Ethiopian Institute of Technology - Mekelle

Department of Mechanical Engineering

Energy auditing in raw mill

By Micheale mekonen FST/UR043/99

Supervisor Mesele hayelom (Ir)

Hosting Company: Messebo Building Materials Production plc.Department of Mechanical EngineeringMekelle October 20111

AcknowledgmentFirst and foremost I would like to express my heart felt gratitude to ir mesele for his dedicated collaboration with valuable, continuous suggestions and ideas during the energy audit process.I would like also to express my sincere appreciation to engineers tekle, aksumawi and raw mill attendants, those who helped me in Messebo cement factory during the internship. My deep appreciation and thanks goes to engineer kasahun who was always gives me courage for a very challenge I had passed. Finally, I am very glad to say thanks for my colleagues and all those people who contribute their own hand in my internship.

Micheale Mekonen 2011

Executive summary

Based on, the new five years curriculum of the Mekelle University, one semester is allotted for Industrial linkage. Because of this, we have spent the fourth year second semester at Messebo building materials production plc.In our stay at Messebo building materials production plc, we have worked in different sections of the company under different leaders. Working under these leaders, we have tried to observe different tasks that are performed in the company and find problems that the workers encounter during their job operation.After identifying the problems, we have tried to solve some of the problems by ourselves and proposed ways of solving the problems for those that we couldnt solve by our selves.While doing this, we have been able to upgrade our practical and theoretical skills and improve our team working abilities.We have also been able to identify the opportunities present.

Table of ContentsAcknowledgmentiExecutive summaryiiCHAPTER ONE11. Brief History Of The Company11.1 Background of the company11.2The main products and the suppliers11.3 Vision, Mission, Objectives and Targets21.4 Organizational Structure of the factory31.5 structure of messebo building maaterials production p.l.c41.6 The over all process of the factory5CHAPTER TWO122. Proposal on energy auditing in raw mill122.1. Introduction122.2 Problem statement122.3. Research topic122.4. Research output132.5. Methodology13CHAPTER THREE143. Energy auditing on raw mill143.1 Mass and energy analysis143.2 Mass balance on sepax separator163.3 Energy balance173.4 Energy balance in sepax separator19Chapter Four20Conclusion20Recommendation21References22

CHAPTER ONE1. Brief History Of The Company1.1 Background of the companyMessebo cement factory is located in Mekelle town in the Tigray regional administrative 790km. Far from A.A (capital city) of Ethiopia.The factory is located 11 km for from Mekelle town near to Messebo hills with the number employees about 600 employees established with 1.2 billion Ethiopian birr. The factors taken in the consideration to build the factory are the fulfillment raw materials availability, cement market, energy supply, and infrastructure requirement and investment incentives.The feasibility study fro Messebo cement factory was conducted by Austro plan, Austrian Engineering Company and was sponsored by Tigray development association. The company was established around Mekelle with high raw material potentials.With the expanding construction business through out the country w/c demands cement as one of its indispensable inputs with out the construction activity would hardly be possible to make it sustainable. Meeting this demand at a fair price with highest quality is the objective of MCF1.2The main products and the suppliers The factory has developed appropriate sales out lets to ensure that its customers are actually beneficiaries. The factorys main product is ordinary Portland cement (opc) with its distinctive features, remains being competitive in the market. More over, its product is over standard. Besides, the factory has already provide to customers with different cement type such as, Portland pozzolana cement (PPC) with EN 197 standard. The product of the factory entered to the market at country level latterly, but according to the data collected, it gains vigorous witnesses in satisfying its users in all market and additionally the factory product has received a certification of the cement quality immediately after the commencement of production from the Ethiopian quality and standard authority and working now for TOM certification. ISO 9001-2000.Messebo cement factory has already developed its strategies that would enable it work with every segment of the market when it commences distribution of its product in February 1992 E.C particularly. Wholesalers retailers of cement, constructors, dry cargo transporters, government and noon government organizations undertaking construction activities and the society at large, are the ones which Messebo cement factory is looking for ward to establishing a storing tie with.The factory technology is the leading technology of 21st century, which was supplied and erected by the best manufacture of cement machinery in the world FLSmith CO. of Denmark.The annual production capacity of the factory is 600000 tones of ordinary Portland cement.The factorys distribution centers are located at the factory compound, Addis Ababa, baherdar and Dessei stores, besides it has a direct distribution channels to Gonder, Combolcha and Woldia etc, (Feasibility study, 1993).1.3 Vision, Mission, Objectives and TargetsAccording to the factorys business plan, Messebo Cement factory has the following mission statement.1.3.1 The factorys visionThe vision id designed to be, as to become fully competitive by building its internal capacity, enhance creation fulfill national demands and to examples of modern systems and high standards of work culture.1.3.2 The factorys MissionThe mission of the factory is to shortly assume its existence and support the continuously growing construction industry with supply to construction materials of acceptable quality and reasonable price while also broadening its property ownership.1.3.3 Objective of Messebo Cement FactoryThe overwhelming expanding construction business via out the country demands cement as one of its indispensable inputs with which the construction activity would hardly be possible. Meeting this demand at fair with higher quality, this remains to be our objective. In line with, the factory has the following objectives:

To create sustainable market by supplying competitive products that fulfill Customers requirements Enhance property ownership To continuously develop modern and scientific methodology, work, culture and systems Develop human resources and crate job opportunity Create conductive work environment Enhance regional development Control or remove causes for environment pollution1.3.4 Strategies of Messebo Cement FactoryThe factory established the following strategies in fulfilling its activities. By creating broad an sustainable market by supplying competitive products that fulfils customers requirements.To continuously develop modern and scientific work method, work culture and system. Create conductive work environment.Enhancing property ownershipControl or remove causes for environment pollution1.4 Organizational Structure of the factoryThe factory (Messebo Cement Factory) consists for top to bottom, the board of directors, the general manger, department, and branch offices.As it is clearly seen on the chart the departments are Production Maintenance Quality control Management representative and human resource Finance Procurement and supply MarketingHuman resources:- Messebo Cement Factory has highly professional committed and innovative workforce that works to its best, to deliver products with high quality standards on time to its customers. At the current moment of time the factory has exactly 850 employees. Among which 90.2% are permanent and 9.2% are contract employees there are seven departments to fulfill it s objectives..

1.5 structure of messebo building maaterials production p.l.c.

GENERAL MANAGER

LEGAL SERVICEAUDIT SERVICE

IT SERVICE

EXCUTIVE SECRETARY

Division general manager administration and controlDivision general manager process and quality controlDivision general manager mechanical and maintenanceDivision general manager electrical and maintenance

MARKETING PROCESS MECHANIAL MAINTENANCE ELECTRICAL FINANCE QUARY AND CRASHER DEPARTMENT MAINTENANCE HUMANE RESOURS QUALITY CONTROL DEPARTMENT PROCESS AND SUPPLY

