilic techniues. 0on"oleophilic techniues include weir skimmers relying on gravity,

suction systems, and mechanical skimmers, which physically lift the oil with scoops, or

grabs. '!TO3F, *+*-

Oleophilic Skimmers Oleophilic skimmers recover oil based on the properties of specific

materials, which have greater affinity for oil than for water. There e(ist numerous types of

oleophilic skimmers and they are therefore divided into subgroups such as disc skimmers,

drum skimmers, rope mop skimmers, belt skimmers, and brush skimmers. 7egardless of the

type of skimmer, the principle behind the techniue used is the same for all oleophilic

skimmers. The skimming head, i.e. the part with the oleophilic surface, is rotated or pulled

through the oil slick and the oil is then scraped or suee6ed off and the oil removed into a

sump to be pumped or sucked away. '0OAA, *++- '!TO3F, *+*- Oleophilic skimmers

usually achieve the highest ratio of recovered oil in relation to entrained water, also referred

to as the recovery efficiency, compared to other skimmer types. Oleophilic skimmers reach

their highest efficiency when handling medium viscosity oils 'between ++ 8 *+++ cSt-.

)iesel, kerosene and other low viscosity oil products generally do not adhere to the oleophilic

surface in sufficiently thick layers to attain high recovery rates. 2igher viscosity oils such as

heavy bunker oil on the other hand, can prove to be difficult to remove due to its tendency to

form large clumps in the water, which are too heavy and compact to be skimmed.

9omparatively, oil"water emulsions can be almost impossible to recover with oleophilic

skimmers, due to the fact that emulsions are nearly non"adhesive. '!TO3F, *+*- Oleophilic

materials are often made of some form of polymer even though metal surfaces have shown to

be effective. Furthermore, studies show that discs and drums with grooved surfaces result in

higher recovery rates than smooth surfaces. '!TO3F, *+*- ':ro;e < 4eller, *++=-


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TYPES OF SKIMMERS

)isc Skimmers

)isc skimmers work best with lighter types of oil 'medium viscosity- and cannot handle

emulsified oil. 2owever, disc skimmers can be used for open sea operations and are

controlled by crane operators. The volume and weight of the disc skimmers are uite large

due to the si6e and number of rotating discs '0OAA, *++-.

7ope 1op Skimmers

7ope mop skimmers use ropes floating on the surface of the water to retrieve the oil. 7ope

mop skimmers are large units and reuire the use of a crane during the entire operation for

launching from either a vessel or shore. The oil is recovered by the ropes, which are then

wrung releasing the oil into a collection tank either on board the vessel or on the shore. This

skimmer type is not sensitive to waves but is normally only used for single sweep operations.

>ertical rope mop skimmers are most suited for lighter oil types as very little water is

collected during recovery. )ebris or ice will not affect the skimming operation '0OAA,

*++-. 7ope mop skimmers are ideal for shallow water conditions, as the rope reuires

minimal water to float. Furthermore, 7ope mops are ideal in trash"laden environments since

the trash falls off the ropes as they come up to the wringer unit. '9leanup Oil, *++5-

)rum Skimmers

)rum skimmers are driven by air or hydraulics and are therefore often considered for use in

ha6ardous areas and environments. )rum skimmers are versatile skimmers and can handle *=

various types of oils ranging from light oils such as diesel to heavier oils such as crude oil.

'9leanup Oil, *++5-

:rush Skimmers


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:rush skimmers can be packaged in a wide range of configurations from stand"alone units to

modules mounted on a barge 'self"floating unit- or on a specially constructed recovery vessel.

)epending on the stiffness and density of the bristles used and the comb configuration,

different types of oil can be recovered. !n general, light oil is better recovered by finer, softer

bristles while stiffer and wider spaced bristles are better suited for heavy oils. '9leanup Oil,

*++5-

:elt Skimmers

:elt skimmers are large and are therefore often mounted on a barge or on a specially

constructed vessel. These skimmers have a high recovery efficiency and good recovery rate,

but are specialised products and can be complicated to operate, which reuires heavy

euipment and specially trained personnel '0OAA, *++-. 2owever, a fi(ed position

mounted belt skimmer reuires an initial tuning but can then operate independently. '0ilsson,

