Final report 2017

FINAL INTERNSHIP REPORT ON METEHARA SUGAR FACTORY

Declaration

We hereby declare that the report work entitled "final internship report" submitted to Addis

Ababa University Institute of technology school of chemical and Bioengineering is a record of

original work done by us under the supervisor and guidance of our esteemed mentor Ato

Habtamu Asmare and Ato Zenabu Tasew. And this report/project work is submitted in the partial

fulfillment of the requirements for internship session of 2016/2017 held for 4th year students of

Addis Ababa University Institute of technology school of chemical and bioengineering. The

results embodied in this report have not been submitted to any other University or Institution for

the award of any type of work.

Approved by:

Name of Mentor: ZINABU TASEW and HABTAMU ASMER

Signature: _________________

BY ABNET MENGESHA DUBE, 2017 , ADDIS ABABA, ETHIOPIA


Acknowledgment

We wish to acknowledge and thank all our supporters in our internship program. In particular,

we would like to express our deepest gratitude and appreciation toAto Zenabu Tasew and

AtoHabtamuAsmare, our advisor and internship program coordinator for his limitless support

and giving advice during our inter period in Metehara sugar factor.

We are very grateful to YenesewTakele for his supervision, giving necessary materials and

support in Metehara sugar factory during our internship program.

We extend our gratitude to all Metehara sugar factory workers who were willing to share their

knowledge and skills.

In closing, we are deeply grateful to Metehara people for their hospitality and kindness during

our stay at Metehara.



Executive Summary

This section of the report is written with the aim of providing general information about the

internship program which helped us to gain practical know how on our field of study.

The hosting company of our internship program is called metehara sugar factory which is located

200 km south east of Addis Ababa it was established in 1965.The main purpose and mission of

the organization is to produce sugar of standard quality with a least possible cost and satisfy the

needs of its customers. In addition to the production it utilizes all resources at disposal without

creating any kind of pollution to the environment.

Main activities of the factory are

Grow sugar cane and process it to produce sugar. Distribute and sell sugar. Produce ethanol by processing the molasses coming out as a byproduct from sugar

production to mix it with petroleum for cars. And the rest byproduct is used for bio compost (fertilizer) production.

During our internship we were able to work on the whole process of sugar production starting

from the cane handling up to the last sugar packing. In addition to this we were able to see the

production of ethanol from the sugar byproduct /molasses/. We started our work from the cane

handling and preparation section where the harvested cane is weighed and prepared for

extraction process by reducing its size. Then we proceeded to the next station which is the juice

extraction section. Here we worked on the mechanisms that the juice inside the cane is extracted.

Next to this we worked on the milk of lime preparation station, in this station milk of lime is

prepared from raw calcium oxide to be used in different processes. Then after lime station we

proceeded to so2 gas generating station where so2 is produced to be used in other processes.

Next what we worked on was the juice clarification station. Here the extracted juice coming from

the mills will be clarified. After clarification the proceeding plant was the evaporation plant

where the clarified juice from the clarifier is evaporated to brix it up. Then we passed to

crystallizing plant where crystals of sugars are formed. After the crystals are formed the next

station we passed on was the centrifugal and drying process where the formed sugar crystals are

separated from the massecuite by a centrifugal machine. Then the last unit operation we



observed was the drying and packing station. Finally in addition to the sugar producing plant we

had the chance to work on the ethanol production plant.

Abbreviation and Acronym

B: bagasse

Br: degree brix

C: cane

CJ: clear juice

E1: water evaporated at evaporation unit

E2: water evaporated at vacuum plant unit

ELPA: Ethiopian electric power authority

FC: filter cake

HVA: Hangler Vonder Amsterdam

ICUMSA:international commission for uniform method of sugar analysis

Imb: imbibition

Imp: impurities

MIS: management information system

MJ: mixed juice

Mo: molasses

MSF: metehara sugar factory

Pol: polarization

RS: reducing sugar

S: sugar

W: water



Table of Contents

Acknowledgment ii

Executive Summary iii

Abbreviation and Acronym iv

Table of Contents v

List of tables viii

List of figures viii

Chapter One 1

1 Background of the Hosting Company 1

1.1History and Location 1

1.2 Vision 2

1.3Mission 2

1.4 Future plan 2

1.5 The main Purposes of the Enterprise are to 2

1.5 Main Products and Services 3

1.7. Main Customers or the End Users of Its Products and Services 3

1.8. Organizational Structure 3

Chapter Two 5

2 Overall Internship Experience 5

2.1 Joining of the Company 5

2.2 Section of the Company We Have Been Work 5

2.2.1 Flow in the Section 6

2.3 Work Piece or Tasks We Have Been Executing 8



2.3.1The Overall Sugar Production Process 8

2.3.2Steam and Power Generation Plant 16

2.3.3Ethanol and Production Process Related Product 17

2.3.4The Overall Laboratory Analysis for the Above Three Processes 17

2.3.5 Identified problems 18

2.4 Procedure We Have Been Used When We Perform Work Task 19

2.4.1 Cane Weighing 20

2.4.2 Cane Unloading and Preparation 20

2.4.3 Juice Milling and Screening 20

2.4.4 Juice Diffusion and Screening 20

2.4.5 So2 Gas and Milk of Lime Preparation 20

2.4.6 Clarification and Evaporation 21

2.4.7 Crystallization and Centrifugation 21

2.4.8 Laboratory 21

2.4. 9 Material and Energy Balance 22

2.4.10 Boiler Plant 22

2.4.11 Ethanol Plant 22

2.5 Our Performance during Our Internship 24

2.5.1 Challenges We Have Faced 24

2.5.2 Measures We Took To Overcome the Challenges 24

Chapter Three 25

3 Overall Benefits Gained From the Internship 25

3.1 Learned Practical Skills during Internship 25

3.2 Up Grading Theoretical Knowledge 27



3.3 Upgrading Interpersonal Communication Skill 27

3.4 Improving Team Playing Skill 28

3.5 Improving Leadership Skill 29

3.6 knowledge Gained In terms of Work Ethics and Related Issues 29

3.7 Entrepreneurship Skills 30

Chapter Four 32

4.1 Conclusion 32

4.2 Recommendation 33

4.2.1 Recommendation to the Company 33

4.2.2 Safety work in the Factory 34

4.4.3 Accident Administration 35

4.4.4 Recommendation to the School 35

Appendix 36

References 44



List of tables

Table Title Page No

1 Some difference between two tandems in metehara sugar factory 10

2 parameters controlled in extraction unit 11

3 Hydraulic pressure (bar) 12

4 Pre-charging nitrogen pressure (bar) 12

5 mill rotor’s speed (rpm) 12

6 Mill turbine’s rotational speed (rpm) 12

7 clarification and filtration processes parameters and specifications 14

8 Some standards for material balance 39

9 Calculation for extraction, clarification and evaporation unit 41

List of figures

Table Title Page No

1 Organizational flow chart of Metehara Sugar Factor 4

2 Metehara sugar factory work flow diagram. 7

3 General process flow diagram of sugar production process 23



ChapterOne

1.Background of the Hosting Company

1.1History and Location

Mathura Sugar Factory is located some 185km South East of the capital city Addis Ababa, on the

Addis Dire Dawa-Djibouti road within the upper Awash Valley. It is situated at 8 53’N and 39

52’E. In the immediate vicinity of the Enterprise one can find tourist attractions such as Awash

National Park, Fentale Mountain and Lake Beseka.

The establishment date of Metehara Sugar Factory goes as far back as 1965, the time when the

Dutch company, named as HanglerVondr Amsterdam (H.V.A) had surveyed the area for future

sisal development. The increasing demand for sugar in Ethiopia and the suitability of the land

and climate for sugar cane cultivation urged H.V.A to extend the sugar industry to Metehara

Plains.

