7.1 INTRODUCTION
In the manufacture of cement, proportioning of raw materials is strictly controlled at all stages to ensure the quality of product well exceeds the quality requirements stipulated in the relevant standard specification, ISO 9000.
Besides, researches and various tests are keep doing by the Quality Control Team in order to keep and at the same time enhancing the quality products ordered by customers. Any complaints regarding to their products are taken serious and further inspections are done to find the main cause of the problem so that the same problem will not occur again.
ISO 9000
ISO 14001
OHSAS 18001
Figure 7.1: Qualifications obtained by Lafarge Malayan Cement
81 7.2 HARD GRAIN INDEX
Hard Grain Index Test is done to ensure the quality of product in term of fineness. Good quality of product has not too large nor too small. Good fineness product will provide cement that will be easily mixed and has great strength.
Step Pictures Descriptions
1
Clinker is filtered until 600 micron clinker is obtained
2
The clinker then is weighed
3
By using Hard Grove, the clinker is crushed to small
4
Disc Mill Grinding is used to crush the clinker till 45 micron
5 The index is calculated by using information
obtained
Table 7.1: List of procedures
82 7.3 SIEVE TEST
Sieve test is done in order to determine the size of limestone that has been crushed by limestone crushers. The appropriate size of limestone is necessary so that the limestone can be crushed and mixed easily in millers. The most suitable size of limestone for milling is less than 25mm however limestone size up to 50mm is still acceptable.
Figure 7.2: List of procedures
Samples obtained is filtered by 100mm,
50mm and 25mm filters
For each of the size obtained, the weight
of it is measured.
The percentage of the weight to the overal
weight is calculated
83 7.4 RESIDUE TEST
Residue test is done to ensure the fineness of product that has been produced. This test is done for both Normal Blaine product and High Blaine product. For Normal Blaine product, the 2.5g samples is needed while for High Blaine product the 5g samples is needed.
Figure 7.3: List of procedures
STEP 1
• Normal Blaine product is weighed to the respective weight needed
STEP 2
• The sample then is filtered to obtain 60 micron residue
STEP 3
• The residue is weighed back
STEP 4
• By using formula, the product residue
is calculated
84 7.5 DROP TEST
Drop test is a test where the feed rate of each raw materials entering into machines is calculated. The feed rate is very important in achieving the desired product with optimum power consumption.
Figure 7.4: List of procedures
STEP 1
• Speed of belt conveyor is measured by a contact tachometer
STEP 2 • Power of the belt conveyor is isolated
STEP 3 • A 1m long is marked on the belt conveyor
STEP 4
• Material in the 1m range is put onto the weigher
STEP 5 • The weight of material is recorded
STEP 6
• By using a formula, the feed rate is
calculated
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CHAPTER 8: PROJECTS
8.1 SEALING AIR FAN FOR CEMENT MILL 4
8.1.1 BACKGROUND
This project covers the following scope of works:
To purchase and install one unit air sealing fan complete with accessories (filter, ducting etc) to prevent dust from entering into Cement Mill 4 (CM4) combiflex system.
LANGKAWI PLANT CM4DATA
Cement mill no. 4 (CM4) was commissioned by Krupp Polysius AG in 1997. The mill that has shell diameter 5200 mm and nominal length 15,000 mm is driven by 2 units of gear box supplied by Flender AG. In the combiflex system (consist of gear box, girth gear and supporting equipment) the lubrication oil is sharing between gear box and girth gear by means of one LO unit system.
Since commissioned, the gear box had been overhauled a few times due to high vibration as follows:
Year overhauled Reason
Nov 2007 High Vibration
May 2008 Output shaft bearing damage
Aug 2009 Input shaft crack – Total Overhauled (CAPEX) May 2010 High vibration (Gear Misalignment)
May 2011 High vibration (CAPEX) Jan 2012 Gear box replaced (CAPEX)
Table 8.1: Maintenance done for Cement Mill
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After some various brain storming sessions with Lafarge Malayan Cement engineers, dust ingression into gearbox oil circulation system was shortlisted as one of the main factors causing the failure. In addition to precautions of reducing suspended dust and improved lubrication filters, it was decided to incorporate positive pressure dust suppression systems in gear-gearbox guard sealing.