*+5-

0on"Oleophilic Skimmers

Suction Skimmers

Suction skimmers such as vacuum skimmers represent the simplest skimmer design in terms

of operational theory, whereby oil is recovered by air suction systems directly from the water

surface '!TO3F, *+*-. The simplest type of vacuum skimmer uses a hose directly connected

to a vacuum truck, which can easily be employed in harbours or rivers. )ue to the sensitivity

to waves, vacuum skimmers are often restricted to use in harbours and calm waters. '0OAA,

*++- Furthermore, suction skimmers are ideally suited for recovery of oil on or near the

shoreline due to the widespread availability of vacuum systems. 0onetheless, the

undifferentiating nature of the suction device may result in high proportions of water also

being collected. '!TO3F, *+*-

?eir Skimmers


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?eir skimmers refer to skimming devices using gravitational force to drain oil from the

water surface. ?eir skimmers are floating units where the edge of the weir is positioned ;ust

below the upper slick surface or at the interface between the floating oil and water, hence

allowing oil to flow over the weir edge into a collecting sump. The oil is then pumped to

storage tanks. ?eir skimmers are normally launched from vessels using a crane and the weir

can either be remote controlled by compressed air or self"ad;usting. ?eir skimmers are one of

the most commonly used skimmer type due to its simple construction. '0OAA, *++-

'!TO3F, *+*- ?eir skimmers are however prone to be ;ammed or clogged due to floating

debris, and although swell alone does not interfere with skimming operation, weir skimmers

are very sensitive to steep waves '!TO3F, *+*-. !n table *, an overview over different

skimming technologies and their properties are briefly presented.


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OIL SKIMMER WORKING PRINCIPLE

As the :@T rotates, oil adheres to the belt surface separating it from the water. Oil is wiped

from the belt surface and drained into the collection trough. !n a full si6e skimmer the oil

would be pumped or sucked out to a remote containment location.

Floating oil and grease cling to skimming media more readily than water, and water has little

affinity for the media. This allows skimming media in the shape of a belt, disk, drum, etc. to

pass through a fluid surface to pick up floating oil and grease with very little water. This oily

material is subseuently removed from the media with wiper blades or pinch rollers.)esign

of the proposed skimmer


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DESIGN CALCULATIONS

D*0&(&() & &/&() *+&

Stokes’ aw '@uation - defines the rising velocity of oil droplet from the bottom of a

separator to the surface of water. From this euation, the most important variables are the

viscosity of the continuous liuid, specific gravity difference between the continuous liuid,

and the oil droplet si6e. After these are known, the rising velocity and therefore the si6e of

separator reuired may be calculated

?here,

D**'&(&() +*/6(7*7-0*/&8* /*6 /&9*


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D**'&(&() T:;* ! T*(/&( &( B*

B C0T3 D=+/*

?here,

0 B 1otor Speed

T B Torue transmitted by 1otor

D+ '

1otor Spec '1odelE *#A5G+)*, i B $*.-

. >oltage$ *.+>)9

*. Output Speed$ *++ H/" +I 731

5. 0o"oad output current$ BJ + mA

K. 7otation Output$ 9? / 99?

. 0oise$ 0o #ear 0oise

=. Stall output$ $ Slip #ear, :roken #ear is no allowed

G. Output shaft of the a(ial clearance$ BJ +. L +.5mm,

2ori6ontal clearance reuirement BJ +.+ @lectrical Spec

. 0o"oad Speed$ G++ 731

*. 0o"oad 9urrent$ BJ 5+mA

5. 7otation$ 9? K. 1otorE$ 5G+


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S** S**+&( (7 P6*&*/

Sheet :ending process

The euation for estimating the ma(imum bending force is,

,

where k is a factor taking into account several parameters including friction. T is the ultimate

tensile strength of the metal. L and t are the length and thickness of the sheet metal,respectively. The variable W is the open width of a >"die or wiping die.

B* S**+&( (7 66*&*/

9hoosing an Appropriate Skimmer

There are several types of industrial oil skimmers. 9hoosing one best suited for your

application will ma(imi6e oil removal while minimi6ing capital outlay and skimmer

operating costs. First, define the application in terms of the following characteristics$

Operating 9onditions

All skimmers have a moving medium, and possibly other parts, immersed in the liuid. The

performance and life of the pick"up medium, wiper blades, pulleys, etc. are affected by

different conditions. These conditions include temperatures in and out of the liuid, p2 of the

solution, and the presence of solvents or other reactive chemicals.

