Electro-osmosis Dewatering as an Energy Efficient Technology for - - PowerPoint PPT Presentation

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Electro-osmosis Dewatering as an Energy Efficient Technology for - - PowerPoint PPT Presentation

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2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Electro-osmosis Dewatering as an Energy Efficient Technology for Drying Food Materials Abhay Menon, Tonderai Reuben Mashyamombe, and Valentina Stojceska*

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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

Electro-osmosis Dewatering as an Energy Efficient Technology for Drying Food Materials

Abhay Menon, Tonderai Reuben Mashyamombe, and Valentina Stojceska*

Institute for Energy Futures, Brunel University London Paphos, 18th October 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

Institute of Energy Futures, Brunel University London

  • Economic and environmental impacts of high

energy use in UK food industries.

  • Policies implemented by UK Government to

solve this problem

  • Introduction to electro osmosis (EO) dewatering

technology

  • Design and setup of electro-osmotic dewatering

system

  • Experimental parameters and food products

used for dewatering

  • Performance

evaluation and comparison

  • f

moisture losses, energy consumption, tariffs and environmental impact of EO with thermal drying.

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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

Energy consumption in UK food industries

  • It is estimated that food chains are responsible for 18 % of total UK energy use

with ca. 176 MtCO2e emissions [1].

Institute of Energy Futures, Brunel University London

  • Approximately 65 % of total energy use in food industries are consumed in food

manufacture and processing.

  • A huge proportion of this energy (36%) is consumed by heating processes

(dryers, boilers, pre-treatment, coating etc.).

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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

Government regulations imposed on UK food industries

  • UK was the first country to imply Carbon budgets (Climate change act, 2008) to

curb the greenhouse gases that an organization can emit. The 3rd Carbon budget (2018-2020) has proposed to reduce the GHG emissions by 37% from year 1990’s level.

  • UK is committed to reducing 10-15 % of energy consumption and water usage by

2020, in agreement with Kyoto protocol (EU, 2012).

Institute of Energy Futures, Brunel University London

25 % below 1990 levels 31 % below 1990 levels 37 % below 1990 levels 51 % below 1990 levels 57 % below 1990 levels

  • 300

200 700 1200 1700 2200 2700 3200 1st Carbon budget (2008 to 2012) 2nd Carbon budget (2013 to 2017) 3rd Carbon budget (2018 to 2022) 4th Carbon budget (2023 to 2027) 5th Carbon budget (2028 to 2032) Budgeted level of carbon dioxide emission (MtCO2e)

UK Carbon Budget forecasts (Climate Change Act, 2008)

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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

Institute of Energy Futures, Brunel University London

  • Drying uses 12-20 % of the total energy

consumed in food manufacturing industries [2].

  • Over 85 % of all industrial dryers are

thermal based with energy efficiency values as low as 30 % [3].

  • With such high GHG emissions and high

costs incurred, the development

  • f

innovative drying technology with higher energy efficiency for food industries have become imperative.

Image source: Amisy, China

  • Hybrid dryers
  • Spray dryers
  • Freeze dryers
  • Heat pump dryers
  • Microwave based dryers
  • Infrared dryers
  • Vacuum dryers
  • Adsorption dryers
  • Refractance window drying
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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

Electro-osmosis dewatering system

Institute of Energy Futures, Brunel University London

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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

Mechanical hoist Water outlet Beaker Water outlet Dewatered moisture

Institute of Energy Futures, Brunel University London

Temperature probe pH meter Food material (+) (-)

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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

Food materials analysed and parameters

Institute of Energy Futures, Brunel University London

Egg whites Exposure time (min) Voltage (V) 15 15 30 30 Orang juice (pulp) Yogurt

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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

Moisture loss after dewatering

Institute of Energy Futures, Brunel University London

83.74a 59.86d 75.65c 71.76cd 80.41ab 68.80c 76.45b 20 40 60 80 100 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min

Moisture content (%)

Yogurt

76.58a 74.13ab 76.10a 75.69a 76.24a 75.61a 76.24a 20 40 60 80 100 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min

Moisture content (%)

Egg whites

90.71a 89.85a 90.21a 90.25a 90.56a 90.07a 90.46a 20 40 60 80 100 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min

Moisture content (%)

Orange juice

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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

EO/ Thermal dewatering Energy and Cost evaluation

The yearly evaluation of the performance of EO were calculated based on the following assumption;