As a result in July 1965 an agreement was signed between the Ethiopian Government and the

Dutch company (H.V.A) under which the company acquired a concession of 11,000 hectares of

land, Subsequent to the signing of the agreement, sugar cane cultivation was started in 1966.

The Factory started producing plantation white sugar on the 9 of November 1969 with an initial

crushing capacity of 1700 tons of cane per day (TCD). Since then, the factory had undergone

successive phases of expansions. The first expansion was made in 1973 to raise the crushing

capacity of the factory to 2450 TCD. The Enterprise was nationalized in 1975 and organized

under the Ethiopian Sugar Corporation. Then the second and the third expansion took place in

1976 and in 1981, which raised crushing capacity to 3000 and 5000 TCD respectively. The

Ethiopian Sugar Corporation was legally dissolved in 1992/93. Following the dissolution of the

Ethiopian Sugar Corporation, Metahara Sugar Factory was established as an autonomous public

enterprise in 1992. The company has 3700 permanent and 6300 seasonal employees. About 65%

of the annual sales volume is undertaken in the domestic market while the remaining 35% is

exported to neighboring countries. The enterprise possesses one sugar mill with a crushing

capacity of 5,000 tons of cane per day (TDC) and sugar cane plantation of 10,000 hectares.

Annually, about 1,027,500 tons of cane is harvested and supplied to the factory for crushing.



The Enterprise currently has a total concession area of 14733 hectares out of which about

10,300 hectares is covered with cane plantation.

1.2 Vision

Their vision to the future is to become one of competitive and leading company in Africa.

1.3Mission

The mission of the organizations is:

to Produce sugar and ethanol of standard quality at a least possible cost and satisfy its customers;

utilizes all resources at disposal

To provide best service to the society at large

remain competitive and profitable,

To be environmentally friendly in its process as well as to provide affordable living standard to its employees.

1.4 Future plan

Amongst its short-term and long-term projects, MSF plans to export to Europe, the Middle East

and Gulf countries, and to diversify its products and to expand its land for cane plantation.

1.5 The main Purposes of the Enterprise are to

Grow sugar cane and other sugar yielding plants

Process and produce sugar and sugar by products.

Distribute and sell sugar and sugar related products within the country and abroad.

Study, plan and implement various sugar development programs.

Carry on scientific, industrial and agricultural research and surveys to enhance its programs.

Possess and develop agricultural lands in the country whenever it is deemed appropriate to fulfill its purposes.

Engage in other activities that enables the attainment of its purposes



1.5 Main Products and Services

1. Sugar

Sugar is the main product supplied mostly to a domestic market. The annual sales volume stands

at about 120,000 tons

2. Ethanol

The major part of molasses produced is used for producing ethanol around 1.2 million liters of

ethanol is produced annually.

3. Fruit

Fruit such as orange, lemon, mango and mandarin are subsidiary products of the factory

1.7. Main Customers or the End Users of Its Products and Services

The domestic uses most of the sugar production and different alcohol factories use the product of

ethanol.

1.8. OrganizationalStructure

The Enterprise operates as an independent economic entity with relative management autonomy.

The enterprise has an automated Management Information System (MIS) that enables generation

of reliable and simplified information for decision making.

The Enterprise has also built Quality Management System (ISO 9001:2000) into its processes

that will ensure the capability of the enterprise to deliver quality products and services to its

customers.

The Enterprise has adapted a team management style and the structure comprises four broad

sectors, namely, Agricultural Operations, Factory and Logistics, Finance and Human Resource

as shown in the chart below. Support giving and advisory services are also shown in the chart.





Chapter Two

2.Overall Internship Experience

2.1 Joining of the Company

Since we finished 3rd yearclass we are provided the application letter from UIL office for the

intern and all of us started searching for hosting company that satisfy our interest as we are

chemical engineering student. We interested with the company that has many unity operations to

associate our theoretical knowledge with the real world working skill and experience. We

applied for intern to many company in Addis Ababa like Nifas silk paint factory, Dil paint

factory, national alcohol factory, Moha soft drink factory, coca cola, ECIA, etc. most of these

company reject our application since the place they have is occupied by other university

students. And some of them are accept us, but we were not satisfied by them because they have

small number of unit operations. Then we intern friends, motivated and decide to go to Metehara

sugar factory since it has so many unit operations and different plant like sugar production plant,

steam and power generation plant, ethanol production plant, bio composting plant and water

treatment plant. In the next day we talked to AtoAbiy UIL office head about our decision and we

asked him about general condition that exists in Metahar sugar factory and its area. He was very

excited by our decision and encourages us to go there. After two days on November 01/2016 we

prepared our self to go Metehara. The journey was boring and tedious because the weather is so

hot comparing to Addis Ababa. When we reached there, we were very amazed because the

compound is very large and it takes a time to reach HR office starting from the get. The HR

personnel and all company workers were welcomed us very cheerfully with deepest love. And

they prepare for us resting place and give us the necessary information that we needed.

2.2 Section of the Company We Have Been Work

Metehara sugar factory is the oldest and largest company in Ethiopia. Thus it has many working

section and subsections. These sections are broadly divided into six major parts these are:

Cane cultivation and related work section

Sugar production section

Steam and power generation section



Sugar, ethanol and boiler water laboratory

Ethanol and related work section and

The overall administrative and other related work section

We as intern of chemical engineering have been work on three major section. These sections are:

Sugar production section Steam and power generation section Sugar, ethanol and boiler water laboratory and Ethanol and related work section

We have been working in these sections per schedule we were given. Here in each section there

are different subsections. In sugar production process we were worked on cane handling and

preparation unit, juice extraction unit, clarification unit, So2 and milk of lime preparation unit,

evaporation, vacuum plant, centrifugation and drying and sugar finishing units. In steam and

power generation plant worked for little period of time but here we mainly focused on the

problems part. This unit is essential unit but has several problems. In ethanol production unit we

have worked on water treatment unit, fermentation unit, distillation unit, evaporation and bio

composting unit. Finally we have worked on laboratory section, to analysis different parameters

as they are on their standard condition and to determine different quantities amount and their

quality. The other section that we have been working is problems identification and giving some

idea how they are solved.

2.2.1 Flow in the Section

Here in metehara sugar factory all activities are done hierarchically, each members of the

hierarchy has its own tasks and responsibility. Since the company follow the cozen principle the

rule and the position given is applicable.

The working flow of metehara sugar factory sugar, ethanol production and steam/power

generation has many advantages to work closely and efficiently and to solve problems between

them. The factory is working according to the flow. The factory flowis look like the following:



Figure 2: Metehara sugar factory work flow diagram.

Team leaders:the main responsibility of team leaders is to lead the whole team by facilitating

the necessary conditions for work, and communicate with the administration, given orientation

for new employees, trainees, interns etc.

Production team:these are different experts which has different tasks. Their main responsibility

is to solve problem that arise in factory and finding new way of improving the factory

performance.


team leaders

production team

coordinators team

supervisors team

forman team

operators team

labors


Coordinators:these are not many in each part there is one coordinator. The main responsibility

is to make bridge between team leaders and supervisors. They are responsible to solve problems

that are beyond the ability of supervisors and closely follow the work process that take place.

Supervisor’s team: these team work most of the time in factory in each part of the factory like

front factory, middle factory and back factory. They are more close to Forman and other lower

personnel. The immediate person that responsible to solve work problem is supervisor.

Forman’s team: these groups are worked with supervisors. They are supervisors assistants and

worked with operators closely. If there is problem they solved if it is minor.

Operators: they are responsible to operate in limited unit operation for the given working time;

Labors: they are worked at different part work that not required technical knowledge.

NB.All the above personnel arranged/placed to their respective position according to their skill,

experience, academic knowledge.