On most occasions, the Combiflex arrangement is at the mill feed end making the Combiflex system highly vulnerable to dust contamination. The ingress dust through seal combines with oil to form clots at the lubrication nozzles for mesh lubrication and bearing lubrication resulting in lubrication and gearbox components failure. Due to dynamic application of seal, 100% theoretical sealing of dust ingress is not possible. Additionally, the abrasive nature of clinker dust in the inlet aggravates the situation further.
The only way to effect 100% sealing from dust ingress in Combiflex system is by creating a positive air pressure inside the combined gear and gearbox guard. This can be achieved by installing low pressure high volume blower (forced draft) with discharge connections directly into the common guard seal areas. The blower inlet is mounted with suction filter which is regularly cleaned. The individual pipes branching off to the guard are to be mounted with flow adjustment dampers. This will help in ensuring uniform flow of air in all sealing areas.
This main objective of this project is to sustain Cement Mill 4 operation and improve mill reliability by securing CM4 operation from major failure caused by gears damage due to oil contamination.
87 8.1.2 OBJECTIVE
This main objective of this project is to sustain Cement Mill 4 operation and improve mill reliability.
8.1.3 EXPECTED BENEFITS
Main benefit is to secure CM4 operation from major failure caused by gears damage due oil contamination.
8.1.4 COST JUSTIFICATION
The justification for installation of sealing air fan is Strict Sustaining Capital as this work is essential to sustain the operation of Cement Mill no 4 (CM4). The project cost can be justified based on loss of maintenance cost due to gearbox repaired as follows
No Equip Year Overhaul
Duration (day)
Cost (RM)
Specialist Contractor Rental Spare
part Total
For year 2011, CM4 mill inlet lubrication oil had been renewed 4 times due to oil badly contaminated which cost of RM 140 000.
Table 8.2: Project cost justified based on loss of maintenance cost
88 8.1.5 RESOURCE REQUIREMENTS
Budget
Total estimated investment of RM 262,500.00 is required for this project to be implemented.
The details breakdown of the budget is as follows:
No Part Description Cost (RM) Remark
1 Sealing air fan (1 unit) 40,000 Quotation
2 Air filtering chamber 30,000 Estimation
3 Ducting and other accessories 80,000 Estimation
4 Electrical parts 20,000 Estimation
5 Contractor for installation 80,000 Estimation
6 Contingency cost (5%) 12,500
TOTAL 262,500
Table 8.3: Detail breakdown
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8.2 TRACING PRESSURE VESSEL TANK IN CEMENT MILL SECTION
8.2.1 INTRODUCTION
In manufacture of cement, the usage of compressed air is very important. The compressed air is used by almost all parts available in plant especially machines. In Lafarge Malayan Cement Langkawi Plant, compressed air is generated by 6 units of compressor located in Silo 4 and Silo 5. From the Silos, the compressed air is flowed to each of the sections in plants and it then will be distributed to each of parts and machines needed by pressure vessel tank.
Pressure vessel tank is a closed container designed to hold gases or liquids in transferring compressed air throughout the entire sections in plant. As pressure may drop when flowing throughout the system, the pressure vessel tank is important in keep maintaining the required pressure needed thus machines can keep operating with suitable pressure.
Figure 8.1: A pressure vessel
90 8.2.2 PROBLEM
Damages and malfunction of pressure vessel tanks may cause disruption on operating machines like millers, grinders and dust collectors. Moreover, a long period taken to trace and repair the damage pressure vessels may cause the damages of machines plus unavoidable accidents like pressure vessel tank explosion to occur. This might seem to be a simple problem however if the problems occur, it might cost lot to plant.
8.2.3 SOLUTION
In order to solve the problems, an initiative to trace each of the pressure vessels in Langkawi plant is started by Process Department and well supported by LMC Langkawi Safety and Health Department.
Each of the pressure vessel tanks is traced and the condition of each tanks are remarked in a proper document for official reference later on. For more easily, a diagram indicates all tanks available in Cement Mill Sections are drawn. This helps engineers to know where a pressure vessel tank is located if problems occur.
The official reference document and drawing are attached in Appendix.
91
Figure 8.2: Drawing of Pressure Vessel Tanks for Cement Mill 4
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8.3 MEASURING THE ACTUAL FAN PERFORMANCE CURVE FOR LK1 AND LK2
8.3.1 INTRODUCTION
Since each type and size of fan has different characteristics, fan performance curve must be developed by the fan manufacturers.
A fan performance curve is a graphical presentation of the performance of a fan. Usually it covers the entire range from free delivery (no obstruction to flow) to no delivery (an air tight system with no air flowing). Generally, these curves are determined by laboratory tests, conducted according to an appropriate industry test standard, and obtained under ideal conditions.
