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FP6

BIOMON Résumé de rapport

Project ID: 508208
Financé au titre de: FP6-SME
Pays: Germany

Final Report Summary - BIOMON (Towards long-life bio-lubricants using advanced design and monitoring tools)

The increasing use of bio-greases and bio-oils at machinery lubrication is aiming to reduce environmental burdens concerning usage and disposal of lubricants. The main objectives of the project were the following:
1. to develop environmentally friendly oils based on native and pentaerythritol esters and greases based on polyurea thickeners (DMI) combined with native esters for ball-screws, rolling bearings and gears;
2. to develop reliable procedures to analyse contaminated biodegradable oils and greases including biodegradability after use, and their application to mechanical components condition monitoring;
3. to evaluate the performance of mechanical components lubricated with environmental friendly lubricants;
4. to develop an intelligent system for condition monitoring strategies assessment in mechanical components lubricated with biodegradable fluids.

As a result of the project, four main 'applications' were targeted, that corresponded to:
- bio-degradable oils for operation at gear boxes;
- bio-degradable oils and greases for operation with rolling bearings;
- bio-degradable oils and greases for operation with screwballs;
- web-based software system for remote condition monitoring.

A complete set of biodegradable oils and greases to lubricate gears, rolling-bearings and ball-screw were developed. A complete experimental framework was set-up in order to indicate as accurately as possible whether bio-lubricants had better or equal performance to mineral products, and to establish adequate condition monitoring protocols.

A very novel task in this project was the study of artificial degradation and contamination of oils and greases in order to simulated degraded conditions that were difficult to obtain without extensive real operation.

For this purpose, a selection of the most suitable contaminants was made. Between all contaminants analysed on oil batches, the SAE fine test dust was the one, which gave more confident results (Dl and Ds), in respect to the calibration of ferrographic techniques.

Concerning artificial oxidation studies, a new artificial oxidation test was developed for biolubricants. The oxidation mechanism of biolubricants is rather different from a mineral's one, so in order to study the oxidation mechanism of bio-oils and the evaluation of their environmental properties, a new oxidation procedure was defined and used. An artificial oxidation test was developed for greases and biogreases. An artificial oxidation of mineral oils and greases was performed in order to select the most appropriate analytical techniques to monitor the mineral lubricants (oils and greases) degradation to establish thus condition monitoring strategies to control the mineral lubricants degradation. An artificial oxidation of biodegradable oils and greases was performed in order to select the most appropriate analytical techniques to monitor their degradation and to establish a good monitoring strategy.

During the project, there have been a comprehensive number of mechanical tests in both real and simulated (tribological) conditions. Regarding the tapered roller bearing application two different tribological tests were performed to analyse the tribological properties of reference (mineral) oil and bio-oil: ball on disc tests and bearing tests. Concerning the analysis of friction and wear properties of biogreases, three different tests were performed: four ball EP, SRV (wear) and rolling / sliding.

In the framework of this project the European Ecolabel was applied and some issues for the next revision have been studied and would be proposed:
1. Lubricants for gears should be considered and included in this label.
2. A new environmental criteria should be included in order to promote the lubricants regeneration: biodegradability during use.

It was considered that best way to disseminate the information concerning BIOMON project was by the development of special application reports - not scheduled at the beginning of the project- cross relating, for each of the three targeted components (screwballs, rolling bearings, gear boxes) the following information:
- bio-lubricants developments;
- lubricant analysis and degradation operations performed;
- mechanical tests and both simulated and real test benches.

Results and conclusions

The typical surface failure of tapered rolling bearings is concentrated in the corners between the races and the rollers. One of the main objectives was to improve the knowledge about the environmentally friendly lubrication of the tapered rolling bearings, to solve the main pitting problem, and to increase the life of the lubricant / rolling bearing and to establish the rules for condition monitoring of the biolubricant.

It was expected to increase a 10-20 % the speed limits and performance (20 % reduction of wear and life improvement) of actual lubricants. The use of advanced tools and the reduction of a 10 % the quantity of used lubricant, should help to decrease the maintenance cost a 30 %.

In order to get more realistic results, tribologycal tests were performed which simulated as close as possible real working conditions. Tapered roller bearings were tested in the Falex multispecimen tribotester and SRV tribometer. An Optimol model SRV tribometer was used to simulate reciprocating sliding motion, evaluating friction and wear characteristics of different fluids and materials.

After tribologycal test some conclusions have been obtained:
- Bio-oil produced lower temperatures which can be due to lower friction, even more, dust contaminated and oxidized bio-oil produced even lower temperatures.
- Reference oil produced high wear and temperatures when it was oxidized.

Two types of comparative analysis were carried out in order to compare the performance of the reference oil compared with bio-oil at different conditions. The use of a biodegradable lubricant instead of a commercial one did not alter significantly the characteristics of the bearing (geometry does not change significantly so that the load capacity of the bearing is the same) and its normal operation (vibrations, temperature, torque). Therefore, it was possible to replace conventional lubricants with other which had better environmental character and biodegradability.

