Institute of Chemical Engineering page 1 Achema 2012 Mechanical Process Engineering Dipl.-Ing. Dr. Thomas Laminger Univ. Prof. Dr. Wilhelm Höflinger Contact: Characterization and Separation of Metal Working Fluid Mist

Institute of Chemical Engineering page 2 Achema 2012 Mechanical Process Engineering During machining fine droplets and vapor of metalworking fluids (MWF) are generated by the rotating tool or grinding wheel which can cause occupational health problems. MWF are complex mixtures that could contain petroleum products, animal and vegetable fats and variety of additives to improve their properties. They are utilized either as pure oils or as emulsions of oil in water (range 1-10 %). Background Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 3 Achema 2012 Mechanical Process Engineering Workers are usually exposed to MWFs by inhalation and through skin contact, which can cause a variety of health problems: dermatitis, respiratory problems and long –term exposure can lead to several cancer types. For this reason it is very important to determine appropriate ventilation system: full enclosed housings half enclosed housings with appropriate filter elements to reduce working areas air contamination Background Without any enclosures Full enclosed housing Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 4 Achema 2012 Mechanical Process Engineering The range of installed filter medias, used oil/emulsions and working processes is very wide. But still there are no standards to test and certificate these MWF mist filters filter medias. Development of standard characterization method of MWF mist filters Introduction and purpose of the study Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 5 Achema 2012 Mechanical Process Engineering Characterization of metal working fluid mist filters using a filter test rig To characterize and compare different filter media a filter test rig was build up. Measured parameters are e.g. pressure drop, separation efficiency and drainage flow. flow velocity p blower MWF pump Filter holder with test elements Aerosol generator Metalworking fluid mist Drainage flow Aerosol measurement CYCL-FID Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 6 Achema 2012 Mechanical Process Engineering Filter test rig Aerosol- generator Data acquisition Filter holder and suck off pipe Aerosol measurement Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 7 Achema 2012 Mechanical Process Engineering Aerosol measurement device CYCL-FID For an on-line detection of MWF-mist emissions a new measurement method was established. To detect vapour and droplet phase a combination of a classifier, evaporator and flame-ionization-detector was built up. A cyclone as classifier allows a continuous change of the Cut-Off-diameter by changing the air flow by the cyclone. CYCL-FID-Measurement Ingoing air flow PM1 Cyclone FIDPCS Flow Valve for air flow control Suck off pipe Optional PCS for calibration Sampling and measurement Sampling Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 8 Achema 2012 Mechanical Process Engineering Characterization and separation of metal working fluid mist CYCL-FID-Measurement Using different Cut-Off-Sizes the MWF-Emission is sequential classified and detected after evaporation with the FID. For example a MWF-Emission is classified using 3 different Cut-Off-Sizes: FID 1,0 FID 2,5 FID All FID 0,5 Cut-Off 1,0µm Cut-Off 2,5µm No Cut-Off MWF-Emission 0,5 – 1,0 µm 1,0 – 2,5 µm>2,5 µm Vapor+ 0-0,5µm Cut-Off 0,5µm 4 FID-Signals: Vapor + 0-0,5µm Vapor + 0-2,5µm Vapor + 0-1,0µm Vapor + 0- >2,5µm Vapor and Droplets

Institute of Chemical Engineering page 9 Achema 2012 Mechanical Process Engineering Characterization and separation of metal working fluid mist CYCL-FID-Measurement By subtracting two classified FID-Signals a Droplet-Size-Distribution can be calculated. Vapor is per definition part of the smallest used Cut-Off-Size Cut-Off [µm] FID Signal (ppm propane-equivalent) FID 1,0 FID 2,5 FID 5,0 FID 0,5 0,51,02,5Aerodynamic diameter [µm] FID 0,5FID 1,0 – FID 0,5FID 2,5 – FID 1,0FID 5,0– FID 2,5 FID ALL 5,0 FID ALL– FID 5,0 Vapor + droplets <0,5µm 0,51,02,55,0 FID Signal (ppm propane-equivalent)

