The cement manufacturing process is heavy duty. Activities such as carrying mined limestone on quarry belts to the pyroprocessor where clinker is produced at high heat levels cause immense load and severe operating conditions for equipment such as kilns, ball mills, conveyors and quarry-side mobile plants. The cement making machinery works around the clock, subjecting its components like gearboxes and bearings to overheating and premature wear and tear. It is essential that care be taken and regular maintenance work be done for each of these equipment as the plant shall endure heavy financial and production losses if there is machinery failure, shutdown or loss of heat and energy in the mining area or manufacturing plants. To avoid such a situation and any unscheduled downtime, maintenance operators and managers invest in high performing lubricants, oils and greases that reduce the harm on machinery components. Lubricants at work Specially formulated lubricants are required at all stages of the cement making process, namely, extraction, crushing, conveying, grinding, clinker production, grinding and some general lubricants are needed for processes that happen in between. Selecting the right lubricant for every machinery can be challenging. It isn’t about the equipment but the environment in which the machinery is operating that can vary from season to season depending on the plant’s location. This factor must be carefully considered while deciding which lubricants, oils or greases would work best for the machinery and the plant’s systems. Conveyor Belts: Most often, cement plants are built close to the reserve of the raw material. Conveyor belts are used to transport mined raw materials from the quarry to the manufacturing plant. These belts are large in size and are driven by electric motors and require a good amount of power to displace heavy materials. This movement causes friction as well as wear and tear of the bearing and the belt. It is essential that these points are frequently greased to avoid this damage. It is also important to keep the grease in place as the conveyor belts are located in the open and are subject to a lot of dust that may cause further damage to the machinery. Often water resistant grease is chosen to prevent ingression of water in this transportation system. Gearboxes: Bearings and gearboxes are found within the crushers where raw materials travel to get crushed into smaller pieces. These components also deal with a lot of dust and pressure. A centralised greasing system is applicable in this setup as the bearings are located close to each other. These gearboxes generally are quite large and have a substantial oil capacity. The gear teeth often experience high shock loading, so extreme-pressure gear oil is frequently used for this reason. These crusher gear boxes benefit greatly from regular oil analysis and condition monitoring. A small amount of oil is taken as a sample, which lets the engineers understand about the wear and tear situation and plan accordingly to re-lubricate the machinery avoiding uncalled damage. Open Gears: A cement has different types of open gears that require different types of lubricants and application processes. The most important factor to consider while selecting a lubricant for gear boxes is to adhere to the revolution of the driven gear in order to offer the needed protection. Often, the lubrication is most required when the drive pinion mates. Rotary Kilns: Lubrication in rotary kilns is especially challenging due to the heat, load and slow rotation. For the gearbox, often synthetic oils are considered in a circulation system using heat transfer and filtration. However, it isn’t always necessary that the flow rate stays adequate and the heat transfer system stays efficient. For the bearings and gearbox of the rotary kilns the inherent frictional properties of certain types of synthetic lubricants may hold an advantage if they have high viscosity. The selection of a synthetic grease for the bearings is crucial as greased bearings will not provide the same cooling effects as a gearbox of the kiln lubricated with synthetic oil. Productivity enhancement Challenging operating conditions, continuous operations especially for the processing equipment such as the kilns, ball mills, conveyors and quarry-side mobile plants can lead to premature wear and tear or be subjected to overheating. Plant operators must maintain and choose the right lubricants to prevent any unscheduled downtime and costly additional maintenance, as well as safeguard their bottom line performance. Lubricants may cost upto 1 to 2 per cent of any cement company’s overall expense but play a key role in preventing major costs that may occur due to a faulty operation or shutdown. “We ensure that whichever lubricant we use does not contaminate the environment. The lubricants should be made in such a manner that they can be re-filtered, recycled and reused. The plants usually push for longer drain intervals so that it reduces the impact on the environment when discarded. The lubricants should also be made in such a manner that they can be used as a source of energy or can be burned in the kilns without causing pollution to the environment,” says Gopalkrishna Murthy, Vice-President, Zuari Cement Limited. The right advanced synthetic oils and greases can offer a number of benefits over conventional mineral-based alternatives, especially under severe conditions. For the ball mills and kilns, selecting a grease with high pressure additives and intense adhesion properties can be of prime importance. It would also be important to use a high viscosity oil in this system of the plant for thermal and oxidative protection. The right lubricant shall go a long way in efficient operations. A constant eye must be kept on the lubrication of gear boxes, bearing and drive pinions of the plant in order to ensure that they don’t undergo extreme friction or get damaged due to vibration. Every lubricant used for these components has a life of its own and comes with certain maintenance instructions. Adhering to those standards is key to continuous operations and avoiding uncalled for time-offs. Productivity of a cement plant is dependent on smooth operations, which in turn is dependent on the flawless functioning of plant machinery right from the point of extraction to packaging and exit of materials. Sustainability Goals The cement sustainability roadmap of 200 suggests that the 2050 target for carbon emission should be reduced to 420 kg per tonne as compared to 756 kg per tonne in 1990. The progress in this direction by the cement industry has been significant by using alternative fuels for clinker production or recycling waste to achieve their sustainable goals. Lubricants also play a role in achieving this target by every organisation. Specialty lubricants with innovative formulae have been created with research that help obtain operational excellence and support the balance of carbon emission in the industry. A systematic approach can lead the way of using these specialty lubricants in the cement plants if necessary to achieve the objectives. Switching over from a traditional lubricant for open gears to graphite free transparent lubricant can reduce its consumption significantly. Curated with a special formulation, this lubricant forms layers over the surface of the tooth flanks preventing its damage, pitting or scuffing. This layering has also shown enhanced productivity levels with efficiency in operations by improving temperature and vibration across the tooth flanks. On the other hand, switching over from mineral and oil based lubricants to bio lubricants can help achieve this goal of the industry. Commonly used lubricants for the cement industry contain around 80 to 95 per cent oil base derived from petroleum based products. In bio lubricants, these base oils are derived from plant sources, thus, considerably reducing the impact on the environment. Innovative lubricant manufacturers have developed cost-effective bio-lubricants. These eco-friendly lubricants can also be a great replacement for the lubricants that have graphite. It makes their handling and disposal safe for the work men and the environment. Multiple organisations are putting in an effort to create lubricants with special formulations that support the intense conditions the machinery of a cement plant endures. From dust, water, pressure, vibrations or weight, the right lubricant applied in the correct manner can make productivity efficient, can avoid untimely shut downs and support the cement industry to make their processes run in a smooth and timely manner. It is essential that close attention is paid in selection of these lubricants as well as their maintenance, drainage and disposal. - Kanika Mathur