- 2a6ardous 1aterials$ Applications involving flammable materials or e(plosive vapors

reuire the use of e(plosion proof 'or air driven- motors and controls.

*- Temperature/>iscosity$ All skimmers reuire floating oil to be in a liuid, free"

flowing state. !f the oil congeals or solidifies at ambient temperatures, the tank and/or

skimmer will reuire heaters to maintain fluid flow. This is especially true at

temperatures low enough to free6e water. A heater option is a must if a skimmer is to

be used outdoors in free6ing temperatures.

https://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttps://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttps://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttps://en.wikipedia.org/wiki/Ultimate_tensile_strength


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7emoval 9apacity 7ating

Skimmers usually have an oil removal rate e(pressed in gallons per hour. The rate varies with

oil viscosity and most manufacturer’s rate skimmers using SA@ 5+ weight motor oil at =MF

'NM9-. !f a manufacturer doesn’t specify the test oil for its rating, or your application

involves a much different viscosity, it is wise to ask for additional test data. ?hen specifying

removal capacity, it is better to err on the high side to allow for peaks in the oil influ(.

?ater 9ontent

All oil skimmers pick up some water with the oil they remove. Some designs, particularly

suction skimmers, pick up more water than others. 2igh water content increases oil recycling

and disposal costs. #enerally, the ratio of water"to"oil decreases with thicker films of floating

oil and slower moving pick"up media. An Oil 9oncentrator or decanter installed at the

skimmer discharge port provides secondary oil/water separation that can reduce water content

to nearly 6ero.

7esidual Oil

A skimmer continues to remove oils as long as they are present. )epending on oil influ( rate

and the skimmer’s removal rate, residual oil in the water may be as low as a few parts per

million. ?hen residual oil reaches this level and further reduction is reuired, it may be more

practical to use a secondary removal method following skimming, such as membrane

filtration.

3ortability

Skimmer portability is a plus in some applications. For e(ample, in plants, mobile euipment

service shops, and at remediation sites, a portable skimmer can sometimes service multiple

machines, sumps, or wells.


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T(% S;'6 C,+*&/&+/

The location, shape, and capacity of a tank or water impoundment are ma;or factors in

choosing the right skimmer. Also consider fluctuations in water level, turbulence and possible

emulsions. Although skimmers do not cause emulsions, they can have trouble removing

certain types.

Si6e/)esign$ Oil and water can emulsify when sub;ected to turbulence and other mechanical

agitation. Avoid this by having water return to the tank below the liuid surface at as low a

velocity as practical. 1ake sure your tank or sump provides uiet areas, weirs, and sufficient

volume to allow adeuate time for oil/water separation.

Shape$ Tanks without nooks and crannies for oil to accumulate in are best. !f you have an

irregular shape, put the skimmer where the largest amount of oil accumulates. 9onsider a

means of directing oil towards the skimmer such as a floating boom or baffle plate.

ocation/!nstallation$ The physical location and characteristics of the tank and collection

container are important. )oes skimmed material need to be pumped from the skimmer to the

containerP ?ill skimmer access for periodic maintenance be a problemP 2ow much mounting

space is availableP Are tank or container modifications reuiredP 9heap systems uickly lose

appeal when costs for additional components, increased maintenance and e(pensive tank

modifications are involved.


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LIST OF COMPONENTS

:elt 8 polyurethane

3ulley 8 length " *+mm, dia 8 55mm

Shaft 8 " K+mm 8 *mm dia

:earing 8 !) 8 +mm 8 O) 8 =mm

Structure 8 inch suare rod

:ase 8 mm sheet metal

1otor 8 *v dc motor 8 5++ rpm

9oupler 8 mm dia

7eservoir 8 K+mm ( +mm

?iper 8 ++mm width 8 + mm length


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PROTOTYPING

A scale model of the oil skimmer is prototyped in this pro;ect. The minimum scale must be

$K+ because under this ratio, the surface tension or electro"chemical forces have an effect

that impedes the inertial forces 'pers. comm. )r. >ia;a 7aghavan, *+-.

For the testing of the dimension based on StokesQs aw , $+ is a reasonable scale for the

testing purposes. The real dimensions are = meters ( meter ( +.G meter, therefore the scale

model will be =+cm ( +cm ( G.cm.