2.3 Work Piece or Tasks We Have Been Executing

As we tried to explain above we have been working at different parts of the company. As

chemical engineering student we tried to acquire practical skills, knowledge and experience that

chemical engineers acquired. Generally we have worked at five different section as we

mentioned above. These are:

The overall sugar production process section

Steam and power generation process section

Ethanol and related product production process section

The overall laboratory analysis for the above three processes section

Problems identification and giving some solving ideas

2.3.1The Overall Sugar Production Process

In our four month internship period we experienced whit the sugar production process by the

help of different persons like Forman, operators, team leaders, coordinators and etc. Here there

are different tasks that we worked on. This task includes:



Cane Handling and Preparation

Cane handling and preparation is the first unit operation in sugar producing process in which

cane is prepared for extraction process. The task that take place here is includes, cane weighing,

cane unloading and leveling, size reduction, transportation, ferric material separation. Metehara

sugar factory has two tandems that has different capacity and working conditions. The main

objective/ purpose of this unit operation is to prepare cane for extraction plant by reducing the

size and exposing cells to be extract. The whole process derived by steam and electrical motor.

We have worked here for about a week with all types of personnel in both tandem. The two

tandems has some difference that make them different in production capacity.This difference is

shown in the following table clearly.



Table1: some difference between two tandems in metehara sugar factory.

Specification/parameters Tandem A (old) Tandem B (new)

Capacity 15-20 cart cane/hr. 25-30 cart can/hr.

One cane table capacity 2tonn 2tonn

First cutter power 285KW 290KW

First cutter speed 585rpm 591rpm

Second cutter power 30KW 30KW

Second cutter speed 460rpm 585rpm

Fiberizer speed 600rpm

Cane Juice Extraction Process

Cane juice extraction is the process of separating juice from bagasse. We have worked here for

about two weeks in both tandems with all types of personnel. In metehara sugar factory there are

two tandems that use different methods to extract juice. The first use five mill that arranged in

series. And the second uses three mill and one bagasse diffuser, diffuser extract juice by

diffusion and leaching. But mills extract juice by using hydraulic pressure. In first tandem juice

from the first two mill screened and sent to process. The remaining mill’s juice is used as

imbibition. In the second tandem juice from first mill and diffuser sent to process and the

remaining mill’s juice used as press water. The bagasse that sent to last mill takes hot/cold water

as imbibition. And the final bagasse sent to boiler plant as fuel. Here there are some parameters

and specifications that controlled in extraction unit. These are listed in the following tables. The

table also contain the reason of the parameters are controlled in the range specified.



Table 2: parameters controlled in extraction unit

Parameters/specifications Amount/result Reasons

Imbibition water flow

rate

35-40m3/hr. Deviation from this range is uneconomical

Final bagasse moisture

content

50% Taking the moisture content below this is impossible

If it is above it affect energy production process

Juice loss with final

bagasse <

2.5% Making less than this take more cost Making above is loss of sugar

1st mill extraction

capacity

60-70% Deviation in both direction is uneconomical

10 juice purity and brix >84% and

>190Br

It mostly depend the mill capacity and cane

sucrose content

20 juice purity and brix 82-83% and

10-110Br

It mostly depend the mill capacity and cane

sucrose content

MJ brix, sucrose content

and purity

16-170Br,13-

140Z

and >84%

The result of 10 and 20 juice. When their

quality fluctuate the MJ also fluctuate

Diffuser temperature 70-750C Below 70 lead to inefficient juice extraction.

Above 75 lead to additional steam cost

Retention time of

bagasse in diffuser

45min To extract more juice the bagasse need more

time but the very longer time is undesired

since no more juice extracted in the added

time duration.



Table 3: Hydraulic pressure (bar)

Mill 1st 2nd 3rd 4th 5th

Turbine side TA

190-200 150-160 150-160

Opposite side TA

190-200 150-160 150-160

Turbine side TB

120-140 120-140 140-160 150-170 160-180

Opposite side TB

120-150 130-150 150-170 160-180 170-190

Reason of pressure decrement is extraction inefficient as the bagasse goes from the first to the last mill since the liquid content is decreased.

Table 4: Pre-charging nitrogen pressure (bar)


Pressure TA 16o 135 135

Pressure TB 115 115 135 145 150

Table 5: Mill rotor’s speed (rpm)


Speed TA 4-6 4-6 4-6

Speed TB 4-6 4-6 4-6 4-6 4-6

Table 6: Mill turbine’s rotational speed (rpm)


Speed TA 5000-6000 5000-6000 5000-6500

Speed TB 5000-7500 5000-6500 5000-6500 5000-6500 5000-6000



Speed is increased from the first to the last mill to increase attachment between bagasse and rollers. To increase extraction efficiency.

So2 Gas and Milk of Lime Preparation Process

These are two independent units which take different input and give different product that used

in the clarification process. We have worked here for about a week. Milk of lime is produced

from quick lime and water by exothermic reaction as follow:

And then the grit and clear milk of lime is separated through different types of screens. And then

the clear milk of lime sent to pre-liming station. It has concentration of 8-100Be. So2 gas is also

produced by exothermic reaction from sulphur and air/oxygen as the following reaction

S+ O2 ===> SO2

The prepared gas sent to juice and syrup sulphitation station. The temperature of process gas

must below 600C. thus to get this temperature the 3600C gas passed through different cooling

system like primary cooling, secondary cooling and cooling scrubber.

Mixed Juice Clarification and Muddy Juice Filtration Process

This the collection of unit operations like weighing MJ, sulphitation, liming, heating,

flocculation, flashing, clarification and filtration. Here we have worked for about two weeks and

we tried to experience something about the process that takes place there. The purpose of

clarification and filtration unit is generally to separate juice from its different impurities and to

heat the CJ to its liquid saturation point to reduce evaporation load. The process flowed like this,

MJ from extraction plant is weighed and it passes through first heating system to heat the juice to

70-75 0C before it entered to liming and sulphitation system to reduce the solubility of calcium

sulphate at low temperature this is to facilitate precipitation process and to deactivate

microorganisms. Then the juice limed to keep the PH between 7.2-7.4 and sulphited to neutralize

the excess milk of lime, bleach the color and used as disinfectant agent. Then the juice is passed

through second heating system to heat the juice to 100-102 0C to flash out incondensable gases

before entered to the Dorr clarifier, this is to facilitate the settling process. Then sent to Dorr

clarifier for settling purpose, here the juice is mixed with flocculants/in metehara case sapara to

settle down small particles and colloidal. The mud is separated here from the juice. The clear



juice sent to third heating system to heat it to 110-115 0C to reduce evaporation load by reaching

the juice to its liquid saturation point. The muddy juice sent to OC filter to further separation of

juice from the mud. Then mud sent to bio-composting and the filtrate returned to servo balance.

So many reactions are take place from these the following is the most important:

Ca (OH)2 +So2 CaSo3 +H2O

There are some specifications and parameters that controlled here are listed in the following

table

Table 7: clarification and filtration processes parameters and specifications

Parameter Value specification Value

Brix of MJ from mills 15-17 0Br Old Dorr volume 298m2

Phosphoric acid content of weighed MJ

300-350 ppm New Dorr volume 332m2

1st heating temperature 70-75 0C

PH of limed juice 8.6-9.0

PH sulphited MJ 7.0-7.2

2nd heating temperature 100-1020C

Sucrose content of muddy juice 17%

Lime to mud mixer PH 8.0-8.5

Muddy juice temperature 700C

Temperature of hot water to OC filter

600C

3rd heating temperature 110-1150C

Retention time in liming tank 7-10 se

Retention time in sulphitation tank

10-15 se

Pol% of filter cake <2.5%

Moisture of filter cake% 70-75%

Brix of CJ to evaporation 15-17 0

Evaporation



This is the unit operation where water and CJ is separated to make syrup/concentrated juice brix

of 60-65 0Br. Here we have worked for about three weeks with different personnel and we

experienced with the process controlling system, operation system, and steam economy and so

on. Metehara sugar factory uses two type quadruple effect evaporators Robert and kestner type

evaporators. Their differences are in Robert type one vessel comprises vapor body and steam

chest together and the number of vessels is 5. But in kestner type vapor body and steam chest are

different bodies and the number of vessels is six. The process is, first juice from clarification

station entered to pre-evaporators calanderia tube exhausted steam from mill turbine and power

generation entered to steam chest and boils the juice. The concentrated juice sent to the next

effect and the vapor bleed sent to vacuum plant, to the next effect, and preheaters. Then vapor

bleeds from the effects sent to boil the juice further and the last concentrated juice sent to syrup

sulphitation station. And the last effect vapor bleed sent to condenser to make vacuum with the

aid of cold water jet. Condensates sent to flash tank to flash out vapor it contain and then it sent

to boiler plant, the flashed vapor returned to steam chest. The parameters that controlled in this

unit are:

Juice in flow rate

Syrup out flow rate

Vessels level

Steam temperature and pressure

Vacuum of the vessels and

Brix of the syrup (60-65 0C)

Syrup Clarification and Vacuum Plant Operation

This is the unit where syrup is clarified by sulphitation and crystallization process is take place.