1.6 The overall process of the factory1.6.1 Quarrying and crushingThe quarry (where the mining processes performed) is located .. km away from the plant has the main raw materials to such as, limestone and shale that is estimated to last for years, the other raw materials (ironore, silica sand, gypsum and pozzolanna (pumice)) are brought from near by places .limestone provides calcium oxide and some of the other oxides, while shale and the other materials (silicasand,iron ore)provide most of silicon,aluminium and iron oxide required for the manufacture of Portland cement.A few materials away from the quarry there is one fls hammer crusher which can crush 550 .the crusher reduces 85% of the rock lumps from a 2meter size down to lessthan 25 mm. 1.6.2. Raw material preparationIn messebo cement factory there is closed longitudinal material storage hall with 342m area used to store all the raw materials mentioned above.There are about 7 piles (previously and 9 piles now (limestone additive and pozzollana piles adds). One common stacker is used for stacking nine raw materials which have been crushed in the crusher. Limestone and shale which need homogenizing effect are stacked chevron method of stacking and the other piles which need no homogenization effect are stacked after cone shell method. The separate reclaimers one for limestone and the other for shell are installed to homogenize the particulate materials and to convey the homogenized material from the piles to the out going conveyor. Silica sand and iron ore and loaded by loader on the hopper which beneath it has a conveyor that discharges them to the out going belt conveyor.Gypsum, limestone additive and pumice are brought to the cement by the loader1.6.3. ProportioningIn the department four intermediates bins for limestone, shale, and silica sand and iron ore storage are placed. Beneath each bin there are dosimat feeders which adjust their speed according to the signal given from the QCX software from the laboratory in this way the raw materials are proportioned in order to satisfy the final chemistry requirement.That is the chemistry of each raw materials analyzed by x-ray analysis is fed to the software, based on this soft ware will calculate the proportioning in percent of mass of the raw materials, this will be sent to plc type system and this system will give the proportioning signal to each dosimat, each dosimat will then vary their speed based on the load sensed by the load cell poisoned there. Every hour, samples (accumulated at sampler for continuous one hour) from raw mill product will be analyzed and fed to the software to correct any deviation (from the set point inserted in the computer) that may occur due to different reasons. Therefore the system does not allow uniform chemistry that may have a negative effect in burning the raw meal at kiln.

1.6.4 Raw material grinding The raw material grinding systems equipped with a ball mill (diameter = 5, drying chamber length=2.2. and grinding chamber length =8.22m). The nominal capacity of the mill is 180t/h, the finesse of the product is 15% residual on 90m sieve and moisture content in the raw meal is less than 1%. In Messebo cement factory the exhaust gas from pre-heater is used to dry the raw materials from average moisture content of 4% to less than 1% in the raw meal.As mentioned above there are four feeding bins in raw material proportioning station (limestone bin, shale bin, sand stone bin and iron ore bin).The four kinds of raw materials are fed to a common belt conveyor according to the pre-set proportioning rations by corresponding weighing feeder (dosimat feeder). Then the raw material on the conveyor is fed to the ball mill. In the raw mill drying and grinding take place and the very fine materials will go with the air as separation air and the Coarse ones go to the air slide at the out let of the mill then to bucket elevator and then finally to the separator through an air slide.The ground material is then classified by a sepax separator. The coarse parties returned to the mill for further grinding and the fine part as product is carried out with the gas and collected (separated) by two cyclone separators. The pre-dedusted gas is vented out and sent to some recirculated as separation air and some to the Electrostatic precipitator for further clean u and sent to the environment then after.The raw meal collected by the two cyclones is transported to then raw meal homogenization silo (CF silo, or controlled flow silo) by air slide and elevator1.6.5. Raw meal homogenizing and kiln feeding systemKiln feeding system is mainly comprised of cf-silo and LOW (loss of weight) unit,cf silo is for raw meal storage and homogenizing. Kiln feed measuring is mainly accomplished by LOW system. There are 7 extraction holes at the bottom of cf silo,3 rotary blowers are selected. And the blowers controlled by the programmable logic control, will alternatively aerate 3 segments (place at 3 different extraction holes), and simultaneously material is extracted from these out let holes.Three load cells are provided at the bottom of LOW hopper, which are used to measure materials weight in the hopper.Kiln feed control is fulfilled by measuring the reduced material quantity in the hopper with in certain period of time (during emptying period).and mathematical model during filling period.The adjustable motorized gate is controlled by signal from the programmable control unit, the load cells in the tank, and set values for the feed rate from the operator at CCR.Metered kiln feed is conveyed to the top of the preheated by an air slide and then by two air lift blowers.1.6.6. The waste gas treatment systemWhenever the kiln is in normal operation and the raw mill is stopped, the exhaust gases induced by ID fan are treated by gas conditioning tower to around 150-160 .if both kiln and raw mill are in opration,hot gas is supplied to raw mill for drying purpose.Gases not used in raw mill are passing the GCT and joining the gases from raw mill, where after the entire gas flow is dedusted in raw mill/kiln ESP.The dust precipitated in the raw mill/kiln filter is returned to either cf silo or preheater.The cooler excess air is de-dusted in a separate ESP specially designed or clinker dust. The recuperated dust is returned to the clinker transport system.

