Contents ACKNOWLEDGEMENT ............................................................................................................................ 3

ABSTRACT .................................................................................................................................................. 4

DECLARATION .......................................................................................................................................... 5

1. INTRODUCTION ............................................................................................................................... 6

1.1 Background Information ............................................................................................................ 6

1.2 Process Summary ........................................................................................................................ 7

1.3 Problem Identification ................................................................................................................ 9

1.4 Problem Definition – Heavy Fuel Oils ..................................................................................... 11

1.4.1 Physical Properties ............................................................................................................ 11

1.4.2 Chemical Composition of Heavy Fuel Oils ..................................................................... 12

1.4.3 Analysis of Individual Components of HFOs on the environment ............................... 13

1.5 Justification: The Dangers of Using Heavy Fuel Oils in boilers................................................. 15

1.5.1 Environmental Problems .................................................................................................. 15

1.5.2 Economic problems ........................................................................................................... 19

1.5.3 Legal issues ........................................................................................................................ 21

2. DATA COLLECTION ..................................................................................................................... 23

2.1 Observation ............................................................................................................................... 23

2.2 Analysis of technical manual .................................................................................................... 23

2.3 Interviews with Plant personnel .............................................................................................. 24

2.4 Analysis of industry and personal reports written by industry experts ............................... 24

2.5 Internet Research ...................................................................................................................... 24

3. RESULTS .......................................................................................................................................... 25

3.1 From observations, the following results were attained ........................................................ 25

3.2 From the technical manual ....................................................................................................... 25

3.3 From interviews with Plant personnel ........................................................................................ 26

4.0 SOLUTIONS ................................................................................................................................. 27

4.1 Replace the Fuel being used in the boiler................................................................................ 27

4.2 Replace the boiler ...................................................................................................................... 29

4.3 Exhaust scrubbing .................................................................................................................... 30

2

4.3.1 The Scrubbing process...................................................................................................... 31

5. Analysis of Solutions ......................................................................................................................... 36

5.1 As far as switching the type of fuel used in the boiler is concerned: ................................................ 36

5.2 When it comes to buying of a new boiler: ........................................................................................ 36

5.3 Installing an exhaust gas scrubbing system: ..................................................................................... 37

5.4 CONCLUSION ......................................................................................................................... 40

5.5 RECOMMENDATIONS .......................................................................................................... 40

5.6 References .................................................................................................................................. 41

3

ACKNOWLEDGEMENT

From Odada Charles A.

I would like to start by thanking the Almighty for having opened the right doors for me and for

having given me the opportunity to be here and to successfully complete my industrial

attachment.

Next I would like to thank the staff and the administration of Equator Bottlers giving me the

opportunity to be on attachment here. I would also like to thank them for the learning

opportunities and the lessons that they have taught me during my attachment. The valuable

experience I have acquired through them will forever remain with me.

I would also like to thank my entire family and friends for the support that they have given me in

various ways during my attachment.

I would like to acknowledge the entire staff of Moi University School of Engineering,

Department of Mechanical and Production especially the Head of Department, Eng. Chebii,

Attachment Coordinator, Mr. Njoroge and other staff for providing the necessary support from

the time of identifying the attachment station up to the end of the industrial attachment.

4

ABSTRACT

This report contains a description and an analysis of the pollution problem that is posed by the

use of Heavy fuel oil in boilers. The context of this analysis is on the boiler currently in user at

the Equator Bottlers plant in Kisumu. The impact of the pollutants on the workers and other

people is presented. The impact of the pollutants on a lake environment is also discussed with

consideration to the proximity of the plant to Lake Victoria.

Possible solutions to the problem have also been presented including diagrammatic

representations of how these solutions can be achieved. The scientific backing that proves the

viability of these solutions is presented. Factors that bear impact to the solutions such as cost,

manpower and overall viability have been taken into account.

5

DECLARATION

I Odada Charles A. declare that this is wholly and fully my original work and has never

been presented to any institution for the award of a Bachelor’s Degree in Mechanical and

Production Engineering or any other related award and shall never be reproduced without the

authority of Moi University or myself.

STUDENT

Sign …………………………………….

Date …………………………………….

6

1. INTRODUCTION

1.1 Background Information

Fig. 1: The Coca-Cola logo

Equator Bottlers Limited (EBL) is a franchise of the Coca-Cola Company and is located about

five kilometers out of Kisumu, Kenya. Equator Bottlers Limited is the company with the

mandate to supply Coca-cola and all beverages associated with the Coca-cola company to

Kakamega, Vihiga, Kericho, Bomet, Siaya, Busia and Kisumu Counties in Kenya. Like all other

bottling plants in Kenya and the rest of the world, Equator bottlers only mixes the concentrates

received from the Coca-cola company. The magnitude of the bottling process is however not

negligible and a company structure has been carefully developed so as to facilitate the entire

bottling process from the inception to the selling of the final product to consumers.

This same magnitude also means that the company’s actions no matter how small will have a

much larger impact than will be immediately observed. This is especially important to note since

EBL operates in the vicinity of a lake ecosystem which is a major food provider in the region and

is also a source of employment for a good number of the inhabitants of the city of Kisumu either

directly or indirectly.

7

1.2 Process Summary

The main bottling process takes places as follows:

1. Warehouse: Pallets carrying crates of empty bottles are taken from the warehouse to the

depalletizer where they are placed on top of rollers.

2. Depalletizer: Removes the crates from the pallets and places them on top of conveyor

belts.

3. Unpacker: The crates arrive by conveyor and the unpacker takes the empty bottles from

the crates and places them on another conveyor belts. The crates are then taken to the

crate washer.

4. Bottle washer: The bottle washer through a series of steps cleans and disinfects the

bottles before placing them on another conveyor belt

5. EBI: The Electrical Bottle Inspector (EBI) inspects passing bottle for any faults such as

breakage, presence of water and/or caustic or color.

6. Mixer: This is where the concentrate is mixed with the syrup, carbon dioxide and water to

produce the final soft drink.

