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How might surface properties affect cleaning performance? Alejandro - - PowerPoint PPT Presentation

Jul 05, 2023 42 likes •208 views

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains How might surface properties affect cleaning performance? Alejandro Avila-Sierra*, Zhenyu J. Zhang, Peter J. Fryer University of Birmingham, United Kingdom

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2nd International Conference on Sustainable Energy and Resource Use in Food Chains

RCUK Centre for Sustainable Energy Use in Food Chains

Alejandro Avila-Sierra*, Zhenyu J. Zhang, Peter J. Fryer

University of Birmingham, United Kingdom Cyprus, 2018

How might surface properties affect cleaning performance?

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Cleaning in place system (CIP)

2 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Example of CIP system. Image from Sanimatic

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Fouling problems

  • Depends on the type of product processed and surface -

3 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Fluid Flow – Pipes – Substrate

  • Stainless steel 304/316L -

Deposit Removal

Types of foulant. Image from Laboratory of Colloid and Surface Chemistry (LCSC) Schematic diagram of foulant deposition

Foulant Deposition

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Fouling on heat exchanger

  • Dairy industry -

4 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Milk fouling after 8 hours processing on heat exchanger before (A & C) and after anti-fouling coating (B & D)

  • application. Image from Anti-Fouling, Heat Exchanger Solutions Inc.
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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Key question:

5 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

How might surface properties affect cleaning performance?

  • To understand what we have
  • To know what we can do

Natural characteristics of each substrate: Surface free energy (related with composition) External variables (can be modified): Surface temperature (25-80°C) Topography of the surface – Roughness (Ra<0.8µm)

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

6 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Surface roughness

(A) (B) (C)

Surface roughness of the used surfaces:

  • mirror (A) [Ra 0.0295 ± 0.0045µm]
  • satin (B)

[Ra 0.3090 ± 0.0095µm]

  • brush (C)

[Ra 0.8250 ± 0.1276µm] Characterised by Interferometry.

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

7 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Wettability of liquids

  • Liquids selected -

Boiling temperature and surface tension of liquids tested. Surface tension measured at room temperature.

Liquid Boiling point (°C) Surface tension (mN/m) Ethylene glycol 197 47.47 Diiodomethane 181 50.00 1- Bromonaphthalene 135 44.63 Water 100 72.10

Polar

  • Ethylene glycol
  • Distilled Water

Non-polar

  • Diiodomethane
  • 1-Bromonaphthalene

Liquids commonly used to characterise Surface Free Energy

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

8 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Equilibrium Contact Angle

  • Method -

Thermal bath Heating stage High Speed Camera (1000fps)

  • Atmospheric pressure
  • No saturation conditions
  • Temperature range: 25 - 80°C
  • Liquid drop is sufficiently small to

avoid gravity effect Stainless steel coupon 10µL of liquid

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

9 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

ECA measurements

Equilibrium contact angle of liquids as a function

  • f

temperature on three different types of polished surfaces: Mirror Satin Brush Liquids tested:

  • Ethylene glycol (A)
  • 1-Bromonaphthalene (B)
  • Diiodomethane (C)
  • Distilled water (D)

20 30 40 50 20 40 60 80 Contact angle (°) Temperature (°C) 10 20 30 40 20 40 60 80 Contact angle (°) Temperature (°C) 30 40 50 20 40 60 80 Contact angle (°) Temperature (°C) 40 50 60 70 80 20 40 60 80 Contact angle (°) Temperature (°C)

(A) (B) (C) (D)

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Modelling

  • ECA as a function of temperature-

10 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

As shown in previous studies [1][2], it is possible to describe the contact angle’s temperature dependence of liquids on several substrates.

  • The sharp-kink approximation (SK) [1] (considering only Van der Waals type forces):

cos θ = −1 + ∆ρ·I / γlv (Eq. 1)

  • Decreasing Trend Model (DTm) [2]. The model has two formulations depending on the type of liquid used,

non-polar (Eq. 2) or polar (Eq. 3). Surface tension of the solid can be extrapolating from ambient conditions. cos𝜄 = −1 + 2 ·

𝛿𝑡𝑤 𝛿𝑚𝑤

(Eq. 2) cos𝜄 = −1 +

2

𝛿𝑚𝑤 ∙ 𝛿𝑡𝑤

𝐸 ∙ 𝛿𝑚𝑤

𝐸

𝛿𝑚𝑤 + 𝛿𝑡𝑤 𝑄 ∙ 𝛿𝑚𝑤

𝑄

𝛿𝑚𝑤

(Eq. 3)

[1]

  • R. Garcia, K. Osborne, and E. Subashi, “Validity of the ‘ Sharp-Kink Approximation ’ for Water and Other Fluids,” J. Phys. Chem., vol. 112, pp. 8114–8119, 2008.