1.6.7. Clinker burning and clinker transportationThe kiln burning system is composed of a 3.7557m with inline calciner and a single five stage preheater. The average specific heat consumption of the system is 710-750 kcal/kg clinker. after the raw meal is pre heated in pre heater stage cyclone 1 to 5 are precalcined in precalciner,the caco3 calcining rate in the kiln inlet can reach 95%.th remaining 5% of the calcinations and clinkerazation process will be taken place inside kiln. the ratio of firing oil burned in the kiln for clinkerization and the precalcined is 4:6. A grate cooler is applied to clinker cooling by cooler fans. The clinker getting out of the cooler is commuted by the built in hammer crusher and then carried to clinker storage by means of bucket conveyor. The exit gas from the cooler pertly goes to kiln as secondary air and partly to calciner as tertiary air. The surplus part is emitted to the atmosphere after cleaned by a cooler EP.1.6.8. Clinker storageA clinker storage silo with capacity of 15000tons and an open yard with a capacity of 20000 tons are built in the plant. Under the clinker silo, the rod gate and the motorized discharging gate are installed. The clinker discharged by the equipment is fed to different belt conveyor correspondingly, then carried to the clinker feed bin in cement grinding plant by means of belt conveyor.1.6.9. Cement grindingA closed circuit grinding is applied. The main equipment consists of a 4.612m double compartment tube mill and sepax separator. This mill at this time produces two types of cement namely ordinary Portland cement (opc) and pozzolana Portland cement (ppc).OPC compromises 90% clinker, 5%additives (limestone) and 5% (gypsum).PPC compromises 70% of clinker,25% pozzolana and 5% gypsum.The capacity of the mill is 105-120t/h for OPC cement and 135-140t/h for PPC cement when the specific surface of the product is 2800cm2/g to 3000 cm2/g.The clinker, additive (limestone, pozzolana) and gypsum are fed by the corresponding belt weighting feeder (dosimat feeder) to a common belt conveyor then the belt conveyor feed them to the tube mill.The ground material is carried to the sepax rotor via air slides and bucket elevator. The separator will classify the ground material in to two parts the course and the fine. The coarse material is fed back to the tube mill via air slides. The product from the separator is carried to a cyclone by means of gas stream and is collected by it. Most of the air leaving the cyclones is recycled to the sepax separator; the remaining air is cleaned in bag filter before released to the atmosphere via the chimney. Product as cement is conveyed to cement silos via air slides, belt conveyors, screw conveyor and bucket conveyor 1.6.10. Cement storageTwo 16m concrete silos are setup as cement storage facilities; each of them has a storage capacity of 10,000ton. Air ducts are erected on the bottom of the silo for aeration of the cement fluidization. The air is supplied to these ducts by root blowers. On the bottom of each cement silo a discharging unit of manual gate and a pneumatic flow control gate is installed. The discharge from these gates is transported to the cement packing system via air slides and bucket elevator. Connecting with the discharging units, there is bulk loader for both silos installed for loading the bulk cement to the Lorries.The cement flow rate to the loader can be controlled by a flow control gate, which is mounted beside the discharging unit,1.6.11. Cement packingThe packing line of products in powder form is equipped with different elements/machines.The principal elements of the packing line are;1. Vibrating screen2. Feed hopper3. Rotary feeder 4. Packing machine5. Discharge beltFlow of material in the packing plant;The flow of material rises from the bucket elevator to reach the vibrating screen, where is screened, to be settled in the storage hopper. The former is equipped with control systems (called sensors) placed inside the hopper. These sensors control the extraction system and keep the level as the steady as possible.Then the flow of materials passes through the rotary vane feeder equipped with alternate gear to adjust the level of materials in the packet hopper. The sensor, by which the bag packer is equipped, serves the purpose of the checking the rotary vane feeder in order to keep the level as steady as possible. The flow of materials is in then directed to the spouts; most part of it is packed in the bag, whereas a very small of scraps, in the form of dust, over flows.The dust is sucked up and collected, by means of a sucking chute, in the lower hopper. The reject is then separated: the dust is gathered by screw conveyors and led back into the conveying cycle.The packing bag cement is sent out and guided to the bag cleaner and bag cutter (for those less than 50kg) by means of belt conveyor. The cleaned bags are carried by a roller conveyor and a belt conveyor to truck loaders conveyor, and then loader or trucks.The weight tolerance of bagged cement is guaranteed by the automatic control system