7. Filler: Fills the empty bottles with the soft drink

8. Crowner: Puts the crowns on the filled bottles

9. Packer: Picks the filled bottles from the conveyor and places them into clean crates from

the crate washer.

10. Palletizer: Picks the crates from the conveyor belts and stacks them on pallets.

11. Warehouse: The pallets holding the filled crates are carried by forklifts to the warehouse

to await transportation to the customers.

8

Apart from the primary production system, there are also several facilities that provide support

services that impact on the production either directly or indirectly. These facilities include:

a) The Boiler: Most of the production machines are pneumatic and the boiler provides the

steam that is required to operate these systems.

b) The Compressor: Ensures the steam that goes to production is at the right pressure.

c) The Generator: Provides electricity to the plant in case of blackouts.

d) Water Treatment: Ensures that the water that is used for production, cleaning and other

purposes is of the right quality. The water received from the tanks must pass through the

water treatment section before going into production.

e) The Chiller: Is used to cool the glycol (70% water, 30% glycol) that is subsequently used

to cool the soft drinks in the mixer.

f) Waste water treatment plant: Treats all the waste water from the production portion of the

plant before it is discharged to KEWASCO (Kisumu Water and Sewerage Company).

g) Syrup room: This is where the syrup consisting mainly of fine sugar and water is

prepared before it is pumped to the mixer where it is mixed with the concentrate, water

and carbon dioxide.

h) Quality Control: The quality control section is vital to the operation of the plant. The

quality control section ensures that the soft drinks produced conform to the health and

safety standards that have been set both by the ministry of health and the parent Coca-

cola Company. Tests are conducted on random samples of water, bottles, soft drink and

other things that affect the production process.

9

1.3 Problem Identification

A boiler is a closed vessel in which water or any other fluid is heated. The vaporized fluid exits

the boiler for use in various applications. In equator bottlers, the steam is used to run the

pneumatic machines that are used in the bottling process. The most important thing in a boiler is

the source of heat. Different fuels are usually used in boilers including but not limited to wood,

coal, oil and natural gas.

Boilers are a great solution to a wide variety of engineering problems. When water is heated and

vaporized it can expand to nearly 1000 times its initial size and can move through pipes at speeds

nearing 100 kph. This makes steam an excellent way of transferring of energy and this is the

principle that is used to operate machinery, run fossil fuel and nuclear power plants and do many

other things. This has also made boilers an integral if not vital part of most industries. Companies

ranging from small scale agricultural firms to large scale power plants make use of boilers to

achieve most of their functions. The use of boilers can in many ways be measured up to the use

of automobiles. Just like their mobile counterparts, the use of boilers has become synonymous

with greater industrialization. In many ways, the number of boilers used within a particular area

can be said to be a measure of how industrialized the area is.

However, just like cars the widespread use of boilers has brought with it another concern; that of

pollution. While it might be said that the number of boilers in no way compare to cars, this in no

way means that the potential of boilers to cause pollution is much less. Since boilers are mostly

stationary or at best slow moving members, this permits them to use varieties of fossil fuels that

are heavier in terms of density. These fuels are primarily made up of long chain hydrocarbons

10

such as alkanes and cycloalkanes. These fuels are obtained much later from the petroleum

distillation process as compared to other products of oil refinery such as LPG and petrol.

Fig. 2: Petroleum distillation process

Fuel is much more viscous than most other products of the refining process. This means that

before it is used, the oil must first be heated to reduce its viscosity. Since these fuels have little

use in mobile systems, their demand is much less and this makes them much cheaper and more

commercially viable to use in systems such as boilers where fuel is consumed in large quantities.

The main reason however that makes HFO particularly cheap is the fact that it is heavy on

pollutants. Since HFO is cheap and heavy on pollutants, there is increased use of this type of fuel

11

in many industrial a factor that ensures that maximum pollutants are always being released into

the atmosphere.

1.4 Problem Definition – Heavy Fuel Oils

1.4.1 Physical Properties

Photo 1: Physical Characteristics of HFO

Heavy fuel oils are blended products based on the residues from various refinery distillation and

cracking processes. They are viscous liquids with a characteristic odour and require heating for

storage and combustion. Heavy fuel oils are used in medium to large industrial plants, marine

applications and power stations in combustion equipment such as boilers, furnaces and diesel

engines.

Heavy fuel oil is a general term and other names commonly used to describe this range of

products include: residual fuel oil, bunker fuel, bunker C, fuel oil No 6, industrial fuel oil, marine

fuel oil and black oil. These fuels differ in character from straight run fuels in that the density

12

and mean molecular weight are higher, as is the carbon/hydrogen ratio. The density of some

heavy fuel oils can be above 1,000 kg/m3, which has environmental implications in the event of

a spillage into fresh water.

Heavy fuel oil is practically unusable in the form in which it is obtained from the petroleum

distillation column. Therefore it must first be converted into a form that makes it suitable for

handling and storage in industries and marine applications. There are also specifications that

have been put in place for any blend of fuel oil that is meant to be put on the market. To achieve

these properties, the fuel oil is usually blended with gas oils or other distillations fractions that

have a much lower viscosity. If a refinery has a catalytic cracking unit then catalytically cracked

cycle oils will most likely be used to dilute the heavy fuel oil. The fact that there are so many

ways of diluting the heavy fuel oil to give it the desired viscosity also means that the

composition of the heavy fuel oils can vary widely.

1.4.2 Chemical Composition of Heavy Fuel Oils

Heavy fuel oils are highly complex mixtures and are made up of compounds with high molecular

weights. The typical boiling range for HFOs is 350 to 650 degrees Celsius. HFOs consist of

aromatic, aliphatic and naphthenic hydrocarbons. These have very long carbon chains ranging

from 20 to 50. They also contain asphaltenes and smaller amounts of heterocyclic compounds

which contain Sulphur, Nitrogen and Oxygen.