In order to increase the performance of ball-screws in the upper and lower limits of speed, it was necessary to improve the lubrication and the lifetime of the system during time. Now, they use mineral based lubricants, but in order to help the Ball screws users to get the ISO 14000, it was necessary to offer to their customers high performance environmentally friendly lubricants. It was expected to increase a 10-20 % the speed limits and performance (20 % reduction of wear and life improvement) of actual lubricants. The use of advanced tools and the reduction of a 10 % the quantity of used lubricant, should help to decrease the maintenance cost a 30 %.

In order to get more realistic results, tribologycal tests were performed which simulate as close as possible real working conditions. Screwballs were tested in the Falex MS tribotester and four ball test.

After tribologycal test some conclusions were obtained:
- Both develops bio-oils presented good tribologycal properties, being the C8 slightly better and C9 cheaper. High levels of dust contamination (0.1 %) multiplied wear values (only) by a factor of 2.
- Bio-oil produced lower temperatures which could be due to lower friction. Even more, dust contaminated and oxidised bio-oil produced even lower temperatures.
- Reference oil produced high wear and temperatures when it was oxidised.

The influence of the lubricant type, traditional or biodegradable, oil or grease, on the performance and degradation of the ball screws was evaluated by means of three different test benches. The most fundamental type of test made at Shuton corresponded to the test bench named TORQUE 3000. This test bench is intended to measure the torque of the screwball. Results demonstrated that biodegradable greases represented a clear improvement with respect to reference oils, at main test performed over screw-balls.

One of the highest technological requirements for gears was to increase the speed limit and smoothness. In order to do this, the main problem was to improve the scuffing and pitting resistance of the gears by means of lubrication improvement. To check developed bio lubricants tests were carried out with the new biolubricants and collaborated in the establishment of the rules for maintenance.

In order to get more realistic results, tribologycal tests were performed which simulated as close as possible real working conditions. Gears were tested in the Falex MS tribotester and FZG test was carried out.

After tribologycal test some conclusions have been obtained. The developed new environmentally friendly gear oil GE8 (B8) accomplished all the objectives of the BIOMON project, it:
- was biodegradable;
- had low-toxicity additivation;
- was specified as CLP gear oils according to DIN 51517;
- had a competitive price / performance ratio.

The performance of the two lubricants was evaluated and the results obtained demonstrated that the new gear oil presented several advantages in relation to the reference mineral oil, it:
- had better gear wear performance;
- had better gear scuffing load carrying capacity;
- similar gear micropitting performance;
- lower gear power loss.

Performance monitoring of cutting-edge, ecologically-sensitive lubricants in high performance and critical plant items was now in the reach of engineering and maintenance teams thanks to powerful new maintenance planning and innovative condition monitoring software tools.

Developed through collaboration between United Kingdom condition monitoring specialists Monition Ltd and the Tekniker Institute of Tribology in Spain, the web-based software system enabled users to expertly design and operate maintenance management programs, plan advanced condition monitoring strategies and schedule maintenance tasks.

The innovative software tool and bio-degradable lubricants were a result of the two-year EC-funded BIOMON project. The software collected parameters concerning oil and vibration (with additional capability to input other parameters, such as temperature) to enable the analysis and diagnosis of component deterioration and developing faults. The software could automatically monitor health status, issuing alarms when parameters were breached and recommending adjustments to maintenance activity accordingly.

Among a series of more than 40 lubricant formulations developed and tested, a set of 6 prototype lubricants were fully formulated and tested. Formulations also followed industrial constraints.

Lubricants developed proved to be in accordance with the bio-degradability and toxicity test that were set within the project to consider the product as bio-degradable, mainly in accordance with ECOLABEL specifications. Concerning eco-toxicity, they were tested against daphnia-magna tests. Concerning performance, all lubricants showed similar or better behaviour than their counterparts at real tests.

Tekniker, in collaboration with Monition, developed a software prototype for the management of tribology data with clear links to the condition monitoring strategies to be used across different types of industry based on industry type and operating environment. Embedded within the software was an expert system for use in diagnosing actions from the results of analysis and also the strategy employed.

The exploitable result was a series of default alarm levels against which to measure the operating condition of lubricants. These alarm levels were based on the measurement of wear elements, as exhibited by the six most common machine components:

1. plain bearings
2. gearbox (simple)
3. gearbox (Radicon)
4. pumps / compressors
5. engines
6. hydraulic systems.

Monition derived a formula to correctly identify the correct lubricant sampling frequency from a machine, based on environmental conditions, the industry, criticality of the plant item / components and default oil sampling frequency for the component. Used within a robust software system, this formula would enable plant / maintenance personnel to determine how regularly they need to conduct oil analysis from a particular machine, based on the information they input to the system for each of the above parameters (environment conditions, industry etc.).

Informations connexes

Reported by

ROWE MINERALOLWERK GMBH
BUBENHEIM
Germany