Institute of Chemical Engineering page 10 Achema 2012 Mechanical Process Engineering Filter-class Minimal requested separation efficiency (%) in the steady state condition <0.3µm (including vapor) 0.3-1µm1-3µm3-10µm 1 --0E3<350E4< E3<4550E4< E2<3545E3<5560E4< E2<4555E3<6570E4< E2<5565E3<7580E4< E2<6575E3<8585E4<90 7 0E1<565E2<7585E3<9090E4<95 8 5E1<1075E2<8590E3<9595E4 9 10E1<2085E2<9595E395E E195E295E395E4 PROPOSAL OF A CLASSIFICATION SYSTEM FOR METAL WORKING FLUID MIST SEPARATORS Filter-classes: 1-3: Pre-Separators, Coarse wire mesh … 4-6: Coarse glass-fiber filter, wire/glass-fibre filters … 7-10: Fine glass-fiber filters, HEPA filters … Further report values: Airflow rate, Test substance, stationary pressure drop, total holdup, oil holdup … Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 11 Achema 2012 Mechanical Process Engineering B A ACCELERATED FILTER AGEING TEST PROCEDURE The same stationary pressure drop is achieved with (A) accelerated and (B) non accelerated filter ageing procedure. 1)Accelerated Ageing transfer the filter in a stationary condition using the ageing nozzle and the aerosol generator 2) Stabilizing shut down of the ageing nozzle – using only the aerosol generator 3) Measuring measuring the stationary raw and clean gas concentration with the CYCL-FID-measurement device (only the aerosol generator) Ageing nozzle: shortens the ageing time Aerosol generator: generates the test aerosol 3-step test procedure Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 12 Achema 2012 Mechanical Process Engineering DEMONSTRATIVE MEASUREMENT EXAMPLE Test filter Fine wire/glass-fiber filter, 200x200x40mm Test parameters Filter face velocity: 5000m³/(m²h) Test substance: 10% emulsion, mineral oil Filter loading (with ageing nozzle): 0.5g/(cm²/min) Test aerosol concentration: 56mg/m³ Test aerosol: Particle size distribution (PCS 2010, Palas ®) Aerosol generator: 7500rpm; 1.2L/min emulsion flow Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 13 Achema 2012 Mechanical Process Engineering TIME DEVELOPMENT AND STATIONARY VALUES OF THE PRESSURE DROP, TOTAL HOLDUP AND OIL HOLDUP Stabilizing Accelerated Ageing Measuring Pressure drop Total holdup Oil holdup Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 14 Achema 2012 Mechanical Process Engineering STATIONARY RAW GAS AND CLEN GAS CONCENTRATION AND THE FRACTIONAL SEPARATION EFFICIENCY IN FOUR FRACTIONS Filter- class Minimal requested separation efficiency (%) <0.3µm0.3-1µm1-3µm3-10µm 1 --0E3<350E4< E3<4550E4< E2<3545E3<5560E4< E2<4555E3<6570E4< E2<5565E3<7580E4< E2<6575E3<8585E4<90 7 0E1<565E2<7585E3<9090E4<95 8 5E1<1075E2<8590E3<9595E4 9 10E1<2085E2<9595E395E E195E295E395E4 Filter reach Filter-class 7 Characterization and separation of metal working fluid mist

Institute of Chemical Engineering page 15 Achema 2012 Mechanical Process Engineering SUMMARY In analogy to existing norms and standards for dust filters a standardized test procedure for metal working fluid mist filters was developed: A filter test rig with its main components was presented. The CYCL-FID-measurement device and the principle to measure the droplet and vapor concentration of a mist emission in several particle size fractions was shown. A three-step filter test procedure (accelerated filter ageing) was described using an ageing nozzle which allows the determination of the stationary filtration specific parameters which are pressure drop, total holdup, oil holdup and the fractional separation efficiency in a relative short test time. A classification system with 10 filter-classes for MWF mist filters was proposed. The system includes four particle size ranges (<0,3µm/0.3-1µm/1-3µm/3-10µm) with minimal requested separation efficiencies. The particle size range <0.3µm includes also the vapor fraction of the mist emission. With the filter test rig, the developed accelerated filter ageing procedure and the classification system it is now possible to evaluate and compare different mist separators in a very short time. Characterization and separation of metal working fluid mist