Due to their presence in the original crude oils, organo-metallic compounds will also be present

in Heavy fuel oils. Of these, Vanadium is the one that is of most significant when it comes to

pollution. Other elements that occur in heavy fuel oils include nickel, iron, potassium, sodium,

aluminium and silicon. Aluminium and silicon are mainly derived from refinery catalyst fines.

13

There has also been found significant amounts of hydrogen sulphide in the headspaces of storage

tanks that contain heavy fuel oils.

1.4.3 Analysis of Individual Components of HFOs on the environment

Sulphur

By far, sulphur is the most worrying component of heavy fuel oils. All liquid products of oil

distillation contain a certain amount of sulphur but the position of heavy fuel oils in the

distillation process ensure that HFOs contain more sulphur than other liquid fuels such as

kerosene. The percentage of sulphur by weight in HFOs ranges from 1% to 4%. While the

emission of certain pollutants such as oxides of nitrogen, carbon monoxide and soot can usually

be controlled by modification of the combustion, practically all the sulphur present in the HFO

will also be present in the exhaust fumes.

Elemental sulphur is not harmful to human beings or the natural environment. However, in

boilers sulphur exists extensively as Sulphur dioxide which is emitted in the exhaust after the

combustion. A small percentage of the sulphur will also be found in Hydrogen sulphide which

occasionally accumulates in the headspace of fuel tanks used in the storage of HFOs. The

hydrogen sulphide in this case is usually evolved when the HFO is heated to improve its

properties before combustion. Sulphur dioxide comes about as a result of the combustion system

as the sulphur present in the HFO combines with oxygen to form the gaseous compound.

Nitrogen

In HFOs, nitrogen is found as part of heterocyclic compounds. The nitrogen in these compounds

is released when the HFOs undergo combustion. However if the combustion temperatures are

high enough as is the case in most boilers, the nitrogen will quickly combine with oxygen to

form various oxides of nitrogen. The usual products are Nitric oxide (NO) and Nitrogen dioxide

14

(NO2). Nitric Oxide and Nitrogen dioxide are notorious pollutants of the lower atmosphere and

directly impact the quality of the air that is breathed. Nitrogen can also exist in the form of

Nitrous oxide (N2O), a known greenhouse gas.

Trace metals

Vanadium is the trace metal that is of most significance in HFOs. The quantity of Vanadium in

HFOs greatly varies depending on the origin of the original crude oil. For example it has been

found that crude oil sourced from around Mexico and the Caribbean are particularly high in

vanadium.

Nickel, magnesium, aluminium and copper plus other metals are also quite common in heavy

fuel oils. There composition of metals varies greatly according to the region from which the

crude oil was acquired. These metals either change to a gas phase and are emitted with other

gases from the exhaust stack of the power plant or adhere to fine particles are also emitted to

atmosphere.

Carbon

Carbon along with hydrogen is a primary component of all petroleum fuels. In most cases carbon

is not considered a pollutant. If however the fuel oil is not properly combusted, the carbon may

fail to burn properly giving rise to excessive soot (small dark particulate matter) and may also

result in the evolution of carbon monoxide. The problem of carbon as a pollutant is however

easily controlled by proper control of the combustion process thus it shall not be tackled in this

particular report. It should however be noted that even the safest product of fuel combustion i.e.

carbon dioxide is also a greenhouse gas.

PAHs – Polycyclic aromatic Hydrocarbons

15

Polycyclic aromatic hydrocarbons (PAHs) are potent atmospheric pollutants that consist of fused

aromatic rings and do not contain heteroatoms or carry substituents. PAHs are found in all fossil

fuels but like sulphur it is more present in heavy fuel oils than most other products of the oil

refining process. There are more PAHs in HFOs than would normally be found. This is because

heavy oil is blended with cracked and uncracked hydrocarbon residues. Thus HFO may have as

much as 5% PAHs in total.

1.5 Justification: The Dangers of Using Heavy Fuel Oils in boilers

1.5.1 Environmental Problems

Similar to all liquid fossil fuels, heavy fuel oils contain a variety of components that are quite

toxic to the environment. Heavy fuel oils contain most of these pollutants in much greater

portions than the other liquid fuels and this makes its use even more questionable. Some of the

most notable pollutants in heavy fuel oils are:

- Sulphur

- Nitrogen

- Particulates (or particulate matter)

- Polycyclic aromatic Hydrocarbons

Sulphur

Sulphur is the chief pollutant in fossil fuels and it is the one that causes the greatest amount of

worry. The sulphur content of an average Heavy fuel oil can range from 1% to 4% of the fuels

weight.

As previously discussed, almost all the sulphur present in the initial fuel oil will be present in

the exhaust. The sulphur will most likely be in the form of sulphur dioxide (SO2). Sulphur

dioxide dissolves in water vapour to form sulphuric acid. From this perspective alone, sulphur

16

dioxide has been noted to contribute greatly in respiratory illnesses in children and the elderly. It

has also been found to aggravate existing heart and lung conditions. These problems are likely to

affect people who work with or live near a HFO boiler. The casualties may be more if the wind

conditions are right.

On a much wider scale, this sulphuric acid in the atmosphere later falls as rain and this is what is

commonly referred to as acid rain. Acid rain is one of the most destructive environmental

phenomena. It causes extensive damage to crops.

This may be due acid rain or gaseous uptake, the damage can be;

•Necrosis–killing of tissue or destruction of leaf tissue

•Chlorosis–loss or reduction of chlorophyll

•Epinasty-is the downward curvature of leaf due to high rate of growth on the upper surface

•Leaf abscission–dropping of leaves

–The gaseous uptake of SO2by vegetations results;

•Internal cellular damage or

•Changes to biochemical /physiological processes

Acid rain also has the same acidifying effect on the water bodies such as lakes it can end up

killing the organisms in the water. This is of particular concern since the coca-cola plant is right

next to the lake.