Internship The challenges that I had facedDuring, the internship time I had to expose to a lot of challenges that eventually support me to know what and how I had to do. This starts which seems as ease as like asking where to find the office of human resource department (HRD) up to talking with our supervisor about the internship. I really remember it while I was arriving the first day in Messebo cement factory .we didnt have any idea about the over all process and these huge machineries as well. Besides, to this the working environment is too dusty and noisy especially when you are become close to these machines.Even though, such working environment were strange for me I had to adopt them as fast as possible in order to accomplish for what I had been there. The second problem that I had to face was to interact with workers who are already engaged.After a time I introduce a lot of workers in every division, I start to feel like I was there for many years. There for, this enables me to extract information in a well defined manner in almost all sections.Finally, the most problems were about the datas and manuals that put in practice and the working principles of some part of machines which is necessary for the analysis of identified problems.

Benefits that I gained form this internship Unfortunately, our predecessors didnt get such an interesting chance. So, feel my self like lucky man.When we come to the main aim of internship, I think I achieved all of them what are expected from me.During the internship time I got a lot of experience which will be valuable and useful in my future career. In terms of practical skill, I have been improving my practical skill through participation when there were maintenances of machinesI was take parting when there had been a break down of machines so, I used to see and gain significant skill. For instance, a maintenances of bucket elevators, belt conveyors and rotary kilns and one of the main benefits that, I gained was up grading my theoretical knowledge which, I was familiar in thermodynamics, heat transfer and strength of materials..etcBesides of, improving my practical skills and upgrading theoretical knowledge, I also used to improve my communication skill with my advisor and some operators who were willing to told me the operating principles of these machines ,the way how they maintains. And with every one who has been working on the cement factory.Most of times we were working with operators in a brotherhood manner so, I think I became familiar with team and leadership skills.Consequently, I also became aware of what it has to be my duty and responsibility.Finally, I have been inspired to do my own work without any expectation of hiring.

CHAPTER TWO2. Proposal on energy auditing in raw mill2.1. IntroductionThe raw mill are a horizontal clinkers with a powerful internal metal shielding that contains tons of balls mills inside used to crush the raw materials.As the raw mill rotates these ball mills fall dawn, hit the material particles and the impact force will divided it in two and more pieces granules which form what is called raw meal.Currently, the raw mills have a capacity of 180tons/hour for crushing raw materials to the required size and quality.Finally, the raw meal is conveyed to special silos where the homogenization process is completed.2.2 Problem statementThe production of raw materials using grinding of materials is the most energy intensive production process is one cement industry consuming an approximately 45-80kwh/t corresponding to approximately 50-75% of the total consumption of electrical energy of 90-130kwh/t clinker.As a result of this, optimal raw material operation in terms of material balance (mass and energy) is therefore essential.