We have worked here for about two weeks and we grasped some practical skill and we

developed our theoretical knowledge. In MSF there are 10 vacuum pans that all worked under

vacuum to make different grade massecuite. Here there are three types of masscults. These are A,

C and D massecuite. The crystallization process is take place at three different places. These

are,vacuum pan, strike storage tank and cooling crystallizer. The crystallization process is



favorable at metastable zone, super-saturation state where the existing crystals are growth and no

new crystal is formed to avoid false grain formation. The main aim of the unit is to separate the

crystal from mother liquor. In metehara only A massecuite is processed for marketing purpose

and the remaining low grade massecuite returned to the plant as a seed and input material. The

following are parameters that controlled in this unit.

Quality:-uniform grain size Vacuum pressure (60-75)cmhg Input syrup brix(60-65)0bx Vapor bleed 0.6 bar Final sugar grain size(0.66-1)mm Final sugar purity(92-94)0bx Chest temperature(65-70) Injection water 0.5 bar Final molasses<36 0bx and Pol<2.50Z

Centrifugation, Drying and Sugar Finishing

The main purpose of centrifugation is to separate sugar from molasses and that of drying is to

separate some amount of moistures from the sugar to avoid sugar destruction. We have worked

here for about a week. The process is massecuite from vacuum plant introduced to pug mill and

rotates by high speed to create centrifugal force and here molasses and sugar is separated. Then

sugar is clarified by different means and then sends to dryer. In dryer hot air is delivered to

exchange heat and the dried sugar sent to cooler and then to finishing unit. Here in finishing

unit sugar is screened, bagged and stored.

2.3.2Steam andPower Generation Plant

Here we have worked for few days since the working environment is very hard and dangerous.

Even if we have work for few days we experienced some practical and theoretical skill. The

main purpose of the plant is to produce power for the whole plant. The main raw materials used

are bagasse as fuel, water, oil. And the main products are steam, electricity, smock and ash. The

process is, bagasse from extraction tandems burnet and generate fuel gas and water is boiled to

its super-saturation point to produce steam. The parameters controlled here is boiler water quality

and steam quality. Then the produced steam sent to different parts of the sugar plant as source of

energy and to power plant to produce electricity. There are several apparatus that used here for

different purpose, generally to increase boiler efficiency. These apparatus are:



1) Furnace: used to combust bagasse by hot air.2) Economizer: used to heat feed water before it entered to the drum by recovering the

lost fuel gas.3) Steam drum: the place where steam is generated and stored. There are two drums

lower and upper.4) Super heater: used to heat the steam further to its super saturation point to increase

pressure and temperature of the steam or to increase steam quality. This is done by recovering the latent heat of lost flue gas.

5) Air heater: used to heat cola air to increase its temperature by recovering energy from lost flue gas.

6) Fans: used to pressurized the input and output gas.

2.3.3Ethanol and Production Process Related Product

Here we have worked for about two week and we have grasped some practical skill and

developed our theoretical knowledge. Here we have worked at five different sections, water

treatment, fermentation, distillation, evaporation and bio-composting sections. The general

process is, first culture media is prepared in lab and then fermentation process is started. After

we get the good amount of alcohol the wash is sent to distillation column. Here the alcohol and

vinasse is separated. And vinasse sent to evaporators to reduce the water amount before it sent to

bio-composting plant. The alcohol is further purified to produce technical alcohols, RS and

ethanol. Some parameters are controlled here.

Final alcohol strength Final vinasse brix In each column temperature and pressure Microorganism size and shape in culture media. Retention time at different place.

2.3.4The Overall Laboratory Analysis for the Above Three Processes

Here we have worked for about ten days and we have grasped some practical skills. The main

purpose of the lab analysis is to control failure and improving systems capacity by

determine/measuring different parameters. Here generally three types of analysis is take place.

These are:

A,Sugar Analysis



Here there are several analyses that analyzed for different purposes. These are:

Cane analysis (to analyzed cane contents like fiber, water, sucrose, reducing sugar, and impurities)

Bagasse analysis (to analyzed, moisture content pol loss with bagasse)

Juice analysis (to know its content amount)

Filter cake analysis (to know pol loss with filter cake) Molasses (to know purity, and its content amount) Syrup analysis(to know the brix/concentration) Massecuite analysis (to compare it with standard )

B, Boiler Water Analysis

Here also several analysis to protect the boiler safe.

Hardness and phosphate analysis

Conductivity analysis

Partial and total alkalinity

C, Ethanol Analysis

Here also several analysis for different purpose.

Microorganisms shape and size in culture media Alcohol strength and purity Vinasse brix Process water

2.3.5 Identified problems

This section is the most important of ours because it challenges us to think to identify the

problem and to generate solution idea. We have observed lots of problems from the initial point

to the last one. Problems here have different dimension so we focused only on the problems that

related with our field of study. In addition, we have tried to identify problems in each section.

1. Sugar Production Process Problems

Here there are several problems. These are:

Poor cane preparation and low preparation index



Low extraction capacity, sucrose loss with bagasse, filter cake and final molasses, poor juice storage Malfunction of diffuser Steam and juice leakage Scale formation in pipe and around pipes Low quality sugar is marketed

2. BoilerPlant Problems

Here there are few problems that have large and essential effect on the whole plant. These are:

There is no boiler treatment plant Steam loss Energy loss through smoke

3. Ethanol Plant Problems

Here also there are problems. These are

Shortage of power Equipment worn-out

4. Laboratory Problems

Here there are lots of problems. These are

Incapable personnel are there. Poor accuracy Carelessness and Improper equipment

The solution ideas are listed in the recommendation section of this paper.

2.4 Procedure We Have Been Used When We Perform Work Task

As we mentioned we have been worked at different section of the company. Even if each section

has its own detail procedure we mainly focused on the major procedure that we have been used.

Tasks that we have done aredetailed with process, apparatus used, specification and parameters

and flow diagrams and pipe line drawings and we submit report for the company in each section.

Generally we follow the schedule we have given.



2.4.1 Cane Weighing

Cane weighing is the first step of cane sugar production. We have weighed cane here for five

continuous days to know the average cane input to the system. The aim of the unit is to know

how much amount of cane is processed per day, remained in the yard and to the payment

purpose. Here we follow some procedures.

Cane variety, field number and cart number is recorded Empty cart weight is recorded Weight of cart and cane is weighed and recorded The difference is recorded.

2.4.2 Cane Unloading and Preparation

Cane is unloaded on the cane table and leveled and transported to the cane cutters. The size of

the input cane stalk is reduce in the cutter. Then ferric materials are separated. The main object

of the unit is to prepare proper fibered cane to the extraction unit.

2.4.3 Juice Milling and Screening

Here prepared cane is passed through a series of mills and squeezed between the rollers by

applying hydraulic pressure. The extracted juice screened through vibrational screen and sent to

the process. The main object of the unit is to separate juice from its fiber.