[2]

  • F. Villa, M. Marengo, and J. De Coninck, “A new model to predict the influence of surface temperature on contact angle,” Sci. Reports Nat., vol. 8, no. 6549, pp. 1–10, 2018.
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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Modelling

11 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

A & B) Modelling of ECA average as a function of wall temperature for real food-contact surfaces (Ra<0.8 µm). Liquids tested: Water Diiodomethane 1-Bromonaphthalene

□ Ethylene glycol

C & D) Modelling of water ECA as a function of both wall temperature and surface roughness: Mirror Satin Brush SK approximation model (A and C). DT model (B and D).

20 40 60 80 20 40 60 80 Contact angle (⁰) Temperature (⁰C) 40 50 60 70 80 20 30 40 50 60 Contact angle (⁰) Temperature (⁰C) 40 50 60 70 80 20 30 40 50 60 Contact angle (⁰) Temperature (⁰C)

(B) (C) (D)

20 40 60 80 20 40 60 80 Contact angle (⁰) Temperature (⁰C)

(A)

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Characterisation of SFE

  • Methods-

12 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

In this work, 1- bromonaphthalene and ethylene glycol were the liquids selected to characterise solid SFE with polar and disperse components. The two methods used to calculate and compare SFE are:

  • Owens & Wendt method and Wu method [3]

𝛿𝑚𝑤 1+ 𝑑𝑝𝑡 θ = 2 𝛿𝑡𝑤𝐸 ∙ 𝛿𝑚𝑤𝐸 + 2 𝛿𝑡𝑤𝑄 ∙ 𝛿𝑚𝑤𝑄

  • Wu method [4][5]

𝛿𝑚𝑤 1+ 𝑑𝑝𝑡 θ = 4 ∙ 𝛿𝑡𝑤

𝐸 ∙ 𝛿𝑚𝑤𝐸

𝛿𝑡𝑤𝐸 + 𝛿𝑚𝑤𝐸 + 4 ∙ 𝛿𝑡𝑤𝑄 ∙ 𝛿𝑚𝑤𝑄 𝛿𝑡𝑤𝑄 + 𝛿𝑚𝑤𝑄

γlv: Surface tension liquid-air; θ: equilibrium contact angle; γsv: surface tension sold−air

Wu harmonic mean model often provides more reliable values between both parts -for low surface free energies systems (up to 40 mJ/m2), than the geometric mean approach.

[3]

  • D. Owens and R. Wendt, “Estimation of the surface free energy of polymers,” J. Appl. Polym. Sci., vol. 13, no. 8, pp. 1741–1747, 1969.

[4]

  • S. Wu, “Calculation of interfacial tension in polymer systems,” J. Polym. Sci. Polym. Symp., vol. 34, no. 1, pp. 19–30, 1971.

[5]

  • S. Wu, “Polar and Nonpolar Interactions in Adhesion,” J. Adhes., vol. 5, no. 1, pp. 39–55, 1973.
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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Characterisation of SFE

13 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

Average of solid surface free energy as a function of temperature on three different types of polished surfaces.

  • Total SFE
  • Polar part
  • Disperse part

Liquids tested: Ethylene glycol and 1-Bromonaphthalene. Methods: Owens & Wendt (A); Wu method (B). 10 20 30 40 50 20 40 60 80 Solid SFE (mN/m) Temperature (°C) 10 20 30 40 50 20 40 60 80 Solid SFE (mN/m) Temperature (°C)

(A) (B)

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

SFE as a function of roughness

14 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

0% 1% 2% 3% 0.2 0.4 0.6 0.8 SFE increase Ra (µm)

Surface free energy increase (%) of SS316L as a function of surface roughness. Methods: Owens &Wendt method Wu method Liquids tested: Ethylene glycol and 1-Bromonaphthalene.

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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Summarise

15 Alejandro Avila-Sierra axa1312@student.bham.ac.uk

PART 1 – Wettability

  • Contact angle of liquids decreases with increasing of wall temperature on hydrophilic surfaces.
  • The highest contact angle was found for the smoothest surface, decreasing its values as a function of the

surface roughness increase.

  • ECA of liquids with high surface tension values changes considerably for small roughness variations.
  • The increase of water ECA shows a relationship between temperature and roughness, being that increase

produced at lower temperatures for higher roughness values. Then, roughness influences directly on the evaporation of water.

  • Wettability is favoured by the increase of both temperature and roughness.

PART 2 – Modelling

  • Successful approaches regarding wall temperature and surface roughness.
  • Selection of the right liquids system to quantify SFE of substrates is essential.
  • It appears that the system consisting of ethylene glycol or 1-bromonaphthalene is the most appropriate to

calculate the surface free energy of solid as a function of temperature and roughness. PART 3 – Surface free energy

  • Surface free energy of stainless steel remains constant as a function of temperature.
  • There is a roughness-dependence of the metal surface free energy.
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RCUK Centre for Sustainable Energy Use in Food Chains

2nd International Conference on Sustainable Energy and Resource Use in Food Chains

Thanks for your attention!

16 Alejandro Avila-Sierra axa1312@student.bham.ac.uk