The fan curves used to predict the pressure-flow rate performance of each fan. With the curve also, engineers can determine which fan gives the volumetric flow rate needed for their system pressure drop. In additions, engineers also can choose fan that has its peak efficiency at or near to their operating point.
For this special task, I was asked to calculate the actual fan performance curve for Raw Mill EP fan in Line 2 and Cooler Exhaust Fan. The produced curve will help engineers at Process Department in analyzing the actual performance at the existing fan thus can identify and overcome problems occur.
Formula that has been used;
93 8.3.2 LK2–RAW MILL EPFAN
Figure 8.3: Raw Mill EP fan curve
Figure 8.4: Performance Curve plotted for RM EP Fan
94 8.3.3 LK2–COOLER EXHAUST FAN
Figure 8.5: Cooler Exhaust Fan curve
Figure 8.6: Performance Curve plotted for Cooler Exhaust Fan
95 8.3.4 DOPOL WASTE GAS FAN
Figure 8.7: Dopol Waste Gas Fan curve
Figure 8.8: Performance Curve plotted for Dopol Waste Gas Fan
96 8.3.5 RAW MILL FAN
Figure 8.9: Raw Mill Fan curve
Figure 8.10: Performance Curve plotted for Raw Mill Fan
97
CHAPTER 9: DISCUSSIONS
9.1 SAFETY AT WORKPLACE
Heavy industries may be a great place to work and earn big salaries however with the speeds in which events occur mixed with the sum of possible safety hazards, it might be our own grave.
The Main Dangers at Work Place
Dangers are elsewhere in the site of heavy industries. Dangers could come from our own negligence, others’ negligence or the condition of the site itself. It can be avoided if all site hazards are well avoided and safety precautions are seriously taken.
The top hazards recorded in heavy industry are as follows:
1. Trip and fall
This item always makes the top of the list for heavy industry site hazards. Falls from equipment, scaffolding, and other high places are dangerous and far too common to occur.
Figure 9.1: Signs of hazards
98 2. Scaffolding
This also causes falls and if put together improperly can cause injuries and death. People seldom think about heavy industrial equipment safety with respect to equipment that moves but standstill equipment can be just as dangerous when not used properly.
3. Electrical appliances
This hazard involves all the electrical appliances used seldom in site. Explosion, electrical shock or electrocution may occur on these appliances if it is not well maintenance. If this occurs, serious injury and fatality may occur. To prevent this from occur in their workplace, continuous inspection need to be executed to all electrical appliances used in their site.
4. Over-exertion and stress
This repetitive use injury has been recorded as the fastest growing type of injury in the workplace. It is caused by repeating the same actions or maintaining the same position for a long time. The effects of this problem are unconscious and injuries at wrist hand or back.
5. Excessive Noise
Most of heavy industries workers are exposed to excessive noise that comes from operating machines. The louder the noise, the more damage it can cause. The excessive noise may cause permanent injury like hearing loss either progressively, or by the exposures over a long period of time. To overcome this, workers need to wear ear buds when working in a noise site.
99
9.1.1 PERSONAL PROTECTIVE EQUIPMENT (PPE)
PPE which stands for Personal Protective Equipment is defined as equipment which is intended to be worn or held by a person at work and it protects him against one or more risks to his health or safety.
Figure 9.2: Basic Personal Protective Equipments
Employers have basic duties concerning the provision and use of personal protective equipment (PPE) at work and they have no right to ask for money from an employee for that equipment, whether it is returnable or not. If employment has been terminated and the employee keeps the PPE without any permission, as long as it has been made clear in the contract, employer may be able to deduct the cost of replacement from any wages owed.
To allow the right type of PPE to be chosen, employer need to be carefully consider the different hazards in the workplace. This will enable them to access which type of PPE are suitable to protect them against hazard for the job need to be done.
100 9.1.2 SAFETY REPORTING SYSTEM (SRS)
Safety Reporting System (SRS) is an online database which allows members of Lafarge to share and learn effective and efficiently and at the same time follow up the corrective actions. Analysis of accident is circulated on weekly basis to all employees throughout the organization worldwide.
For this reporting system, each members of Lafarge Cement is needed to submit at least 2 reports on any near miss or faulty observed in plant. The report shall be based on members of Lafarge, contractors, or the plant condition itself which if it is continually ignored will cause accidents later on.