2.4.4 Juice Diffusion and Screening

Here the bagasse from the first mill forced to the diffuser by scalding juice. And leaching and

diffusion process take place. The main object is to increase the extraction efficiency and to

reduce sucrose lost.

2.4.5 So2 Gas and Milk of Lime Preparation

We prepare so2 gas and milk of lime for clarification purpose. In the process of so2 gas

generation we follow some procedures.

Atmospheric air is dried and compressed Solid sulphur is melted The reaction is take place between dried air and molten sulphur The generated so2 gas is cooled and sent to clarification plant

The procedure we followed to prepare milk of lime



Quick lime and hot water reacted in lime slacker. Classified into milk of lime and grit Clarified milk of lime and sent to process.

2.4.6 Clarification and Evaporation

This is the most important and sensitive unit of all. The main object of the unit is to separate

juice from its impurities and to maintain the PH of the system. And that of evaporation is to

separate water from juice. We followed some procedures here during our performance.

Juice is heated Limed and sulphited Flashed Flocculation Clarified and sent to the process Filtered and sent to the process Juice and steam is sent to the stem chest Concentrated juice sent to after some retention time Vapor bleeds sent to vacuum, condenser and pre-heater Condensate to boiler plant

2.4.7 Crystallization and Centrifugation

The main object of the crystallizer is to separate crystal from mother liquor and that of

centrifugation is to separate sugar from molasses. We have followed some procedure when we

work on these units.

Syrup is sent to pans Steam/ vapor bleed is sent here Vacuum is created Massecuite is sent to centrifugal machine Then the massecuite centrifuge and sugar sent to dryer and then to market.

2.4.8 Laboratory

Here in lab there are several analysis and we follow the respective procedure for each analysis.

The main purpose is, to differentiate the problems and to take an action at each plant.



2.4. 9 Material and Energy Balance

We done material and energy balance to solve our project problems. We followed some

procedures to calculate the factory material and energy balance. The result of our calculation is

attached at the appendix. The procedures that we followed are:

We take standards and basic, and also assumptions Calculate the general balance and Calculate for the components Use the result to solve our problems And recommend on the result

2.4.10 Boiler Plant

We have worked here for very few days. The main object is to produce energy. We followed

some procedures here.

Bagasse is feed to furnace Steam is further heated Air is heated Steam is distributed to different sections Smock is released through chimney

2.4.11 Ethanol Plant

In ethanol plant there are five sections and each section has their own procedures that take place.

Thus we focused only on the main procedures that we followed.

Water is treat before entered the fermentation unit as process water. Culture media is prepared Fermentation is take place The fermented mixture is clarified and the wash sent to distillation for the separation process The alcohol is separated from the vinase and then it purified further. Water is separated from the vinasse and then vinasse sent to composting plant. Compost is prepared from vinasse and filter cake.

We summarized our tasks at sugar production process section by the following general process flow diagram.



Figure3: general process flow diagram of sugar production process


cane handling and preparation

juice extraction

so2 gas and milk of lime preparation

juice clarification

juice evaporation

crystallization

centrifugation

drying and cooling

sugar finishing


2.5 Our Performance during Our Internship

During our internship class we were able to integrate with the workers within a short period of

time

And get involved in different works to gain more knowledge about the working environment to

improve ourselves. We were able to perform all our duties nicely and get knowledge from the

practical world and relate it with the theory we learned in class and we upgraded ourselves in to

another level of skill, ethics, knowledge and leadership using this internship class. Since the

factory has already given us a schedule we have done all our works based on that and after the

completion of every work we had submitted a report to the factory .In addition to that we were

able to attend training session that was given by the factory which helped us to gain more

knowledge. Generally during the last four months we have performed very well.

2.5.1 Challenges We Have Faced

Since internship is a whole new experience and the area is a bit far and remote we have faced

different kinds of problems in the last four months. Such as:

The Weather condition was very hot and it was very difficult to adapt to the environment. Since the factory was so old and don’t have well equipped air conditioning system it was

so hot and difficult to work. The stairs and bridges were very old and worn out, it makes our works so dangerous. Since the factory was so old and because of some maintenance problems we weren’t able

to see some machineries. Lack of safety facilities.

2.5.2 Measures We Took To Overcome the Challenges

From the mentioned challenges above we were able to come up with solutions to some of the

problems that can be solved by our level. Such as taking extra care during our work in the

factory, wearing comfortable shoe and clothing even though we were not supplied with any kind

of working clothes from the factory .but the rest problems were above our level so we couldn’t

do anything about it.



Chapter Three

3 Overall Benefits Gained From the Internship

3.1 Learned Practical Skills during Internship

Throughout the whole internship program we were able to experience the theoretical knowledge

we acquired during the past three years practically. The theoretical knowledge we had was

helpful in order to successfully accomplish our filed work.in addition to the theoretical

knowledge we had we were able to get practical skill from the field environment and the workers

which was a great deal.

Some of the practical skills we gain throughout our internship period are

Process controlThe main practical skill we acquired in metehara sugar factory was the skill of process controlling based on the given operational parameters and set points. Each plant have its own control highly equipped stations where qualified personnel are assigned to control the whole process in and prevent any kind of malfunction.so during our stay there we were able to identify what parameters to control and what measure to take if any error occurs.

Different kinds of machineries and their use in sugar production

At the factory there were many machineries which facilitate the sugar production some of them

were manually operated while the rest were operated automatically. This machineries in

combination with the factory labor force perform the production of sugar from raw cane up to the

final sugar crystal.so during our internship we were able to identify the working principle and the

parameters of these machineries.

Laboratory analysis on the different materials of the processes.

The factory laboratory performs different kinds of analysis on the different materials during the

process in order to check if the process products and parameters are meeting the standard of

ICUMSA (international commission for uniform method of sugar analysis).and we were able to

carry out some tests in the laboratory such as:



Cane analysis Dry substance and moisture analysis Polarization Bagasse analysis Juice analysis Reducing sugar analysis Boiler water analysis Physical properties analysis Inorganic substance analysis

Generation (production) of chemicals to be used in different process.In metehara sugar factory there are two stations that produce so2 and lime (milk of lime) for different processes.so we were able to work on the production of so2 and milk of lime from raw sulfur and raw calcium oxide respectively.

Identified problems and solution suggested

The other skill we learned was identifying problems that occur in the company. This

problems may be caused by the recklessness of the employees, maintenance problems, or

because of the worn out and old machineries in use.so after being able to identify we were

able to come up with so suggestions.

Production of ethanol and bio compost from the byproduct coming from sugar production.

After we completed our work on sugar production we were able to see the production of

ethanol from molasses and the production of bio compost from filter cake and vinasse (by

product of ethanol)

Water treatment

The other thing we gained knowledge from was the water treatment plant. This plant is used

to treat water coming from Awash River and use it in the production of ethanol.

Data recording techniques

Even though it was not that much of related with our field of study we were able to gain some

skill on how to record data. Such as, how to record incoming cane from farm in order to correlate

it later with the produced sugar.



3.2 Up Grading Theoretical Knowledge

The internship class does not only depend on the practical aspect it depends on both ,theoretical

and practical knowledge, both types of knowledge are important and both helped us to do

better .theoretical knowledge helps to understand and upgrade or increase what had learned in

class, it enables us to understand the process done in practice because we had the advantage of

on theoretical knowledge, we couldn’t cope up with our internship class if we had no theoretical

knowledge.it also enabled us to read more and upgrade our theoretical knowledge.in the

internship class we were able to upgrade our knowledge beyond from what we have learned in

class some of this are.

Heat transfer equipment’s Design of shell and tube and working principles Report writing Multiple effect evaporators and Working principles Distillation column and their working principles

We learned those things in exclusive because it is hard to read and understand everything from

books and asking some peoples.so the internship class in metehara sugar factory enabled us to

upgrade and improve our theoretical knowledge.

