To this day, mineral oil is the most important basis for technical lubricants. These include hydraulic fluids and cooling lubricants. However, only in Germany, around 250,000 to 500,000 tons are not returned to the used oil cycle each year and end up in the environment via various routes. While environmentally friendly hydraulic fluids with a high water content are already available on the market, these usually require the use of biocides of human toxicological concern in order to be protected against microbial infestation. Overall, there is a need to develop a biocide-free hydraulic fluid based on renewable raw materials. In the past, a corresponding fluid was developed at Technische Universität Braunschweig, which is comparable to conventional fluids in terms of fluid properties. This fluid was produced from the main components water and glycerine as well as a chitosan derivative as thickener.With the fluid developed, it was possible to set viscosities of up to 46 cSt that are relevant in practice. In addition, it was observed that the base fluid had an excellent corrosion protection effect and a base pH even without an additive. In addition, the base fluid was protected against microbial attack without an addition of additives. Due to the positive properties of the base fluid, only a very small amount of performance additives was required. In extensive laboratory tests, the experimental fluid was able to compete with comparable commercial fluids. In addition, a simple model hydraulic system could be operated with the fluid several times over several weeks without malfunction. The technical performance of the fluid was thus confirmed.&nbsp; Due to the promising properties of the fluid and the interim results achieved, the Institut für Ökologische und Nachhaltige Chemie and the Institut für mobile Maschinen und Nutzfahrzeuge at Technische Universität Braunschweig are working together with industrial partners on further development of the fluid for use in mobile and stationary machinery. The focus here is on further development for practical use in mobile hydraulic systems of, for example, agricultural and forestry machinery. The aim is to optimize various fluid variants for different applications and to define the possible range of applications in general.Different fluid variants are to be investigated in various test rigs suitable for use in the field under realistic conditions compared with commercial fluids as reference. Accompanying the investigations on the test rig, investigations of the fluid will be carried out on a laboratory scale. These should enable the detection of possible changes in the fluid properties. In addition, the development of the efficiencies and the wear development of the hydraulic machines will be recorded. On the basis of the measured data from the laboratory tests and the measured data from the test bench trials, it will be possible to determine how the experimental fluid should be added for practical applications and how hydraulic systems should be adapted to enable operation with the new type of fluid. In addition, the influence of the novel fluid on the operating costs compared to the use of commercial reference fluids will be investigated.

Development of Glycerin/Chitosan-Based Fluids for Stationary and Mobile Hydraulic Drives

Paper Proceedings: https://asmedigitalcollection.asme.org/FPST/FPMC2021/volume/85239

2021 ASME/BATH Symposium on Fluid Power and Motion Control (FPMC2021)

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