Building materials are subject to weathering decay (deterioration) under the action of

meteorological factors such as precipitation, wind, and solar radiation. However, the presence of

air pollutants – including acid aerosols and their precursors – can damage or accelerate the aging

of building materials. Damage to building materials over time by exposure to sulphur pollution

17

can represent a burden on the economy of industrialized nations (Nriagu, 1978). This damage

can occur in the form of deterioration, corrosion, and staining.

Apart from buildings, acid rain also causes extensive damage to most metals. This is of particular

concern due to the extensive use of iron sheet roofing in and around Kisumu. Acid rains causes

and aggravates corrosion of most metals and this means even buildings with steel members are

likely to experience a reduced life span.

SO2 also reacts with other chemicals in the air to form sulphate particles. Apart from respiratory

problems, sulphate particles are the main cause of reduced visibility which is usually experienced

in heavily industrialized places.

Nitrogen

Despite being able to be controlled by careful monitoring of the combustion, there is always a

certain quantity of oxides of nitrogen being released into the atmosphere. Nitrogen dioxide is the

most common of these oxides and this is a problem because Nitrogen dioxide is a primary irritant

and chronic exposure to elevated levels can lead to increased incidence of acute respiratory

diseases in children and lower resistance adults.

Nitrogen dioxide is also highly soluble in water. When released to the atmosphere it dissolves in

the vapour to for Nitric Acid (HNO3). Nitrogen is one of the two major acids in acid rain

together with sulphuric acid. The dangers of acid rain have already been discussed above.

Nitrate can also react in the atmosphere to form nitrate aerosol particles, these also causes;

–human cancers and

–Impairing visibility

18

Particulate Matter

Particulate matter is a general term that is used to describe solid particles or liquid droplets that

are suspended in air. The composition of particulate matter produced varies according to the fuel

quality, source and other factors. The presence of certain organometallic components will cause

a much more dangerous particulate type of particulate matter.

Generally, ambient PM have the following impacts;

–Chronic bronchitis

–Aggravation of respiratory and cardiovascular diseases.

The PM of heavier fuels such as diesel and HFOs have been linked to lung cancer and are said to

be a possible cause. PM also cause a reduction in visibility and can aggravate asthma.

Polycyclic aromatic hydrocarbons (PAHs)

Many PAHs have been identified as being carcinogenic to both human being and animals.

PAH’s are difficult to break down and when combusted are partially released to atmosphere

creating carcinogenic air emissions. They are present in the heavy oil in high concentrations and

can survive the combustion process where they migrate and adhere to fine particles and ultrafine

particles known as PM10 and PM2.5 respectively (the 10 and 2.5 refer to the size of the particles

in microns).

PM2.5 is especially dangerous as the ultrafine particles have been found to penetrate deeply into

the lungs of humans and cause damage to the respiratory system. These particles may or may not

have contaminants adhered to them. If they do have contamination present or if they are particles

of toxic material such as nickel dust then the contaminants are believed to be able to cross the

tissue barriers in the lungs to the blood carrying the toxins with them.

19

It should also be noted that Heavy metals and PAH’s have a tendency to bioaccumulate up

through the food chain with shellfish passing their toxic burden on to the fish and birds that eat

them. In turn humans eating these fish or birds (or shellfish) will be exposed to the cumulative

toxic loads that have built up in these creatures.

Dioxins and Furans

One of the most toxic substances ever assessed is polychlorinated dibenzo-pdioxins and

dibenzofurans (PCDD/ PCDF) - also known as dioxins and furans. Dioxin and furans are

extremely toxic even at extremely trace levels. These toxins are unintentionally created by

combustion of carbon and chlorine together. Brominated dioxins and furans are created by

burning carbon and bromines (including salts) together. Dioxins and furans are some of the most

toxic persistent organic pollutants (POPs). Dioxins persist in the environment for long periods of

time contaminating soils around point sources such as HFO boilers and biomagnifying through

the food chain until they reach humans where they deposit in the fatty deposits in the body.

1.5.2 Economic problems

Despite its perceived cheapness, HFOs might eventually prove to very expensive to the plants

that use them.

1. For starters, boilers that run on HFOs will require very heavy maintenance on a regular

basis. HFOs are sold to plants in a very dirt form that is practically unusable in the boiler.

The HFO must thus be passed through several heavy filters before they eventually find

their way into the burner of the boiler. As observed during maintenance of the boiler at

equator bottlers, the cleaning of these filters is an extremely dirty job as a lot of slimy

deposits have to be removed. The HFO also has a very pungent smell that makes the job

even less desirable. The regular maintenance is an economic problem because it causes:

20

- Production downtime as the boiler has to be shut down before maintenance

- Use of extra manpower to perform the maintenance. Due to the sensitive nature of the

burner assembly and other parts, there must be a skilled hand performing the maintenance

to avoid any errors.

- High cost of materials used during the maintenance process.

2. Apart from maintenance, the presence of sulphur dioxide (SO2) in HFO and its exhaust

may be cause corrosion of the internal parts of the boiler if it mixes with water which is a

common contaminant in HFO. Corroded boiler parts result in high maintenance and

replacement costs and also further the risk of boiler explosion. This is because a

weakened metal structure may fracture. A fracture is a weak point that can undoubtedly

compromise the whole boiler.

3. Another problem in using HFO is the accumulation of H2S in the upper parts of the

storage tank. Accumulation of H2S is dangerous to boilers because it is a highly

flammable gas and it furthers the risk of an explosion. The gas also carries a bad odour

that makes it difficult to work around. The easiest way to prevent this accumulation of

H2S is to keep the storage tanks of HFOs constantly full. It is however a rather

challenging and expensive thing to keep a fuel tank full around the clock.

4. The use of a fuel with heavy pollutants such as HFOs will eventually portray a bad image

for the company. In a time when environmental consciousness is as a powerful public

relations tool, it is important for the company to consider how its activities impact the

environment. Lack of environmental consciousness can cause a boycott of the company’s

products and this might result in severe losses. Coca-cola is a world recognised brand and

its affiliation with the destruction of the environment is unacceptable.

