Where there s muck there s brass

Transcription

1 Where there s muck there s brass Ian Wilson Department of Chemical Engineering & Biotechnology diw11@cam.ac.uk 23 September 2011

2 Life is mucky John Chew,

3 How much soap? UK estimate 37% of households own a dishwasher 9 million appliances litres per wash 60, ,000 tonnes of water per day UK uses ~50,000 tonnes of dishwasher powder per year UK uses ~100,000 tonnes of hand wash liquid 3

4 The challenge : green cleaning Cleaning uses large amounts of chemicals solvents energy How do we reduce these costs and environmental impacts? cleverer chemicals water low temperature other forms of energy 4

5 An ongoing challenge ,1998, 2002, 2006, 2010 Department of Chemical Engineering, Cambridge 5

6 What is Clean? adj, free from dirt or contaminating matter, unsoiled Process efficiency returned Product contaminant free No microbial survival Optically clean No microbial growth or spores : micro-clean Nutrient clean Nano-clean : no salts or films DI Wilson,

7 Cleaning science: surfaces & interfaces solution soil substrate 7

8 Cleaning method (1): thermodynamics solution soil substrate 8

9 Dissolution How? Can t change the soil Substrate? Solvents : oxygen dihydride? Can change the temperature Energy Clever chemicals - surfactants solution soil substrate 9

10 Cleaning method (2): erosion solution soil substrate 2 nd Law of Thermodynamics : Tha don t get owt for nowt! 10

11 Crude FC Oil refinery crude preheat train de-salter pump $$$$ furnace fuel flash distillation 11

12 Thinking outside the little box.. Ultrasonic cleaning of heat exchangers Tech Sonic Solutions, Canada

13 Promoting erosion Break down the soil.. make it weaker solution soil soil substrate 13

14 C.R. Gillham,

15 The soft tissue issue How do you measure soft layers immersed in liquid in situ in real time inexpensively? Baptiste Salley,

16 our way.. fluid dynamic gauging John Chew (2004) 16

17 FDG P 2 m flow d t P 1 h h o δ = h o - h FDG can measure: Soft deposit thickness and strength In real time, in situ, during a cleaning process P.W. Gordon et al. (2010) Food Bioproducts Proc., 81,

18 FDG today : scanning, ± 5 micron 18

19 Patrick Gordon and Akin Ali,

20 50 mm Patrick Gordon and Akin Ali,

21 Patrick Gordon and Akin Ali,

22 Patrick Gordon and Akin Ali,

23 Patrick Gordon and Akin Ali,

24 Patrick Gordon and Akin Ali,

25 Patrick Gordon and Akin Ali,

26 Patrick Gordon and Akin Ali,

27 Back to cleaning 150 C + 0 h 1 h 2 h Patrick Gordon, 2010,

28 Patrick Gordon, 2010 unbaked egg yolk 40 C ph 10.8 PXPS protease P.W. Gordon et al. (2011) Chem. Eng. Res. Des., /j.cherd

29 Design detergents soak & swell release enzyme rinse off 29

30 Cleaning method (3): rejection solution soil substrate.. change adhesion to substrate.. diffusion through a swelling matrix surface energies 30

31 Cleaning polymerisation reactors John Chew (2005) Aim: replace methylethylketone (MEK) with aqueous cleaners 31

32 Products PX and PA δ o = 50 µm Y.M.J. Chew et al. (2005) Ind. Eng. Chem. Res., 44,

33 Simulating liquid flow John Chew,

34 Simulating liquid flow Calculate wall shear stress Y.M.J. Chew et al. (2004) J. Food Engineering, 65(2),

35 Surface Treatment Tomato paste layers on treated stainless steels P Saikhwan et al. (2006) Surfaces Coating Tech., 210,

36 A baking oven 36

37 spray to wet all surfaces rinse off loose soil Dishwasher picture wetting surface to promote swelling & dissolution use T and ph triggers to start next phase angled surfaces to form falling films 37

38 Closing remarks There is a lot of cleaning going on Clean means different things to different people There is more than one way to clean Cleaning is a truly interdisciplinary subject You can be green and clean! 38

39 the Muckers the Craftsmen: Andy Hubbard and Surinder Sall P&G Dave York & Anju Brooker 39