3.3 Upgrading Interpersonal Communication Skill

Interpersonal communication skill is an exchange of information between two or more people. It

is also an area of study. Communication is sharing or exchanging information or ideas with

others in order to get some messages and knowledge. Communication skills are developed and

may be enhanced or improved with increased knowledge and practice. During interpersonal

communication, there is message sending and message receiving.

The communications systems within metehara sugar factory have taken on a large role in the

achievement of profitability and efficiency. A basic understanding of communication systems is

beneficial to all section of the factory as they all play a part in the success of the production of

sugar. Sugar factory is one of the places that ask a good communication skill. That means

communication is an important and the main key way of learning.



Good communication is important in the factory and it can appear in different forms as

Speaking Writing Reading and Listening.

In metehara sugar factory we gained many experience due to communication with other workers

like chemical engineers, operators, supervisors and Forman. We also gain an experience in order

to increase our self-reliance using interpersonal communication by using the following methods.

By trying demonstrate and work independently, By communicate effectively, By demonstrate flexibility, By solving problem

In some place/case it is very difficult to talk workers and ask them what we want because of that

they underestimate us and sometimes they are not eager to tell. But we improve and know how to

communicate with different classes of workers in the site.

3.4 Improving Team Playing Skill

Teamwork is prerequisite to the success of any organization, and to the success of the individuals

who work there. It’s vital you keep developing the skills that enable you to collaborate well with

colleagues and clients

Team playing has a major important in order to achieve success in the process that involves a

group of people. Team playing skill for sugar production, especially for engineers, involve in

every piece of task and achieving good team playing skill is essential for Effective completion of

tasks and Increasing productivity.

We have been use this skill in the campus during projects, assignments and group works. But this

skill is more organized and serious in sugar factory than in campus. In the factory the work is

already a team work. Without team work and understanding it is difficult to achieve the goal that

has been planned. And it needs more closeness of workers to solve problems arise in different

aspects misunderstanding in the process or working methodology.



We also work together in the factory as a team to get more understanding and share ideas. More

or less we improve our team work status by working together with different professionals,

students and workers.

3.5 Improving Leadership Skill

Leadership is the activity of leading a group of people or organization or the ability to this.

Leadership involves establishing a clear version, sharing that version with others so that they will

follow willingly providing information. We had individually seen that the employees are

controlled and supervised; they have very good communication skill with their respective

supervisors and controlled in each and every gap of their working hour .The supervisors write

and report /record any kind of mistake. Leadership is a skill to guide, control and monitor

peoples. For effective leadership we understood that personal values like confidence, effective

communication and devotion are very important.

In order to improve our leadership skill one must consider the following steps:

Improve communication skills; be able to communicate clearly and efficiently. Maintain a positive attitude to respect employees. Set goals and be passionate to achieve those goals and share that goals to the team. Live in accordance with your morals and values. Take responsibilities for your action and learn from your failures and weaknesses. Continue to educate and improve yourself. Know and utilize your strength and gifts. Motivate others to achieve good work and greatness. Listening to others. Be technically proficient (skilled with different knowledge‘s). Ensure that tasks are understood, supervised, and accomplished.

In the factory it was really hard for us to lead because we went there to learn things, but in the

future we hope to be a good leader and achieve a great amount of work to fulfil our goal. But one

thing is for sure that being a good leader is hard it takes a lot of commitment and responsibility.

3.6 knowledge Gained In terms of Work Ethics and Related Issues

Work ethics is the overall quality in one‘s behavior towards appreciating the process of work

flow and performing well on the job. During our internship program we have managed to do our

job with a high spirit and motivation so that there was a smooth flow of activities in the wok



environment. Work ethics involve such characteristics as honesty, Responsibility, reliability,

accountability and etc.

So in our stay in metehara sugar factory we highly tried to achieve all the expected work ethics.

Such as punctuality; we were assigned in morning and afternoon shift we had respected our work

time and this helped us to improve our punctuality skills. In addition to this we had always

respected the rules and regulation of the factory. The other work ethics we gained was

dedication, when we observed the work environment all the workers were highly dedicated for

their work this give us a lesson on how we have to be committed to our work.

Character was also the other work ethics we had gained from our internship program. Most of

the workers were highly disciplined, pushing themselves to complete work task instead of

requiring others to intervene. They were also very honest and trust worthy. These strong

characters were also a great ethical lesson to us.

Generally we can say that we had gained so many good and ethical behaviors during our

internship program which will help us in the near future when we join the work environment.

3.7 Entrepreneurship Skills

What we gained from metehara sugar factory in terms of entrepreneurship skill are

The ability to manage and raise money

The factory generates electric power by using steam energy which underrates the cost for electric

power from ELPA

Byproducts are not just discarded; they are further used to produce other useful products which

raise the money of the factory. These are

Final molasses:-to produce ethanol Bagasse:-as a fuel for boiler plant to produce steam energy Viennese and filter cake:-to produce a fertilizer, which helps for the growth of the cane

and minimizes the cost for fertilizers by 45%

The Ability to be Productive and Remove Stress

The factory works with 3 shifts, the shift switches within a week so, there is like distribution of

working time that way the workers do their job without stress and the factory without resting

which helps to rise its production



The Ability to Identify Strength, Weakness and To Deal With Failure

In MSF the operator writes down the activity of the shift in the remark book, that way the shift

coordinators and the unit leaders will be able to identify the weakness and strength of the shift

and provides the right correction and modification for the problem

The Ability to Hire Effective personnel and to Train New Staff

MSF hired well learned chemical engineers, mechanical engineer and chemists, they works

together with the experienced operators and benefit the factory to produce a product by means of

the science. And when there is a new staff to be hired the experienced operators and the

engineers together trains them .Then after they gets the proper training they will be measured by

a test and if they passes they will be hired.



Chapter Four

4.1 Conclusion

Internship is a bridge between the theoretical knowledge and the practical training. We all who

take the internship class go to factories that already working in order to produce different

products. The responsibilities of the hosting company are to teach student and shape them as a

member of their factory in four month. We were able to apply theoretical knowledge practically.

This allows as enhancing our knowledge. During these past four months we have been able to

see the different theoretical aspects, methodologies and how to produce sugar.

The mission of our internship hosting company is to Produce sugar of standard quality at a least possible cost and satisfy its customers, Provide best service to the society at large, Remain competitive and profitable, To be environmentally friendly Provide affordable living standard to its employees and Utilizes all resources at disposal

The factory is a well-organized one with a lot of skilled manpower. The work flow is so

organized that it made the company so chosen by many customers. It is the most experienced

sugar factory with in the area. In our hosting company there are advisors and they help us who

took the internship session in this company in acquiring different knowledge in different plants

(section). They collaborate with supervisors and operators in order to teach us how the factory is

operated.

This program played an important role to break the conventional thought that sugar production

can be only implemented by students who hold a degree or people who have an experience in

sugar production, ethanol and bio compost. We were able to acquire a high level of confidence

to deal with problems that arise in production of sugar.

Since we took our internship session inmetehara sugar factory we get the opportunity to work in

different section of the company other than sugar production like ethanol plant, bio compost etc.

Which helps us to gain more knowledge by seeing and asking what the employs Work and what

is their main responsibilities.



Generally we were able to know the main procedures, parameters and uses of sugar production,

ethanol plant & bio compost. There were some challenges but we were able to manage it by

increasing our personal theoretical and interpersonal communications skills.