21

1.5.3 Legal issues

The polluting capacity of heavy fuel oils has not gone unnoticed. HFOs have become a major

talking point mainly because of their extensive use in large ships, power plants and in industries.

Heavy fuel oils have been noted as being one of the dirtiest fossil fuels that are currently in use

and this may present the following legal issues.

International Statutes

- While the use of HFOs in developing countries is widespread and usually considered to

be more technologically advanced when compared to funnel fuels such as wood and coal,

its use is being increasingly regulated in the developed countries. However, due to shared

airspace, water ways and water bodies the effects of pollutants are not restricted to the

countries that are responsible for producing them. Strong winds can carry airborne

pollutants and acidic rains many kilometres from their origins and strong currents will do

the same for waterborne pollutants.

- Pollutants that accumulate up the food chain are also a concern as their effects can also be

felt much further away.

- Due to this reason, most developing countries that are associated with producing,

refining, transporting or selling HFOs are adopting very stringent regulations that are

aimed at directly curbing the use of HFOs. Some of these legislations are being discussed

while several have been passed setting benchmarks that are aimed at reducing pollution

on a global scale.

- This increased legislation against HFOs means that in the near future the cost of these

fuels in the market will be significantly higher due to taxes imposed on transporters,

refineries and other related parties.

22

- There is also the increased likelihood of a ‘carbon tax’ being introduced which will be

aimed at taxing specific companies on the level of pollution that they cause.

- To equator bottlers, this means that the operating levels in the future will likely go up.

Should the company find itself completely dependent on HFOs, it may find it hard to

cope.

Bad Precedents

One of the main reasons why the pollution caused by equator bottlers is of concern is the bad

precedent that it sets for other industries. The recent introduction of an international airport in

Kisumu means that there is likely to be an increase in human traffic. This will likely cause an

increase in the number of industries in the city. This increase of industries is expected and is one

of the primary reasons for the upgrading of the airport.

When these industries start, they will most likely required to work from the ‘blueprint’ or the

precedent of a company that already operates in the area and has registered significant success

already. Due to the fact that coca-cola is a global brand, equator bottlers is one of the companies

that will be chosen as a good blueprint by these other companies.

The effect of pollution caused by the boiler at equator bottlers has not yet been felt mainly

because it is only one of a few industries that make use of such systems in the area. If these new

companies also adopt the same polluting systems that equator bottlers uses then the cumulative

effects of the pollution caused by all these companies will definitely be felt and all the problems

of pollution described above such as acid will be felt to full effect. As a bottler for a global

brand, equator bottlers has a mandate to set a better example for future companies.

23

2. DATA COLLECTION

The data collection methods that were employed to collect the information were:

1. Observation

2. Analysis of technical manual

3. Interviews with plant personnel

4. Analysis of Industry and personal reports written by industry experts

5. Internet Research

2.1 Observation

The general operation of the boiler was observed during its working days to monitor the ignition

process, the burning and the exhaust gases. Of particular interest was the colour of the exhaust

plus the presence of any residual fumes and odours in the air. The best observation could only be

done during maintenance. This was when the physical properties of fuel oil could be observed.

This is because during normal operation the fuel comes in by tanker and pumped directly into the

storage tanks from where it is fed by pipes to the boiler. This means that the fuel properties can

only be observed during maintenance when some of the fuel has to be drained to enable cleaning

of the filters.

2.2 Analysis of technical manual

The boiler was purchased with a manual. The manual proved to be a source of information of all

the various parts that make up the boiler and how they work to effectively burn the fuel. The

manual also contained a list of additives that are supposed to be added to the fuel before use.

Apart from this the technical manual also had information detailing the specifications with which

relevant structures to pollution such as the chimney was to be built.

24

2.3 Interviews with Plant personnel

Most of the information acquired from the technical manual represented an ideal situation. There

is however no assurance that the company would stick to the requirements and specifications that

have been stated in the manual. For this reason, interviews were carried out with the relevant

plant personnel to attain information giving the exact details on the fuel used, the boiler and

whether or not specifications mentioned in the boiler were adhered to.

2.4 Analysis of industry and personal reports written by industry experts

Reports written by industry experts acquired from previous analysis of heavy fuel oils proved to

be useful in attaining information on the effects of the use of these fuels. These are tackled

further in chapter 3(literature review).

2.5 Internet Research

Research sites such as Wikipedia were a source of valuable information on the general nature of

boiler and the nature of the fuels used within.

25

3. RESULTS

3.1 From observations, the following results were attained

1. The exhaust from the boiler’s burner is mostly clear except for a few situations such

as during start up or if the HFO has been contaminated.

2. There is no mechanism or structure that is in place to perform any scrubbing of the

exhaust before it leaves the boiler.

3. During maintenance, the filters found to have an excessive layer of slime on them.

The level of cleaning required was quite extreme and a lot of resources and

manpower had to be employed.

3.2 From the technical manual

1. The makers of the boiler don’t provide or recommend any sort of mechanism to scrub or

clean pollutants from the exhaust.

2. The boiler’s chimney is built according to specifications that have been dictated in the

Indian standard specification IS:6533.

3. The Indian standard specification doesn’t make any provisions or recommendations for

scrubbing the exhaust gasses that pass the chimney.

4. The boiler’s technical manual does provide for an additive that can be added to improve

the quality of the fuel. Thermosol is a brand of additives provided by the company that

manufactured the boiler (Shell Petroleum) and its main purposes are to:

a) Prevent fuel polymerisation i.e. the formation of long hydrocarbon chains

b) Disperses sludge

c) Aids water removal and prevents corrosion of tanks and fuel lines.

d) Restricts formation of waxy deposits

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e) Improves atomisation due to reduction in surface tension

f) Improves combustion and minimises corrosion due to SO3

N/B: While this additive reduces the amount of pollutants that are produced by improving

the ignition qualities of the fuel, it doesn’t deal with the most persistent and dangerous

pollutants such as sulphur dioxide and it doesn’t prevent these pollutants from leaving in

the exhaust.

