Choosing the most appropriate lubricant for pulp and paper mills
With paper machinery often operating at speeds more than 2,000 m/min and steam temperatures exceeding 200°C (392°F), the equipment used in pulp and paper mills is continually placed under extreme pressure to perform. As a result, it is important for companies to select advanced lubricants, including greases, which can operate effectively in this environment. In line with the very specific demands of pulp and paper operations, it is vital to choose the most appropriate grease to protect equipment and help ensure a trouble-free operation. When selecting a grease, factors such as base oil type, viscosity, thickener type, stability of the composition and operating temperature must all be considered in order to ensure that the most appropriate grease is selected to reduce costs and maximise productivity.
Greases for Pulp and Paper Operations
Advanced synthetic greases are now available which have been specifically designed for severe paper machine applications, where high-temperature environments and exposure to different qualities of water are prevalent. These advanced greases have the potential to help pulp and paper companies build a competitive advantage into their operation by helping to reduce the overall energy consumption and increase the productivity of a plant. Paper machine greases have multiple purposes, from lubricating moving parts to protecting against rust and corrosion. They also provide anti-wear performance to prevent premature machinery wear and provide protection for softer metal components. Paper machine greases need to tolerate a wide variety of corrosive and aggressive process waters and particulate contamination without significant impact on the performance of the grease.
Recent advancements in technology have resulted in the development of supreme performance synthetic greases, which are scientifically formulated for paper bearing applications. One such advancement is the Mobilith SHC PM™ Series, which offers a number of performance advantages to pulp and paper operators. The Mobilith SHC PM™ Series comprises synthetic high performance paper machine greases for wet- and dry-end bearing applications. Engineered for the harsh operating environments of paper machine bearing applications, the Mobilith SHC PM™ Series is designed specifically for severe paper machine applications where high-temperature environments and exposure to different qualities of water are prevalent.
Productivity on a roll
The recent experience of a pulp and paper operator in Russia demonstrates how a fully synthetic grease, such as the Mobilith SHC PM™ Series, can help deliver significant performance and financial benefits for a business. The factory was previously using a local competitor grease for bearing lubrication at the wet section of the paper machine, where frequent equipment failures were an issue. An analysis highlighted that the grease in use was experiencing high water washout rates as well as a severe lack of thermal stability at high temperatures, leading to premature wear of the bearings. As an alternative to the existing grease lubrication solution, an ExxonMobil Field Engineer recommended the use of Mobilith SHC PM™ Series 460. This recommendation was based on its outstanding structural stability in hostile water environments and its ability to provide resistance to water washout.
The decision was also informed by the Mobilith SHC PM 460's ability to perform at high temperatures up to 150°C. Following the switch to Mobilith SHC PM 460, the pulp and paper factory has benefited from a 90 percent reduction in unscheduled downtime. As a result, the company's costs have been substantially reduced and productivity increased, providing an overall improvement in profitability for the business. Another pulp and paper mill to benefit from the Mobilith SHC PM™ Series is based in Finland. The paper mill had previously been using two lithium-complex greases in its central lubrication system. Due to the incompatibility of these grease products, the greases were either becoming hardened and thick, or losing consistency and beginning to leak. As a result, the protection and performance of the mill's equipment was compromised. Following a comprehensive analysis of the mill's operations and equipment maintenance practices, a team of ExxonMobil technical advisors recommended the use of Mobilith SHC PM 220 in the central lubrication system. Following the switch, the paper mill observed immediate performance and cost saving improvements.
Specifically engineered with a synthetic base fluid and high-quality lithium-complex thickener, the Mobilith SHC PM 220 grease withstood the high operating temperatures in the mill and provided consistent protection of the bearing housing. The risk of bearing damage has been reduced, increasing overall operating life and reducing the need for frequent maintenance requirements. A reduction of the bearing operating temperatures by 10 - 20°C has also been noted, which will help to prolong equipment life. In the competitive pulp and paper marketplace it is essential that paper machines run with minimal downtime and maximum productivity. Even a small increase in machine productivity can mean the difference between profit and loss. The selection of high quality, well balanced and compatible greases, therefore, can play a crucial role in ensuring the success and profitability of a pulp and paper operation.
Umut Urkun
Industrial Marketing Advisor, EAME