4.2 Recommendation

4.2.1 Recommendation to the Company

Most works in the factory needs careful attention and successive supervision of works because in

the factory we use different toxic chemicals for production process, and also operated under very

high temperature and pressure so the employees needs to be careful and require successive

supervision to avoid safety problem. In the metehara sugar factory there are works which is

performed in the way that must not to be performed. Such works leads to safety problem, loose

of human power if its degree of effect is high and it leads to economy and property loss. Thus we

recommend for the company the following:

Improper cane handling and preparation. Here the weigh bridge is inaccurate, the yard is not clean and it is dusty, cane is not washed, generally unclean and poor cane handling and preparation process, inefficient knives. These total problems in cane handling and preparation unit affect the whole unit’s capacity and efficiency.

Poor juice extraction process and extracted juice handling. Here because several equipment malfunction extraction is not good and we lose sucrose with bagasse. Diffuser not work correctly, there is mill setting problems, etc. the extracted juice is not handled properly and inversion of sucrose to simple sugar is take place this is undesired. And juice is leaked everywhere .This is the result of lack of maintenance and carelessness to properly repair the machines and lack of equipment for maintenance.

Here our system is adiabatic, that means heat is not transferred to the surrounding from the system or vice versa. But the real situation in MSF is far from this. There is steam leakage, lack of insulation. This makes shortage of energy, hot environment and bad working condition for worker. So working conditions must be improved, like insulation must be considered, suitable ac must be installed to avoid the hot environment.

Leakage is main problem here in MSF. Prepared cane, bagasse, extracted juice, clarified juice, syrup, massecuite, molasses, sugar, steam, condensate water etc. all these are leaked because of old pipes. Lot of consideration must take place in order to renew or repair, stop, reduce the leakage problem.

There is no feed water and waste water treatment plant. This in turn has several effects. Scale is formed in pipe this reduce heat transfer rate create high pressure inside pipe and finally the pipes are damaged. Corrosion it affects pipes severely. Pumps, heaters are damaged. In MSF boiler pipes damage is best example. .n this case different projects must be done in order to plant water treatment in economical and feasible way



Loss of sugar/sucrose with final bagasse, filter cake and final molasses. Heat energy loss at boiler plant with smock through chimney and that released to

environment. Has two negative effects; first energy is lost second environment is badly affected. There must be some treatment mechanism.

Ethanol plant in MSF, produce 3000L/hr. RS and 1L is cost 14.5 birr. So we get 43500 birr per hour and 1.044000 million birr per day. The problem here is energy. If there is no electrical energy from ELPA, there is no production because it dependence on ELPA and we lost so many birr. Solution is needed quickly.

Usemodern machineryorequipment forhigh productivityand to finish works ontime.

There are different problems in this factory most of the problems rise because the factory has

worked for the past 52 years and it’s so old that the machineries /equipment are old must be

repaired or maintained with highly experienced and trusted engineers otherwise the factory has

proven to reduce its efficiency every year and this leads to suppress demand and decrease the

profit.

4.2.2 Safety work in the Factory

Human lifeisirreplaceableNowdays ithasbecome common to hear accidentson the process

industry.Themore the accidents are becoming redundantthe responsibilityof the supervisors

and the attentiontogive to safetyofthe workersis progressingtobe

preponderant.Therefore,itcannotbe deniedto workon increasingthe safetycondition in the

factory.The most effective wayofavoidingrisks is the preventive strategy. As the health

professionals use to say ‘preventionsbetter than cure, itis morethanreasonableto be abiding

bysuch motto. Lessconcerned safetyrule, regulationand trainingare amongthe problemin the

factory.

Safetyofallworkingstaffsand visitors shouldbe observed to ahighestcare. Infliction

ofinjuryshallbe minimized. Forthispriorreadinessis veryimportant.The safety managementwillbe

carried outwitha specialsupervisor to beassigned in the factory.Safetyof the workers and visitors

willbe managed inthefollowingstrategies;

Preventive Strategy:Successwould onlybe possible if there are workers, whocan give

theirpotential outputwithoutfearofanyunanticipated risks. While they’restrivingto achieve

thetargeted result,they maynotbe focused ontheirsafetymatters. Thepreventive strategyinvolves

thefollowingelements:



Orientation:Allworkingand visitingpeoplemustbe oriented aboutsafetybefore they enter the

factory.Orientationmustinclude on howto workwith machinesandequipment, the possible

accident theymay inflictand what rules and procedures theyhave to follow when workingwith, it

must also consider not working or touching any machineries unless or otherwise they are told to

do so by their supervisors,

Signage:Importantsignsthatcould remind people who are movingwithinthe

workinglocationshould be situatedina place whereeverybodycan see orlook.

Firm Temporary Works: - All temporaryworks like maintenance should be identified.

Lighting:Appropriatelightingmustbe delivered,ifthereneedto workon the night times.

4.4.3 Accident Administration

After involvingtheabove stated methodsofprevention ofaccident, but some accidents might occur

so acute accident administration might be necessary.

First Aid:Addresser, who hasrelevantprofessionalbackground,willbeassigned on siteforany

possible firstaid.

Secondary Treatment:Some accidents mayrequire secondarytreatment

4.4.4 Recommendation totheSchool

Thestudentgoesto the internship class are owned bythe universityor the schooland are given tothe

companiesthatuseorteachus throughout themonths. So, before and afterwe go to thecompaniesthe

schoolmustfulfillthe following:

Evaluatingand supervisingstudentsastheyareinthefactory bysending mentors on time. Coursesthatareappropriateforthesite workbeforethe internship class is important. Workingwiththecompaniescloselyto addressmore knowledge to the student. Sendingthe studentontime totheirhostingcompany. Organizingstudentsthose reside inthesame placetocreate ateamplayingskilland provide

group-workingenvironmentinordertoshareideas.

Mostlythoselisted problemchallengesthe studentnot to perform well and explore/upgrade knowledge.



Appendix

Appendix A: Basic Terminologies

Ash: Solid residue determined gravimetrically after incineration in the presence of oxygen. In

analysis of sugar products, sulfuric acid is added to the sample, and this residue as sulfated ash

heated to 525 °C is taken to be a measure of the inorganic constituents. Sometimes it determined

indirectly by measurement of electrical conductivity of the product in solution.

Bagasse: Cane residue leaving mills after extraction of juice.

Brix: Measure of dissolved solids in sugar, juice, liquor or syrup using a refractometer,

otherwise referred to as refractometric dry solids. For solutions containing only sugar and water,

Brix = % sugar by mass.

Casandra: Tubular or plate heating element in a vacuum pan or evaporator vessel.

Centrifugal: Centrifuge used to separate sugar from mother liquor.

Clarifier: Apparatus for the separation by sedimentation of suspended solids from a turbid sugar

solution.

Clarified Juice: Juice from clarifier also referred to as clear juice.

Color: Attenuation index, determined by absorption of light under defined conditions. Generally

Cooling Crystallization: Crystallization by cooling of the massecuite.

Crystal Content: Proportion by mass of crystals in massecuite, often expressed as a percentage,

and referred to total massecuite mass or to massecuite dry substance (Brix).

Crystallization: Nucleation and growth of crystals.

Dissolved Solids: are all solute material which is in solution, including sucrose,

monosaccharaides, ash and other organic impurities.

Dry Substance: A measure of total solids obtained from evaporating a solution or massecuite

under vacuum to dryness. Also it referred to as total solids by drying or dry solids.



Evaporator Effect: One of a system of evaporators operating in series as a multiple effect

system (e.g. First effect, second effect). Condensates and vapors are labeled correspondingly

(e.g., first condensate and vapor one: condensate and vapor from the first effect respectively).

Extraction: Proportion of sugar extracted from cane in the extraction plant; equals mass of sugar

in raw juice as a percentage of mass of sugar in cane.

False Grain: Undesirable small crystals, formed spontaneously by secondary nucleation when

the super-saturation during crystallization is too high.

Fiber: The dry fibrous insoluble structure of the cane plant. Generally taken to mean all

insoluble material in the cane delivered to a mill, and therefore includes soil or other extraneous

insoluble matter in cane.

Filter Cake: Material retained on the filter screens and discharged from the filters after filtering

clarifier muds.