3.3 From interviews with Plant personnel

a) The personnel were of the opinion that the fuel used was of the poorest quality since its

ignition qualities were poor and so were its physical properties.

b) The personnel also seemed to believe that no additives were used in the fuel despite

the recommendations in the technical manual.

3.4 From reports written by industry experts,

a) The polluting effects of heavy fuel oil are such that they can no longer be ignored.

Extensive experiments carried both on the fuel and in places where the fuel is in heavy

use have revealed that the fuel can drastically change the environment and biosystems in

its locality. If the use of the fuel is heavy enough such as in a large scale power plant then

polluting effects will likely be felt even in places far from the source of the pollutant.

This is the main cause of the aggressive legislations that are being passed in many

developed countries that will in the near future see a heavy price being put on the use of

heavy fuel oil all over the world.

Most industry experts are of the opinion that extensive use of HFOs is what has

contributed in large part to the rise in cancer cases in the last half century and some of

their most adverse effects are yet to be discovered.

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4.0 SOLUTIONS

The problem of pollution is not unique. It has been encountered many times before and various

solutions have been employed to deal with it. In the case of equator bottlers, the solutions will

have to consider:

1. Financial viability

2. Location

3. General applicability of the solution

4. Long term effects of the solution

5. Time required to apply the solution

There are three possible solutions that can be applied to this particular problem. Each of these

solutions will deal with the problem of pollution that arises from using HFOs.

4.1 Replace the Fuel being used in the boiler

The boiler in user at equator bottlers is a shellmax 3-pass smoke tube full wet back boiler. It can

be fired on either liquid or gaseous fuels. It is suitable for burning both waste gases and fluid

fuels together when fitted with a special burner. This basically means that the boiler is capable of

running on a variety of fuels namely:

- Fuel oils

- Low sulphur heavy stock (LSHS)

- Light oil

- Natural gas

It can be seen that the boiler itself provide a good number of options for anybody who is seeking

to reduce the damage done to the environment. LSHS, light oil, and natural gas are all cleaner

options for the boiler than heavy fuel oils. Natural gas is by far the cleanest choice. Switching to

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natural gas will ensure that the boiler inflicts almost no harm to the environment because

combustion of natural gas gives out only heat, carbon dioxide and water. This is because natural

gas is mostly made up of methane which is only made up of carbon and hydrogen. A smaller

percentage of natural gas might consist of other hydrocarbons but these are usually in negligible

quantities.

Fig. 3: Reaction of methane and oxygen

Lighter fuel oils such as diesel also provide a solution of their own. Most of these light oils

contain much less sulphur than the heavy fuel oils. This means that there will also be much less

sulphur in the exhaust and this will reduce the danger to the environment. Lighter fuels also have

much better ignition properties and higher octane ratings. This means that much less fuel will

need to be burned so as to produce the same quantity of heat that would be provided by a greater

volume of HFO.

Low Sulphur Heavy Stock (LSHS) is a residual fuel processed from indigenous crude. This fuel

is in lieu of FO in the same applications where furnace oil is suitable. The main difference with

LSHS and FO is in the form of higher pour point, higher calorific value and lower sulphur

content in LSHS. This means that as far as pollution is concerned, it is a much better option than

Heavy fuel oil.

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4.2 Replace the boiler

Replacing the boiler will enable the company to get the exact kind of boiler that they want. This

will reduce the problem of having to reconfigure the current boiler to suit the needs of a new

kind of fuel. This is the solution that the company seems to be currently undertaking. While the

heavy fuel oil boiler offers a variety of options as far as fuel is concerned, it doesn’t offer enough

options as far as clean fuel is concerned. There are many more boilers that use fuels that are far

much cleaner than any of the fuels used in the boiler such as electricity.

a) Electricity is the cleanest and most dependable type of energy that can be used. If the

electricity is acquired from a hydroelectric or a geothermal source then the energy can be

said to be clean from the source to the application and poses no threat to the environment.

b) There are also solar boilers currently being researched and several already on sale. Solar

boilers are also sure to provide clean boilers since they take energy directly from

sunlight. A solar boiler would also be particularly suited to the environment in Kisumu.

Kisumu is well known for its high temperatures especially around high noon and there is

plenty of sunlight here to operate such a boiler.

c) Boilers that run on biomass are also quite common these days. Biomass is derived from

plant material that is acquired without doing any damage to the natural environment. Cow

dung is also a good source of biomass and it has been used for heating purposes for quite

a while.

d) The advantage of changing the boiler is that it will enable the company to think beyond

the problem of solution only. While the pollution is the most obvious problem there are a

number of recurring problems that are dealt with during maintenance. If the boiler would

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be replaced then these problems will be much more easily addressed to ensure that the

new boiler has much fewer problems to deal with at any given time.

4.3 Exhaust scrubbing

The polluting effects of heavy fuel oil have haunted the world for a while. This problem

is also shared with the polluting effects of most fossil fuels. However, the biggest

problem that the world has faced so far is that despite all the negative effects of fossil

fuels, the world is yet to find an energy source that could come even close to replacing

these fuels.

The world has become highly dependent on fossil fuels in very many areas from the

transportation industry to power generation and even to run boilers in industry. While

electricity does offer a viable solution, this option is still quite expensive in most

countries including Kenya. This is mainly because electricity still costs a lot of money to

produce and in many cases it is the same fossil fuels that are used to produce this

electricity. The infrastructure required to set up a source of electricity that is clean such as

a hydroelectric or geothermal power station cost a staggering amount of money and is

dependent on the presence of geographical features such as rivers and hot springs.

This means that as things stand, heavy fuel oil is a much cheaper option, one that is

almost irreplaceable to the company and thus their best option is currently exhaust gas

scrubbing.