2.3. Research topic The raw mil units have three (3) main features;i. Raw mill unitii. Separatoriii. Cyclones 2.3.1 Research topic units The raw mill is the where the grinding of raw material is takes places in order to produce the required amount of raw meals.The sepax separator is used in a closed circuit grinding plant for separation of the fine from the coarse material which is received from the mill.Subsequently, the fine fraction is separated in to 4(four) cyclones arranged in planetary system and at this stage the fines are referred to as a finished product. The coarse fraction is recycled to the mill inlet for further grinding.Consequently, there is a heat loss in the mills due to conduction through and insignificant radiation from the shell mill.Besides the moisture content of the raw material is and because of the 85-95% efficiency of the four (4) separator cyclones there exists mass and energy un balance.2.4. Research outputSince, the main aim of the raw mill is to produce sufficient raw feed for keeping the kiln in continuous operation. As a result of the optimum mass and energy balance (material balance) on raw mill is going to enable us in order to secure the desired output of clinker at lowest possible energy consumption.A uniform clinker output at a high level ensures a lower consumption of energy on the pyro process as well.It improves thermal efficiency of the energy intensive process on cement industry which is grinding (raw mill).It also improves the pyro processes and related material (mass) operations and environmental benefits to the overall kiln operation.2.5. MethodologyThe previous data that has been collected and the quantification of the numerical specification for the mass and energy analysis that is going to carried out.The inputs (raw materials), energy consumption and output like emissions, loss and the main product (raw meals) will also illustrate.

CHAPTER THREE3. Energy auditing on raw millThe raw material grinding systems equipped with a ball mill (diameter = 5, drying chamber length=2.2. and grinding chamber length =8.22m). The nominal capacity of the mill is 180t/h, the finesse of the product is 15% residual on 90m sieve and moisture content in the raw meal is less than 1%. In Messebo cement factory the exhaust gas from pre-heater is used to dry the raw materials from average moisture content of 4% to less than 1% in the raw meal.As mentioned above there are four feeding bins in raw material proportioning station (limestone bin, shale bin, sand stone bin and iron ore bin).The four kinds of raw materials are fed to a common belt conveyor according to the pre-set proportioning rations by corresponding weighing feeder (dosimat feeder). Then the raw material on the conveyor is fed to the ball mill. In the raw mill drying and grinding take place and the very fine materials will go with the air as separation air and the Coarse ones go to the air slide at the out let of the mill then to bucket elevator and then finally to the separator through an air slide.The ground material is then classified by a sepax separator. The coarse parties returned to the mill for further grinding and the fine part as product is carried out with the gas and collected (separated) by two cyclone separators. The pre-dedusted gas is vented out and sent to some recirculated as separation air and some to the Electrostatic precipitator for further clean u and sent to the environment then after.The raw meal collected by the two cyclones is transported to then raw meal homogenization silo (CF silo, or controlled flow silo) by air slide and elevator.

3.1 Mass and energy analysis On raw mill inlet we have three mass inputs; I. Mass of materialsII. Mass of coarse returnIII. Mass of hot flue gas from kiln

Mass of materils1 Mass of matrials2 Mass of return coarse Hot flue gas mass of gas leaving mill T= 324 T= 99.63 Pressure= 2mbar pressure= 32 mbar Fig.1. Control volume, various streams and components for raw mill.At certain time we have a feed rate of materials in % Table.1 feed rate of in put materialsType of materialsFeed rate in %

Limestone75.2%

Shale19.7%

Silica sand3.8%

Iron ore1.3%

From design capacity of raw mill for materials = 180t/h3.1.1 Input materials from proportioning unit Table.2 analysis of input materialsLimestone 1= 1800.752=135.36 =135360 Shale2=180 0.197=

Silica sand3=1800.038=6840Iron ore4=180=

3.1.2 Hot gas (flue) from kilnThis gas is a dust laden gas Based on, dust balance

So, inlet dust quantity) 3.1.3 Return course from separatorHere, we have a return factor (0-20%)

3.1.4 Mass balance on raw mill exit=

So,=

gas leaving mill system is a sum of total incoming gas + vapour from water evaporated +

3.2 Mass balance on sepax separatorSepax separator unit

Gas which goes to ESP and fine materials

Return course to mill mass of materials2 Mass of gas (by-passed) dust laden gasFig.2 control volume of sepax separator.3.2.1 Mass balance on sepax separator

+ + = +

=+ + _

3.2.2 Mass of gas (by passed)This gas is by passed from the cyclones in order to use for further separation in separators Volumetric flow rate = (9000-10000) Density = 95() So,

After this, the product mass separated to dust mass which goes to ESP for dedusting and fine material which goes CF-SILO +

== _

3.3 Energy balance First, drying in mills takes place on drying chamber;3.3.1 Drying in millsA sensible heat supplied from the hot gas (flue) to input materials;

)

=716 A heat required to evaporate vapor from water (moisture content)= )

=464472kcal/kg 3.3.2 Heat in leakage Here, we have heat in leakage due to heat transfer (conduction type) from the system to the surrounding through the shell of raw mill.