Filtrate: Liquid passed through the screens of the filters.

Flocculants: Polyelectrolyte in solution added to juice to assist clarification.

Imbibition: The process of adding imbibition water to the extraction plant to increase extraction.

Water added is called imbibition water.

Liming: Process step in juice purification in which lime is introduced into the sugar juice in the

form of milk of lime or lime saccharide solution.

Liquor: sugar syrup, a term generally used in sugar refining.

Massecuite: The mixture of crystals and mother liquor resulting from the crystallization process.

Massecuites are classified according to purity as A, C, or D massecuites.

Molasses: The mother liquor separated from the crystals by centrifuging. A, C or D molasses is

derived from the corresponding massecuites. C molasses is also referred to as final molasses.

Mother Liquor: Liquid phase in the massecuite during crystallization; refers to syrup or liquor

in which the crystals are growing.

Non-sucrose: Dissolved solids contained in any process stream other than sucrose.



Non-sugar: Common overall term for dissolved solids other than sugar contained in any process

stream.

Polarization: (or the apparent sucrose content expressed as a mass percent measured by the

optical rotation of polarized light passing through a sugar solution. This is accurate only for pure

sucrose solutions.

Press Water: Juice expressed from dewatering mills after a diffuser.

Purity: The true purity is the sucrose content as a percent of the dry substance or dissolved

solids content. The solids consist of sugar plus non-sucrose components such as invert, ash, and

colorants. Apparent purity is expressed as polarization divided by refractometer Brix multiplied

by 100.

Reducing Sugars: Generally referred to and/or interpreted as invert sugar, determined by

measuring reducing substance content by laboratory analysis.

Saturation: A sugar solution at saturation will not dissolve any more crystals at the temperature

of the solution.

Seed: Suspension of fine crystals in saturated solution of alcohol, or the initial grain resulting

from seeding in a vacuum pan.

Strike: Massecuite as a completed boiling, all of which is discharged from the pan.

Sugar: Term for the saccharide sucrose and products of the sugar industry, essentially composed

of sucrose.

Sulphitation: Introduction of sulfur dioxide into juice or liquor.

Super-saturation: The degree to which the sucrose content in solution is greater than the

sucrose content in a saturated solution.

Suspended Solids: Insoluble solids in juice or other liquid, removable by mechanical means.

Syrup: The concentrated juice from the evaporators.

Trash: Cane tops, leaves, dead stalks of cane and any other vegetable matter delivered with the

cane.



Appendix B: Material balance

There are some assumptions and standards in Metehara sugar factory. The standards are listed in

the following table.

Table 8:Some standards for material balance

Standards Values

Cane processed per day 5000tonn

Cane processed per 200tonn

Fiber content %cane 13%

Sucrose content % cane 14%

Non-sucrose content %cane 0.5%

Water content %cane 70%

Ash and other impurities content % cane 2.5%

Imbibition water % cane 25-30%

Final bagasse moisture content 40-50%

Lime added per ton of cane 0.5 Kg

Evaporator load 75-80%

Vacuum pressure of vacuum plant 0.2666 bar

Assumptions

All units we use in the calculation ton per our Take basic 200ton/hr. There is no loss Working hour 24hr.



General material balance

Since the process is continuous, steady and non-reactive the general material balance is look like

this.

Input =output

C+Imb+lime=B+FC+E1+E2+Mo+S

Since direct measurement of these values are very difficult we follow the component method

starting from the starting point. And we discuss the result. But first

Thus 200 ton cane feed per hour contain

Water =140 ton

Sucrose=28 ton

Non-sucrose/reducing sugar=1.0ton

Fiber=26ton

Ash and other impurities=5 ton



Table 9:Calculation for extraction, clarification and evaporation unit

1 Milling plant 2 Clarification 3 Evaporation

Assume

Imb=25% cane

Milling and Diffusion

efficiency=0.95

Bagasse moisture

content=50%

Imb =0.25*200=50

Sucrose

ex=0.95*28=26.6

Un-Extracted

sucrose=1.4

Bagasse water

content=26+1.4=27.4

Bagasse amount=

26F+1.4S+27.4B

=54.8

Output and input to

clarification unit are

input

Water= 140+50-27.4=162.6

Sucrose=26.6

RS=1.0

Impurity=5.0

Total juice=195.2ton/hr.

Milk of lime=0.5kg/ton of

cane=0.10ton

Assume efficiency of clarifier to

remove impurity=0.96

Thus slug

removed=0.96*5.0+0.10=4.9ton/hr.

Remaining impurities=0.1

Total CJ=195.2-4.9=190.3

%of

solid=(26.6+1+0.1/190.3)*100=14.56

%

Input

W=162.6

Sucrose=26.6

Imp =0.1

Rs=1.0

Total juice=190.3

Assume evaporation load as 0.76

Thus evaporated

water=0.76*190.3=144.628

Water remained in juice=162.6-

144.628=17.927

Total solution=190.3-144.628=45.672

% of

solid=(26.6+0.1+1.0/45.672)*100=60.6

5

4. Crystallizer

Inputs

W=17.927

Sucrose=26.6



Reducing sugar= 1.0

Imp=0.1

Assume 0.92 sucrose is recover as crystal with respect to input sucrose

And 0.33 reducing sugar is recovered as crystal

Thus the weight of sucrose= 0.92*26.6=24.472

Weight of reducing sugar=0.33*1.0=0.33

Assume moisture associated with both is =0.31

Sucrose in molasses=26.6-24.472=2.128

Reducing sugar in molasses=1.0-0.33=0.67

Total sugar in molasses= 2.128+0.67=2.798

Water required to dissolve this=2.798/2.6287=1.064

Water to be evaporated=17.927-0.31-1.064=16.553

4 Centrifugation

Input

Solid= (S+RS+moisture+Imp) =25.217

Molasses=2.798+1.064=3.862

Assume 0.1 molasses is adheres to crystal

Thus the weight of molasses that added to solid=0.1*3.862=0.3862

Total sugar crystal=25.217+0.3862=25.6032

Total molasses=3.862-0.3862=3.4758

Now we can calculate the general material balance in both rate form and amount for as following

C+Imb+lime=B+FC+E1+E2+Mo+S

C=200ton/hr.

Imb water=50ton/hr.



Milk of lime=0.1ton/hr.

B=54.8ton/hr.

FC=4.9ton/hr.

E1=144.628ton/hr.

E2 =16.553ton/hr.

Mo =3.4758ton/hr.

S =25.6032ton/hr.

(200+50+0.10=54.8+4.9+144.628+16.553+25.6032+3.4758)ton/hr………………correct

Input and output ton per hr. Input and output ton per

day

Quintal per day Real value quintal

per day

Cane 200 4800 48000 30000-35000

Imbibition water 50 1200 12000

Milk of lime 0.1 2.4 24

Bagasse 54.8 1315.2 13152

Filter cake 4.9 117.6 1176

Water evaporated at

evaporation plant 144.628

3471.072 34710.72

Water evaporated at

vacuum plant 16.553

397.272 3972.72

Final molasses 3.4758 83.4192 834.192

Sugar crystal 25.6032 614.4768 6144.768 1800-3000

NB. This is the standard of the company but the reality is far from the result shown above.



References

1. Hugot. (1986),hand book of cane sugar engineering, third, completely revised, edition. Elevier-Amsterdam-Oxford-New york-tokyo

2. D.P Kulkarni. (1995), Cane sugar manufacture in India. The sugar technologist association of India, New Delhi, India

3. Peter Rein. (2007), cane sugar engineering. Verlas Dr. Albert Bartens KG-Berlin4. Sugar Engineering and Manufacturing Training team. (April,2014), Ethiopian Sugar

corporation training materialson cane handling and preparation, cane juice extraction, clarification and filtration, evaporation, vacuum plant, centrifugation and sugar finishing and boiler water. Wonji-shoa, Ethiopia