Exhaust gas scrubbing involves the use of a scrubber which is group of air pollution

control devices that can be used to remove some particulates and gases from industrial

exhaust streams. Scrubbers are one of the primary devices that control gaseous emissions,

especially acid gases and are in use in many systems all over the world. Scrubbers are

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used in many developed countries in industries that are still dependent on fossil fuels

because there are many laws that have been set in order to control pollution.

Scrubbers are also widely employed in power plants that are primarily powered by fossil

fuels such as diesel and heavy fuel oils. These plants produce a large amount of pollutant

gases and without these scrubbers the effect on the environment even in the short term

will be great.

The use of heavy fuel oils in ships is becoming increasingly regulated and for this reason,

these scrubbers are already being employed in the large ships such as ocean liners.

4.3.1 The Scrubbing process

The process of exhaust gas scrubbing is not one but a series of steps that are designed to remove

various pollutants from the exhaust gases before the gases are released into the atmosphere. The

quality of fossil fuels especially heavy fuel oil varies greatly depending on the source and other

factors. For this reason there is rarely a one size fits all scrubbing solution and usually a unique

system has to be designed to deal with the exact situation in question. For the boiler at equator

bottlers, considering the quality of the HFO used, the following will have to be dealt with in the

scrubber:

i. Oxides of nitrogen

ii. Sulphur dioxide and sulphur trioxide

iii. Carbon monoxide

iv. Particulate matter

Since there is no physical filter that will be able to separate these pollutants from the exhaust

gases (with the exception of particulate matter) the best solution will have to be a chemical one.

Most substances have a chemical that they can be reacted with to give them a much more

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physical state such as liquid or solid. In this state, these substance can be much more easily dealt

with. For some pollutants, there are substance that they react with that can change their chemical

composition to make them harmless.

Oxides of nitrogen

The best way of dealing with oxides of nitrogen is selective catalytic reduction (SCR). Selective

catalytic reduction is a means of converting nitrogen oxides with the aid of a catalyst into

diatomic nitrogen, N2 and water. A gaseous reducer, typically anhydrous ammonia, aqueous

ammonia or urea, is added to a stream of flue or exhaust gas and is absorbed onto a catalyst. SCR

is known to reduce the amount of NOx in exhaust by 70% to 95%. The chemical reactions that

occur to give these results are as follows:

i) To reduce nitrogen monoxide

4NO + 4NH3 + O2 → 4N2 + 6H2O

ii) To reduce nitrogen dioxide

2NO2 + 4NH3 + O2 → 3N2 + 6H2O

iii) To reduce both nitrogen monoxide and nitrogen dioxide

NO + NO2 + 2NH3 → 2N2 + 3H2O

There are several catalysts that can be used in the reduction process:

a) Base metal catalysts e.g. vanadium and tungsten: lack high thermal durability, but are less

expensive and operate very well at the temperature ranges most commonly seen in

industrial and utility boiler applications. They also have a high catalysing potential to

oxidize SO2 into SO3, which can be extremely damaging due to its acidic properties.

b) Zeolite catalysts have the potential to operate at substantially higher temperature than

base metal catalysts; they can withstand prolonged operation at temperatures of 900 K

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and transient conditions of up to 1120 K. Zeolites also have a lower potential for

potentially damaging SO2 oxidation. Iron- and copper-exchanged zeolite urea SCRs have

been developed with approximately equal performance to that of vanadium-urea SCRs if

the fraction of the NO2 is 20% to 50% of the total NOx. The two most common designs of

SCR catalyst geometry used today are honeycomb and plate. The honeycomb form

usually is an extruded ceramic applied homogeneously throughout the ceramic carrier or

coated on the substrate.

Sulphur dioxide and trioxide

The primary sulphur based pollutant produced is sulphur dioxide. Unlike the oxides of nitrogen,

sulphur dioxide cannot be reduced to give a simpler form. This is because sulphur has a much

higher affinity for oxygen than nitrogen and this means that a lot more energy will be required in

the reduction process or a stronger reducer will have to be used. All this will translate to higher

expenses for the company. High costs automatically reduce the viability of any solution.

The best solution is to control the conversion of sulphur dioxide and trioxide into sulphuric acid.

If this conversion can be controlled then the sulphuric acid produced can be better dealt with

instead of being allowed to fall back as acid rain.

Once the acid is produced, it can be neutralised using a suitable base. In most cases, the

conversion to acid and neutralisation occur concurrently as in the example below.

SO2 is an acid gas, and, therefore, the typical sorbent slurries or other materials used to remove

the SO2 from the flue gases are alkaline. The reaction taking place in wet scrubbing using a

CaCO3 (limestone) slurry produces CaSO3 (calcium sulfite) and can be expressed as:

CaCO3 (solid) + SO2 (gas) → CaSO3 (solid) + CO2 (gas)

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When wet scrubbing with a Ca (OH)2 (lime) slurry, the reaction also produces CaSO3 (calcium

sulfite) and can be expressed as:

Ca(OH)2 (solid) + SO2 (gas) → CaSO3 (solid) + H2O (liquid)

The CaSO3 (calcium sulfite) can further be oxidized to produce marketable CaSO4 · 2H2O

(gypsum). The production of gypsum can help to offset the costs of desulphurizing the flue gases

as the flue gas can be sold and put to other uses such as making quick dry walls. To promote

maximum gas-liquid surface area and residence time the best system to use is a spray tower. In a

spray tower the flue gases enter from below while the solution contain the scrubbing chemicals

fall from a shower above. A typical schematic for such a system is shown below.

Fig. 4: Scrubber schematic

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When it comes to choosing the scrubbing reagent, depending on the application, the two most

important are lime and sodium hydroxide (also known as caustic soda). Lime is typically used on

large coal- or oil-fired boilers as found in power plants, as it is very much less expensive than

caustic soda. Fortunately, calcium sulfite can be oxidized to produce by-product gypsum (CaSO4

· 2H2O) which is marketable for use in the building products industry.

Particulate matter

The easiest way of dealing with particulate matter is by using particulate matter filters. Most

particulate matter filters can be purchased whole as a single device and this can simply be added

onto the chimney. While it may seem that dealing with particulate matter is a fairly simple task,

it has wide implications when it comes to dealing with pollution.

