Development of an innovative process for economically and ecologically disposing of cooling lubricant waste

Objectif

Initially, the basic requirements to be met by the process will be identified and the cooling lubricants of relevance to the disposal process will be selected and characterised. The cooling lubricant selected, was used in a laboratory and engineering institute facility. The most effective process parameters and the layout of the pilot plant were defined on the basis of these results and the theoretical calculations. In contrast to the original process principle - after the cooling lubricant to be disposed of had been converted into a hydroxide melt - the LuxoTherm-process was modified for economic, process engineering and safety reasons. Accordingly, the LuxoTherm process has been designed so as to ensure that the lubricant requiring disposal, is first pyrolysed then gasified in a closed reactor at temperatures ranging from 750°-850°C on a CaO fixed bed under from which oxygen is excluded.

A product gas with a high hydrogen content is formed depending on the cooling lubricant used and on reaction conditions. The CaO acts as a heat transfer medium, as a catalyst for the gasification reactions and a reaction partner for heteroatoms, which are carried over and are present in the form of simple calcium sodium after the reaction. On investigation of the gasification reaction, it was discovered that the proportion of water carried into the reaction process is decisive for the proportion of the solid reaction product formed (C) and for the volume of product gas. Water carried in, reacts with the carbon formed and methane to form hydrogen, carbon monoxide and carbon dioxide in accordance with the familiar patterns. All cooling lubricants selected, were converted successfully.

It was not possible to set up the LuxoTherm prototype or to carry out the field test subsequently planned, within the duration of the project. Plans for execution of this project work at a later date, have been drawn up.
The objective of the project planned is the development of an innovative process for economically and ecologically disposing of used cooling lubricants.Cooling lubricants/oils are found in a variety of applications and are particularly found in use in cutting processes such as drilling, milling or grinding. In Germany alone, more than 500,000 t (tons) of cooling lubricants are used in industrial production processes annually /1/. The large amounts of used lubricants as well as increasing disposal costs mean that cooling lubricants are of great importance for manufacturers, both economically as well as ecologically. The costs for disposing a cubic meter of used cooling lubricant varies between 80 ECU (slightly soiled materials) and 1580 ECU/m3 (heavily polluted materials) /3/. The cutting and forming processes are among the most used metal machining operations across the whole of Europe. The need for environmentally and economically viable disposal of these materials is of particular importance in the automobile, engineering and plant manufacturing industries. The concept based on the Luxotherm process offers a method for recycling both, the aqueous and oil phase of used cooling lubricants cost effectively and decentrally. Firstly, the aqueous phase is separated from the oil phase via a spray evaporation technique. Because of the high quality of the resultant water, it can be used in other production processes, for instance, the manufacturing of new cooling lubricants or, as a substitute for deionised water, for rinsing after a degreasing process. The waste oil (oil phase) can be processed in an environmentally friendly manner in a special reactor containing an alkaline melt without an oxygen supply and heated to approximately 800°C at normal pressure. The resulting product is an energy rich process gas containing hydrogen and methane. Alkaline hydrides, a side product, can be separated from the process gas flow. The results of the feasability study (exploratory phase) show that the synthtetic gas, that can be gained by the conversion of 1 lifer of used oil phase, contains a heating value of 11,7 kWh. Solid residues, in the form of carbonates and chlorides, can be used in other technical applications. The objectives of the project can be summarized in the following way: Recycling of the aqueous phase to a degree of 100% Complete conversion of the oil phase into synthetic gas (90% hydrogen, 5% methane) Usage of synthetic gas to a degree of 100% in terms of energy production or as process gas industrial applications Usage of solid side products (carbonates, metallic hydrides) in technical application to 100% Development of an economical alternative process for cooling lubricant disposal (reduction of processing costs and transport costs, sale and usage of secondary products) Through the inclusion of industrial partners along the life path of lubricant coolants (7 industrial partners of 4 European countries), it is also ensured that, from a global perspective, an optimal concept is developed for the disposal of these media. In view of the protection of resource sources and disposal capacities, this approach represents an important contribution to sustainable development within the framework of industrial production.The studies relate to the topic point 1.2.3. S Industrial and Material Technologies, Working Program, edition 1994.

Champ scientifique

• engineering and technologyenvironmental engineeringwaste managementwaste treatment processesrecycling
• engineering and technologymechanical engineeringtribologylubrication
• natural scienceschemical sciencesinorganic chemistryinorganic compounds
• engineering and technologymechanical engineeringmanufacturing engineeringsubtractive manufacturing
• natural scienceschemical sciencesorganic chemistryaliphatic compounds

Programme(s)

• FP4-BRITE/EURAM 3 - Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Thème(s)

• 0102 - Development of clean production technologies

Appel à propositions

Régime de financement

Coordinateur

Participants (8)