  • Both EO and Thermal dryers were used on an average of 8 h a day, for 253 days

excluding weekends and bank holidays

  • The unit rate for power consumption commercially is estimated as £0.11676

(npower, United Kingdom 2017)

  • Therefore, the assumed working hours (X) per year is;

X= 8 * 253= 2024 h The electrical energy (E) in kWh is calculated based on the following equation where Voltage (V) is constant and Current (I) is measured [4];

𝐹 = ׬

𝑊∗𝐽 1000 𝑒𝑢

Institute of Energy Futures, Brunel University London

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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

Electrical energy consumption per year

Institute of Energy Futures, Brunel University London

91 40 198 52 1012 26 12 200 400 600 800 1000 1200 EO 30V EO 15V T

Electrical energy consumed (kWh)

Yogurt Egg whites Orange juice

Electro-osmosis Thermal

Ep.y= E * X

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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

Institute of Energy Futures, Brunel University London

Cost evaluation

Operating parameter Cost per year in GBP. Yog 30 V £ 23.16 Yog 15 V £ 6.14 E W 30 V £ 3.07 E W 15 V £ 1.40 OJ 30 V £ 10.63 OJ 15 V £ 4.72 Thermal £ 118.16

An estimated reduction of 80%

  • perational

costs per annum could be achieved by implementing EO in industries! E O Costp.y=E * X * 0.11676

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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

Institute of Energy Futures, Brunel University London

Image source : Carbon trust

Carbon Footprint evaluation

Operating parameter Carbon dioxide emission (kgCO2e) Percentage differences with thermal drying (%)

Yog 30 V 56.04 81 Yog 15 V 14.71 95 E W 30 V 7.35 97 E W 15 V 3.39 99 OJ 30 V 26.32 91 OJ 15 V 11.32 93 Thermal 286.46

The emission conversion factor for electricity is 0.28307 kgCO2e per kWh unit

  • f

consumption (Department of Environment Food and Rural Affairs, UK, 2018). CFE= 0.28307 * Ep.y

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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

Institute of Energy Futures, Brunel University London

Changes in pH during drying

2 4 6 8 10 12 14

pH

Yogurt 15 V Yogurt 30 V 2 4 6 8 10 12 14

pH

Egg whites 15 V Egg whites 30 V 2 4 6 8 10 12 14 5 10 15 20 25 30

pH Time (min)

Orange juice 15 V Orange juice 30 V

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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

Institute of Energy Futures, Brunel University London

Conclusions

  • A

laboratory scale model

  • f

electro-osmosis dewatering system was successfully implemented.

  • Results showed enhanced energy efficiency, low costs and reduced carbon

footprints.

  • Among the three food materials tested, the moisture content after dewatering

showed a significant reduction and pH values varied depending on the extent of electro-osmotic flow of water and electrical interferences with food matrix.

  • Prolonged exposure with high potential (30 min 30 V) showed an enhanced

dewatering rate compared to lower settings.

  • Future research on EO shall be focussed on analysing the quality aspects

(phenolic compounds, AO, sensory evaluation etc.) of food materials after dewatering.

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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

Institute of Energy Futures, Brunel University London

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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

References

1.

  • S. A. Tassou, M. Kolokotroni, B. Gowreesunker, V. Stojceska, A. Azapagic, P. Fryer and S.

Bakalis, "Energy demand and reduction opportunities in the UK food chain," Energy, vol. 167, no. EN3, pp. 162-170, 2014. 2.

  • G. Raghavan, T. Rennie, P. Sunjka, V. Orsat, W. Phaphuangwittayakul and P. Terdtoon,

“Overview of new techniques for drying biological materials with emphasis on energy aspects," Brazilian Journal of Chemical Engineering, vol. 22, no. 2, pp. 195 - 201, 2005. 3.

  • N. Tippayawong, C. Tantakitti and S. Thavornun, "Energy efficiency improvements in

longan drying practice," Energy, vol. 33, no. 7, pp. 1137-1143, 2008. 4.

  • S. K. Ng, A. Plunkett, V. Stojceska, P. Ainsworth, J. Lamont-Black, J. Hall , C. White, S.

Glendenning and D. Russell, “Electro-kinetic technology as a low-cost method for dewatering food by-product,” Drying Technology, vol. 29, pp. 1722-1728, 2011.

Institute of Energy Futures, Brunel University London