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5. Analysis of Solutions

5.1 As far as switching the type of fuel used in the boiler is concerned:

a) Switching to a different fuel in the boiler will have a low initial cost but it is impossible

to ignore the high running costs that will come with this option. High running costs are

equivalent to a lifetime tax on the company. Running costs tend to increase with the size

of the company and the rising costs of fossil fuels cannot be ignored.

b) Most of the other proposed light fuels have a higher capacity to explode. Diesel and other

lighter oils if not well controlled during combustion can explode and natural gas is

capable of exploding even when not in use and this is quite dangerous.

c) While most of the other fuels have much less quantities of pollutants, the pollutants are

still present. This means that while they may be a better solution for now, in the future

the company may be forced to deal with the problem of pollution yet again.

5.2 When it comes to buying of a new boiler:

a) This option is quite expensive and it is technically an overhaul of the whole system.

b) A new boiler will also undoubtedly come with its own set of problems that will have to

be analysed a fresh over a period of time and solutions found for them.

c) Buying a new boiler also brings about the problem of what to do with old boiler. The

resale value of the boiler may be too low and keeping such a high capacity boiler simply

as a backup may not be good economic wise.

d) Simply buying a new boiler also passes the message that problems can simply be solved

using money. Buying the new boiler deprives the company’s engineering team of the

opportunity of coming up with a better solution to the company’s problems.

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5.3 Installing an exhaust gas scrubbing system:

5.3.1 Advantages

a) Since this is a system that has to be designed for the company in particular, it can give the

engineering team a challenge as they try and figure out how best to employ the scrubbing

system. This will be good for their overall experience.

b) The expertise that the engineering team will gain from adopting this idea can enable the

company to outsource this expertise to other areas and this can fetch a good amount of

money for the company. A good example is the Kipevu power plant that is currently

under construction. This power plant is intended to run on HFOs and undoubtedly,

expertise in keeping exhaust gases clean will be quite useful.

c) Using an exhaust gas scrubber also sets a good precedent for other smaller companies

that may not have the capacity to buy another boiler or to use a better but more expensive

fuel.

d) The production of gypsum from the exhaust gases helps to offset the costs that are

brought about by the system.

e) It is a great public relations mechanism as it clearly shows a company that is willing to go

the extra mile to protect the environment.

f) With the right set of options, the running costs will be quite low

5.3.2 Disadvantages

a) The initial costs might be relatively high.

b) Technical know-how will be needed to understand how to employ the system and how to

handle the chemicals required in the system.

c) The conversion of sulphur dioxide to sulphuric acid might damage certain parts of the

exhaust system if not contained properly.

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d) The system will take some time to design, construct and implement

Fig. 5: Final assembled flue gas scrubber

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Cost Analysis

Installation Costs

This means that the total costs for installing the flue gas desulpherizer will come to approximately

470,800 but may be much less than this. Apart from these costs, there are also costs that will be

incurred during the running of the desulpherizer.

Running Costs

Item Quantity Cost per item Total (Kshs)

Energy - - 2000

Water - - 1000

Personnel 2 12000 24000

Maintenance - - 2000

29,000

The total cost of reducing the pollution that the plant causes to a significant level comes down to only

29000 shillings. There are also other hidden benefits such as the provision of employment which in itself

has more benefits than can be seen.

Item Quantity Cost per item Total cost (Kshs)

Circulation pumps 3 60000 180,000

Water pipes (4m) 9 1200 10,800

Gas distribution tray 2 5000 10000

Slurry agitators 5 2000 10000

Sheet metal (10m2) 7 7500 52500

Miscellaneous Materials - - 20000

Skilled Personnel 2 50000 100000

Unskilled Personnel 5 15000 75000

Wiring - - 5000

Energy costs (Welding, riveting e.t.c)

7500

470,800

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5.4 CONCLUSION

1. When all is considered, the best solution is to make use of an exhaust gas scrubber. Its

advantages stretch beyond the limits of the company and setting a good precedent for

other companies will be vital to the preservation of the environment in the lake city. This

solution is also a bargain between the very high initial cost of buying a new boiler and the

high running costs of using a different type of fuel.

2. This solution will also enable the company to come up with an expert team. The ability to

outsource experienced labour is proving to be a major source of income for other

companies whose primary focus is something else.

3. This solution is not only applicable where HFOs are used but also where other fossil fuels

such as diesel are in use.

5.5 RECOMMENDATIONS

1. Equator bottlers should take the initiative to construct an exhaust gas scrubbing

system for their boiler.

2. The city of Kisumu should set down laws that will restrict the use of HFOs or

encourage the use of exhaust gas scrubbers if it wishes to protect its environment

from pollution.

3. Equator bottlers and other companies should ensure that environmental preservation

becomes a culture, a habit and a necessity in industry and not just a public relations

stunt.

4. Use the engineering team in equator bottlers and bring in one or two skilled

personnel on a permanent basis to employ this solution. This will help the company

to build an expert team.

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5.6 References

1. Office of Air and Radiation United States Environmental Protection Agency(1997):

Nitrogen Oxides: Impacts on Public Health and the Environment

2. WBK & Associates Inc(2003): Sulphur Dioxide:Environmental Effects, Fate and

Behaviour

3. Birhanu Genet(2008): Health and Environmental benefits of low Sulphur Fuels

4. Anlagenbau GmbH & Co. KG(2012):Flue Gas Purification for Heavy Fuel Oil (HFO)

Fired Engines

5. CONCAWE’s Petroleum Products and Health Management Groups(1998): Heavy Fuel

Oils

6. Lee Bell BA MA(2009): The Heavy Oil Power Deal: A Dark Cloud over East Timor’s

Bright Future

7. IS:6533 Indian Standard(2001): DESIGN AND CONSTRUCTION OF STEEL CHIMNEY

— CODE OF PRACTICE