Where, = (298 = -299.75k Area = Area =

Therefore,

097kj

=716 464472kcal/kg +097kj= 465259.09 We have a mill motor with 3000 kw power

We have also power consumption = Finally, using mass and energy conservation law;.1 +2

465259.09

3.4 Energy balance in sepax separatorA sensible heat load due to (from gas leaving mill and a gas by passed)

In sepax separator we have a motor with 300kw

We have also an exhaust fan with 400 kw

So, from the mass and energy conservation law1 +2

kj/hrFinally The Thermal Efficiency of raw mill is,Thermal Efficiency

Chapter FourConclusion Material quantities, as they pass through processing operations, can be described by material balances. Such balances are statements on the conservation of mass. Similarly, energy quantities can be described by energy balances, which are statements on the conservation of energy. If there is no accumulation, what goes into a process must come out. This is true for batch operation. It is equally true for continuous operation over any chosen time interval. Material and energy balances are very important in an industry. Material balances are fundamental to the control of processing, particularly in the control of yields of the products. The first material balances are determined in the exploratory stages of a new process, improved during pilot plant experiments when the process is being planned and tested, checked out when the plant is commissioned and then refined and maintained as a control instrument as production continues. When any changes occur in the process, the material balances need to be determined again. The increasing cost of energy has caused the industries to examine means of reducing energy consumption in processing. Energy balances are used in the examination of the various stages of a process, over the whole process and even extending over the total production system from the raw material to the finished product. Therefore used in everyday process management to maximize product yields and minimize costs.Material and Energy balances are important, since they make it possible to identify and quantify previously unknown losses and emissions. These balances are also useful for monitoring the improvements made in an ongoing project, while evaluating cost benefits. Raw materials and energy in any manufacturing activity are not only major cost components but also major sources of environmental pollution. Inefficient use of raw materials and energy in production processes are reflected as wastes.

Recommendation

Material and energy balances are very important in an industry. Material balances are fundamental to the control of processing, particularly in the control of yields of the products.When any changes occur in the process, the material balances need to be determined again. Material and Energy balances play a main role, since they make it possible to identify and quantify previously unknown losses and emissionsThese balances are also useful for monitoring the improvements made in an ongoing project, while evaluating cost benefits. Raw materials and energy in any manufacturing activity are not only major cost components but also major sources of environmental pollution. Inefficient use of raw materials and energy in production processes are reflected as wastes.There fore I proposed to have proper and continuous material and energy balances on raw mill in order to have produced sufficient raw feed for keeping the kiln in continuous operation. As a result of the optimum mass and energy balance (material balance) on raw mill is going to enable us in order to secure the desired output of clinker at lowest possible energy consumption.A uniform clinker output at a high level ensures a lower consumption of energy on the pyro process as well.It improves thermal efficiency of the energy intensive process on cement industry which is grinding (raw mill).It also the pyro processes and related material (mass) operations and environmental benefits to the overall kiln operation.Therefore used in everyday process management to maximize product yields and minimize costs.

References

F L S manual Manual of maintenances of ball mills Cengel and boles heat transfer text book Applied thermodynamics Moran, M.J. and Shapiro, H.N. 1995. Fundamentals of Engineering Thermodynamics, 3rd ed. John Wiley & Sons, New York.

Moran, M.J. Engineering Thermodynamics Mechanical Engineering Handbook Ed. Frank KreithBoca Raton: CRC Press LLC, 1999Hand book of cement manufacturers