The stoke number is the dimensionless measure useful for having a ratio of raising particles

between the prototype and the real scale model.

The corresponding images are shown below.

RRRRRRRRRRRRRRRRRRRR

3@AS@ ATTA92 O7 37OU@9T 32OTOS 2@7@.


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CONCLUSION AND PROPOSAL

!n this pro;ect, we enforced to highlight the function of oil skimmer, its various design

aspects and performance. All the results of e(perimental studies indicate that slight design

improvement of typical oil skimmers towards to include additional belt shaft and use of belt

with steel material instead of rope significantly improve the oil recovery efficiency and also

its structure became simpler. As practical overview of different oil spillage cleanup method.

This 3ro;ect has illustrated several limitations of these methods and current oil spill

technology. Further e(tensive research < testing can improve the e(isting techniues and

euipment to have better control for oil recovery e(ercise.

T6&+ A66&+&(/ 0 I(7;/& O& S%&''*/

?astewater Sumps

1ost manufacturing or processing facilities have circulating water systems. This water

collects in a central tank or sump. 7emoving floating hydrocarbon contamination with little

water content can reduce the cost of disposal and lower the contingent liabilities of

wastewater discharge.

9oolants and 9utting Fluids

?hen machine coolants become contaminated with tramp oils, four things usually occur$

. coolant life is reduced

*. uality of machined parts is reduced

5. in many cases, a smoke will begin to appear in the shop, causing irritation to

the workers on the ;obK. the fluid takes on a %rotten egg& odor. Skimmers that remove tramp oils solve

these problems and typically pay for themselves within a few months.

2eat Treating

Vuench oils that must be removed from heat treated parts can be captured for re"use or

disposal. The results are lower uench oil costs, prolonged wash water life and lower disposal

costs.

3arts ?ashers


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Floating oils re"contaminate parts as they are removed from a wash tank. Oil skimmers can

remove this oil. The benefits of using an oil skimmer are oil"free parts and e(tended fluid life.

Food 3rocessing Facilities

7emoval of vegetable oils, greases, and animal fats from a plant’s wastewater stream reduces

the costs of processing and disposal.

3arking ots, #arages and Service Facilities

?aste oil from leaks, spills and other sources must be retrieved from sumps before water can

be discharged to storm or sanitary sewers. Outdoor 3onds, akes, :asins, @tc. ?here floating

oils are present, skimmers provide ine(pensive and effective removal, solving a serious

environmental problem.

7ecovery/1onitoring ?ells

7emoving oil, fuel and other hydrocarbon liuid from wells can be more cost"effective using

a belt skimmer instead of a down well pump. Skimmers don’t have nearly the maintenance

issues and can reach depths of ++ feet or more, removing product despite fluctuating water

tables. Skimmers can handle very thick fluids effortlessly and some 'like the Abanaki

3etroWtractor- can separate some )0A3’s such as coal tar and creosote from water.


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REFERENCES

XY Z>ictoria :ro;e’ and ZArturo A. 4eller’, % !mprovedrecovery of oil spills from water

surfaces using tailoredsurfaces in Oleophilic skimmers, )onald :ren School of

@nvironmental Science < 1anagement, niversity of 9alifornia, Santa :arbara.

X*Y ZAST1.*++G.AST1 FG*="+=’, %Standard test methods for sorbent performance of

adsorbents&, American society of testing and materials, ?est 9onshohocken.3.A.

X5Y 7.S. 4hurmi and U.4.#upta, 1achine )esign"[, S chand

XKY 4 Subhramanya, Fluid 1echanics and 2ydraulic 1achines, Tata 1c#raw 2ill '*+*-

XY ZS.2. Schwart6’, %3erformance tests of four selected oil spill skimmers, in$ 3roceedings of

the !nternational Oil Spill 9onference&, American 3etroleum !nstitute, ?ashington, )9,

SA, \G\, pp. K\58K\=.

X=Y ZS.). #ill, ?. 7yan’, %Assessment of the A9?"K++ oil skimmer by the 9anadian 9oast

#uard for oil spill countermeasure operations, in$ 3roceedings of the !nternational Oil Spill

9onference&, American 3etroleum !nstitute, ?ashington, )9, SA, \G\, pp. *G\8*N*.

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