The structure of the report will be picture of the situations, who involve, time taken, the location and lastly the estimated cause if it happens. The report then will be sent to the Safety and Health Department via Lafarge e-mail and it will be strictly checked and recorded by the department.
To encourage members of Lafarge Cement to join this program and send more reports monthly, a reward system has been introduced. In this reward system designed by Safety and Health Department, members who recorded to send higher than 2 reports will be rewarded with a voucher. This RM50 voucher can be used by members to buy any items at Teow Soon Huat Shopping Mall located in Kuah, Langkawi.
This reward system has encourages Lafarge members to submit more reports thus indirectly increases the awareness on the important of safety and hazards at the workplace amongst them. With the increasing number of report submitted by members compared to the last few years, the objective is totally achieved.
101 9.2 ENVIRONMENTAL ISSUE
9.2.1 LAFARGE GROUP POLICIES
For Lafarge Cement Group, they keep believe that they will only succeed in the long term if their actions respect the common interest. This means they must not comply with laws but also conduct business consistent with sustainable development principles. Thus, they are committed to the protection of the environment, human health and well-being, to the migration of climate change and the conservation of nature.
With objective of to ensure the continued improvement of environmental performance, they aim to use energy and natural resources more efficiently, minimize the production of waste, harmful air emissions, and water discharge while seeking ways to preserve landscape and biological diversity.
In order to implement these objectives, Lafarge commits to:
1. Operations
Operate their facilities in a manner that meets local laws, standards and regulations and the environmental management systems requirements.
Minimize the use of non-renewable resources (feasible and safe) and replace them with substitute raw materials (alternative fuels or biomass).
Minimize the amount of hazardous and other wastes generated, reuse and recycle
materials where practicable and dispose of wastes using safe and responsible methods.
Implement programs to prevent accidental releases like having emergency response action programs in place at all sites.
102 2. Resources, Training, Research
Provide adequate financial and human resources, employee training and
awareness rising to facilitate continuous improvement in environmental performance.
Take the necessary steps, including sponsoring research, to improve employee’s knowledge of the environmental impacts of their processes and products.
3. Procurement
Evaluate the environmental values and policies of subcontractor and supplier candidates as part of the selection process.
Require subcontractors and suppliers to respect our environmental, health and
safety values and comply with Lafarge policies and procedures when present at plant.
4. Stakeholder relations
Provide stakeholders routinely with environmental information about Lafarge operations and products in an open manner.
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9.2.2 LAFARGE MALAYAN CEMENT INITIATIVES
Conserving natural resources – Biomass to energy
Objective
To reduce the cement plant’s consumption of fossil fuel and provide a disposal solution for the organic wastes generated by palm oil production.
Context
Malaysia is the world’s leading producer of palm oil. Waste from this production (mainly the palm kernel shells) poses a disposal problem for growers, and is commonly landfilled or burned with no energy recovery. At the same time, the Rawang and Kanthan cement plants use large quantities of coal which is imported and used as their primary fuel.
Figure 9.3: CO2 emissions from combustion of the biomass are considered to be “carbon neutral”.
104 Solution
Lafarge Cement decided to use palm kernel shells as a secondary fuel in its cement kiln.
The equipment needed to receive, sort and grind the palm kernel shells, as well as the necessary belt conveyors, was installed. The shells are now fed directly into the precalciner.
Results
This substitution is a means of reclaiming the biomass for energy at a rate of 10% of overall energy consumption. By reducing the amount of coal burned, the two plants have cut their aggregate CO2 emissions by 140,000 metric tons per year, given that emissions generated by combustion of the biomass are considered “carbon neutral”. Finally, the reduction in imports also means less transport-related pollution.
Figure 9.4: Palm kernel shells are substituted for some of the coal.
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Lafarge Roofing – CoolRoof insulating roof system
Objective
To define a construction system appropriate for tropical climates which control heat transmission from the roof to the living areas of the house.
Context
In warm climates, construction features can make a significant contribution to efforts to control the indoor temperature of housing units. In conventional construction, the sun’s radiation on the roof tiles causes heat to be transmitted from the roof to the attic or loft area, and then down into the living areas. If the house is air conditioned, high
In warm climates, construction features can make a significant contribution to efforts to control the indoor temperature of housing units. In conventional construction, the sun’s radiation on the roof tiles causes heat to be transmitted from the roof to the attic or loft area, and then down into the living areas. If the house is air conditioned, high